ASPHALT FINISHER AND CONSTRUCTION SUPPORT SYSTEM

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is based upon and claims priority to Japanese Patent Application No. 2024-226724, filed on Dec. 23, 2024, the entire contents of which are incorporated herein by reference.

BACKGROUND

1. Technical Field The present disclosure relates to an asphalt finisher and a construction support system.

2. Description of Related Art

Conventionally, an in-vehicle display device has been known that notifies an operator of an asphalt finisher upon an arrival of a transport vehicle that transports a paving material from an asphalt plant to a construction site being delayed.

An asphalt finisher can continue construction by repeatedly receiving a supply (replenishment) of paving material. from a plurality of. transport vehicles during construction (while traveling). However, if the arrival of a transport vehicle at the construction site is delayed due to traffic congestion or other conditions on the road from the asphalt plant to the construction site, the asphalt finisher may not be able to continue paving at its current travel speed. This is because, if the paving material is not supplied from the transport vehicle to the hopper, the amount of paving material becomes insufficient.

SUMMARY

According to one aspect of the present disclosure, an asphalt finisher includes:

• • a tractor;
  • a hopper installed on a front side of the tractor;
  • a conveyor configured to transport a paving material in the hopper to a rear side of the tractor;

screw configured to spread the paving material transported by the conveyor in a vehicle-width direction on a road surface;

• • a screed configured to level the paving material spread by the screw at a rear side of the screw; and
  • a computer including one or more processors and a memory storing executable instructions, which when executed by the one or more processors, cause the computer to perform a process including controlling traveling of the tractor based on a state of a transport vehicle that transports the paving material to be replenished to the hopper.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a left side view of an asphalt finisher and a dump truck according to an embodiment of the present disclosure.

FIG. 1B is a top view of the asphalt finisher and the dump truck according to the embodiment of the present disclosure.

FIG. 2 is a block diagram illustrating an example configuration of the asphalt finisher according to the embodiment of the present disclosure.

FIG. 3 is a flowchart illustrating an example flow of a first operation control process.

FIG. 4 is a flowchart illustrating an example flow of a second operation control process.

FIG. 5 is a flowchart illustrating another example flow of the first operation control process.

FIG. 6 is a flowchart illustrating yet another example flow of the first operation control process.

FIG. 7 is a flowchart illustrating yet another example flow of a third operation control process.

FIG. 8 is a schematic diagram illustrating an example configuration of a construction support system according to an embodiment of the present disclosure.

DETAILED DESCRIPTION

With respect to the above, the above-described in-vehicle display device is not configured to display information related to the traveling of the asphalt finisher when the supply of paving material from a transport vehicle to the hopper is delayed, for example, when the arrival of the transport vehicle at the construction site is delayed. Accordingly, the operator of the asphalt finisher may not be able to appropriately control the travel (movement) of the asphalt finisher when the supply of the paving material is delayed.

Accordingly, it is desirable to ensure that the asphalt finisher can appropriately advance even when the supply of the paving material is delayed.

The asphalt finisher described above can be operated such that the asphalt finisher appropriately advances even when the supply of the paving material is delayed.

Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. In each of the drawings, the same components corresponding components are denoted by the same reference numerals, and description thereof may be omitted.

FIGS. 1A and 1B illustrate an asphalt finisher 100 and a dump truck 200, which are examples of road machines according to an embodiment of the present disclosure.

Specifically, FIG. 1A is a left side view, and FIG. 1B is a plan view, More specifically, FIGS. 1A and 1B illustrate a state in which the dump truck 200 is approaching the asphalt finisher 100 while reversing.

The asphalt finisher 100 mainly includes a tractor 1, a hopper 2, and a screed device 3. The screed device 3 is a mechanism that levels the paving material. In this embodiment, the screed device 3 is a floating screed device towed by the tractor 1 and is connected to the tractor 1 via a leveling arm 3a. The hopper 2 is installed on the front side of the tractor 1 as a mechanism for receiving the paving material. The hopper 2 in this embodiment has a structure that can be opened and closed in the vehicle-width direction by a hopper cylinder 2a, with movable mechanism portions 81a and 81b serving as axes.

When the paving material in the hopper 2 is about to run out, the asphalt finisher 100 fully opens the hopper 2 to enable reception of the paving material from a dump bed 201 of a dump truck 200. The paving material is, for example, an asphalt mixture. The dump truck 200 supplies the paving material from the dump bed 201 to the hopper 2 while being in contact with the asphalt finisher 100.

Even while receiving the paving material from the dump bed 201 of the dump truck 200, the asphalt finisher 100 continues traveling (paving operation) while pushing the dump truck 200 forward. Specifically, a conveyor CV transports the paving material received in the hopper 2 to a rear side of the tractor 1. A screw SR spreads the paving material conveyed by the conveyor CV over the road surface in the vehicle-width direction. The screed device 3 levels the paving material spread by the screw SR at a rear side of the screw SR.

The asphalt finisher 100 can transport the paving material received in the hopper 2 to a rear side of the tractor 1 by means of the conveyor CV after receiving the paving material from the dump bed 201 of the dump truck 200. The operator of the asphalt finisher 100 can gather the paving material remaining in the hopper 2 onto the conveyor CV located at a central portion of the hopper 2 by closing the hopper 2 when the amount of the paving material in the hopper 2 falls below a predetermined level. The operator of the asphalt finisher 100 then opens the hopper 2 when the amount of the paving material in the hopper 2 further decreases, thereby setting the hopper 2 to a state ready to receive the paving material from the dump truck 200. The operator of the dump truck 200 typically backs the dump truck 200 toward and into contact with the hopper 2 after confirming that the hopper 2 is fully opened.

The asphalt finisher 100 includes a push roller 2b. The push roller 2b is installed in front of the hopper 2. The push roller 2b is configured to be contactable with rear wheels 202 of the dump truck 200, and to rotate together with the rear wheels 202 when the rear wheels 202 of the dump truck 200 are in contact with the push roller 2b.

The tractor 1 is a mechanism for driving the asphalt finisher 100. In the present embodiment, the tractor 1 includes front and rear wheels that are rotationally driven by travel hydraulic motors. The travel hydraulic motors rotate by receiving a supply of hydraulic oil from a hydraulic pump serving as a hydraulic source. The tractor 1 may be provided with crawlers instead of wheels.

The tractor 1 also includes a controller 30, a wireless communication device 40, a main monitor 60, a driver's seat 61, an imaging device 62, a sound output device 63, and the like. Specifically, a cab (driver's cabin) including the main monitor 60 and the driver's seat 61 is mounted on the upper surface of the tractor 1. The imaging device 62 and the sound output device 63 are mounted at the central front end of the upper surface of the tractor 1.

The wireless communication device 40 is an example of an information acquisition device configured to acquire information related to road construction, and is configured to communicate wirelessly with a device (external device) located outside the asphalt finisher 100. In the illustrated example, the wireless communication device 40 is configured to communicate wirelessly with an external device via an information Communication network such as a cellular communication network, a satellite communication network, or a short-range wireless communication network. The external device is, for example, a transport vehicle such as a dump truck 200, or an external facility such as an asphalt plant located remotely.

The main monitor 60 is a device configured to display various information to an operator of the asphalt finisher 100. In the illustrated example, the main monitor 60 is a liquid crystal display, and is configured to display various information in response to commands from the controller 30. The main monitor 60 also includes an input device 60a configured to receive operation inputs from the operator of the asphalt finisher 100.

The imaging device 62 is an example of a space recognition device and is configured to acquire an image of a space in front of the asphalt finisher 100. In the illustrated example, the imaging device 62 is a camera and is configured to output the acquired image to the controller 30. The imaging device 62 may be another space recognition device such as an RGBD camera, a LIDAR, a range image camera, an infrared camera, or a stereo camera.

The imaging device 62 also functions as another example of the information acquisition device, capturing an image of a space in an imaging area RAI, illustrated by the dash-dot line in FIG. 1A and B, which is present in front of the asphalt finisher 100. The imaging device 62 outputs the captured image to the controller 30. In the example illustrated in FIGS. 1A and 1B, the imaging device 62 can capture an image of a dump truck 200 located in the imaging area RA1. The imaging device 62 can also capture an image of the paving material in the hopper 2 within the imaging area RA1. The asphalt finisher 100 may also include an infrared sensor or an ultrasonic sensor configured to detect the height of the pile of paving material in the hopper 2, or the information acquisition device such as a load cell configured to detect the weight of the paving material in the hopper 2.

The sound output device 63 is a device configured to output sound toward the periphery of the asphalt finisher 100. In the illustrated example, the sound output device 63 is a speaker that outputs sound toward the front of the asphalt finisher 100, and can output sounds such as alarms in response to commands from the controller 30. The sound output device 63 may also output voice messages.

The controller 30 is a control device configured to control the asphalt finisher 100. The controller 30 is configured as a computer, and includes a CPU, internal memory, a nonvolatile storage device, and the like. The controller 30 performs various controls by causing the CPU to execute programs stored in the nonvolatile storage device.

FIG. 2 is a block diagram illustrating a configuration example of the asphalt finisher 100. In the illustrated example, the asphalt finisher 100 includes the imaging device 62, the input device 60a, the controller 30, and the wireless communication device 40. The controller 30 performs control based on image information or the like from the imaging device 62. The controller 30 performs various controls in accordance with operations input by the operator of the asphalt finisher 100 through the input device 60a.

The functional blocks of the controller 30 illustrated in FIG. 2 are conceptual and do not necessarily need to be physically configured as illustrated. All or part of the functional blocks may be functionally or physically distributed or integrated in any desired units. All or any part of the functional blocks may be implemented by a program executed by the CPU. Alternatively, the functional blocks may be implemented hardware using wired logic. Specifically, as illustrated in FIG. 2, the controller 30 includes, as functional blocks, a dump truck identification information storage 31, an acquisition part 32, an operation control part 33, a determination part 34, a generation part. 35, and a communication control part 36.

The dump truck identification information storage 31 is a functional block configured to store information used by the asphalt finisher 100 to identify a dump truck 200. In the illustrated example, the dump truck identification information storage 31 includes a nonvolatile storage device within the controller 30. For example, the dump truck identification information storage 31 stores license plate information of the dump truck 200. Accordingly, when the rear portion of the dump truck 200 is captured by the imaging device 62, the controller 30 can identify the dump truck 200 based on the captured license plate.

The acquisition part 32 is a functional block configured to acquire various information related to construction. In the illustrated example, the acquisition part 32 acquires image information related to an image captured by the imaging device 62. Further, the acquisition part 32 acquires operation information related to an operation by the operator of the asphalt finisher 100 via an input device 60a, which is another example of the information acquisition device. Further, the acquisition part 32 acquires information related to the operation of. the transport vehicle via a wireless communication device 40, which is also another example of the information acquisition device. The information related to the operation of the transport vehicle includes, for example, the current position of the dump truck 200, the time at which the dump truck departs from the asphalt plant, the scheduled arrival time at the construction site, weather information, traffic congestion information, and the like.

The operation control part 33 is a functional block configured to control the operation of the asphalt finisher 100. In the illustrated example, the operation control part 33 controls the operation of the asphalt finisher 100 by controlling the discharge rate of the hydraulic pump and by controlling the movement of a control valve for increasing or decreasing the flow rate of hydraulic oil supplied to each hydraulic actuator constituting the asphalt finisher 100.

The determination part 34 is a functional block configured to perform various determinations based on the information acquired by the acquisition part 32. In the illustrated example, the determination part 34 performs various determinations based on the image information from the imaging device 62. For example, the determination part 34 determines whether the amount of the paving material in the hopper 2 exceeds a preset amount based on the image captured by the imaging device 62. Further, the determination part 34 determines whether a dump truck 200 is present ahead of the asphalt finisher 100 based on the image information from the imaging device 62. Further, the determination part 34 determines whether the license plate information of a dump truck 200 captured in the image by the imaging device 62 is already registered. Any technique, including known image processing techniques, may be used for detecting a specific object or shape from an image. Further, the determination part 34 may be configured to detect various other objects. Such objects may include, for example, a road cone, a person (such as a worker), and a small machine (e.g., rammer, tamping machine, etc.). Further, the determination part 34 may be configured to determine the presence or absence of a specific object around the asphalt finisher 100 based on the image information (output value) from the imaging device 62 as the space recognition device. The objects to be determined may include, for example, a dump truck 200, topographical features (slope, hole, etc.), electric wires, utility poles, people, animals, vehicles, construction machines, buildings, walls, helmets, safety vests, work garments, or a predetermined mark on a helmet. As described above, the determination part 34 may be configured to determine the presence or absence of an object by identifying its shape. Further, the determination part 34 may be configured to distinguish a dump truck 200 from objects other than the dump truck 200.

The generation part 35 is a functional block configured to generate a control command for controlling the asphalt finisher 100. The generated control command may be, for example, a travel-stop command for stopping the progress of the asphalt finisher 100, an acceleration command for increasing the travel speed of the asphalt finisher 100, a deceleration command for reducing the travel speed of the asphalt finisher 100, or a start command for starting the stopped asphalt finisher 100. The control command generated by the generation part 35 is not limited to the above-described commands, and may be various other control commands. For example, the control command generated by the generation part 35 may be a command for turning the headlights on or off, or a command for outputting a warning to the operator of the asphalt finisher 100.

Further, the generation part 35 may be configured to generate a control command based on the determination result of the determination part 34. In this case, the control command may include, for example, a travel-stop command, an acceleration command, a deceleration command, or a start command.

The communication control part 36 is a functional block configured to control wireless communication between the asphalt finisher 100 and an external device. In the illustrated example, the communication control part 36 controls wireless communication between the asphalt finisher 100 and a dump truck 200 or the asphalt plant via the wireless communication device 40.

For example, when the determination part 34 determines that a dump truck 200 does not arrive at the construction site in time, the generation part 35 may generate a travel-stop command for stopping the progress of the asphalt finisher 100. When the determination part 34 determines that a dump truck 200 will arrive late at the construction site, the generation part 35 may generate a deceleration command for reducing the travel speed of the asphalt finisher 100. When the delay in the arrival of a dump truck 200 is resolved after the travel speed of the asphalt finisher 100 is reduced, the generation part 35 may generate an acceleration command for increasing the travel speed of the asphalt finisher 100. This is for returning the travel speed of the asphalt finisher 100 to the original travel speed (the travel speed before the automatic deceleration is started).

Specifically, based on the information acquired by the acquisition part 32, when the determination part 34 determines that a dump truck 200 cannot arrive in time even if the asphalt finisher 100 is driven at a predetermined minimum allowable travel speed, it determines that a dump truck 200 is not expected to arrive in time. Incidentally, this means, for example, that the paving material in the hopper 2 cannot be replenished from the dump truck 200 before it falls below a predetermined allowable minimum amount. Further, when the determination part 34 determines that a dump truck 200 cannot arrive in time while the asphalt Finisher 100 continues at the current set travel speed, but can arrive in time when the asphalt finisher is driven at the minimum allowable travel speed, it determines that a dump truck 200 is expected to be delayed. Further, when the determination part 34 determines that a dump truck 200 can arrive in time even if the stopped asphalt finisher 100 is started and driven at the initial set travel speed, it determines that the delay of the dump truck 200 has been resolved. The information acquired by the acquisition part 32 may include, for example, the departure time of the dump truck 200 from the asphalt plant.

When the determination part 34 determines that a dump truck 200 cannot arrive in time, the generation part 35 generates a travel-stop command and outputs it to the operation control part 33 when the remaining amount of the paving material in the hopper 2 is below a predetermined amount. Further, when the determination part 34 determines that a dump truck 200 is expected to be delayed, the generation part 35 generates a deceleration command and outputs it to the operation control part 33. When the determination part 34 determines that the delay of the dump truck 200 has been resolved, the generation part 35 generates a start command or an acceleration command and outputs the generated command to the operation control part 33.

Upon receiving the travel-stop command, the operation control part 33 stops the traveling of the asphalt finisher 100 (tractor 1) by closing a travel control valve provided on a hydraulic oil line connecting the hydraulic pump and the travel hydraulic motor, thereby stopping the travel hydraulic motor. Upon receiving the acceleration command, the operation control part 33 accelerates the asphalt finisher 100 by adjusting the movement of the travel control valve to increase the rotational speed of the travel hydraulic motor. Upon receiving the deceleration command, the operation control part 33 decelerates the asphalt Finisher 100 by adjusting the movement of the travel control valve to decrease the rotational speed of the travel hydraulic motor. In this case, the operation control part 33 may gradually reduce the travel speed of the asphalt finisher to the minimum allowable travel speed in predetermined steps. This is because a sudden or continuous gradual reduction in travel speed may adversely affect the finishing quality of the pavement surface. However, the operation control part 33 may reduce the travel speed either suddenly or gradually as necessary. The same applies when accelerating the asphalt finisher 100. Further, upon receiving the start command, the operation control part 33 opens the travel control valve to resume rotation of the travel hydraulic motor, thereby resuming traveling of the stopped asphalt finisher. The operation control part 33 may also stop rotation of the conveyor CV and screw SR when the tractor i stops, and may decelerate rotation of the conveyor CV and screw SR when the tractor 1 decelerates. The operation control part 33 may resume rotation of the conveyor CV and screw SR when the tractor 1 resumes traveling.

Next, referring to FIG. 3, an example of a process (hereinafter referred to as “first operation control process”) for controlling the movement f the asphalt finisher 100 while it is traveling will be described. FIG. 3 is a flowchart illustrating an example of the flow of the first operation control process. While the asphalt finisher 100 is traveling, the controller 30 repeatedly executes this first operation control process at predetermined control intervals.

First, the controller 30 determines whether the amount of paving material in the hopper 2 is less than a predetermined amount (step ST1). In the illustrated example, the controller 30 determines whether the amount of paving material in the hopper 2 is less than the preset predetermined amount based on an image (in-hopper image) captured by the imaging device 62, which is information acquired by the acquisition part 32. The controller 30 may calculate (or estimate) the amount of paving material in the hopper 2 based on the in-hopper image, and determine whether the calculated (or estimated) amount is less than the predetermined amount. Further, the controller 30 may determine whether the amount of paving material in the hopper 2 is less than the predetermined amount based on the output of the information acquisition device such as a LiDAR sensor, an infrared sensor, or an ultrasonic sensor for detecting the height of a pile of the paving material in the hopper 2, or a load cell for detecting the weight of the paving material in the hopper 2.

The predetermined amount may be a variable value that is determined based on the travel speed of the asphalt finisher 100, the current position of a dump truck 200, or similar factors, or a fixed value that is set independently of the travel speed of the asphalt finisher 100 and the current position of the dump truck 200. Further, the predetermined amount may be a variable value that varies according to at least one of the paving thickness or the paving width.

When it is determined that the amount of paving material in the hopper 2 is equal to or greater than the predetermined amount (NO in step ST1), the controller 30 ends the present first operation control process without stopping the traveling of the asphalt finisher 100 (tractor 1). This is because it is considered premature to determine whether the traveling of the tractor 1 should be stopped.

On the other hand, when it is determined that the amount of paving material in the hopper 2 is less than the predetermined amount (YES in step ST1), the controller 30 determines whether a dump truck 200 on standby is present (step ST2). In the illustrated example, the controller 30 determines whether a dump truck 200 is present in front of the asphalt finisher 100 based on an image (front image) captured by the imaging device 62. When it is determined that a dump truck 200 is located within a predetermined distance range from the asphalt finisher 100, the controller 30 determines that a dump truck 200 on standby is present. Specifically, when it is determined that a dump truck 200 is present in front of the asphalt finisher 100, the controller 30 calculates the distance between the asphalt finisher 100 and the dump truck 200, and determines that a dump truck 200 on standby is present when the calculated distance is equal to or less than the predetermined distance.

The controller 30 assigns a “replenished” label to a dump truck 200 that has already completed the replenishment of the paving material into the hopper 2. This is because the dump truck can be distinguished from a dump truck 200 on standby and has not yet completed the replenishment of the paving material into the hopper 2. The assignment of the “replenished” label is implemented, for example, by changing the value of a replenished flag set in the dump truck identification information storage 31 from “0 (zero)” to “1”. For example, the controller 30 may be configured to assign a replenished label to the dump truck 200 (which has not yet been assigned the replenished label) when the dump truck 200, located within a predetermined standby area set around the asphalt finisher 100, leaves the standby area.

On the other hand, when it is determined that a dump truck 200 is not present within a predetermined distance range from the asphalt finisher 100, the controller 30 determines that a dump truck 200 on standby is not present. It is noted that the standby area is not required to be included in the predetermined distance range. In this case, the controller 30 determines that a dump truck 200 is not present within the predetermined distance range even when a dump truck 200 is located within the standby area that lies within the predetermined distance range from the asphalt finisher 100. Further, even when the controller 30 determines that a dump truck 200 is present within the predetermined distance range from the asphalt finisher 100, the controller 30 determines that a dump truck 200 on standby is not present when the dump truck 200 has been assigned the replenished label.

When it is determined that a dump truck 200 on standby is present (YES in step ST2), the controller 30 ends the first operation control process without stopping the traveling of the asphalt finisher 100 (tractor 1). This is because it is unnecessary to stop the traveling of the tractor 1 when the supply of paving material can be received immediately.

On the other hand, when it is determined that a dump truck 200 on standby is not present (NO in step ST2), the controller 30 stops the traveling of the asphalt finisher 100 (step ST3). If construction is continued without stopping the asphalt finisher 100, almost all of the paving material in the hopper 2 would be used before receiving a supply from a dump truck 200. That is, the hopper 2 would become empty before receiving the supply. In other words, when the supply of paving material cannot be immediately received from a dump truck 200 due to its absence, the controller 30 stops the traveling of the asphalt finisher 100, thereby preventing the amount of paving material in the hopper 2 from falling below a predetermined amount. Further, while the asphalt finisher 100 is stopped and waiting for the next dump truck 200 to arrive, the controller 30 can maintain the amount of paving material in the hopper 2 at or above a predetermined amount. Therefore, the controller 30 can suppress rapid cooling of the paving material remaining in the hopper 2. This is because the larger the amount remaining in the hopper 2, the greater its heat capacity and the slower it cools. As a result, the controller 30 can prevent the temperature of the paving material in the hopper 2 from dropping to a level unsuitable for construction, even when the amount remaining in the hopper 2 falls below the predetermined amount while a dump truck 200 is in the standby state (with traveling being stopped).

When the asphalt finisher 100 is stopped, the controller 30 makes the hopper 2 in a fully closed state. This prevents relatively low-temperature ambient air around the hopper 2 from contacting the paving material and cooling it, thereby maintaining the heat of the paving material in the hopper 2.

In the first operation control process described above, the controller 30 is configured to automatically stop the traveling of the asphalt finisher 100 when a predetermined condition is satisfied. However, the controller 30 may instead be configured to prompt the operator of the asphalt finisher 100 to stop the traveling of the asphalt finisher 100, rather than automatically stopping the traveling Of the asphalt finisher 100. Specifically, the controller 30 may display a text message prompting the operator to stop the traveling of the asphalt finisher 100 on the main monitor 60, or output a voice message prompting the stop of the traveling of the asphalt finisher 100 from the sound output device 63. Further, the information for prompting the stop of the traveling of the asphalt finisher 100 may be displayed on another monitor (different from the main monitor 60) mounted on the asphalt finisher 100, or on a display device such as a tablet PC carried by a site supervisor or another related person.

Further, the controller 30 may be configured to adjust the stopping position of the asphalt finisher 100 when stopping its travel. For example, when it is determined, based on a front image, that a supply obstacle is present within a predetermined range in front of the asphalt finisher 100, the controller 30 may delay or advance the timing to stop the traveling of the asphalt finisher 100. The “supply obstacle” refers to an obstacle that may come into contact with the dump bed 201 when a dump truck 200 dumps the dump bed 201 upward, and includes, for example, a traffic signal or a street tree. More specifically, the controller 30 may stop the asphalt finisher 100 at a position where the dump bed 201 of the dump truck 200, docked with the front portion of the stopped asphalt finisher 100, does not come into contact with a traffic signal or the like when the dump bed 201 is raised to supply the paving material into the hopper 2.

Next, an example of a process (hereinafter referred to as “second operation control process”) in which the controller 30 controls the movement of the asphalt finisher 100 while the asphalt finisher 100 is stopped will be described with reference to FIG. 4. FIG. 4 is a flowchart illustrating the second operation control process. While the asphalt finisher 100 is stopped, the controller 30 repeatedly executes the second operation control process at predetermined intervals.

First, the controller 30 determines whether the amount of the paving material in the hopper 2 is greater than a predetermined amount (step ST11). In the illustrated example, the controller 30 determines whether the amount of the paving material in the hopper 2 is greater than the predetermined amount based on an image captured in the hopper 2. When the asphalt finisher 100 is stopped, the amount of the paving material in the hopper 2 typically increases when the paving material is supplied from a dump truck 200.

The controller 30 may be configured to remotely operate a dump truck 200, either automatically or manually, by using short-range wireless communication or the like when the paving material is supplied from the dump truck 200. This configuration allows the dump truck 200 to be guided and properly docked with the asphalt finisher 100.

For example, when the controller 30 determines that a dump truck 200 is present in front of the asphalt finisher 100 based on the front image, the hopper 2 is fully opened. Then, the controller 30 automatically and remotely steers the dump truck 200 and moves it forward or rearward so that the longitudinal axis (front-rear axis) of the asphalt finisher 100 is aligned with the longitudinal axis (front-rear axis) of the dump truck 200. Then, the controller 30 moves the dump truck 200 rearward while the longitudinal axis of the asphalt finisher 100 is aligned with the longitudinal axis of the dump truck 200, and docks the dump truck 200 to the asphalt finisher 100. That is, the controller 30 brings the rear wheels of the dump truck 200 into contact with the push roller 2b of the asphalt finisher 100.

When it is determined that the amount of the paving material in the hopper 2 is equal to or less than a predetermined amount (NO in step ST11), the controller 30 ends the second operation control process without starting or resuming the traveling of the asphalt finisher 100 (tractor 1). This is because the traveling of the tractor 1 cannot be resumed due to the insufficient amount of the paving material in the hopper 2.

On the other hand, when it is determined that the amount of the paving material in the hopper 2 is greater than a predetermined amount (YES in step ST11), the controller 30 starts or resumes the traveling of the asphalt finisher 100 (step ST12). In the illustrated example, after the supply of the paving material from a dump truck 200 to the hopper 2 has started, the controller 30 resumes the traveling of the asphalt finisher 100 when the rear wheels of the dump truck 200 are still in contact with the push roller 2b. Therefore, the asphalt finisher 100 moves forward while pushing the dump truck 200 forward.

When the asphalt finisher 100 automatically starts traveling, the controller 30 may output a warning sound from the sound output device 63. This is to inform relevant personnel, such as an operator of the asphalt finisher 100, workers working around the asphalt finisher 100, or a driver of the dump truck 200, in advance that the asphalt finisher 100 starts traveling.

In the second operation control process described above, the controller 30 is configured to automatically start (resume) traveling of the asphalt finisher 100 when predetermined condition is satisfied. However, the controller 30 may be configured not to automatically resume traveling of the asphalt finisher 100 but to prompt the operator of the asphalt finisher 100 to resume traveling of the asphalt finisher 100. Specifically, the controller 30 may cause the main monitor 60 to display a text message prompting resumption of traveling of the asphalt finisher 100, or may cause the sound output device 63 to output a voice message prompting resumption of traveling of the asphalt finisher 100. Further, information for prompting resumption of traveling of the asphalt finisher 100 may be displayed on another display device (another monitor different from the main monitor 60) mounted on the asphalt finisher 100, or may be displayed on a display device such as a tablet PC carried by relevant personnel such as a site supervisor.

Next, another example of the first operation control process will be described with reference to FIG. 5. FIG. 5 is a flowchart illustrating another example of the first operation control process. While the asphalt finisher 100 is traveling, the controller 30 repeatedly executes the first operation control process at a predetermined control cycle.

The first operation control process illustrated in FIG. 5 differs from the first operation control process shown in FIG. 3 in that step ST22 is executed instead of step ST2, but is otherwise the same as the first operation control process illustrated in FIG. 3. Therefore, in the following description, explanations of common portions are omitted, and differences will be described in detail.

Specifically, when it is determined that the amount of paving material in the hopper 2 is less than a predetermined amount (YES in step ST21), the controller 30 determines whether a dump truck 200 will fail to arrive in time (step ST22). In the illustrated example, the controller 30 determines whether a dump truck 200 will fail to arrive in time based on information acquired by the acquisition part 32, which is information input by the operator of the asphalt finisher 100 through an input device 60a. In this case, for example, when the operator of the asphalt finisher 100 receives, on a portable terminal device (e.g., a smartphone) carried by the operator, a notification from an external source that a dump truck 200 will not arrive in time, the operator inputs information for notifying the controller 30 of that fact through the input device 60a. The controller 30 determines that a dump truck 200 will not arrive in time based on the information input through the input device 60a. The term “external source” refers, for example, to a manager located in an external facility such as an asphalt plant or a management center, or a driver of the dump truck 200. The “external source” may also be a communication device installed in the asphalt plant, the management center, or a dump truck 200. That is, information indicating that a dump truck 200 will not arrive in time may be automatically transmitted by such a communication device or the like.

The controller 30 may determine that the arrival of a dump truck 200 will be delayed based on information acquired by the acquisition part 32 through the wireless communication device 40. In this case, the information acquired by the acquisition part 32 through the wireless communication device 40 includes, for example, position information output from a positioning device such as a GNSS receiver mounted on a dump truck 200, traffic congestion information transmitted by an external organization such as a road traffic information center, or weather information transmitted by an external organization such as the Japan Meteorological Agency. The controller 30 may also determine whether a dump truck 200 on standby is present in front of the asphalt finisher 100 based on an image (front image) captured by the imaging device 62, and determine whether the arrival of a dump truck 200 will be delayed based on the determination result.

When it is determined that the arrival of a dump truck 200 will be delayed (YES in step ST2), the controller 30 stops the traveling of the asphalt finisher 100 (step ST23).

In this manner, the controller 30 may determine whether to stop the traveling of the asphalt finisher 100 by determining whether the arrival of a dump truck 200 will be delayed, instead of determining whether a dump truck 200 on standby is present.

Next, another example of the first operation control process will be described with reference to FIG. 6. FIG. 6 is a flowchart illustrating another example of the flow of the first operation control process. The controller 30 repeatedly executes the first operation control process at predetermined control intervals while the asphalt finisher 100 is traveling.

The first operation control process illustrated in FIG. 6 differs from the first operation control process illustrated in FIG. 5 in that steps ST32 and ST33 are executed in place of steps ST22 and ST23, but is the same as the first operation control process illustrated in FIG. 5 in other respects. Therefore, the description of the common portions will be omitted, and only the differences will be described in detail below.

Specifically, when it is determined that the amount of paving material in the hopper 2 is less than a predetermined amount (YES in step ST31), the controller 30 determines whether the arrival of a dump truck 200 is delayed (step ST32). In the illustrated example, the controller 30 determines whether the arrival of a dump truck 200 is delayed based on information acquired by the acquisition part 32 (information input by the operator of the asphalt finisher 100 through the input device 60a).

When it is determined that the arrival of a dump truck 200 is delayed (YES in step ST32), the controller 30 causes the asphalt finisher 100 to decelerate (step ST33). In this case, the controller 30 may determine a deceleration mode (i.e., how to decelerate the asphalt finisher 100) in accordance with the current set pavement width, set pavement thickness, or the like, in order to suppress an effect on the pavement thickness. Further, the controller 30 may be configured to notify relevant personnel in advance that the asphalt finisher 100 will be decelerated, or to notify them afterwards that the asphalt finisher 100 has been decelerated, thereby prompting them to confirm the pavement quality such as the pavement thickness. The notification to the relevant personnel may be visually provided using the main monitor 60 or the like, or audibly provided using the sound output device 63 or the like.

In this manner, the controller 30 may determine whether the arrival of a dump truck 200 is delayed, instead of determining whether a dump truck 200 on standby is present or whether a dump truck 200 will not arrive in time. When it is determined that the arrival of a dump truck 200 is delayed, the controller 30 may decelerate the asphalt finisher 100 instead of stopping its travel. In this case, the asphalt finisher 100 can continue the paving operation without interruption and can receive a supply of the paving material from a dump truck 200, which has arrived at the construction site late, before the paving material in the hopper 2 is used up.

Next, referring to FIG. 7, an example of a process (hereinafter referred to as “third operation control process”) in which the controller 30 controls the movement of the asphalt finisher 100 during automatic deceleration will be described. FIG. 7 is a flowchart illustrating an example of the flow of the third operation control process. While the asphalt finisher 100 is automatically decelerating, the controller 30 repeatedly executes the third operation control process at predetermined control intervals.

First, the controller 30 determines whether or not to accelerate the asphalt finisher 100 (step ST41). In the illustrated example, the controller 30 determines whether or not to accelerate the tractor 1 based on information acquired by the acquisition part 32 (information input by the operator of the asphalt finisher 100 through the input device 60a). For example, the operator of the asphalt finisher 100 can learn via communication that a traffic jam or other factor causing a delay in the arrival of a dump truck 200 has changed, and that a dump truck 200 predicted to be delayed is now expected to arrive earlier. The operator can then determine that a dump truck 200 will arrive in time even if the tractor 1 travels at the speed before automatic deceleration begins. In this case, the operator can input information to the controller 30 indicating that the asphalt finisher 100 may be accelerated. Upon receiving this information, the controller 30 determines that the asphalt finisher 100 may be accelerated. It should be noted that the controller 30 may acquire various information, such as the position of a dump truck 200 or traffic conditions, through communication, and determine whether the asphalt finisher 100 may be accelerated.

When it is determined that the asphalt finisher 100 may be accelerated (YES in step ST41), the controller 30 causes the asphalt finisher 100 to accelerate (step ST42). In this case, the controller 30 may decide an acceleration mode (i.e., how to accelerate the asphalt finisher 100) according to the current set pavement width, set pavement thickness, or the like, in order to suppress an effect on the pavement thickness. Further, the controller 30 may be configured to inform the relevant persons beforehand that the asphalt finisher 100 will be accelerated, or may be configured to inform the relevant persons afterwards that the asphalt finisher 100 has been accelerated. This is to prompt the relevant persons to confirm the pavement quality, such as the pavement thickness. The notification to the relevant persons may be visually provided using the main monitor 60 or the like, or audibly provided using the sound output device 63 or the like.

In this manner, for example, when the controller 30 determines that the delay in the arrival of a dump truck 200 has been resolved, the asphalt finisher 100 that has been decelerated may be accelerated to return its travel speed to the original speed. Alternatively, the controller 30 may accelerate the asphalt finisher 100 to a travel speed higher than the original speed.

In addition, regardless of which of the above-described first, second, or third operation control processes is being executed, the controller 30 may be configured to display related information on the main monitor 60 or the like. The related information may be, for example, an image representing a positional relationship between the asphalt finisher 100 and a dump truck 200, or an image representing whether or not a dump truck 200 on standby is present. Further, the related information may be an image representing whether or not a dump truck 200 located in front of the asphalt finisher 100 has already supplied paving material to the hopper 2.

Next, with reference to FIG. 8, a construction support system SYS according to an embodiment of the present disclosure will be described. FIG. 8 is a schematic diagram illustrating a configuration example of the construction support system SYS, which supports construction by the asphalt Finisher 100 by automatically performing control related to traveling of the asphalt finisher 100.

The construction support system SYS is a system that supports construction by the asphalt finisher 100. In the illustrated example, the construction support system SYS mainly includes the asphalt finisher 100, a dump truck 200, a management device 300, and an asphalt plant 400. Each of the asphalt finisher 100, the dump truck 200, the management device 300, and the asphalt plant 400 is provided with a wireless communication device and may be directly or indirectly connected via an information communication network IN such as a cellular phone network, a satellite communication network, or a short-range wireless network. The number of each of the asphalt finisher 100, the dump truck 200, the management device 300, and the asphalt plant 400 constituting the construction support system SYS may be one or more. In the illustrated example, the construction support system SYS includes two asphalt finishers 100 (a first asphalt finisher 100A and a second asphalt finisher 100B), three dump trucks 200 (a first dump truck 200A, a second dump truck 200B, and a third dump truck 200C), one management device 300, and two asphalt plants 400 (a first asphalt plant 400A and a second asphalt plant 400B). The construction support system SYS may be configured without including a dump truck 200 and/or the asphalt plant 400.

The management device 300 is a device for managing construction by the asphalt finisher 100. In the illustrated example, the management device 300 is server computer installed in a management center or the like located away from the execution site, and includes a server-side controller 50, a display device 51, an input device 52, and a wireless communication device 53. The management device 300 may be a portable computer (for example, a laptop PC, a tablet PC, or a smartphone). In the illustrated example, the management device 300 is a desktop PC, the display device 51 is a liquid crystal display, and the input device 52 is a keyboard and a mouse.

The server-side controller 50 is configured to control the management device 300. In the illustrated example, the server-side controller 50 is configured as a computer including a CPU, a RAM, a ROM, and a nonvolatile storage device. Then, the server-side controller 50 reads a program corresponding to each functional element from the ROM into the RAM and causes the CPU to execute the corresponding process. However, each functional element may be configured by hardware or a combination of software and hardware.

Specifically, the server-side controller 50 is configured to execute the first operation control process, the second operation control process, and the third operation control process in the same manner as the controller 30. That is, the server-side controller 50 is configured to stop, decelerate, or resume traveling of the first asphalt finisher 100A and the second asphalt finisher 100B, respectively, when a predetermined condition is satisfied. The predetermined condition is satisfied, for example, when a dump truck 200 on standby is not present, when a dump truck 200 will not arrive in time, or when a dump truck 200 is delayed, as described above.

With this configuration, the server-side controller 50 can stop, accelerate, decelerate, ox resume traveling of the asphalt finisher 100 via remote control in the same manner as the controller 30.

As described above, the asphalt finisher 100 according to the embodiment of the present disclosure includes a tractor 1, a hopper 2 installed on the front side of the tractor 1, a conveyor CV configured to transport a paving material in the hopper 2 to a rear side of the tractor 1, a screw SR configured to spread the paving material conveyed by the conveyor CV in the vehicle-width direction on a road surface, a screed device 3 as a screed configured to level the paving material spread by the screw SR at a rear side of the screw SR, and a controller 30 as a control device configured to control traveling of the tractor 1 based on a condition of a dump truck 200 as a transport vehicle that transports paving material to be supplied into the hopper 2.

With this configuration, the controller 30 can appropriately control the traveling of the asphalt finisher 100 even when the replenishment of the paving material is delayed. This is because the controller 30 can stop, decelerate, or resume the traveling of the asphalt finisher 100 based on the amount of the paving material remaining in the hopper 2, the condition of a dump truck 200, or the like. Therefore, this configuration can reduce the workload of the operator of the asphalt finisher 100 or the workers working around the asphalt finisher 100, thereby reducing the number of required personnel.

In other words, the relevant personnel are relieved from the stressful work such as continuously monitoring the remaining amount of the paving material in the hopper 2 and the standby state and delay state of a dump truck 200 to determine whether it is necessary to temporarily suspend the construction. Therefore, this configuration can suppress improper suspension of the construction due to inappropriate determinations by the relevant personnel.

Further, this configuration can achieve further manpower saving and labor saving in the construction by the asphalt finisher 100 by combining, for example, the automation of stopping, decelerating, or resuming the traveling of the asphalt finisher 100 in accordance with the site conditions with the automation of other operations such as steering operation, screed expansion/contraction operation, or pavement thickness adjustment operation. This is because even if the automation of other operations is realized, the state in which the number of relevant personnel cannot be reduced cannot be overcome unless the automation of stopping, decelerating, or resuming the traveling of the asphalt finisher 100 in accordance with the site state is realized. Accordingly, this configuration provides an effect of solving problems such as the aging of relevant personnel and a shortage of manpower by achieving further manpower and labor saving.

Further, the controller 30 may be configured to control the traveling of the tractor 1 based on the standby state or the operating state of a dump truck 200. The standby state of a dump truck 200 includes, for example, a state indicating whether or not a dump truck 200 for supplying the paving material is already present on standby in front of the asphalt finisher 100. The operating state of a dump truck 200 includes, for example, a state indicating whether or not the dump truck 200 traveling from the asphalt plant to the construction site arrives at the construction site before the asphalt finisher 100 uses up the paving material in the hopper 2.

This configuration provides an advantageous effect that it becomes possible to more appropriately determine whether to stop the traveling of the asphalt finisher 100 in accordance with the site state. Therefore, this configuration provides an advantageous effect of suppressing inappropriate control execution regarding the traveling of the asphalt finisher 100 based on a state of a dump truck 200. Specifically, this configuration can suppress the occurrence of a state in which the construction by the asphalt finisher 100 is delayed because the traveling of the asphalt finisher 100 is interrupted midway, even though a dump truck 200 arrives as scheduled. Alternatively, this configuration can suppress the occurrence of a state in which the asphalt finisher 100 is kept stopped for a long period of time with almost no paving material remaining in the hopper 2 because the arrival of a dump truck 200 is delayed.

Further, the controller 30 may be configured to stop the traveling of the tractor 1 or to reduce the travel speed of the tractor 1 when the amount of paving material in the hopper 2 falls below a predetermined amount and a dump truck 200 on standby is not present.

This configuration provides an advantageous effect in that the traveling of the tractor 1 can be controlled at a more appropriate timing. Specifically, this configuration can suppress the occurrence of a state in which the traveling of the tractor 1 is stopped unnecessarily early even though a large amount of paving material remains in the hopper 2. Furthermore, this configuration provides an advantage in that, for example, instead of stopping the traveling of the tractor 1, the travel speed of the tractor 1 is automatically adjusted to a lower speed, thereby improving the finish quality of the pavement surface as compared with the case where the traveling of the tractor 1 is stopped.

Further, after the travel speed of the tractor 1 has been decreased, the controller 30 may increase the travel speed of the tractor 1 to return to its original travel speed. This configuration can automatically return the travel speed of the tractor 1 to its original speed even after the travel speed of the tractor 1 is decreased, for example, when a change occurs in the standby state or delay state of a dump truck 200 and the supply of the paving material can be received early. Therefore, this configuration provides an effect that the burden on the relevant personnel can be further reduced as compared with the case where the travel speed of the tractor 1 is manually returned.

Further, the controller 30 may be configured to start the traveling operation of the tractor 1 when the amount of paving material in the hopper 2 becomes equal to or greater than a predetermined amount.

This configuration not only automatically stops the traveling of the tractor 1 but also automatically resumes the traveling of the tractor 1, thereby further reducing the burden on relevant personnel.

Further, the construction support system SYS according to the embodiment of the present disclosure includes a server-side controller 50 as a control device configured to control traveling of the tractor 1 based on a state of a dump truck 200 that transports paving material supplied to the hopper 2.

This configuration provides an effect that the burden on the relevant personnel at each of a plurality of construction sites can be reduced without mounting, on each of the plurality of asphalt finishers 100, a control device configured to execute special processing such as the first operation control process, the second operation control process, and the third operation control process. This is because the server-side controller 50 can remotely control traveling of each of the plurality of asphalt finishers 100.

Further, in the embodiment described above, although the imaging device 62 is attached to the asphalt finisher 100, the imaging device 62 may be attached to an aerial vehicle such as a multicopter flying over the construction site, or the imaging device 62 may be attached to a structure such as a steel tower installed at the construction site.

The preferred embodiments of the present invention have been described in detail. However, the present invention is not limited to the embodiments described above, nor is it limited to the embodiments described below. Various modifications, substitutions, and the like may be made to the embodiments described above or below without departing from the scope of the present invention. Further, the features described separately may be combined as long as no technical inconsistency arises.