JP7575065B2 - Remote control system, remote operation device, and remote control method for a work vehicle - Google Patents

Description

The present invention relates to a remote control system, a remote operation device, and a remote control method for a work vehicle, and is particularly suitable for use in a system that remotely controls the travel of a work vehicle.

In recent years, as the farm population declines, farmland has been concentrated among farmers and the scale of operations has expanded. As a result, it is predicted that it will become difficult to secure skilled workers in the future. Under these circumstances, there is a need to realize highly productive agricultural work techniques that can handle the large number of fields that come with the expansion of scale with a limited number of personnel. For example, there is hope for the development of technology that can increase the working area per worker by utilizing autonomous work vehicles.

In this regard, a system for remotely controlling the driving of an autonomous work vehicle is known (see, for example, Patent Document 1). In the work vehicle operation system described in Patent Document 1, a changeover switch is provided inside the cabin of the work vehicle to switch between a remote operation mode in which the work vehicle is controlled based on a signal received from a tablet terminal, and a manual operation mode in which signals received from the tablet terminal are not reflected in the control of the work vehicle, and the operation of the remote operator or the passenger is reflected in the operation of the work vehicle depending on the set mode, thereby preventing the work vehicle from behaving in an unexpected manner when the passenger and the remote operator perform different operations.

This patent document 1 discloses that after an emergency situation has been avoided, a changeover switch can be operated to return from manual operation mode to remote operation mode, that the remote operation mode can be automatically restored if no operation of an operation member is detected for a certain period of time after the operation of an operation member in manual operation mode, and that the remote operation mode can be restored when a signal to return to the remote operation mode is received from a tablet terminal.

JP 2018-108764 A

In the work vehicle operation system described in Patent Document 1, the work vehicle is remotely controlled by operating a tablet terminal. In contrast, in order to allow the remote operator to remotely operate the work vehicle with a feeling close to that of actually operating an actual work vehicle, the steering may be configured to imitate that which is actually equipped on the work vehicle.

In this case, when switching from manual operation mode to remote operation mode as in Patent Document 1, the turning curvature corresponding to the steering angle of the steering of the manually operated work vehicle (the actual steering angle at the time of switching from the manual operation mode to the remote operation mode) may not match the turning curvature corresponding to the steering angle of the simulated steering for remote operation. If the steering of the work vehicle is remotely controlled by operating the simulated steering in such a state, the turning curvature of the work vehicle that the remote operator is aware of while operating the simulated steering differs from the actual turning curvature of the work vehicle, resulting in a problem in which the steering control cannot be performed correctly as intended.

The present invention was made to solve such problems, and aims to enable a remote control system that remotely controls the steering of a work vehicle using a simulated steering wheel for remote steering control to perform correct steering control as intended by the remote operator after switching from other driving mode to remote controlled driving mode.

In order to solve the above problems, the present invention provides a remote control system that controls the travel of a work vehicle by instructions given to a vehicle control device of the work vehicle from a remote control device including a simulated steering for remote steering control. When switching from another driving mode to a remote controlled driving mode, the system detects the difference between the actual turning curvature of the work vehicle and the turning curvature corresponding to the steering angle of the simulated steering, and if a turning curvature difference exceeding a predetermined value is detected, the remote control device transmits steering control instructions to the vehicle control device in a state where the turning curvature difference exceeding the predetermined value is eliminated.

According to the present invention configured as described above, when the other driving mode is switched to the remote controlled driving mode, even if the actual turning curvature of the work vehicle at the time of the switch does not match the turning curvature corresponding to the steering angle of the simulated steering, the remote control device transmits a steering control command to the vehicle control device in a state where the mismatch is resolved. As a result, the turning curvature that the remote operator is aware of while operating the simulated steering matches the actual turning curvature of the work vehicle, so that the correct steering control can be performed as intended by the remote operator.

1 is a diagram showing an example of the overall configuration of a remote control system for a work vehicle according to an embodiment of the present invention; 2 is a block diagram showing an example of a functional configuration of a vehicle control device and a remote control device according to the present embodiment. FIG. 2 is a diagram illustrating an example of a hardware configuration of an operation unit included in the remote control device of the present embodiment. FIG. 4 is a diagram showing an example of a monitoring screen displayed on a display by a monitoring screen display control unit of the present embodiment; FIG. 5A and 5B are diagrams illustrating an example of the operation of a differential control unit according to the present embodiment. 5 is a flowchart showing an example of the operation of the remote control device according to the present embodiment.

An embodiment of the present invention will be described below with reference to the drawings. Fig. 1 is a diagram showing an example of the overall configuration of a remote control system for a work vehicle according to this embodiment (hereinafter simply referred to as a remote control system). As shown in Fig. 1, the remote control system of this embodiment is configured with vehicle control devices _10-1 to _10-4 (hereinafter simply referred to as vehicle control devices 10 when not particularly distinguished from each other) mounted on a plurality of work vehicles _100-1 to _100-4 (hereinafter simply referred to as work vehicles 100 when not particularly distinguished from each other), and a remote operation device 20 present in a base station 200 located outside the work vehicles _100-1 to _100-4 .

The work vehicles _100-1 to _100-4 are respectively equipped with work machines _101-1 to _101-4 (in the following description, when there is no particular need to distinguish between them, they will simply be referred to as work machines 101). The work machine 101 can be any type, but as an example in this embodiment, it is a tiller that is connected to the rear of the vehicle body when used. The work machine 101 is configured to be able to rise and fall in the vertical direction, and is lowered when working and raised when not working.

The vehicle control device 10 and the remote control device 20 are connected via wireless communication means such as a wireless LAN, and are capable of communicating with each other. In the remote control system of this embodiment, the driving and work of the multiple work vehicles 100 are controlled by instructions given from the remote control device 20 to each of the multiple vehicle control devices 10. In addition, a monitoring screen for monitoring the driving of the multiple vehicle control devices 10 is displayed on the remote control device 20 based on status information (described in detail below) sent from the multiple vehicle control devices 10 to the remote control device 20, and the movement of the steering wheel 31 provided in the remote control device 20 is controlled (these operations are also described in detail below).

In this embodiment, an example of a system that can run one to a maximum of four work vehicles 100 simultaneously by remote control is described, but a maximum of four is merely an example, and two or more vehicles may be used. Furthermore, the remote control system of this embodiment may be a system that runs only one work vehicle 100 by remote control. Alternatively, a configuration in which multiple remote operation devices 20 exist may be used.

Figure 2 is a block diagram showing an example of the functional configuration (including a part of the hardware configuration) of the vehicle control device 10 and the remote control device 20. As shown in Figure 2, the vehicle control device 10 has, as its functional configuration, a wireless communication unit 11, a mode setting unit 12, a driving control unit 13, and a status information transmission unit 14. The vehicle control device 10 also has a route data storage unit 111 as a storage medium. In addition, various sensors 112 are electrically connected to the vehicle control device 10.

Each of the functional blocks 11 to 14 can be configured using either hardware, a DSP (Digital Signal Processor), or software. For example, when configured using software, each of the functional blocks 11 to 14 is actually configured with a computer's CPU, RAM, ROM, etc., and is realized by the operation of a program stored in a recording medium such as the RAM, ROM, hard disk, or semiconductor memory.

Furthermore, the remote control device 20 has, as its functional configuration, a wireless communication unit 21, a mode control unit 22, a remote operation instruction unit 23, a status information receiving unit 24, a monitoring screen display control unit 25, a turning curvature difference detection unit 26, and a difference control unit 27. Further, the remote control device 20 has, as its hardware configuration, an operation unit 211 and a display 212. Further, the remote control device 20 has, as a storage medium, a route data storage unit 213.

Each of the functional blocks 21 to 27 can be configured using hardware, a DSP, or software. For example, when configured using software, each of the functional blocks 21 to 27 is actually configured with a computer's CPU, RAM, ROM, etc., and is realized by the operation of a program stored in a recording medium such as the RAM, ROM, hard disk, or semiconductor memory.

The wireless communication unit 11 of the vehicle control device 10 and the wireless communication unit 21 of the remote control device 20 communicate wirelessly with each other. The wireless communication units 11, 21 transmit various instruction information for controlling the travel and work of multiple work vehicles 100 from the remote control device 20 to the vehicle control device 10. In addition, the wireless communication units 11, 21 transmit various status information detected by various sensors 112 of the vehicle control device 10 from the vehicle control device 10 to the remote control device 20.

The mode setting unit 12 of the vehicle control device 10 sets the mode related to the driving of the work vehicle 100. In this embodiment, the four modes that can be set are an autonomous driving mode in which the vehicle autonomously drives along a preset driving route by automatic steering control, a remotely controlled driving mode in which the vehicle remotely drives according to instructions including steering control received from the remote control device 20 (hereinafter referred to as remote control instructions), a manual driving mode in which the worker actually boards the work vehicle 100 and drives the work vehicle 100 using various controls provided on the work vehicle 100, and a standby mode in which the work vehicle 100 is in a standby state without performing any of the autonomous driving, remotely controlled driving, and manual driving. The autonomous driving mode, manual driving mode, and standby mode correspond to the "other driving modes" in the claims.

The mode setting unit 12 sets and cancels the manual driving mode based on a manual driving mode setting switch provided on the vehicle control device 10. When the mode setting unit 12 sets or cancels the manual driving mode, it notifies the remote control device 20. Hereinafter, this notification is referred to as a manual driving mode switching notification.

For example, the mode setting unit 12 sets the manual driving mode when the setting switch is turned on. Also, the mode setting unit 12 cancels the manual driving mode when the setting switch is turned off, and sets, for example, a standby mode. The reason why the manual driving mode is controlled to be turned on/off by the setting switch of the work vehicle 100 is to prevent the manual driving mode from being arbitrarily switched from another mode to the manual driving mode or from the manual driving mode to another mode by remote operation of the remote control device 20 when there is no operator in the driver's seat of the work vehicle 100 or when the operator is not aware of it.

The mode setting unit 12 sets either the autonomous driving mode, the remotely controlled driving mode, or the standby mode according to an instruction (hereinafter, referred to as the mode setting instruction) received from the remote control device 20. In the initial state immediately after the power of the vehicle control device 10 is turned on, the mode setting unit 12 sets the manual driving mode. The mode setting unit 12 then sets either the autonomous driving mode, the remotely controlled driving mode, or the standby mode according to the mode setting instruction received from the remote control device 20. Here, the mode setting unit 12 is only able to select the standby mode, the remotely controlled driving mode, or the autonomous driving mode after the manual driving mode is released by a setting switch provided on the vehicle control device 10. This is done in consideration of safety immediately after the power is turned on.

The driving control unit 13 executes driving control, including steering, of the work vehicle 100 according to the mode set by the mode setting unit 12. When the autonomous driving mode is set by the mode setting unit 12, the driving control unit 13 detects the deviation of the vehicle position and orientation from the driving route based on the data of the driving route stored in the route data storage unit 111 and the current position and current orientation (hereinafter referred to as the vehicle position and orientation) of the work vehicle 100 detected by the position and orientation sensor included in the various sensors 112, and automatically controls the steering of the work vehicle 100 so as to reduce the deviation. In addition, when the autonomous driving mode is set, the driving control unit 13 automatically executes control related to driving other than steering, such as the driving speed and gear changes of the work vehicle 100. In other words, after starting autonomous driving, the driving control unit 13 automatically controls all driving without receiving instructions from the remote control device 20.

The route data storage unit 111 stores route data representing a travel route set in advance in the field on which the work vehicle 100 travels. This route data is transmitted from the remote control device 20 to the vehicle control device 10 before the work vehicle 100 starts traveling, and is stored in the route data storage unit 111. The method of storing route data in the route data storage unit 111 is not limited to the wireless transmission as described above. For example, a removable storage medium storing route data may be connected to the vehicle control device 10, and the data may be transferred from the removable storage medium to the route data storage unit 111. The route data storage unit 111 may further store data (hereinafter referred to as field data) used to display an overhead image of the field on a monitoring screen described later. The route data storage unit 111 may further store map data of the field. The map data of the field can be used, for example, as data for monitoring whether the work vehicle 100 has deviated from the field.

When the remotely controlled driving mode is set by the mode setting unit 12, the driving control unit 13 executes driving control of the work vehicle 100 according to remote driving instructions transmitted from the remote control device 20. In this case, the remote driving instructions include instructions regarding starting and stopping the engine, instructions regarding starting and stopping driving, instructions regarding steering control, instructions regarding driving speed control, instructions regarding gear shift control, etc.

When the autonomous driving mode or remotely controlled driving mode is set by the mode setting unit 12, the driving control unit 13 also controls the lifting and driving of the work machine 101 provided on the work vehicle 100. When the autonomous driving mode is set, the driving control unit 13 automatically controls the lifting and driving of the work machine 101 at a set timing according to the work data stored together with the route data in the route data storage unit 111. On the other hand, when the remotely controlled driving mode is set, the driving control unit 13 controls the lifting and driving of the work machine 101 according to remote control instructions transmitted from the remote operation device 20.

When the manual driving mode is set by the mode setting unit 12, the driving control unit 13 executes driving control of the work vehicle 100 in accordance with the operation of the steering wheel, pedals, gear lever, and other controls of the work vehicle 100 by the worker aboard the work vehicle 100, and also controls the lifting and driving of the work machine 101 equipped on the work vehicle 100.

When the standby mode is set by the mode setting unit 12, the travel control unit 13 puts the transmission in neutral to idle while keeping the engine running, and stops the work vehicle 100. In addition, the power to the PTO shaft is stopped by the PTO clutch, and the work equipment 101 is raised to the upper home position and waits. As described below, when the standby mode is set, no remote control instructions are sent from the remote control device 20 to the vehicle control device 10. Therefore, the vehicle control device 10 does not run the work vehicle 100 or operate the work equipment 101 in accordance with the remote control instructions.

The status information transmission unit 14 sequentially transmits to the remote control device 20 driving status information indicating the driving status of the work vehicle 100 detected by the various sensors 112, and work status information indicating the working status of the work implement 101 detected by the various sensors 112. The driving status information includes, for example, the vehicle position and direction of the work vehicle 100, steering angle (corresponding to the steering-related value in the claims), driving speed, gear ratio, engine speed, engine load factor, vehicle body inclination angle (roll angle and pitch angle), remaining fuel, coolant temperature, battery voltage, vehicle surroundings image, etc. The work status information also includes, for example, the height of the work implement 101, PTO speed, etc.

The various sensors 112 include a number of sensors necessary to acquire the above-mentioned driving condition information and work condition information. Here, each of the multiple work vehicles 100 is equipped with a camera that captures images of the surroundings of the work vehicle 100 as one of the various sensors 112. In this embodiment, as an example, six cameras are mounted to capture images of the front, rear, left, right, left diagonally rear, and right diagonally rear of the work vehicle 100. The installation position and installation angle of the front camera that captures images of the front of the work vehicle 100 are adjusted so that the capture range includes a part of the vehicle body. The installation position and installation angle of the rear camera that captures images of the rear of the work vehicle 100 are adjusted so that the capture range includes the work equipment 101.

The mode control unit 22 of the remote control device 20 controls the setting of modes (autonomous driving mode, remotely controlled driving mode, standby mode) for multiple vehicle control devices 10 according to the operation of the operation unit 211 by the operator (remote operator) of the remote control device 20. In this embodiment, the mode control unit 22 stores information on which mode is set for which work vehicle 100. In addition, when the wireless communication unit 21 receives a manual driving mode switching notification from the vehicle control device 10, the mode control unit 22 stores information on either the manual driving mode or the standby mode according to the content of the notification. Then, when the stored mode information is switched from another driving mode to the remotely controlled driving mode, the mode control unit 22 notifies the turning curvature difference detection unit 26 of this.

The mode control unit 22 controls the setting of the modes for the multiple vehicle control devices 10 so that the remotely controlled travel mode is not set for two or more vehicle control devices 10 at the same time while the multiple work vehicles 100 are traveling in any mode. Specifically, when the remotely controlled travel mode is set for the vehicle control device 10 _-i of one work vehicle 100 _-i (i = any one of 1 to 4), the mode control unit 22 prevents the operation of setting the remotely controlled travel mode for the vehicle control device 10 _-j of the other work vehicles 100 _-j (j = any one of 1 to 4. j ≠ i) from being performed, and prevents the transmission of a mode setting instruction for setting the remotely controlled travel mode to the vehicle control device 10 _-j of the other work vehicles 100 _-j . At this time, the travel control units 13 provided in the vehicle control devices 10 _-1 to 10 _-4 of the multiple work vehicles 100 _-1 to 100 _-4 continue travel control, including steering, of the work vehicles 100 _-1 to 100 _-4 according to the mode already set by the mode setting unit 12.

The remote operation instruction unit 23 transmits various remote operation instructions to the vehicle control device 10 _-i of the work vehicle 100 _- i in which the remote operation travel mode is set, in accordance with the operation of the operation unit 211 by the remote operator. As described above, the remote operation instructions include instructions related to starting and stopping the engine of the work vehicle 100, instructions related to starting and stopping travel, instructions related to steering control, instructions related to travel speed control, instructions related to gear shift control, instructions related to raising and lowering the work machine 101, instructions related to driving the work machine 101, and the like.

Figure 3 is a diagram showing an example of the hardware configuration of the operation unit 211. As shown in Figure 3, the operation unit 211 of this embodiment includes a steering wheel 31, pedals 32, a group of switches 33, and a gear shift lever 34. The steering wheel 31, pedals 32, and gear shift lever 34 are configured to imitate those actually provided on the work vehicle 100. This allows the remote operator to operate the operation unit 211 with a feeling close to that of actually operating the actual work vehicle 100. The steering wheel 31 corresponds to the "simulated steering wheel" in the claims.

The switch group 33 includes a vehicle selection switch 331 for selecting one of the multiple work vehicles _100-1 to _100-4 , and a mode selection switch 332 for selecting one of the autonomous driving mode, the remote controlled driving mode, or the standby mode. This mode selection switch 332 does not include a switch for selecting the manual driving mode. When setting a mode other than the manual driving mode for the work vehicle 100, first operate the vehicle selection switch 331 to select one of the work vehicles _100-1 to _100-4 , and then operate the mode selection switch 332 to select the desired mode. When such an operation is performed, the mode control unit 22 transmits a mode setting instruction to the vehicle control device 10 of the work vehicle 100 selected by the mode selection switch 332, for setting the mode selected by the mode selection switch 332.

However, when the remotely controlled travel mode is set for the vehicle control device 10 _-i of one work vehicle 100 _-i , even if an operation is performed using the vehicle selection switch 331 to select another work vehicle 100 _-j , the mode control unit 22 invalidates that operation and does not accept operation of the mode selection switch 332 to select that other work vehicle 100 _-j . In this case, the mode control unit 22 does not transmit a mode setting instruction to set the remotely controlled travel mode to the vehicle control device 10 _-j of the other work vehicle 100 _-j .

In addition, when the remotely controlled travel mode is set for the vehicle control device 10 _-i of one work vehicle 100 _-i , and after another work vehicle 100 _-j is selected using the vehicle selection switch 331, when an operation to select the remotely controlled travel mode is performed using the mode selection switch 332, the mode control unit 22 may be configured to disable the selection operation of the remotely controlled travel mode.

For example, when the remotely controlled travel mode is set for the vehicle control device _10-1 of the first work vehicle _100-1 , if an operation to set the remotely controlled travel mode is performed for the vehicle control device _10-2 of the second work vehicle _100-2 , the mode control unit 22 invalidates the operation and prevents a mode setting instruction for setting the remotely controlled travel mode from being transmitted to the vehicle control device _10-2 of the second work vehicle _100-2 . At this time, the travel control unit 13 of the first work vehicle _100-1 continues to control the travel of the first work vehicle _100-1 according to the remotely controlled travel mode already set by the mode setting unit 12. In addition, the travel control units 13 of the second to fourth work vehicles _100-2 to _100-4 continue to control the travel of each of the work vehicles _100-2 to _100-4 according to the autonomous travel mode, manual travel mode, or standby mode already set by the mode setting unit 12.

The switch group 33 further includes various switches 333 for instructing the starting and stopping of the engine of the work vehicle 100, starting and stopping travel, raising and lowering the work machine 101, and driving the work machine 101. When a work vehicle 100 in which the remote control travel mode is set is selected by operating the vehicle selection switch 331 and the remote operator operates the various switches 333, instruction information corresponding to the operated switch is generated by the remote control instruction unit 23. The remote control instruction unit 23 transmits a remote control instruction including this instruction information to the work vehicle 100 selected by the vehicle selection switch 331 (the work vehicle 100 in which the remote control travel mode is set).

The switch group 33 further includes an emergency switch 334. When the emergency switch 334 is operated by the remote operator, the mode control unit 22 simultaneously transmits a mode setting instruction to set the standby mode to the vehicle control devices 10 of all the work vehicles 100. For example, when an obstacle such as a person or an animal appears around the work vehicle 100 and an emergency stop is required, the travel and work of all the work vehicles 100 can be immediately stopped by operating the emergency switch 334. It is also possible to stop only the work vehicle 100 around which an obstacle has appeared by selecting the work vehicle 100 around which an obstacle has appeared using the vehicle selection switch 331 and then setting the standby mode by operating the mode selection switch 332, but when a highly urgent situation occurs, the work vehicle 100 can be made to make an emergency stop by operating only one emergency switch 334.

Here, the vehicle control devices 10 of all work vehicles 100 are configured to be in standby mode when the emergency switch 334 is operated, but this is not limited to the above. For example, a separate emergency stop mode may be provided to which the work vehicles 100 transition when the emergency switch 334 is operated, and the engines of the work vehicles 100 may be stopped and the parking brakes may be activated.

For a work vehicle 100 that is set to manual driving mode, it is preferable not to switch to standby mode or emergency stop mode even if the emergency switch 334 is operated on the remote control device 20. This is because it is dangerous to suddenly stop the work vehicle 100 regardless of the intentions of the worker (manual operator).

The steering wheel 31 is held by the remote operator. When the remote operator rotates the steering wheel 31 to the left or right while a work vehicle 100 in which the remotely controlled travel mode is set is selected by operating the vehicle selection switch 331, steering information indicating the steering direction and steering amount is generated by the remote control instruction unit 23. The remote control instruction unit 23 transmits a remote control instruction including this steering information to the work vehicle 100 selected by the vehicle selection switch 331 (the work vehicle 100 in which the remotely controlled travel mode is set).

The rotation angle (hereinafter referred to as the left/right rotation angle) of the steering wheel 31 from the left lock (when rotated to the left as far as possible) to the right lock (when rotated to the right as far as possible) does not necessarily have to match the left/right rotation angle of the actual steering wheel of the work vehicle 100.

If the left and right rotation angles of the steering wheel 31 do not match the left and right rotation angles of the actual steering wheel of the work vehicle 100, the steering amount of the steering wheel 31 may be converted to the actual steering amount of the work vehicle 100, and steering information indicating the converted steering amount may be transmitted. Alternatively, the steering amount of the steering wheel 31 may be transmitted as steering information, and the work vehicle 100 that receives it may convert it to the actual steering amount. This conversion is performed, for example, according to a function or table information that results in a relationship in which the turning curvature of the work vehicle 100 corresponding to the left and right rotation angles of the steering wheel 31 matches the turning curvature of the work vehicle 100 corresponding to the actual left and right rotation angles of the steering wheel of the work vehicle 100.

As shown in FIG. 3, the steering wheel 31 has a structure that makes it easy to visually understand how far the remote operator is turning it to the left or right. That is, the steering wheel 31 has two spokes 31b extending left and right from a central horn pad 31a, and when the spokes 31b are horizontal as shown in FIG. 3, it can be intuitively understood that the steering angle of the steering wheel 31 is 0 degrees.

The pedals 32 are used by the remote operator by stepping on them with his/her feet, and include independent brake and accelerator pedals on the left and right. When the remote operator steps on the pedals 32 while a work vehicle 100 in which the remotely controlled driving mode is set is selected by operating the vehicle selection switch 331, pedal operation information indicating either a deceleration operation for the left wheel, a deceleration operation for the right wheel, or an acceleration operation for both the left and right wheels is generated by the remote control instruction unit 23. The remote control instruction unit 23 transmits a remote control instruction including this pedal operation information to the work vehicle 100 selected by the vehicle selection switch 331 (a work vehicle 100 in which the remotely controlled driving mode is set).

The gear shift lever 34 is held by the remote operator. When the remote operator operates the gear shift lever 34 while a work vehicle 100 in which the remotely controlled travel mode is set is selected by operating the vehicle selection switch 331, gear shift information indicating the gear specified by the operation is generated by the remote control instruction unit 23. The remote control instruction unit 23 transmits a remote control instruction including this gear shift information to the work vehicle 100 selected by the vehicle selection switch 331 (the work vehicle 100 in which the remotely controlled travel mode is set).

When a work vehicle 100 in which the remote control driving mode is not set is selected by operating the vehicle selection switch 331, the remote control instruction unit 23 will not transmit a remote control instruction even if the steering wheel 31, pedals 32, various switches 333, and gear shift lever 34 are operated.

The status information receiving unit 24 sequentially receives the status information (traveling status information and work status information) transmitted from the status information transmitting units 14 of the multiple work vehicles 100. The status information receiving unit 24 supplies the received status information to the monitoring screen display control unit 25. In addition, the status information receiving unit 24 supplies information indicating the actual steering angle of the work vehicle 100 (hereinafter referred to as actual steering angle information) from the received status information to the turning curvature difference detection unit 26.

The monitoring screen display control unit 25 generates a monitoring screen for monitoring the traveling and working states of the multiple work vehicles 100 based on the field data and route data stored in the route data storage unit 213 and status information (traveling status information and working status information) sent from the work vehicles 100, and displays it on the display 212. The field data and route data stored in the route data storage unit 213 are field data for the fields on which the multiple work vehicles 100 _-1 to 100 _-4 each travel, and route data representing the traveling routes set for each of the multiple work vehicles 100 _-1 to 100 _-4 .

Fig. 4 is a diagram showing an example of a monitoring screen displayed on the display 212. As shown in Fig. 4, this embodiment has three displays _212-1 to _27-3 , each of which displays a different monitoring screen. These three displays _212-1 to _27-3 are arranged side by side in the horizontal direction in front of the operation unit 211 operated by the remote operator, so that the operation unit 211 can be operated while checking the monitoring screens displayed on the displays _212-1 to _27-3 .

The first display _212-1 shown in Fig. 4(a) is for displaying an overhead image showing the travel positions of the multiple work vehicles _100-1 to _100-4 in the field. A screen 401 on the left side of the first display _212-1 displays an image of an overall map including the multiple fields on which the multiple work vehicles _100-1 to 100-4 are travelling. Four _- split screens 402 to 405 on the right side of the first display _212-1 each display an enlarged and individual image of the multiple fields (particularly the area within a predetermined range from the work vehicle 100) on which the multiple work vehicles _100-1 to _100-4 are travelling.

The monitoring screen display control unit 25 displays a field image using the field data stored in the route data storage unit 213, and also displays a vehicle image superimposed on the field image based on the vehicle position and orientation information of the work vehicles 100 _-1 to 100 _-4 acquired by the status information receiving unit 24. As the work vehicles 100 _-1 to 100 _-4 actually travel, the display position of the vehicle image on the field image is successively updated, so that the remote operator can get an overview of where in the field each of the work vehicles 100 _-1 to 100 _-4 is traveling and in which direction by looking at the display on the first display 212 _-1 .

The second display _212-2 shown in Fig. 4(b) is for collectively displaying vehicle surroundings images, driving state information, and currently set mode information for the multiple work vehicles _100-1 to _100-4 . As shown in Fig. 4(b), the second display _212-2 is divided into four screens 411 to 414, and information relating to the multiple work vehicles _100-1 to _100-4 is displayed individually on each of the divided screens 411 to 414. However, in order to display information relating to the multiple work vehicles _100-1 to _100-4 on a single display _212-2 , only a portion of the vehicle surroundings images and driving state information received by the state information receiving unit 24 is displayed.

For example, in the upper left split screen 411, the left half of the split screen 411 displays an image of the surroundings in front of the vehicle captured by the front camera on the left screen _411-1 , and the upper right half of the screen 411-2 displays an image of the surroundings behind the vehicle captured by the rear camera on the right screen _411-2 . Also, the lower right half of the screen _411-3 displays a part of the driving state information and the currently set mode information in a simplified manner. The driving state information displayed here includes, for example, the gear shift, the engine load factor, the remaining fuel, the coolant temperature, the battery voltage, and the like.

As described above, the installation position and installation angle of the front camera that captures the image in front of the work vehicle 100 are adjusted so that the image capture range includes a part of the vehicle body. Also, as shown in FIG. 4B, the housings of the multiple work vehicles _100-1 to _100-4 are provided with identification information (numbers "1 _" to "4" in the example of FIG. 4B) for identifying each of the work vehicles 100-1 to _100-4 within the image capture range of the front camera. The monitoring screen display control unit 25 generates a monitoring screen in a form that includes an image of this identification information, and displays it on the second display _212-2 . This allows the remote operator to intuitively grasp which of the four split screens 411 to 414 displays information relating to which of the multiple work vehicles _100-1 to _100-4 .

The third display _212-3 shown in FIG. 4(c) is for displaying in detail the vehicle surroundings image, status information, and currently set mode information of one work vehicle 100 selected by the vehicle selection switch 331 from among the multiple work vehicles _{100-1 to} 100-4. As shown in FIG. 4(c), the third display _212-3 is divided into seven screens 421 to 427, and the vehicle surroundings images in six directions are displayed on the upper six split screens 421 to 426, respectively. In addition, various status information and currently set mode information are displayed on the horizontally elongated split screen 427 on the lower side. The status information displayed here is part or all of the driving status information and work status information received by the status information receiving unit 24. When only part of the information is displayed, it may be designed as desired which driving status information or work status information is displayed.

In order to reduce the amount of communication between the vehicle control device 10 and the remote control device 20, all of the vehicle surrounding images and status information in all directions may be transmitted from the vehicle control device 10 to the remote control device 20 only for one work vehicle 100 selected by the vehicle selection switch 331, while for the three unselected work vehicles 100, only a portion of the vehicle surrounding images and a portion of the driving status information (including actual steering angle information) to be displayed on the second display _212-2 shown in Figure 4 (b) may be transmitted from the vehicle control device 10 to the remote control device 20.

4(c), the monitoring screen display control unit ₂₅ also generates and displays a monitoring screen in a manner including an image of the identification information of one work vehicle 100 selected by the vehicle selection switch 331. This allows the remote operator to intuitively know which of the multiple work vehicles _100-1 to _100-4 the information displayed on the third display _212-3 relates to.

Furthermore, a message screen 428 for displaying a predetermined message is present on the horizontally elongated split screen 427 on the lower side. When the remotely controlled travel mode is set for the vehicle control device 10 _-i of one work vehicle 100 _-i and an operation is performed to select another work vehicle 100 _-j using the vehicle selection switch 331, the monitoring screen display control unit 25 causes a predetermined warning message to be displayed on the message screen 428. Note that, although an example of displaying a warning message has been described here, a warning sound may also be output from a speaker.

This allows the remote operator to understand that the remotely controlled travel mode cannot be set for the work vehicle 100 _-j selected by the vehicle selection switch 331. In this case, the remote operator can set the autonomous travel mode for one selected work vehicle 100 _-i by using the mode selection switch 332, and then select another work vehicle 100 _-j by using the vehicle selection switch 331 and set the remotely controlled travel mode by using the mode selection switch 332, thereby allowing the one work vehicle 100 _-i to continue traveling while setting the remotely controlled travel mode for the other work vehicle 100 _-j . Note that the one work vehicle 100 _-i may be set to standby mode once, and then changed from standby mode to autonomous travel mode.

As described above, according to this embodiment, the remotely controlled travel mode is not set simultaneously for multiple work vehicles 100, and therefore it is possible to prevent a situation in which a remote operator remotely controls multiple work vehicles 100 simultaneously, while continuing to drive the multiple work vehicles _100-1 to _100-4 , and to set the remotely controlled travel mode for a desired work vehicle 100. As a result, if a situation occurs in which autonomous driving is difficult for a work vehicle 100 _-j that is traveling in autonomous driving mode, it is possible to switch from the autonomous driving mode to the remotely controlled travel mode for that work vehicle 100 _-j , while continuing to drive the multiple work vehicles _100-1 to _100-4 and ensuring safety.

When the mode control unit 22 notifies the work vehicle 100 that it has been switched from another driving mode to the remotely controlled driving mode, the turning curvature difference detection unit 26 detects the difference between the actual turning curvature of the work vehicle 100 that has been switched to the remotely controlled driving mode, which is determined from the actual steering angle information included in the driving state information received by the state information receiving unit 24, and the turning curvature corresponding to the steering angle of the steering wheel 31 of the operation unit 211 at that time.

That is, the turning curvature difference detection unit 26 has information (table information or function information) indicating the correspondence between the steering angle of the actual steering wheel provided on the work vehicle 100 and the turning curvature of the work vehicle 100 for that steering angle, and uses this information to identify the actual turning curvature of the work vehicle 100 from the actual steering angle indicated by the actual steering angle information. The turning curvature difference detection unit 26 also has information (table information or function information) indicating the correspondence between the steering angle of the steering wheel 31 and the turning curvature for that steering angle, and uses this information to identify the turning curvature corresponding to the steering angle of the steering wheel 31 when switched to the remote control travel mode. Then, the difference between the actual turning curvature of the work vehicle 100 identified in this way and the turning curvature corresponding to the steering angle of the steering wheel 31 is detected.

For example, when the driving mode of a work vehicle 100 _-j traveling in an autonomous driving mode is switched to a remotely controlled driving mode, or when the driving mode of a work vehicle 100 _-j traveling in a manual driving mode is switched to the remotely controlled driving mode via a standby mode, the turning curvature corresponding to the steering angle of the work vehicle 100 _-j (the actual steering angle at the time of switching from the autonomous driving mode or the manual operation mode to the remotely controlled driving mode) may not match the turning curvature corresponding to the steering angle of the steering wheel 31 provided in the operation unit 211. The turning curvature difference detection unit 26 detects the difference in turning curvature related to such a mismatch (whether the curvature difference is in the left or right direction, and how large the difference in curvature is).

When the turning curvature difference detection unit 26 detects a turning curvature difference exceeding a predetermined value, the difference control unit 27 controls the remote operation instruction unit 23 to transmit a steering control instruction in a state where the turning curvature difference exceeding the predetermined value is eliminated. Specifically, the difference control unit 27 automatically physically rotates the steering wheel 31 so that the turning curvature corresponding to the steering angle of the steering wheel 31 approaches the actual turning curvature of the work vehicle 100 and the turning curvature difference exceeding the predetermined value is eliminated. At this time, the difference control unit 27 controls the remote operation instruction unit 23 not to transmit a steering control instruction until the rotation of the steering wheel 31 is completed. Here, the predetermined value is a value that can be said to have almost no turning curvature difference, for example, zero or a small value close to it.

Fig. 5 is a diagram showing a schematic example of the operation of the differential control unit 27. Fig. 5 (a1) shows the state of the steering wheel 31 when the travel mode of one work vehicle 100 _-i is switched from the other travel mode to the remotely controlled travel mode. The steering angle of the steering wheel 31 at this time is, for example, when the travel mode of the one work vehicle 100 _-i is switched from the remotely controlled travel mode to the autonomous travel mode or the manual travel mode, and then returned to the remotely controlled travel mode again and the work vehicle 100 _-i operates, and the steering angle is maintained as it is when the remotely controlled travel mode is switched to the autonomous travel mode or the manual travel mode (the remote operator does not operate the steering wheel 31 when the one work vehicle 100 _-i is in the autonomous travel mode or the manual travel mode). Alternatively, the steering angle of the steering wheel 31 shown in FIG. 5 (a1) may be the steering angle when another work vehicle 100 _-j is being remotely controlled when the driving mode of the other work vehicle 100- _j is switched from the remotely controlled driving mode to the other driving mode and the driving mode of one work vehicle 100 _-i is switched from the other driving mode to the remotely controlled driving mode.

Fig. 5(b) shows the actual steering state of one work vehicle 100- _i when the travel mode of the one work vehicle 100 _-i is switched from the other travel mode to the remote control travel mode. As shown in Fig. 5(a1), the steering wheel 31 of the operation unit 211 is rotated to the left. On the other hand, as shown in Fig. 5(b), the actual steering wheel of the one work vehicle 100 _-i is rotated to the right. Therefore, a difference in turning curvature exceeding a predetermined value is detected by the turning curvature difference detection unit 26.

In this case, as shown in Fig. 5 (a2), the difference control unit 27 automatically rotates the steering wheel 31 to the right, thereby bringing the turning curvature corresponding to the steering angle of the steering wheel 31 closer to the actual turning curvature of one of the work vehicles 100 _-i , so that the turning curvature difference exceeding a predetermined value is eliminated. The state in which the turning curvature difference exceeding a predetermined value is eliminated means, for example, a state in which the difference is equal to or less than a predetermined value. Alternatively, it may be a state in which the difference is zero.

5(a2) and 5(b) show a state in which the steering angle of the steering wheel 31 of the remote control device 20 and the actual steering angle of the work vehicle 100 _-i are approximately the same. However, if the left and right rotation angles of the steering wheel 31 and the actual left and right rotation angles of the steering wheel do not match, the steering angle of the steering wheel 31 and the actual steering angle will not necessarily match when the difference in turning curvature that exceeds a predetermined value is eliminated.

In this way, the differential control unit 27 controls the remote operation instruction unit 23 not to transmit a remote operation instruction for steering control to the vehicle control device 10 while the steering wheel 31 is automatically rotated from the state shown in FIG. 5(a1) to the state shown in FIG. 5(a2). In other words, the differential control unit 27 controls the remote operation instruction unit 23 to transmit a remote operation instruction for steering control to the vehicle control device 10 from the time when the rotation of the steering wheel 31 is completed in the state shown in FIG. 5(a2).

Figure 6 is a flowchart showing an example of the operation of the remote operation device 20 of the remote control system configured as described above, and mainly shows an example of the operation when switching the mode of the work vehicle 100 from the other driving mode to the remotely controlled driving mode.

The turning curvature difference detection unit 26 determines whether or not a notification has been received from the mode control unit 22 that any of the work vehicles 100 has been switched from the other driving mode to the remotely controlled driving mode (step S1). If the turning curvature difference detection unit 26 has not received this notification from the mode control unit 22, the remote control device 20 performs processing other than the processing related to this mode switching (step S2). Then, the processing returns to step S1.

On the other hand, when the mode control unit 22 notifies the work vehicle 100 that it has been switched from the other driving mode to the remotely controlled driving mode, the turning curvature difference detection unit 26 determines the actual turning curvature of the work vehicle 100 based on the actual steering angle information contained in the most recent driving state information received by the state information receiving unit 24 for that work vehicle 100, and determines the turning curvature corresponding to the steering angle of the steering wheel 31 of the operation unit 211 at that time, and detects the difference between the two (step S3).

Then, the difference control unit 27 determines whether the difference in turning curvature detected by the turning curvature difference detection unit 26 exceeds a predetermined value (step S4). If the difference in turning curvature exceeds the predetermined value, the difference control unit 27 automatically rotates the steering wheel 31 to bring the turning curvature corresponding to the steering angle of the steering wheel 31 closer to the actual turning curvature of the work vehicle 100, thereby eliminating the difference in turning curvature that exceeds the predetermined value (step S5).

After executing the process of step S5, the process proceeds to step S6. Also, if it is determined in step S4 that the difference in turning curvature does not exceed the predetermined value, the process proceeds to step S6 without executing the process of step S5. In step S6, it is determined whether the power of the remote control device 20 has been turned off. If the power of the remote control device 20 has been turned off, the process of the flowchart shown in FIG. 6 ends. On the other hand, if the power of the remote control device 20 has not been turned off, the process returns to step S1.

While the differential control unit 27 is processing in step S5, the remote operation instruction unit 23 does not transmit a remote operation instruction for steering control to the vehicle control device 10. Then, after the differential control unit 27 has completed processing in step S5, the process proceeds from step S1 to step S2 in response to the operation of the operation unit 211, and the remote operation instruction unit 23 transmits various remote operation instructions, including an instruction for steering control, to the vehicle control device 10.

As described above in detail, in this embodiment, when the driving mode of a certain work vehicle 100 is switched from the other driving mode to the remotely controlled driving mode, the difference between the actual turning curvature of the work vehicle 100 and the turning curvature corresponding to the steering angle of the steering wheel 31 of the remote control device 20 is detected, and if a turning curvature difference exceeding a predetermined value is detected, the steering wheel 31 is automatically rotated so as to eliminate the turning curvature difference exceeding the predetermined value.

According to this embodiment configured as described above, when the other driving mode is switched to the remote controlled driving mode, even if the actual turning curvature of the work vehicle 100 at the time of the switch does not match the turning curvature corresponding to the steering angle of the steering wheel 31, the remote control instruction unit 23 sends a steering control instruction to the vehicle control device 10 in a state where the mismatch is resolved. Therefore, the turning curvature that the remote operator is aware of while operating the steering wheel 31 matches the actual turning curvature of the work vehicle 100, so that the correct steering control can be performed as intended by the remote operator.

In the above embodiment, as an example of the processing of the difference control unit 27 that controls the remote operation instruction unit 23 to transmit a steering control instruction in a state where the difference in turning curvature exceeding a predetermined value is eliminated, the processing of automatically rotating the steering wheel 31 so as to eliminate the difference in turning curvature exceeding a predetermined value is described, but the present invention is not limited to this.

For example, after the turning curvature difference detection unit 26 detects a turning curvature difference exceeding a predetermined value, the difference control unit 27 may not transmit a steering control instruction from the remote operation instruction unit 23 until the difference between the turning curvature corresponding to the steering angle of the steering wheel 31, which varies due to the operation by the remote operator, and the actual turning curvature of the work vehicle 100 no longer exceeds the predetermined value.

For example, when the turning curvature difference detection unit 26 detects a difference in turning curvature exceeding a predetermined value, the monitoring screen display control unit 25 displays a steering image on the split screen 427 of the third display _212-3 in such a manner that the steering angle corresponding to the actual turning curvature of the steering wheel of the work vehicle 100 can be seen. Alternatively, an image may be displayed that allows visual confirmation by comparing the actual turning curvature of the work vehicle 100 with the turning curvature corresponding to the steering angle of the steering wheel 31. The remote operator manually rotates the steering wheel 31 while referring to this image. At this time, the remote operation instruction unit 23, in accordance with the control by the difference control unit 27, does not transmit a steering control instruction to the vehicle control device 10 until the difference between the turning curvature corresponding to the steering angle of the manually operated steering wheel 31 and the actual turning curvature of the work vehicle 100 no longer exceeds the predetermined value.

Here, the remote operator may be notified that the difference between the turning curvature corresponding to the steering angle of the steering wheel 31 and the actual turning curvature of the work vehicle 100 no longer exceeds a predetermined value. The method of notification is arbitrary. For example, when the difference becomes equal to or less than a predetermined value or becomes zero, the steering image displayed on the split screen 427 may be erased. At the same time, a predetermined notification sound may be output.

In the above embodiment, an example has been described in which the steering angle of the work vehicle 100 is used as the steering-related value transmitted by the status information transmission unit 14 of the vehicle control device 10 to the remote control device 20, but the present invention is not limited to this. For example, the turning curvature corresponding to the steering angle of the work vehicle 100 may be transmitted to the remote control device 20 as the steering-related value. In this case, the turning curvature difference detection unit 26 detects the difference between the actual turning curvature of the work vehicle 100 included in the status information received by the status information reception unit 24 and the turning curvature corresponding to the steering angle of the steering wheel 31.

In the above embodiment, an example has been described in which the remote control device 20 transmits the steering amount of the steering wheel 31 or the actual steering amount of the work vehicle 100 converted from the steering amount to the vehicle control device 10 as steering information, but the present invention is not limited to this. For example, the steering amount of the steering wheel 31 may be converted into a turning curvature of the work vehicle 100, and the turning curvature may be transmitted as steering information. In this case, the vehicle control device 10 converts the turning curvature received from the remote control device 20 into an actual steering angle, but it is not necessary for the vehicle control device 10 or the remote control device 20 to convert the steering amount of the steering wheel 31 into an actual steering amount of the work vehicle 100.

In the above embodiment, information indicating the correspondence between the steering angle and the turning curvature may be stored for each type of work vehicle 100 or each type of steering mechanism, so that one remote control device 20 can handle the operation of different types of work vehicles 100 and steering mechanisms. Examples of types of work vehicles 100 include front-wheel steering vehicles such as tractors, four-wheel steering vehicles such as some riding management machines and speed sprayers, articulated vehicles such as wheel loaders (tire shovels), and vehicles that turn using crawler differentials such as combines. The remote control device 20 stores information indicating the correspondence between the turning curvatures identified from the turning angle of the front wheels, the turning angle of all wheels, the bending angle, and the crawler differential and the steering angle of the steering wheel provided for each type of work vehicle, and by selecting and using any of the information, it is possible to control different types of work vehicles 100 with one remote control device 20.

In addition, in the above embodiment, the steering wheel 31 may be configured to match a specific type of work vehicle 100. That is, the remote control device 20 including the steering wheel 31 may be configured to match the left and right rotation angles of the steering wheel of a specific type of work vehicle 100 and the relationship between the steering angle of the steering wheel and the turning curvature of the work vehicle 100. In this way, controlling to eliminate the difference in turning curvature that exceeds a predetermined value is equivalent to controlling to eliminate the difference in steering angle that exceeds a predetermined value, and when the difference is eliminated, the steering angle of the actual steering wheel and the steering angle of the steering wheel 31 of the remote control device 20 match, thereby improving the operating feel.

In addition, the above embodiments are merely examples of how the present invention can be implemented, and the technical scope of the present invention should not be interpreted in a limiting manner. In other words, the present invention can be implemented in various forms without departing from its gist or main features.

REFERENCE SIGNS LIST 10 Vehicle control device 12 Mode setting unit 13 Travel control unit 14 Status information transmission unit 20 Remote control device 22 Mode control unit 23 Remote operation instruction unit 24 Status information reception unit 25 Monitoring screen display control unit 26 Turning curvature difference detection unit 27 Difference control unit 31 Steering wheel 32 Pedal 33 Switch group 34 Gear shift lever 331 Vehicle selection switch 332 Mode selection switch 333 Various switches 334 Emergency switch

Claims (5)

A remote control system for a work vehicle, comprising: a vehicle control device mounted on a work vehicle; and a remote control device located outside the work vehicle, the remote control device including a simulated steering wheel for remote steering control, the remote control device controlling the travel of the work vehicle by instructions given from the remote control device to the vehicle control device,
The vehicle control device includes:
a mode setting unit that sets either a remote control driving mode in which the vehicle is remotely controlled to travel in accordance with a remote control instruction including a steering control instruction received from the remote control device, or another driving mode;
a driving control unit that executes driving control including steering of the work vehicle in accordance with the mode set by the mode setting unit;
a status information transmission unit that sequentially transmits driving status information indicating a driving status including a steering-related value of the work vehicle to the remote control device,
The remote control device is
a remote operation instruction unit that transmits the remote operation instruction to the vehicle control device of the work vehicle in accordance with an operation by a remote operator on an operation unit including the simulated steering;
a status information receiving unit that successively receives the traveling status information transmitted from the status information transmitting unit of the work vehicle;
a turning curvature difference detection unit that detects a difference between an actual turning curvature of the work vehicle identified from the steering-related value included in the traveling state information received by the state information receiving unit when the other traveling mode is switched to the remote control traveling mode, and a turning curvature corresponding to the steering angle of the simulated steering;
A remote control system for a work vehicle, comprising: a difference control unit that controls the remote driving instruction unit to send the steering control instruction in a state where the turning curvature difference exceeding a predetermined value is eliminated when the turning curvature difference detection unit detects a turning curvature difference exceeding a predetermined value. The remote control system according to claim 1, characterized in that, when the turning curvature difference detection unit detects a turning curvature difference exceeding the predetermined value, the difference control unit automatically rotates the simulated steering wheel so that the turning curvature corresponding to the steering angle of the simulated steering wheel approaches the actual turning curvature of the work vehicle to eliminate the turning curvature difference exceeding the predetermined value, and controls the remote operation instruction unit not to transmit the steering control instruction while the simulated steering wheel is being automatically rotated. The remote control system according to claim 1, characterized in that after the turning curvature difference detection unit detects a turning curvature difference exceeding the predetermined value, the difference control unit controls the remote operation instruction unit so as not to transmit the steering control instruction until the difference between the turning curvature corresponding to the steering angle of the simulated steering that varies due to the operation by the remote operator and the actual turning curvature of the work vehicle no longer exceeds the predetermined value. A remote control device that controls travel of a work vehicle by transmitting instructions from outside the work vehicle to a vehicle control device mounted on the work vehicle,
a remote operation instruction unit that transmits a remote operation instruction including an instruction for steering control to the vehicle control device of the work vehicle in accordance with an operation by a remote operator on an operation unit including a simulated steering for remote steering control;
a state information receiving unit that sequentially receives driving state information indicating a driving state including a steering-related value of the work vehicle from the work vehicle;
a mode control unit that controls the setting of the mode by transmitting instructions according to an operation by a remote operator to the vehicle control device having a remote-controlled driving mode in which the vehicle is remotely controlled to drive in accordance with the remote control instructions and another driving mode;
a turning curvature difference detection unit that detects a difference between an actual turning curvature of the work vehicle identified from the steering-related value included in the traveling state information received by the state information receiving unit when the other traveling mode is switched to the remote control traveling mode, and a turning curvature corresponding to the steering angle of the simulated steering;
A remote control device characterized by comprising a difference control unit that controls the remote driving instruction unit to send the steering control instruction in a state where the turning curvature difference exceeding a predetermined value is eliminated when the turning curvature difference detection unit detects a turning curvature difference exceeding a predetermined value. A method for controlling travel of a work vehicle in a remote control system for the work vehicle, the remote control system including a vehicle control device mounted on the work vehicle and a remote control device located outside the work vehicle, the remote control device including a simulated steering for remote steering control, by instructions given from the remote control device to the vehicle control device, comprising:
the vehicle control device has either a remote control driving mode in which the vehicle is remotely controlled to travel in accordance with a remote control instruction including a steering control instruction received from the remote control device, or another driving mode;
a turning curvature difference detection unit of the remote control device detecting a difference between an actual turning curvature of the work vehicle identified from a steering-related value included in driving state information successively received from the vehicle control device when the driving mode of the work vehicle is switched from the other driving mode to the remote controlled driving mode, and a turning curvature corresponding to a steering angle of the simulated steering;
and when the turning curvature difference detection unit detects a turning curvature difference exceeding a predetermined value, a difference control unit of the remote control device controls the remote control device to transmit the steering control instruction in a state where the turning curvature difference exceeding the predetermined value is eliminated.