Patent Application
20230203783
The present invention relates to a work machine, a method and a system for controlling a work machine.
Conventionally, a technique for automatically controlling travel of a work machine such as a bulldozer is known. For example, in order to realize the travel along a desired straight line path, Patent Document 1 discloses a technique for controlling a work implement to return to a straight line path when it has deviated from the straight line path.
Patent Document 1: Japanese Unexamined Patent Publication 2012-36726
In digging work in which a work vehicle repeatedly travels back and forth on a work path called a slot to remove a surface soil, a plurality of work vehicles perform digging work on different slots individually. Therefore, it is preferable to prevent a work machine from deviating from the work path. An object of the present disclosure is to prevent a work machine traveling under automatic control from deviating from a work path.
A method according to a first aspect of the present disclosure is a method for controlling a first work machine including a work implement. The method according to the present aspect includes the following processes. A first process is to acquire a traveling state of the first work machine that is performing work with the work implement while traveling on a first work path. A second process is to determine whether the first work machine is deviating from the first work path based on the traveling state. A third process is to stop travel of the first work machine upon determining that the first work machine is deviating from the first work path.
A system according to a second aspect of the present disclosure is a system for controlling a first work machine including a work implement. The system according to the present aspect includes a communication device that communicates with the first work machine, and a remote controller. The remote controller acquires a traveling state of the first work machine that is performing work with the work implement while traveling on a first work path. The remote controller determines whether the first work machine is deviating from the first work path based on the traveling state. The remote controller stops travel of the first work machine upon determining that the first work machine is deviating from the first work path.
A work machine according to a third aspect of the present disclosure includes a work implement, a travel device, and a machine controller that controls the work implement and the travel device. The machine controller acquires a traveling state of the work machine when the work machine is performing work with the work implement while traveling on a work path. The machine controller determines whether the work machine is deviating from the work path based on the traveling state. The machine controller stops travel of the work machine upon determining that the work machine is deviating from the work path.
According to the present disclosure, it is determined whether the work machine is deviating from the work path based on the traveling state. When it is determined that the work machine is deviating from the work path, the travel of the work machine is stopped. As a result, it is possible to prevent the work machine from deviating from the work path.
A control system of a work machine according to an embodiment will be described below with reference to the drawings.
The remote controller 2, the input device 3, the display 4, the operating device 5, and the external communication device 6 are disposed outside of the work machines 1a and 1b. The remote controller 2, the input device 3, the display 4, the operating device 5, and the external communication device 6 may be disposed, for example, in a management center outside of the work machines 1a and 1b. The remote controller 2 remotely controls the work machines 1a and 1b. The number of the work machines remotely controlled by the remote controller 2 is not limited to two and may be greater than two.
The work implement 13 is attached to the vehicle body 11. The work implement 13 includes a lift frame 17, a blade 18, and a lift cylinder 19. The lift frame 17 is attached to the vehicle body 11 so as to be movable up and down. The lift frame 17 supports the blade 18. The blade 18 moves up and down accompanying the movements of the lift frame 17. The lift frame 17 may be attached to the travel device 12. The lift cylinder 19 is coupled to the vehicle body 11 and the lift frame 17. Due to the extension and contraction of the lift cylinder 19, the lift frame 17 moves up and down.
As illustrated in
The power transmission device 24 transmits driving force of the engine 22 to the travel device 12. The power transmission device 24 may be, for example, a hydro static transmission (HST). Alternatively, the power transmission device 24 may be, for example, a transmission having a torque converter or a plurality of transmission gears. Alternatively, the power transmission device 24 may be another type of transmission.
The control valve 27 is disposed between a hydraulic actuator such as the lift cylinder 19 and the hydraulic pump 23. The control valve 27 controls the flow rate of hydraulic fluid supplied from the hydraulic pump 23 to the lift cylinder 19. The control valve 27 may be a pressure proportional control valve. Alternatively, the control valve 27 may be an electromagnetic proportional control valve.
The first work machine 1a includes a machine controller 26a and a machine communication device 28. The machine controller 26a controls the travel device 12 or the power transmission device 24, thereby causing the first work machine 1a to travel. The machine controller 26a controls the control valve 27, thereby causing the blade 18 to move up and down.
The machine controller 26a is programmed to control the first work machine 1a based on acquired data. The machine controller 26a includes a processor 31a and a storage device 32a. The processor 31a is, for example, a central processing unit (CPU). Alternatively, the processor 31a may be a processor that is different from a CPU. The processor 31a executes processes for controlling the first work machine 1a according to programs.
The storage device 32a includes a non-volatile memory such as a ROM and a volatile memory such as a RAM. The storage device 32a may include an auxiliary storage device such as a hard disk or a solid state drive (SSD). The storage device 32a is an example of a non-transitory computer-readable recording medium. The storage device 32a stores computer commands and data for controlling the first work machine 1a.
The machine communication device 28 wirelessly communicates with the external communication device 6. For example, the machine communication device 28 communicates with the external communication device 6 via a wireless LAN such as Wi-Fi (registered trademark), a mobile communication such as 3G, 4G, or 5G, or another type of wireless communication system.
The first work machine 1a includes a position sensor 33. The position sensor 33 may include, for example, a global navigation satellite system (GNSS) receiver such as a global positioning system (GPS). Alternatively, the position sensor 33 may include a receiver of another positioning system. The position sensor 33 may include a ranging sensor such as Lidar, or an image sensor such as a stereo camera. The position sensor 33 outputs position data to the machine controller 26a. The position data indicates a position of the first work machine 1a.
The first work machine 1a includes an orientation sensor 34. The orientation sensor 34 detects a traveling direction of the first work machine 1a. The orientation sensor 34 may include, for example, an inertial measurement unit (IMU). Alternatively, the orientation sensor 34 may include a geomagnetic sensor. Alternatively, the traveling direction of the first work machine 1a may be detected from the change in position of the first work machine 1a detected by the position sensor 33. The orientation sensor 34 outputs orientation data indicative of the traveling direction of the first work machine 1a.
The first work machine 1a includes a left rotation sensor 35L and a right rotation sensor 35R. The left rotation sensor 35L detects the rotation speed of the left crawler belt 16L. The right rotation sensor 35R detects the rotation speed of the right crawler belt 16R. The left rotation sensor 35L outputs rotation speed data indicative of the rotation speed of the left crawler belt 16L. The right rotation sensor 35R outputs rotation speed data indicative of the rotation speed of the right crawler belt 16R.
The external communication device 6 illustrated in
The input device 3 is a device that is operable by an operator. The input device 3 receives an input command from the operator and outputs an operation signal corresponding to the input command to the remote controller 2. The input device 3 outputs the operation signal according to an operation by the operator. The input device 3 outputs the operation signal to the remote controller 2. The input device 3 may include a pointing device such as a mouse or a trackball. The input device 3 may include a keyboard.
The display 4 includes a monitor such as a CRT, an LCD, or an OELD. The display 4 receives an image signal from the remote controller 2. The display 4 displays an image corresponding to the image signal. The display 4 may be integrated with the input device 3. For example, the input device 3 and the display 4 may include, for example, a touch screen.
The operating device 5 is operable by an operator. The operating device 5 includes, for example, a pedal, a lever, or a switch. The operating device 5 is able to remotely control the plurality of work machines 1a and 1b individually. The operating device 5 may specify a portion of the plurality of work machines 1a and 1b to remotely control the portion. The work machines 1a and 1b can be switched between an automatic operation mode and a manual operation mode.
In the automatic operation mode, the work machines 1a and 1b operate automatically without operations by an operator. In the automatic operation mode, the work machines 1a and 1b operate according to a command from the remote controller 2 as described later. Alternatively, in the automatic operation mode, the work machines 1a and 1b operate autonomously and automatically. In that case, the work machines 1a and 1b operate according to determination of the machine controller of each of the work machines 1a and 1b.
In the manual operation mode, the work machines 1a and 1b operate according to an operation signal from the operating device 5. The operating device 5 receives an operation by an operator and outputs an operation signal corresponding to the operation. The operation signal is transmitted to the plurality of work machines 1a and 1b via the external communication device 6.
The remote controller 2 remotely controls the work machines 1a and 1b. The remote controller 2 receives an operation signal from the input device 3. The remote controller 2 outputs an image signal to the display 4. The remote controller 2 includes a processor 2a and a storage device 2b. The processor 2a is, for example, a central processing unit (CPU). Alternatively, the processor 2a may be a processor that is different from a CPU. The processor 2a executes processes for controlling the work machines 1a and 1b according to programs. In the following description, the description regarding the processes executed by the remote controller 2 may be interpreted as the processes executed by the processor 2a.
The storage device 2b includes a non-volatile memory such as a ROM and a volatile memory such as a RAM. The storage device 2b may include an auxiliary storage device such as a hard disk or a solid state drive (SSD). The storage device 2b is an example of a non-transitory computer-readable recording medium. The storage device 2b stores computer commands and data for controlling the work machines 1a and 1b.
Next, automatic operation of the work machines 1a and 1b executed by the control system 100 will be described.
As illustrated in
In step S102, the remote controller 2 acquires position data. The position data includes first position data of the first work machine 1a and second position data of the second work machine 1b. The first position data indicates a position of the first work machine 1a. The second position data indicates a position of the second work machine 1b.
In step S103, the remote controller 2 determines a plurality of work areas 50A and 50B at the work site.
The second work area 50B is adjacent to the first work area 50A. The second work area 50B includes a plurality of second work paths 54 to 56. The plurality of second work paths 54 to 56 extend in a predetermined second work direction D2. The plurality of second work paths 54 to 56 extend linearly. The second work paths 54 to 56 are aligned in the lateral direction of the second work area 50B. The lateral direction of the second work area 50B is the direction intersecting the second work direction D2. In the example illustrated in
The remote controller 2 may determine the work areas 50A and 50B according to an operation of the input device 3 by an operator. Alternatively, the remote controller 2 may automatically determine the work areas 50A and 50B.
The alignment of the work paths 51 to 56 is not limited to that illustrated in
In step S104, the remote controller 2 allocates the work areas 50A and 50B to the work machines 1a and 1b. The operator allocates the work area 50A to one of the wok machines 1a and 1b and allocates the work area 50B to the other one using the input device 3. The remote controller 2 determines the work machines to be allocated to the respective work areas 50A and 50B based on the operation signal from the input device 3.
Alternatively, the remote controller 2 may automatically determine the work machines to be allocated to the respective plurality of work areas 50A and 50B. In the example illustrated in
In step S105, the remote controller 2 determines whether an approval to start work has been received. The operator can instruct an approval to start work by the work machines 1a and 1b using the input device 3. The remote controller 2 determines whether the approval has been received based on the operation signal from the input device 3. The remote controller 2 may determine whether the approval has been received for each of the work machines 1a and 1b individually.
In step S106, the remote controller 2 transmits a work start command to the work machines 1a and 1b. Accordingly, the first work machine 1a is controlled to perform work according to the alignment of the allocated first work paths 51 to 53. The remote controller 2 transmits data indicative of positions of the first work paths 51 to 53 to the first work machine 1a. The remote controller 2 transmits data indicative of positions of the second work paths 54 to 56 to the second work machine 1b.
The first work machine 1a moves to the first work paths 51 to 53 allocated to the first work machine 1a and automatically aligns its position and orientation with respect to the first work paths 51 to 53. Then, the first work machine 1a performs digging while moving along the first work paths 51 to 53. As a result, slots are formed along the respective first work paths 51 to 53. When the digging of the first work paths 51 to 53 is completed, digging walls are left between the first work paths 51 to 53. The first work machine 1a performs digging of the digging walls while moving along allocated first digging wall areas 61 and 62. The order of digging of the first work paths 51 to 53 or the order of digging of the first digging wall areas 61 and 62 may be determined by the remote controller 2. Alternatively, the order of digging of the first work paths 51 to 53 or the order of digging of the first digging wall areas 61 and 62 may be determined by the machine controller 26a of the first work machine 1a.
Similarly, the second work machine 1b moves to the second work paths 54 to 56 allocated to the second work machine 1b and automatically aligns its position and orientation with respect to the second work paths 54 to 56. Then, the second work machine 1b performs digging while moving along the second work paths 54 to 56. When the digging of the second work paths 54 to 56 is completed, digging walls are left between the second work paths 54 to 56. The second work machine 1b performs digging of the digging walls while moving along allocated second digging wall areas 63 and 64. The order of digging of the second work paths 54 to 56 or the order of digging of the second digging wall areas 63 and 64 may be determined by the remote controller 2. Alternatively, the order of digging of the second work paths 54 to 56 or the order of digging of the second digging wall areas 63 and 64 may be determined by the machine controller of the second work machine 1b.
For example, as illustrated in
By repeating such work, the first work machine 1a digs the actual topography 80 so that the actual topography 80 has a shape along the target design topography 84. The second work machine 1b also performs digging in the same manner as the first work machine 1a. Upon completing the digging of the target design topography 84, the work machines 1a and 1b dig a next target design topography 85 positioned below the target design topography 84. The work machines 1a and 1b repeat the above work until they reach a final target topography 81 or its vicinity.
Next, control for preventing the work machines 1a and 1b in the automatic operation mode from deviating from the work paths 51 to 56 (hereinafter referred to as “deviation prevention control”) will be described.
The traveling state includes the current positions of the work machines 1a and 1b, the traveling directions of the work machines 1a and 1b, and the rotation speeds of the left and right crawler belts of the work machines 1a and 1b. The remote controller 2 acquires the current position of each of the work machines 1a and 1b from the position data of each of the work machines 1a and 1b. The remote controller 2 acquires the traveling direction of each of the work machines 1a and 1b from the orientation data of each of the work machines 1a and 1b. The remote controller 2 acquires the current position of each of the work machines 1a and 1b from the position data of each of the work machines 1a and 1b. The remote controller 2 acquires the rotation speeds of the left and right crawler belts of each of the work machines 1a and 1b from the rotation speed data of each of the work machines 1a and 1b.
In step S202, the remote controller 2 determines an object of the deviation prevention control. The remote controller 2 determines whether each of the plurality of work machines 1a and 1b repeatedly travels on a same work path. When there are the work machine 1a repeatedly traveling on the same work path and the work machine 1b repeatedly traveling on the same work path, the remote controller 2 determines the work machines 1a and 1b as an object of the deviation prevention control. For example, when the work machines 1a and 1b are traveling on the same work paths for a predetermined period of time as the work paths on which they have traveled in the previous work, the remote controller 2 determines that the work machines 1a and 1b are repeatedly traveling on the same work paths. That is, the remote controller 2 determines the work machines 1a and 1b that are digging the slots by slot dozing as the object of the deviation prevention control. Therefore, for example, the remote controller 2 excludes the work machines 1a and 1b that are moving toward the allocated work areas from the object of the deviation prevention control.
In step S203, the remote controller 2 determines whether the work machine that is the object of the deviation prevention control is deviating from the work path. For example, when the first work machine 1a is traveling on the first work path 51 and is the object of the deviation prevention control, the remote controller 2 determines whether the first work machine 1a is deviating from the first work path 51. Further, when the second work machine 1b is traveling on the second work path 54 and is the object of the deviation prevention control, the remote controller 2 determines whether the second work machine 1b is deviating from the second work path 54. The remote controller 2 determines whether the first work machine 1a is deviating from the first work path 51 based on the traveling state of the first work machine 1a. The remote controller 2 determines whether the second work machine 1b is deviating from the second work path 54 based on the traveling state of the second work machine 1b.
The remote controller 2 determines that the work machines 1a and 1b are deviating from the work path when at least one of first to third conditions is satisfied. A first condition is that a state where the traveling directions of the work machines 1a and 1b are deviating from the target orientations of the work machines 1a and 1b continues for a predetermined period of time. For example, the target orientation of the first work machine 1a is the first work direction D1. The target orientation of the second work machine 1b is the second work direction D2.
A second condition is that a deviation width of the current positions of the work machines 1a and 1b from the work paths exceed a threshold. For example, as illustrated in
In step S204, the remote controller 2 stops travel of the deviating work machine. For example, upon determining that the first work machine 1a is deviating from the first work path 51, the remote controller 2 stops the travel of the first work machine 1a.
In step S205, the remote controller 2 stops travel of the work machine positioned in a predetermined range. The predetermined range is the work area adjacent to the work area of the deviating work machine. For example, upon determining that the first work machine 1a is deviating from the first work path 51, the remote controller 2 stops the travel of the first work machine 1a. The remote controller 2 also stops travel of the second work machine 1b positioned in the second work area 50B adjacent to the first work area 50A. In this case, the remote controller 2 stops the travel of the second work machine 1b even if the second work machine 1b is not deviating from the second work path 54.
In step S206, the remote controller 2 switches the work machines 1a and 1b stopped in steps S204 and S205 from the automatic operation mode to the manual operation mode. Accordingly, the operator can manually operate the stopped work machines 1a and 1b using the operating device 5.
In the control system 100 of the work machines 1a and 1b according to the present embodiment described above, it is determined whether the work machines 1a and 1b are deviating from the work paths 51 and 54 based on the traveling state. When it is determined that the work machines 1a and 1b are deviating from the work paths 51 and 54, the travel of the work machines 1a and 1b is stopped. As a result, the work machines 1a and 1b can be prevented from deviating from the work paths 51 and 54.
Although an embodiment has been described so far, the present invention is not limited to the above embodiment and various modifications can be made without departing from the gist of the invention. The work machines 1a and 1b are not limited to bulldozers and may be other vehicles such as wheel loaders or motor graders. The work machines 1a and 1b may be a vehicle driven by an electric motor.
The remote controller 2 may have a plurality of controllers that are separate from each other. The processes by the remote controller 2 may be distributed and executed among the plurality of controllers. The machine controller 26a may have a plurality of controllers that are separate from each other. The processes by the machine controller 26a may be distributed and executed among the plurality of controllers. The above-mentioned processes may be distributed and executed by a plurality of processors.
The processes of the automatic operation and the processes of the deviation prevention control are not limited to those of the above-mentioned embodiment and may be changed, omitted, or added. The execution order of the processes of the automatic operation and the execution order of the processes of the deviation prevention control are not limited to those of the above-mentioned embodiment and may be changed.
When determining that the work machines 1a and 1b have deviated from the work paths 51 and 54, the remote controller 2 may output a warning. The warning may be an image or text displayed on the display 4. Alternatively, the warning may be a sound. The deviation prevention control may be applied not only when the work machines 1a and 1b are traveling forward on the work paths 51 and 54, but also when they are traveling in reverse.
A portion of the processes by the machine controller 26a may be executed by the remote controller 2. A portion of the processes by the remote controller 2 may be executed by the machine controller 26a. For example, the processes of the automatic operation may be executed by each of the machine controllers of the work machines 1a and 1b. The processes of the deviation prevention control may be executed by each of the machine controllers of the work machines 1a and 1b.
According to the present disclosure, it is possible to prevent the work machine from deviating from the work path.
1
a First work machine
1
b Second work machine
2 Remote controller
6 Communication device
12 Travel device
13 Work implement
16L Left crawler
16R Right crawler
26
a Machine controller
51 First work path
| Number | Date | Country | Kind |
|---|---|---|---|
| 2020-148850 | Sep 2020 | JP | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/JP2021/025661 | 7/7/2021 | WO |
