Work vehicles

Abstract

To provide a work vehicle having improved workability even in a deformed field.SOLUTION: A work vehicle is configured to acquire a difference in positions in a prescribed direction between a predicted turning start position and a turning start position on a first virtual target travel line as a correction value in an automatic mode when the work vehicle travels on a first virtual target travel line, a second virtual target travel line, and a third virtual target travel line that are arranged next to each other in order, and to calculate a predicted turning start position on the third virtual target travel line by adding the correction value to coordinates in the prescribed direction of the turning start position of the first virtual target travel line or a turning end position of the second virtual target travel line.SELECTED DRAWING: Figure 10

Description

[Technical Field]

[0001] The present invention relates to a work vehicle that can be automatically steered so as to travel straight in a field, and particularly to a control device that is suitable for application to a rice transplanter. [Background technology]

[0002] Conventionally, a riding rice transplanter is known that automatically steers the traveling machine body so that it moves straight along a preset travel line (see Patent Document 1). In this riding rice transplanter, by manually operating an operation button, it is possible to switch between a stopped state in which automatic steering is not performed and an operating state in which automatic steering is performed, and the operating state is switched from the stopped state when the machine body starts to turn on the headland, and from the stopped state to the operating state after the machine body has finished turning. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2017-134471 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the riding rice transplanter described in Patent Document 1, the automatic steering is switched between a stopped state and an active state by operating an operation button, which makes operation cumbersome and poses problems in terms of workability, especially in irregularly shaped fields that are not rectangular.

[0005] SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a work vehicle that has improved workability even in irregularly shaped fields. [Means for solving the problem]

[0006] The present invention relates to a work vehicle that includes a traveling machine body supported by a traveling device, a positioning system that detects positioning data of the work vehicle, and a control unit that can perform automatic steering to automatically steer the traveling machine body based on the positioning data detected by the positioning system so that the work vehicle travels straight in a predetermined direction along a plurality of virtual target traveling lines that are parallel to each other and that are calculated in advance. the control unit has an automatic mode in which, at an automatic steering stop position determined based on a turning start predicted position, the control unit automatically transitions from an automatic steering ON state in which the automatic steering is performed to an automatic steering OFF state in which the automatic steering is not performed, and automatically transitions from the automatic steering OFF state to the automatic steering ON state at a turning end position whose coordinate in the predetermined direction is the same as a turning start position at which a turning operation for moving to the adjacent virtual target driving line is started, When the work vehicle travels on a first virtual target driving line, a second virtual target driving line, and a third virtual target driving line that are adjacent to each other and arranged in order among the multiple virtual target driving lines, in the automatic mode, a difference in position in the predetermined direction between the predicted turning start position on the first virtual target driving line and the turning start position is obtained as a correction value, and the predicted turning start position on the third virtual target driving line is calculated by adding the correction value to the coordinate in the predetermined direction of the turning start position on the first virtual target driving line or the turning end position on the second virtual target driving line. The present invention relates to a work vehicle characterized by the above.

[0007] The present invention also provides a work vehicle including a traveling machine body supported by a traveling device, a positioning system that detects positioning data of the work vehicle, and a control unit that can perform automatic steering to automatically steer the traveling machine body based on the positioning data detected by the positioning system so that the work vehicle travels straight in a predetermined direction along a plurality of virtual target traveling lines that are parallel to each other and that are calculated in advance, the control unit has an automatic mode in which, at an automatic steering stop position determined based on a turning start predicted position, the control unit automatically transitions from an automatic steering ON state in which the automatic steering is performed to an automatic steering OFF state in which the automatic steering is not performed, and automatically transitions from the automatic steering OFF state to the automatic steering ON state at a turning end position whose coordinate in the predetermined direction is the same as a turning start position at which a turning operation for moving to the adjacent virtual target driving line is started, When the work vehicle travels on a first virtual target driving line, a second virtual target driving line, and a third virtual target driving line that are adjacent to each other and arranged in order among the multiple virtual target driving lines, in the automatic mode, a difference in position in the predetermined direction between the predicted turning start position on the first virtual target driving line and the turning end position on the second virtual target driving line is obtained as a correction value, and the predicted turning start position on the third virtual target driving line is calculated by adding the correction value to the coordinate in the predetermined direction of the turning start position on the first virtual target driving line or the turning end position on the second virtual target driving line. The present invention relates to a work vehicle characterized by the above. [Effects of the Invention]

[0008] According to the present invention, the difference between the predicted turning start position and the turning start position or the turning end position is calculated as a correction value, and the predicted turning start position to be set on the virtual target driving line thereafter is calculated using the correction value. This makes it possible to switch to the automatic steering off state at an appropriate automatic steering position even in a non-rectangular, irregularly shaped field, thereby improving workability. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a side view showing a riding rice transplanter according to a first embodiment. [Figure 2] FIG. [Figure 3] FIG. 2A is a perspective view showing the steering wheel and the automatic steering unit, and FIG. 2B is a front view showing the operation panel. [Figure 4]FIG. 2 is a block diagram showing a control configuration for performing automatic steering control. [Figure 5] FIG. 10 is a diagram for explaining teaching travel control and automatic steering control in manual mode in a square field. [Figure 6] 10 is a flowchart showing teaching travel control. [Figure 7] 4 is a flowchart showing automatic steering control in manual mode. [Figure 8] 4 is a flowchart showing automatic steering restriction control. [Figure 9] 10 is a flowchart showing automatic steering restriction control according to a modified example. [Figure 10] 10A and 10B are diagrams for explaining teaching travel control and automatic steering control in automatic mode in a deformed field. [Figure 11] 4 is a flowchart showing automatic steering control in automatic mode. [Figure 12] 10 is a flowchart showing automatic steering control in an automatic mode according to a second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0010] First Embodiment A first embodiment of the present invention will be described below with reference to the drawings. In Figures 1 and 2, a riding rice transplanter P as a work vehicle includes a traveling body 1 supported by front wheels 9 and rear wheels 10, and a planting implement 3 connected to the rear of the traveling body 1 via a lifting link mechanism 2 so that it can be raised and lowered.

[0011] The planting machine 3 comprises a seedling carrier 4 on which mat seedlings are placed, and a planting mechanism 5 that scrapes the seedlings from the bottom end of the seedling carrier 4 and plants them in the field. The planting machine 3 of this embodiment is an eight-row planting model that can plant eight rows of seedlings at the same time, and eight planting mechanisms 5 are arranged side by side at predetermined intervals in the vehicle width direction.

[0012] The traveling vehicle 1 comprises an engine mounting section 6 on which an engine (not shown) is mounted, a transmission case 7 that changes the engine power and outputs it as traveling power and working power, and a control section 11 on which an operator rides. Front wheels 9 are driven by the traveling power output from the transmission case 7 and are steered in response to operation of a steering handle 8, while rear wheels 10 are driven by the traveling power output from the transmission case 7. The front wheels 9 and rear wheels 10 form a traveling device, and these front wheels 9 and rear wheels 10 may be composed of crawlers or the like. The traveling vehicle 1 also comprises a pair of left and right marker devices 12 that draw a target traveling line for the next journey, but as these are not used in this embodiment, detailed description thereof will be omitted.

[0013] The control unit 11 includes a driver's seat 13 where the operator sits, the aforementioned steering handle 8 located in front of the driver's seat 13, a main speed change lever 14 for changing the speed of the traveling power and the working power, a sub-speed change lever (not shown) for switching the speed range of the main speed change lever 14, and a work machine lifting lever (not shown) that also serves as a lifting / lowering operation device for the planting work machine 3 and a planting clutch operation device.

[0014] As shown in Figure 3(a), an automatic steering unit 15 is connected to the steering wheel 8. The automatic steering unit 15 includes a steering motor 16 (see Figure 4) that rotates the steering wheel 8 using motor power instead of manual operation of the steering wheel 8, and an operation panel 17 on which operating tools and monitor lamps related to automatic steering control, which will be described later, are arranged. Note that manual operation of the steering wheel 8 is permitted even while the steering motor 16 is being driven.

[0015] As shown in FIG. 3(b), the operation panel 17 is equipped with a power switch 18, an automatic steering switch 19, a start point A registration switch 20 for registering a start point A (described later), an end point B registration switch 21 for registering an end point B, and a notification display unit 22 for providing notifications by lamp display. When pressed, the automatic steering switch 19 as an operation unit can switch the automatic steering control (described later) between an automatic steering off state in which automatic steering is not performed, and an automatic steering on state in which automatic steering is performed. More specifically, in the automatic steering off state, automatic steering by the automatic steering control is not performed, and therefore driving of the steering motor 16 is restricted. On the other hand, in the automatic steering on state, automatic steering by the automatic steering control is performed, and driving of the steering motor 16 is permitted.

[0016] The notification display unit 22 is equipped with an excess speed notification lamp 23 that notifies of excessive speeding, a speed-up OK notification lamp 24 that notifies of a state in which speeding up is possible, and a target line notification lamp 50 that indicates that the traveling vehicle 1 is located on the target traveling line. Furthermore, the operation panel 17 is provided with an automatic steering mode changeover switch 51 that can switch the automatic steering control described below between automatic mode and manual mode, and arranged near the automatic steering mode changeover switch 51 are a manual mode notification lamp 52 that indicates that manual mode has been selected, and an automatic mode notification lamp 53 that indicates that automatic mode has been selected.

[0017] A positioning frame 25, which is U-shaped when viewed from the front, is erected on the control unit 11. The positioning frame 25 has a pair of left and right vertical frame sections 25a extending upward and a horizontal frame section 25b connecting the upper ends of the left and right vertical frame sections 25a. Two GNSS antennas 27, 28, which are components of a positioning system 26 (described below), are attached to the horizontal frame section 25b, and a tablet 29 that displays navigation information is attached to one of the left and right vertical frame sections 25a.

[0018] As shown in FIG. 4, the traveling vehicle 1 includes a positioning system 26 and a control unit 30 as a control configuration for performing automatic steering control. The positioning system 26 may be, for example, an RTK-GNSS positioning system capable of highly accurate positioning with an error of a few centimeters. The RTK-GNSS positioning system performs GNSS positioning, such as GPS, at both a fixed base station and a moving mobile station, and corrects the positioning data in real time using a correction signal transmitted from the base station to the mobile station, thereby achieving highly accurate positioning with an error of a few centimeters. Furthermore, by installing two GNSS antennas at a predetermined distance on the mobile station, it becomes possible to detect not only the absolute position of the mobile station but also the direction of travel (azimuth) of the mobile station with high accuracy based on the two positioning results.

[0019] 4, the positioning system 26 of this embodiment includes a GNSS unit 31 which is a control unit that performs RTK-GNSS positioning, a reference GNSS antenna 27 and a direction GNSS antenna 28 which are attached to the lateral frame portion 25b of the positioning frame 25 at a predetermined interval in the vehicle width direction, a gyro sensor 54, and a correction signal receiving device 33 that receives a correction signal from a fixedly installed RTK base station 32. The GNSS unit 31 transmits positioning data (absolute position data and traveling direction data) obtained by RTK-GNSS positioning to the control unit 30 via wired communication means such as CAN, and also transmits it to the tablet 29 via wireless communication means such as Bluetooth (registered trademark).

[0020] The control unit 30 is a control unit that executes automatic steering control, and connected to the input side of the control unit 30 are the above-mentioned automatic steering switch 19, start point A registration switch 20, end point B registration switch 21, and automatic steering mode selector switch 51, as well as a main speed change lever sensor 35 that detects the operating position of the main speed change lever 14, an auxiliary speed change lever sensor 36 that detects the operating position of the auxiliary speed change lever, a steering angle sensor 37 that detects the steering angle of the front wheels 9, a vehicle speed sensor 38 that detects the vehicle speed of the traveling machine body 1, and a rotation sensor 39 that detects the rotation of the axle (travel distance). Connected to the output side of the control unit 30 are the above-mentioned steering motor 16, notification display unit 22, and various lamps (not shown), as well as an alarm buzzer 40 that outputs alarm sounds.

[0021] The automatic steering control is an automatic control function that automatically steers the traveling vehicle 1 so that it travels straight along a virtual target traveling line calculated in advance or a target traveling line drawn in the field. In this embodiment, the traveling vehicle 1 is automatically steered so that it travels straight along a virtual target traveling line calculated in advance, without drawing a target traveling line in the field.

[0022] The automatic steering control in this embodiment has an automatic mode and a manual mode that can be selectively switched by the automatic steering mode selector switch 51. In the manual mode, the automatic steering switch 19 switches between the automatic steering OFF state and the automatic steering ON state. That is, after traveling straight along the virtual target driving line using the automatic steering control, the operator presses the automatic steering switch 19 when turning toward an adjacent row or before turning, thereby switching from the automatic steering ON state to the automatic steering OFF state and temporarily suspending the automatic steering (straight-line assist). This cancels the assistance of the steering wheel 8 by the steering motor 16. Then, after completing the turning operation toward the adjacent row, the operator presses the automatic steering switch 19 again to switch from the automatic steering OFF state to the automatic steering ON state and resume automatic steering (straight-line assist). This resumes the assistance of the steering wheel 8 by the steering motor 16.

[0023] As will be described later, in automatic mode, the control unit 30 calculates a predicted turn start position, and at a position a distance D2 before the predicted turn start position, the automatic steering is switched from the ON state to the OFF state without operating the automatic steering switch 19. Furthermore, at a turn end position calculated based on the turn start position, the automatic steering is switched from the OFF state to the ON state without operating the automatic steering switch 19.

[0024] In this way, manual mode and automatic mode can be selected alternatively, so that, for example, automatic mode can be selected normally to improve workability by eliminating troublesome operations such as operating the automatic steering switch 19, and manual mode can be selected when there is an obstacle in the field or when the field is specially deformed, allowing automatic steering control to be performed according to the situation.

[0025] Furthermore, when automatically steering the traveling vehicle 1 so that it moves straight along a target traveling line drawn in the field, the left and right marker devices 12 are alternately swung out at each headland turn to draw the target traveling line for the next step, and a camera installed on the traveling vehicle 1 photographs the area in front of the vehicle, and the traveling vehicle 1 is automatically steered based on the left and right positions of the target traveling line in the photographed image.

[0026] As shown in FIG. 5, the virtual target travel line (L1, L2, ... Ln) is automatically calculated by the teaching travel control (described later) when the start point A registration switch 20 is operated at the start position of the reference travel line (L0), which is the first planting step, to register the positioning data of start point A as a first reference position, and the end point B registration switch 21 is operated at the end position of the reference travel line (L0), to register the positioning data of end point B as a second reference position. The distance D0 from the ridge to start point A varies depending on the number of rows that the planting implement 3 can plant, and is pre-stored in the control unit 30. The riding rice transplanter P may be configured to execute a measurement process to measure the distance D0 from the ridge edge. This measurement process allows the start point A to be set accurately and easily, ensuring a headland width that allows the planting implement 3 to ascend and descend without colliding with the ridge.

[0027] In automatic steering control, the lateral deviation amount D and deviation direction θ of the running body 1 relative to the virtual target driving line are calculated based on the coordinate data of the virtual target driving line that is closest to the running body 1 among the calculated virtual target driving lines and the positioning data of the running body 1 by the positioning system 26, and a corrective steering angle θs is calculated based on the lateral deviation amount D and deviation direction θ, and the corrective steering angle θs is output to the steering motor 16, causing the running body 1 to travel along the virtual target driving line.

[0028] When the traveling machine body 1 reaches the end position of the reference traveling line or the virtual target traveling line, the traveling machine body 1 is made to perform a headland turn toward the start position of the next virtual target traveling line based on manual operation of the steering handle 8 by the operator. During the headland turn, the execution of the automatic steering control is restricted by the "automatic steering restriction control during headland turn" (hereinafter sometimes simply referred to as automatic steering restriction control), which will be described later. Specifically, the automatic steering is turned off in response to the turning operation of the steering handle 8, and the operation of switching from the automatic steering off state to the automatic steering on state by the automatic steering switch 19 is restricted. However, restricting the manual switching operation from the automatic steering off state to the automatic steering on state from the start to the end of the headland turn may reduce the accuracy of the work depending on the situation.

[0029] Therefore, the automatic steering restriction control of this embodiment allows a switching operation from the automatic steering OFF state to the automatic steering ON state even during aircraft turning when the aircraft turning angle from the start of the aircraft turning reaches a predetermined angle θ1 or more. This automatic steering restriction control allows for flexibility in the transition from the automatic steering OFF state to the automatic steering ON state. For example, by transitioning from the automatic steering OFF state to the automatic steering ON state during aircraft turning, where the traveling speed is slower than during straight-ahead driving, it is possible to prevent meandering due to overshoot and speed up convergence to the virtual target driving line. In this embodiment, the positioning system 26 determines the aircraft turning angle based on the difference between the aircraft traveling direction measured at the start of the aircraft turning and the aircraft traveling direction measured during the aircraft turning. However, the aircraft turning angle may also be determined based on detection signals from the gyro sensor 54 or a direction sensor.

[0030] Furthermore, the automatic steering control of this embodiment issues a warning if the traveling speed of the traveling vehicle 1 is equal to or greater than a predetermined speed Vt after the automatic steering is switched from an OFF state to an ON state while the traveling vehicle 1 is turning and before the traveling vehicle 1 is aligned with the virtual target traveling line. The warning message "Excessive speed! Please reduce speed" is displayed on the screen of the tablet 29, and the excessive speed warning lamp 23 is illuminated. Such automatic steering control makes it possible to suppress overshooting due to excessive speed.

[0031] Furthermore, the automatic steering control of this embodiment issues a notification that the traveling speed of the traveling machine body 1 can be increased if the traveling machine body 1 is aligned with the virtual target traveling line after the automatic steering is switched from the OFF state to the ON state while the machine body is turning. For example, a notification message saying "On target line, speed increase OK" may be displayed on the screen of the tablet 29, and the speed increase OK notification lamp 24 and the target line notification lamp 50 may be illuminated. Such automatic steering control makes it possible to increase the traveling speed without overshooting, thereby improving work efficiency.

[0032] Next, the processing procedures of the teaching travel control, the automatic steering control in the manual mode, and the automatic steering restriction control that realize the above-mentioned control functions will be described with reference to FIGS.

[0033] The control unit 30 executes teaching travel control when traveling along the reference travel line (L0). As shown in Figure 6, the control unit 30 executing teaching travel control registers positioning data for start point A in response to operation of start point A registration switch 20 at the start position of the reference travel line (L0) (S101), and also registers positioning data for end point B in response to operation of end point B registration switch 21 at the end position of the reference travel line (L0) (S102). Note that the distance from the ridge to point B may be set to distance D0 similar to the measurement of the distance from the ridge to start point A described above, and this distance D0 may be measured using the same measurement method as for start point A.

[0034] Next, the control unit 30 calculates the coordinates of a reference driving line (L0), which is a straight line passing through the starting point A and the ending point B, based on the positioning data of the starting point A and the positioning data of the ending point B (S103), and calculates the coordinates of virtual target driving lines (L1, L2, ... Ln) that are parallel to the reference driving line (L0) at a predetermined interval (S104).

[0035] After the teaching travel control is completed, the control unit 30 executes automatic steering control in manual mode, as shown in FIG. 7. In the flowcharts below, "Y" indicates YES and "N" indicates NO. In the automatic steering control, the control unit 30 first executes automatic steering restriction control, which is a subroutine (S201). In the automatic steering restriction control, as shown in FIG. 8, the control unit 30 first determines whether a steering operation of a predetermined angle θ0 or greater has occurred (S301). If the determination result is YES, the control unit 30 sets the current positioning data (machine position data and machine direction data) as the turning start position and sets the turning flag (S302). The control unit 30 may also determine that a turning operation has started based on the elevation of the planting implement 3. This allows the start of a turning operation to be detected at an appropriate position by raising the planting implement 3, even when the steering handle 8 is heavy.

[0036] When the automatic steering control is in manual mode, the operator can switch from the automatic steering on state to the automatic steering off state by pressing the automatic steering switch 19 when or before performing a turning operation, thereby temporarily suspending the automatic steering (straight-line assist).

[0037] When the turning flag is set (set determination state in step S303), the control unit 30 determines whether the traveling machine body 1 has turned by a predetermined angle θ1 (for example, 90°) or more from the turning start position (S304), and if the result of this determination is NO, the automatic steering is restricted (S305). Here, the automatic steering restricted state is a state in which switching from the automatic steering OFF state to the automatic steering ON state is restricted, and for example, the switching operation from the automatic steering OFF state to the automatic steering ON state by the automatic steering switch 19 is restricted. Therefore, the drive control of the steering motor 16 by the automatic steering control is restricted.

[0038] If the determination result in step S304 is YES, the control unit 30 enters an automatic steering permitted state (S306). Here, the automatic steering permitted state is a state in which switching from an automatic steering OFF state to an automatic steering ON state is permitted, and for example, a switching operation from the automatic steering OFF state to the automatic steering ON state by the automatic steering switch 19 is permitted. Therefore, drive control of the steering motor 16 by automatic steering control is permitted. Then, the control unit 30 determines whether the traveling machine body 1 has turned by a predetermined angle θ2 (e.g., 180°) or more from the turning start position (S307), and if this determination is YES, resets the turning flag (S308).

[0039] Thus, in the automatic steering restriction control, when the operator operates the steering handle 8 to perform a turning operation in which the traveling machine body 1 is rotated by a predetermined angle θ0 (for example, 45°) or more, the point where the turning operation is performed is set as the turning start position (S301, S302). Then, when the traveling machine body 1 has been turned from the posture of the turning start position by an angle equal to or greater than the predetermined angle θ0 (for example, 45°) and less than a predetermined angle θ1 (for example, 90°), the automatic steering restriction state is entered, and, for example, a switching operation from the automatic steering OFF state to the automatic steering ON state by the automatic steering switch 19 is restricted (steps S301, S303, S304, S305).

[0040] Furthermore, when the traveling body 1 has been rotated from the posture of the start position of the turn by an angle greater than a predetermined angle θ1 (e.g., 90°) and less than a predetermined angle θ2 (e.g., 180°), the automatic steering is permitted, and for example, switching operation from the automatic steering off state to the automatic steering on state by the automatic steering switch 19 is permitted (steps S301, S303, S304, S305, S306, S307: N).

[0041] Furthermore, when the traveling machine body 1 turns by a predetermined angle θ2 (for example, 180°) or more from the posture of the turning start position, the turning flag is reset (steps S301, S303, S304, S305, S306, S307, S308). Then, the control unit 30 proceeds with steps S301 and S303: reset and return processing. Even in this state, the control unit 30 maintains the automatic steering permitted state.

[0042] Note that, in addition to automatic steering control, for example, turning control may be implemented when turning. Turning control is initiated based on a turning operation of the riding rice transplanter P (for example, a steering operation at a predetermined angle θ0 or greater), and the control unit 30 turns off the planting clutch and raises the planting implement 3 as the turning starts. The control unit 30 then starts lowering the planting implement 3 so that the planting implement 3 touches the ground at the turning end position, which is a 180-degree turn from the turning start position, and turns on the planting clutch when the planting implement 3 reaches the turning end position. This type of turning control simplifies the operation of the riding rice transplanter P when turning, improving workability.

[0043] After executing the automatic steering restriction control subroutine, the control unit 30 returns to the automatic steering control subroutine, which is a higher-level routine, and then determines whether the automatic steering is permitted (S202), as shown in Fig. 7. If it is determined that the automatic steering is restricted rather than permitted (S202: N), the control unit 30 ends the automatic steering control processing and returns.

[0044] If it is determined that the automatic steering is permitted (S202: Y), the control unit 30 determines whether the automatic steering has been switched from the OFF state to the ON state by the operator pressing the automatic steering switch 19 (S203).

[0045] If it is determined that the automatic steering has been switched to the ON state (S203: Y), the control unit 30 sets an arbitrary virtual target driving line (L1, L2, ... Ln) that is close to the current position as the target driving line (S204). On the other hand, if it is determined that the automatic steering has not been switched to the ON state, that is, if the operator has not pressed the automatic steering switch 19 (S203: N), the control unit 30 determines whether the lateral deviation amount D of the traveling body 1 from the target driving line is equal to or less than a predetermined amount Dauto (S205), whether the deviation direction θ of the traveling body 1 from the target driving line is equal to or less than a predetermined angle θauto (S206), and whether the current speed V is equal to or less than a predetermined value Vauto (S207).

[0046] If the determination results in steps S205, S206, and S207 are all YES, the control unit 30 switches from the automatic steering OFF state to the automatic steering ON state (S215), and sets any virtual target driving line (L1, L2, ... Ln) that is closest to the current position as the target driving line (S204). This allows automatic steering control to continue even if the operator forgets to operate the automatic steering switch 19.

[0047] After step S204, the control unit 30 determines whether the lateral deviation D of the traveling body 1 from the target traveling line (any virtual target traveling line (L1, L2, ... Ln) close to the current position) is equal to or less than a predetermined amount Dt (S208), and determines whether the deviation direction θ of the traveling body 1 from the target traveling line is equal to or less than a predetermined angle θt (S209). Note that the predetermined amount Dt and the predetermined angle θt may be set arbitrarily, but for example, the predetermined amount Dt may be set to be greater than the predetermined amount Dauto, and the predetermined angle θt may be set to be greater than the predetermined angle θauto.

[0048] If the determination results in both steps S208 and S209 are YES, the control unit 30 issues a notification that the traveling speed of the traveling machine body 1 can be increased (S210). On the other hand, if the determination results in at least one of steps S208 and S209 are NO, the control unit 30 calculates a corrective steering angle θs based on the lateral deviation amount D and the deviation direction θ, and outputs the corrective steering angle θs to the steering motor 16 (S211). Next, the control unit 30 determines whether the current speed V is equal to or greater than a predetermined speed Vt (S212), and if the determination result is YES, issues an overspeed warning (S213).

[0049] As described above, the automatic steering restriction control in this embodiment allows the automatic steering OFF state to be switched to the automatic steering ON state even while the aircraft is turning when the aircraft turning angle from the start of turning reaches a predetermined angle θ1 or more, thereby providing flexibility in the transition from the automatic steering OFF state to the automatic steering ON state. For example, by transitioning from the automatic steering OFF state to the automatic steering ON state during turning of the aircraft, where the traveling speed is slower than when traveling straight ahead, it is possible to prevent meandering due to overshooting and to speed up convergence to the virtual target traveling line or the target traveling line.

[0050] In addition, after the automatic steering control is switched from the automatic steering off state to the automatic steering on state while the vehicle is turning, a warning is issued if the traveling speed of the traveling vehicle 1 is equal to or greater than a predetermined speed Vt until the traveling vehicle 1 is aligned with the virtual target traveling line, thereby suppressing overshoot due to speeding up.

[0051] In addition, after the automatic steering control is switched from the automatic steering off state to the automatic steering on state while the vehicle is turning, if the traveling vehicle 1 is aligned with the virtual target traveling line, a notification is given that the traveling speed of the traveling vehicle 1 can be increased, so that the traveling speed can be increased without overshooting, thereby improving work efficiency.

[0052] Next, a modified example of the automatic steering restriction control described in Fig. 8 will be described with reference to Fig. 9. Fig. 9 is a flowchart showing the automatic steering restriction control according to the modified example. Steps S401, S402, S403, S405, S406, and S408 in Fig. 9 are the same as steps S301, S302, S303, S305, S306, and S308 in Fig. 8, and therefore their description will be omitted. That is, only steps S404 and S407 will be mainly described.

[0053] 9, in the automatic steering restriction control according to the modification, when the turning flag is set (set determination state in step S403), the control unit 30 determines whether the traveling machine body 1 has traveled a predetermined distance M1 (for example, a distance corresponding to a turning angle of 90°) or more from the turning start position (S404). After transitioning to the automatic steering permitted state (S406), the control unit 30 determines whether the traveling machine body 1 has traveled a predetermined distance M2 (for example, a distance corresponding to a turning angle of 180°) or more from the turning start position (S407).

[0054] Next, the processing procedure for automatic steering control in automatic mode will be described with reference to Figures 10 and 11. Figure 10 is a diagram showing the travel path of a riding rice transplanter P in a non-rectangular, approximately trapezoidal field (hereinafter referred to as a deformed field), and the following will describe automatic steering control in automatic mode in a deformed field as an example. Note that automatic steering control in automatic mode is not limited to deformed fields, but can also be applied to rectangular fields (hereinafter referred to as a square field), and the control is the same in either case.

[0055] As shown in FIG. 10, in the deformed field DP, as in the case of the rectangular field described in FIG. 5, a reference travel line (L0) is calculated by the teaching travel control, and virtual target travel lines (L1, L2, ... Ln) are automatically calculated. Hereinafter, the direction parallel to the reference travel line (L0) and the virtual target travel lines (L1, L2, ... Ln) is defined as the X direction, and the direction perpendicular to the X direction is defined as the Y direction. In addition, the bottom of the page in FIG. 10 is defined as the +X direction, the top of the page is defined as the -X direction, the right side of the page is defined as the -Y direction, and the left side of the page is defined as the +Y direction. In other words, in the inner planting area of ​​the deformed field DP (the planting area on the inner side of the field), the riding rice transplanter P travels straight in the -X and +X directions along multiple virtual target travel lines (L1, L2, ... Ln) while advancing in the +Y direction. At this time, the traveling machine body 1 of the riding rice transplanter P is automatically steered based on the positioning data detected by the positioning system 26.

[0056] 10 has a shape in which the corners in the +X and +Y directions are cut out to form inclined portions DP1, and planting work must be done on an incline even when planting on the inner periphery in accordance with the shape of the inclined portions DP1. Furthermore, within the deformed field DP, the position of the riding rice transplanter P can be expressed by coordinates in the X and Y directions, and in the following explanation, the position of the riding rice transplanter P will be based on the planting position of the planting implement 3 of the riding rice transplanter P, for example.

[0057] FIG. 11 is a flowchart showing automatic steering control in automatic mode. Note that the automatic steering control in automatic mode described below is performed separately at the end in the +X direction and the end in the -X direction of the deformed field DP. That is, for example, the correction values ​​in steps S502 and S505 described below may be different for the automatic steering control at the end in the +X direction of the deformed field DP and the automatic steering control at the end in the -X direction. Because the automatic steering control itself at both ends of the deformed field DP is substantially the same, only the automatic steering control at the end in the +X direction will be described below. Also, steps S503 to S513 in the flowchart in FIG. 11 are repeatedly performed on imaginary target driving lines L1 to Lk (for example, up to L7 in FIG. 10), but for the sake of explanation, specific positions on the imaginary target driving line are indicated by appropriate parenthesized symbols.

[0058] 11, when automatic steering control in automatic mode is started, the control unit 30 determines whether or not a reference driving line L0 has been generated (S501). If the reference driving line L0 has been generated (S501: Y), the control unit 30 initializes a correction value H, which will be described later, i.e., sets it to 0 (S502).

[0059] Next, the control unit 30 determines whether a turning start position has been recorded (S503). As explained in steps S301 and S302 of FIG. 8, the turning start position is recorded, for example, when a steering operation of a predetermined angle θ0 or more is performed. For example, when a turning operation is performed at point B on the reference driving line L0, the position information (coordinates) of point B is recorded as the turning start position. Also, as mentioned above, the control unit 30 may determine that a turning operation has started based on the fact that the planting machine 3 has risen.

[0060] Next, the control unit 30 proceeds to steps S504 to S506. However, because a predicted turning start position (described later) has not been set for the reference traveling line L0, the processing of steps S504 to S506 is not performed, and the correction value H is set to 0. These steps S504 to S506 will be described later using the target traveling lines L2 to L6 as an example. The control unit 30 then determines whether the riding rice transplanter P has reached the turning end position (X1) (S507), and if the turning end position (X1) has been reached (S507: Y), the control unit 30 transitions to an automatic steering ON state (S508). That is, the control unit 30 sets the virtual target traveling line (L1) as the target traveling line, and controls the steering motor 16 so that the riding rice transplanter P travels along the target traveling line (L1), as described in steps S208 to S213 of FIG. 7.

[0061] The turning end position (X1) has the same coordinate in the X direction as the turning start position (point B). For example, when the X and Y coordinates of the turning start position (point B) are expressed as (x1, y1), the X and Y coordinates of the turning end position (X1) can be expressed as (x1, y1+W). W is the travel distance between each target driving line.

[0062] Next, steps S509 to S513 in FIG. 11 will be described using an example in which the riding rice transplanter P is traveling in the +X direction along the target traveling line L2 in FIG. 10. First, the control unit 30 determines whether or not the advance warning position (E2) has been reached (S509). The advance warning position (E2) is set based on the predicted turn start position (S2) that is set in step S506, which will be described later. On the target traveling line L2, the predicted turn start position (S2) coincides with the turn start position (X2), and the advance warning position (E2) is a position that is a distance D1 short of the predicted turn start position (S2) in the X direction.

[0063] When the riding rice transplanter P reaches the advance notice position (E2) (S509: Y), the control unit 30 issues an advance notice (S510). For example, the advance notice is a process in which the control unit 30 sounds the alarm buzzer 40, and the sounding of the alarm buzzer 40 as the alarm unit may be a continuous sound or an intermittent sound. The advance notice may also be a light on the operation panel 17 or a message displayed on the tablet 29, or a combination of these.

[0064] Next, the control unit 30 determines whether the riding rice transplanter P has reached the automatic steering stop position (F2) (S511). The automatic steering stop position (F2) is a position that is a distance D2 in front of the predicted turning start position (S2) in the X direction. Note that the distance D1 is greater than the distance D2 (D1>D2).

[0065] If the riding rice transplanter P reaches the automatic steering stop position (F2) (S511: Y), the control unit 30 transitions to the automatic steering OFF state (S512). That is, the control unit 30 stops control of the steering handle 8 by the steering motor 16. Next, the control unit 30 determines whether the automatic steering control is set to the automatic mode (S513). If the automatic steering control is set to the automatic mode (S513: Y), the process returns to step S503. If the automatic steering control is not set to the automatic mode (S513: N), the process ends. Note that in step S513, the automatic steering control process ends even if the power switch 18 is not on. In the description of this embodiment, planting work is performed up to the target travel line L7, so it is assumed that the automatic steering control is set to the automatic mode (S513: Y), and the process returns to step S503.

[0066] After the riding rice transplanter P passes the automatic steering stop position (F2), the operator manually drives the riding rice transplanter P so that it follows the target driving line L2. Then, the operator turns the riding rice transplanter P (for example, by steering at a predetermined angle θ0 or more) based on visual estimation or a mark placed in advance.

[0067] In the description of this embodiment, it is assumed that the operator performed a turning operation at the same position as the predicted turning start position (S2). Therefore, the control unit 30 records the same position as the predicted turning start position (S2) as the turning start position (X2) (S503). Next, the control unit 30 determines whether the X coordinate of the turning start position (X2) is outside the correction value maintenance region SK (S504). Here, the correction value maintenance region SK is a range of a predetermined distance (SK / 2) in the +X direction and the -X direction, centered on the predicted turning start position (S2).

[0068] If it is determined that the X coordinate of the turn start position (X2) is outside the correction value maintenance region SK (S504: Y), the control unit 30 updates the correction value H (S505) and proceeds to step S506. That is, the correction value H is updated when the difference between the predicted turn start position and the turn start position is greater than a predetermined distance (SK / 2) as a predetermined value. Also, if it is determined that the X coordinate of the turn start position (X2) is not outside the correction value maintenance region SK, that is, the X coordinate of the turn start position (X2) is within the correction value maintenance region SK (S504: N), the control unit 30 proceeds to step S506 without updating the correction value H. The update of the correction value H will be described with reference to the target driving line L4. Here (target driving line L2), it is assumed that the X coordinate of the turn start position (X2) is within the correction value maintenance region SK. Therefore, the correction value H is not updated when turning at the turn start position (X2). In this way, by providing a correction value maintenance area SK, even if the turning start position recorded due to the operator's turning operation is slightly unstable, the correction value H will not be updated arbitrarily, and advance warning notification and transition to automatic steering off state can be performed stably.

[0069] Next, the control unit 30 sets a predicted turn start position two strokes later (S506). The predicted turn start position two strokes later (S4) is obtained by adding a correction value H to the X coordinate of the turn start position (X2). The correction value H can take a positive value, 0, or a negative value. Here (target driving line L2), the correction value H is 0, so the X coordinate of the predicted turn start position two strokes later (S4) and the turn start position (X2) match.

[0070] Then, the control unit 30 determines whether the riding rice transplanter P has reached the turning end position (X3) (S507), and if the riding rice transplanter P has reached the turning end position (X3) (S507: Y), the control unit 30 transitions to the automatic steering ON state (S508). That is, the control unit 30 sets the virtual target traveling line (L3) as the target traveling line, and controls the steering motor 16 so that the riding rice transplanter P travels along the target traveling line (L3), as described in steps S208 to S213 of FIG.

[0071] Next, steps S509 to S513 in Fig. 11 will be described using an example in which the riding rice transplanter P is traveling in the +X direction along the target travel line L4 in Fig. 10. First, the control unit 30 determines whether or not the advance notice position (E4) has been reached (S509). The advance notice position (E4) is set based on the predicted turn start position (S4) set in step S506, and is a position a distance D1 short of the predicted turn start position (S4) in the X direction.

[0072] If the riding rice transplanter P has reached the advance notice position (E4) (S509: Y), the control unit 30 performs advance notice (S510). Next, the control unit 30 determines whether the riding rice transplanter P has reached the automatic steering stop position (F4) (S511). The automatic steering stop position (F4) is a position that is a distance D2, which is a first distance, in the X direction from the predicted turning start position (S4).

[0073] If the riding rice transplanter P reaches the automatic steering stop position (F4) (S511: Y), the control unit 30 transitions to the automatic steering OFF state (S512). That is, the control unit 30 stops control of the steering handle 8 by the steering motor 16. Next, the control unit 30 determines whether the automatic steering control is set to automatic mode (S513). If the automatic steering control is set to automatic mode (S513: Y), the process returns to step S503. If the automatic steering control is not set to automatic mode (S513: N), the process ends. In the description of this embodiment, planting work is performed up to the target travel line L7, so it is assumed that the automatic steering control is set to automatic mode (S513: Y), and the process returns to step S503.

[0074] Here, due to the slope DP1 of the deformed field DP, the planting work distance for the target travel line L4 is shorter than that for the reference travel line L0 and the target travel lines L1 to L3. Therefore, after the riding rice transplanter P passes the automatic steering stop position (F4), the operator manually operates the riding rice transplanter P so that it follows the target travel line L4, but starts turning at a turning start position (X4) that is a predetermined distance before the predicted turning start position (S4), for example. The control unit 30 records the turning start position (X4) at this time (S503).

[0075] That is, on the target driving line L4, the X coordinates of the turning start position (X4) and the predicted turning start position (S4) are different. Next, the control unit 30 determines whether the X coordinate of the turning start position (X4) is outside the correction value maintaining region SK (S504). Here, it is assumed that the X coordinate of the turning start position (X4) is outside the correction value maintaining region SK.

[0076] Therefore, the control unit 30 determines that the X coordinate of the turn start position (X4) is outside the correction value maintaining region SK (S504: Y), and the control unit 30 updates the correction value H (S505) and proceeds to step S506. The correction value H is calculated from the difference in the X coordinate between the predicted turn start position (S4) of the current course and the turn start position (X4), and is a negative value in this case.

[0077] Next, the control unit 30 sets a predicted turn start position two strokes later (S506). The predicted turn start position two strokes later (S6) is obtained by adding a correction value H (negative value) to the X coordinate of the turn start position (X4).

[0078] Then, the control unit 30 determines whether the riding rice transplanter P has reached the turning end position (X5) (S507), and if the riding rice transplanter P has reached the turning end position (X5) (S507: Y), the control unit 30 transitions to the automatic steering ON state (S508). That is, the control unit 30 sets the virtual target driving line (L5) as the target driving line, and controls the steering motor 16 so that the riding rice transplanter P travels along the target driving line (L5), as described in steps S208 to 213 of FIG.

[0079] Next, steps S509 to S513 in Fig. 11 will be described using an example in which the riding rice transplanter P is traveling in the +X direction along the target traveling line L6 in Fig. 10. First, the control unit 30 determines whether or not the advance notification position (E6) has been reached (S509). The advance notification position (E6) is set based on the predicted turn start position (S6) set in step S506, and is a position that is a distance D1, which is a second distance, before the predicted turn start position (S6) in the X direction.

[0080] If the riding rice transplanter P has reached the advance notice position (E6) (S509: Y), the control unit 30 performs advance notice (S510). Next, the control unit 30 determines whether the riding rice transplanter P has reached the automatic steering stop position (F6) (S511). The automatic steering stop position (F6) is a position a distance D2 short of the predicted turning start position (S6) in the X direction.

[0081] If the riding rice transplanter P reaches the automatic steering stop position (F6) (S511: Y), the control unit 30 transitions to the automatic steering OFF state (S512). That is, the control unit 30 stops control of the steering handle 8 by the steering motor 16. Next, the control unit 30 determines whether the automatic steering control is set to automatic mode (S513). If the automatic steering control is set to automatic mode (S513: Y), the process returns to step S503. If the automatic steering control is not set to automatic mode (S513: N), the process ends. In the description of this embodiment, planting work is performed up to the target travel line L7, so it is assumed that the automatic steering control is set to automatic mode (S513: Y), and the process returns to step S503.

[0082] Here, the target traveling line L6 is a line that intersects with the slope portion DP1 of the deformed field DP, but the slope of the slope portion DP1 is constant and linear. Therefore, as calculated in step S506 above, the predicted turning start position (S6) on the target traveling line L6 is the X coordinate of the turning start position (X4) plus the correction value H (negative value), but the predicted turning start position (S6) coincides with the position where the operator should manually start turning.

[0083] Therefore, after the riding rice transplanter P passes the automatic steering stop position (F6), the operator manually operates the riding rice transplanter P so that it follows the target driving line L6, but starts turning at a turning start position (X6) that coincides with the predicted turning start position (S6), for example. The control unit 30 records the turning start position (X6) at this time (S503). In this way, when traveling along a virtual target driving line corresponding to the inclined portion DP1 inclined at a constant angle, there is almost no deviation between the predicted turning start position and the turning start position, and the correction value H is not updated. Therefore, the advance warning position and automatic steering stop position are set for each target driving line at the same angle as the inclined portion DP1, and advance warning and transition to the automatic steering off state can be performed stably.

[0084] The control unit 30 may sound the alarm buzzer 40 when the predicted turning start position (S6) is reached or immediately before it is reached, thereby notifying the operator of the turning start position. As with the above-described advance notification, the notification buzzer 40 may sound continuously or intermittently for this notification. The notification may also be achieved by turning on a lamp on the operation panel 17 or by displaying a message on the tablet 29, or by a combination of these. This allows the operator to recognize the turning start position even in a deformed field DP, thereby improving workability.

[0085] As described above, in this embodiment, when it is determined that the X coordinate of the turning start position is outside the correction value maintenance area SK during automatic steering control in automatic mode, the correction value H is updated, and the predicted turning start position two strokes later is set using this correction value H. For example, when the riding rice transplanter P travels on a first virtual target travel line (L4), a second virtual target travel line (L5), and a third virtual target travel line (L6) that are adjacent to each other and arranged in order among a plurality of virtual target travel lines (L1 to L7), in the automatic mode, the difference in the X-direction between the predicted turn start position (S4) on the first virtual target travel line (L4) and the turn start position (X4) is calculated as a correction value (H), and the predicted turn start position (S6) on the third virtual target travel line (L6) is calculated by adding the correction value (H) to the X-direction coordinate of the turn start position (X4) on the first virtual target travel line (L4) or the turn end position (X5) on the second virtual target travel line (L5). This makes it possible to set an appropriate predicted turn start position even in a non-rectangular, deformed field DP, and automatically switch to the automatic steering OFF state at the automatic steering stop position calculated based on the predicted turn start position, thereby improving workability.

[0086] Furthermore, if the angle of the inclined portion DP1 of the deformed field DP is constant, the correction value H is not updated thereafter, and the predicted turning start position obtained using the correction value H can be used to provide a warning and transition to the automatic steering off state (automatic steering stopped) at an appropriate position.

[0087] The correction value H is automatically updated during the course of a turning operation, eliminating the need for the operator to manually set the correction value H, making it easy to perform automatic straight-ahead driving. Furthermore, with automatic steering control in automatic mode, the operator does not need to operate the automatic steering switch 19 when starting or ending a turn, improving operability.

[0088] 10, the inclined portion DP1 deforms the field so that it is cut out inward, but if the inclined portion DP1 is provided so as to bulge outward, for example, the correction value H will be a positive value. That is, in step S506, the control unit 30 adds the correction value H (a positive value) to the X coordinate of the turning start position of the current stroke, thereby obtaining the predicted turning start position two strokes later.

[0089] In addition, in this embodiment, the setting of the predicted turn start position (S506) is performed after the turn starts and before the turn ends, but this is not limited to this. For example, the setting of the predicted turn start position (S506) may be performed after the turn ends (S507) and before the advance warning position is reached (S509). The predicted turn start position set at this time will be the predicted turn start position from the current stroke to two strokes later, depending on the timing of setting.

[0090] In addition, in the present embodiment, the predicted turn start position is calculated by adding the correction value H to the X coordinate of the turn start position, but this is not limiting. For example, the predicted turn start position may be calculated by adding the correction value H to the X coordinate of the turn end position.

[0091] <Second embodiment> Next, a second embodiment of the present invention will be described. The second embodiment differs from the first embodiment in that the automatic steering control process in automatic mode is partially different, but the rest is the same. Therefore, the same reference numerals as in the first embodiment are used in the drawings for configurations or processes that are the same as those in the first embodiment, and descriptions thereof will be omitted.

[0092] Fig. 12 is a flowchart showing automatic steering control in automatic mode according to the second embodiment. In the second embodiment, steps S504 to S506 in Fig. 11 described in the first embodiment are omitted, and steps S601 to S603 are added between steps S508 and S509. The other processing is the same as in Fig. 11, and therefore description thereof will be omitted. Below, steps S503, S507 to S508, and S601 to S603 in Fig. 12 will be described using as an example a case where riding rice transplanter P travels along target travel lines L4 and L5 in Fig. 10.

[0093] 12, after the riding rice transplanter P passes the automatic steering stop position (F4), the operator manually drives the riding rice transplanter P along the target driving line L4, but starts turning at a turning start position (X4) that is a predetermined distance before the predicted turning start position (S4). The control unit 30 records the turning start position (X4) at this time (S503).

[0094] That is, on the target travel line L4, the X coordinate of the turning start position (X4) and the predicted turning start position (S4) are different. Next, the control unit 30 determines whether the riding rice transplanter P has reached the turning end position (X5) (S507), and if the turning end position (X5) has been reached (S507: Y), the control unit 30 transitions to the automatic steering ON state (S508). Note that, as explained in the first embodiment, the X coordinate of the turning end position (X5) is the same as the X coordinate of the turning start position (X4).

[0095] Next, the control unit 30 determines whether the X coordinate of the turn end position (X5) is outside the correction value maintenance region SK (S601). As in the first embodiment, the correction value maintenance region SK is a range of a predetermined distance (SK / 2) in the +X direction and the -X direction, centered on the predicted turn start position (S4). Here, it is assumed that the X coordinate of the turn end position (X5) is outside the correction value maintenance region SK.

[0096] Therefore, the control unit 30 determines that the X coordinate of the turning end position (X5) is outside the correction value maintaining region SK (S601: Y), and the control unit 30 updates the correction value H (S602). The correction value H is calculated from the difference in X coordinate between the predicted turning start position (S4) of the previous stroke and the turning end position (X5) of the current stroke.

[0097] Furthermore, the control unit 30 sets a predicted turn start position one stroke later (S603). The predicted turn start position one stroke later (S6) is obtained by adding a correction value H (negative value) to the X coordinate of the turn end position (X5). Steps S509 and later are the same as those in the first embodiment, so their explanation will be omitted.

[0098] As described above, in this embodiment, in automatic steering control in automatic mode, the correction value H is calculated from the difference in X coordinate between the predicted turn start position (S4) of the previous stroke and the turn end position (X5) of the current stroke. For example, when the riding rice transplanter P travels on the first virtual target travel line (L4), the second virtual target travel line (L5), and the third virtual target travel line (L6) that are adjacent to each other and arranged in order among the multiple virtual target travel lines (L1 to L7), in the automatic mode, the difference in position in the X direction between the predicted turn start position (S4) on the first virtual target travel line (L4) and the turn end position (X5) on the second virtual target travel line (L5) is obtained as a correction value (H), and the predicted turn start position (S6) on the third virtual target travel line (L6) is calculated by adding the correction value (H) to the coordinate in the X direction of the turn start position (X4) on the first virtual target travel line (L4) or the turn end position (X5) on the second virtual target travel line (L5). This can achieve the same effects as the first embodiment.

[0099] In this embodiment, the predicted turn start position is calculated by adding the correction value H to the X coordinate of the turn end position, but this is not limiting. For example, the predicted turn start position may be calculated by adding the correction value H to the X coordinate of the turn start position.

[0100] In addition, in each of the above-described embodiments, the riding rice transplanter P has been described as the work vehicle, but the work vehicle is not limited to this. The work vehicle may be, for example, a tractor, a combine harvester, or another work vehicle. [Explanation of symbols]

[0101] 1 Running body 8 Steering wheel 9 Running gear (front wheels) 10 Running gear (rear wheels) 19 Operation unit (automatic steering switch) 26 Positioning System 30 Control Unit 40 Alarm section (alarm buzzer) P Work vehicle (riding rice transplanter) θ Predetermined angle

Claims

1. A work vehicle comprising a traveling machine body supported by a traveling device, a positioning system that detects positioning data of the work vehicle, and a control unit that can perform automatic steering that automatically steers the traveling machine body based on the positioning data detected by the positioning system so that the work vehicle travels straight in a predetermined direction along a plurality of virtual target traveling lines that are parallel to each other and that are calculated in advance, the control unit has an automatic mode in which, at an automatic steering stop position determined based on a turning start predicted position, the control unit automatically transitions from an automatic steering ON state in which the automatic steering is performed to an automatic steering OFF state in which the automatic steering is not performed, and automatically transitions from the automatic steering OFF state to the automatic steering ON state at a turning end position whose coordinate in the predetermined direction is the same as a turning start position at which a turning operation for moving to the adjacent virtual target driving line is started, When the work vehicle travels on a first virtual target driving line, a second virtual target driving line, and a third virtual target driving line that are adjacent to each other and arranged in order among the plurality of virtual target driving lines, in the automatic mode, a difference in position in the predetermined direction between the predicted turning start position on the first virtual target driving line and the turning start position is obtained as a correction value, and the predicted turning start position on the third virtual target driving line is calculated by adding the correction value to the coordinate in the predetermined direction of the turning start position on the first virtual target driving line or the turning end position on the second virtual target driving line. A work vehicle characterized by:

2. A work vehicle comprising a traveling machine body supported by a traveling device, a positioning system that detects positioning data of the work vehicle, and a control unit that can perform automatic steering that automatically steers the traveling machine body based on the positioning data detected by the positioning system so that the work vehicle travels straight in a predetermined direction along a plurality of virtual target traveling lines that are parallel to each other and that are calculated in advance, the control unit has an automatic mode in which, at an automatic steering stop position determined based on a turning start predicted position, the control unit automatically transitions from an automatic steering ON state in which the automatic steering is performed to an automatic steering OFF state in which the automatic steering is not performed, and automatically transitions from the automatic steering OFF state to the automatic steering ON state at a turning end position whose coordinate in the predetermined direction is the same as a turning start position at which a turning operation for moving to the adjacent virtual target driving line is started, When the work vehicle travels on a first virtual target driving line, a second virtual target driving line, and a third virtual target driving line that are adjacent to each other and arranged in order among the plurality of virtual target driving lines, in the automatic mode, a difference in position in the predetermined direction between the predicted turning start position on the first virtual target driving line and the turning end position on the second virtual target driving line is obtained as a correction value, and the predicted turning start position on the third virtual target driving line is calculated by adding the correction value to the coordinate in the predetermined direction of the turning start position on the first virtual target driving line or the turning end position on the second virtual target driving line. A work vehicle characterized by:

3. the control unit updates the correction value when the difference is greater than a predetermined value in the automatic mode.

3. A work vehicle according to claim 1 or 2.

4. On the same virtual target driving line, the automatic steering stop position is a position that is a first distance before the predicted turning start position.

4. A work vehicle according to claim 1, wherein the work vehicle is a vehicle having a plurality of shafts.

5. Further provided with a notification unit, the control unit, in the automatic mode, activates the notification unit at a notice position on the same virtual target driving line that is a second distance before the predicted turning start position, the second distance being greater than the first distance.

5. The work vehicle according to claim 4.

6. Further provided is a steering handle for steering the traveling machine body, The control unit determines that the turning operation has started when the steering wheel is operated by an angle equal to or greater than a predetermined angle.

6. A work vehicle according to claim 1.

7. the control unit, in the automatic mode, calculates the turning start predicted position based on the same correction value for the third virtual target driving line and subsequent virtual target driving lines as long as the correction value is not updated.

7. A work vehicle according to claim 1.

8. the control unit is capable of executing a measurement process for measuring a distance from a ridge to a first reference position, and sets a reference driving line passing through the first reference position and the second reference position by registering the first reference position and a second reference position different from the first reference position within the field; 8. A work vehicle according to claim 1.

9. Further provided is an operation unit for switching between the automatic steering ON state and the automatic steering OFF state, The control unit has a manual mode that switches between the automatic steering ON state and the automatic steering OFF state based on operation of the operation unit.

9. A work vehicle according to claim 1.

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