EXCAVATION SYSTEM HAVING OPERATOR INITIATED WORK-TOOL SHAKE

Description

TECHNICAL FIELD

The present disclosure relates generally to an excavation system and, more particularly, to an excavation system having operator-initiated work-tool shake.

BACKGROUND

Excavation, mining, or other earth removal activities often employ machines such a wheel loader, track type loaders, trucks etc. move material from a location (e.g., a pile within a mine), haul it to a second location (e.g., to a truck, crusher, stockpile etc.) and dump it there. Productivity of the material removal process depends on the efficiency of a machine during each excavation cycle. For example, the efficiency increases when the machine can sufficiently load a machine tool (e.g., a bucket) with material at the first location within a short amount of time, haul the material via a direct path to the second location, and dump the material at the second location as quickly as possible.

As the machine travels from the first location to the second location, some of the material in the tool may spill from the tool and fall on the machine or along the path travelled by the machine. In some applications, for example, underground mining operations, spillage can create hazardous conditions by creating obstructions in the path of the machine. Because the amount of space available in underground operations is relatively small, cleanup of the spilled material is difficult and may cause reduction in productivity of the machines. Meanwhile, running over spilled material on the path may cause tire damage and other maintenance problems. Moreover, the limited overhead space available in underground operations limits the ability of the operator to lift and tilt the bucket to dump material from the bucket. To avoid spillage, after loading material and dumping material wheel loader operators shake the bucket and shake off any excess material that could fall onto the haul road while travelling.

U.S. Pat. No. 6,757,992 B1 of Berger et al. that issued on Jul. 6, 2004 (“the '992 patent”) describes a method of shaking the implement of a machine in response to the activation of a shaking mode activation switch. When the shaking mode activation switch is depressed, a controller sends a command signal to activate an implement shaking mode. In the '992 patent, the shaking mode switch is either is engaged or not engaged. When the switch is engaged, the controller sends command signals and activates the implement shaking mode. When the switch is not engaged, no command signal is sent, and the machine performs normally. However, shaking the implement merely in response to the activation of a switch without checking the status of implement may stress the hydraulic and linkage systems of the machine and cause damage to these systems.

The excavation system of the present disclosure may solve or reduce this problem and/or other problems of the prior art. However, the scope of the current disclosure is defined by the claims and not on the ability to solve any particular problem.

SUMMARY

In one aspect, a machine is disclosed. The machine may include a work-tool, a lift actuator configured to lift the work-tool above a ground surface, a tilt actuator configured to tilt the work-tool. The machine may also include a controller configured to receive a control signal indicative of an operator command to initiate a work-tool shake routine. The controller may further be configured to execute the work-tool shake routine in response to the control signal based on a comparison of lift actuator extension with a first threshold, and a comparison of tilt actuator extension with a second threshold. The work-tool shake routine may include racking and unracking the work-tool multiple times in succession.

In another aspect, a method of controlling a machine having a work-tool is disclosed. The method may include detecting a first extension of a lift actuator of the machine and detecting a second extension of a tilt actuator of the machine. The lift actuator may be configured to lift the work-tool above a ground surface and the tilt actuator may be configured to tilt the work-tool. The method may also include detecting a control signal indicative of an operator command to initiate a work-tool shake routine and executing the work-tool shake routine in response to control signal based on a comparison of the first extension with a first threshold, and a comparison of the second extension with a second threshold. The work-tool shake routine may include racking and unracking the work-tool multiple times in succession.

In yet another aspect, a wheel loader machine is disclosed. The machine may include a bucket, a lift actuator configured to lift the bucket above a ground surface, a tilt actuator configured to tilt the bucket, a first sensor configured to monitor a first extension of the lift actuator, and a second sensor configured to monitor a second extension of the tilt cylinder. The machine may also include an input device configured to generate a control signal indicative of input from an operator to initiate a bucket-shake routine. The machine may further include a controller in communication with the first sensor, the second sensor, and the input device. The controller may be configured to execute the bucket-shake routine in response to the control signal when the first extension is less than a first threshold and the second extension is greater than a second threshold. The bucket-shake routine may include racking and unracking the bucket multiple times in succession.

In yet another aspect, a non-transitory computer readable medium that stores a set of instructions that is executable by at least on processor of a computing device to cause the computing device to perform operations for controlling a machine having a work-tool is disclosed. The operations may include detecting a control signal indicative of an operator command to initiate a work-tool shake routine. The operations may also include detecting a first extension of a lift actuator of the machine and detecting a second extension of a tilt actuator of the machine. The lift actuator may be configured to lift the work-tool above a ground surface and the tilt actuator may be configured to tilt the work-tool. The operations may also include executing the work-tool shake routine in response to the control signal based on a comparison of the first extension with a first threshold, and a comparison of the second extension with a second threshold. The work-tool shake routine may include racking and unracking the work-tool multiple times in succession.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side-view illustration of an exemplary disclosed machine;

FIGS. 2A-2C are illustrations of an exemplary machine operating at an exemplary disclosed worksite;

FIG. 3 is an illustration of an exemplary operator cabin of the machine of FIG. 1;

FIG. 4 is a block diagram of an exemplary controller of the machine of FIG. 1;

FIGS. 5-8 are flowcharts illustrating exemplary methods for performing work-tool shake in the machine of FIG. 1.

DETAILED DESCRIPTION

FIG. 1 illustrates an exemplary machine 10 in some embodiments of the current disclosure. The machine illustrated in FIG. 1 is a wheel loader. However, this is only exemplary and machine 10 may, in general, be any type of construction or excavation machine (e.g., a hydraulic excavator, a track loader, etc.) used in any type of application (underground, overground, etc.). Machine 10 may include, among other things, a power source 12, one or more traction devices (e.g., wheels 14), a work-tool (e.g., a bucket 16), one or more lift cylinders or lift actuators 18, and one or more tilt cylinders or tilt actuators 20. Lift actuators 18 and tilt actuators 20 may connect bucket 16 to frame 22 of machine 10. In one exemplary embodiment as illustrated in FIG. 1, lift actuators 18 may have one end connected to frame 22 and an opposite end connected to a structural member 24, which may be connected to bucket 16. Bucket 16 may be connected to structural member 24 via pivot pin 26. Lift actuators 18 may be configured to lift or raise bucket 16 to a desired height above ground surface 28. In some exemplary embodiments, as illustrated in FIG. 1, tilt actuators 20 may have one end connected to frame 22 and an opposite end connected to linkage member 30, which may be connected to bucket 16. Tilt actuators 20 may be configured to alter an inclination of a lower surface 32 of bucket 16 relative to ground surface 28.

Power source 12 may be supported by a frame 22 of machine 10 and may include an engine or an electric motor (not shown) configured to produce a rotational power output and a transmission (not shown) that converts the power output to a desired ratio of speed and torque. The rotational power output may be used to drive an electric or hydraulic system 80 (see FIG. 4) that supplies power (e.g., pressurized fluid, current, etc.) to lift actuators 18, tilt actuators 20, and/or to one or more motors (not shown) associated with wheels 14. In some embodiments, the engine of power source 12 may be a combustion engine configured to burn a mixture of fuel and air, the amount and/or composition of which directly corresponding to the rotational power output. The transmission of power source 12 may take any form known in the art, for example a power shift configuration that provides multiple discrete operating ranges, a continuously variable configuration, or a hybrid configuration. Although power source 12 is described as an internal combustion engine. This is only exemplary. In general, any now-known or future-developed power source for a machine may be used. For example, in some embodiments, power source 12 may be one or more electric motors powered by, for example, batteries, fuel cells, etc. Power source 12, in addition to powering the hydraulic (or another) system that moves bucket 16, may also function to propel machine 10, for example via one or more traction devices (e.g., wheels) 14.

Although the work-tool of machine 10 is described as a bucket (i.e., bucket 16), this is only exemplary. Numerous different types of work-tools may be operatively attachable to a single machine 10 and driven by power source 12. The work-tool(s) attached to machine 10 may include any device used to perform a particular task such as, for example, a bucket, a fork arrangement, a blade, a shovel, the lift bed of a truck (e.g., with linkages or other mechanisms to raise and lower the bed), or any other task-performing device known in the art. Although bucket 16 is connected to machine 10 in the embodiment of FIG. 1 to lift and tilt relative to machine 10, bucket 16 may alternatively or additionally rotate, slide, swing open/close, or move in any other manner known in the art. Lift and tilt actuators 18, 20 may be extended or retracted to repetitively move bucket 16 between different configurations during an excavation cycle. In an exemplary embodiment where the lift bed of a truck is the work-tool, the lift cylinder may be extended or retracted repetitively to move the bed in a similar manner to the bucket on the wheel loader.

An exemplary excavation cycle of an underground wheel loader (machine 10) will be described with reference to FIGS. 2A-2C. The excavation cycle may be associated with removing material from a material pile 34 inside of a mine tunnel 36 (see FIG. 2B) and dumping the removed material in another material pile (e.g., stockpile 134 of FIG. 2C). Material pile 34 may constitute a variety of different types of materials. In general, material pile 34 (and stockpile 134) may consist of any material. For example, in a mining operation, material pile 34 may consist of mining materials, such as, for example, ore, clay, rock, debris, mineral formations, etc. To begin an exemplary excavation cycle, the operator of machine 10 may position the machine near material pile 34. Machine 10 may use its front-mounted bucket 16 to scoop up the material from pile 34. Bucket 16 may include a tip 38 configured to penetrate the material pile 34 and collect some of the material from material pile 34 in bucket 16. The operator may lift the loaded bucket 16 using the lifting mechanism (e.g., lift actuators 18, tilt actuators 20, etc.) to clear the ground and prepare for transporting the collected material to stockpile 134. The travel of an underground wheel loader machine (e.g., machine 10) from one location to another, within a mine is typically referred to as tramming.

FIG. 2B illustrates an exemplary machine 10 with its bucket 16 loaded with material in preparation for tramming. In the current disclosure, the configuration of bucket 16 with its lower surface 32 making a positive angle (+θ) with the horizontal axis (e.g., ground surface 28), as illustrated in FIG. 2B, will be referred to as the tramming configuration of bucket 16. With bucket 16 in the tramming configuration, machine 10 may move to the location of stockpile 134 carrying the loaded bucket 16. Once machine 10 reaches stockpile 134, the operator may raise the loaded bucket to an appropriate height and tilt the bucket to dump the material stored in the bucket into stockpile 134. FIG. 2C illustrates an exemplary machine 10 with its bucket 16 tilted to dump the material. In the current disclosure, the configuration of bucket 16 with its lower surface 32 making a negative angle (−θ) with the horizontal axis (e.g., ground surface 28), as illustrated in FIG. 2C, will be referred to as the dumping configuration of bucket 16. Moving (or tilting) bucket 16 towards its tramming and dumping configurations may be referred to as racking and unracking the bucket. Bucket 16 may be racked and unracked by selectively extending and retracting lift and tilt actuators 18, 20. After dumping the material on stockpile 134, machine 10 may return to material pile 34 to repeat the loading and dumping cycle until the required amount of material has been moved from pile 34 to stockpile 134. It should be noted that reference to material pile 34 and stockpile 134 are merely exemplary. In general, machine 10 may be used to move material between any two locations.

Machine 10 may include a variety of sensors to enhance the operational efficiency, ensure safety, and monitor the performance of the machine. These sensors may include proximity sensors (e.g., ultrasonic or radar sensors) to detect obstacles in the vicinity of machine 10, position sensors (e.g., angle sensors, extension sensors, inclinometers, etc.) to monitor the orientation and position of various components (e.g., bucket, boom, chassis, etc.), load sensors to measure the weight of the material in the bucket, speed sensors to monitor the speed of machine 10 during tramming or other movements, tilt sensors or inclinometers to detect the tilt or angle of machine 10, temperature sensors to monitor the operating temperature of various components (e.g., engine, transmission, hydraulic systems, etc.), pressure sensors to detect the pressure of different components in the hydraulic system, camera systems and navigation sensors to assist in navigation.

For example, machine 10 may include, among other sensors, distance sensor 40, speed sensor 50, load sensors 52, lift sensor 56, tilt sensor 58, lift pressure sensor 60, and tilt pressure sensor 62 (see FIG. 4). Any type of sensor suitable to detect or sense the parameter being measured may be used as distance sensor 40, speed sensor 50, load sensor 52, lift sensor 56, tilt sensor 58, lift pressure sensor 60, and tilt pressure sensor 62. For example, distance sensors 40 may be configured to determine a distance of machine from material pile 34 and/or stockpile 134. Any sensor (e.g., LIDAR, RADAR, SONAR, etc.) configured to measure the distance of the machine from material pile 34 and/or stockpile 134 may be used as sensor 40. Speed sensor 50 may detect the speed of machine 10. Any sensor configured to measure speed may be used as speed sensor 50. For example, in some embodiments, speed sensor 50 may a rotational speed detector configured to sense a relative rotational movement of wheel 14 (or a rotating portion of power source 12 that is operatively connected to wheel 14). Load sensor 52 may be any type of sensor (e.g., load cell, pressure sensor, etc.) capable of generating a signal indicative of an amount of load exerted on bucket 16 (e.g., by material in the bucket). In some embodiments, load sensor 52 may be a torque sensor configured to detect a change in torque output of power source 12 due to a load on bucket 16. In some embodiments, lift sensor 56 and tilt sensor 58 may be configured to detect an extension (or length of extension) or position of lift actuator 18 (or an associated lift cylinder) and tilt actuator 20 (or an associated tilt cylinder), respectively. Sensors, such as, for example, linear position sensors, encoder sensors, linear variable differential transformer (LVDT) sensors, pressure transducers, magnetostrictive-type sensors, etc. may be used as the lift and tilt sensors. In some embodiments, lift and tilt sensors may be magnetic pickup-type sensors associated with a magnet (not shown) embedded within the lift and tilt actuators 18, 20. Lift pressure sensor 60 may be located within lift actuators 18 to sense a pressure of the fluid therein. Likewise, tilt pressure sensors 62 may be located within tilt actuator(s) 20 to sense the pressure of the fluid therein. It should be noted that although the activation of a disclosed bucket shaking routine (also referred to herein as a bucket-shake routine) is described (later) as being activated based on the extension of the lift and tilt cylinders, this is only exemplary. In general, a disclosed bucket-shake routine may be activated or controlled based on signals from any sensor (e.g., distance sensor 40, speed sensor 50, load sensor 52, lift sensor 56, tilt sensor 58, lift pressure sensor 60, and tilt pressure sensor 62, or any other sensor) of machine 10.

Machine 10 may also include a variety of operator control devices (e.g., knobs, buttons, levers, etc.) that enable an operator to control machine 10 and its components (e.g., bucket 16, etc.). When machine 10 is controlled by an operator located (e.g., seated) in machine, these control devices may be located in the operator cabin of machine. When machine 10 is controlled remotely, these control devices may be located at a remote site (e.g., at a remote-control facility). In some embodiments, some control devices may be locally located in the operator cabin of the machine, and some control devices may be remotely located at a central site, for example, to enable both a locally located operator and a remotely located operator to control machine 10. FIG. 3 illustrates an exemplary operator cabin 70 of machine 10 (see also FIG. 1). As illustrated in FIG. 3, operator cabin 70 may include multiple control devices (e.g., buttons, knobs, switches, joysticks, etc.) that may be used by the operator to control the operation of machine 10, its components, and its work-tools (e.g., bucket 16).

These multiple control devices include, for example, a joystick 72 that may be used by the operator to manipulate and control the movement and functions of machine 10. For example, in some embodiments, joystick 72 may be used to control the movement (e.g., raising, lowering, racking, unracking, etc.) of bucket 16. In some embodiments, joystick 72 may also control the movement of the boom and arm of machine 10. In some embodiments, joystick 72 may also be used to control the tramming or movement of machine 10. In some embodiments, joystick 72 maybe also be used to control the hoist (raising and lowering) of a truck bed. Joystick 72 may include one or more operator control devices (buttons, switches, triggers, etc.) thereon.

Among other control devices, joystick 72 may include a trigger 74 that may be used (e.g., pressed) by the operator to control one or more movements of bucket 16. For example, in some exemplary embodiments, the operator may press trigger 74 to initiate/activate a bucket-shake routine as will be described in more detail below. In some embodiments, the bucket-shake routine will be activated when trigger 74 is pressed. In some embodiments, the operator may press and hold trigger 74 for a predetermined time (a threshold value of time, e.g., x seconds, where x is any value of time) to activate a bucket-shake routine. In some embodiments, the bucket-shake routine will be activated if, after the operator presses trigger 74, one or more threshold conditions are met (e.g., one or more sensor readings meet predetermined threshold conditions, etc.). In some exemplary embodiments, once activated (e.g., by a trigger press), the bucket-shake routine will continue as long as the trigger is kept pressed. In some embodiments, once activated, the bucket-shake routine will continue for a predetermined (or preprogrammed) time and then stop. Although described as a trigger located in machine 10, any type of control device (e.g., switch, button, etc.) may be configured to initiate a bucket-shake routine, and the control device (configured to activate the bucket-shake routine) may be located in machine 10 (as illustrated in FIG. 3) or at a remote location away from machine.

It should be noted that the operator pressing a switch (e.g., trigger 74) or activating a control device to initiate a bucket-shake routine is only exemplary. In general, the operator may indicate his or her wish to initiate or activate a bucket-shake routine in any manner. For example, in some embodiments, the bucket-shake routine may be initiated upon a gear shift (e.g., upon detection of gear change from forward to reverse, reverse to forward, or another gear change). In some embodiments, the bucket-shake routine may be initiated based on direction change in transmission and/or a change in the velocity of the machine. As another example, the bucket-shake routine may be initiated via a remotely located switch or another device (e.g., a smart phone, etc.). For example, a signal received by controller 44 from a location remote from machine 10 via communication device 46 may activate/initiate a bucket-shake routine. In other words, the signal indicative of an operator command to initiate a bucket-shake routine may be generated in any manner (switch press, signal from a remote location, based on a change in the drive system of machine, based on a change in the transmission, based on a velocity change, or based on another change in machine operation).

The sensors (e.g., distance sensor 40, speed sensor 50, load sensor 52, lift sensor 56, tilt sensor 58, lift pressure sensor 60, tilt pressure sensor 62, etc.) and input devices (e.g., trigger 74) of machine 10 may send corresponding signals to a controller 44. Based on the signals received, controller 44 may control the operation (e.g., excavation cycle) of machine 10 and its components (e.g., bucket 16). FIG. 4 is a schematic illustration of an exemplary controller 44 of machine 10. Controller 44 may include circuitry configured to automatically determine various operational parameters of machine 10 and control the operation of machine 10 and its components to improve efficiency of machine 10 during the excavation cycle. Controller 44 may be operatively coupled to the sensors (e.g., distance sensor 40, speed sensor 50, load sensor 52, lift sensor 56, tilt sensor 58, lift pressure sensor 60, tilt pressure sensor 62, etc.), control devices (e.g., trigger 74), and other components (e.g., hydraulic system 80, communication device 46, etc.) of machine 10. Controller 44 may be configured to send and receive signals from these connected devices/systems to control various functions of machine 10.

Controller 44 may embody a single microprocessor or multiple microprocessors and include circuitry configured to monitor and control the operations of machine 10, communicate with a remote (or off-board) entity, and receive instructions/signals from the remote entity. For example, controller 44 may include a memory, a secondary storage device, a clock, and a processor, such as a central processing unit or any other device for accomplishing a task consistent with the present disclosure. The memory or secondary storage device associated with controller 44 may store data and/or algorithms, routines, instructions, or software code to assist controller 44 in performing its functions. Further the memory or storage device associated with controller 44 may also store data received from the sensors and control devices of machine 10. It should be appreciated that controller 44 could readily embody a general machine controller capable of controlling numerous other machine functions. Various other known circuits may be associated with controller 44, including signal-conditioning circuitry, communication circuitry, hydraulic or another actuation circuitry, and other appropriate circuitry.

Communication device 46 may include hardware and/or software that enables the sending and/or receiving of data through a communications link. The communications link may include satellite, cellular, infrared, radio, and/or any other type of wireless communications. Alternatively, the communications link may include electrical, optical, or any other type of wired communications. For example, in some embodiments, communication device 46 may include two-way radio systems allow the operator of machine 10 to communicate with personnel at a remote site. In some embodiments, communication device 46 may include wireless communication technologies (e.g., Wi-Fi or other wireless protocols) to enable the transfer of data (e.g., operational data, machine diagnostics, and receiving commands) between machine 10 and, for example, a remote-control center. In some embodiments, communication device 46 may include telemetry systems that enable remote monitoring and control of machine 10 through wireless communication. These systems may transmit real-time data about machine status, performance, and location. In some embodiments, communication device 46 may use satellite communication to establish a reliable link between machine 10 and a remote-control center. In some embodiments, communication device 46 may use Bluetooth technology or Radio-Frequency Identification (RFID) technology for short-range communication (e.g., for proximity detection and tracking) between machine 10 and nearby devices or infrastructure. In some embodiments, on-board controller 44 may be omitted, and an off-board controller (not shown) may communicate directly with the sensors, control devices, and other components (as illustrated in FIG. 4) of machine 10 via communication device 46.

Hydraulic system 80 may include, among other components, hydraulic cylinders, pumps, valves, and a reservoir of hydraulic fluid. Hydraulic system 80 may generate and control hydraulic pressure to perform various functions of machine 10. In some embodiments of machine 10, the lifting mechanism (e.g., lift actuator 18, tilt actuator 20, etc.) of bucket 16 may be powered by hydraulic system 80. For example, hydraulic system 80 may control the movement of bucket 16 for lifting, lowering, tilting, and dumping operations. In an exemplary embodiment, the lift and tilt actuators of hydraulic system 80 may be hydraulic cylinders connected to the lifting arms (or structure) of machine 10. These cylinders may extend and retract based on hydraulic pressure, causing the lifting arms to move and lift bucket 16. It should be noted that although a hydraulic system is described, this is only exemplary. In general, machine 10 may include any mechanism to operate bucket 16. For example, in some embodiments, an exemplary machine may include an electrical system (e.g., with electric motor, electric actuators, etc.) that may operate bucket 16.

The operator may control the lifting function using control devices, such as, for example, joystick 72. By manipulating these control devices, the operator may send a signal to controller 44 to extend or retract the lift cylinders. In response to this signal from the operator, controller 44 may command hydraulic system 80 to extend or retract the lift and/or the tilt actuators 18, 20. For example, when the operator commands the lifting of bucket 16, hydraulic system 80 may cause the hydraulic fluid to be pressurized by the hydraulic pump and directed to the lift cylinders causing them to extend. The extension of the lift cylinders raises bucket 16. Similarly, when the operator commands the racking or unracking of bucket 16, hydraulic system 80 causes pressurized hydraulic fluid to be directed to, or drained from, the lift and tilt cylinders causing bucket 16 to rotate (or tilt) in the desired direction.

Based on the signals from the sensors and the control devices operatively coupled to controller 44, the controller may send control signals to hydraulic system 80 (and/or other components) of machine 10 to control the operation of machine 10 (e.g., activate and deactivate selected functions). For example, based on signals received from the sensors of machine 10, controller 44 may, among other things, determine the configuration of bucket 16 at any time during the excavation cycle, and control the operation of machine 10. For example, controller 44 may calculate a height of bucket 16 above ground surface 28. As another example, based on known geometry and/or kinematics of frame 22, lift actuators 18 and tilt actuators 20, and other connecting components of machine 10, controller 44 may be configured to calculate tip angle “θ,” representing an angle of inclination of lower surface 32 of bucket 16 relative to ground surface 28. When bucket 16 along with its lower surface 32 tilts away from the ground surface 28 towards its tramming configuration (see FIG. 2B), angle θ increases in the positive direction (in other words, angle θ is positive). And when bucket 16 along with its lower surface tilts towards the ground surface 28 towards its dumping configuration (see FIG. 2C), angle θ increases in the negative direction (or angle θ is negative). Tilting bucket 16 away from the ground surface 28 may be referred to as racking the bucket, and tilting bucket 16 towards the ground surface 28 may be referred to as unracking the bucket.

When controller receives a signal indicative of an operator command to initiate a bucket-shake routine, based on additional inputs from one or more other sensors, controller 44 may activate the bucket-shake routine. For example, upon receipt of the signal indicative of operator command to initiate a bucket-shake routine, controller 44 may check the signals received from one or more sensors to determine if one or more other condition(s) are met and activate the bucket-shake routine if those conditions are also met. For example, in some exemplary embodiments of the current disclosure, when controller 44 receives a signal from trigger 74, controller 44 determines the configurations of the lift and tilt actuators 18 and 20 (based on sensor signals) to determine if their configurations satisfy predetermined conditions, and if these conditions are satisfied, activates a bucket-shake routine to shake bucket 16. In some embodiments, if the lift and tilt actuator configurations satisfy a first set of conditions, the controller activates a first bucket-shake routine (referred as a settling-shake routine in the description below), and if their configurations satisfy a second set of conditions, the controller activates a second bucket-shake routine (referred as a dumpout-shake routine in the description below). These bucket-shake routines may be activated by sending command signals to hydraulic system 80 to manipulate, for example, lift and tilt actuators 18 and 20 to cause bucket 16 to rack and unrack multiple times in succession. The above-described first and second bucket-shake routines may be similar to each other or different from each other.

In general, controller 44 may activate any number of bucket-shake routines based on a signal indicative of an operator command to activate a bucket-shake routine. In general, upon receipt of a signal indicative of an operator command to activate a bucket-shake routine, controller 44 may compare the signals received from one or more sensors of machine 10 to predetermined threshold conditions and activate a bucket-shake routine based on this comparison (e.g., if the threshold conditions are met). For example, controller 44 may activate a first bucket-shake routine if a first threshold condition is met, activate a second bucket-shake routine if a second threshold condition is met, activate a third bucket-shake routine if a third threshold condition is met, etc.

In some embodiments, controller 44 may select or vary a characteristic (type, extent, duration, frequency, severity, etc.) of the bucket-shake routine based on sensor readings. For example, in the first bucket-shake routine, controller 44 may rack and unrack bucket 16 a preset number of times (e.g., once, twice, thrice, five times, ten times, etc.) and then stop, in the second bucket-shake routine controller 44 may rack and unrack bucket repeatedly or continuously until another condition is met. For example, controller 44 may continuously rack and unrack bucket 16 until a second signal indicative of an operator command to stop the bucket-shake routine is received, until the first signal indicative of an operator command to activate the bucket-shake routine stops or ceases, based on a comparison of a sensor signal with another threshold, etc. Alternatively, or additionally, in some embodiments, the frequency (e.g., the speed) at which the bucket racks and unracks during a bucket-shake routine may also be based on a sensor signal. For example, in the first bucket-shake routine, controller 44 may rack and unrack bucket 16 a first preset frequency, and in the second bucket-shake routine, controller 44 may rack and unrack bucket 16 a second preset frequency.

FIGS. 4-8 illustrate exemplary methods that may be performed by controller 44 to perform a bucket-shake routine. It should be noted that the illustrated methods are merely exemplary, and many variations are possible. These methods will be discussed in more detail in the following section to further illustrate the disclosed concepts.

INDUSTRIAL APPLICABILITY

The disclosed excavation system may be used to improve the efficiency of the excavation process of any locally or remotely controlled machine (e.g., any type of construction or excavation machine, such as, for example, a hydraulic excavator, a track loader, etc.). In general, a bucket-shake routine may be activated at any time during the excavation process. For example, in an exemplary application on a underground wheel loader machine with a bucket as its work-tool, the controller of the machine may improve the efficiency of the excavation process by executing a first bucket-shake routine (e.g., a settling-shake routine) upon operator activation by shaking the bucket after filling material from a material pile to ensure that loose material falls out of the bucket onto the material pile before the machine withdraws from the material pile to travel to a dump location (e.g., a stockpile). The controller may further improve the efficiency of the excavation process by executing a second bucket-shake routine (e.g., a dumpout-shake routine) upon operator activation by shaking the bucket after dumping material from the bucket to a stockpile ensure all material is dumped out of the bucket before the machine withdraws from the stockpile. The settling-shake routine and the dumpout-shake routine may cause the bucket to rack and unrack multiple times in succession. It should be noted that executing a bucket-shake routine after loading material into the bucket and after unloading material from the bucket are merely exemplary. As explained previously, a bucket-shake routine may be activated and executed at any time during the excavation process (e.g., during driving from the material pile to the dump site, etc.).

Operation of controller 44 executing the above-described exemplary settling-shake and dump-out shake routines will now be described with reference to FIGS. 5 and 6. FIG. 5 is a flow chart that illustrates an exemplary method 500 of performing a settling-shake routine by controller 44 of machine 10. In step 510, bucket 16 may be operated to load material from material pile 34 (see FIG. 2A) into bucket 16. Bucket 16 may be loaded with material from material pile 34 in any known manner. For example, in some embodiments, this step may include positioning machine 10 in proximity to material pile 34. Bucket 16 may then be lowered to ground level and machine 10 may be moved towards material pile 34 while aligning bucket 16 with the desired region of material pile 34. Control devices (levers, buttons, joysticks, etc.) may then be activated to engage bucket 16 with material pile 34. This may involve using the control devices to control the movements of the bucket arms and penetrate bucket 16 into material pile 34. With bucket 16 in material pile 34, the bucket may be raised to scoop up the material from pile 34 into bucket 16.

In some embodiments, step 510 may include engaging the auto-load digging functionality of machine 10. The auto-load digging functionality may help ensure that sufficient amount of material is loaded in bucket 16. Controller 44 may initiate the auto-load digging functionality in response to a variety of inputs. For example, controller 44 may automatically initiate auto-load digging in response to a detection of forward travel (e.g., in response to a signal from speed sensor 50). In another example, controller 44 may initiate auto-load digging in response to a proximity to material pile 34 (e.g., in response to a signal from sensor 40). In yet another example, auto-loading may be initiated manually by a local or remote operator. Any combination of these inputs (and others) may be utilized to initiate auto-load digging functionality.

In some embodiments, step 510 may include a step of detecting pile impact, for example, detecting contact of bucket 16 with material pile 34. In one exemplary embodiment, controller 44 may orient bucket 16 so that lower surface 32 of bucket 16 is disposed generally parallel to ground surface 28. As machine 10 travels towards material pile 34 with bucket 16 disposed generally parallel to ground surface 28, controller may receive signals from various components of machine 10. Controller 44 may detect contact of bucket 16 with material pile 34 based on a sharp change in acceleration of machine 10. Alternatively or additionally, controller 44 may detect a slowing down of machine 10 by detecting a sharp change in torque output of power source 12 (i.e., by an increase in torque output). Accordingly, controller 44 may continuously compare monitored values of torque output and acceleration to respective threshold values to detect engagement of bucket 16 with material pile 34. In some embodiments, to operate bucket 16 in step 510, controller 44 may issue commands to one or more lift actuators 18 and tilt actuators 20 to lift bucket 16 and rack and unrack bucket 16 as bucket 16 penetrates material pile 34. By actuating lift actuators 18 and tilt actuators 20 in this manner, controller 44 may help ensure that material from material pile 34 is removed and loaded into bucket 16.

In step 520, controller 44 may determine whether loading of bucket 16 with material from material pile 34 is complete. Controller 44 may determine whether loading of bucket 16 is complete in any manner. For example, in some embodiments, controller 44 may determine that loading of bucket 16 is complete when a height of pivot pin 26 above ground surface 28 exceeds a target height. Alternatively or additionally, controller 44 may determine that loading of bucket 16 is complete when an amount (e.g., weight) of material in bucket 16 exceeds a target amount. In some embodiments, controller 44 may determine that loading of bucket 16 is complete when tip 38 has penetrated material pile 34 by a distance that exceeds a target penetration distance. In some embodiments, controller 44 may determine that loading of bucket 16 is complete when a tip angle exceeds a tip angle target and/or when it detects that tip 38 of bucket 16 has been extracted from material pile 34. When controller 44 determines that loading of bucket 16 is not complete (step 520: No), controller 44 may return to step 510 to continue operating bucket 16 to load bucket 16 with material. Thus, controller 44 may cycle through steps 510 and 520 to continuously monitor whether loading of bucket 16 is complete as bucket 16 is loaded with material. When controller 44 determines, however, that loading of bucket 16 is complete (step 520: Yes), controller proceeds to step 530. In embodiments where a bucket-shake routine (e.g., step 560) is activated at a different stage of the excavation process (e.g., during driving to the dump site after loading), steps 510 and 520 may be eliminated.

In step 530, controller 44 determines whether it has received a signal that indicates that the operator wishes or intends to initiate a bucket-shake routine (e.g., of step 560). As explained previously, the signal that indicates an operator command to initiate a bucket-shake routine may be generated in any manner (switch press, signal from a remote location, based on a change in the drive system of machine, based on a change in the transmission, based on a velocity change of machine, or based on another change in machine operation). In an exemplary embodiment, in step 530, controller 44 determines if trigger 74 of joystick 72 (see FIG. 3) is pressed. As previously explained, checking whether trigger 74 is pressed is only exemplary. In embodiments where another (local or remote) control device is used to activate a bucket-shake routine (e.g., of step 560), controller 44 determines whether that control device is activated. Controller 44 may determine whether trigger 74 (or another control device) is pressed based on a signal received from the trigger (or control device). In some embodiments, in step 530, controller 44 may determine if trigger 74 is pressed and held (e.g., kept pressed) for a predetermined time (a threshold value of time, e.g., x seconds, where x is any value of time). If controller 44 determines that trigger 74 is not pressed (step 530: No), the controller 44 may proceed to (or instruct) withdraw machine 10 from material pile 34 (or continue with normal operation of machine 10). In other words, if trigger 74 is not pressed, controller 44 may infer that the bucket-shake routine is not needed (e.g., the operator believes that material from the bucket will not spill) and may prepare to withdraw from material pile 34 to travel to the site of stockpile 134 and dump the loaded material. If controller 44 determines that trigger 74 of joystick 72 is pressed (step 530: Yes), controller 44 proceeds to step 540.

In step 540, controller 44 may determine if the extension of lift actuator 18 is less than a first threshold value. As explained previously, lift actuator 18 controls the vertical movement (e.g., raising, lowering, etc.) of bucket 16. The extension of lift actuator 18 may be directly related to the vertical position of bucket 16. When lift actuator 18 extends, it lifts bucket 16, raising it to a higher position. The extension of lift actuator 18 is a measure of how far the lift actuator has moved to elevate bucket 16. The first threshold value may be any selected value of lift actuator extension that corresponds to the desired vertical position of bucket (or bucket height). In some embodiments, the first threshold value may be selected as the lift actuator extension that corresponds to between about 20-30% of the maximum bucket height. For example, if the maximum bucket height of machine 10 is H, in some embodiments, the first threshold value may be selected as the lift cylinder extension that results in a bucket height between about 0.2-0.3 H. It should be noted that this range of values is only exemplary, and in general, the first threshold value may be any predetermined (or preselected) value of lift actuator extension. If controller 44 determines that the lift actuator extension is not less than the preselected first threshold value (step 540: No), controller 44 may proceed to (or instruct) withdraw machine 10 from material pile 34 (i.e., step 570). If controller 44 determines that the lift actuator extension is less than the first threshold value (step 540: Yes), controller 44 proceeds to step 550.

In step 550, controller 44 determines if the extension of tilt actuator 20 is greater than a second threshold value. As explained previously, tilt actuator 20 is responsible for controlling the tilting motion of bucket 16, allowing it to tip forward or backward. The tilt actuator extension provides information about the position of the tilt actuator and, by extension, the tilt angle of bucket 16. In general, any value of tilt actuator extension that corresponds to the desired bucket configuration or tilt angle may be preselected as the second threshold value. In some embodiments, the second threshold value may be selected as the extension of the tilt actuator 20 that results in bucket 16 being a partially racked configuration. In some embodiments, when extension of lift actuator 18 is less than the first threshold value and the extension of tilt actuator 20 is greater than the second threshold value, bucket 16 may be in the tramming configuration illustrated in FIG. 2B. If controller 44 determines that the tilt actuator extension is not greater than the second threshold value (step 550: No), controller 44 may proceed to (or instruct) withdraw machine 10 from material pile 34 (i.e., step 570). If controller 44 determines that the tilt actuator extension is greater than the second threshold value (step 550: Yes), controller 44 proceeds to step 560.

In step 560, controller 44 may execute a bucket-shake routine (referred to herein as the settling-shake routine) on bucket 16. An exemplary settling-shake routine that may be executed by controller 44 will be described with reference to FIG. 7. In this step, controller 44 may shake bucket 16 to cause any loose material in bucket 16 to spill out onto material pile 34. Controller 44 may shake bucket 16 by racking and unracking bucket 16 multiple times in quick succession. In one exemplary embodiment, controller 44 may rack and unrack bucket 16 at least 2 times in step 560. In general, in this step, controller 44 may rack and unrack bucket 16 about 2-10 times in rapid succession. The process of shaking bucket 16 in some embodiments of step 560 will be discussed below with respect to FIG. 7.

In some embodiments, after executing the settling-shake routine (of step 560), controller 44 may return to step 530 to determine if trigger 74 is still pressed (i.e., step 530: Yes). If it is, controller 44 may continue to execute the settling-shake routine of step 560 if the conditions of steps 540 and 550 continue to be met (i.e., if the extension of the lift actuator 18 is below the first threshold value and the extension of tilt actuator 20 is above the second threshold value). It the conditions of any of steps 530, 540, or 550 are no longer met, controller 44 may stop executing the settling-shake routine of step 560 and proceed to step 570.

In some embodiments, controller 44 may execute the settling-shake routine of step 560 for a predetermined amount of time and then proceed to step 570 without going back to check if trigger 74 is still pressed as shown in FIG. 5. For example, in step 530, controller 44 may determine if trigger 74 is kept pressed for the threshold value of time (e.g., any predetermined extent of time). And if trigger 74 is kept pressed for the threshold value of time, and the conditions of steps 540 and 550 are met, controller 44 may execute the settling-shake routine of step 560 for a predetermined amount of time and then proceed to step 570.

In step 570, controller 44 may cause machine 10 to withdraw from material pile 34. After withdrawing from material pile 34, machine 10 may proceed along a designated path to the location of stockpile 134 (see FIG. 2C) to dump the contents of bucket 16 on stockpile 134. By shaking bucket 16 before withdrawing machine 10 from material pile 34, method 500 may help ensure that loose material from bucket 16 is spilled on material pile 34 for pickup by machine 10 during a subsequent excavation cycle. Further, by helping ensure that loose material from bucket 16 is spilled on material pile 34, method 500 may help ensure that loose material does not spill along the path from material pile 34 to stockpile 134. This in turn may help to keep the path clear of debris and reduce and/or eliminate the need to clean the path of any spillage from bucket 16 as machine 10 travels on the path. As with steps 510 and 520, in embodiments where a bucket-shake routine (e.g., step 560) is activated at a different stage of the excavation process (e.g., during driving to the dump site after loading), step 570 may also be eliminated.

When machine 10 reaches stockpile 134, it may dump out the material stored in bucket 16 on stockpile 134 and return to material pile 34 to collect more material. After dumping out the material on stockpile 134, controller 44 may execute a further bucket-shake routine (referred to herein as the dumpout-shake routine) on bucket 16 to ensure that all the material is dumped out of bucket 16 onto stockpile 134 before proceeding to material pile 34 to collect more material. Executing the dumpout-shake routine may help stuck material in bucket 16 to be dislodged onto stockpile 134 and ensure that it does not fall on the path from stockpile 134 back to material pile 34.

FIG. 6 is a flow chart that illustrates an exemplary method 600 of performing a dumpout-shake routine by controller 44 of machine 10. In step 610, controller 44 may operate bucket 16 to dump the material from bucket 16 to stockpile 134 (see FIG. 2C). This step may involve positioning machine 10 with bucket 16 positioned near stockpile 134. Bucket 16 may then be positioned such that the material in the bucket can be easily dumped onto stockpile 134. Control devices of machine 10 may then be operated to tilt bucket 16 and start the dumping process. In some embodiments, the tilt of bucket 16 may be adjusted during the dumping process to control the flow of material out of the bucket.

In step 620, controller 44 determines whether the dumping process is complete. Controller 44 may determine if the dumping process is complete through various sensing mechanisms and feedback systems. For example, in some embodiments, based on sensor inputs that indicate the tilt angle and the height of bucket 16, controller 44 may recognize when the bucket has reached a specific position indicative of the completion of the dumping process. In some embodiments, load sensors may be installed to measure the weight or load in bucket 16. As material is dumped, the weight decreases. Controller 44 may use this information to infer whether the material has been completely discharged from bucket 16. In some embodiments, pressure sensors in the hydraulic system may provide information about the hydraulic pressure that is indicative an empty bucket. In some embodiments, controller 44 may infer that all the material stored in bucket 16 has been discharged based on signals from lift and tilt actuators 18, 20. If the dumping process is not complete (step 620: No), controller 44 may continue to operate bucket 16 to dump material from the bucket (step 610). If the dumping process is complete (step 620: Yes), controller 44 may move to step 630.

In step 630, controller 44 determines if trigger 74 of joystick 72 (see FIG. 3) is pressed. As previously explained, checking whether trigger 74 is pressed is only exemplary. In general, in this step, controller 44 may determine if it has received a signal that indicates that the operator intends to initiate a bucket-shake routine (e.g., of step 660). Controller 44 may determine whether trigger 74 is pressed based on a signal received from trigger 74. In some embodiments, in step 630, controller 44 may determine if trigger 74 is pressed and held (e.g., kept pressed) for a predetermined time (a threshold value of time, e.g., x seconds, where x is any value of time). If controller 44 determines that trigger 74 is not pressed (step 630: No), the controller 44 may proceed to (or instruct) withdraw machine 10 from stockpile 134 (step 670). In other words, if trigger 74 is not pressed, controller 44 may infer that the bucket-shake routine is not needed (e.g., the operator believes that all the material in bucket 16 has been dumped on stockpile 134) and prepare to withdraw from stockpile 134 to travel back to material pile 34 and collect more material. If controller 44 determines that trigger 74 of joystick 72 is pressed (step 530: Yes), controller 44 proceeds to step 640.

In step 640, controller 44 may determine if the extension of lift actuator 18 is greater than a third threshold value. The third threshold value may be any selected value of lift actuator extension that corresponds to the desired vertical position of bucket (or bucket height). In some embodiments, the third threshold value may be selected as the lift actuator extension that corresponds to between about 40-60% of the maximum bucket height. For example, if the maximum bucket height is H, in some embodiments, the third threshold value may be selected as the lift cylinder extension that results in a bucket height between about 0.4-0.6 H. It should be noted that this range of values is only exemplary, and in general, the third threshold value may be any predetermined (or preselected) value of lift actuator extension. If controller 44 determines that the lift actuator extension is not greater than the preselected third threshold value (step 640: No), controller 44 may proceed to (or instruct) withdraw machine 10 from material stockpile 134 (i.e., step 670). If controller 44 determines that the lift actuator extension is greater than the third threshold value (step 640: Yes), controller 44 proceeds to step 650.

In step 650, controller 44 determines if the extension of tilt actuator 20 is less than a fourth threshold value. In general, any value of tilt actuator extension that corresponds to the desired bucket tilt angle may be preselected as the fourth threshold value. In some embodiments, the fourth threshold value may be selected as the extension of the tilt actuator 20 that results in the lower surface 32 of bucket 16 being substantially horizontal. In some embodiments, when extension of lift actuator 18 is greater than the third threshold value and the extension of tilt actuator 20 is less than the fourth threshold value, bucket 16 may be in the dumping configuration illustrated in FIG. 2C. If controller 44 determines that the tilt actuator extension is not less than the fourth threshold value (step 650: No), controller 44 may proceed to (or instruct) withdraw machine 10 from stockpile 134 (i.e., step 670). If controller 44 determines that the tilt actuator extension is less than the fourth threshold value (step 650: Yes), controller 44 proceeds to step 660.

In step 660, controller 44 may execute a dumpout-shake routine on bucket 16. An exemplary dumpout-shake routine that may be executed by controller 44 will be described with reference to FIG. 8. In this step, controller 44 may shake bucket 16 to cause any loose or stuck material in bucket 16 to spill out onto stockpile 134. Controller 44 may shake bucket 16 by racking and unracking bucket 16 multiple times in quick succession. In one exemplary embodiment, controller 44 may rack and unrack bucket 16 at least 2 times in step 660. In general, in this step, controller 44 may rack and unrack bucket 16 about 2-10 times in rapid succession. In some embodiments, when the dumpout-shake routine is executed (in step 660), bucket 16 may rack and unrack in the same manner as when the settling shake routine is executed (e.g., in step 560). In some embodiments, there may be differences between the racking and unracking of bucket during dumpout-shake and settling-shake. As one example, during settling-shake, the bucket may first rack and then unrack, and during dumpout-shake, the bucket may first unrack and then rack (or vice versa). An exemplary dumpout-shake routine that may be performed in some embodiments will be discussed below with respect to FIG. 8.

In some embodiments, after executing the dumpout-shake routine (of step 660), controller 44 may return to step 630 to determine if trigger 74 is still pressed (i.e., step 630: Yes). If it is, controller 44 may continue to execute the dumpout-shake routine of step 660 if the conditions of steps 640 and 650 continue to be met. It the conditions of any of steps 630, 640, or 650 are no longer met, controller 44 may stop executing the dumpout-shake routine of step 660 and proceed to step 670.

In some embodiments, controller 44 may execute the dumpout-shake routine of step 660 for a predetermined amount of time and then proceed to step 670 without going back to check if trigger 74 is still pressed as shown in FIG. 6. For example, in step 630, controller 44 may determine if trigger 74 is kept pressed for the threshold value of time (e.g., any predetermined extent of time). And it is, and the conditions of both steps 640 and 650 are met, controller 44 may execute the dumpout-shake routine of step 660 for a predetermined amount of time and then proceed to step 670.

In step 670, controller 44 may cause machine 10 to withdraw from stockpile 134. After withdrawing from stockpile 134, machine 10 may proceed along a designated path back to the location of material pile 34 to collect more material. By shaking bucket 16 before withdrawing machine 10 from stockpile 134, method 600 may help ensure that loose or stuck material from bucket 16 does not dislodge and spill along the path from stockpile 134 to material pile 34. This in turn may help to keep the path clear of debris and reduce and/or eliminate the need to clean the path of any spillage from bucket 16 as machine 10 travels over the path. It should be noted that, in some embodiments the threshold values (e.g., first, second, third, and fourth threshold values) described with reference to methods 500 and 600 may be predetermined values programmed, for example, in controller 44. As explained with reference to FIG. 5, in embodiments where a bucket-shake routine (e.g., step 660) is activated at a different stage of the excavation process (e.g., while driving back to the material pile after dumping), steps 610, 620, and 670 may be eliminated.

FIG. 7 illustrates an exemplary method 700 for performing a settling-shake routine on bucket 16 in some embodiments of the current disclosure. In step 702, bucket 16 may be lifted above ground surface 28. In step 702, controller 44 may issue commands to cause lift actuators 18 to lift or raise bucket 16 above ground surface 28. In one exemplary embodiment, controller 44 may issue commands to hydraulic system 80 to operate pumps or other components to pump hydraulic fluid into lift actuators 18 causing lift actuators 18 to extend and raise bucket 16 above ground surface 28. In step 704, controller 44 determines whether a target extension (i.e. target length) has been reached by lift actuator 18. When controller 44 determines that lift actuator 18 has reached a target extension (step 704: Yes), controller 44 may proceed to step 708. The target extension may be predetermined or preselected value of extension. In some embodiments, the target extension may be preprogrammed into controller 44. When controller 44 determines, however, that lift actuator 18 has not reached the target extension (step 704: No), controller 44 may proceed to step 706 of determining whether lifting has timed out. In general, the target extension of lift actuator 18 may be any preselected (or predetermined) value. In one exemplary embodiment, the target extension may range from about 15% to 20% of a maximum length of extension of lift actuator 18.

In some embodiments, controller 44 may initialize a timer (i.e. set the timer to 0) when executing step 702 to lift bucket 16. Controller 44 may monitor an elapsed time as lift actuators 18 lift bucket 16 above ground surface 28. Controller may periodically compare the elapsed time with a target lift time, which may represent a maximum amount of time for lifting bucket 16 to the target height. Controller 44 may determine that lifting has timed out (step 706), when the elapsed time exceeds the target lift time and lift actuator 18 has not reached the target extension. When controller 44 determines that lifting has timed out (step 706: Yes), controller 44 may proceed to step 708. When controller 44 determines, however, that lifting has not timed out (step 706: No), controller 44 may return to step 702 to continue lifting bucket 16. Controller 44 may cycle through one or more of steps 702-706 to lift bucket 16 and help ensure that bucket 16 is out of material pile 34 before shaking bucket 16 to remove loose material from bucket 16. Steps 702-706 describe steps associated with loading material on bucket 16. In embodiments where the bucket-shake routine is executed at a different stage of the excavation process (e.g., during driving to the dump site after loading), steps 702-706 may be eliminated.

In step 708, controller 44 may perform a first rack of bucket 16. In step 708, controller 44 may issue commands to hydraulic system 80 to cause tilt actuators 20 to rack (i.e. tilt) bucket 16 away from ground surface 28. In one exemplary embodiment, in response to commands from controller 44, hydraulic system 80 may operate pumps or other components to pump hydraulic fluid into tilt actuators 20 causing it to extend and tilt bucket 16 away from ground surface 28. In step 710, controller 44 may determine if a tilt velocity V_tilt is less than a threshold tilt velocity of bucket 16. Controller 44 may use signals from, among other sensors, tilt sensor 58 to determine a tilt velocity of bucket 16 at periodic intervals as bucket 16 tilts away from ground surface 28. In some embodiments, controller 44 may determine the tilt velocity of bucket 16 based on the velocity (or rate of change of extension) of tilt actuator 20. When controller 44 determines that tilt velocity V_tilt of bucket 16 is less than a threshold velocity (step 710: Yes), controller 44 may proceed to step 714. When controller 44 determines, however, that tilt velocity V_tilt is greater than the threshold velocity (step 710: No), controller 44 may proceed to step 712 of determining whether first rack has timed out. Although not a requirement, in some embodiments, the threshold velocity may be selected to be about 0.03 m/s.

In some embodiments, controller 44 may initialize a timer (i.e. set the timer to 0) when executing step 708 of racking bucket 16. Controller 44 may monitor an elapsed time as tilt actuators 20 tilt bucket 16 away from ground surface 28. Controller may periodically compare the elapsed time with a target rack time, which may represent a maximum amount of time permitted for racking bucket 16. Controller 44 may determine that first rack has timed out (step 712), when the elapsed time exceeds the target first rack time and tilt velocity V_tilt of bucket 16 remains higher than the threshold velocity. When controller 44 determines that first rack has timed out (step 712: Yes), controller 44 may proceed to step 714. When controller 44 determines, however, that first rack has not timed out (step 712: No), controller 44 may return to step 708 to continue racking bucket 16. Controller 44 may cycle through one or more of steps 708-710 to rack bucket 16.

In step 714, controller 44 may perform a first unrack of bucket 16. In step 714, controller 44 may issue commands to hydraulic system 80 to cause tilt actuators 20 to unrack (i.e. tilt) bucket 16 towards ground surface 28. In one exemplary embodiment, in response to commands from controller 44, hydraulic system 80 may operate pumps or other components to pump hydraulic fluid out of tilt actuators 20 to cause tilt actuators 20 to contract and tilt bucket 16 towards ground surface 28. In step 716, controller 44 may determine whether a tip angle (β) of bucket 16 exceeds a target tip angle (β_Target). That is, if β>β_Target. In some embodiments, in step 716, controller 44 may determine if the tip angle is approximately equal to the target tip angle (i.e., if β≈β_Target). In general, the target tip angle may have any predetermined or preselected value. Although not a requirement, in some embodiments, β_Target may be selected to be between about 3°-5°. Controller 44 may use signals from, among other sensors, tilt sensor 58 to determine the tip angle of bucket 16 at periodic intervals as bucket 16 tilts towards ground surface 28. When controller 44 determines that tip angle exceeds the target tip angle (or tip angle is approximately equal to the target tip angle in some embodiments) (step 716: Yes), controller 44 may proceed to step 720. When controller 44 determines, however, that the tip angle is less than the target tip angle (step 716: No), controller 44 may proceed to step 718 of determining whether the first unrack has timed out.

In some embodiments, controller 44 may initialize a timer (i.e. set the timer to 0) when executing step 714 of unracking bucket 16. Controller 44 may monitor an elapsed time as tilt actuators 20 tilt bucket 16 toward ground surface 28. Controller 44 may periodically compare the elapsed time with a target unrack time, which may represent a maximum amount of time permitted for unracking bucket 16. Controller 44 may determine that first unrack has timed out when the elapsed time exceeds the target first unrack time and tip angle of bucket 16 remains higher than the target tip angle. When controller 44 determines that first unrack has timed out (step 718: Yes), controller 44 may proceed to step 720. When controller 44 determines, however, that first unrack has not timed out (step 718: No), controller 44 may return to step 714 to continue unracking bucket 16. Controller 44 may cycle through one or more of steps 714-718 to unrack bucket 16.

In step 720, controller 44 may perform a second rack of bucket 16 Controller 44 may perform processes similar to those described above for step 708 to perform the second rack of bucket 16. In step 722, controller 44 may determine if a tilt velocity V_tilt of bucket 16 is less than a threshold velocity of bucket 16. Controller 44 may perform processes similar to those described above for step 710 to determine whether the tilt velocity V_tilt is less than the threshold velocity of bucket 16. When controller 44 determines that the tilt velocity is less than the threshold velocity (step 722: Yes), controller 44 may end method 700. When controller 44 determines, however, that the tilt velocity of bucket 16 is greater than the threshold velocity (step 722: No), controller 44 may proceed to step 724 to determine if the second rack has timed out. Controller 44 may perform processes similar to those described above for step 712 to determine whether the second rack has timed out. When controller 44 determines that second rack has timed out (step 724: Yes), controller 44 may proceed to step 726. When controller 44 determines, however, that the second rack has not timed out (step 726: No), controller 44 may return to step 720 to continue racking bucket 16. Controller 44 may cycle through one or more of steps 720-724 to rack bucket 16.

Controller 44 may perform a second unrack of work-tool in step 726, determine whether the tip angle (β) exceeds the target tip angle (β_Target) in step 728, and determining whether the second rack has timed out in step 730. Controller 44 may perform processes similar to those described above for steps 714, 716, and 718 when performing steps 726, 728, and 730, respectively. In step 728, when controller 44 determines that the tip angle of bucket 16 exceeds the target tip angle (step 728: Yes), controller 44 may proceed to step 732. As explained with reference to step 716, in some embodiments, controller 44 may determine is the tip angle is approximately equal to the target tip angle in step 728 and proceed to step 732 if it is. When controller 44 determines, however, that the tip angle is less than the target tip angle (step 728: No), controller 44 may proceed to step 730 to determine whether the second unrack has timed out. In step 730, when controller 44 determines that the second unrack has timed out (step 730: Yes), controller 44 may proceed to step 732. When controller 44 determines, however, that second unrack has not timed out (step 730: No), controller 44 may return to step 726 to continue unracking bucket 16. Controller 44 may cycle through one or more of steps 726-728 to unrack bucket 16.

In step 732, controller 44 may perform a third rack of bucket 16. Controller 44 may perform processes similar to those described above for steps 708 or 720 to perform the third rack of bucket 16. In step 734, controller 44 may determine whether the third rack has timed out. Controller 44 may perform processes similar to those described above for steps 712 or 724 to determine whether the third rack has timed out. When controller 44 determines that the third rack has timed out (step 734: Yes), controller 44 may end method 700. When controller 44 determines, however, that the third rack has not timed out (step 726: No), controller 44 may return to step 732 to continue racking bucket 16. Controller 44 may cycle through one or more of steps 732-734 to rack bucket 16. It should be noted that although method 700 only illustrates three racks, any number (4, 6, 10, etc.) of rack and unrack cycles may be performed by controller 44. In some embodiments, the number of rack-unrack cycles performed during method 700 may be a preprogrammed value. In some embodiments, the rack-unrack cycles may continue until some predefined condition is met. For example, a second signal indicative of an operator command to stop the bucket-shake routine is received, the first signal that initiated the bucket-shake routine stops, when a sensor reading exceeds or is below a threshold value (or within a threshold range), etc.

Thus, to prevent loose material from falling off the bucket when the machine transports the material, the controller performs multiple successive racks and unracks of the bucket to shake material loose from the bucket when the operator initiates the shaking process after the loading. For example, controller 44 performs a first rack of bucket 16 (step 508), followed by a first unrack of bucket 16 (step 714), and a second rack of bucket 16 (step 520) to shake bucket 16 to allow loose material to spill from bucket 16 onto material pile 34. While performing second rack of bucket 16 (step 720), if controller 44 determines that the tilt velocity of bucket 16 is higher than the threshold velocity and if the third rack times out (i.e. the third rack cannot be completed in the allocated time), then controller 44 proceeds to perform a second unrack of bucket 16 (step 726), followed by a third rack of bucket 16 (step 732). The additional second unrack (step 726) and third rack (step 732) may allow controller 44 to help ensure bucket 16 is not stalled or stuck and can move freely before allowing machine 10 to withdraw from material pile 34. By performing the process of repeatedly racking and unracking bucket 16 according to method 700, controller 44 may help ensure that loose material from bucket 16 is dislodged at material pile 34, which may prevent debris from falling from bucket 16 onto the path travelled by machine 10 towards stockpile 134.

As described previously, controller 44 may perform a bucket-shake routine (e.g., the dumpout-shake routine) after discharging material from the bucket in a similar manner as it performs a bucket-shake routine after loading material into the bucket (e.g., the settling-shake routine). FIG. 8 illustrates an exemplary method 800 for performing a dumpout-shake routine on bucket 16 in some embodiments of the current disclosure. Since the steps of method 800 are similar to the steps of method 700, and these steps may be performed by controller 44 in a similar manner as described with reference to method 700, the steps of method 800 will not be described again. Instead the differences between the steps of methods 700 and 800 will be described. As described with reference to FIG. 7, steps 802-806 describe steps associated with unloading material from bucket 16. In embodiments where the bucket-shake routine is executed at a different stage of the excavation process (e.g., during driving back to the material pile after dumping), steps 802-806 may be eliminated. Similarly, as described with reference to FIG. 7, although only three racks are illustrated in FIG. 8, method 800 may include any number (4, 6, 10, etc.) of rack and unrack cycles performed by controller 44.

In some embodiments of method 800, controller 44 may perform an unrack of bucket 16 in steps 808, 820, and 832 and check if the unrack process has timed out in steps 812, 824, and 834. Similarly, in some embodiments of method 800, controller 44 may perform a rack of bucket 16 in steps 814 and 826 and check if the rack process has timed out in steps 818 and 830. Thus, to prevent loose or stuck material from falling off the bucket onto the path when the machine travels after dumping material from the bucket, the controller performs multiple successive unracks and racks of the bucket to shake material loose from the bucket when the operator initiates the shaking process after dumping. This may prevent debris from falling from the bucket onto the path travelled by the machine as it travels back to the material pile to collect more material.

It should be noted that the described embodiments are merely exemplary. In general, in embodiments of the current disclosure, a bucket-shake routine may be activated based on a signal indicative of an operator command to activate a bucket-shake routine. Upon receipt of this signal, if one or more other predefined conditions are met (e.g., signals received from one or more sensors of the machine meets predefined threshold conditions, etc.), a bucket-shake routine is activated. The bucket-shake routine may be activated at any stage during the operation of the machine. Although the threshold conditions are described as the lift cylinder and tilt cylinder extensions meeting predefined conditions, this is only exemplary. In general, the threshold conditions may be based on any sensor readings (e.g., distance sensor, speed sensor, load sensors, lift sensor, tilt sensor, lift pressure sensor, tilt pressure sensor, etc.) For example, in different embodiments, the threshold condition may be one or more of-the distance of the machine meeting a threshold value or being within a threshold range, the speed of the machine meeting a threshold value or being within a threshold range, the load on the bucket meeting a threshold value or being within a threshold range, etc.

In some embodiments, the disclosed apparatus and methods may include a controller that activates a bucket-shake routine based on a signal indicative of an operator command to activate a bucket-shake routine. Upon receipt of this signal, if one or more other predefined conditions are met (e.g., signals received from one or more sensors of the machine meets predefined threshold conditions, etc.), a bucket-shake routine may be activated. The bucket-shake routine may be activated at any stage during the operation of the machine. In some embodiments, a non-transitory computer readable medium may store a set of instructions, executable by at least on processor of a computing device, to cause the computing device to perform the above-described operations.

It will be apparent to those skilled in the art that various modifications and variations can be made to the disclosed excavation system. Other embodiments will be apparent to those skilled in the art from consideration of the specification and practice of the disclosed excavation system. It is intended that the specification and examples be considered as exemplary only, with a true scope being indicated by the following claims and their equivalents.