JP2024096414A - Work vehicles - Google Patents

Abstract

To make it possible to appropriately stop automatic steering according to the state of the driver.
[Solution] The work vehicle comprises a vehicle body capable of traveling with either manual steering using a steering wheel or automatic steering of the steering wheel, which steers the direction of travel to match a planned traveling line parallel to a traveling reference line, a connecting section provided on the vehicle body and to which a work device can be attached, a steering changeover switch that switches between starting and ending the automatic steering, a seating detection device that detects when the driver is seated in the driver's seat, a control device that controls the automatic steering, and an alarm device that alerts when the driver has left the seat, and when automatic steering is being performed, the control device issues an alert using the alarm device if the seating detection device changes from a seating detection state in which it detects a person sitting in the seat to a seat-abandoned detection state in which it does not detect a person sitting in the seat, and stops the automatic steering and stops driving the prime mover when the progression of the seat-abandoned detection state exceeds a predetermined judgment threshold.
[Selected Figure] Figure 1

Description

The present invention relates, for example, to a work vehicle.

Conventionally, the agricultural work machine disclosed in Patent Document 1 is known. The agricultural work machine in Patent Document 1 is equipped with a traveling body that can freely switch between manual traveling by manual steering and automatic traveling by automatic steering along a set traveling line that is set parallel to a reference traveling line, and a changeover switch that can freely switch between manual traveling and automatic traveling. In addition, 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.

JP 2017-123803 A

In the agricultural machine of Patent Document 1, automatic driving can be easily performed by switching from manual driving to automatic driving using a selector switch. The driver's intention must be reflected when starting and ending automatic driving, and stable steering must be performed in response to the driver's requests even during automatic driving. In addition, the driver is required to perform automatic driving in an appropriate state, and it is desirable for the driver to be in an appropriate state when starting and ending automatic driving.

In view of the above problems, the present invention aims to provide a work vehicle that can perform automatic steering appropriately according to the driver's condition.

The technical means of the present invention to solve this technical problem are characterized as follows:

The work vehicle comprises a driver's seat, a steering wheel, a registration switch capable of setting a start point and an end point, a vehicle body capable of traveling either by manual steering using the steering wheel or automatic steering of the steering wheel that steers the direction of travel so as to match a planned traveling line that is parallel to a traveling reference line set based on the start point and the end point, a coupling section provided on the vehicle body and capable of mounting a work device, a prime mover provided on the vehicle body, a traveling device that travels the vehicle body using the power of the prime mover, a positioning device capable of detecting the position of the vehicle body, and a switch that switches the start and end of the automatic steering. The vehicle is equipped with a steering changeover switch that switches between the driver's seat and the driver's seat, a seating detection device that detects when the driver is seated in the driver's seat, a control device that controls the automatic steering, and an alarm device that issues an alarm when the driver leaves the driver's seat. When the automatic steering is being performed and the seating detection device changes from a seating detection state in which the seating is detected to a seat-abandoned detection state in which the seating is not detected, the control device issues the alarm using the alarm device, and when the progress of the seat-abandoned detection state exceeds a predetermined judgment threshold, the control device stops the automatic steering and stops driving the prime mover.

The alarm device increases the intensity of the alarm as the absence detection state continues for a longer period.

When the predetermined judgment threshold is exceeded, it means when the predetermined judgment time is exceeded.

According to the present invention, automatic steering can be stopped appropriately depending on the driver's condition.

FIG. 2 is a diagram showing the configuration and control block diagram of a tractor. FIG. 2 is an explanatory diagram for explaining automatic steering. FIG. 11 is an explanatory diagram for explaining a correction amount in a push switch. FIG. 11 is an explanatory diagram for explaining a correction amount in a slide switch. 4A and 4B are diagrams illustrating a first correction unit and a second correction unit in the push switch. 11A and 11B are diagrams illustrating a first correction unit and a second correction unit in a slide switch. This shows the state when the calculated vehicle body position is shifted to the right while driving straight under automatic steering. This shows the state when the calculated vehicle body position is shifted to the left while driving straight under automatic steering. This is a view of the cover in front of the driver's seat as seen from the driver's seat side. FIG. 2 is an explanatory diagram for explaining automatic steering. FIG. 4 is an operational flow showing the relationship between the seating state and automatic steering. 11 is an explanatory diagram illustrating an elapsed time T1 of the absence detection state and a notification. FIG. FIG. 13 is a diagram showing an operation flow for stopping manual steering as well. 4 is an operational flow showing the relationship between the speed doubling device and automatic steering. 4 is an operational flow showing the relationship between the auto-up device and automatic steering. FIG.

The following describes an embodiment of the present invention with reference to the drawings.

Figure 13 is a side view showing one embodiment of the work vehicle 1, and Figure 13 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 a tractor, 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.

In the following description, the front side of the driver seated in the driver's seat 10 of the tractor (work vehicle) 1 (in the direction of the arrow A1 in FIG. 13) will be referred to as the front, the rear side of the driver (in the direction of the arrow A2 in FIG. 13) 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 addition, the horizontal direction that is perpendicular to the fore-and-aft direction of the work vehicle 1 will be referred to as the vehicle body width direction.

As shown in FIG. 13, the tractor 1 includes a body 3, a prime mover 4, and a transmission 5. The body 3 has a running device 7 and is capable of running. The running 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.

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 can change the propulsive force of the traveling device 7 by changing the speed, and can also switch the traveling device 7 between forward and reverse. The vehicle body 3 is provided with a driver's seat 10.

A coupling section including a lifting device 8 is provided at the rear of the vehicle body 3. A working device can be attached and detached to the coupling section. By connecting the working device to the coupling section, the working device can be towed by the vehicle body 3. The working devices include a tilling device for tilling, a fertilizer spreading device for spreading fertilizer, a pesticide spreading device for spreading pesticide, a harvesting device for harvesting, a reaping device for reaping grass, etc., a spreading device for spreading grass, etc., a grass collecting device for collecting grass, etc., a shaping device for shaping grass, etc., etc.

As shown in FIG. 1, the transmission 5 includes a main shaft (drive shaft) 5a, a main speed change section 5b, a sub-speed change section 5c, a shuttle section 5d, a PTO power transmission section 5e, and a front speed change section 5f. The drive shaft 5a is rotatably supported in a housing case (transmission case) of the transmission 5, and power is transmitted to the drive shaft 5a from the crankshaft of the engine 4. The main speed change section 5b has multiple gears and a shifter that changes the connection of the gears. The main speed change section 5b changes and outputs (shifts) the rotation input from the drive shaft 5a by appropriately changing the connection (meshing) of the multiple gears with the shifter.

The sub-transmission unit 5c, like the main transmission unit 5b, has multiple gears and a shifter that changes 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 multiple gears with the shifter.

The shuttle section 5d has a shuttle shaft 12 and a forward/reverse switching section 13. Power output from the sub-transmission section 5c is transmitted to the shuttle shaft 12 via gears or the like. The forward/reverse switching section 13 is composed of, for example, a hydraulic clutch, and switches the rotation direction of the shuttle shaft 12, i.e., the forward and reverse 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 the rear axle 21R to which the rear wheels 7R are attached.

The PTO power transmission unit 5e has a PTO propulsion shaft 14 and a PTO clutch 15. The PTO propulsion shaft 14 is supported so as to be freely rotatable, and power from the propulsion shaft 5a can be transmitted. The PTO propulsion shaft 14 is connected to the PTO shaft 16 via gears or the like. The PTO clutch 15 is composed of, for example, a hydraulic clutch, and by switching the hydraulic clutch on and off, the state is switched between transmitting the power of the propulsion shaft 5a to the PTO propulsion shaft 14 and not transmitting the power of the propulsion shaft 5a to the PTO propulsion shaft 14.

The front transmission section 5f has a first clutch 17 and a second clutch 18. The first clutch 17 and the second clutch can transmit power from the drive shaft 5a, 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 the front transmission shaft 22. Specifically, the front transmission shaft 22 is connected to the 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.

The first clutch 17 and the second clutch 18 are composed of hydraulic clutches or the like. An oil passage is connected to the first clutch 17, and the oil passage 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 passage is connected to the second clutch 18, and the oil passage 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 an engaged state and a disengaged state by energizing or deenergizing the solenoid of the solenoid valve.

When the first clutch 17 is in a disengaged state and the second clutch 18 is in an engaged state, the power of the shuttle shaft 12 is transmitted to the front wheels 7F through the second clutch 18. As a result, the front and rear wheels are driven by power in a four-wheel drive (4WD) state, and the rotation 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 in an engaged state and the second clutch 18 is in a disengaged state, the vehicle is in a four-wheel drive state, and the rotation speed of the front wheels is faster than that of the rear wheels (4WD speed increase state). Also, when the first clutch 17 and the second clutch 18 are in a disengaged state, the power of the shuttle shaft 12 is not transmitted to the front wheels 7F, and the vehicle is in a two-wheel drive (2WD) state, in which the rear wheels are driven by power.

As shown in FIG. 8, the lifting device 8 has a lift arm 8a, a lower link 8b, a top link 8c, a lift rod 8d, and a lift cylinder 8e. The front end of the lift arm 8a is supported on the upper rear part of the case (transmission case) that houses the transmission 5 so that it can swing upward or downward. The lift arm 8a swings (lifts and lowers) when driven by the lift cylinder 8e. The lift cylinder 8e is composed of a hydraulic cylinder. The lift cylinder 8e is connected to a hydraulic pump via a control valve 29. The control valve 29 is an electromagnetic valve or the like, and extends and retracts the lift cylinder 8e.

The front end of the lower link 8b is supported on the rear lower part of the transmission 5 so that it can swing upward or downward. The front end of the top link 8c is supported on the rear part of the transmission 5 above the lower link 8b so that it can swing upward or downward. The lift rod 8d connects the lift arm 8a to the lower link 8b. The work device 2 is connected to the rear part of the lower link 8b and the rear part of the top link 8c. When the lift cylinder 8e is driven (extends and retracts), the lift arm 8a rises and lowers, and the lower link 8b connected to the lift arm 8a via the lift rod 8d rises and lowers. As a result, the work device 2 swings upward or downward (rises and falls) with the front part of the lower link 8b as a fulcrum.

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, Hokuto, Galileo, and Michibiki. That is, the positioning device 40 receives satellite signals (position of the positioning satellite, transmission time, correction information, etc.) transmitted from the positioning satellite, and detects the position (e.g., latitude and longitude) based on the satellite signal. The positioning device 40 has a receiving device 41 and an inertial measurement unit (IMU) 42. The receiving device 41 is a device that has an antenna and receives satellite signals transmitted from the positioning satellite, and is attached to the vehicle body 3 separately from the inertial measurement unit 42. In this embodiment, the receiving device 41 is attached to a ROPS provided on the vehicle body 3. Note that the mounting location of the receiving device 41 is not limited to the embodiment.

The inertial measurement unit 42 has an acceleration sensor that detects acceleration, a gyro sensor that detects angular velocity, and the like. It is provided on the vehicle body 3, for example, below the driver's seat 10, and the inertial measurement unit 42 can detect the roll angle, pitch angle, yaw angle, and the like of the vehicle body 3.

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 the driver's operation, and automatic steering, in which the vehicle body 3 is steered automatically without the driver's operation.

The steering device 11 has a steering handle (steering wheel) 30 and a steering shaft (rotating shaft) 31 that rotatably supports the steering handle 30. The steering device 11 also has an auxiliary mechanism (power steering device) 32. The auxiliary mechanism 32 assists the rotation of the steering shaft 31 (steering handle 30) by hydraulic pressure or the like. The auxiliary 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 operated by the control valve 34. The control valve 34 is, for example, a three-position switching valve that can be switched by the movement of 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.

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 change in response to 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 vehicle body 3 can change its traveling direction to the left or right by manually steering the steering wheel 30.

Next, we will explain automatic steering.

As shown in FIG. 2, when performing automatic steering, a driving reference line L1 is first set before performing automatic steering. 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 coincides with the planned driving line L2.

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 switch 52 provided on the tractor 1 at the predetermined position (S2), the body position measured by the positioning device 40 is set to the start point P10 of the driving reference line L1 (S3). In addition, the tractor 1 (body 3) is moved from the start point P10 of the driving reference line L1 (S4), and when the driver operates the steering switch 52 at the predetermined position (S5), the body position measured by the positioning device 40 is set to the end point P11 of the driving reference line L1 (S6). Therefore, the straight line connecting the start point P10 and the end point P11 is set as the driving reference line L1.

After the travel reference line L1 is set (after S6), for example, the tractor 1 (body 3) is moved to a location different from the location where the travel reference line L1 was set (S7), and when the driver operates the steering changeover switch 52 (S8), a travel planned line L2, which is a straight line parallel to the travel reference line L1, is set (S9). After the travel planned line L2 is set, automatic steering is started, and the traveling direction of the tractor 1 (body 3) is changed to follow the travel planned line L2. For example, if the current vehicle position is on the left side of the travel planned line L2, the front wheels 7F are steered to the right, and if the current vehicle position is on the right side of the travel planned line L2, the front wheels 7F are steered to the left. 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 the accelerator member (accelerator pedal, accelerator lever) provided on the tractor 1 or by changing the gear stage of the transmission.

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

As shown in FIG. 1, the steering device 11 has an automatic steering mechanism 37.
Reference numeral 37 denotes a mechanism for automatically steering 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 whose rotation direction, rotation speed, rotation angle, etc. can be controlled based on the vehicle body position. The gear mechanism 39 includes a gear provided on the steering shaft 31 and rotating together with the steering shaft 31, and a gear provided on the rotation shaft of the steering motor 38 and rotating 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 planned travel line L2.

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 the 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 settings are made at least before the start of automatic steering. 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 and end points of the driving reference line L1 are set.

The setting switch 51 can be switched ON or OFF. When it is ON, it outputs a signal indicating that the setting mode is active, and when it is OFF, it outputs a signal indicating that the setting mode is inactive. When it is ON, the setting switch 51 outputs a signal indicating that the setting mode is active to the display device 45, and when it is OFF, it outputs a signal indicating that the setting mode is inactive to the display device 45.

The tractor 1 is equipped with a steering changeover switch 52. The steering changeover switch 52 is a switch that switches the start or end of automatic steering. Specifically, the steering changeover switch 52 can be switched from the neutral position to up, down, forward, or backward, and outputs the start of automatic steering when switched from the neutral position to down while the setting mode is active, and outputs the end of automatic steering when switched from the neutral position to up while the setting mode is active. In addition, when the steering changeover switch 52 is switched from the neutral position to backward while the setting mode is active, it outputs that the current vehicle position is set to the start point P10 of the driving reference line L1, and when the steering changeover switch 52 is switched from the neutral position to forward while the setting mode is active, it outputs that the current vehicle position is set 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.

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 (called the calculated vehicle body position) calculated using the satellite signal (position of the positioning satellite, transmission time, correction information, etc.) and the measurement information (acceleration, angular velocity) measured by the inertial measurement unit 42.

The correction switch 53 is configured as a push switch that can be pressed or a slide switch that can be slid. Below, we will explain the cases where the correction switch 53 is a push switch and a slide switch.

When the correction switch 53 is a push switch, the amount of correction is set based on the number of times the push switch is operated. The amount of correction is determined by the formula: correction amount = number of times of operation x correction amount per one operation. For example, as shown in Fig. 3A, the amount of correction 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 amount of correction based on the number of times the push switch is operated.

In addition, when 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 correction amount = the displacement amount from a predetermined position. For example, as shown in FIG. 3B, the correction amount increases by several centimeters or several tens of centimeters every time the displacement amount of the slide switch increases by 5 mm. The operation amount (displacement amount) of the slide switch is input to the first control device 60A, and the first control device 60A sets (calculates) the correction amount based on the displacement amount. Note that the method of increasing the correction amount and the rate of increase described above are not limited to the numerical values described above.

More specifically, as shown in Figures 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 or OFF switches that are automatically restored each time they are operated. The switch constituting the first correction unit 53A and the switch constituting the second correction unit 53B are integrated. 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 (left correction amount) corresponding to the left side of the vehicle body 3 increases. Also, each time the second correction unit 53B is pressed, the correction amount (right correction amount) corresponding to the right side of the vehicle body 3 increases.

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 long hole. When the correction switch 53 is a slide switch, the first correction unit 53A and the second correction unit 53B are arranged 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. Also, 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.

Next, we will explain the relationship between the correction amount (left correction amount, right correction amount) by the correction switch 53, the planned driving line L2, and the behavior (driving trajectory) of the tractor 1 (body 3).

FIG. 5A shows a state in which the calculated vehicle body position W1 is shifted to the right while moving straight during automatic steering. As shown in FIG. 5A, when automatic steering is started, if the actual position (actual position W2) of the tractor 1 (vehicle body 3) coincides with the calculated vehicle body position W1, and the actual position W2 coincides with the planned travel line L2, the tractor 1 travels along the planned travel line L2. That is, in the section P1 in which the positioning device 40 has no error in its positioning 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 travel line L2. Note that, when the positioning device 40 has no error in its positioning and no correction is performed, the calculated vehicle body position W1 and the vehicle body position (corrected vehicle body position) W3 corrected by the correction amount are the same value. The corrected vehicle body position W3 is the corrected vehicle body position W3 = calculated vehicle body position W1 - correction amount.

Here, in the vicinity of position P20, even though the actual position W2 is not deviated from the planned driving line L2, an error occurs in the positioning of the positioning device 40 due to various influences, and the vehicle body position W1 detected by the positioning device 40 deviates to the right from the planned driving line L2 (actual position W2), and if the deviation amount W4 is maintained, the tractor 1 determines that a deviation has occurred between the calculated vehicle body position W1 and the planned driving line L2, and steers the tractor 1 to the left so as to eliminate the deviation amount W4 between the calculated vehicle body position W1 and the planned driving line L2. Then, the actual position W2 of the tractor 1 is shifted to the planned driving line L2 by steering to the left. After that, the driver notices that the tractor 1 is deviated from the planned driving line L2, and steers the 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 by 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 of the planned 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 planned travel line L2.

Figure 5B shows the state when the calculated vehicle body position W1 is shifted to the left while driving 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 match, and the actual position W2 and the planned driving line L2 match, the tractor 1 will travel along the planned driving line L2, as in Figure 5A. That is, as in Figure 5A, in section P2 where there is no error in the positioning of the positioning device 40, the tractor 1 will travel along the planned driving line L2. Also, as in Figure 5A, the calculated vehicle body position W1 and the corrected vehicle body position W3 are the same value.

Here, at position P22, due to various influences, an error occurs in the positioning of the positioning device 40, and the vehicle body position W1 detected by the positioning device 40 is shifted to the left with respect to the actual position W2, and if the shift amount W5 is maintained, the tractor 1 steers the tractor 1 to the right so as to eliminate the shift amount W5 between the calculated vehicle body position W1 and the planned driving line L2. Then, suppose that the driver notices that the tractor 1 is shifted from the planned driving line L2, and the driver 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 approximately the same as the actual position W2. In other words, by setting the left correction amount by the first correction unit 53A, the vehicle body position of the positioning device 40 can be corrected in a direction that eliminates the shift amount W5 that occurred near position P22. As shown in position P23 in FIG. 5B, if the actual position W2 of the tractor 1 is away to the right of the planned driving line L2 after the vehicle position is corrected, the tractor 1 is steered to the left, and the actual position W2 of the tractor 1 can be aligned with the planned driving line L2.

Next, we will explain the setting switch 51 and correction switch 53.

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.

The panel cover 178 supports the display device 45. The 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 an attachment surface 178f to which the setting switch 51 and the correction switch 53 are attached. The attachment surface 178f is provided behind the support portion 178e and below the steering handle 30. The support portion 178e and the attachment surface 178f are continuous, with the support portion 178e located in front of the upper plate portion 178a and the attachment surface 178f located in the rear of the upper plate portion 178a. The setting switch 51 and the correction switch 53 are attached to the attachment surface 178f. As a result, the setting switch 51 and the correction switch 53 are arranged around the steering shaft 31.

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 switching unit 13 is placed in 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 switching unit 13 is placed in 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.

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 tube 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 column cover 179. Therefore, the setting switch 51 and the correction switch 53 attached to the mounting surface 178f are disposed around the column cover 179.

Next, the locations of the setting switch 51, steering changeover switch 52, and correction switch 53 will be described in detail. 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 composed of 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.

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, the distance between the correction switch 53 and the steering wheel 30 can be secured long. This makes it possible to more reliably prevent unintentional operation of the correction switch 53 and steering of the steering wheel 30.

As described above, the setting switch 51, the steering changeover switch 52, and the correction switch 53 are arranged around the steering shaft 31. In other words, the setting switch 51, the steering changeover switch 52, and the correction switch 53 are concentrated around the steering shaft 31. Therefore, the driver can clearly understand the position 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. Therefore, operability is improved and erroneous operation can be prevented. In addition, the harness (wiring) arranged from each switch can be shortened.

The above-mentioned switch arrangement may be reversed between left and right. That is, one side may be the left and the other side the right, or one side may be the right and the other side the left. Specifically, for example, the setting switch 51 and 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.

As shown in FIG. 1, the tractor 1 is equipped with multiple control devices 60. The multiple control devices 60 are devices that control the travel system, the work system, calculate the vehicle body position, and the like in the tractor 1. The multiple 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 the satellite signal (received information) received by the receiving device 41 and the measurement information (acceleration, angular velocity, etc.) measured by the inertial measurement device 42, and determines the vehicle body position based on the received information and the measurement information. For example, when the correction amount by the correction switch 53 is zero, that is, when the correction of the vehicle body position by the correction switch 53 is not commanded, the first control device 60A does not perform correction on 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, when the correction of the vehicle body position by the correction switch 53 is commanded, the first control device 60A sets the correction amount of the vehicle body position based on either the number of times the correction switch 53 is operated or the amount of operation (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.

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 planned driving 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 drives along the planned driving line L2.

7, when the deviation between the vehicle body position and the planned driving line L2 is less than a 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 driving line L2 is equal to or greater than the threshold value and the tractor 1 is located to the left of the planned driving 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 to the right. When the deviation between the vehicle body position and the planned driving line L2 is equal to or greater than the threshold value and the tractor 1 is located to the right of the planned driving 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 to the left. In the above 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 travel direction (travel direction) of the tractor 1 (vehicle body 3) are different, 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). The automatic steering control unit 200 may also 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 orientation (orientation deviation). The setting of the steering angle in automatic steering in the above embodiment is an example and is not limited.

As described above, the control device 60 can automatically steer the tractor 1 (body 3).

The third control device 60C performs various controls related to the tractor 1. The third control device 60C can perform manual lift control, auto-up control, double speed control, etc. In the manual lift control, the lift device 8 is raised and lowered based on the operation of the lift switch 101 connected to the third control device 60C. Specifically, the lift switch 101 is provided around the driver's seat 10 and is a three-position switch. When the lift switch 101 is switched from the neutral position to one side, an up signal that raises the lift device 8 (lift arm 8a) is input to the third control device 60C. Also, when the lift switch 101 is switched from the neutral position to the other side, a down signal that lowers the lift device 8 (lift arm 8a) is input to the third control device 60. When the third control device 60C receives an up signal, it outputs a control signal to the control valve 29 to raise the lift device 8, and when it receives a down signal, it outputs a control signal to the control valve 29 to lower the lift device 8. In other words, the third control device 60 can perform manual lift control to raise and lower the lift device 8 in response to manual operation of the lift switch 101.

In addition, the auto-up control is a control in which the lifting device 8 is automatically operated to raise the working device 2 when the tractor 1 (body 3) moves backward. Specifically, a reverse detection device 102 that detects reverse is connected to the control device 60 such as the control device 60C. The reverse detection device 102 is a sensor that detects the rotation of the front axle 21F, a sensor that detects the rotation of the rear axle 21R, a sensor that detects the switching position of the shuttle lever 181, etc. That is, the reverse detection device 102 detects the reverse of the tractor 1 (body 3) when the rotation direction of the front axle 21F and the rotation direction of the rear axle 21R are the rotation direction corresponding to reverse, and when the switching position of the shuttle lever 181 is on the reverse side. When the reverse detection device 102 detects the reverse of the tractor 1 (body 3), the third control device 60C performs auto-up control to automatically raise the lifting device 8 by outputting a control signal to the control valve 29. Note that the reverse motion detection device 102 described above is only one example and is not limiting.

In addition, in the double speed control, when the steering angle of the steering device 11 is equal to or greater than a predetermined value, for example, a steering angle corresponding to a turn, the connection of the first clutch 17 and the second clutch 18 is automatically changed to make the rotation speed of the front wheels 7F faster than the rotation speed of the rear wheels. Specifically, a steering angle detection device 205 that detects the steering angle of the steering device 11 is connected to a control device 60 such as the control device 60C. When the steering angle detected by the steering angle detection device 205 is equal to or greater than the steering angle corresponding to a turn, the control device 60C outputs control signals to the first operating valve 25 and the second operating valve 26 to connect the first clutch 17 and disconnect the second clutch 18, thereby making the rotation speed of the front wheels 7F faster than the rotation speed of the rear wheels.

As described above, the control device 60C can perform controls related to the tractor 1, such as manual lift control, auto-up control, and double speed control.

As mentioned above, automatic steering can be performed by switching the steering changeover switch 52, but the tractor 1 changes the control related to automatic steering depending on the seating status of the operator (driver) in the driver's seat 10.

A seating detection device 110 is connected to the control device 60 such as the control device 60B. The seating detection device 110 is a device capable of detecting that the driver is seated in the driver's seat 10. The seating detection device 110 is, for example, a load sensor provided in the seat portion 10a or the backrest portion 10b of the driver's seat 10. When the seating detection device 110 is a load sensor provided in the seat portion 10a, if the load applied to the seat portion 10a is equal to or greater than a predetermined value (above a threshold value), the control device 60 determines that the driver is seated in the driver's seat 10, whereas if the load applied to the seat portion 10a is less than the threshold value, the control device 60 determines that the driver is not seated in the driver's seat 10.

Alternatively, even if the seating detection device 110 is a load sensor provided in the backrest 10b, if the load applied to the backrest 10b is equal to or greater than a predetermined value (above a threshold value), the control device 60B determines that the driver is seated in the driver's seat 10, whereas if the load applied to the backrest 10b is less than the threshold value, it determines that the driver is not seated in the driver's seat 10. Note that, although the seating detection device 110 is configured as a load sensor in the above-described embodiment, it is not limited to this and may be anything that can detect seating in the driver's seat 10.

Figure 9 is an operational flow showing the relationship between seating position and automatic steering.

When the setting mode is enabled by the setting switch 51 in a situation where the start position (start point P10) and the end position (end point P11) have not been set (S21, Yes), the second control device 60B monitors the detection status of the seating detection device 110. When the seating detection device 110 detects a person sitting (S22, Yes) and the steering switch 52 is operated to set the start point (operation from the neutral position to the rearward) (S23, Yes), the current vehicle position is set to the start point P10 of the driving reference line L1 (S24: start point registration). Note that the second control device 60B does not set the start point P10 even if the start point is operated in a situation where the seating detection device 110 has not detected a person sitting. If the driver is not sitting in the driver's seat 10 at the time of registering the start point, the display device 45 displays a message encouraging the driver to sit down.

In addition, when the seating detection device 110 detects a person sitting in the seat (S22, Yes) and the steering switch 52 is operated to set the end point (from the neutral position to the forward position) (S25, Yes), the current vehicle body position is set to the end point P11 of the driving reference line L1 (S26: End point registration). Note that the second control device 60B does not set the end point P11 even if the end point is operated when the seating detection device 110 does not detect a person sitting in the seat. In addition, if the driver is not sitting in the driver's seat 10 at the time of registering the end point, the display device 45 displays a message encouraging the driver to sit down.

Therefore, when the driver is seated in the driver's seat 10, the start point P10 and end point 11 of the driving reference line L1 can be set.

After setting the start point P10 and end point P11 of the driving reference line L1, if the steering changeover switch 52 switches to start automatic steering (S27, Yes), the second control device 60B determines whether the seating detection device 110 detects a seated person, and if a seated person is detected (S28, Yes), permits automatic steering (S29). When automatic steering is permitted, the second control device 60B sets the planned driving line L2 parallel to the driving reference line L1, and executes automatic steering as described above (S30).

On the other hand, if the seating detection device 110 does not detect a person being seated (S28, No), the second control device 60B does not permit automatic steering, that is, does not permit automatic steering even if the steering changeover switch 52 switches to start automatic steering (S31). Note that if automatic steering is not permitted, the display device 45 displays a message encouraging the person to be seated.

The second control device 60B monitors the detection status of the seating detection device 110 even during automatic steering (S32). If, during automatic steering, the seating detection device 110 changes from a seating detection state in which it detects a seating occupancy to a departure detection state in which it does not detect a seating occupancy (S33, Yes), the second control device 60B stops (ends) the automatic steering (S34: automatic steering stopped). When automatic steering is stopped, the second control device 60B switches from automatic steering to manual steering, for example, by stopping the output of a control signal to the steering motor 38.

In addition, when the second control device 60B changes from the seating detection state to the absence detection state, as shown in FIG. 10, the automatic steering may be stopped when the elapsed time of the absence detection state (the elapsed time since the seating detection state ended) T1 exceeds a predetermined threshold (determination time). In this case, when the absence state occurs, it is preferable to notify the driver that the driver has left the driver's seat 10 by the notification device 80. Specifically, the notification device 80 is connected to the control device 60 such as the second control device 60B. The notification device 80 is a speaker, a lamp, etc., and is provided near the driver's seat 10. As shown in FIG. 10, the notification device 80 starts notification (ON) at the time P25 when the absence state occurs, and notifies the driver that the driver has left the driver's seat 10 by voice output from the speaker, warning sound, lighting or blinking of the lamp, etc. As the time that has passed since the person left the desk increases, the notification device 80 increases the duration of the audio output and the warning sound output, decreases the flashing rate of the lamp, increases the brightness of the lamp, and increases the intensity of the notification.

As described above, the second control device 60B permits automatic steering when the seating detection device 110 detects a person seated and the steering changeover switch 52 has switched on the start of automatic steering, and does not permit automatic steering when the seating detection device 110 does not detect a person seated and the steering changeover switch 52 has switched on the start of automatic steering. Therefore, automatic steering can be started by operating the steering changeover switch 52 with the driver reliably seated in the driver's seat 10.

When automatic steering is being performed, the second control device 60B stops (ends) automatic steering if the seating detection device 110 changes from a seating detection state in which it detects a person sitting to a leaving detection state in which it does not detect a person sitting. Therefore, automatic steering can be stopped at the point when the driver leaves the driver's seat 10 during automatic steering.

In the embodiment described above, the second control device 60B stops automatic steering when the seat detection state changes from the seat occupancy detection state to the seat absence detection state, but in addition to this, manual steering may also be stopped. Figure 11 shows an operation flow for stopping manual steering as well. In Figure 11, S21 to S33 are the same as in Figure 9.

As shown in FIG. 11, when the state changes from seated detection state to unseated detection state (S33, Yes), the second control device 60B stops driving the prime mover 4 (S35: Stop prime mover). That is, the second control device 60B stops the prime mover 4 by turning off the ignition or outputting a signal to stop the drive of the prime mover 4 to a control device that controls the drive of the prime mover 4. When the prime mover 4 stops, power from the prime mover 4 is no longer transmitted to the traveling device 7, so the tractor 1 (body 3) can be stopped.

The work vehicle 1 is equipped with a driver's seat 10, a steering wheel 30, a vehicle body 3 that can be driven by either manual steering using the steering wheel 30 or automatic steering of the steering wheel 30 based on a driving reference line, a steering changeover switch 52 that switches between starting and ending automatic steering, a seating detection device 110 that detects that the driver is seated in the driver's seat 10, and a control device 60 (second control device 60B) that allows automatic steering when the seating detection device 110 detects that the driver is seated and the start of automatic steering is switched by the steering changeover switch 52, and does not allow automatic steering when the seating detection device 110 does not detect that the driver is seated and the start of automatic steering is switched by the steering changeover switch 52. According to this, when the driver is securely seated in the driver's seat 10, when the driver operates the steering changeover switch 52 to switch the start of automatic steering, automatic steering can be started. In other words, automatic steering can be performed appropriately according to the driver's state.

When automatic steering is being performed, the control device 60 (second control device 60B) stops automatic steering if the seating detection device 110 changes from a seating detection state in which it detects a person seated to a leaving detection state in which it does not detect a person seated. This makes it possible to automatically switch from automatic steering to manual steering if the driver leaves the driver's seat 10 during automatic steering.

The work vehicle 1 includes a prime mover 4 provided on the vehicle body 3 and a driving device 7 that drives the vehicle body 3 using the power of the prime mover 4. The control device 60 (second control device 60B) stops driving the prime mover 4 when the driver changes from a seated detection state to an unseated detection state. This makes it possible to stop both automatic steering and manual steering when the driver leaves the driver's seat 10, and also to stop the work vehicle 1.

The work vehicle 1 is equipped with a positioning device 40 capable of detecting the position of the vehicle body 3, and a reference line setting switch that sets the position of the vehicle body 3 detected by the positioning device 40 as the start and end positions of the driving reference line L1. This makes it possible to easily set the start and end positions of the driving reference line L1 by operating the reference line setting switch.

The work vehicle 1 is equipped with a correction switch 53 that issues a command to correct the position of the vehicle body 3 detected by the positioning device 40, and a steering device 11 that steers the vehicle body 3 based on a corrected vehicle body position (corrected position) W3, which is the position of the vehicle body 3 corrected by operating the correction switch 53, and a planned driving line L2 that is set based on a driving reference line L1. This makes it possible to make the vehicle body 3 travel along the planned driving line L2 by the steering device 11 while correcting the position of the vehicle body 3 by operating the correction switch 53.

Now, the third control device 60C of the tractor 1 can limit the operation of the operating device provided on the tractor 1 when automatic steering is being performed under the control of the second control device 60B. In other words, when automatic steering is being performed under the control of the second control device 60B, the third control device 60C limits control such as auto-up control and double speed control.

The third control device 60C operates the actuator when predetermined operating conditions are met when automatic steering is not being performed (when manual steering is being performed), but does not operate the actuator when the operating conditions are met when automatic steering is being performed.

The restrictions on the operation of the actuator are explained in detail below.

The operating device is, for example, a speed doubling device or an auto-up device. The speed doubling device is a device that makes the rotational speed of the front wheels 7F faster than the rotational speed of the rear wheels 7R by speed doubling control in the third control device 60C, with the operating condition being that the steering angle of the steering wheel 30 is equal to or greater than a predetermined value (equal to or greater than the steering angle corresponding to a turn). In this embodiment, the speed doubling device includes a first clutch 17, a second clutch 18, a first operating valve 25, and a second operating valve 26.

The auto-up device is a device that raises the lifting device 8 when the vehicle body 3 moves backward. In this embodiment, the auto-up device includes a lift cylinder 8e and a control valve 29.

Figure 12A is an operational flow showing the relationship between the speed doubling device and automatic steering when the operating device is a speed doubling device. Note that the tractor 1 is provided with a changeover switch that switches the speed doubling control between enabled and disabled, and the operational flow of Figure 12A will be explained on the assumption that the speed doubling control is enabled by the changeover switch.

After setting the start position (start point P10) and end position (end point P11) of the driving reference line L1, when automatic steering is not being performed, i.e., when the steering changeover switch 52 has not commanded the start of automatic steering (S40, No), the second control device 60B outputs stop information indicating that automatic steering is stopped to the third control device 60C (S41). On the other hand, when the third control device 60C acquires the stop information (S42), it monitors the steering angle detected by the steering angle detection device 205 (S43). When the steering angle detected by the steering angle detection device 205 is equal to or greater than a predetermined value (S44, Yes), the third control device 60C outputs control signals to the first operating valve 25 and the second operating valve 26 to make the rotation speed of the front wheels 7F faster than the rotation speed of the rear wheels 7R (S45).

When the steering changeover switch 52 issues a command to start automatic steering (S40, Yes), the second control device 60B outputs operation information indicating that automatic steering is being operated to the third control device 60C (S46). When the third control device 60C acquires the operation information (S47), it sets the double speed control from enabled to disabled (S48), and does not perform double speed control even if the steering angle detected by the steering angle detection device 205 is equal to or greater than a predetermined value. The third control device 60C also waits until it acquires stop information indicating that automatic steering has been stopped (ended) from the second control device 60B (S49).

Next, when the steering changeover switch 52 commands the end of automatic steering (S50), the second control device 60B outputs stop information to the third control device 60C (S51). When the third control device 60C acquires the stop information (S49, Yes), it switches the double speed control from disabled to enabled (S52), returns to S43, and executes the double speed control.

In other words, the third control device 60C starts the operation of the speed multiplier when the operating conditions are met when automatic steering is not being performed, and does not start the operation of the speed multiplier when automatic steering is being performed and the operating conditions are met.

Figure 12B is an operational flow showing the relationship between the auto-up device and automatic steering when the operating device is an auto-up device. Note that the tractor 1 is provided with a changeover switch that switches the auto-up control between enabled and disabled, and the explanation of the operational flow in Figure 12B will proceed on the assumption that the auto-up control is enabled by the changeover switch.

After setting the start position (start point P10) and end position (end point P11) of the driving reference line L1, when automatic steering is not being performed, i.e., when the steering changeover switch 52 has not commanded the start of automatic steering (S60, No), the second control device 60B outputs stop information to the third control device 60C (S61). On the other hand, when the third control device 60C acquires the stop information (S62), it determines whether the vehicle body 3 is moving backwards based on the detection information from the reverse detection device 102, and if the vehicle body 3 is moving backwards (S63, Yes), it outputs a control signal to the control valve 29 to automatically raise and lower the lifting device 8 (S64).

When the steering changeover switch 52 issues a command to start automatic steering (S60, Yes), the second control unit 60B outputs operation information to the third control unit 60C (S65). When the third control unit 60C acquires the operation information (S66), it sets the auto-up control from enabled to disabled (S67), and does not perform the auto-up control even if the reverse detection device 102 detects reverse motion. The third control unit 60C also waits until it acquires stop information transmitted from the second control unit 60B (S68).

Next, when the steering changeover switch 52 commands the end of automatic steering (S69), the second control unit 60B outputs stop information to the third control unit 60C (S70). When the third control unit 60C acquires the stop information (S68, Yes), it switches the double speed control from disabled to enabled (S71), returns to S63, and executes the auto-up control.

In other words, the third control device 60C starts the operation of the auto-up device when the operating conditions are met when automatic steering is not being performed, and does not start the operation of the auto-up device when automatic steering is being performed and the operating conditions are met.

The work vehicle 1 is equipped with a steering wheel 30, a vehicle body 3 capable of traveling by either manual steering using the steering wheel 30 or automatic steering of the steering wheel 30 based on a traveling reference line L1, an actuation device provided on the vehicle body 3, and a control device 60 (third control device 60C) that limits the actuation of the actuation device when automatic steering is being performed. With this, the actuation of the actuation device can be limited when automatic steering is performed, so that the effect of the actuation device on the automatic steering can be reduced, and automatic steering can be performed smoothly.

The control device 60 (third control device 60C) activates the actuating device when predetermined operating conditions for the actuation of the actuating device are met when automatic steering is not being performed, and does not operate the actuating device when the operating conditions are met when automatic steering is being performed. This allows automatic steering to be prioritized over the operation of the actuating device when the operating conditions are met.

The work vehicle 1 is equipped with a running gear including front and rear wheels, and the operating device is a speed-doubling device that makes the rotational speed of the front wheels faster than the rotational speed of the rear wheels when the steering angle of the steering wheel 30 is equal to or greater than a predetermined value, and the control device 60 (third control device 60C) starts operation of the speed-doubling device when the operating condition is met when automatic steering is not being performed, and does not start operation of the speed-doubling device when automatic steering is being performed and the operating condition is met. According to this, when automatic steering is performed, the steering angle can be made equal to or greater than the predetermined value at which the speed-doubling device operates, and more accurate automatic steering can be performed even when a speed-doubling device is present.

The work vehicle 1 is equipped with a working device provided at the rear of the vehicle body 3 and a lifting device that raises and lowers the working device, and the operating device is an auto-up device that raises the lifting device when the vehicle body 3 moves in reverse as an operating condition, and the control device 60 (third control device 60C) starts the operation of the auto-up device when the operating condition is met in a state where automatic steering is not performed, and does not start the operation of the auto-up device when the operating condition is met in a state where automatic steering is performed. This allows automatic steering not only to be performed when the vehicle body 3 moves forward, but also when the vehicle body 3 moves in reverse.

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

REFERENCE SIGNS LIST 1 work vehicle 3 vehicle body 4 prime mover 10 driver's seat 11 steering device 30 steering handle 40 positioning device 52 steering changeover switch 53 correction switch 60 control device 60B second control device 60C third control device 101 lift switch 102 reverse motion detection device 110 seating detection device 205 steering angle detection device L1 travel reference line L2 planned travel line

Claims (3)

The driver's seat and
A steering handle and
A registration switch capable of setting a start point and an end point;
a vehicle body capable of traveling by either manual steering using the steering wheel or automatic steering of the steering wheel that steers a traveling direction so as to match a planned traveling line that is parallel to a traveling reference line that is set based on the starting point and the ending point;
A connection portion provided on the vehicle body and capable of mounting a working device;
A prime mover provided on the vehicle body;
a traveling device that causes the vehicle body to travel using the power of the prime mover;
a positioning device capable of detecting the position of the vehicle body;
A steering changeover switch that switches between starting and ending the automatic steering;
a seating detection device for detecting when a driver is seated in the driver's seat;
A control device for controlling the automatic steering;
An alarm device that notifies the driver that the driver is away from the driver's seat;
Equipped with
The control device of this work vehicle, when the automatic steering is being performed and the seating detection device changes from a seating detection state in which the seating is detected to an absence detection state in which the seating is not detected, issues the alert through the alarm device, and when the progression of the absence detection state exceeds a predetermined judgment threshold, stops the automatic steering and stops driving the prime mover. The work vehicle according to claim 1, wherein the alarm device increases the intensity of the alarm as the absence detection state continues for a longer period of time. The work vehicle according to claim 1 or 2, wherein the predetermined judgment threshold is exceeded when a predetermined judgment time is exceeded.

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