Tractor

Abstract

To easily correct position in automatic steering.SOLUTION: A tractor includes: a vehicle body; a steering handle manually operated to manually steer the vehicle body; a positioning device provided on the vehicle body and detecting the position of the vehicle body on the basis of a signal from a positioning satellite; an operation member operable to set a planned driving line; an automatic steering mechanism that executes automatic steering of the vehicle body separately from manual steering by the steering handle on the basis of the planned driving line set by the operation of the operation member and a calculated vehicle body position, which is the position of the vehicle body detected by the positioning device; a correction switch operable to steer the vehicle body separately from the steering handle during the movement of the vehicle body by the automatic steering; and a display device that displays a screen for changing the correction amount per operation unit of the correction switch.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to, for example, a tractor. [Background technology]

[0002] Patent Document 1 discloses a conventional agricultural work machine. The agricultural work machine in Patent Document 1 includes a traveling machine body that can switch between manual traveling using manual steering and automatic traveling using automatic steering along a set traveling line that is set parallel to a reference traveling line, and a selector switch that can switch between manual traveling and automatic traveling. Furthermore, the agricultural work machine sets the start point of the reference traveling line after pressing the right instruction button while traveling along a ridge, and sets the end point of the reference traveling line by pressing the left instruction button while traveling. In other words, the reference traveling line is set before automatic steering. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2017-123803 Summary of the Invention [Problem to be solved by the invention]

[0004] The agricultural implement disclosed in Patent Document 1 can be easily driven automatically by switching from manual driving to automatic driving using a selector switch. However, the automatic driving disclosed in Patent Document 1 is unable to correct the position of the agricultural implement when the positioning accuracy of the positioning device decreases, for example. SUMMARY OF THE INVENTION In view of the above problems, an object of the present invention is to provide a tractor that can easily correct the position during automatic steering. [Means for solving the problem]

[0005] The technical means of the present invention for solving this technical problem is characterized by the following points. The tractor includes a vehicle body, a steering handle manually operated to manually steer the vehicle body, a positioning device provided on the vehicle body and detecting the position of the vehicle body based on signals from positioning satellites, an operating member operable to set a planned travel line, an automatic steering mechanism that automatically steers the vehicle body separately from manual steering using the steering handle based on the planned travel line set by operating the operating member and a calculated vehicle body position which is the position of the vehicle body detected by the positioning device, and The position of the vehicle where the deviation occurred , and steers the vehicle body separately from the steering handle. By doing so, the amount of correction to be made in the direction to eliminate the deviation is set. and a compensation switch operable for a control device that steers the vehicle body using the automatic steering mechanism based on the correction amount set by operating the correction switch; and a display device that displays a screen for changing the correction amount per operation unit of the correction switch.

[0006] The correction switch includes a first correction unit that steers the vehicle body in one direction and a second correction unit that steers the vehicle body in another direction, and the display device displays the correction amount per operation unit, which is the same value and is commonly changed by the first correction unit and the second correction unit.

[0007] The display device displays on the screen a symbol mark indicating the start point of a driving reference line for setting the planned driving line, and a symbol mark indicating the end point of the driving reference line.

[0008] The correction amount is set to an amount corresponding to the number of times the correction switch is operated, and the operation unit of the correction switch is the number of times it is operated.

[0009] The correction switch includes a first correction unit that can be pressed to steer the vehicle body in one direction, and a second correction unit that can be pressed to steer the vehicle body in another direction, and the number of operations is the number of times the first correction unit or the second correction unit is pressed. [Effects of the Invention]

[0010] According to the present invention, position correction can be easily performed in automatic steering. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 2 is a diagram showing the configuration and control block diagram of a tractor. [Figure 2] FIG. 2 is an explanatory diagram illustrating automatic steering. [Figure 3A] FIG. 10 is an explanatory diagram illustrating a correction amount in a push switch. [Figure 3B] FIG. 10 is an explanatory diagram illustrating a correction amount in a slide switch. [Figure 4A] 4A and 4B are diagrams illustrating a first correction unit and a second correction unit in the push switch. [Figure 4B] 10A and 10B are diagrams illustrating a first correction unit and a second correction unit in the slide switch. [Figure 5A] This shows the state when the calculated vehicle body position is shifted to the right while driving straight under automatic steering. [Figure 5B] This shows the state when the calculated vehicle body position is shifted to the left while driving straight under automatic steering. [Figure 6] This is a view of the cover in front of the driver's seat as seen from the driver's seat side. [Figure 7] FIG. 2 is an explanatory diagram illustrating automatic steering. [Figure 8] 10 is an explanatory diagram illustrating a structure for changing the position of the working implement in the width direction of the machine body. FIG. [Figure 9] FIG. 10 is an explanatory diagram illustrating how the positioning device obtains a position while correcting the position using measurement information. [Figure 10A] FIG. 10 is a diagram showing an example of a setting screen M30. [Figure 10B] FIG. 10 is a diagram showing an example of a setting screen M31. [Figure 11] FIG. 4 is a diagram showing the relationship between a steering changeover switch, a second control device, and a steering motor. [Figure 12] FIG. 10 is a diagram illustrating the operation of braking control. [Figure 13A] FIG. 10 is a diagram illustrating braking when the positional deviation between the tractor and the planned travel line does not become less than a threshold value. [Figure 13B]FIG. 10 is a diagram illustrating braking when the heading deviation between the tractor and the planned travel line does not become less than a threshold value. [Figure 14A] 10A and 10B are diagrams illustrating a state in which the position of the working implement is changed so as to approach the planned travel line. [Figure 14B] 10A and 10B are diagrams illustrating a state in which the position of the working implement is changed so as to move away from the planned travel line. [Figure 15] FIG. 10 is a diagram showing an operation screen M1. [Figure 16] FIG. 1 is an overall view of a tractor. DETAILED DESCRIPTION OF THE INVENTION

[0012] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. Figure 16 is a side view showing one embodiment of the work vehicle 1, and Figure 16 is a plan view showing one embodiment of the work vehicle 1. In this embodiment, the work vehicle 1 is a tractor. However, the work vehicle 1 is not limited to tractors, and may be an agricultural machine (agricultural vehicle) such as a combine harvester or transplanter, or a construction machine (construction vehicle) such as a loader work machine.

[0013] In the following description, the front side of the driver seated in the driver's seat 10 of the tractor (work vehicle) 1 (the direction of the arrow A1 in FIG. 16) is referred to as the front, the rear side of the driver (the direction of the arrow A2 in FIG. 16) is referred to as the rear, the left side of the driver as the left side, and the right side of the driver as the right side. In the following description, the horizontal direction is the width direction of the vehicle body. As shown in FIG. 16, the tractor 1 includes a body 3, a prime mover 4, and a transmission 5. The body 3 has a traveling device 7 and is capable of traveling. The traveling device 7 is a device having front wheels 7F and rear wheels 7R. The front wheels 7F may be of either a tire type or a crawler type. The rear wheels 7R may also be of either a tire type or a crawler type.

[0014] The prime mover 4 is a diesel engine, an electric motor, or the like, and in this embodiment is configured as a diesel engine. The transmission 5 is capable of switching the propulsive force of the traveling device 7 by changing gears, and is also capable of switching the traveling device 7 between forward and reverse. A driver's seat 10 is provided on the vehicle body 3. Furthermore, a coupling section 8 is provided at the rear of the vehicle body 3. The working implement 2 can be attached and detached to and from the coupling section 8. By coupling the working implement 2 to the coupling section 8, the working implement 2 can be towed by the vehicle body 3. The working implement 2 is a tilling implement for tilling, a fertilizer spreader for spreading fertilizer, a pesticide spreader for spreading pesticide, a harvesting implement for harvesting, a reaping implement for reaping grass or the like, a spreading implement for spreading grass or the like, a grass collecting implement for collecting grass or the like, a shaping implement for shaping grass or the like, etc.

[0015] As shown in Figure 1, the transmission 5 includes a main shaft (propeller shaft) 5a, a main transmission section 5b, an auxiliary transmission section 5c, a shuttle section 5d, a PTO power transmission section 5e, and a front transmission section 5f. The propeller shaft 5a is rotatably supported in a housing case (transmission case) of the transmission 5, and power is transmitted to the propeller shaft 5a from the crankshaft of the prime mover 4. The main transmission section 5b has multiple gears and a shifter that changes the connections of the gears. The main transmission section 5b changes and outputs (shifts) the rotation input from the propeller shaft 5a by appropriately changing the connections (meshing) of the multiple gears using the shifter.

[0016] Similar to the main transmission unit 5b, the sub-transmission unit 5c has a plurality of gears and a shifter for changing the connection of the gears. The sub-transmission unit 5c changes and outputs (shifts) the rotation input from the main transmission unit 5b by appropriately changing the connection (meshing) of the plurality of gears with the shifter. The shuttle unit 5d has a shuttle shaft 12 and a forward / reverse switching unit 13. Power output from the sub-transmission unit 5c is transmitted to the shuttle shaft 12 via gears or the like. The forward / reverse switching unit 13 is composed of, for example, a hydraulic clutch or the like, and switches the rotation direction of the shuttle shaft 12, i.e., the forward and reverse movement of the tractor 1, by engaging and disengaging the hydraulic clutch. The shuttle shaft 12 is connected to a rear wheel differential device 20R. The rear wheel differential device 20R rotatably supports a rear axle 21R to which the rear wheels 7R are attached.

[0017] The PTO power transmission section 5e has a PTO propeller shaft 14 and a PTO clutch 15. The PTO propeller shaft 14 is rotatably supported and can transmit power from the propeller shaft 5a. The PTO propeller shaft 14 is connected to a PTO shaft 16 via gears or the like. The PTO clutch 15 is composed of, for example, a hydraulic clutch, and by engaging and disengaging the hydraulic clutch, the state switches between transmitting the power of the propeller shaft 5a to the PTO propeller shaft 14 and not transmitting the power of the propeller shaft 5a to the PTO propeller shaft 14.

[0018] The front transmission unit 5f has a first clutch 17 and a second clutch 18. The first clutch 17 and the second clutch can transmit power from the propeller shaft 5a, and for example, the power of the shuttle shaft 12 is transmitted via a gear and a transmission shaft. The power from the first clutch 17 and the second clutch 18 can be transmitted to the front axle 21F via a front transmission shaft 22. Specifically, the front transmission shaft 22 is connected to a front wheel differential device 20F, and the front wheel differential device 20F rotatably supports the front axle 21F to which the front wheels 7F are attached.

[0019] The first clutch 17 and the second clutch 18 are configured by hydraulic clutches or the like. An oil line is connected to the latch 17, and the oil line is connected to a first operating valve 25 to which hydraulic oil discharged from a hydraulic pump is supplied. The first clutch 17 is switched between an engaged state and a disengaged state depending on the opening degree of the first operating valve 25. An oil line is connected to the second clutch 18, and the oil line is connected to a second operating valve 26. The second clutch 18 is switched between an engaged state and a disengaged state depending on the opening degree of the second operating valve 26. The first operating valve 25 and the second operating valve 26 are, for example, two-position switching valves with solenoid valves, and are switched between the engaged state and the disengaged state by energizing or deenergizing the solenoids of the solenoid valves.

[0020] When the first clutch 17 is disengaged and the second clutch 18 is engaged, the power of the shuttle shaft 12 is transmitted to the front wheels 7F via the second clutch 18. As a result, the front and rear wheels are driven by power, resulting in four-wheel drive (4WD), and the rotational speeds of the front and rear wheels are approximately the same (4WD constant speed state). On the other hand, when the first clutch 17 is engaged and the second clutch 18 is disengaged, the vehicle is in four-wheel drive, and the rotational speed of the front wheels is faster than the rotational speed of the rear wheels (4WD acceleration state). Furthermore, when the first clutch 17 and the second clutch 18 are disengaged, the power of the shuttle shaft 12 is not transmitted to the front wheels 7F, resulting in two-wheel drive (2WD), where the rear wheels are driven by power.

[0021] As shown in FIG. 1, the tractor 1 is equipped with a braking device. The braking device includes a left braking device 46a and a right braking device 46b. The left braking device 46a and the right braking device 46b are disc-type braking devices that can be switched between a braking state in which braking is applied and a release state in which braking is released. The left braking device 46a is provided on the left side of the rear axle 21R, and the right braking device 46b is provided on the right side of the rear axle 21R. For example, a left brake pedal and a right brake pedal are provided near the driver's seat 10. When the driver operating the tractor 1 operates (depresses) the left brake pedal, a left connecting member 47a connected to the left brake pedal moves in the braking direction, thereby placing the left braking device 46a in a braking state. When the driver operates (depresses) the right brake pedal, a right connecting member 47b connected to the right brake pedal moves in the braking direction, thereby placing the right braking device 46b in a braking state.

[0022] A left hydraulic actuator 48a that operates using hydraulic oil is connected to the left connecting member 47a. A third operating valve (left braking valve) 49a is connected to the left hydraulic actuator 48a via an oil passage. The left hydraulic actuator 48a is operated by the third operating valve 49a, thereby moving the left connecting member 47a in the braking direction. A right hydraulic actuator 48b that operates using hydraulic oil is connected to the right connecting member 47b. A fourth operating valve (right braking valve) 49b is connected to the right hydraulic actuator 48b via an oil passage. The right hydraulic actuator 48b is operated by the fourth operating valve 28b, thereby moving the right connecting member 47b in the braking direction.

[0023] As described above, the left braking device 46a and the right braking device 46b can independently brake the left rear wheel 7R and the right rear wheel 7R not only by operating the left brake pedal and the right brake pedal, but also by operating the left hydraulic actuating unit 48a and the right hydraulic actuating unit 48b. 8, the position of the working device 2 can be changed in the width direction of the vehicle body. The connecting portion 8 includes a first swinging portion 800a connected to the rear of the vehicle body 3 so as to be swingable in the width direction of the vehicle body, a second swinging portion 800b connected to the rear of the vehicle body 3 so as to be swingable in the width direction of the vehicle body and provided spaced apart from the first swinging portion 800a, and a hydraulic actuator 800c having at least one end connected to the vehicle body 3 and the other end connected to either the first swinging portion 800a or the second swinging portion 800b. The front portion of the working device 2 is swingably connected to the rear portion of the first swinging portion 800a, and the front portion of the working device 2 is swingably connected to the rear portion of the second swinging portion 800b.

[0024] The hydraulic actuator 800c is, for example, a hydraulic cylinder that expands and contracts using hydraulic pressure. The hydraulic actuator 800 is operated by a switching valve 801, i.e., the hydraulic cylinder is extended or contracted by switching the switching valve 801 to one side, and the other side, respectively. The extension and contraction of the hydraulic cylinder allows the first swinging part 800a and the second swinging part 800b to be repositioned to one side (e.g., the left side) or the other side (e.g., the right side) of the width of the machine body. In the above-described embodiment, the position of the working device 2 is changed in the width direction of the machine body by swinging the first swinging part 800a and the second swinging part 800b, but this is not limiting. The connecting part 8 may be configured by a slide mechanism that moves the working device 2 along a rail or the like, and the position of the working device 2 in the width direction of the machine body may be changed by the operation of the slide mechanism.

[0025] The tractor 1 is equipped with a positioning device 40. The positioning device 40 can detect its own position (positioning information including latitude and longitude) using a satellite positioning system (positioning satellite) such as D-GPS, GPS, GLONASS, Beidou, Galileo, or Michibiki. That is, the positioning device 40 receives satellite signals (position of the positioning satellite, transmission time, correction information, etc.) transmitted from the positioning satellites and detects its position (e.g., latitude and longitude) based on the satellite signals. The positioning device 40 includes a receiving device 41 and an inertial measurement unit (IMU) 42. The receiving device 41 has an antenna and the like and receives satellite signals transmitted from the positioning satellites, and is attached to the vehicle body 3 separately from the IMU 42. In this embodiment, the receiving device 41 is attached to a ROPs provided on the vehicle body 3. Note that the attachment location of the receiving device 41 is not limited to that described in the embodiment.

[0026] The inertial measurement unit 42 has an acceleration sensor that detects acceleration, a gyro sensor that detects angular velocity, etc. The inertial measurement unit 42 is provided on the vehicle body 3, for example, below the driver's seat 10, and can detect the roll angle, pitch angle, yaw angle, etc. of the vehicle body 3. The positioning device 40 corrects the position of the vehicle body 3 (tractor 1) using measurement information detected by the inertial measurement unit 42. As shown in FIG. 9 , the positioning device 40 applies satellite signals to global navigation satellite system (GNSS) to calculate the position, speed, and orientation as first positioning information, which is positioning information. The positioning device 40 applies the measurement information (acceleration and angular velocity) detected by the inertial measurement unit 42 to the inertial navigation system (INS) to calculate the position, speed, and orientation as second positioning information, which is positioning information. The positioning device 40 also applies the first positioning information (position, speed, and orientation) obtained by the global navigation satellite system (GNSS) and the second positioning information (position, speed, and orientation) obtained by the inertial navigation system (INS) to a Kalman filter to calculate third positioning information, which is positioning information. That is, the positioning device 40 calculates the position, speed, and orientation as the third positioning information using hybrid navigation (combined navigation). That is, the positioning device 40 uses the second observation information obtained from the measurement information (acceleration, angular velocity) to correct the first observation information obtained by satellite navigation (GNSS), and determines the position of the vehicle body 3 (tractor 1) as the third observation information. Note that the parameter settings for hybrid navigation (combined navigation) are settings that emphasize accuracy in straight-line traveling. Furthermore, the Kalman filter is described in many documents, and is disclosed, for example, in Japanese Patent Application Laid-Open No. 2004-239643.

[0027] As shown in Fig. 1, the tractor 1 is equipped with a steering device 11. The steering device 11 is a device capable of performing manual steering, in which the vehicle body 3 is steered by operation by the driver, and automatic steering, in which the vehicle body 3 is steered automatically without operation by the driver. The steering device 11 has a steering handle (steering wheel) 30 and a steering shaft (rotation shaft) 31 that rotatably supports the steering handle 30. The steering device 11 also has an assist mechanism (power steering device) 32. The assist mechanism 32 assists the rotation of the steering shaft 31 (steering handle 30) by hydraulic pressure or the like. The assist mechanism 32 includes a hydraulic pump 33, a control valve 34 to which hydraulic oil discharged from the hydraulic pump 33 is supplied, and a steering cylinder 35 that is operated by the control valve 34. The control valve 34 is, for example, a three-position switching valve that can be switched by moving a spool or the like, and switches in accordance with the steering direction (rotation direction) of the steering shaft 31. The steering cylinder 35 is connected to an arm (knuckle arm) 36 that changes the direction of the front wheels 7F.

[0028] Therefore, when the driver grips the steering wheel 30 and turns it in one direction or the other, the switching position and opening of the control valve 34 are switched in accordance with the direction of rotation of the steering wheel 30, and the steering cylinder 35 expands or contracts to the left or right according to the switching position and opening of the control valve 34, thereby changing the steering direction of the front wheels 7F. In other words, the traveling direction of the vehicle body 3 can be changed to the left or right by manually steering the steering wheel 30.

[0029] Next, automatic steering will be described. As shown in Figure 2, when performing automatic steering, a driving reference line L1 is first set before automatic steering is performed. After setting the driving reference line L1, automatic steering can be performed by setting a planned driving line L2 that is parallel to the driving reference line L1. In automatic steering, the tractor 1 (vehicle body 3) is automatically steered in the direction of travel so that the vehicle position measured by the positioning device 40 matches the planned driving line L2.

[0030] Specifically, before automatic steering is performed, the tractor 1 (body 3) is moved to a predetermined position in the field (S1), and when the driver operates the steering selector switch 52 provided on the tractor 1 at the predetermined position (S2), the body position measured by the positioning device 40 is set as the start point P10 of the traveling reference line L1 (S3). Furthermore, the tractor 1 (body 3) is moved from the start point P10 of the traveling reference line L1 (S4), and when the driver operates the steering selector switch 52 at the predetermined position (S5), the body position measured by the positioning device 40 is set as the end point P11 of the traveling reference line L1 (S6). Therefore, a straight line connecting the start point P10 and the end point P11 is set as the traveling reference line L1.

[0031] After the travel reference line L1 is set (after S6), for example, if the tractor 1 (body 3) is moved to a location different from the location where the travel reference line L1 was set (S7), and the driver operates the steering selector switch 52 (S8), a planned travel line L2, which is a straight line parallel to the travel reference line L1, is set (S9). After the planned travel line L2 is set, automatic steering is initiated, and the traveling direction of the tractor 1 (body 3) is changed to align with the planned travel line L2. For example, if the current body position is on the left side of the planned travel line L2, the front wheels 7F are steered to the right, and if the current body position is on the right side of the planned travel line L2, the front wheels 7F are steered to the left. Note that during automatic steering, the travel speed (vehicle speed) of the tractor 1 (body 3) can be changed by the driver manually changing the amount of operation of an accelerator member (accelerator pedal, accelerator lever) provided on the tractor 1 or by changing the gear position of a transmission.

[0032] Furthermore, after automatic steering has started, the driver can end automatic steering by operating the steering selector switch 52 at any point. That is, the end point of the planned traveling line L2 can be set by ending automatic steering by operating the steering selector switch 52. In other words, the length from the start point to the end point of the planned traveling line L2 can be set longer or shorter than the traveling reference line L1. In other words, the planned traveling line L2 is not associated with the length of the traveling reference line L1, and the planned traveling line L2 allows the vehicle to travel a distance longer than the length of the traveling reference line L1 while being automatically steered.

[0033] As shown in FIG. 1, the steering device 11 has an automatic steering mechanism 37. The automatic steering mechanism 37 is a mechanism that automatically steers the vehicle body 3, and automatically steers the vehicle body 3 based on the position of the vehicle body 3 (vehicle body position) detected by the positioning device 40. The automatic steering mechanism 37 includes a steering motor 38 and a gear mechanism 39. The steering motor 38 is a motor that can control the rotation direction, rotation speed, rotation angle, etc. based on the vehicle body position. The gear mechanism 39 includes a gear that is provided on the steering shaft 31 and rotates together with the steering shaft 31, and a gear that is provided on the rotation shaft of the steering motor 38 and rotates together with the rotation shaft. When the rotation shaft of the steering motor 38 rotates, the steering shaft 31 automatically rotates (turns) via the gear mechanism 39, and the steering direction of the front wheels 7F can be changed so that the vehicle body position coincides with the intended traveling line L2.

[0034] As shown in Fig. 1, the tractor 1 is equipped with a display device 45. The display device 45 is a device capable of displaying various information related to the tractor 1, and is capable of displaying at least driving information of the tractor 1. The display device 45 is provided in front of the driver's seat 10. As shown in Fig. 1, the tractor 1 is equipped with a setting switch 51. The setting switch 51 is a switch that switches to a setting mode in which at least settings before the start of automatic steering are made. The setting mode is a mode in which various settings related to automatic steering are made before the start of automatic steering, such as a mode in which the start point and end point of the driving reference line L1 are set.

[0035] The setting switch 51 can be switched between ON and OFF, and when ON it outputs a signal indicating that the setting mode is enabled, and when OFF it outputs a signal indicating that the setting mode is disabled. Furthermore, when the setting switch 51 is ON it outputs a signal indicating that the setting mode is enabled to the display device 45, and when OFF it outputs a signal indicating that the setting mode is disabled to the display device 45.

[0036] The tractor 1 is equipped with a steering selector switch 52. The steering selector switch 52 is a switch that switches between starting and ending automatic steering. Specifically, the steering selector switch 52 can be switched from a neutral position to up, down, forward, or backward, and outputs a command to start automatic steering when the steering selector switch 52 is switched from the neutral position to down while the setting mode is enabled, and outputs a command to end automatic steering when the steering selector switch 52 is switched from the neutral position to up while the setting mode is enabled. Furthermore, when the steering selector switch 52 is switched from the neutral position to backward while the setting mode is enabled, the steering selector switch 52 outputs a command to set the current vehicle body position to the start point P10 of the driving reference line L1, and when the steering selector switch 52 is switched from the neutral position to forward while the setting mode is enabled, the steering selector switch 52 outputs a command to set the current vehicle body position to the end point P11 of the driving reference line L1. That is, the steering changeover switch 52 also serves as a reference line setting switch that sets the start position (start point P10) and end position (end point P11) of the driving reference line L1. Note that the steering changeover switch 52, which switches the start or end of automatic steering, may be configured separately from the reference line setting switch.

[0037] The tractor 1 is equipped with a correction switch 53. The correction switch 53 is a switch that corrects the vehicle body position (latitude, longitude) measured by the positioning device 40. In other words, the correction switch 53 is a switch that corrects the vehicle body position (referred to as a calculated vehicle body position) calculated using satellite signals (position of the positioning satellite, transmission time, correction information, etc.) and measurement information (acceleration, angular velocity) measured by the inertial measurement unit 42.

[0038] The correction switch 53 is configured as a push switch that can be pressed or a slide switch that can be slid. Below, the cases where the correction switch 53 is a push switch and a slide switch will be described. If the correction switch 53 is a push switch, the correction amount is set based on the number of times the push switch is operated. The correction amount is determined by the formula: correction amount = number of operations x correction amount per operation (correction amount per unit). For example, as shown in FIG. 3A, the correction amount increases by several centimeters or several tens of centimeters each time the push switch is operated. The number of times the push switch is operated is input to the first control device 60A, which sets (calculates) the correction amount based on the number of operations. Note that the first control device 60A can change the correction amount per operation of the push switch by a predetermined operation. As shown in FIG. 10A, when a predetermined operation is performed on the display device 45, the first control device 60A displays a setting screen M30 on the display device 45 for setting the correction amount. The setting screen M30 displays a setting input section 91 for inputting the correction amount per operation of the push switch (correction amount per unit). The correction amount per unit in the setting input section 91 can be input by operating the display device 45. The correction amount per unit input to the setting input unit 91 of the display device 45 can be stored in the first control device 60A. That is, by inputting the correction amount per unit to the setting input unit 91, it is possible to change the correction amount per unit shown in Fig. 3A from 2 cm to 4 cm, for example.

[0039] Furthermore, if the correction switch 53 is a slide switch, the correction amount is set based on the operation amount (displacement amount) of the slide switch. For example, the correction amount is determined by the amount of displacement from a predetermined position. For example, as shown in FIG. 3B, the correction amount increases by several centimeters or several tens of centimeters for every 5 mm increase in the displacement amount of the slide switch. The operation amount (displacement amount) of the slide switch is input to the first control device 60A, which sets (calculates) the correction amount based on the displacement amount. Note that even if the correction switch 53 is a slide switch, the correction amount can be changed in the same way as with a push switch.

[0040] As shown in FIG. 10B, when a predetermined operation is performed on the display device 45, the first control device 60A displays a setting screen M31 on the display device 45 for setting the correction amount. The setting screen M31 displays a setting input section 92 for inputting a correction amount (correction amount per unit) for the displacement amount of the slide switch by a predetermined operation of the slide switch. The correction amount per unit in the setting input section 92 can be input by operating the display device 45, and the input correction amount per unit can be stored in the first control device 60A. That is, by inputting the correction amount per unit in the setting input section 92, for example, the correction amount (correction amount per unit) for every 5 mm increase in the displacement amount can be changed from 2 cm to 4 cm, as shown in FIG. 3B. Note that the method and rate of increase of the correction amount described above are not limited to the above-mentioned values.

[0041] 4A and 4B, the correction switch 53 has a first correction unit 53A and a second correction unit 53B. The first correction unit 53A is a unit that issues a command to correct the vehicle body position corresponding to one side in the width direction of the vehicle body 3, i.e., the left side. The second correction unit 53B is a unit that issues a command to correct the vehicle body position corresponding to the other side in the width direction of the vehicle body 3, i.e., the right side. As shown in FIG. 4A, when the correction switch 53 is a push switch, the first correction unit 53A and the second correction unit 53B are ON / OFF switches that automatically return to their original state each time they are operated. The switch constituting the first correction unit 53A and the switch constituting the second correction unit 53B are integrated. Note that the switch constituting the first correction unit 53A and the switch constituting the second correction unit 53B may be disposed apart from each other. As shown in FIG. 3A, each time the first correction unit 53A is pressed, the correction amount corresponding to the left side of the vehicle body 3 (left correction amount) increases. Furthermore, each time the second correction unit 53B is pressed, the correction amount corresponding to the right side of the vehicle body 3 (right correction amount) increases.

[0042] As shown in FIG. 4B , when the correction switch 53 is a slide switch, the first correction unit 53A and the second correction unit 53B include a knob 55 that moves left or right along the longitudinal direction of the slot. When the correction switch 53 is a slide switch, the first correction unit 53A and the second correction unit 53B are spaced apart from each other in the width direction. As shown in FIG. 3B , when the knob 55 is gradually displaced leftward from a predetermined reference position, the left correction amount increases according to the amount of displacement. Similarly, when the knob 55 is gradually displaced rightward from a predetermined reference position, the right correction amount increases according to the amount of displacement. Note that, as shown in FIG. 4B , when the correction switch 53 is a slide switch, the first correction unit 53A and the second correction unit 53B may be integrally formed, the reference position of the knob 55 may be set to the center, and the left correction amount may be set when the knob 55 is moved leftward from the reference position, and the right correction amount may be set when the knob 55 is moved rightward from the middle position.

[0043] Next, the relationship between the correction amount (left correction amount, right correction amount) by the correction switch 53, the intended travel line L2, and the behavior (travel trajectory) of the tractor 1 (vehicle body 3) will be described. FIG. 5A shows a state in which the calculated vehicle body position W1 deviates to the right while traveling straight during automatic steering. As shown in FIG. 5A, when automatic steering is initiated, if the actual position (actual position W2) of the tractor 1 (vehicle body 3) matches the calculated vehicle body position W1, and if the actual position W2 matches the planned traveling line L2, the tractor 1 travels along the planned traveling line L2. That is, in section P1 where there is no error in the positioning by the positioning device 40 and the vehicle body position (calculated vehicle body position W1) detected by the positioning device 40 is the same as the actual position W2, the tractor 1 travels along the planned traveling line L2. Note that if there is no error in the positioning by the positioning device 40 and no correction is made, the calculated vehicle body position W1 and the vehicle body position corrected with the correction amount (corrected vehicle body position) W3 are the same value. The corrected vehicle body position W3 is calculated vehicle body position W3 = calculated vehicle body position W1 - correction amount.

[0044] Here, suppose that near position P20, even though actual position W2 is not deviated from planned traveling line L2, various influences cause an error in the positioning of positioning device 40, causing vehicle body position W1 detected by positioning device 40 to deviate to the right from planned traveling line L2 (actual position W2), and deviation amount W4 is maintained. Then, tractor 1 determines that a deviation has occurred between calculated vehicle body position W1 and planned traveling line L2, and steers tractor 1 left to eliminate deviation amount W4 between calculated vehicle body position W1 and planned traveling line L2. Then, steering left shifts actual position W2 of tractor 1 toward planned traveling line L2. Suppose that the driver subsequently notices that tractor 1 is deviated from planned traveling line L2 and steers second correction unit 53B at position P21 to increase the right correction amount from zero. A right correction amount is added to the calculated vehicle body position W1, and the corrected vehicle body position (corrected vehicle body position) W3 can be made substantially the same as the actual position W2. In other words, by setting the right correction amount using the second correction unit 53B, the vehicle body position of the positioning device 40 can be corrected in a direction that eliminates the deviation amount W4 that occurred near position P20. Note that, as shown in position P21 in FIG. 5A, if the actual position W2 of the tractor 1 is away to the left from the intended travel line L2 after the vehicle body position is corrected, the tractor 1 is steered to the right, and the actual position W2 of the tractor 1 can be made to coincide with the intended travel line L2.

[0045] Figure 5B shows a state in which the calculated vehicle body position W1 deviates to the left while traveling straight during automatic steering. As shown in Figure 5B, when automatic steering is started, if the actual position W2 and the calculated vehicle body position W1 coincide and the actual position W2 and the planned traveling line L2 coincide, the tractor 1 travels along the planned traveling line L2, as in Figure 5A. That is, as in Figure 5A, in section P2 where there is no error in the positioning by the positioning device 40, the tractor 1 travels along the planned traveling line L2. Also, as in Figure 5A, the calculated vehicle body position W1 and the corrected vehicle body position W3 are the same value.

[0046] Here, suppose that at position P22, an error occurs in the positioning of the positioning device 40 due to various influences, causing the vehicle body position W1 detected by the positioning device 40 to deviate to the left relative to the actual position W2, and the deviation amount W5 is maintained. Then, the tractor 1 steers to the right so as to eliminate the deviation amount W5 between the calculated vehicle body position W1 and the planned traveling line L2. Thereafter, suppose that the driver notices that the tractor 1 has deviated from the planned traveling line L2, and steers the first correction unit 53A at position P23 to increase the left correction amount from zero. Then, the left correction amount is added to the calculated vehicle body position W1, and the corrected vehicle body position (corrected vehicle body position) W3 can be made substantially the same as the actual position W2. In other words, by setting the left correction amount by the first correction unit 53A, the tractor 1 steers to the right in a direction that eliminates the deviation amount W5 that occurred near position P22. The vehicle body position of the positioning device 40 can be corrected. Note that, as shown in position P23 in Figure 5B, if the actual position W2 of the tractor 1 is away to the right from the planned traveling line L2 after the vehicle body position has been corrected, the tractor 1 is steered to the left, and the actual position W2 of the tractor 1 can be aligned with the planned traveling line L2.

[0047] Next, the setting switch 51 and the correction switch 53 will be described. As shown in Fig. 6, the outer periphery of the steering shaft 31 is covered by a steering post 180. The outer periphery of the steering post 180 is covered by a cover 177. The cover 177 is provided in front of the driver's seat 10. The cover 177 includes a panel cover 178 and a column cover 179.

[0048] The panel cover 178 supports the display device 45. An upper plate portion 178a of the panel cover 178 is provided with a support portion 178e that supports the display device 45. The support portion 178e supports the display device 45 in front of the steering shaft 31 and below the steering handle 30. The upper plate portion 178a also has a mounting surface 178f to which the setting switch 51 and the correction switch 53 are attached. The mounting surface 178f is provided rearward of the support portion 178e and below the steering handle 30. The support portion 178e and the mounting surface 178f are continuous, with the support portion 178e located in front of the upper plate portion 178a and the mounting surface 178f located in rearward of the upper plate portion 178a. The setting switch 51 and the correction switch 53 are attached to the mounting surface 178f. As a result, the setting switch 51 and the correction switch 53 are arranged around the steering shaft 31.

[0049] A shuttle lever 181 protrudes from the left plate portion 178b of the panel cover 178. The shuttle lever 181 is a member that switches the traveling direction of the vehicle body 3. To explain in more detail, by operating (swinging) the shuttle lever 181 forward, the forward / reverse travel switching unit 13 enters a state in which it outputs forward power to the traveling device 7, and the traveling direction of the vehicle body 3 is switched to the forward direction. In addition, by operating (swinging) the shuttle lever 181 backward, the forward / reverse travel switching unit 13 enters a state in which it outputs reverse power to the traveling device 7, and the traveling direction of the vehicle body 3 is switched to the reverse direction. When the shuttle lever 181 is in the neutral position, no power is output to the traveling device 7.

[0050] The column cover 179 is disposed below the steering wheel 30 and covers the periphery of the upper part of the steering shaft 31. The column cover 179 is formed in a substantially rectangular tubular shape and protrudes upward from the mounting surface 178f of the panel cover 178. In other words, the mounting surface 178f is provided around the periphery of the column cover 179. Therefore, the setting switch 51 and the correction switch 53 attached to the mounting surface 178f are disposed around the periphery of the column cover 179.

[0051] Next, a detailed description will be given of the locations of the setting switch 51, steering changeover switch 52, and correction switch 53. As shown in Fig. 6, the setting switch 51, steering changeover switch 52, and correction switch 53 are arranged around the steering shaft 31. The setting switch 51 is disposed on one side (left) of the steering shaft 31. The steering changeover switch 52 is disposed on one side (left) of the steering shaft 31. In this embodiment, the steering changeover switch 52 is configured as a swingable lever. The steering changeover switch 52 can swing around a base end provided on the steering shaft 31 side as a fulcrum. The base end of the steering changeover switch 52 is provided inside the column cover 179. The steering changeover switch 52 protrudes from one side (left) of the column cover 179.

[0052] The correction switch 53 is disposed on the other side (right side) of the steering shaft 31. More specifically, the correction switch 53 is disposed to the right and rear (diagonally rear right) of the steering shaft 31. In terms of its position relative to the column cover 179, the correction switch 53 is disposed to the right and rear (diagonally rear right) of the column cover 179. In terms of its position relative to the mounting surface 178f of the panel cover 178, the correction switch 53 is disposed at the rear right of the mounting surface 178f. By disposing the correction switch 53 at the rear of the inclined mounting surface 178f, a long distance can be secured between the correction switch 53 and the steering wheel 30. This makes it possible to more reliably prevent unintentional operation of the correction switch 53 and unintentional steering of the steering wheel 30.

[0053] As described above, the setting switch 51, steering changeover switch 52, and correction switch 53 are arranged around the steering shaft 31. In other words, the setting switch 51, steering changeover switch 52, and correction switch 53 are concentrated around the steering shaft 31. This allows the driver to clearly understand the location of each switch at a glance. In addition, the driver can operate each switch without changing his / her posture while remaining seated in the driver's seat 10. This improves operability and prevents erroneous operation. In addition, the harnesses (wiring) routed from each switch can be shortened.

[0054] It should be noted that the above-described switch arrangement may be reversed between left and right. That is, one side may be the left and the other side may be the right, or one side may be the right and the other side may be the left. Specifically, for example, the setting switch 51 and the steering changeover switch 52 may be arranged on the right side of the steering shaft 31, and the correction switch 53 may be arranged on the left side of the steering shaft 31.

[0055] As shown in Fig. 1, the tractor 1 is equipped with a plurality of control devices 60. The plurality of control devices 60 are devices that control the traveling system, the working system, calculate the vehicle body position, etc. of the tractor 1. The plurality of control devices 60 are a first control device 60A, a second control device 60B, and a third control device 60C. The first control device 60A receives satellite signals (received information) received by the receiving device 41 and measurement information (acceleration, angular velocity, etc.) measured by the inertial measurement device 42, and calculates the vehicle body position based on the received information and the measurement information. For example, if the correction amount by the correction switch 53 is zero, i.e., if correction of the vehicle body position by the correction switch 53 is not instructed, the first control device 60A does not correct the calculated vehicle body position W1 calculated from the received information and the measurement information, and determines the calculated vehicle body position W1 as the vehicle body position to be used during automatic steering. On the other hand, if correction of the vehicle body position by the correction switch 53 is instructed, the first control device 60A sets the correction amount for the vehicle body position based on either the number of times the correction switch 53 is operated or the operation amount (displacement amount) of the correction switch 53, and determines the corrected vehicle body position W3 obtained by correcting the calculated vehicle body position W1 with the correction amount as the vehicle body position to be used during automatic steering.

[0056] The first control device 60A sets a control signal based on the vehicle body position (calculated vehicle body position W1, corrected vehicle body position W3) and the intended traveling line L2, and outputs the control signal to the second control device 60B. The second control device 60B has an automatic steering control unit 200. The automatic steering control unit 200 is composed of electric and electronic circuits provided in the second control device 60B, programs stored in a CPU, etc. The automatic steering control unit 200 controls the steering motor 38 of the automatic steering mechanism 37 based on the control signal output from the first control device 60A so that the vehicle body 3 travels along the intended traveling line L2.

[0057] 7, when the deviation between the vehicle body position and the planned travel line L2 is less than the threshold value, the automatic steering control unit 200 maintains the rotation angle of the rotation shaft of the steering motor 38. When the deviation between the vehicle body position and the planned travel line L2 is equal to or greater than the threshold value and the tractor 1 is positioned on the left side of the planned travel line L2, the automatic steering control unit 200 changes the steering direction of the tractor 1 to the right. If the deviation between the vehicle body position and the planned travel line L2 is equal to or greater than a threshold value and the tractor 1 is positioned to the right of the planned travel line L2, the automatic steering control unit 200 rotates the rotation shaft of the steering motor 38 so that the steering direction of the tractor 1 is leftward. In the above-described embodiment, the steering angle of the steering device 11 is changed based on the deviation between the vehicle body position and the planned travel line L2. However, if the orientation of the planned travel line L2 and the orientation (vehicle body orientation) F1 of the traveling direction (traveling direction) of the tractor 1 (vehicle body 3) differ, that is, if the angle θg of the vehicle body orientation F1 with respect to the planned travel line L2 is equal to or greater than a threshold value, the automatic steering control unit 200 may set the steering angle so that the angle θg is zero (the vehicle body orientation F1 matches the orientation of the planned travel line L2). Furthermore, the automatic steering control unit 200 may set the final steering angle in automatic steering based on the steering angle calculated based on the deviation (position deviation) and the steering angle calculated based on the heading (heading deviation). The setting of the steering angle in automatic steering in the above-described embodiment is an example and is not limiting. As described above, the control device 60 can automatically steer the tractor 1 (vehicle body 3).

[0058] Now, when the steering changeover switch 52 is switched to start automatic steering, current may be supplied to the second control device 60B, and when it is switched to end automatic steering, current may not be supplied to the second control device 60B. FIG. 11 is a diagram showing the relationship between the steering changeover switch 52, the second control device 60B, and the steering motor 38. As shown in FIG. 11, a plurality of cutoff switches 77 are connected to the power supply line L50 of the second control device 60B. The plurality of cutoff switches 77 include a first cutoff switch 77a and a second cutoff switch 77b. The first cutoff switch 77a and the second cutoff switch 77b are switchable between a cutoff position 78 that cuts off the power supply line L50 and an energized position 79 that energizes the power supply line L50. The first cutoff switch 77a and the second cutoff switch 77b are, for example, relays that switch ON / OFF, and are switched to the energized position 79 when ON, and are switched to the cutoff position 78 when OFF.

[0059] The steering selector switch 52 is connected to the first cutoff switch 77a and the second cutoff switch 77b. The steering selector switch 52 includes a selector 52a, an input terminal 52b, and an output terminal 52c. The selector 52a is a part that switches between at least a first position (start position, end position) and a second position (neutral position). For example, the selector 52a is a switch that switches to the first position when pressed and then automatically returns to the second position. When the selector 52a is in the first position (start position, end position), the input terminal 52b is connected to the output terminal 52c, and when the selector 52a is in the second position (neutral position), the input terminal 52b is connected to the output terminal 52c. The input terminal 52b is connected to a power supply line L50, and the output terminal 52c is connected to the coil terminals of the first cutoff switch 77a and the second cutoff switch 77b via an output line L51. The output line L51 branches into an output line L52 which is connected to the display device 45.

[0060] When automatic steering has ended, if the switching unit 52a of the steering selector switch 52 is changed from the second position to the first position, the steering selector switch 52 issues a command to start automatic steering. When the steering selector switch 52 issues a command to start automatic steering, that is, when the switching unit 52a is changed to the first position, the switching unit 52a connects the input terminal 52b and the output terminal 52c. As a result, the coils of the first cutoff switch 77a and the second cutoff switch 77b are excited, and the first cutoff switch 77a and the second cutoff switch 77b are switched to and maintained in the conducting position 79.

[0061] On the other hand, when a command to start automatic steering is being issued, if the steering changeover switch 52 is changed from the second position to the first position again, the steering changeover switch 52 issues a command to end automatic steering. When the switching unit 52a is turned on, the input terminal 52b and the output terminal 52c are connected by the switching unit 52a. As a result, the coils of the first cutoff switch 77a and the second cutoff switch 77b are excited, and the first cutoff switch 77a and the second cutoff switch 77b are switched from the conducting position 79 to the cutoff position 78, and the cutoff position 78 is maintained.

[0062] In other words, the first shut-off switch 77a and the second shut-off switch 77b switch to the energized position 79 when the steering changeover switch 52 issues a command to start automatic steering, and switch to the shut-off position 78 when the steering changeover switch 52 issues a command to end automatic steering. Now, when the tractor 1 deviates from the planned driving line L2, and the steering angle of the steering device 11 is set in a direction that brings the tractor 1 closer to the planned driving line L2 through automatic steering, but the tractor 1 does not approach the planned driving line L2, the automatic steering control unit 200 performs braking control on the front wheels 7F and / or rear wheels 7R.

[0063] In the braking control, for example, braking is performed on one of the two rear wheels (first wheel) 7R and the two rear wheels (second wheel) 7R that are aligned in the width direction. In addition, in the braking control, for example, braking is performed on one of the two front wheels (first wheel) 7F and the two front wheels (second wheel) 7F that are aligned in the width direction. Braking control will be explained below using braking of the rear wheel 7R as an example. 12, after the start of automatic steering, if the automatic steering control unit 200 sets the steering angle of the steering device 11 so that the tractor 1 returns to the intended travel line L2, the automatic steering control unit 200 checks whether the tractor 1 has returned to the intended travel line L2 (S21). If the tractor 1 does not return to the intended travel line L2 during automatic steering, that is, if the tractor 1 does not approach the intended travel line L2 (S21, No), the automatic steering control unit 200 executes braking control (S22).

[0064] For example, if the automatic steering control unit 200 sets the steering angle to eliminate the deviation (position deviation, azimuth deviation), and the vehicle body position does not move in the steering direction, the automatic steering control unit 200 brakes either the first wheel or the second wheel that corresponds to the steering direction in which the automatic steering was performed. Specifically, as shown in Fig. 13A, if the automatic steering control unit 200 steers the front wheel 7F to the right at position P1 and the position deviation between the tractor 1 and the intended travel line L2 does not become less than the threshold even after a predetermined time has elapsed, the automatic steering control unit 200 outputs a control signal to the right brake valve 49b through braking control, and reduces the rotational speed of the right rear wheel 7R by braking the right brake device 46b.

[0065] As in Figure 13A, if the automatic steering control unit 200 steers the front wheel 7F to the left at position P1 and the position deviation between the tractor 1 and the intended driving line L2 does not become less than the threshold value even after a predetermined time has elapsed, the automatic steering control unit 200 outputs a control signal to the left brake valve 49a through braking control, and reduces the rotational speed of the left rear wheel 7R by braking the left brake device 46a. According to the above, when the tractor 1 does not approach the intended travel line L2 during automatic steering, the automatic steering control unit 200 brakes the wheel corresponding to the steering direction, out of the first wheel and the second wheel.

[0066] Next, the automatic steering control unit 200 determines whether the position deviation is less than the threshold value after the braking control (S23), and if the position deviation is less than the threshold value (S23, Yes), ends the braking control (S24). The automatic steering control unit 200 may set the brakes on either the left rear wheel 7R or the right rear wheel 7R when the direction indicated by the planned travel line L2 differs from the travel direction of the tractor 1. For example, as shown in Fig. 13B, if the automatic steering control unit 200 steers the front wheel 7F to the right at position P2 and the direction deviation between the tractor 1 and the planned travel line L2 does not become less than the threshold value even after a predetermined time has elapsed, the automatic steering control unit 200 outputs a control signal to one of the right brake valves 49b by braking control, and reduces the rotation speed of the right rear wheel 7R by braking the right brake device 46b. Can.

[0067] As in Figure 13B, if the automatic steering control unit 200 steers the front wheel 7F to the left at position P4 and the heading deviation between the tractor 1 and the intended driving line L2 does not become less than the threshold value even after a predetermined time has elapsed, the automatic steering control unit 200 outputs a control signal to the left brake valve 49a through braking control, and reduces the rotational speed of the left rear wheel 7R by braking the left brake device 46a. As described above, even if the steering angle of the steering device 11 is changed by automatic steering, and the tractor 1 does not approach the intended travel line L2, the automatic steering control unit 200 applies one brake and changes the direction of the tractor 1, allowing the tractor 1 to approach the intended travel line L2. For example, if the field is muddy or inclined, the direction of the tractor 1 may not be changed by automatic steering, but as described above, applying one brake makes it possible to change the direction of the tractor 1. Note that if the position deviation is equal to or greater than a threshold value and the orientation deviation θ is equal to or greater than a threshold value, i.e., if both the position deviation and the orientation deviation are equal to or greater than a threshold value, the automatic steering control unit 200 may perform braking control.

[0068] When the automatic steering control unit 200 is operating, the position of the work implement 2 may be changed in the vehicle body width direction based on the vehicle body position of the tractor 1 and the planned travel line L2. As shown in FIG. 14A , when the positional deviation between the tractor 1 and the planned travel line L2 is equal to or greater than a threshold value L10, the third control unit 60C changes the position of the work implement 2 toward the planned travel line L2. For example, the third control unit 60C acquires the positional deviation from the automatic steering control unit 200 and monitors the transition of the positional deviation. When the positional deviation is being monitored and the positional deviation does not decrease even after the tractor 1 has traveled a predetermined distance—for example, when the tractor 1 is traveling with the positional deviation at L10—the third control unit 60C outputs a control signal to the switching valve 801 to shift the work implement 2 in the vehicle body width direction toward the planned travel line L2 by a distance equal to the positional deviation L10. According to this, when the tractor 1 is traveling off the planned traveling line L2, the working implement 2 can be moved onto the planned traveling line L2, and the working position of the working implement 2 can be positioned on the planned traveling line L2.

[0069] In FIG. 14A, when the position deviation between the tractor 1 and the planned traveling line L2 is equal to or greater than a threshold value, the position of the work implement 2 is changed toward the planned traveling line L2. However, instead of this, when automatic steering changes from a state in which there is a position deviation to a state in which the position deviation is eliminated, the work implement 2 may be moved in the opposite direction to the direction in which the position deviation is eliminated. As shown in FIG. 14B , assume that the positional deviation between the tractor 1 and the intended travel line L2 is L10 in the deviation section T100. If the tractor 1 gradually approaches the intended travel line L2 due to automatic steering in the deviation section T100, the third control device 60C moves the work implement 2 in a direction away from the intended travel line L2 as the tractor 1 approaches the intended travel line L2. That is, by outputting a control signal to the switching valve 801 in the deviation section T100, the third control device 60C changes the position of the work implement 2 so that the distance between the widthwise center of the work implement 2 and the intended travel line L2 is the same as L10, which is the positional deviation. Also, in the deviation resolution section T101 where the positional deviation between the tractor 1 and the intended travel line L2 is zero, that is, where the tractor 1 has reached the intended travel line L2, the position of the work implement 2 is changed so that the distance between the widthwise center of the work implement 2 is the same as in the deviation section T100. This allows the position of the work implement 2 to be maintained constant even when the tractor 1 approaches the intended travel line L2 due to a position deviation.

[0070] As described above, when calculating the vehicle body position (calculated vehicle body position W1, corrected vehicle body position W3), the measurement information (acceleration, angular velocity) detected by the inertial measurement unit 42 is used. However, the measurement information detected by the inertial measurement unit 42 may contain an increase in the integrated value of bias error (amount of drift). When the amount of drift exceeds a predetermined value, the display device 45 displays that the amount of drift has exceeded the predetermined value. For example, the first control device 60A may use the inertial measurement unit 42 The amount of drift of the inertial measurement unit 42 is monitored, and when the amount of drift exceeds a predetermined value, a message such as "Please reset IMU" is displayed on the driving screen M1 of the display device 45 as shown in FIG. 15 to indicate that the amount of drift has exceeded the predetermined value, i.e., to indicate that the inertial measurement unit 42 should be reset.

[0071] The operation screen M1 has an operation display section 61 that displays operation information. The operation display section 61 includes a rotation display section 62 that displays the rotation speed of the prime mover 4 (prime mover rotation speed) as operation information. The rotation display section 62 includes a level display section 63. The level display section 63 is a section that displays the prime mover rotation speed in stages. For example, the level display section 63 includes a scale section 65 and an indicator section 80. The scale section 65 has, for example, a first line 65A and a plurality of second lines 65B allocated at predetermined intervals along the first line 65A. The scale section 65 also has a third line 65C spaced apart from the first line 65A at a predetermined interval. The first line 65A and the third line 65C are formed, for example, in a semicircular shape, with one end (for example, the left side) representing the minimum value and the other end (for example, the right side) representing the maximum value.

[0072] The indicator portion 80 is a bar whose length changes depending on the magnitude of the motor rotation speed. For example, the indicator portion 80 is located between the first line 65A and the third line 65C. When the motor rotation speed is at its minimum value of zero, the indicator portion 80 is located at one end (left side) of the first line 65A and the third line 65C and is shortest in length. When the motor rotation speed is at its maximum value, the indicator portion 80 extends from one end (left side) of the first line 65A and the third line 65C to the other end (right side) of the first line 65A and the third line 65C and is longest in length. The rotary display portion 62 includes a numeric display portion 64. The numeric display portion 64 displays the motor rotation speed in numbers. For example, the rotary display portion 62 is located inside the semicircle of the first line 65A and the third line 65C.

[0073] Therefore, the operation display unit 61 can display the prime mover rotation speed, such as the engine rotation speed, in stages using the level display unit 63 and can also display it numerically using the rotation display unit 62. The driving screen M1 has an icon display section 67 that displays a plurality of icon sections 66. The icon display section 67 is a section that shows various information using the icon sections 66. That is, settings related to driving such as automatic steering, for example, the setting state set in the setting mode, are displayed in the icon section 66. The icon display section 67 is located in a different position from the driving display section 61, for example, at the top of the driving screen M1.

[0074] The multiple icon sections 66 are a first icon section 66A, a second icon section 66B, a third icon section 66C, a fourth icon section 66D, a fifth icon section 66E, a sixth icon section 66F, and a seventh icon section 66G. Note that the driving screen M1 does not need to have all of the multiple icon sections 66 (66A, 66B, 66C, 66D, 66E, 66F, 66G) and is not limited to the above-described embodiment.

[0075] The first icon section 66A is displayed when a warning occurs. The second icon section 66B is displayed when a start point P10 of the driving reference line L1 is set. The third icon section 66C is displayed when an end point P11 of the driving reference line L1 is set. The fourth icon section 66D is displayed when automatic steering is permitted. For example, the fourth icon section 66D is displayed when the setting mode is enabled and the setting of the driving reference line L1 is completed. By looking at the fourth icon section 66D, the operator can understand that automatic steering is permitted. Then, the operator can start automatic steering by operating the steering selector switch 52.

[0076] The fifth icon section 66E is displayed when the connecting portion 8 is in the lifting / lowering state. The sixth icon section 66F is displayed when the 4WD is in the speed increasing state. The seventh icon section 66G changes color etc. depending on the reception sensitivity of the reception device 41. As described above, when the driving screen M1 indicates that the drift amount has reached a predetermined value or more, the drift amount of the inertial measurement unit 42 can be reset. For example, a reset switch 195 that resets the inertial measurement unit 42 is connected to a control device 60 such as the first control device 60A. The reset switch 195 is provided around the driver's seat 10. As shown in FIG. 15 , the reset switch 195 may be displayed on the driving screen of the display device 45. When the drift amount is greater than or equal to a predetermined value, the first control device 60A accepts operation of the reset switch 195. When the operation of the reset switch 195 is acquired, the first control device 60A initializes (resets) the inertial measurement unit 42, thereby initializing the drift amount. When the drift amount is not greater than or equal to a predetermined value, the first control device 60A preferably does not initialize the inertial measurement unit 42 even if the reset switch 195 is operated. Furthermore, the first control device 60A preferably initializes the inertial measurement unit 42 when automatic steering is terminated by operation of the steering selector switch 52 and the reset switch 195 is operated.

[0077] The work vehicle 1 includes a vehicle body 3, a steering wheel 30 for steering the vehicle body 3, a positioning device 40 mounted on the vehicle body 3 and detecting the position of the vehicle body 3 based on signals from positioning satellites, an automatic steering mechanism 37 for automatically steering the vehicle body 3 based on the position of the vehicle body 3 detected by the positioning device 40, separately from manual steering by the steering wheel 30, a correction switch 53 that can set a correction amount for the position of the vehicle body 3 detected by the positioning device 40, and a control device 60 (first control device 60A) that controls the automatic steering of the automatic steering mechanism 37 and can change the correction amount in a predetermined operation of the correction switch 53. This allows the position of the vehicle body 3 detected by the positioning device 40 to be easily corrected by operating the correction switch 53. Furthermore, by changing the correction amount of the correction switch 53, the position of the vehicle body 3 corrected by operating the correction switch 53 can be adjusted. For example, the correction amount per operation of the correction switch 53 and the correction amount per operation amount can be changed arbitrarily.

[0078] The automatic steering mechanism 37 automatically steers the vehicle body based on the corrected vehicle body position W3, which is the position of the vehicle body 3 corrected based on the correction amount, and the planned traveling line L2. This allows the tractor 1 to travel along the planned traveling line L2 based on the corrected vehicle body position W3, even if a positioning error occurs in the positioning satellite, for example. The vehicle is equipped with a traveling device 7 having a first wheel provided on one side of the vehicle body 3 in the width direction and a second wheel provided on the other side of the vehicle body 3 in the width direction, and braking devices (left braking device 46a, right braking device 46b) that can brake either the first wheel or the second wheel, and the braking devices (left braking device 46a, right braking device 46b) brake either the first wheel or the second wheel to eliminate the deviation when the deviation between the position of the vehicle body 3 and the intended traveling line L2 is equal to or greater than a predetermined value. Thus, even if the tractor 1 (vehicle body 3) is steered during automatic steering but does not approach the intended traveling line L2 (the deviation cannot be eliminated), the tractor 1 can be brought closer to the intended traveling line L2 by braking the braking devices.

[0079] The positioning device 40 is equipped with an inertial measurement unit 42 that detects the inertia of the vehicle body 3 and corrects the position of the vehicle body 3 based on the detected inertia, a display device that displays when the drift amount of the inertial measurement unit 42 reaches a predetermined value or more, and a reset switch 195 that resets the inertial measurement unit 42. This allows an operator or the like to easily grasp that the drift amount measured by the inertial measurement unit 42 is increasing, and the drift amount can be initialized by operating the reset switch 195.

[0080] The work vehicle 1 is equipped with a work device 2 that is mounted on a vehicle body 3 and has an adjustable working width, and the work device 2 changes its position based on the deviation between the position of the vehicle body 3 and the planned traveling line L2. In this way, for example, if the deviation is large and the vehicle body 3 deviates from the planned traveling line L2, the position of the work device 2 can be brought closer to the planned traveling line L2, so that the work position of the work device 2 is on the planned traveling line L2 even if the vehicle body 3 is away from the planned traveling line L2. On the other hand, for example, when the vehicle body 3 approaches the intended travel line L2 from a situation where the deviation is large and the vehicle body 3 is far from the intended travel line L2, the position of the working implement 2 can be maintained in the state it was in before it approached the intended travel line L2.

[0081] The work vehicle 1 is equipped with a steering changeover switch 52 that issues commands to start and end automatic steering, and the automatic steering mechanism 37 has a steering motor 38 that can rotate a steering post that supports the steering wheel 30, and a cutoff switch 77 that is connected to a power line L50 of a control device 60 (second control device 60B) that performs automatic steering by controlling the rotation of the steering motor 38 and can be switched between a cutoff position 78 that cuts off the power line L50 and an energized position 79 that energizes the power line L50, and the cutoff switch 77 switches to the energized position 79 when the steering changeover switch 52 issues a command to start automatic steering, and switches to the cutoff position 78 when the steering changeover switch 52 issues a command to change from start to end automatic steering. According to this, when automatic steering is switched from start to end using the steering changeover switch 52, power is no longer supplied to the control device 60 (second control device 60B) that controls the automatic steering, so that automatic steering can be reliably stopped in response to the switching of the steering changeover switch 52.

[0082] The work vehicle 1 is equipped with a steering changeover switch 52 that switches between starting and ending automatic steering, and the control device 60 (first control device 60A) starts automatic steering by the steering device when the steering changeover switch 52 switches to start automatic steering. This allows automatic steering to be performed easily by operating the steering changeover switch 52. The work vehicle 1 is equipped with a positioning device 40 that can detect the position of the vehicle body, and a reference line setting switch that sets the vehicle body position detected by the positioning device 40 as the start position and end position of the traveling reference line L1. This makes it easy to set the traveling reference line L1 using the reference line setting switch.

[0083] The embodiments disclosed herein should be considered to be illustrative in all respects and not restrictive. The scope of the present invention is defined by the claims, not by the above description, and is intended to include all modifications within the meaning and scope of the claims. [Explanation of symbols]

[0084] 1 Work vehicle 3. Body 7 Running gear 30 Steering wheel 37 Automatic steering mechanism 38 Steering motor 40 Positioning device 42 Inertial Measurement Unit 45 Display device 46a, 46b Left braking device, right braking device 52 Steering switch 53 Correction switch 53A First Correction Unit 53B 2nd correction section 60 Control device 60A First control device 60B Second control device 66B (Indicating the starting point) Second icon section 66C (End point) Third icon 77 Cut-off switch 78 Shut-off position 79 Energized position 91 Setting input section 92 Setting input section 195 Reset Switch L1 Driving reference line L2 Planned running line L50 power line P10 (Start point of driving reference line) P11 End point (of driving reference line)

Claims

1. The car body and a steering handle that is manually operated to manually steer the vehicle body; a positioning device provided on the vehicle body and detecting a position of the vehicle body based on a signal from a positioning satellite; An operating member operable to set a planned travel line; an automatic steering mechanism that performs automatic steering of the vehicle body separately from manual steering by the steering handle, based on the planned travel line set by the operation of the operating member and a calculated vehicle body position, which is the position of the vehicle body detected by the positioning device; a correction switch operable to set a correction amount for correcting a position of the vehicle body, in which a deviation has occurred during the movement of the vehicle body under the automatic steering, in a direction to eliminate the deviation by steering the vehicle body separately from the steering handle; a control device that uses the automatic steering mechanism to steer the vehicle body based on the correction amount set by operating the correction switch; a display device that displays a screen for changing the correction amount per operation unit of the correction switch; A tractor comprising:

2. the correction switch includes a first correction unit that steers the vehicle body in one direction and a second correction unit that steers the vehicle body in another direction; The tractor according to claim 1 , wherein the display device displays the correction amount per operation unit, which is the same value in the first correction unit and the second correction unit and is commonly changed.

3. 3. The tractor according to claim 1, wherein the display device displays on the screen a symbol mark indicating a start point of a driving reference line for setting the planned driving line, and a symbol mark indicating an end point of the driving reference line.

4. The correction amount is set to an amount corresponding to the number of times the correction switch is operated, 2. The tractor according to claim 1, wherein the operation unit of the correction switch is the number of operations.

5. The correction switch includes a first correction unit that can be pressed to steer the vehicle body in one direction. a second correction unit that can be pressed to steer the vehicle body in another direction, The tractor according to claim 4 , wherein the number of operations is the number of times the first correction unit or the second correction unit is pressed.

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