WORKING VEHICLE AND ATTACHMENT USAGE SYSTEM

Description

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to techniques to use attachments on working vehicles.

2. Description of the Related Art

For example, the specification of U.S. Patent Application Publication No. 2022/412040 discloses a system to automatically determine the positions of attachments in the vicinity of a working vehicle. The system is such that a first communication unit (tool module) including a first acceleration sensor is provided on an attachment such as a bucket, a quick changer configured to quickly and simply attach and detach the attachment thereto and therefrom is provided at the distal end of the boom of the working vehicle (excavator), a second communication unit (receiving module) including a second acceleration sensor is provided at the quick changer, and the working vehicle is provided with an identification module and a controller.

The first communication unit transmits, to the second communication unit via a near field communication such as RFID or Bluetooth (registered trademark) Low Energy, a first acceleration signal relating to the instantaneous acceleration of the attachment detected by the first acceleration sensor and an identifying signal of the attachment. The second communication unit transmits, to the identification module, the first acceleration signal and the identifying signal received from the first communication unit and the second acceleration signal relating to the instantaneous acceleration of the quick changer detected by the second acceleration sensor. The identification module identifies the attachment attached to the quick changer based on the comparison (e.g., difference) between the first acceleration signal and the second acceleration signal received from the second communication unit and/or the received signal strength of the first acceleration signal, and transmits the identification information of the attachment to the controller. The controller performs an appropriate operation (work operation) of the working vehicle based on the received identifying signal.

However, in related systems as described above, although the distance between the quick changer and the attachment is determined based on the received signal strength of the first acceleration signal, even if the distance between the quick changer and the attachment is the same, the received strength signal of the first acceleration signal received by the second communication unit may vary depending on the position at which the second communication unit is attached and may change because of the action of the boom.

SUMMARY OF THE INVENTION

One or more example embodiments of the present invention make it possible to accurately detect an attachment attached to a linkage.

A working vehicle according to an example embodiment of the present invention includes a machine body, a position changer provided on the machine body, a linkage provided on the position changer to attach and detach an attachment thereto and therefrom, a receiver provided in or on the machine body to receive one or more wireless signals which are transmitted periodically from one or more transmitters in or on one or more of the attachments, which include respective one or more pieces of identification information of the one or more attachments, and which are compliant with a near field communication standard, and a controller configured or programmed to, based on one or more received signal strengths of the one or more wireless signals received by the receiver, select a piece of identification information of the attachment attached to the linkage and perform a predetermined process based on the selected piece of identification information, wherein the position changer is operable to be driven to change a relative position of the linkage relative to the machine body, and the controller is configured or programmed to select, based on a selection condition varying depending on the relative position, a piece of identification information included in a wireless signal with a received signal strength which satisfies the selection condition.

The controller may be configured or programmed to acquire a first threshold having a value that varies depending on the relative position. The selection condition may include a condition in which the piece of identification information to be selected by the controller is a piece of identification information included in a wireless signal with a received signal strength greater than the first threshold.

The controller may be configured or programmed to, when a relative distance between the machine body or the receiver and the linkage is a first distance, acquire the first threshold having a value less than when the relative distance is a second distance which is shorter than the first distance.

The position changer may include a boom supported on the machine body such that the boom is swingable up and down, and an arm swingably connected to a distal portion of the boom. The linkage may be swingably connected to a distal portion of the arm.

The working vehicle may further include a posture detector to detect a posture of the boom relative to the machine body and a posture of the arm relative to the boom. The controller may be configured or programmed to acquire the first threshold based on the posture of the boom and the posture of the arm detected by the posture detector.

The controller may be configured or programmed to acquire the first threshold by correcting a first reference value based on the posture of the boom and the posture of the arm.

The controller may be configured or programmed to acquire a first threshold having a value that varies depending on the relative position and a second threshold having a value that varies depending on the relative position, the second threshold being greater than the first threshold. The selection condition may include a condition in which the piece of identification information to be selected by the controller is a piece of identification information included in a wireless signal with a received signal strength greater than the first threshold and less than or equal to the second threshold.

The controller may be configured or programmed to, when a relative distance between the machine body or the receiver and the linkage is a first distance, acquire the first threshold and the second threshold which have respective values less than when the relative distance is a second distance which is shorter than the first distance.

The position changer may include a boom supported on the machine body such that the boom is swingable up and down, and an arm swingably connected to a distal portion of the boom. The linkage may be swingably connected to a distal portion of the arm.

The working vehicle may further include a posture detector to detect a posture of the boom relative to the machine body and a posture of the arm relative to the boom. The controller may be configured or programmed to acquire the first threshold and the second threshold based on the posture of the boom and the posture of the arm detected by the posture detector.

The controller may be configured or programmed to acquire the first threshold by correcting a first reference value based on the posture of the boom and the posture of the arm, and acquire the second threshold by correcting a second reference value based on the posture of the boom and the posture of the arm, the second reference value being greater than the first reference value.

The controller may be configured or programmed to acquire a second threshold having a value that varies depending on the relative position. The selection condition may include a condition in which the piece of identification information to be selected by the controller is a piece of identification information included in a wireless signal with a received signal strength less than or equal to the second threshold.

The controller may be configured or programmed to, when a relative distance between the machine body or the receiver and the linkage is a first distance, acquire the second threshold having a value less than when the relative distance is a second distance which is shorter than the first distance.

The position changer may include a boom supported on the machine body such that the boom is swingable up and down, and an arm swingably connected to a distal portion of the boom. The linkage may be swingably connected to a distal portion of the arm.

The working vehicle may further include a posture detector to detect a posture of the boom relative to the machine body and a posture of the arm relative to the boom. The controller may be configured or programmed to acquire the second threshold based on the posture of the boom and the posture of the arm detected by the posture detector.

The controller may be configured or programmed to acquire the second threshold by correcting a second reference value based on the posture of the boom and the posture of the arm.

The controller may be configured or programmed to correct the received signal strength based on a relative distance between the machine body or the receiver and the linkage. The selection condition may include a condition in which the piece of identification information is to be selected by the controller based on a value of the corrected received signal strength relative to a reference value.

The controller may be configured or programmed to correct the received signal strength such that the corrected received signal strength is greater when the relative distance is a first distance than when the relative distance is a second distance which is shorter than the first distance.

The position changer may include a boom supported on the machine body such that the boom is swingable up and down, and an arm swingably connected to a distal portion of the boom. The linkage may be swingably connected to a distal portion of the arm.

The working vehicle may further include a posture detector to detect a posture of the boom relative to the machine body and a posture of the arm relative to the boom. The controller may be configured or programmed to correct the received signal strength based on the posture of the boom and the posture of the arm detected by the posture detector.

The controller may be configured or programmed to acquire a first threshold as the reference value, and select a piece of identification information included in a wireless signal with a corrected received signal strength greater than the first threshold.

The controller may be configured or programmed to acquire, as a plurality of the reference values, a first threshold and a second threshold greater than the first threshold, and select a piece of identification information included in a wireless signal with a corrected received signal strength greater than the first threshold and less than or equal to the second threshold.

The controller may be configured or programmed to acquire a second threshold as the reference value, and select a piece of identification information included in a wireless signal with a corrected received signal strength less than or equal to the second threshold.

An attachment usage system according to an example embodiment of the present invention includes a position changer provided on a machine body of a working vehicle, a linkage provided on the position changer to attach and detach an attachment thereto and therefrom, one or more transmitters provided in or on one or more of the attachments to periodically transmit one or more wireless signals which include respective one or more pieces of identification information of the one or more attachments and which are compliant with a near field communication standard, a receiver provided in or on the machine body to receive the one or more wireless signals which are transmitted from the one or more transmitters, and a controller configured or programmed to, based on one or more received signal strengths of the one or more wireless signals received by the receiver, select a piece of identification information of the attachment attached to the linkage and perform a predetermined process based on the selected piece of identification information, wherein the position changer is operable to be driven to change a relative position of the linkage relative to the machine body, and the controller is configured or programmed to select, based on a selection condition varying depending on the relative position, a piece of identification information included in a wireless signal with a received signal strength which satisfies the selection condition.

The above and other elements, features, steps, characteristics and advantages of the present invention will become more apparent from the following detailed description of example embodiments with reference to the attached drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

A more complete appreciation of example embodiments of the present invention and many of the attendant advantages thereof will be readily obtained as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings described below.

FIG. 1 is a side view of a working vehicle.

FIG. 2A is a side view in which an attachment is released (not locked) by a quick hitch.

FIG. 2B is a side view in which an attachment is secured (locked) by a quick hitch.

FIG. 3 is a block diagram of an attachment usage system and a working vehicle.

FIG. 4 is a diagram showing an example of information included in an advertisement signal.

FIG. 5 is a graph showing the relationship between a first threshold and a relative distance.

FIG. 6 is a graph showing the relationship between a second threshold and a relative distance.

FIG. 7 is a diagram showing an example of the relationship between attachment IDs and their corresponding pieces of display data.

FIG. 8 is a diagram showing an example of the relationship between attachment IDs and their corresponding pieces of control data.

FIG. 9 is a flowchart showing an example of an attachment information collecting process.

FIG. 10 is a diagram showing an example of information stored in an internal memory of a controller.

FIG. 11 is a flowchart showing an example of a securing-of-attachment recognizing process.

FIG. 12 illustrates an example of an “attachment is attached” screen.

FIG. 13 is a screen showing an example of an attachment list.

FIG. 14 is a flowchart showing another example of an attachment information collecting process.

FIG. 15 is a flowchart showing another example of an attachment information collecting process.

FIG. 16 is a diagram showing another example of information stored in an internal memory of a controller.

FIG. 17 is a flowchart showing another example of a securing-of-attachment recognizing process.

FIG. 18 is a flowchart showing another example of a securing-of-attachment recognizing process.

FIG. 19 is a graph showing the relationship between a third correction value and a relative distance.

FIG. 20 is a flowchart showing another example of an attachment information collecting process.

FIG. 21 is a diagram showing another example of information stored in an internal memory of a controller.

FIG. 22 is a flowchart showing another example of a securing-of-attachment recognizing process.

DETAILED DESCRIPTION OF EXAMPLE EMBODIMENTS

Example embodiments will now be described with reference to the accompanying drawings, wherein like reference numerals designate corresponding or identical elements throughout the various drawings. The drawings are to be viewed in an orientation in which the reference numerals are viewed correctly.

The following description discusses example embodiments of the present invention with reference to the drawings as needed.

FIG. 1 is a side view of a working vehicle 1 according to the present example embodiment. In the present example embodiment, a backhoe, which is a swivel working vehicle, is discussed as an example of the working vehicle 1. Note, however, that the working vehicle 1 according to an example embodiment of the present invention is not limited to a backhoe, and may be, for example, some other construction machine or agricultural machine such as a compact track loader, a skid-steer loader, or a tractor.

The working vehicle 1 includes a machine body (swivel base) 2, a cabin 3, a working device 4, and traveling device(s) 5. The cabin 3 is provided on the machine body 2. The cabin 3 includes a seat 8, operation members (manual users) to be operated by an user seated on the seat 8, and/or the like. The manual operation members include a travel operator 6 to operate the traveling device 5 and a work operator 7 to operate the working device 4.

In the following description, for convenience, assuming the machine body 2 is oriented relative to the traveling device 5 as illustrated in FIG. 1, the direction in which the driver sitting on the seat 8 of the working vehicle 1 faces (direction of arrow A1 in FIG. 1) is referred to as “front”, and the opposite direction (direction of arrow A2 in FIG. 1) is referred to as “rear”. The left side of the driver (near side in FIG. 1) is referred to as “left side”, and the right side of the driver (far side in FIG. 1) is referred to as “right side”. A horizontal direction perpendicular to the front and back direction is referred to as the “width direction” of the machine body 2.

The traveling device 5 supports the machine body 2 to such that the machine body 2 is allowed to travel. The traveling device 5 includes a travel frame (truck frame) 5a and traveling mechanisms 5b. The travel frame 5a is a structure having the traveling mechanisms 5b attached thereto and supporting the machine body 2 at the top thereof.

The travel mechanisms 5b are provided on the left and right sides of the travel frame 5a. The travel mechanisms 5b are, for example, crawler travel mechanisms. The user operates the travel operator 6 to cause both the left and right travel mechanisms 5b to rotate in a forward direction, both the left and right travel mechanisms 5b to rotate in a reverse direction, only one of the left and right travel mechanisms 5b to rotate in the forward direction, or one of the left and right travel mechanisms 5b to rotate in the forward direction and the other to rotate in the reverse direction to cause the machine body 2 (working vehicle 1) to travel forward, rearward, or turn left or right. Note that the travel mechanisms 5b are not limited to crawler travel mechanisms, and may be tire travel mechanisms.

The machine body 2 is supported via a swivel bearing 2a on the traveling device 5 swivelably about a swivel axis 2b extending in the up and down direction. The machine body 2 is provided with a swivel motor to drive the machine body 2 to swivel (drive the machine body 2 to rotate) about the swivel axis 2b relative to the traveling device 5. The swivel motor includes a hydraulic motor (hydraulic actuator).

The working device 4 is attached to the machine body 2. The working device 4 includes an attachment 30, a linkage 50, and a position changer C. The attachment 30 is, for example, a working tool such as a bucket 30A, and is attachable to and detachable from the linkage 50. Examples of attachments 30 other than the bucket 30A include earth augers, asphalt cutters, angle brooms, crushers, grapple, grading beams, sweepers, snow blowers, pallet forks, breakers, mowers, rippers and the like. Attachments 30 of each type may have different specifications such as work content, structures, sizes and/or shapes.

The linkage 50 is provided on the position changer C to attach and detach an attachment 30 thereto and therefrom. The position changer C is provided on the machine body 2. The position changer C is operable to be driven to change the relative position of the linkage 50 relative to the machine body 2. The proximal portion of the position changer C is connected to the machine body 2, and the distal end (distal portion) of the position changer C is provided with the linkage 50. The position changer C is operable to, for example, raise and lower the linkage 50 to change the relative position between the linkage 50 and the machine body 2 to move the position of the attachment 30 connected to the linkage 50.

In the present example embodiment, the position changer C includes a boom 14 and an arm 15. The boom 14 is supported on the machine body 2 such that the boom 14 is swingable up and down. The arm 15 is swingably connected to the distal end (distal portion) of the boom 14. Specifically, the position changer C includes not only the boom 14 and the arm 15 but also a support 10, a boom cylinder 16, an arm cylinder 17, a link mechanism 18 and a bucket cylinder 19. The following details each feature of the position changer C.

The support 10 supports the boom 14 at the front portion of the machine body 2 such that the boom 14 is swingable up and down. The support 10 includes a support bracket 11, a swing bracket 12 and a swing cylinder 13. The support bracket 11 is provided such that the support bracket 11 projects forward from the machine body 2. The front portion of the support bracket 11 (the portion that projects from the machine body 2) has attached thereto the swing bracket 12 such that the swing bracket 12 is swingable about a vertical shaft (swing shaft(s)) 12a. The swinging movement of the swing bracket 12 is achieved by the extension and retraction of the swing cylinder 13. The swing cylinder 13 includes a first end rotatably connected to the swing bracket 12 via the shaft, and a second end rotatably connected to the machine body 2 via a shaft. Thus, in response to the operation of the work operator 7 by the driver of the working vehicle 1, the swing cylinder 13 extends or retracts, and the swing bracket 12 swings in the width direction (a horizontal direction centered on the swing shaft 12a). Accordingly, the boom 14 and the like supported by the swing bracket 12 swings in the width direction.

Note that the description about the present example embodiment discusses an example case in which the support 10 includes the swing bracket 12, but the support 10 need only support the boom 14 swingably at least up and down, and is not limited to the above mentioned example. That is, the support 10 may support the boom 14 swingably up and down and not swingably in the width direction.

The proximal portion of the boom 14 is supported by the support 10 swingably (pivotally) up and down. The proximal portion of the boom 14 is attached to the swing bracket 12 via a shaft 14a extending in the horizontal direction (width direction). A first end of the boom cylinder 16 is rotatably connected to the boom 14 via a shaft, and a second end of the boom cylinder 16 is rotatably connected via a shaft to the support 10. In response to the operation of the work operator 7 by the driver of the working vehicle 1, the boom cylinder 16 extends or retracts, and the boom 14 swings about the shaft 14a (about an axis in the horizontal direction).

The proximal portion of the arm 15 is attached to the distal portion of the boom 14 via a shaft 15a extending in the horizontal direction (width direction). A first end of the arm cylinder 17 is rotatably connected via a shaft to the arm 15, and a second end of the arm cylinder 17 is rotatably connected via a shaft to the boom 14. In response to the operation of the work operator 7 by the driver of the working vehicle 1, the arm cylinder 17 extends or retracts, and the arm 15 swings about the shaft 15a (about an axis in the horizontal direction).

The linkage 50 is swingably connected to the distal end portion (distal portion) of the arm 15. Specifically, the proximal portion of the linkage 50 is attached to the distal portion of the arm 15 via a shaft 15b (first attaching shaft) extending in the horizontal direction (width direction). The arm 15 is provided with a hydraulic fluid outlet port (power outlet port) 48a and a hydraulic fluid inlet port 48b.

The link mechanism 18 is located between the distal end portion (distal portion) of the arm 15 and the linkage 50. A first end of the link mechanism 18 is attached to the arm 15 via a shaft (second attaching shaft) 18a which extends in the horizontal direction (width direction) and which is located closer to the proximal portion of the arm 15 than the first attaching shaft 15b is. The linkage 50 is attached to a second end of the link mechanism 18 via a shaft (third attaching shaft) 18b extending in the horizontal direction (width direction).

A first end of the bucket cylinder 19 is rotatably connected via a shaft to the link mechanism 18, and a second end of the bucket cylinder 19 is rotatably connected via a shaft to the proximal portion of the arm 15. In response to the operation of the work operator 7 by the driver of the working vehicle 1, the bucket cylinder 19 extends or retracts, and the linkage 50 swings about the first attaching shaft 15b (about an axis in the horizontal direction).

Note that the above mentioned position changer C is an example, and that this does not imply any limitation. For example, in the case where the working vehicle 1 is a compact track loader, the position changer C is a device that includes arms, lift links, control links, arm cylinders, front cylinders, and/or the like, and, in the case where the working vehicle 1 is a tractor, the position changer C is a lifter including a three-point linkage, etc.

The following description details the linkage 50. The linkage 50 is, for example, a quick hitch (hitch) to attach and detach an attachment 30 thereto and therefrom. The quick hitch 50 is provided on a distal portion (distal end) of the arm 15. The quick hitch 50 is a linkage to easily attach and detach various attachments (hydraulic-driven working tools) 30 such as a bucket 30A. The user of the working vehicle 1 can easily change attachments 30 using the quick hitch 50. The quick hitch 50 is therefore also called “quick changer” or “quick coupler”. In the example shown in FIG. 1, the bucket 30A which is an example of the attachment 30 is attached to the quick hitch 50.

FIG. 2A is a side view illustrating the quick hitch 50 in a releasing state. FIG. 2B is a side view illustrating the quick hitch 50 in a locking state. The quick hitch 50 includes a bracket 51, a locking mechanism 52, a driver 53, and/or the like. The bracket 51 is connected to the arm 15 and the link mechanism 18, and defines at least the proximal portion of the quick hitch 50. The locking mechanism 52 is selectively operable in a locking state in which an attachment 30 is secured (locked) to the bracket 51 (to quick hitch 50) or a releasing state in which an attachment 30 is allowed to be detached from the bracket 51. The driver 53 is an actuator operable to actuate the locking mechanism 52 into the locking state or the releasing state. The driver 53 is, for example, a hydraulic cylinder (hitch cylinder) which is extendable and retractable, and actuates the locking mechanism 52 by extending or retracting. A first end of the hitch cylinder 53 is rotatably connected via a shaft to the bracket 51. A second end of the hitch cylinder 53 is rotatably connected via a shaft to the locking mechanism 52.

An attachment 30 is provided, at a proximal portion thereof, with a coupled portion 30a to be coupled to the quick hitch 50. In the present example embodiment, the coupled portion 30a includes a pair of shafts (mounting pins). The pair of mounting pins 30a are arranged such that each of them extends in the width direction at the proximal portion of the attachment 30. The pair of mounting pins 30a are separated from each other in a predetermined direction and extending in parallel to each other.

The quick hitch 50 includes a coupling portion 50a which engages with the pair of mounting pins 30a. The engagement between the coupling portion 50a and the pair of mounting pins 30a allows an attachment 30 to be held. The coupling portion 50a includes a first cutout 50al in the bracket 51 and a second cutout 50a2 in the locking mechanism 52.

The first cutout 50al is a cutout (recess) with which one (mounting pin 30a1) of the pair of mounting pins 30a can engage. The second cutout 50a2 is a cutout (recess) with which the other (mounting pin 30a2) of the pair of mounting pins 30a can engage. The first cutout 50al and the second cutout 50a2 have openings facing in the opposite directions (in directions away from each other). That is, the first cutout 50al and the second cutout 50a2 are recessed in directions approaching each other.

The locking mechanism 52 is attached to the bracket 51 such that the locking mechanism 52 is allowed to move toward and away from the bracket 51. In the present example embodiment, the second cutout 50a2 is in the distal end portion of the locking mechanism 52, and the proximal portion of the locking mechanism 52 is attached swingably about the axis of the third attaching shaft 18b. Thus, the locking mechanism 52 swings about the axis of the third attaching shaft 18b as the hitch cylinder 53 extends or retracts. Accordingly, it is possible to change the distance (first clearance) D1 between the first cutout 50al and the second cutout 50a2. Note that, in FIGS. 2A and 2B, the first clearance D1 is the shortest distance between the wall of the first cutout 50al and the wall of the second cutout 50a2.

When the hitch cylinder 53 retracts and the first clearance D1 reaches a distance less than the clearance (second clearance) D2 between the pair of mounting pins 30a, the first cutout 50al and the mounting pin 30al are disengaged from each other and the second cutout 50a2 and the mounting pin 30a2 are disengaged from each other, in the quick hitch 50. With this, the locking mechanism 52 enters a releasing state (also referred to as “unlock state”) in which the attachment 30 is not secured, and the attachment 30 is allowed to be detached from the quick hitch 50. Note that, in FIGS. 2A and 2B, the second clearance D2 is the shortest distance between the peripheral wall of the mounting pin 30al and the peripheral wall of the mounting pin 30a2.

On the other hand, when the hitch cylinder 53 extends such that the first clearance D1 is kept at the second clearance D2, the first cutout 50al and the mounting pin 30al are kept engaging with each other and the second cutout 50a2 and the mounting pin 30a2 are kept engaging with each other, in the quick hitch 50. It is noted here that, as the distance between the first cutout 50al and the second cutout 50a2 increases, the pair of mounting pins 30a are kept engaging with the cutouts 50al and 50a2. With this, the locking mechanism 52 enters a securing state (or locking state) (also referred to as “lock state”) in which the attachment 30 is secured, and the attachment 30 is attached to the quick hitch 50.

Note that, in the present example embodiment, the locking mechanism 52 is swingably attached to the bracket 51, but is not limited to the above mentioned configuration. For example, the following configuration may be used: the locking mechanism 52 is attached to the bracket 51 such that the locking mechanism 52 is slidable toward and away from the bracket 51, and the locking mechanism 52 slides as the hitch cylinder 53 extends or retracts.

In the present example embodiment, the first cutout 50al and the second cutout 50a2 have their openings facing away from each other, but the openings may face in the directions approaching each other. In such a case, as the hitch cylinder 53 retracts to allow the pair of mounting pins 30a to be inserted in the first cutout 50al and the second cutout 50a2 to maintain the engagement between the mounting pins 30a and the cutouts 50al and 50a2, the locking mechanism 52 enters the locking state. As the hitch cylinder 53 extends, the pins and cutouts are disengaged and the locking mechanism 52 enters the releasing state.

The quick hitch 50 need only be able to attach and detach the attachment 30 thereto and therefrom, and is not limited to the above mentioned configuration. For example, in the case where the attachment 30 has a through-hole, the quick hitch 50 may be configured such that, when a latch pin is inserted into the through hole as the hitch cylinder 53 is driven, the quick hitch 50 keeps the attachment 30 connected thereto, and that when the latch pin is removed from the through-hole as the hitch cylinder 53 is driven, the quick hitch 50 disconnects the attachment 30 therefrom.

The bucket 30A attached to the quick hitch 50 as shown in FIG. 1 is detached from the quick hitch 50, and another attachment 30 is attached to the quick hitch 50. With this, it is possible to perform various types of work other than excavation (or other excavation work) via the other attachments 30.

FIG. 3 is a block diagram of an attachment usage system 100 and the working vehicle 1 according to the present example embodiment. The attachment usage system 100 includes the working vehicle(s) 1 and attachment(s) 30. The example in FIG. 3 includes one working vehicle 1 and two attachments 30, but the number of working vehicles 1 and the number of attachments 30 included in the attachment usage system 100 may be selected appropriately.

The working vehicle 1 includes a controller 21, a storing device (memory and/or storage) 22, a receiver 23, a communicator 24, a user interface (indicated as “UI” in FIG. 3) 25, a battery 20, switches (each indicated as “SW” in FIGS. 3) 26, 28, and 29, and/or the like.

The controller 21 may include a processing circuit that includes one or more processors. The controller 21 is configured or programmed to control the working vehicle 1 and performs various controls relating to the working vehicle 1. The controller 21 is communicably connected to a plurality of devices in or on the working vehicle 1 via in-vehicle network(s) such as CAN, ISOBUS, LIN, FlexRay and/or the like.

The controller 21 may include one or more memories, various kinds of analog circuits, various kinds of digital circuits, and/or the like. The one or more memories contain (store) software program(s) to be executed by one or more processors and various data. Specifically, among the one or more memories included in the controller 21, a memory 21a (internal memory) includes a volatile or nonvolatile memory. The controller 21 uses, for example, a predetermined storage area of the memory 21a including a volatile memory as a buffer for temporary storage of information and data.

The controller 21 is communicably connected to the storing device 22 (nonvolatile memory), and the storing device 22 is provided externally to the controller 21. The memory 21a and the storing device 22 store software program(s) and control data for the controller 21 to control the operation of each element. The storing device 22 stores pieces of control data corresponding to various types of attachments 30.

The controller 21 is configured or programmed to read the software program(s) and control data from the storing device 22 and perform various processes based on the software program(s) and the control data, via one or more processors. Note that the controller 21 may be configured or programmed to also perform various processes based on predetermined logic circuit(s) via one or more processors.

Examples of the processors include central processing unit (CPU), graphics processing unit (GPU), digital signal processor (DSP), field programmable gate array (FPGA), and application specific integrated circuit (ASIC).

Note that the controller 21 may include a plurality of physically separated processors cooperating to perform various processes, and the structure thereof is not limited to those described above. In such a case, the plurality of processors are provided in or on respective one or more computers physically separated from the working vehicle 1, and are communicably connected to each other via a network such as an in-vehicle network, LAN, WAN, and/or the Internet.

The software program(s) may be stored in recording medium (media) (nonvolatile memory (memories) such as HDD, SSD, CD-ROM, and/or DVD-ROM) communicably connected to the controller 21 and/or external server device(s) connected to the controller 21 via a network, and may be installed from the medium, the server device, and/or the like into the memory.

The receiver 23 is a device to receive wireless signals Q1 compliant with a near field communication standard. Specifically, the receiver 23 is a beacon scanner to receive wireless signals Q1 (beacon signals) compliant with Bluetooth (registered trademark) Low Energy which is a near field communication standard. The beacon scanner 23 measures the received signal strength indicator (RSSI, received signal strength) of the received wireless signals Q1. Note that RSSI may be hereinafter simply referred to as received signal strength. The beacon scanner 23 is provided in or on the machine body 2.

The communicator 24 communicates with a portable device 70 via the Internet or wireless LAN. The portable device 70 is a smartphone, a tablet computer, and/or the like. The user interface 25 includes, for example, a touchscreen (touch panel) and/or the like. For another example, the user interface 25 may include an input and an output provided independently of each other.

The battery 20 supplies electricity to electric equipment in and/or on the working vehicle 1. The operation actuator (attaching/detaching switch) 26, the auxiliary mode switch 28, and the auxiliary output switch 29 are respective operation switches to be operated by the user of the working vehicle 1. The operation actuator 26 is a momentary operation switch. The user interface 25 and the switches 26, 28, and 29 are provided operably in the vicinity of the seat 8 in the cabin 3.

The operation actuator 26 is operated to attach an attachment 30 to the quick hitch 50 or allow the attachment 30 to be detached from the quick hitch 50. The auxiliary mode switch 28 is operated to start an auxiliary mode in which specific attachment(s) 30 are usable. The auxiliary output switch (third operation switch) 29 is operated to supply (transmit) hydraulic fluid as power to the hydraulic fluid outlet port 48a.

Note that the description about the present example embodiment discusses cases in which the working vehicle 1 includes a single operation actuator 26 as a switch to be used to attach and detach an attachment 30 (allow an attachment 30 to be detached) to and from the quick hitch 50. Note, however, that the working vehicle 1 may include individual operation switches to receive an operation to attach the attachment 30 to the quick hitch 50 and to receive an operation to detach the attachment 30 (allow an attachment 30 to be detached) from the quick hitch 50. In such a case, the working vehicle 1 includes an attaching switch to be operated to attach the attachment 30 to the quick hitch 50, and a detaching switch to be operated to allow the attachment 30 to be detached from the quick hitch 50.

The switches 26, 28, and 29, the travel operator 6, the work operator 7 and the like are not limited to hardware operation switches, operating levers and the like, and, for example, may be software keys and the like on the display screen of the user interface 25.

The working vehicle 1 includes, as hydraulic-related features, a main pump P1, a pilot pump P2, a control valve unit (indicated as “CVU” in FIG. 3) 40, a proportional valve 41, a regulator 42, sensors 43 and 44, hydraulic actuators 13, 16, 17, 19, 46L, 46R, and 53, fluid passage(s), a tank, and/or the like. The main pump P1 and the pilot pump P2 are driven by power from a prime mover 9 to deliver hydraulic fluid sucked from the tank to fluid passage(s). The prime mover 9 includes, for example, an engine. For another example, the prime mover 9 may include an electric motor.

The main pump P1 is a variable displacement hydraulic pump. The regulator 42 changes the angle of the swash plate of the main pump P1. The controller 21 controls the opening of the proportional valve 41 to apply pilot pressure, which is the hydraulic pressure of hydraulic fluid delivered by the pilot pump P2, to the regulator 42. The controller 21 then actuates the regulator 42 to change the angle of the swash plate of the main pump P1 to change the amount of hydraulic fluid delivered by the main pump P1. Operating equipment 47 includes the travel operator 6 and work operator 7, operating valves corresponding to the travel operator 6 and the work operator 7, switching valve(s), and the like.

The control valve unit 40 allows hydraulic fluid supplied from the main pump P1 through fluid passage(s) to flow to the swing cylinder 13, the arm cylinder 17, the boom cylinder 16, the bucket cylinder 19, and the hitch cylinder 53 of the working device 4 and the hydraulic fluid outlet port 48a. The control valve unit 40 also allows hydraulic fluid that flows from the swing cylinder 13, the arm cylinder 17, the boom cylinder 16, the bucket cylinder 19, and the hitch cylinder 53, and the hydraulic fluid inlet port 48b (return fluid) to be discharged. The control valve unit 40 controls the direction and amount of supply of hydraulic fluid to the swing cylinder 13, the arm cylinder 17, the boom cylinder 16, the bucket cylinder 19, and the hitch cylinder 53. The control valve unit 40 also controls the amount of supply of hydraulic fluid to the hydraulic fluid outlet port 48a.

Specifically, the control valve unit 40 includes control valves 40a, 40b, 40c, 40d, 40e, and 40f corresponding to the swing cylinder 13, the arm cylinder 17, the boom cylinder 16, the bucket cylinder 19, the hitch cylinder 53, and the ports 48a, 48b. Each of the control valves 40a to 40f is switchable between a neutral position, a first position, and a second position. At least the control valves 40e and 40f of the control valves 40a to 40f are electrically actuated. The control valves 40a to 40f are normally held in the neutral position by the elastic force of a spring.

The control valve unit 40 includes, in addition to the above mentioned control valves 40a to 40f, control valve(s) corresponding to a swivel motor and/or a dozer cylinder to drive a dozer, and/or the like (detailed description is not provided here).

The operating valve(s) of the operating equipment 47 and/or the like that correspond to the work operator 7 are actuated according to the manner in which the work operator 7 is operated, thus allowing the pilot pressure of pilot fluid from the pilot pump P2 to act on pressure receiver(s) of the control valve(s) 40a to 40d. For example, the work operator 7 may be supported on operating valves of the operating equipment 47 and the operating valves may be physically actuated by operation of the work operator 7. Additionally or alternatively, a detection sensor to detect the amount (degree) and direction of operation of the work operator 7 may be provided and the controller 21 may electrically actuate the operating valve(s) based on the detection result from the detection sensor. With this, the control valve(s) 40a to 40d is/are switched from the neutral position to the first position or the second position, so that hydraulic fluid from the main pump P1 is supplied through the control valve(s) 40a to 40d to the swing cylinder 13, the arm cylinder 17, the boom cylinder 16, and/or the bucket cylinder 19 to cause the swing cylinder 13, the arm cylinder 17, the boom cylinder 16, and/or the bucket cylinder 19 to extend or retract. It follows that the boom 14 and/or the attachment 30 such as the bucket 30A attached to the quick hitch 50 swing.

While the operation actuator 26 is operated for a first predetermined period of time T1 or more while the locking mechanism 52 is in the releasing state, the controller 21 places the control valve 40e in the first position to allow hydraulic fluid from the main pump P1 to be supplied to the hitch cylinder 53 in the first direction to cause the hitch cylinder 53 to extend. Accordingly, the operation of the operation actuator 26 that lasts for a first predetermined period of time T1 or more while the locking mechanism 52 is in the releasing state causes the hitch cylinder 53 to extend to the predetermined degree or more, bringing the locking mechanism 52 into the locking state. Note that, even if the operation actuator 26 is operated while the locking mechanism 52 is in the releasing state, provided that the operation only lasts for a period less than the first predetermined period of time T1, the controller 21 does not place the control valve 40d in the first position and therefore the locking mechanism 52 does not enter the locking state.

On the contrary, when the operation actuator 26 is operated for a second predetermined period of time T2 or more while the locking mechanism 52 is in the locking state, the controller 21 places the control valve 40e in the second position to allow hydraulic fluid from the main pump P1 to be supplied to the hitch cylinder 53 in a second direction opposite to the first direction to cause the hitch cylinder 53 to retract. Accordingly, the operation of the operation actuator 26 that lasts for a second predetermined period of time T2 or more while the locking mechanism 52 is in the locking state causes the hitch cylinder 53 to retract to a predetermined degree or more, bringing the locking mechanism 52 into the releasing state.

The first predetermined period of time T1 and the second predetermined period of time T2 are each, for example, about 2 to 3 seconds. The first predetermined period of time T1 and the second predetermined period of time T2 may be the same period or different periods. The specific values of the first predetermined period of time T1 and the second predetermined period of time T2 are examples, and not limited to the values above. The same applies to a third predetermined period of time T3 and a period of time T4 (described later).

When the auxiliary mode switch 28 is operated and the auxiliary mode is selected, a specific attachment 30 is attached to the quick hitch 50. The hydraulic fluid outlet port 48a and a hydraulic fluid inlet port 38b of the specific attachment 30B are connected together by a hose, and the hydraulic fluid inlet port 48b and a hydraulic fluid outlet port 38a of the specific attachment 30B are connected together by a hose.

Upon operation of the auxiliary output switch 29 under such circumstances, the controller 21 switches the control valve 40f from the neutral position to the first position or the second position. With this, hydraulic fluid from the main pump P1 is supplied (transmitted) through a fluid passage 45a to the hydraulic fluid outlet port 48a, and hydraulic fluid flowing into a fluid passage 45b from the hydraulic fluid inlet port 48b is drained through the control valve unit 40.

With this, hydraulic fluid discharged through the hydraulic fluid outlet port 48a is introduced into the specific attachment 30B through the hydraulic fluid inlet port 38b via a hose or the like. Furthermore, hydraulic fluid (return fluid) discharged through the hydraulic fluid outlet port 38a of the specific attachment 30B is introduced through the hydraulic fluid inlet port 48b via a hose or the like and is drained from the control valve unit 40. Since hydraulic fluid is introduced and discharged to and from the specific attachment 30B as such, hydraulic actuators 36 such as a hydraulic motor and/or hydraulic cylinder(s) of the attachment 30B are actuated, making it possible to perform work using the attachment 30B.

When allowing hydraulic fluid to be introduced and discharged to and from the specific attachment 30B, the controller 21 changes the opening of the control valve 40f depending on what specific attachment 30 is attached to the quick hitch 50, to adjust the flow rate or hydraulic pressure of hydraulic fluid supplied to the hydraulic fluid outlet port 48a. For example, the controller 21 may cause the flow rate sensor 43 to detect the flow rate of hydraulic fluid flowing through the fluid passage 45a and control the opening of the control valve 40f. Additionally or alternatively, the controller 21 may cause the pressure sensor 44 to detect the hydraulic pressure of hydraulic pressure flowing through the fluid passage 45a and control the opening of the control valve 40f.

The traveling device 5 includes a pair of left and right travel motors (hydraulic motors) 46L and 46R corresponding to the pair of left and right traveling mechanisms 5b.

The control valve unit 40 allows hydraulic fluid supplied from the main pump P1 through fluid passage(s) to flow toward the travel motors 46L and 46R of the traveling device 5. The control valve unit 40 allows hydraulic fluid flowing from the travel motors 46L and 46R (return fluid) to be discharged. The control valve unit 40 controls the direction and amount of hydraulic fluid supplied to the travel motors 46L and 46R.

Specifically, the control valve unit 40 includes control valves 40g and 40h corresponding to the travel motor 46L and 46R. Each of the control valves 40g and 40h is switchable between a neutral position, a first position, and a second position. Each of the control valves 40g and 40h is normally held in the neutral position by the elastic force of a spring.

The operating valve(s) of the operating equipment 47 and/or the like that correspond to the travel operator 6 are actuated according to the manner in which the travel operator 6 is operated, thus allowing the pilot pressure of pilot fluid from the pilot pump P2 to act on pressure receiver(s) of the control valve(s) 40g and/or 40h. For example, the travel operator 6 may be supported on the operating valves of the operating equipment 47 and the operating valves may be physically actuated by operation of the travel operator 6. Additionally or alternatively, a detection sensor to detect the amount (degree) and direction of operation of the travel operator 6 may be provided and the controller 21 may electrically actuate the operating valve(s) based on the detection result from the detection sensor. This controls the supply, the stopping of supply, and the direction of supply of hydraulic fluid from the control valve(s) 40g and/or 40h to the travel motor(s) 46L and/or 46R, the travel motor(s) 46L and/or 46R rotate(s) in the forward direction, rotate in the reverse direction, or stop, the left and/or right travel mechanism(s) 5b also rotate(s) in the forward direction, rotate in the reverse direction, or stop, and the working vehicle 1 travels forward, rearward, turn left or right, or stops.

Furthermore, switching valve(s) for speed changes of the operating equipment 47 and/or like switch(es) positions according to control signal(s) from the controller 21, so that the rotation speed of the travel motor(s) 46L and/or 46R increases or decreases and that the travel speed of the travel mechanisms 5b and the working vehicle 1 is changed.

The attachment 30 attachable to the working vehicle 1 is provided with a transmitter 33. The transmitter 33 is a beacon transmitter 33 to periodically transmit a wireless signal Q1 compliant with a near field communication standard. Specifically, the beacon transmitter 33 is a device to periodically transmit an advertisement signal (also called “advertisement packet” or “beacon signal”) which is a wireless signal Q1 compliant with Bluetooth (registered trademark) Low Energy. The beacon transmitter 33 looks like a small tag, and is therefore sometimes called a “BLE tag”. The beacon transmitter 33 includes a microcomputer, a memory, a transmitter circuit, a battery, a vibration sensor 34, and/or the like. The elements of the beacon transmitter 33 are driven by electricity from the battery. The beacon transmitter 33 transmits the advertisement signal Q1 at interval(s) of, for example, about 1 second to about 3 seconds, but the intervals are not limited to 1 second to 3 seconds and may be selected as appropriate.

FIG. 4 shows an example of information contained in an advertisement signal Q1 transmitted from the beacon transmitter 33. The advertisement signal Q1 includes a header, a beacon ID (tag serial number), an attachment ID, and other information.

The beacon ID is identification information of the beacon transmitter 33 which is the sender of the advertisement signal Q1. The attachment ID is identification information of the attachment 30 in or on which the beacon transmitter 33 which is the sender of the advertisement signal Q1 is provided.

The other information in the advertisement signal Q1 includes vibration information relating to the vibration state detected by the vibration sensor 34 of the beacon transmitter 33 which is the sender, i.e., vibration information relating to the vibration state of the attachment 30 in or on which the beacon transmitter 33 is provided. The vibration information may include information such as a message indicating whether or not the attachment 30 is vibrating (presence or absence of vibration). The vibration information may include, instead of or in addition to the information such as a message, a vibration indicator (numerical value) indicating the magnitude of vibration detected by the vibration sensor 34. The vibration indicator may be, for example, at least one of the displacement, velocity, or acceleration of vibrations of the attachment 30 detected by the vibration sensor 34. Inertial sensor(s) such as an acceleration sensor and/or a gyroscope sensor may be used as the vibration sensor 34.

Note that examples of other information included in the advertisement signal Q1, other than the vibration information, include the supply amount and the supply pressure of hydraulic fluid to the attachment 30, the name (official name) of the attachment 30, the remaining battery level of the beacon transmitter 33, and the acting time (hour meter) of the attachment 30 having the beacon transmitter 33 attached thereto.

As illustrated in FIG. 1, the beacon transmitter 33 is located on, for example, a proximal portion of the attachment 30 that faces the machine body 2 of the working vehicle 1. The beacon scanner 23 is located at, for example, a front portion of the machine body 2. More specifically, as illustrated in FIG. 1, the beacon scanner 23 is located at an upper front portion of the machine body 2 (upper portion of the cabin 3). The controller 21 is provided in the machine body 2. Since the beacon scanner 23 is provided in or on the machine body 2, it is possible to achieve a configuration in which output signals from the beacon scanner 23 can be inputted into the controller 21 using simple electric wiring or simple communication circuit(s) as compared to cases where the beacon scanner 23 is provided on the movable working device 4.

The advertisement signal Q1 transmitted from the beacon transmitter 33 is received by the beacon scanner 23 of the working vehicle 1. The controller 21 identifies (recognizes) the attachment 30 based on the attachment ID included in the advertisement signal Q1 received by the beacon scanner 23. Specifically, the controller 21 selects, based on a selection condition varying depending on the relative position of the linkage (quick hitch) 50 relative to the machine body 2, a piece of identification information (attachment ID) included in a wireless signal (advertisement signal) Q1 with a received signal strength (RSSI) satisfying the selection condition. With this, the controller 21 identifies the attachment 30 attached to the quick hitch 50.

For example, the controller 21 acquires a first threshold which has a value that varies depending on the relative position. The selection condition includes a condition in which the identification information to be selected by the controller 21 is identification information included in a wireless signal Q1 with a received signal strength (RSSI) greater than the first threshold. The first threshold is a value corresponding to the relative position obtained when the advertisement signal Q1 is received. Note that in this case, the first threshold used to select identification information is not limited to the value that corresponds to the relative position at the point in time when the beacon scanner 23 receives the advertisement signal Q1, and may be the value that corresponds to the relative position before or after the point in time of the receipt of the advertisement signal Q1 by the beacon scanner 23.

In the case where the relative distance between the machine body 2 or the receiver 23 and the linkage 50 is a first distance, the controller 21 acquires the first threshold having a value less than when the relative distance is a second distance which is shorter than the first distance. The relative distance is the distance between the machine body 2 or the receiver 23 and the linkage 50, and is preferably the distance between the receiver 23 and the linkage 50. Note that the relative distance is not limited to the distance between the receiver 23 and the linkage 50, and may be the distance between a predetermined reference position on the machine body 2 and the linkage 50.

FIG. 5 is a graph showing the relationship between the first threshold and the relative distance. As shown in FIG. 5, the first threshold is defined to decrease in value as the relative distance increases. The first threshold is defined to increase in value as the relative distance decreases. In the present example embodiment, as shown in FIG. 5, there is a proportional relationship or a relationship close to a proportional relationship (first correlation) between the first threshold and the relative distance. Thus, the function representing the relationship between the first threshold and the relative distance is defined to form a straight line or a substantially straight line.

Note that the first threshold does not need to be proportional to the relative distance, and that the function representing the relationship between the first threshold and the relative distance may, for example, be defined to form a curve. That is, the first threshold may be defined to sharply decrease after gradually decreasing as the relative distance increases, and may be defined to gradually decrease after sharply decreasing as the relative distance increases.

The controller 21 acquires the first threshold based on the posture of the boom 14 and the posture of the arm 15. In the present example embodiment, the working vehicle 1 includes a posture detector 49 to detect the posture of the boom 14 (boom posture) relative to the machine body 2 and the posture of the arm 15 (arm posture) relative to the boom 14. The posture detector 49 is a sensor provided in/on the working vehicle 1, and is operable to detect the boom posture and the arm posture. The controller 21 is configured or programmed to calculate at least the boom posture and the arm posture based on the signal detected by the posture detector 49.

The boom posture is the angle of swing (angle in up-and-down direction, first swing angle) of the boom 14 relative to the machine body 2. In particular, since the boom 14 is attached to the support 10 (swing bracket 12), the first swing angle is the swing angle of the boom 14 relative to the swing bracket 12. The arm posture is the swing angle (angle in up-and-down direction, second swing angle) of the arm 15 relative to the boom 14.

In the present example embodiment, since the quick hitch 50 is swingably attached to the arm 15 and the swing bracket 12 is swingably attached to the support bracket 11, the posture detector 49 may be operable to detect the posture of elements of the position changer C (such as the quick hitch 50, the swing bracket 12 and/or the like) in addition to the boom posture and the arm posture. That is, the posture detector 49 may be operable to detect the posture of the swing bracket 12 (swing posture) relative to the support bracket 11 and/or the posture of the quick hitch 50 (hitch posture) relative to the arm 15.

In such a case, the swing posture is the swing angle of the swing bracket 12 (angle in the horizontal direction, third swing angle) relative to the support bracket 11. The hitch posture is the swing angle of the quick hitch 50 (angle in up-and-down direction, fourth swing angle) relative to the arm 15.

Note that the posture detector 49 need only be operable to detect at least the first swing angle and the second swing angle, and may be operable to further detect swing angle(s) other than the third swing angle and the fourth swing angle. In the case where the quick hitch 50 includes a rotating mechanism and/or a swing mechanism to change the posture of the attachment 30, the posture detector 49 may be operable to detect the angle of rotation of the rotating mechanism and/or the swing angle of the swing mechanism.

The posture detector 49 includes a rotation sensor to detect each swing angle (rotational position) of the position changer C. The posture detector 49 includes a first rotation sensor to detect the first swing angle, a second rotation sensor to detect the second swing angle, a third rotation sensor to detect the third swing angle, and a fourth rotation sensor to detect the fourth swing angle. Thus, once the controller 21 has calculated swing angles from signals detected by the rotation sensors, the controller 21 can calculate postures (swing posture, boom posture, arm posture, hitch posture) based on such swing angles and on arithmetic expression(s) stored in advance in the storing device 22.

Note that examples of the sensors included in the posture detector 49 include a potentiometer, but this does not imply any limitation. The posture detector 49 may include some other angle sensor(s), inertial sensor(s) such as an acceleration sensor and a gyroscope sensor, and/or the like. The posture detector 49 may include sensor(s) that is stroke sensor(s) to detect the stroke (degree of extension) of cylinder(s) (in the present example embodiment, the swing cylinder 13, the boom cylinder 16, the arm cylinder 17, the bucket cylinder 19). Furthermore, the posture detector 49 may include imager(s) (camera) to capture an image of the surrounding area of the working device 4, and the controller 21 may calculate posture(s) based on the image(s) captured by the imager.

After the controller 21 calculates the postures, the controller 21 corrects a predetermined first reference value based on the postures to obtain a first threshold. The first reference value is stored in advance in the storing device 22 and is defined for the cases where the relative distance is a predetermined reference distance.

The controller 21 corrects the first reference value based at least on the boom posture and the arm posture. Since the controller 21 can calculate the swing posture, the boom posture, the arm posture and the hitch posture, in the present example embodiment, the controller 21 corrects the first reference value based on such postures. Specifically, the controller 21 corrects the first reference value based on postures such that the first threshold and the relative distance satisfy the first correlation. For example, the controller 21 corrects the first reference value using a correction value (first correction value) which is based on the postures.

The controller 21 corrects the first reference value by multiplying the first reference value by the first correction value. In other words, the first correction value is a correction factor used to correct the first reference value.

Thus, in the case where the relative distance based on the postures is longer than the reference distance, the first correction value is less than 1. In the case where the relative distance based on the postures is equal to the reference distance, the first correction value is 1 and the first reference value is not substantially corrected. In the case where the relative distance based on the postures is shorter than the reference distance, the first correction value is greater than 1.

The first correction value is associated with the relative distance or the postures in a table (first correction table) and stored in a predetermined storage area of the storing device 22. The controller 21 acquires the first correction value from the postures and the first correction table. The controller 21 corrects the first reference value using the acquired first correction value to obtain the first threshold.

Note that the first correction values in the first correction table stored in the storing device 22 may be freely editable (changeable) by the driver using the user interface 25 and/or the portable device 70. The above description discusses example cases in which the controller 21 corrects the first reference value by multiplying the first reference value by the first correction value, but the method of correcting the first reference value using the first correction value is not limited to multiplying.

The above description discusses example cases in which the controller 21 acquires the first threshold by correcting the first reference value using the first correction value, but the first threshold may be associated with the relative distance or the postures in a table (first threshold table) and stored in a predetermined storage area of the storing device 22. In such a case, the controller 21 acquires the first threshold from the postures and the first threshold table.

The controller 21 may acquire a second threshold which has a value that varies depending on the relative position in addition to or instead of the first threshold. The selection condition may include a condition in which the identification information (attachment ID) to be selected by the controller 21 is identification information included in a wireless signal (advertisement signal) Q1 with a received signal strength (RSSI) equal to or lower than the second threshold. The second threshold is a value corresponding to the relative position obtained when an advertisement signal Q1 is received. In the case where the selection condition includes a condition in which the attachment ID to be selected by the controller 21 is an attachment ID included in an advertisement signal Q1 with an RSSI higher (greater) than the first threshold and equal to or lower (less) than the second threshold, the second threshold is defined to be greater than the first threshold.

Note that in this case, the second threshold to be used for the selection of identification information is, as with the case of the first threshold, not limited to the threshold corresponding to the relative position at the point in time when the beacon scanner 23 receives the advertisement signal Q1, and may be the threshold corresponding to the relative position before or after the point in time of the receipt of the advertisement signal Q1 by the beacon scanner 23.

In the case where the relative distance is a predetermined first distance, the controller 21 acquires the second threshold having a value less than when the relative distance is a predetermined second distance which is shorter than the first distance.

FIG. 6 is a graph showing the relationship between the second threshold and the corresponding relative distance. In FIG. 6, the second threshold is represented by solid line, and the first threshold is represented by dashed line for comparison with the second threshold. As shown in FIG. 6, the second threshold is defined to decrease in value as the relative distance increases. The second threshold is defined to increase in value as the relative distance decreases. In the present example embodiment, as shown in FIG. 6, there is a proportional relationship or a relationship close to a proportional relationship (second correlation) between the second threshold and the relative distance. Thus, the function representing the relationship between the second threshold and the relative distance is defined to form a straight line or a substantially straight line.

Note that the second threshold does not need to be proportional to the relative distance, and the function representing the relationship between the second threshold and the relative distance may be, for example, defined to form a curve. That is, the second threshold may be defined to sharply decrease after gradually decreasing as the relative distance increases, and may be defined to gradually decrease after sharply decreasing as the relative distance increases. In the case where the controller 21 selects identification information based on both the first threshold and the second threshold, it is preferable that the amount of change in the second threshold relative to an increase or decrease in the relative distance be the same as the amount of change in the first threshold relative to an increase or decrease in the relative distance.

The controller 21 acquires the second threshold based on the boom posture and the arm posture. Since the controller 21 can calculate other postures (swing posture and hitch posture) in addition to the boom posture and the arm posture, in the present example embodiment, the controller 21 acquires the second threshold based on such postures.

After the controller 21 calculates the postures, the controller 21 acquires the second threshold by correcting a predetermined second reference value based on the postures. The second reference value is stored in advance in the storing device 22 and is defined for the cases where the relative distance is a predetermined reference distance.

The controller 21 corrects the second reference value based at least on the boom posture and the arm posture. Since the controller 21 can calculate the swing posture, the boom posture, the arm posture and the hitch posture, in the present example embodiment, the controller 21 corrects the second reference value based on such postures. Specifically, the controller 21 corrects the second reference value based on the postures such that the second threshold and the relative distance satisfy the second correlation. For example, the controller 21 corrects the second reference value using the correction value (second correction value) which is based on the postures.

The controller 21 corrects the second reference value by multiplying the second reference value by the second correction value. In other words, the second correction value is a correction factor used to correct the second reference value.

Thus, in the case where the relative distance based on the postures is longer than the reference distance, the second correction value is less than 1. In the case where the relative distance based on the postures is equal to the reference distance, the second correction value is 1 and the second reference value is not substantially corrected. In the case where the relative distance based on the postures is shorter than the reference distance, the second correction value is greater than 1.

The second correction value is associated with the relative distance or the postures in a table (second correction table) and stored in a predetermined storage area of the storing device 22. The controller 21 acquires the second correction value from the postures and the second correction table. The controller 21 corrects the second reference value using the acquired second correction value to obtain the second threshold.

Note that the second correction values in the second correction table stored in the storing device 22 may be freely editable (changeable) by the driver using the user interface 25 and/or the portable device 70. The above description discusses example cases in which the controller 21 corrects the second reference value by multiplying the second reference value by the second correction value, but the method of correcting the second reference value using the second correction value is not limited to multiplying.

The above description discusses example cases in which the controller 21 acquires the second threshold by correcting the second reference value using the second correction value, but the second threshold may be associated with the relative distance or the postures in a table (second threshold table) and stored in a predetermined storage area of the storing device 22. The controller 21 acquires the second threshold from the postures and the second threshold table.

The following discusses example cases in which the controller 21 acquires the first threshold and the second threshold, the selection condition includes a condition in which identification information (attachment ID) to be selected by the controller 21 is identification information (attachment ID) included in a wireless signal (advertisement signal) Q1 with a received signal strength (RSSI) higher than the first threshold and equal to or lower than the second threshold. Note that detailed descriptions are not provided for the cases where the selection condition used by the controller 21 only relates to the first threshold and the cases where the selection condition used by the controller 21 only relates to the second threshold, because the only difference is the criterion based on which to determine whether the RSSI satisfies the selection condition.

In the case where one or more attachments 30 are present in the vicinity of the working vehicle 1, one or more advertisement signals Q1 from one or more beacon transmitters 33 of the one or more attachments 30 are received by the beacon scanner 23. Upon receipt of each advertisement signal Q1, the beacon scanner 23 measures the RSSI of the advertisement signal Q1.

The controller 21 reads the one or more attachment IDs from the one or more advertisement signals Q1 received by the beacon scanner 23. The controller 21 then, if the RSSI satisfies the selection condition, cause the internal memory 21a to store the attachment ID read from the advertisement signal Q1 and the RSSI such that the attachment ID and the RSSI are associated with each other for a period of time T4, so that attachment IDs and the RSSI are collected in the internal memory 21a. That is, the controller 21 acquires the first threshold and the second threshold based on the postures detected by the posture detector 49, and, if the RSSI is greater than the first threshold and less than or equal to the second threshold, causes the internal memory 21a to store the attachment ID and the RSSI.

Upon attachment of an attachment 30 to the quick hitch 50, the controller 21 selects, based on the RSSI(s), the attachment ID of the attachment 30 attached to the quick hitch 50 from the attachment ID(s) stored in the internal memory 21a. Specifically, the controller 21 selects an attachment ID corresponding to the highest RSSI from the attachment ID(s) stored in the memory 21a. The controller 21 then identifies the specifications and/or the like of the attachment 30 attached to the quick hitch 50 based on the selected attachment ID, and starts a predetermined process according to the attachment ID.

An example of the predetermined process is a process in which the controller 21 causes the user interface 25 to output (display) information indicating that the attachment 30 corresponding to the selected attachment ID is attached to the quick hitch 50 (working vehicle 1). Another example of the predetermined process is a process in which the controller 21 controls output of hydraulic fluid (power) to the attachment 30 attached to the quick hitch 50 (controls start and stop of the supply of hydraulic fluid to the attachment 30) according to the selected attachment ID. It is noted here that the controller 21 may also control at least one of the introduction of hydraulic fluid from the attachment 30, the amount of hydraulic fluid supplied to the attachment 30, or the pressure of hydraulic fluid supplied to the attachment 30.

With the attachment usage system 100, an automatic selection mode or a manual selection mode can be selected by, for example, an administrator performing a predetermined operation on the user interface 25. The automatic selection mode is a mode in which the controller 21 selects the attachment ID of the attachment 30 attached to the quick hitch 50 from the attachment ID(s) stored in the internal memory 21a and starts a predetermined process according to the selected attachment ID. In the automatic selection mode, the controller 21 identifies the attachment 30 attached to the quick hitch 50 based on the attachment ID selected based on a predetermined condition from the attachment ID(s) stored in the internal memory 21a.

The manual selection mode is a mode in which the controller 21 starts a predetermined process according to information relating to the attachment 30 received via the user interface 25. That is, in the manual selection mode, for example, the user of the working vehicle 1 inputs information relating to the attachment 30 attached to the quick hitch 50 via the user interface 25. In the manual selection mode, the controller 21 identifies the attachment 30 attached to the quick hitch 50 based on the information relating to the attachment 30 inputted via the user interface 25. The administrator uses the user interface 25 to place the working vehicle 1 in the automatic selection mode or the manual selection mode according to the demand of the user of the working vehicle 1 or the like.

Display data and control data are pre-set for each of the attachment IDs of attachments 30 attachable to the quick hitch 50, i.e., attachments 30 which can be used with the working vehicle 1.

FIG. 7 is a table showing an example of the relationship between the attachment IDs of the attachments 30 attachable to the quick hitch 50 and pieces of display data corresponding to the attachments 30. A piece of display data is data based on which the user interface 25 displays information about a corresponding attachment 30. The display data includes, for example, an icon, name, and specifications of the corresponding attachment 30. Such an attachment ID and display data of the attachment 30 are stored in a predetermined storage area of the storing device 22 such that the attachment ID and the display data of the attachment 30 are associated with each other. Note that display data other than that described above may be stored in the storing device 22 such that the display data is associated with the attachment ID.

FIG. 8 is a table showing an example of the relationship between the attachment IDs of the attachments 30 attachable to the quick hitch 50 and pieces of control data corresponding to the attachments 30. A piece of control data indicates control performed by the working vehicle 1 according to what attachment 30 is used. The control data includes, for example, the level of the amount of hydraulic fluid supplied to the corresponding attachment 30. Such an attachment ID and control data of the attachment 30 are stored in a predetermined storage area of the storing device 22 such that the attachment ID and the control data of the attachment 30 are associated with each other. Note that other control data, such as the level of hydraulic pressure outputted to the attachment 30 and/or the output value of power other than hydraulic fluid, may be stored in the storing device 22 such that the control data is associated with the attachment ID.

FIG. 9 is a flowchart showing an example of an attachment information collecting process. The attachment information collecting process is performed by the controller 21 of the working vehicle 1 based on software program(s) stored in the internal memory 21a or the storing device 22. The same applies to a securing-of-attachment recognizing process and a release-of-attachment recognizing process (described later). In FIG. 9, the advertisement signal Q1 is referred to as “ADV signal” and the attachment is referred to as “ATT” for convenience of description. The same applies to FIGS. 11, 14, 15, 17, 18, 20, and 22 (described later).

In the case where the automatic selection mode is selected (S1 in FIG. 9), upon receipt of an advertisement signal Q1 from the beacon transmitter 33 by the beacon scanner 23 (S2), the controller 21 acquires the attachment ID and RSSI of the advertisement signal Q1 from the beacon scanner 23 (S3).

Next, in the case where the acquired RSSI satisfies the selection condition (YES at S4), the controller 21 reads information included in the received advertisement signal Q1 (S5). Specifically, the controller 21 calculates postures from the signal(s) detected by posture detector 49, and acquires the first threshold and the second threshold (which are for use in the selection condition) based on the calculated postures. Then, in the case where the controller 21 determines that the acquired RSSI is greater than the first threshold and equal to or less than the second threshold and that the RSSI satisfies the selection condition, the controller 21 reads the information included in the received advertisement signal Q1.

Next, if the information read from the advertisement signal Q1 includes vibration information indicating that the attachment 30 is vibrating, the controller 21 determines that there is vibration on the attachment 30 (YES in S6). Alternatively, if the information read from the advertisement signal Q1 includes a vibration indicator and the vibration indicator is greater than a predetermined value (second predetermined value) Y, the controller 21 determines that there is vibration on the attachment 30 (YES in S6).

Next, the controller 21 causes the internal memory 21a to store the attachment ID included in the received advertisement signal Q1 and the RSSI of the advertisement signal Q1 such that the attachment ID and the RSSI are associated with each other (S7). It is noted here that the controller 21 causes the internal memory 21a to also store, for example, information relating to the time at which the attachment ID and the RSSI were stored (such as a timestamp) such that the information is associated with the attachment ID and the RSSI. The controller 21 may cause the internal memory 21a to also store, for example, a beacon ID and/or other information included in the received advertisement signal Q1 such that the beacon ID and/or the other information are associated with the attachment ID and the RSSI.

In contrast, if the RSSI of the received advertisement signal Q1 does not satisfy the selection condition (NO in S4), the controller 21 does not cause the internal memory 21a to store the attachment ID included in the received advertisement signal Q1 or the RSSI of the advertisement signal Q1. That is, in the present example embodiment, the controller 21 does not cause the internal memory 21a to store the attachment ID included in the received advertisement signal Q1 or the RSSI of the advertisement signal Q1 if the acquired RSSI is less than or equal to the first threshold or greater than the second threshold and does not satisfy the selection condition. Also if the received advertisement signal Q1 does not include vibration information indicating that the attachment 30 is vibrating (or the vibration indicator greater than the predetermined value Y) and it is determined that there is no vibration on the attachment 30 (NO in S6), the controller 21 does not cause the internal memory 21a to store the attachment ID included in the received advertisement signal Q1 or the RSSI of the advertisement signal Q1.

If any of the attachment ID(s) or RSSI(s) in the internal memory 21a has been stored for the period of time T4 or more (YES in S8), the controller 21 deletes that attachment ID(s) and RSSI(s) from the internal memory 21a (S9). It is noted here that the controller 21 also deletes, from the internal memory 21a, other information (such as time information) corresponding to the attachment ID(s) having been stored for the period of time T4 or more. The period of time T4 is, for example, about 30 seconds which corresponds to at least one of the time for an attachment 30 to be attached to the working vehicle 1 or the time for the attachment 30 to be replaced with another one. After step S9, the controller 21 repeats step S1 and subsequent steps.

FIG. 10 shows information stored in the internal memory 21a of the controller 21. The controller 21 repeats the attachment information collecting process shown in FIG. 9, so that attachment IDs and their corresponding RSSIs are collected in the internal memory 21a as shown in FIG. 10.

Specifically, the controller 21 selects one of the advertisement signal(s) Q1 that is received by the beacon scanner 23 from the beacon transmitter 33 on the attachment 30 which is located close to some extent to the quick hitch 50 having been changed in its relative position relative to the machine body 2 by the position changer C and which has vibrated when attached to the quick hitch 50. The attachment ID included in the selected advertisement signal Q1 and the RSSI of that advertisement signal Q1 are stored (collected) in the internal memory 21a of the controller 21 for the period of time T4. For another example, the controller 21 may cause the storing device 22 to store the attachment ID and the RSSI of the advertisement signal Q1 for the period of time T4.

In the case where an attachment 30 located on the ground or the like is to be attached to the working vehicle 1, the driver of the working vehicle 1 operates the traveling device 5 and the working device 4 using the operators 6 and 7 to, as shown in FIG. 2A, insert the bracket 51 and the locking mechanism 52 of the quick hitch 50 which is in the releasing state into the gap between the pair of mounting pins 30a to allow one of the mounting pins 30a to engage with the first cutout 50al of the bracket 51. Under such circumstances, when the driver operates the operation actuator 26 for a first predetermined period of time T1 or more, the controller 21 causes the hitch cylinder 53 to extend, and, as the locking mechanism 52 is moved by the hitch cylinder 53 in a direction away from the bracket 51, the first clearance D1 is maintained at the second clearance D2. This results in a state in which the other mounting pin 30a engages with the second cutout 50a2 of the locking mechanism 52, and the attachment 30 is secured by the quick hitch 50. That is, the attachment 30 is attached to the quick hitch 50 and to the working vehicle 1.

It is noted here that the driver may, after causing the first cutout 50al and/or the second cutout 50a2 to engage with the mounting pin(s) 30a, cause the boom 14, the arm 15, or the quick hitch 50 to swing upward by a predetermined angle using the work operator 7 to slightly lift the attachment 30 with the working device 4, in order to check whether the first cutout 50al and/or the second cutout 50a2 engage with the mounting pin(s) 30a.

During the steps of attaching the attachment 30 described above, the attachment 30 vibrates, for example, when the first cutout 50al and/or the second cutout 50a2 engage(s) with the mounting pin(s) 30a, when the attachment 30 is raised by the working device 4, and/or the like. The advertisement signal Q1 transmitted by the beacon transmitter 33 includes vibration information relating to the vibration state of the attachment 30 that has been detected by the vibration sensor 34 at any of the above-listed instances.

FIG. 11 is a flowchart showing an example of the securing-of-attachment recognizing process. If the operation actuator 26 is operated continuously (continues to be in ON state) for a first predetermined period of time T1 or more (S11 in FIG. 11) as described earlier, the controller 21 determines that the attachment 30 is attached to (secured to) the quick hitch 50. Next, in the case where the automatic selection mode is selected (YES in S12), the controller 21 determines whether or not any attachment IDs are stored in the internal memory 21a.

If the internal memory 21a stores one or more attachment IDs and corresponding one or more RSSIs therein (YES in S13), the controller 21 reads the one or more RSSIs and the one or more attachment IDs stored in the internal memory 21a, and selects one of the one or more attachment IDs that corresponds to the highest one of the RSSIs (S14). Next, the controller 21 identifies (recognizes) the attachment 30 attached to the quick hitch 50 based on the selected attachment ID (S15).

The one of the one or more advertisement signals Q1 received by the beacon scanner 23 that has the highest RSSI is a signal transmitted from the beacon transmitter 33 located closest to the beacon scanner 23. Therefore, the controller 21 regards, as the attachment ID of the attachment 30 attached to the quick hitch 50, the attachment ID included in an advertisement signal Q1 having the highest RSSI of advertisement signals Q1 received by the beacon scanner 23 during the period of time T4 which ended when the attachment 30 was attached to the quick hitch 50, and selects that attachment ID. Next, the controller 21 identifies the type, other specifications, and/or the like of the attachment 30 attached to the quick hitch 50 based on the selected attachment ID.

The attachment ID corresponding to the highest RSSI as described above is a predetermined condition based on which one of attachment ID(s) collected in the internal memory 21a is to be selected. Note that the RSSIs stored in the internal memory 21a may include one or more highest RSSIs. If a plurality of the highest RSSIs are stored in the internal memory 21a, such RSSIs have the same value and correspond to the same attachment ID. Therefore, the controller 21 may select one of the same attachment IDs (for example, the attachment ID corresponding to the latest receipt time) and identify the attachment 30 attached to the quick hitch 50 based on the selected attachment ID.

Next, the controller 21 causes the storing device 22 to store the result of identification of the attachment 30 (S16). It is noted here that the controller 21 causes the storing device 22 to store information indicating that the identified attachment 30 is attached to the quick hitch 50, i.e., to the working vehicle 1, and the attachment ID of the attached attachment 30.

The controller 21 starts a display process (predetermined process) in which the controller 21 causes the user interface 25 to display (output) an “attachment is attached” screen G1 which indicates that the attachment 30 corresponding to the selected attachment ID is attached and which displays attachment information relating to the attached attachment 30 (S17).

FIG. 12 illustrates an example of the “attachment is attached” screen G1. The “attachment is attached” screen G1 displays a message indicating that the attachment 30 is attached, the attachment information relating to the attached attachment 30, and an icon of the attachment 30. In the example in FIG. 12, the attachment information “Large bucket” “for excavation” is displayed. Additionally or alternatively, other attachment information such as the attachment ID, size, and/or manufacturer of the attachment 30 may be displayed (the same applies to FIG. 11 described later). The display data for the “attachment is attached” screen G1 and the attachment information are prestored in the storing device 22.

For another example, the controller 21 may cause the communicator 24 (FIG. 3) to transmit, to the portable device 70, the display data for the “attachment is attached” screen G1 and the attachment information of the attachment 30 which has been determined as being attached so that the “attachment is attached” screen G1 is displayed on a display of the portable device 70.

The controller 21 starts predetermined control (predetermined process) according to the attachment ID selected in step S14 (S18). In so doing, the controller 21 reads control data corresponding to the selected attachment ID form the storing device 22 and starts control corresponding to the attachment 30 attached to the quick hitch 50 based on the control data.

Specifically, in the case where the attachment 30 attached to the quick hitch 50 is an attachment 30B including a hydraulic actuator such as a grapple, the controller 21 starts causing the control valve 40d to control the output of hydraulic fluid from the hydraulic fluid outlet port 48a to the attachment 30B, based on the control data read from the storing device 22. With this, draining of return fluid to be introduced from the attachment 30B into the hydraulic fluid inlet port 48b is also started. The controller 21 may, for example, cause the “attachment is attached” screen G1 to display a message indicating that the control of the output of hydraulic fluid to the attachment 30 has been started.

Note that, in the case where the attachment 30 attached to the quick hitch 50 is an attachment 30 including no hydraulic actuators such as a bucket 30A, the controller 21 does not cause the control valve 40d to output hydraulic fluid from the hydraulic fluid outlet port 48a to the attachment 30 based on the control data read from the storing device 22. The controller 21 may start control such as adjusting and/or limiting the travel speed and/or speed stage of the working vehicle 1 and/or the height of the raised/lowered boom 14 according to the selected attachment ID in step S18.

On the contrary, if the internal memory 21a stores no attachment IDs or RSSIs (NO in S13), the controller 21 determines whether or not the beacon scanner 23 has received any advertisement signals Q1 from beacon transmitter(s) 33. For example, assume that the beacon scanner 23 receives an advertisement signal Q1 within a third predetermined period of time T3 (NO in S20) from when the operation actuator 26 has been operated continuously for the first predetermined period of time T1 or more (S11) (YES in S19). In such a case, the controller 21 identifies the attachment 30 attached to the quick hitch 50 based on the attachment ID included in this advertisement signal Q1 (S21). Next, the controller 21 causes the storing device 22 to store the result of identification of the attachment 30 as described earlier (S16), and starts a predetermined process according to the attachment ID included in the received advertisement signal Q1 (S17, S18).

For another example, in the case where the beacon scanner 23 receives a plurality of advertisement signals Q1 within the third predetermined period of time T3 (YES in S19), the controller 21 may determine at least one of whether the advertisement signals Q1 have an RSSI satisfying the selection condition or whether the advertisement signals Q1 include vibration information indicating that the corresponding attachment 30 is vibrating. The controller 21 may, if the RSSI of any of the advertisement signals Q1 is higher than a predetermined value X and/or any of the advertisement signals Q1 includes vibration information indicating that the attachment 30 is vibrating, identify the attachment 30 attached to the quick hitch 50 based on the attachment ID included in that advertisement signal Q1 (S21). The controller 21 may cause the storing device 22 to store the result of identification of the attachment 30 (S16) and start a predetermined process according to the attachment ID included in the advertisement signal Q1 (S17, S18).

If the beacon scanner 23 does not receive any advertisement signals Q1 within the third predetermined period of time T3 (NO in S19, YES in S20), the controller 21 causes the user interface 25 to display an attachment list L1 indicating attachment(s) 30 attachable to the quick hitch 50 (S22). Note that the third predetermined period of time T3 is, for example, about 10 seconds.

FIG. 13 shows an example of the attachment list L1. The data of the attachment list L1 is stored in the storing device 22. The attachment list L1 displayed by the user interface 25 includes, for example, pieces of attachment information such as the names, the attachment IDs, and/or the specifications of the attachments 30 attachable to the quick hitch 50.

The user selects a piece of attachment information relating to the attachment 30 attached to the quick hitch 50 from the attachment list using the user interface 25 (S23). Upon the selection, the controller 21 identifies the attachment 30 attached to the quick hitch 50 based on the selected piece of attachment information (S24). Then, the controller 21 causes the result of identification of the attachment 30 to be stored as described above (S16), and starts a predetermined process according to the selected piece of attachment information (S17, S18).

Also in the case where the manual selection mode is selected instead of the automatic selection mode (NO in S12) when the operation actuator 26 has been operated continuously for the first predetermined period of time T1 or more (S11), the controller 21 causes the user interface 25 to display the attachment list (S22). Next, upon selection of a piece of attachment information by the user from the attachment list (S23), the controller 21 identifies the attachment 30 attached to the quick hitch 50 based on the selected piece of attachment information (S24). Next, the controller 21 causes the result of identification of the attachment 30 to be stored as describe earlier (S16), and starts a predetermined process according to the selected piece of attachment information (S17, S18).

The controller 21 may cause the user interface 25 to display icon(s) (symbol(s)) of the attachment(s) 30 attachable to the quick hitch 50 instead of the attachment list L1 of step S22, for example. In such a case, upon selection (designation) of any of the icons using the user interface 25 by the user, the controller 21 reads the piece of attachment information of the attachment 30 corresponding to the selected icon from the storing device 22, identifies the attachment 30 attached to the quick hitch 50 based on the piece of attachment information, and starts a predetermined process corresponding to the piece of attachment information (S17, S18).

Alternatively, the controller 21 may cause the user interface 25 to display an input screen for attachment information such as an attachment ID instead of the attachment list L1 of step S22. In such a case, upon input of a piece of attachment information of the attachment 30 attached to the quick hitch 50 by the user via the input screen on the user interface 25, the controller 21 identifies the attachment 30 attached to the quick hitch 50 based on the inputted piece of attachment information and starts a predetermined process corresponding to the piece of attachment information (S17, S18).

The controller 21 may cause the user interface 25 to also display prompt information (such as a message) asking for selection or input of a piece of attachment information or an icon corresponding to the attachment 30 attached to the quick hitch 50, when causing the user interface 25 to display the foregoing attachment list L1, icons of the attachments 30, or the input screen for the attachment information.

In the attachment information collecting process shown in FIG. 9, the controller 21 selects one of the advertisement signals Q1 received by the beacon scanner 23 that has an RSSI satisfying the selection condition and that includes vibration information indicating that the attachment 30 is vibrating (YES in S4, YES in S6), and causes the internal memory 21a to store (collect) only the attachment(s) ID included in such advertisement signal(s) Q1 (S7). Note, however, that the controller 21 may, among the following two: the RSSI of the advertisement signal Q1 received by the beacon scanner 23 satisfies the selection condition; and the advertisement signal Q1 includes vibration information indicating that the attachment 30 is vibrating, in the case where it is determined that at least the RSSI satisfies the selection condition, cause the internal memory 21a to store the attachment ID(s) included in such advertisement signal(s) Q1.

Specifically, as shown in FIG. 14, the controller 21 may select one or more of the advertisement signal(s) Q1 received by the beacon scanner 23 that have an RSSI satisfying the selection condition (YES in S4) and cause the internal memory 21a to store only the attachment ID(s) included in the one or more advertisement signals Q1 (S5, S7). In the case where the attachment information collecting process is performed as shown in FIG. 14, the controller 21 need only perform the securing-of-attachment recognizing process as discussed with reference to FIG. 11.

For another example, the controller 21 may cause the internal memory 21a to store the attachment ID(s) included in all the advertisement signal(s) Q1 received by the beacon scanner 23 from the beacon transmitter(s) 33 and, in the securing-of-attachment recognizing process, select attachment ID(s) with an RSSI satisfying the selection condition. Specifically, for example, as shown in FIG. 15, after the controller 21 receives advertisement signal(s) Q1 (S2) and acquires the RSSI(s) of the advertisement signal(s) Q1 (S3), the controller 21 causes the internal memory 21a to store the attachment ID and information such as vibration information included in each advertisement signal Q1 and the RSSI of the advertisement signal Q1 such that the information and the RSSI are associated with each other (S7a). In so doing, the controller 21 causes the internal memory 21a to also store the first threshold and/or the second threshold and/or postures etc. to be used to acquire the threshold(s) such that the first threshold and/or the second threshold and/or the postures etc. to be used to acquire the threshold(s) are associated with the attachment ID and the information such as vibration information and the RSSI.

With this, as shown in FIG. 16, the attachment IDs and pieces of vibration information included in all the advertisement signals Q1 received by the beacon scanner 23 are collected in the internal memory 21a. In the example shown in FIG. 16, the attachment ID and information such as vibration information and the RSSI, as well as the postures, are associated with each other and collected in the internal memory 21a. In such a case, the controller 21 may perform the securing-of-attachment recognizing process as shown in FIG. 17 or 18, for example.

In FIG. 17, in the case where the internal memory 21a stores attachment ID(s), RSSI(s) and postures (YES in S13a), the controller 21 extracts one or more of the RSSI(s) stored in the internal memory 21a that satisfy the selection condition (S25). That is, the controller 21 extracts RSSI(s) greater than the first threshold and equal to or less than the second threshold.

If a single RSSI is extracted (YES in S26), the controller 21 selects the attachment ID corresponding to that RSSI from the internal memory 21a and identifies the attachment 30 attached to the quick hitch 50 based on the attachment ID (S15).

In contrast, if two or more RSSIs are extracted (NO in S26), the controller 21 selects the attachment ID corresponding to the highest one of the extracted RSSIs (S14). The controller 21 then identifies the attachment 30 attached to the quick hitch 50 based on the selected attachment ID (S15).

In FIG. 18, in the case where the internal memory 21a stores attachment ID(s), RSSI(s), piece(s) of vibration information, and postures (YES in S13b), the controller 21 extracts one or more of the attachment ID(s) that correspond to RSSI(s) satisfying the selection condition and correspond to piece(s) of vibration information indicating that the corresponding attachment 30 is vibrating (S27). If a single attachment ID is extracted (YES in S28), the controller 21 identifies the attachment 30 attached to the quick hitch 50 based on that attachment ID (S15). That is, the controller 21 selects the extracted attachment ID as the attachment ID of the attachment 30 attached to the quick hitch 50.

On the contrary, if two or more attachment IDs are extracted (NO in S28), the controller 21 selects the attachment ID that corresponds to the highest one of the RSSIs satisfying the selection condition (S14). The controller 21 then identifies the attachment 30 attached to the quick hitch 50 based on the selected attachment ID (S15).

In the securing-of-attachment recognizing process in FIGS. 17 and 18, after the controller 21 performs step S15, the controller 21 causes the result of identification of the attachment 30 to be stored as described earlier (S16) and starts a predetermined process corresponding to the selected attachment ID (S17, S18). In the case where the internal memory 21a stores no attachment IDs (NO in S13a, No in S13b) or in the case where the manual selection mode is selected (NO in S12), the controller 21 performs steps S19 to S24 as described earlier.

The above description of example embodiments with reference to the drawings such as FIG. 9 discusses example cases in which the controller 21 selects the attachment ID corresponding to the highest RSSI from the piece(s) of information (attachment ID(s), RSSI(s) and/or the like) stored in the internal memory 21a. However, alternatively, the controller 21 may select, from the piece(s) of information stored in the internal memory 21a, the attachment ID corresponding to the RSSI which is closest to a predetermined third threshold corresponding to the relative position obtained when the beacon scanner 23 receives the advertisement signal Q1.

In such a case, in the attachment information collecting process, the controller 21 associates the attachment ID(s) and the information such as the vibration information and the RSSI with the postures for use in calculation of the third threshold, etc., and causes the internal memory 21a to store them. The third threshold is, similarly to the first threshold and the second threshold, a value that corresponds to the relative position obtained when the advertisement signal Q1 is received. In the case where the relative distance between the machine body 2 or the receiver 23 and the linkage 50 is a predetermined first distance, the third threshold is greater than when the relative distance is a predetermined second distance shorter than the first distance. The third threshold is defined to decrease in value as the relative distance increases. The third threshold is defined to decrease in value as the relative distance decreases. The controller 21 acquires the third threshold based on the postures. The controller 21 acquires the third threshold by correcting a predetermined third reference value based on, for example, the postures.

The controller 21 may select attachment ID(s) satisfying a predetermined condition relating to RSSI from pieces of information collected in the internal memory 21a, such as the attachment ID that corresponds to the RSSI which has been determined as being equal to or higher than the third threshold the predetermined number of times.

Alternatively, the controller 21 may select attachment ID(s) satisfying a predetermined condition relating to vibration information of the attachment 30 from pieces of information collected in the internal memory 21a, such as the attachment ID that corresponds to the vibration indicator closest to a predetermined vibration threshold or the attachment ID that corresponds to a vibration indicator which has been determined as being equal to or greater than the vibration threshold the predetermined number of times. Additionally or alternatively, the controller 21 may detect time series variations in RSSI or vibration information collected in the internal memory 21a and select attachment ID(s) which match a predetermined variation. That is, the controller 21 may select one or more of the attachment ID(s) collected in the internal memory 21a based on a predetermined condition relating to at least one of RSSI or vibration information.

The above description of example embodiments discusses cases in which the selection condition includes a condition in which the attachment ID to be selected by the controller 21 is an attachment ID included in an advertisement signal Q1 with an RSSI higher than the first threshold and/or equal to or lower than the second threshold. Note, however, that the controller 21 need only select an attachment ID based on at least a selection condition that varies depending on the relative position of the quick hitch 50 relative to the machine body 2. For example, the controller 21 corrects a received signal strength (RSSI) according to the relative distance between the machine body 2 or the receiver (beacon scanner) 23 and the linkage (quick hitch) 50, and the selection condition includes a condition in which the identification information is to be selected by the controller 21 based on the value of the corrected received signal strength (RSSI′) relative to a predetermined reference value. The reference value is, for example, the first threshold and/or the second threshold, and is a predetermined value defined in advance. That is, this variation differs from the above example embodiments in that, with regard to the selection condition that varies depending on the relative position, the reference value(s) is/are changed to obtain the first threshold and/or second threshold based on the relative position in the above example embodiments, whereas the RSSI is corrected based on the relative position in this variation.

The reference value(s) is/are stored in a predetermined storage area of the storing device 22. In the case where the reference value(s) include the first threshold, the controller 21 selects attachment ID(s) included in advertisement signal(s) Q1 with a corrected RSSI higher than the first threshold. In the case where the reference value(s) include(s) the second threshold, the controller 21 selects attachment ID(s) included in advertisement signal(s) Q1 with a corrected RSSI equal to or lower than the second threshold. Note that in the case where the reference values include both the first threshold and the second threshold, the second threshold is defined to be greater than the first threshold.

The following details the correction of RSSI by the controller 21. The controller 21 corrects the RSSI (the corrected RSSI may be referred to as “RSSI′”) based on the relative position obtained when a corresponding advertisement signal Q1 is received. Note that, in this case, the RSSI′ used to select identification information is not limited to the one corrected based on the relative position at the point in time when the beacon scanner 23 receives the advertisement signal Q1, and may be the one corrected based on the relative position obtained before or after the receipt of the advertisement signal Q1 by the beacon scanner 23.

In the case where the relative distance is a predetermined first distance, the controller 21 corrects the RSSI such that the corrected RSSI is greater than when the relative distance is a predetermined second distance shorter than the first distance. For example, the controller 21 corrects the RSSI by multiplying an RSSI by a third correction value. In other words, the third correction value is a correction factor to be used to correct the RSSI.

FIG. 19 is a graph showing the relationship between the third correction value and the corresponding relative distance. As shown in FIG. 19, the third correction factor is defined to increase in value as the relative distance increases. The third correction value is defined to decrease in value as the relative distance decreases. In the present example embodiment, as shown in FIG. 19, there is a proportional relationship or a relationship close to a proportional relationship (third correlation) between the third correction value and the relative distance. Thus, the function representing the relationship between the third correction value and the relative distance is defined to form a straight line or a substantially straight line.

Thus, in the case where the relative distance based on the postures is longer than a reference distance, the third correction value is greater than 1. In the case where the relative distance based on the postures is equal to the reference distance, the third correction value is 1 and RSSI is not substantially corrected. In the case where the relative distance based on the postures is shorter than the reference distance, the third correction value is less than 1.

Note that the third correction value does not need to be proportional to the relative distance, and that the function representing the relationship between the third correction value and the relative distance may be, for example, defined to form a curve. Specifically, the third correction value may be defined to sharply increase after gradually increasing as the relative distance increases, and may be defined to gradually increase after sharply increasing as the relative distance increases.

The controller 21 acquires the third correction value based on the boom posture and the arm posture. Since the controller 21 can calculate other postures (swing posture and hitch posture) in addition to the boom posture and the arm posture, in the present example embodiment, the controller 21 acquires the third correction value based on such postures.

The controller 21 corrects the RSSI based at least on the boom posture and the arm posture. Since the controller 21 can calculate the swing posture, the boom posture, the arm posture and the hitch posture, in the present example embodiment, the controller 21 acquires the third correction value based on such postures, and corrects the RSSI using the third correction value.

The third correction value is associated with the relative distance or the postures in a table (third correction table) and stored in a predetermined storage area of the storing device 22. The controller 21 acquires the third correction value from the postures and the third correction table. The controller 21 corrects the RSSI using the acquired third correction value.

Note that the third correction values in the third correction table stored in the storing device 22 may be freely editable (changeable) by the driver using the user interface 25 and/or the portable device 70. The above description discusses example cases in which the controller 21 corrects the RSSI by multiplying the RSSI by the third correction value, but the method of correcting the RSSI using the third correction value is not limited to multiplying. Specifically, the controller 21 may correct the RSSI by dividing the RSSI by the third correction value, or may correct the RSSI by adding or subtracting the third correction value to or from the RSSI. The third correction value is appropriately defined based on the method of correcting the RSSI.

The following discusses cases in which the controller 21 acquires both the first threshold and the second threshold as the reference values and in which the selection condition is such that the identification information (attachment ID) to be selected by the controller 21 is identification information (attachment ID) included in a wireless signal Q1 (advertisement signal Q1) with a corrected RSSI (RSSI′) greater than the first threshold and equal to or less than the second threshold. FIG. 20 is a flowchart showing another example of an attachment information collecting process according to such a variation.

In the case where the controller 21 is in the automatic selection mode (S31 in FIG. 20), when the controller 21 receives an advertisement signal Q1 from a beacon transmitter 33 via the beacon scanner 23 (S32), the controller 21 acquires the attachment ID and the RSSI of the advertisement signal Q1 from the beacon scanner 23 (S33).

Next, the controller 21 corrects the RSSI according to the relative distance to calculate the RSSI′ (S34). Specifically, the controller 21 calculates postures from the signal(s) detected by the posture detector 49, and acquires the third correction value based on the calculated postures. Then, the controller 21 corrects the RSSI using the acquired third correction value to calculate the RSSI′.

In the case where the corrected RSSI (RSSI′) satisfies the selection condition (YES at S35), the controller 21 reads information included in the received advertisement signal Q1 (S36). Specifically, in the case where the controller 21 determines that the corrected RSSI (RSSI′) is greater than the first threshold and equal to or less than the second threshold and satisfies the selection condition, the controller 21 reads information included in the received advertisement signal Q1.

Next, if the information read from the advertisement signal Q1 includes vibration information indicating that the attachment 30 is vibrating, the controller 21 determines that there is vibration on the attachment 30 (YES at S37). Alternatively, if the information read from the advertisement signal Q1 includes a vibration indicator and the vibration indicator is greater than a predetermined value (second predetermined value) Y, the controller 21 determines that there is vibration on the attachment 30 (YES at S37).

The controller 21 then causes the internal memory 21a to store the attachment ID included in the received advertisement signal Q1 and the corrected RSSI (RSSI′) of the advertisement signal Q1 such that the attachment ID and the RSSI′ are associated with each other (S38). In so doing, the controller 21, for example, causes the internal memory 21a to also store information indicating the time when the attachment ID and the RSSI′ were stored (timestamp and/or the like) such that the information is associated with the attachment ID and the RSSI′.

On the other hand, if the corrected RSSI (RSSI′) of the received advertisement signal Q1 does not satisfy the selection condition (NO at S35), the controller 21 does not cause the internal memory 21a to store the attachment ID included in the received advertisement signal Q1 or the corrected RSSI (RSSI′) of the advertisement signal Q1. That is, in the present example embodiment, in the case where the controller 21 determines that the acquired RSSI′ is equal to or lower than the first threshold or higher than the second threshold and does not satisfy the selection condition, the controller 21 does not cause the internal memory 21a to store the attachment ID included in the received advertisement signal Q1 or the RSSI′ of the advertisement signal Q1. Also when the received advertisement signal Q1 does not include vibration information indicating that the attachment 30 is vibrating (or a vibration indicator greater than a predetermined value Y) and the controller 21 determines that there is no vibration on the attachment 30 (NO at S37), the controller 21 does not cause the internal memory 21a to store the attachment ID included in the received advertisement signal Q1 or the RSSI′ of the advertisement signal Q1.

If the internal memory 21a stores any attachment ID and corrected RSSI (RSSI′) stored for a period of time T4 or more (YES at S39), the controller 21 deletes the attachment ID and the RSSI′ from the internal memory 21a (S40). In so doing, the controller 21 also deletes the other information (time information and/or the like) corresponding to the attachment ID stored for the period of time T4 or more from the internal memory 21a. After step S40, the controller 21 repeats step S31 and subsequent steps.

FIG. 21 is a diagram showing information stored in the internal memory 21a of the controller 21. The controller 21 repeats the attachment information collecting process of FIG. 20, so that the attachment IDs and the corresponding corrected RSSIs (RSSI's) are collected in the internal memory 21a as shown in FIG. 21.

FIG. 22 is a flowchart showing an example of a securing-of-attachment recognizing process according to a variation. As mentioned earlier, when the operation actuator 26 is continuously operated (continues to be turned ON) for a first predetermined period of time T1 or more (S41 at FIG. 22), the controller 21 determines that an attachment 30 is attached (secured) to the quick hitch 50. Then, in the case where the controller 21 is in the automatic selection mode (YES at S42), the controller 21 determines whether the internal memory 21a stores attachment ID(s).

If the internal memory 21a stores at least one attachment ID and the corresponding at least one corrected RSSI (RSSI′) (YES at S43), the controller 21 reads the RSSI′ (s) and the attachment ID(s) stored in the internal memory 21a, and selects one of the attachment ID(s) that corresponds to the highest corrected RSSI (RSSI′) (S44). Then, the controller 21 proceeds to step S15 and identifies (recognizes) the attachment 30 attached to the quick hitch 50 based on the selected attachment ID (S15). The attachment ID corresponding to the highest RSSI′ is included in a predetermined condition based on which an attachment ID is to be selected from the attachment ID(s) stored in the internal memory 21a, and the predetermined condition may include condition(s) discussed in other example embodiments/variations.

On the other hand, if the internal memory 21a stores no attachment IDs or corrected RSSIs (RSSI's) (NO at S43), the controller 21 determines whether an advertisement signal Q1 from a beacon transmitter 33 has been received by the beacon scanner 23, and performs steps S19 to S21. In so doing, in the case where a plurality of advertisement signals Q1 are received by the beacon scanner 23 within a third predetermined period of time T3 (YES at S19), the controller 21 may determine (i) whether the corrected RSSI (RSSI′) of each advertisement signal Q1 satisfies the selection condition and/or (ii) whether the advertisement signal Q1 includes vibration information indicating that the attachment 30 is vibrating.

Then, the controller 21 causes the result of identification of the attachment 30 to be stored as mentioned earlier (S16), and starts a predetermined process based on the selected attachment information (S17 and S18).

Also in the case where the controller 21 is not in the automatic selection mode (NO at S42) but in the manual selection mode when the operation actuator 26 is continuously operated for a first predetermined period of time T1 or more (S41), the controller 21 proceeds to step S22.

Note that detailed descriptions are not provided for the cases where the selection condition used by the controller 21 only relates to the first threshold and the cases where the selection condition used by the controller 21 only relates to the second threshold, because the only difference is the criterion based on which to determine whether the RSSI′ satisfies the selection condition. The variation described using FIG. 22 can be combined with the variations of FIGS. 17 and/or 18, and detailed descriptions therefor are omitted.

The above description of example embodiments discusses example cases in which the position changer C includes the support 10, the boom 14, the arm 15, the boom cylinder 16 and the arm cylinder 17. Note, however, that in the case where the beacon scanner 23 is attached to the traveling device 5, the position changer C may include the swivel motor. In such a case, the controller 21 calculates the posture of the machine body 2 (angle of swivel about the swivel axis 2b) relative to the traveling device 5 (which is an example of calculation of the posture of the position changer C), and selects an attachment ID using the selection condition in consideration of the posture.

In the above-described example embodiments, each attachment 30 is provided with a beacon transmitter 33 to transmit a wireless signal (advertisement signal Q1) compliant with Bluetooth (registered trademark) Low Energy, and the working vehicle 1 is provided with a beacon scanner 23 to receive the wireless signals. However, additionally or alternatively, for example, the attachment 30 may be provided with a transmitter such as a radio frequency identification (RFID) tag, and the working vehicle 1 may be provided with a receiver to receive wireless signals transmitted from the RFID. Additionally or alternatively, the attachment 30 may be provided with a transmitter to transmit radio waves for some other near field communication, and the working vehicle 1 may be provided with a receiver to receive the radio waves.

In the above-described example embodiments, the working vehicle 1 is provided with the quick hitch 50. Alternatively, the working vehicle 1 may be provided with a hitch having a different structure from the quick hitch 50, a quick hitch 50 to which an attachment 30 can be attached and detached both automatically and manually, or a hitch to which an attachment 30 can be attached and detached only manually. In the case where the user manually attaches the attachment 30 to the hitch or manually detaches the attachment 30 from the hitch, the user may input information indicating that the attachment 30 is attached or detached using the user interface 25.

In the above-described example embodiments, the user inputs attachment information relating to the attachment 30 attached to the quick hitch 50 using the user interface 25 provided in or on the working vehicle 1. However, for example, the user may input attachment information relating to the attachment 30 attached to the quick hitch 50 using a portable device 70. That is, the portable device 70 may be used as a user interface 25 instead of the above-descried user interface 25.

In such a case, upon input of attachment information into the portable device 70, the portable device 70 transmits the attachment information to the communicator 24 of the working vehicle 1 via the Internet and/or the like. Upon receipt of the attachment information by the communicator 24, the controller 21 of the working vehicle 1 recognizes the attachment 30 attached to the quick hitch 50 based on the attachment ID included in the attachment information.

In the above-described example embodiments, the working device 4, the quick hitch 50, and the specific attachment 30B are provided with hydraulic actuators (such as the swing cylinder 13, the arm cylinder 17, the boom cylinder 16, the bucket cylinder 19, the hitch cylinder 53). Additionally or alternatively, the working device 4, the quick hitch 50, and the specific attachment 30 may be provided with electric actuators. In the case where an attachment including an electric actuator is attached to the quick hitch 50, the controller 21 may output, as power for the electric actuator, electricity (power) from the battery 20 (FIG. 3) to the attachment 30 via an external electric wire based on control data corresponding to the attachment 30.

An attachment including a work member to be actuated by power from the prime mover 9 of the working vehicle 1 may be attached to the quick hitch 50. In the case where such an attachment including a work member is attached to the quick hitch 50, the controller 21 need only output power from the prime mover 9 to the attachment via a power transmission mechanism including gear(s), shaft(s), and/or the like based on control data corresponding to the attachment.

Example embodiments of the present invention provide working vehicles 1 and attachment usage systems 100 described in the following items.

(Item 1) A working vehicle 1 including a machine body 2, a position changer C provided on the machine body 2, a linkage 50 provided on the position changer C to attach and detach an attachment 30 thereto and therefrom, a receiver 23 provided in or on the machine body 2 to receive one or more wireless signals Q1 which are transmitted periodically from one or more transmitters 33 in or on one or more of the attachments 30, which include respective one or more pieces of identification information of the one or more attachments 30, and which are compliant with a near field communication standard, and a controller 21 configured or programmed to, based on one or more received signal strengths of the one or more wireless signals Q1 received by the receiver 23, select a piece of identification information of the attachment 30 attached to the linkage 50 and perform a predetermined process based on the selected piece of identification information, wherein the position changer C is operable to be driven to change a relative position of the linkage 50 relative to the machine body 2, and the controller 21 is configured or programmed to select, based on a selection condition varying depending on the relative position, a piece of identification information included in a wireless signal Q1 with a received signal strength which satisfies the selection condition.

With the working vehicle 1 according to item 1, the controller 21 is able to cause the selection condition, based on which identification information is to be selected, to vary depending on the relative position of the linkage 50 relative to the machine body 2. This achieves the following. There may be cases in which, if the relative position of the linkage 50 relative to the machine body 2 (i.e., the relative distance between the receiver 23 in or on the machine body 2 and the transmitter 33 in or on the attachment 30 attached to the linkage 50) changes as the position changer C is driven, the received signal strength of the wireless signal Q1 received by the receiver 23 changes even if the distance between the linkage 50 and the attachment 30 stays the same. Even if this is the case, the controller 21 makes it possible to maintain the accuracy of selecting identification information by causing the selection condition to vary depending on the relative position. It follows that the working vehicle 1 is able to accurately recognize (detect) the attachment 30 attached to the linkage 50 and smoothly perform a predetermined process, making it possible to efficiently use replaceable attachments 30 on the working vehicle 1.

(Item 2) The working vehicle 1 according to item 1, wherein the controller 21 is configured or programmed to acquire a first threshold having a value that varies depending on the relative position, and the selection condition includes a condition in which the piece of identification information to be selected by the controller 21 is a piece of identification information included in a wireless signal Q1 with a received signal strength greater than the first threshold.

With the working vehicle 1 according to item 2, since the controller 21 causes the value of the first threshold to vary depending on the relative position, the controller 21 is able, even if the received signal strength changes as the relative position changes, to appropriately recognize the attachment 30 attached to the linkage 50 by excluding attachments 30 relatively distant from the receiver 23 and distant from the linkage 50 using the first threshold.

(Item 3) The working vehicle 1 according to item 2, wherein the controller 21 is configured or programmed to, when a relative distance between the machine body 2 or the receiver 23 and the linkage 50 is a first distance, acquire the first threshold having a value less than when the relative distance is a second distance which is shorter than the first distance.

With the working vehicle 1 according to item 3, the controller 21 is able to acquire an appropriate first threshold depending on the relative distance between the machine body 2 or the receiver 23 and the linkage 50. This achieves the following. Even if the distance between the linkage 50 and the attachment 30 stays the same, the received signal strength of the wireless signal Q1 received from the transmitter 33 attached to the attachment 30 increases as the relative distance decreases. Even in this case, the controller 21 is able, by acquiring a relatively large first threshold, to appropriately determine the attachment 30 attached to the linkage 50. On the contrary, even if the distance between the linkage 50 and the attachment 30 stays the same, the received signal strength of the wireless signal Q1 received from the transmitter 33 attached to the attachment 30 decreases as the relative distance increases. Even in this case, the controller 21 is able, by acquiring a relatively small first threshold, to eliminate or reduce the likelihood that the attachment 30 will not be recognized.

(Item 4) The working vehicle 1 according to any one of items 1 to 3, wherein the position changer C includes a boom 14 supported on the machine body 2 such that the boom 14 is swingable up and down, and an arm 15 swingably connected to a distal portion of the boom 14, and the linkage 50 is swingably connected to a distal portion of the arm 15.

With the working vehicle 1 according to item 4, the following is achieved. If the boom 14 and/or the arm 15 swings and therefore the relative position of the linkage 50 relative to the machine body 2 changes relatively greatly, the received signal strength of the wireless signal Q1 received by the receiver 23 from the transmitter 33 in or on the attachment 30 changes relatively greatly even if the distance between the linkage 50 and the attachment 30 stays the same. Even if this is the case, the controller 21 is able to appropriately recognize the attachment 30 attached to the linkage 50.

(Item 5) The working vehicle 1 according to item 4, further including a posture detector 49 to detect a posture of the boom 14 relative to the machine body 2 and a posture of the arm 15 relative to the boom 14, wherein the controller 21 is configured or programmed to acquire the first threshold based on the posture of the boom 14 and the posture of the arm 15 detected by the posture detector 49.

With the working vehicle 1 according to item 5, the controller 21 is able to easily and reliably acquire a first threshold corresponding to the relative position based on the postures of the boom 14 and the arm 15. This makes it possible for the controller 21 to more accurately recognize the attachment 30 attached to the linkage 50.

(Item 6) The working vehicle 1 according to item 5, wherein the controller 21 is configured or programmed to acquire the first threshold by correcting a first reference value based on the posture of the boom 14 and the posture of the arm 15.

With the working vehicle 1 according to item 6, the controller 21 is able to acquire a first threshold corresponding to the postures of the boom 14 and the arm 15 via relatively simple computing.

(Item 7) The working vehicle 1 according to item 1, wherein the controller 21 is configured or programmed to acquire a first threshold having a value that varies depending on the relative position and a second threshold having a value that varies depending on the relative position, the second threshold being greater than the first threshold, and the selection condition includes a condition in which the piece of identification information to be selected by the controller 21 is a piece of identification information included in a wireless signal Q1 with a received signal strength greater than the first threshold and less than or equal to the second threshold.

With the working vehicle 1 according to item 7, the values of the first threshold and the second threshold are caused to vary depending on the relative position. With this, the controller 21 is able, even if the received signal strength changes as the relative position changes, to appropriately recognize the attachment 30 attached to the linkage 50 by excluding attachments 30 relatively distant from the receiver 23 and distant from the linkage 50 using the first threshold and by excluding attachments 30 located too close to the receiver 23 and distant from the linkage 50 using the second threshold.

(Item 8) The working vehicle 1 according to item 7, wherein the controller 21 is configured or programmed to, when a relative distance between the machine body 2 or the receiver 23 and the linkage 50 is a first distance, acquire the first threshold and the second threshold which have respective values less than when the relative distance is a second distance which is shorter than the first distance.

With the working vehicle 1 according to item 8, the controller 21 is able to acquire an appropriate first threshold and second threshold according to the relative distance between the machine body 2 or the receiver 23 and the linkage 50. This achieves the following. Even if the distance between the linkage 50 and the attachment 30 stays the same, the received signal strength of the wireless signal Q1 received from the transmitter 33 attached to the attachment 30 decreases as the relative distance increases, and increases as the relative distance decreases. Even if this is the case, the controller 21 is able, by acquiring the first threshold and the second threshold, to appropriately identify the attachment 30 attached to the linkage 50 while eliminating or reducing the likelihood that the attachment 30 attached to the linkage 50 will not be recognized.

(Item 9) The working vehicle 1 according to item 7 or 8, wherein the position changer C includes a boom 14 supported on the machine body 2 such that the boom 14 is swingable up and down, and an arm 15 swingably connected to a distal portion of the boom 14, and the linkage 50 is swingably connected to a distal portion of the arm 15.

With the working vehicle 1 according to item 9, the following is achieved. If the boom 14 and/or the arm 15 swings and therefore the relative position of the linkage 50 relative to the machine body 2 changes relatively greatly, the received signal strength of the wireless signal Q1 received by the receiver 23 from the transmitter 33 in or on the attachment 30 changes relatively greatly even if the distance between the linkage 50 and the attachment 30 stays the same. Even if this is the case, the controller 21 is able to appropriately recognize the attachment 30 attached to the linkage 50.

(Item 10) The working vehicle 1 according to item 9, further including a posture detector 49 to detect a posture of the boom 14 relative to the machine body 2 and a posture of the arm 15 relative to the boom 14, wherein the controller 21 is configured or programmed to acquire the first threshold and the second threshold based on the posture of the boom 14 and the posture of the arm 15 detected by the posture detector 49.

With the working vehicle 1 according to item 10, the controller 21 is able to easily and reliably acquire the first threshold and the second threshold corresponding to the relative position based on the postures of the boom 14 and the arm 15. This makes is possible for the controller 21 to more accurately recognize the attachment 30 attached to the linkage 50.

(Item 11) The working vehicle 1 according to item 10, wherein the controller 21 is configured or programmed to acquire the first threshold by correcting a first reference value based on the posture of the boom 14 and the posture of the arm 15, and acquire the second threshold by correcting a second reference value based on the posture of the boom 14 and the posture of the arm 15, the second reference value being greater than the first reference value.

With the working vehicle 1 according to item 11, the controller 21 is able to acquire the first threshold and the second threshold corresponding to the postures of the boom 14 and the arm 15 using relatively simple computing.

(Item 12) The working vehicle 1 according to item 1, wherein the controller 21 is configured or programmed to acquire a second threshold having a value that varies depending on the relative position, and the selection condition includes a condition in which the piece of identification information to be selected by the controller 21 is a piece of identification information included in a wireless signal Q1 with a received signal strength less than or equal to the second threshold.

With the working vehicle 1 according to item 12, the value of the second threshold is caused to vary depending on the relative position. With this, the controller 21 is able, even if the received signal strength changes as the relative position changes, to appropriately recognize the attachment 30 attached to the linkage 50 by excluding attachments 30 located too close to the receiver 23 and distant from the linkage 50 using the second threshold.

(Item 13) The working vehicle 1 according to item 12, wherein the controller 21 is configured or programmed to, when a relative distance between the machine body 2 or the receiver 23 and the linkage 50 is a first distance, acquire the second threshold having a value less than when the relative distance is a second distance which is shorter than the first distance.

With the working vehicle 1 according to item 13, the controller 21 is able to acquire an appropriate second threshold depending on the relative distance between the machine body 2 or the receiver 23 and the linkage 50. This achieves the following. Even if the distance between the linkage 50 and the attachment 30 stays the same, the received signal strength of the wireless signal Q1 received from the transmitter 33 attached to the attachment 30 decreases as the relative distance increases. Even in this case, the controller 21 is able, by acquiring a relatively small second threshold, to appropriately determine the attachment 30 attached to the linkage 50. On the contrary, even if the distance between the linkage 50 and the attachment 30 stays the same, the received signal strength of the wireless signal Q1 received from the transmitter 33 attached to the attachment 30 increases as the relative distance decreases. Even in this case, the controller 21 is able, by acquiring a relatively large second threshold, to eliminate or reduce the likelihood that the attachment 30 will not be recognized.

(Item 14) The working vehicle 1 according to item 12 or 13, wherein the position changer C includes a boom 14 supported on the machine body 2 such that the boom 14 is swingable up and down, and an arm 15 swingably connected to a distal portion of the boom 14, and the linkage 50 is swingably connected to a distal portion of the arm 15.

With the working vehicle 1 according to item 14, the following is achieved. If the boom 14 and/or the arm 15 swings and therefore the relative position of the linkage 50 relative to the machine body 2 changes relatively greatly, the received signal strength of the wireless signal Q1 received by the receiver 23 from the transmitter 33 in or on the attachment 30 changes relatively greatly even if the distance between the linkage 50 and the attachment 30 stays the same. Even if this is the case, the controller 21 is able to appropriately recognize the attachment 30 attached to the linkage 50.

(Item 15) The working vehicle 1 according to item 14, further including a posture detector 49 to detect a posture of the boom 14 relative to the machine body 2 and a posture of the arm 15 relative to the boom 14, wherein the controller 21 is configured or programmed to acquire the second threshold based on the posture of the boom 14 and the posture of the arm 15 detected by the posture detector 49.

With the working vehicle 1 according to item 15, the controller 21 is able to easily and reliably acquire a second threshold corresponding to the relative position based on the postures of the boom 14 and the arm 15. This makes it possible for the controller 21 to more accurately recognize the attachment 30 attached to the linkage 50.

(Item 16) The working vehicle 1 according to item 15, wherein the controller 21 is configured or programmed to acquire the second threshold by correcting a second reference value based on the posture of the boom 14 and the posture of the arm 15.

With the working vehicle 1 according to item 16, the controller 21 is able to acquire a second threshold corresponding to the postures of the boom 14 and the arm 15 via relatively simple computing.

(Item 17) The working vehicle 1 according to item 1, wherein the controller 21 is configured or programmed to correct the received signal strength based on a relative distance between the machine body 2 or the receiver 23 and the linkage 50, and the selection condition includes a condition in which the piece of identification information is to be selected by the controller 21 based on a value of the corrected received signal strength relative to a reference value.

With the working vehicle 1 according to item 17, the controller 21 is able, by correcting the received signal strength based on the relative distance, to appropriately recognize the attachment 30 attached to the linkage 50 even if the received signal strength changes as the relative position changes.

(Item 18) The working vehicle 1 according to item 17, wherein the controller 21 is configured or programmed to correct the received signal strength such that the corrected received signal strength is greater when the relative distance is a first distance than when the relative distance is a second distance which is shorter than the first distance.

With the working vehicle 1 according to item 18, the following is achieved. Even if the distance between the linkage 50 and the attachment 30 stays the same, the received signal strength of the wireless signal Q1 received from the transmitter 33 attached to the attachment 30 decreases as the relative distance increases, and increases as the relative distance decreases. Even if this is the case, the controller 21 is able, by correcting the received signal strength based on the relative distance, to appropriately identify the attachment 30 attached to the linkage 50 while eliminating or reducing the likelihood that the attachment 30 will not be recognized.

(Item 19) The working vehicle 1 according to item 17 or 18, wherein the position changer C includes a boom 14 supported on the machine body 2 such that the boom 14 is swingable up and down, and an arm 15 swingably connected to a distal portion of the boom 14, and the linkage 50 is swingably connected to a distal portion of the arm 15.

With the working vehicle 1 according to item 19, the following is achieved. If the boom 14 and/or the arm 15 swings and therefore the relative position of the linkage 50 relative to the machine body 2 changes relatively greatly, the received signal strength of the wireless signal Q1 received by the receiver 23 from the transmitter 33 in or on the attachment 30 changes relatively greatly even if the distance between the linkage 50 and the attachment 30 stays the same. Even if this is the case, the controller 21 is able to appropriately recognize the attachment 30 attached to the linkage 50.

(Item 20) The working vehicle 1 according to item 19, further including a posture detector 49 to detect a posture of the boom 14 relative to the machine body 2 and a posture of the arm 15 relative to the boom 14, wherein the controller 21 is configured or programmed to correct the received signal strength based on the posture of the boom 14 and the posture of the arm 15 detected by the posture detector 49.

With the working vehicle 1 according to item 20, the controller 21 is able, by correcting the received signal strength based on the postures of the boom 14 and the arm 15, to easily and reliably acquire the received signal strength corresponding to the relative position. This makes it possible for the controller 21 to more accurately recognize the attachment 30 attached to the linkage 50.

(Item 21) The working vehicle 1 according to any one of items 17 to 20, wherein the controller 21 is configured or programmed to acquire a first threshold as the reference value, and select a piece of identification information included in a wireless signal Q1 with a corrected received signal strength greater than the first threshold.

With the working vehicle 1 according to item 21, the following is achieved. Even if the distance between the linkage 50 and the attachment 30 stays the same, the received signal strength of the wireless signal Q1 received from the transmitter 33 attached to the attachment 30 increases as the relative distance decreases. Even in this case, the controller 21 is able, by selecting identification information based on the corrected received signal strength and based on the first threshold, to eliminate or reduce the likelihood that attachments 30 located relatively distant from the receiver 23 will be selected, based on the relative position of the linkage 50 relative to the machine body 2. On the contrary, even if the distance between the linkage 50 and the attachment 30 stays the same, the received signal strength of the wireless signal Q1 received from the transmitter 33 attached to the attachment 30 decreases as the relative distance increases. Even in this case, the controller 21 is able, by selecting identification information based on the corrected received signal strength and based on the first threshold, to eliminate or reduce the likelihood that the attachment 30 will not be recognized.

(Item 22) The working vehicle 1 according to any one of items 17 to 20, wherein the controller 21 is configured or programmed to acquire, as a plurality of the reference values, a first threshold and a second threshold greater than the first threshold, and select a piece of identification information included in a wireless signal Q1 with a corrected received signal strength greater than the first threshold and less than or equal to the second threshold.

With the working vehicle 1 according to item 22, since the controller 21 selects identification information based on the corrected received signal strength and based on the first and second thresholds, the controller 21 is able, even if the received signal strength changes as the relative position changes, to appropriately recognize the attachment 30 attached to the linkage 50 by excluding attachments 30 relatively distant from the receiver 23 and distant from the linkage 50 using the first threshold and by excluding attachments 30 located too close to the receiver 23 and distant from the linkage 50 using the second threshold.

(Item 23) The working vehicle 1 according to any one of items 17 to 20, wherein the controller 21 is configured or programmed to acquire a second threshold as the reference value, and select a piece of identification information included in a wireless signal Q1 with a corrected received signal strength less than or equal to the second threshold.

With the working vehicle 1 according to item 23, the following is achieved. Even if the distance between the linkage 50 and the attachment 30 stays the same, the received signal strength of the wireless signal Q1 received from the transmitter 33 attached to the attachment 30 decreases as the relative distance increases. Even in this case, the controller 21 is able, by selecting identification information based on the corrected received signal strength and based on the second threshold, to appropriately determine the attachment 30 attached to the linkage 50. On the contrary, even if the distance between the linkage 50 and the attachment 30 stays the same, the received signal strength of the wireless signal Q1 received from the transmitter 33 attached to the attachment 30 increases as the relative distance decreases. Even in this case, the controller 21 is able, by selecting identification information based on the corrected received signal strength and based on the second threshold, to eliminate or reduce the likelihood that the attachment 30 will not be recognized.

(Item 24) An attachment usage system 100 including a position changer C provided on a machine body 2 of a working vehicle 1, a linkage 50 provided on the position changer C to attach and detach an attachment 30 thereto and therefrom, one or more transmitters 33 provided in or on one or more of the attachments 30 to periodically transmit one or more wireless signals Q1 which include respective one or more pieces of identification information of the one or more attachments 30 and which are compliant with a near field communication standard, a receiver 23 provided in or on the machine body 2 to receive the one or more wireless signals Q1 which are transmitted from the one or more transmitters 33, and a controller 21 configured or programmed to, based on one or more received signal strengths of the one or more wireless signals Q1 received by the receiver 23, select a piece of identification information of the attachment 30 attached to the linkage 50 and perform a predetermined process based on the selected piece of identification information, wherein the position changer C is operable to be driven to change a relative position of the linkage 50 relative to the machine body 2, and the controller 21 is configured or programmed to select, based on a selection condition varying depending on the relative position, a piece of identification information included in a wireless signal Q1 with a received signal strength which satisfies the selection condition.

With the attachment usage system 100 according to item 24, the controller 21 is able to cause the selection condition, based on which identification information is to be selected, to vary depending on the relative position of the linkage 50 relative to the machine body 2. This achieves the following. There may be cases in which, if the relative position of the linkage 50 relative to the machine body 2 (i.e., the relative distance between the receiver 23 in or on the machine body 2 and the transmitter 33 in or on the attachment 30 attached to the linkage 50) changes as the position changer C is driven, the received signal strength of the wireless signal Q1 received by the receiver 23 changes even if the distance between the linkage 50 and the attachment 30 stays the same. Even if this is the case, the controller 21 makes it possible to maintain the accuracy of selecting identification information by causing the selection condition to vary depending on the relative position. It follows that the working vehicle 1 is able to accurately recognize (detect) the attachment 30 attached to the linkage 50 and smoothly perform a predetermined process, making it possible to efficiently use replaceable attachments 30 on the working vehicle 1.

While example embodiments of the present invention have been described above, it is to be understood that variations and modifications will be apparent to those skilled in the art without departing from the scope and spirit of the present invention. The scope of the present invention, therefore, is to be determined solely by the following claims.