Work vehicle

Abstract

To provide a work vehicle capable of appropriately determining the end of revolution.SOLUTION: A tractor T comprises: a steering device 5 which steers a traveling machine body 1 using power of an actuator; a camera unit 9 which images the travel direction of the traveling machine body 1; and a steering control unit 10 which automatically controls the steering device 5 on the basis of the photographed image of the camera unit 9. The steering control unit 10 recognizes a work shape line L1 in a previous process on the basis of the photographed image of the camera unit 9, and determines the end of the revolution on the basis of the angular difference θ between the work shape line L1 and a machine body center line L2 during the revolution.SELECTED DRAWING: Figure 6

Description

[Technical field]

[0001] The present invention relates to a work vehicle such as a tractor. [Background technology]

[0002] There have been proposed work vehicles that perform automatic steering. For example, Patent Documents 1 and 2 disclose tractors that are equipped with a camera that captures an image in the traveling direction and automatically control the steering device based on an image captured by the camera. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2020-103084 A [Patent Document 2] JP 2023-66736 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, when a work vehicle such as a tractor travels along multiple roughly parallel paths, it must turn from the end of each path to the start of the next path. This requires various operations (such as lowering the work equipment, restoring engine rotation, and resuming automatic steering) when transitioning from the end of the turn to working travel, which places a heavy burden on the operator. [Means for solving the problem]

[0005] The present invention was created in consideration of the above-mentioned actual situation and with the aim of solving these problems. The invention of claim 1 is a work vehicle comprising a running body that travels along multiple approximately parallel paths and turns from the end position of each path to the start position of the next path, a steering device that steers the running body using the power of an actuator, a camera that photographs the direction of travel of the running body, and a steering control unit that automatically controls the steering device based on the image captured by the camera, wherein the steering control unit comprises a work shape line recognition means that recognizes the work shape line of the previous path based on the image captured by the camera, and a turning end determination means that determines the end of a turn based on the angle difference between the work shape line and the vehicle center line during a turn. The invention of claim 2 is the work vehicle described in claim 1, characterized in that the turning end determination means determines the end of a turn based on the distance traveled during the turn and the steering angle when it is difficult to recognize the work shape line. The invention of claim 3 is the work vehicle described in claim 1, characterized in that when the steering control unit determines that turning has been completed, it automatically performs the control necessary for the next work driving step. The invention of claim 4 is a work vehicle as described in claim 3, wherein the control required for the work traveling of the next stroke includes a previous stroke following control that automatically controls the steering device so that the traveling body travels for work along the work shape line of the previous stroke, and when the steering control unit determines that turning has ended, it executes a following interpolation control that returns the traveling body to a straight-ahead state, and then executes the previous stroke following control. The invention of claim 5 is a work vehicle as described in claim 4, characterized in that the following interpolation control causes the running body to move straight along the work shape line of the previous stroke, and when it is difficult to recognize the work shape line, causes the running body to move straight based on the distant view captured by the camera. Effect of the Invention

[0006] According to the invention of claim 1, the steering control unit recognizes the working shape line of the previous process based on the image captured by the camera, and determines the end of the turn based on the angle difference between the working shape line and the aircraft center line during the turn, so that the operation required at the end of the turn can be automated and the operational burden of the operator can be reduced. As a result, it is possible to prevent a decrease in work efficiency due to an increase in the operational burden of the operator. Furthermore, according to the invention of claim 2, when it is difficult to recognize the working shape line, the end of turning is determined based on the travel distance and steering angle during turning, so that the end of turning can be appropriately determined in various situations. In addition, according to the invention of claim 3, when the steering control unit determines that turning has been completed, it automatically executes the control required for the next work driving stage, thereby not only eliminating the need to perform operations to execute the control, but also preventing a decrease in work accuracy due to forgetting to perform operations. In addition, according to the invention of claim 4, following interpolation control is executed to return the traveling body to a straight-line state upon completion of turning, and then pre-stroke following control is executed. This makes it possible to smoothly transition from turning traveling to work traveling compared to the case where pre-stroke following control is executed immediately after completion of turning. In addition, according to the invention of claim 5, the following interpolation control causes the running body to move straight along the work shape line of the previous process, and when it is difficult to recognize the work shape line, causes the running body to move straight based on the distant view captured by the camera, thereby enabling a smooth transition from turning running to work running in a variety of situations. [Brief description of the drawings]

[0007] [Figure 1] FIG. [Diagram 2] FIG. 2 is a perspective view showing the shooting posture of the camera unit. [Diagram 3] FIG. 4 is a perspective view showing a stored position of the camera unit. [Figure 4] FIG. 4 is a front view showing the operation panel of the driving section. [Diagram 5] 4 is a block diagram showing inputs and outputs of a steering control unit and a work control unit. FIG. [Figure 6]1A and 1B are diagrams illustrating the principle of turning end determination. [Figure 7] 4 is a flowchart showing a processing procedure of automatic steering control. [Figure 8] 11 is a flowchart showing the processing procedure of machine information acquisition 1. [Figure 9] 13 is a flowchart showing the procedure of a machine information acquisition 2 process. [Figure 10] 11 is a flowchart showing the procedure of a follow-up interpolation 1 process. [Figure 11] 13 is a flowchart showing the procedure of a follow-up interpolation 2 process. [Figure 12] 13 is a flowchart showing a processing procedure of follow-up control. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In Fig. 1, reference numeral 1 denotes a traveling machine body of a tractor T (work vehicle), and a working machine S (see Fig. 6) is connected to the rear of the traveling machine body 1 via a lifting link mechanism (not shown) so that the working machine S can be raised and lowered. Various working machines S can be connected to the traveling machine body 1, but in this embodiment, it is assumed that a ridge-making working machine S that cultivates a field and forms ridges is connected to the traveling machine body 1.

[0009] The running body 1 comprises an engine mounting section 2 on which an engine (not shown) is mounted, a transmission case 3 which changes the engine power to output running power and working power, left and right front wheels 6 which are steered in accordance with manual operation of a steering handle 4 or operation of a steering device 5 (see Figure 5) and are rotated and driven by the running power output from the transmission case 3, left and right rear wheels 7 which are rotated and driven by the running power output from the transmission case 3, and a driving section 8 on which various operating tools such as the steering handle 4 are arranged.

[0010] As shown in Figs. 1 to 3, a camera unit 9 (camera) that photographs the traveling direction (forward direction) of the traveling machine body 1 is provided near the front of the driving unit 8. The camera unit 9 is configured to be able to change its posture between a photographing posture that stands up near the front of the driving unit 8 and photographs the traveling direction of the traveling machine body 1, as shown in Figs. 1 and 2, and a stored posture in which it lies down forward with its lower end portion as a pivot point, as shown in Fig. 3. This allows the camera unit 9 to be in the stored posture during non-work driving, such as driving on the road, to expand the forward field of view.

[0011] The camera unit 9 is connected to a steering control unit 10 (see FIG. 5) described later, and transmits the captured images to the steering control unit 10. The camera unit 9 is also provided with a communication unit 9a that performs wireless communication, and can transmit the captured images to a mobile terminal 11 or the like. This makes it possible to monitor the images captured by the camera unit 9 inside or outside the vehicle.

[0012] 1 and 4, the driving unit 8 includes an operation panel 12. The operation panel 12 includes the steering wheel 4 described above, a meter panel 13 for displaying engine rpm and the like, a key switch 14 for turning the main power on and off and starting and stopping the engine, an accelerator lever 15 for setting the engine rpm, a forward / reverse switch lever 16 for switching between forward and reverse travel, a turn signal lever 17 for turning on and off the direction indicators, a quick lever 18 for raising and lowering the work machine S, and a mode select operation device 19 for selecting and deciding on the display unit.

[0013] Also, a steering device 5 that steers the traveling machine body 1 (front wheels 6) with the power of an actuator is built into the operation panel 12. As shown in Fig. 5, the steering device 5 is disposed in a steering column 20, and includes a steering drive motor 22 (actuator) that rotates a steering shaft 21, a steering angle sensor 23 that detects the steering angle of the front wheels 6, a steering setting unit 24 that sets the automatic steering control, a steering display unit 25 that displays information related to the automatic steering control, and a steering control unit 10 that executes the automatic steering control.

[0014] The automatic steering control is a control that automatically steers the traveling body 1 (front wheels 6) based on the image captured by the camera unit 9, and includes control modes such as a distant view straight ahead mode, a V-groove following mode, a previous journey following mode, and a ridge following mode.

[0015] The straight-ahead distant view mode is a mode in which a reference point in the distance and the start position of the journey are recognized in the image captured by the camera unit 9, and the steering drive motor 22 is controlled so that the vehicle travels for work along a straight-ahead reference line connecting the reference point in the distance and the start position of the journey.

[0016] The V-groove following mode is a mode in which the steering drive motor 22 is controlled so that the robot travels for work along a V-groove (not shown) formed by a marker (not shown) in a previous process. For example, in the V-groove following mode, the steering drive motor 22 is controlled so that the robot travels for work while recognizing the V-groove in an image captured by the camera unit 9 and maintaining a state in which the V-groove is positioned in the left-right center of the traveling machine body 1.

[0017] The previous stroke following mode is a mode in which work traces from the previous stroke (steps such as ridge making marks) are recognized in images captured by the camera unit 9, and the steering drive motor 22 is controlled so that the vehicle travels along the work traces from the previous stroke.

[0018] The ridge following mode is a mode in which the ridges of the field (steps on the periphery of the field) are recognized in the images captured by the camera unit 9, and the steering drive motor 22 is controlled so that the vehicle travels along the ridges during work.

[0019] 4, the steering setting unit 24 includes a steering power switch 26 that turns the main power supply of the steering device 5 ON / OFF, an automatic steering mode changeover dial 27 that switches the control mode of the automatic steering control, and steering amount switches 28-30 that set the steering amount (control sensitivity) in the automatic steering control. In addition, the steering display unit 25 includes a power lamp 31 that displays the ON / OFF state of the main power supply, recognition lamps 32 and 33 that display the recognition state (detection state) of the V groove, work marks of the previous process, ridges, etc., and steering amount lamps 34-36 that display the selected steering amount (control sensitivity).

[0020] As shown in Fig. 5, the traveling machine body 1 is provided with a work control unit 40. An input device such as a travel distance sensor 41 (axle rotation sensor) that detects the travel distance of the traveling machine body 1 is connected to the input side of the work control unit 40, and various controlled devices are connected to the output side of the control unit 40. For example, the controlled devices include a double speed switching valve 42 that rotates the front wheels 6 at double speed when turning, an auto brake switching valve 43 that brakes the rear wheel 7 on the inside of the turn when turning, a work machine lift valve 44 that lifts and lowers the work machine S, a horn 45 that issues an alarm by sound, and a lamp 46 that issues an alarm by light.

[0021] The steering control unit 10 is communicatively connected to the work control unit 40 via a CAN or the like. This enables the steering control unit 10 to acquire machine information such as mileage from the work control unit 40 and indirectly control devices that are the control targets of the work control unit 40.

[0022] The steering control unit 10 includes a working shape line recognition means and a turning end determination means as functional configurations realized by cooperation between hardware and software.

[0023] The work shape line recognition means recognizes the work shape line of the previous stroke based on the image captured by the camera unit 9. For example, as shown in Fig. 6, when the machine travels for ridge-making work along multiple substantially parallel strokes and turns from the end position of each stroke to the start position of the next stroke, the work shape line recognition means detects the ridges (step portions) of the previous stroke based on pattern matching processing or shape matching rate processing in the image captured by the camera unit 9, and recognizes the work shape line L1 of the previous stroke by linearly approximating multiple ridge detection points P.

[0024] In the pattern matching process, the image captured by the camera unit 9 is compared with a reference image (e.g., an image of a ridge step portion) and image positions with a high matching rate are extracted as pattern match detection points. Then, the work shape line L1 of the previous process (e.g., a ridge step portion line) is specified by linearly approximating the multiple pattern match detection points.

[0025] In the shape matching process, the ground shape is calculated from images captured at different times, the matching rate between the calculated ground shape and the reference ground shape pattern is calculated, and image positions with a high matching rate are extracted as shape matching points. Then, the work shape line L1 (e.g., ridge step line) of the previous process is specified by linear approximation of multiple shape matching points.

[0026] The turning end determination means determines the end of turning based on the angle difference θ between the work shape line L1 of the previous stroke and the vehicle center line L2 during turning. For example, when the angle difference θ becomes equal to or smaller than a threshold value θ1, it determines that turning has ended. This automates the operations required at the end of turning, reducing the burden on the operator.

[0027] Furthermore, when it is difficult to recognize the work shape line L1 of the previous process, the turning end determination means determines the end of the turn based on the travel distance during the turn and the steering angle. This allows the end of the turn to be appropriately determined in various situations. Note that, as a situation in which it is difficult to recognize the work shape line L1 of the previous process, it is assumed that the work start time when the previous process does not exist, the image captured by the camera unit 9 is distorted, etc.

[0028] When the steering control unit 10 determines that the turning has ended, it is desirable to automatically execute control necessary for the work traveling of the next process. Examples of controls necessary for the work traveling of the next process include automatic work machine lowering control for lowering the work machine S, automatic marker lowering control for lowering the marker, automatic engine speed return control for returning the engine speed to the work speed, and previous process following control for automatically steering the traveling machine body 1 along the work shape line L1 of the previous process (previous process following mode of automatic steering control: equivalent to the following control in FIG. 12). In this way, not only can the operation for executing the control be omitted, but also a decrease in work accuracy due to forgetting to operate can be prevented.

[0029] Furthermore, when the steering control unit 10 executes the front stroke following control after the turning is completed, it is desirable to execute the front stroke following control after executing the following interpolation control (corresponding to the following interpolation 1 in FIG. 10 and the following interpolation 2 in FIG. 11) that returns the traveling machine body 1 to a straight traveling state. In this way, the transition from turning traveling to working traveling can be made smoother than when the front stroke following control is executed immediately after the turning is completed.

[0030] The following interpolation control moves the traveling body 1 straight along the work shape line L1 of the previous process (corresponding to following interpolation 1 in FIG. 10), but when it is difficult to recognize the work shape line L1, the traveling body 1 is moved straight based on the distant view captured by the camera unit 9 (corresponding to following interpolation 2 in FIG. 11). This allows for a smooth transition from turning travel to work travel in various situations.

[0031] Next, the specific processing procedure of the steering control unit 10 that realizes the above-mentioned functional configuration will be described with reference to Fig. 7 to Fig. 12. However, it is assumed that the previous stroke following mode is selected on the automatic steering mode switching dial 27. Also, the flowchart shown in Fig. 7 is for explaining the processing procedure when switching from turning driving to working driving, and the processing procedure when switching from working driving to turning driving is omitted.

[0032] 7, the steering control unit 10 judges whether or not the image captured by the camera unit 9 is in an error state (S101), and if the result of this judgment is NO, the automatic steering is stopped. On the other hand, if the steering control unit 10 judges that the image captured by the camera unit 9 is not in an error state (S101: YES), it judges whether or not turning is in progress (S102), and if the result of this judgment is NO, it executes the processing for work driving described later (S115 to S118).

[0033] When the steering control unit 10 determines that the vehicle is turning (S102: YES), it determines whether the captured image from the previous stroke is usable or not (S103), and if the result of this determination is YES, it executes processing for the second stroke and thereafter (S111 to S114) described later.

[0034] When the steering control unit 10 determines that the captured image of the previous stroke cannot be used (S103: NO), it determines the end of the turn in the subroutine, aircraft information acquisition 1 (see FIG. 8) (S104). When the steering control unit 10 determines that the turn has ended, it performs the above-mentioned ridge detection by pattern matching (detects the ridge step portion of the previous stroke) (S105), and creates a following reference line from multiple pattern match detection points (S106). Thereafter, the steering control unit 10 judges whether or not it was possible to detect a predetermined number or more (for example, 3 or more) of ridges (S107), and if the result of this judgment is NO, it executes the processing (S112 to S114) described below, but if the result of the judgment is YES, it notifies the start of follow-up interpolation control (S108), executes the subroutine follow-up interpolation 1 (see Figure 10) (S109), and then notifies the start of follow-up control (S110), and proceeds to processing for work driving (S115 to S118).

[0035] When the steering control unit 10 determines that there is a captured image of the previous process (S103: YES), it determines the end of turning in the vehicle information acquisition 2 subroutine (see FIG. 9) (S111). When the steering control unit 10 determines that the turning has ended, it notifies the start of the follow-up interpolation control (S112), executes the follow-up interpolation 2 subroutine (see FIG. 11) (S113), and then determines whether an error has occurred in the follow-up interpolation 2 (S114). When the result of this determination is NO, it notifies the start of the follow-up control (S110) and proceeds to the work driving process (S115 to S118), but when it determines that an error has occurred, it stops the automatic steering.

[0036] When the steering control unit 10 shifts to the process for traveling for work, it calculates the ground shape (S115), calculates the coincidence rate with the shape pattern (S116), and then performs a tracking control subroutine (see FIG. 12). In addition, the steering control unit 10 records the ridge image, ridge direction, and travel interval during traveling for work (S118).

[0037] In aircraft information acquisition 1 shown in Fig. 8, the steering control unit 10 calculates the current position from the steering angle and the travel distance (S201), and judges whether or not a 180° turn has been completed (S202). If the judgment result of step S202 is NO, the steering control unit 10 repeats steps S201 and S202 while notifying that a turn is being made (S203), and if the judgment result of step S202 is YES, returns to the upper routine shown in Fig. 7.

[0038] In machine body information acquisition 2 shown in Fig. 9, the steering control unit 10 loads the ridge direction of the previous stroke (S301), sets the opposite direction to the previous ridge direction as the detection range (S302), and performs ridge detection by pattern matching (S303). The steering control unit 10 repeats step S303 until the number of ridge detection points reaches three or more (S304: NO), and when the number of ridge detection points reaches three or more (S304: YES), the steering control unit 10 linearly approximates the detection points to identify the work shape line L1 of the previous stroke (S305), and then determines whether the angle difference θ between the work shape line L1 of the previous stroke and the machine body center line L2 is equal to or less than the threshold value θ1 (S306). If the determination result in step S306 is NO, the steering control unit 10 repeats steps S303 to S306 while notifying that a turn is being made (S307), and if the determination result in step S306 is YES, it determines that the turn has ended and returns to the upper routine shown in FIG. 7.

[0039] In the following interpolation 1 shown in FIG. 10, the steering control unit 10 loads the travel interval recorded in the previous travel (S401), creates a following reference line from the pattern match detection point (S402), and executes the steering control subroutine (S403). As a result, the traveling vehicle body 1 is automatically steered so as to travel along the following reference line. When executing the steering control, the steering control unit 10 judges whether or not the following control is possible, that is, whether or not the vehicle has returned to a straight line (S404). If the judgment result is NO, steps S402 to S404 are repeated, and if the judgment result is YES, the process returns to the upper routine shown in FIG. 7. The following reference line in step S402 may be created based on a predetermined algorithm or may be created using a machine learning model.

[0040] In the following interpolation 2 shown in Fig. 11, the steering control unit 10 temporarily switches the control mode to the distant view straight-line mode (S501), and then judges whether the distant view object acquisition process is completed (S502), and if the judgment result is YES, executes the steering control, which is a subroutine (S503). As a result, the traveling machine body 1 is automatically steered so as to travel straight with the distant view object as a reference. When executing the steering control, the steering control unit 10 judges whether the following control is possible, that is, whether the vehicle has returned to straight-line travel (S504), and if the judgment result is NO, the steering control is repeated, and if the judgment result is YES, the process returns to the upper routine shown in Fig. 7.

[0041] In addition, if the judgment result of step S502 is NO, the steering control unit 10 maintains the steering angle at 0° (S505) and judges whether the distance traveled without completing distant object acquisition has reached a predetermined distance (S506). If the judgment result is NO, steps S502, S505 and S506 are repeated. If the judgment result becomes YES, error processing is executed (S507) and then the process returns to the upper routine shown in FIG. 7.

[0042] In the tracking control shown in Fig. 12, the steering control unit 10 performs ridge detection by pattern matching (S601), creates a tracking reference line from the shape matching points and the pattern matching detection points (S602), and then executes steering control, which is a subroutine (S603). As a result, the traveling machine body 1 is automatically steered so as to travel along the tracking reference line created from the shape matching points and the pattern matching detection points. Note that the creation of the tracking reference line in step S602 may be based on a predetermined algorithm, or may be created using a machine learning model.

[0043] According to this embodiment configured as described above, the tractor T is equipped with a running body 1 that travels along multiple approximately parallel paths and turns from the end position of each path to the start position of the next path, a steering device 5 that steers the running body 1 using the power of an actuator, a camera unit 9 that photographs the direction of travel of the running body 1, and a steering control unit 10 that automatically controls the steering device 5 based on the image captured by the camera unit 9.The steering control unit 10 is equipped with a work shape line recognition means that recognizes the work shape line L1 of the previous path based on the image captured by the camera unit 9, and a turning end determination means that determines the end of a turn based on the angle difference θ between the work shape line L1 and the body center line L2 during a turn, so that the operations required at the end of a turn can be automated, reducing the operational burden on the operator.

[0044] Furthermore, when it is difficult to recognize the working shape line L1, the turning end determination means determines the end of the turn based on the travel distance and steering angle during the turn, so that the end of the turn can be appropriately determined in various situations.

[0045] In addition, when the steering control unit 10 determines that turning has been completed, it automatically executes the control required for the next work driving stage, thereby not only eliminating the need to perform operations to execute the control, but also preventing a decrease in work accuracy due to forgetting to perform operations.

[0046] In addition, the control required for the next stroke of work driving includes previous stroke following control, which automatically controls the steering device 5 so that the running body 1 performs work driving along the work shape line L1 of the previous stroke, and when the steering control unit 10 determines that the turning has been completed, it performs following interpolation control to return the running body 1 to a straight-line state, and then performs previous stroke following control, so that the transition from turning driving to work driving can be made smoother than when previous stroke following control is performed immediately after the turning has been completed.

[0047] In addition, the following interpolation control moves the running body 1 straight along the work shape line L1 of the previous process, and when it is difficult to recognize the work shape line L1, it moves the running body 1 straight based on the distant view captured by the camera unit 9, so that a smooth transition from turning driving to work driving can be made in a variety of situations.

[0048] Of course, the present invention is not limited to the above embodiment. For example, in the above embodiment, the process for transition from work travel to turning travel is omitted, but the end position of the process may be detected and the process for automatic turning to the next process may be executed. During automatic turning, it is preferable to execute the raising control of the working implement S, the raising control of the marker, the engine speed reduction control, etc. In addition, the direction of automatic turning may be set in advance, may be reversed left and right for each turn, or may be the opposite direction to the ridge detected in the previous process. In addition, in the above embodiment, when the work shape of the previous process cannot be recognized, the end of turning is determined based on the travel distance and the steering angle, but the end of turning may be determined based on the positional relationship with the sign by setting a sign in the field. [Explanation of symbols]

[0049] T Tractor 1 Running body 5 Steering Gear 9 Camera unit (camera) 10 Steering control unit 22 Steering drive motor (actuator)

Claims

1. A traveling machine body that travels for work along a plurality of substantially parallel strokes and turns from the end position of each stroke to the start position of the next stroke; A steering device that steers the traveling machine body using the power of an actuator; A camera that photographs the traveling direction of the traveling machine body; A steering control unit that automatically controls the steering device based on an image captured by the camera, The steering control unit includes: a work shape line recognition means for recognizing a work shape line of a previous process based on an image captured by the camera; and a turning end determination means for determining the end of a turn based on an angle difference between the work shape line and a vehicle center line during a turn.

2. 2. The work vehicle according to claim 1, wherein the turning end determination means determines the end of a turn based on a travel distance and a steering angle during a turn when it is difficult to recognize the work shape line.

3. 2. The work vehicle according to claim 1, wherein the steering control unit automatically executes control required for a next work travel step when it is determined that the turning has ended.

4. The control necessary for the work traveling of the next stroke includes a previous stroke following control that automatically controls the steering device so that the traveling machine body travels for work along the work shape line of the previous stroke, The work vehicle according to claim 3, characterized in that, when it is determined that turning has ended, the steering control unit executes a follow-up interpolation control to return the traveling body to a straight-ahead state, and then executes the pre-stroke follow-up control.

5. The tracking interpolation control includes: The traveling machine body is moved straight along the work shape line of the previous stroke, 5. The work vehicle according to claim 4, wherein when it is difficult to recognize the work shape line, the traveling body is caused to move straight based on the distant view captured by the camera.

Images