TWI825346B - Work vehicle - Google Patents

Abstract

Conventional work vehicles such as rice transplanters cannot perform turning control of the vehicle body. The work vehicle of the present invention includes: a steering member driving device (44) that drives the steering member (52); a control device (200) that controls the steering member driving device (44); and a detection mechanism that is configured to detect the turning state related to the vehicle body (10). The control device (200) performs turning control when turning the vehicle body (10), and the control device (200) performs turning state determination based on the result of the detection, and determines to control the steering turning angle based on the the turning state.

Description

work vehicle

The invention relates to a work vehicle such as a rice transplanter traveling in farmland.

There is known a rice transplanter that has: a planting device that can be mounted on a vehicle body to be lifted and lowered; a steering motor that drives a steering handle; and a control device that operates by causing the steering motor to drive the steering handle. Straight travel control and turning control of the vehicle body (for example, see Patent Document 1).

[Prior technical literature]

[Patent Document]

[Patent Document 1] Japanese Patent Application Publication No. 2008-92818.

However, since the turning control accuracy of the vehicle body of the conventional work vehicle such as the rice transplanter mentioned above is low, it is impossible to perform continuous travel to the next process with straight travel control with high accuracy.

An object of the present invention is to provide a work vehicle capable of controlling the turning of the vehicle body in consideration of the above-mentioned conventional problems.

Solution 1 of the present invention is a work vehicle, equipped with: a steering member driving device (44) for driving the steering member (52); a control device (200) for controlling the aforementioned steering member driving device (44); and a detection mechanism. Detection related to the turning state of the vehicle body (10) is performed, the control device (200) performs turning control when the vehicle body (10) is made to turn, and the control device (200) determines the turning state based on the result of the detection. , and the steering maneuver angle is controlled based on the aforementioned maneuver state determination.

A second aspect of the present invention is the work vehicle according to the first aspect of the present invention, wherein in order to make the turning vehicle body (10) go straight again, the control device (200) changes the return direction based on the turning state determination. The steering swing angle return time of the swing angle is used to control the aforementioned steering swing angle.

A third aspect of the present invention is the work vehicle according to the second aspect of the present invention, wherein the steering swing angle return timing can be adjusted based on manual operation to adjust a predetermined steering swing angle return level.

The fourth invention is a work vehicle as in the first invention, wherein the control device (200) maintains the steering swing angle at a constant angle until after the swing state determination time when the swing state determination is made, based on the swing state Determine to change the aforementioned constant angle, thereby controlling the aforementioned steering maneuver angle.

Aspect 5 of the present invention is a work vehicle as described in any one of aspects 1 to 4 of the present invention, wherein the detection mechanism is provided with a rear wheel speed sensor (210) and a positioning system (300), as the maneuver starts , the measurement of the traveling distance is started by the aforementioned rear wheel speed sensor (210). When the orientation of the aforementioned vehicle body (10) reaches a predetermined angle, if the aforementioned traveling distance is long, the aforementioned positioning system (300) It is determined that the swing is a large swing. If the driving distance is small, the positioning system (300) determines that the swing is a small swing.

Aspect 6 of the present invention is a work vehicle as described in any one of aspects 1 to 4 of the present invention, wherein the detection mechanism is provided with a rear wheel speed sensor (210) and a positioning system (300), as the maneuver starts , the measurement of the traveling distance is started by the aforementioned rear wheel speed sensor (210). When the aforementioned traveling distance reaches a predetermined distance, if the orientation change of the aforementioned vehicle body (10) from the beginning of the revolution is small, the aforementioned positioning system (300) determines that the rotation is a large rotation. If the orientation of the vehicle body (10) changes greatly from the start of the rotation, the positioning system (300) determines that the rotation is a small rotation.

According to the first aspect of the present invention, it is possible to control the turning of the vehicle body.

According to the aspect 2 of the present invention, in addition to the effects of the aspect 1 of the present invention, highly precise control can be achieved.

According to the third aspect of the present invention, in addition to the effects of the second aspect of the present invention, highly flexible control can be realized.

According to the fourth aspect of the present invention, in addition to the effects of the first aspect of the present invention, highly precise control can be achieved.

According to the fifth aspect of the present invention, in addition to the effects of any one of the first to fourth aspects of the present invention, when it is determined that a large slalom is to occur, the steering is controlled so that the body comes inside. When turning, the steering is controlled so that the body comes to the outside, thereby improving turning accuracy.

According to the sixth aspect of the present invention, in addition to the effects of any one of the first to fourth aspects of the present invention, when it is judged that a large pirouette has become, the steering is controlled so that the body comes inside, and when it is judged that the pirouette has become a small pirouette, the steering is controlled. Down, the steering is controlled so that the body comes to the outside, thereby improving the turning accuracy.

10:Car body

20:Engine

30:Travel device

31:Front wheel

32:Rear wheel

33:auxiliary wheels

41: Main transmission mechanism

42: Auxiliary transmission mechanism

43:Rear wheel gearbox

44: Control motor (steering member drive device)

50: Driving unit

51: Seat

52: Control handle (steering member)

53:Main gear lever

54: Auxiliary gear lever

55: Straight travel auxiliary lever

56: Auxiliary mode switch

60:Soil preparation device

61:Soil preparation rotor mechanism

62: Floating mechanism for land preparation

70: Fertilizer device

80:Scribe

90: Lifting device for planting equipment

100:Planting device

101: Preparing the seedling platform

200:Control device

210: Rear wheel speed sensor

220: Planting device lifting sensor

300: Positioning system

400: Threshold adjustment device

A:arrow

C0, C1, C2: Swirl trajectory

Lh: planting start line

Lh0: imaginary line

Lv, Lv0: straight line

P0,P1,P2,Q1,Q2: position

Ps: Swing start position

S1,S2,S3,S4,S5: location

Z: straight ahead control transition area

θ0: Orientation

[Fig. 1] is a perspective view of the rice transplanter according to the embodiment of the present invention.

[Fig. 2] is a block diagram of the power transmission system of the rice transplanter according to the embodiment of the present invention.

[Fig. 3] is a block diagram of the control system of the rice transplanter according to the embodiment of the present invention.

[Fig. 4] It is an explanatory diagram (Part 1) of the rotation control of the rice transplanter according to the embodiment of the present invention.

[Fig. 5] It is an enlarged explanatory diagram of the rotation control of the rice transplanter according to the embodiment of the present invention.

[Fig. 6] It is an explanatory diagram of the reverse turning control of the rice transplanter according to the embodiment of the present invention.

[Fig. 7] is a partial perspective view of the rice transplanter according to the embodiment of the present invention.

[Fig. 8] It is a partial top view of the rice transplanter according to the embodiment of the present invention.

[Fig. 9] It is an enlarged partial plan view of the vicinity of the auxiliary wheel of the rice transplanter according to the embodiment of the present invention.

Embodiments of the present invention will be described in detail with reference to the drawings.

The same is true below, but some components may not be shown in the drawings, and may be shown in perspective or omitted.

The rice transplanter of this embodiment is an example of the work vehicle in this invention or invention related to this invention.

In a modified embodiment, for example, the work vehicle in the present invention or an invention related to the present invention may be an agricultural tractor.

The operating handle (52) is an example of a steering member in the present invention or an invention related to the present invention. The steering motor (44) is an example of a steering member driving device that drives the steering handle (52) in the present invention or an invention related to the present invention.

The control device (200) is an example of a control device that controls the steering motor (44) in the present invention or an invention related to the present invention.

The vehicle body (10) is an example of the vehicle body in the present invention or inventions related to the present invention. The rear wheel speed sensor (210) and the positioning system (300) are examples of detection mechanisms for detecting the turning state of the vehicle body (10) in the present invention or inventions related to the present invention.

The auxiliary wheel (33) is an example of a single or a plurality of auxiliary wheels mounted on at least one of the inner and outer sides of the vehicle body (10) in the left-right direction of the vehicle body (10) in the present invention or an invention related to the present invention.

The rear wheel (32) on the inside of the swing is an example of a predetermined wheel in the present invention or inventions related to the present invention.

First, the structure and operation|movement of the rice transplanter of this embodiment are demonstrated concretely, referring FIG.1 and FIG.2.

Here, FIG. 1 is a perspective view of the rice transplanter according to the embodiment of the present invention, and FIG. 2 is a block diagram of the power transmission system of the rice transplanter according to the embodiment of the present invention.

While describing the operation of the rice transplanter according to this embodiment, the traveling control method of the invention related to the present invention will also be described.

The rice transplanter of this embodiment is a ride-on mat seedling rice transplanter for eight-row planting. The planting device (100) has four planting units, and each planting unit has a pair of left and right two planting implements.

The rice transplanter is not limited to a ride-on seedling transplanter with eight rows of planting. For example, it may also be a ride-on potted seedling transplanter with ten rows of planting.

First, the basic structure and operation of the rice transplanter of this embodiment are demonstrated. Therefore, the spin control and the like will be described in detail later.

The driving unit (50) has a seat (51) provided above the engine (20).

An operating handle (52) for operating the front wheel (31) is provided in front of the seat (51). Moreover, horizontal step floors are provided on the left and right sides of the engine (20). Furthermore, a preliminary seedling loading platform (101) is provided on the vehicle body (10).

The traveling device (30) is a device that drives the vehicle body (10) using the front wheels (31) and the rear wheels (32).

The land preparation device (60) is a device that uses a land preparation rotor mechanism (61) and a land preparation floating mechanism (62) to prepare farmland.

The marker (80) that forms a straight line mark toward the farmland as the target of the next planting travel route is stowably mounted on the vehicle body (10).

The planting device (100) is installed on the rear side of the vehicle body (10) via the planting device lifting device (90).

The rotational power system of the engine (20) mounted on the main frame is transmitted to the main transmission mechanism (41) which is a HST (Hydro Static Transmission; hydraulic stepless transmission) mechanism and the like. The main transmission mechanism (41) and the auxiliary transmission mechanism (42) separate the rotated power after the transmission into the traveling power used in the traveling device (30) and the like, and the external take-out power used in the planting device (100) and the like. motivation.

Part of the driving power is transmitted to the left and right front wheel end cases to drive a pair of left and right front wheels (31), and the remaining driving power is transmitted to the left and right rear wheel gearboxes (43) to drive a pair of left and right rear wheels (32). Furthermore, part of the traveling power transmitted to the rear wheel gearbox (43) is transmitted to the soil preparation device (60) and the fertilizing device (70).

Next, the structure and operation of the rice transplanter of this embodiment are demonstrated more specifically, referring mainly to FIG. 1 to FIG. 3.

Here, FIG. 3 is a block diagram of the control system of the rice transplanter according to the embodiment of the present invention.

The control device (200) not only performs lever operations of the main gear lever (53), the auxiliary gear lever (54) or the straight-travel auxiliary lever (55) and the switch operation of the auxiliary mode switch (56), but also uses rear wheel speed sensing. A device that performs various controls based on the detection results of the device (210) or the lifting sensor (220) of the planting device.

The positioning system (300), for example, uses the typical GNSS (Global Navigation Satellite System; Global Navigation Satellite System), that is, GPS (Global Positioning System; Global Positioning System), through DGPS (Differential Global Positioning System; Differential Global Positioning System) technology. A system for positioning.

In driving control, since the size of the vehicle body (10), the responsiveness of the control motor (44), the state of the farmland, etc. must be comprehensively considered, the positioning performed by the positioning system (300) is extremely accurate even temporarily. , it is also difficult to achieve precise driving control, so various attempts have been made.

In the straight travel control, the positioning system (300) that obtains the current orientation information of the vehicle body (10) is used to register in advance the coordinates of point A corresponding to the starting point of the straight travel for planting work and the end point of the straight travel. The corresponding coordinates of point B. Furthermore, the steering motor (44) is driven to perform steering so as to perform straight travel based on an imaginary line connecting point A and point B, thereby achieving straight travel control.

However, since each turn requiring manual steering requires an on/off operation of the straight travel control, the burden on the operator is not reduced, and the operability and workability are not necessarily sufficient.

Therefore, it is desired to realize not only straight control but also rotation control that automatically performs row alignment of the distance between planting rows. Therefore, basic rotation control such as the following is considered.

Of course, it goes without saying that the spin control method described below can be used in various spin controls. Specifically, one of the above various types of turning control is, for example, a turning control that does not include a straight motion during turning, the steering angle is kept substantially constant during turning, and the turning path of the vehicle body (10) is a substantially semicircular path.

((A1)) Next, the structure and operation of the rice transplanter of this embodiment are demonstrated more specifically, referring mainly to FIG. 4 and FIG. 5.

Here, FIG. 4 is an explanatory diagram (Part 1) of the rotation control of the rice transplanter according to the embodiment of the present invention, and FIG. 5 is an enlarged explanatory diagram of the rotation control of the rice transplanter according to the embodiment of the present invention.

The rice transplanter of this embodiment is a rice transplanter in which the control device (200) performs turning control when turning the vehicle body (10) traveling straight.

The control device (200) determines the turning state based on the detection result, and controls the steering angle based on the determination of the turning state.

For example, in the automatic turning control of a rice transplanter, the control of turning is performed while maintaining a fixed steering turning angle at a constant α (for example, 45 degrees) in a manner that does not include a straight movement during turning. . In the control of setting a turning path using GPS and turning along the path, control may be difficult and unstable. In addition, if the vehicle is turned while turning, the rotation of the rear wheel on the inside of the turn will change, which is called a Z-turn or other control instability. By setting the control swing angle to be constant, control is easy and the versatility is greater for various types of aircraft. Since the steering angle of the maneuver is constant, the rotation of the inside rear wheel of the maneuver is stable, and it is possible to easily determine whether the rotation of the inside rear wheel is small and the rotation is large without adding a sensor or the like.

In order to make the turned vehicle body (10) go straight again, the control device (200) controls the steering turn angle by changing the steering turn angle return timing based on the turning state determination.

The steering maneuver angle return timing is a time when the difference between the orientation of the turned vehicle body (10) and the orientation of the vehicle body (10) to go straight again is lower than a predetermined steering maneuver angle return level.

For example, the steering return angle is 30 degrees.

The steering swing angle return timing can be adjusted based on manual operation to adjust a predetermined steering swing angle return level.

For example, the steering angle return level may be reduced to 25 degrees or increased to 35 degrees by dial operation of the threshold adjustment device (400) based on the operator's experience.

The time at which the turning state is determined is based on the position of the arrow (A) determined by the orientation such as the body orientation or the body's orthogonal orientation, distance, time, GNSS position, vehicle speed, etc. The turning state is determined based on orientation, distance, time, GNSS position or vehicle speed.

For example, when there is a difference between the orientation of the turned vehicle body (10) and the orientation of the vehicle body (10) to go straight again, that is, when the vehicle body orientation is at a position of 45 degrees, it is possible to have time to spare. Determination of the size of the gyration trajectory.

When it is determined that the turning trajectory of the vehicle body (10) starting from the turning starting position (Ps) on the straight line (Lv0) which is the previous process line is a standard-sized turning trajectory (C0), the steering turning angle is not performed. When the return time is changed, the steering maneuver angle returns to the horizontal position (P0) at the standard steering maneuver angle of 30 degrees. Even if the steering swing angle return timing is not changed, the vehicle body (10) can enter the straight ahead control transition zone (Z) as it reaches the virtual line (Lh0) in front of the planting start line (Lh). The vehicle body (10) automatically moves straight again along the straight line (Lv), making a smooth transition to straight control.

The transition from the turning control to the straight travel control is performed, for example, at a time when entry into the straight travel control transition zone (Z) is recognized based on the GNSS position.

In order to make a smooth transition to the straight travel control, it is preferable to realize not only the entry angle to the straight travel line (Lv) but also the steering in front of the straight travel control transition area (Z) as the straight travel line (Lv) that is the next process line approaches. The turning angle is not very large either.

The inventor of the present invention changes the steering maneuver angle return timing based on the maneuver state determination, thereby ensuring a smooth transition to this type of straight ahead control regardless of the maneuver state that is easily affected by farmland conditions and the like.

Specifically, based on the determination of the size of the turning trajectory, the steering turning angle return timing can be changed in the following manner.

When it is determined that the turning trajectory is a small turning trajectory (C1), the steering turning angle is returned to the horizontal position (Q1) at, for example, a steering turning angle of 35 degrees larger than 30 degrees, instead of the standard 30 degrees. The steering angle returns to the horizontal position (P1) at the moment. In this way, even if the turning trajectory is a small turning trajectory (C1), the vehicle body (10) can travel close to the straight line (Lv) and enter the straight traveling control transition zone (Z). Therefore, the smooth transition to straight traveling control is also performed. Transition.

When it is determined that the turning trajectory is a large turning trajectory (C2), the steering turning angle is returned to the horizontal position (Q2) at, for example, a steering turning angle of 25 degrees smaller than 30 degrees, instead of the standard 30 degrees. It returns to the horizontal position (P2) at the moment when the steering angle of rotation is 10 degrees. In this way, even if the turning trajectory is a large turning trajectory (C2), the vehicle body (10) can enter the straight-travel control transition zone (Z) without traveling far from the straight-travel line (Lv). Therefore, the smooth control to straight-travel can be performed in the same manner. transition.

Of course, although the steering angle return timing can also be changed based on the orientation, it can also be changed based on distance, time, GNSS position, vehicle speed, etc., in order to correct the movement path for a smooth transition to straight ahead control. .

In addition, in the turning assist correction control using the rear wheel pulse wave, in order to know the rear wheel rotation speed used to determine the size of the turning trajectory, the turning inside rear wheel pulse wave during the turning is measured from the beginning of the automatic turning control. The pulse wave number on the inside of the rear wheel during automatic turning has little influence on slippage, etc., so it can be judged whether the turning operation is normal.

In the automatic turning control of the rice transplanter, the pulse wave number of the turning inner rear wheel is measured from the start of the automatic turning control until the body orientation reaches a predetermined orientation (θ0). (θ0) is set to 45 degrees or less superior. Based on the rear wheel pulse wave number at the time point of the body orientation (θ0), a judgment is made whether to add correction to the automatic turning control. If (θ0) is 45 degrees or less, even if correction is added to the automatic swing control, there is a risk that the control will be too late and the swing accuracy will deteriorate.

When the pulse wave number at this time is p1 to p2, it is determined that the maneuver is performed normally, and the correction control is not performed. By setting the width p1 to p2 to an appropriate value for the rear wheel pulse wave on the inner side of the swing in the automatic swing control, the swing accuracy can be improved without adding unnecessary correction control.

When the pulse wave number p is p≧p2, it is judged that the gyration has become a large gyration, and the steering is controlled to delay the return to the starting position and move the body inward so that the planting alignment can be started. When it is determined that a large swing has occurred based on the rear wheel rotation speed, the turning accuracy can be improved by controlling the steering return to the starting position so that the body comes inside to align the start of planting.

When the pulse wave number p is p≦p1, the maneuver is judged to be a small maneuver, and the control is controlled to delay the steering return to the starting position and move the body to the outside in advance so that the planting alignment can be started. When it is determined from the rotation speed of the rear wheel that a small maneuver has occurred, the steering is controlled to return to the starting position so that the body comes to the outside and the start of planting can be aligned, thereby improving the precision of the maneuver.

Although the size of the turning trajectory can be determined in this way based on the magnitude of the rear wheel rotation speed when the body orientation reaches the position of a predetermined angle, it can also be determined conversely based on the body orientation at the time when the rear wheel rotation speed reaches the predetermined number of times. to determine the size of the gyration trajectory. For example, when the size of the body orientation at the time when the rear wheel rotation speed reaches a predetermined number of times is small, it may be determined that the maneuver has become a large spin, and control may be performed to delay the steering return to the starting orientation and move the body inward. to start planting alignment.

The final result is based on a single or multiple physical quantities selected from orientation, distance, time, GNSS position or vehicle speed to determine the moment when the turning state is determined. Although the turning state can also be determined based on the same physical quantities, the combination of these physical quantities The system is arbitrary. For example, the time to determine the turning state may be determined based on the distance and the GNSS position, and the turning state may be determined based on the orientation and vehicle speed.

In addition, although the steering maneuver angle return time can be changed based on a single or multiple physical quantities selected from orientation, distance, time, GNSS position, vehicle speed, etc., the steering maneuver angle return time change, etc., is based on the steering maneuver angle. The combination of the controlled physical quantity and the aforementioned physical quantity can be determined independently or dependently. For example, the time to determine the turning state may be determined based on time, the turning state determination may be determined based on the vehicle speed, and the steering turning angle return time may be changed based on the orientation and GNSS position.

The control device (200) may control the steering maneuver angle by maintaining the steering maneuver angle at a constant angle until the maneuver state determination time when the maneuver state is determined, and then changing the constant angle based on the maneuver state determination.

When the pulse wave number p is p≧p2, it is determined that the turning is a large turning, and the steering turning angle α, which is a constant angle, is controlled so that the deflection increases and the small turning is performed. When it is determined from the rotation speed of the rear wheel that a large spin is in progress, the steering control is performed to achieve a small spin, thereby improving the turning accuracy.

When the pulse wave number p is p≦p1, it is determined that the turning is a small turning, and the steering turning angle α, which is a constant angle, is controlled so that the deflection returns to a large turning. When it is determined from the rotation speed of the rear wheel that a small spin is achieved, the steering control is performed to achieve a large spin, thereby improving the turning accuracy.

Changes to a constant angle such as deflection increase or deflection return of the steering angle α may be performed simultaneously with the determination of the steering state. It goes without saying that, for example, the change may be performed 0.2 seconds after the determination of the steering state.

In order to make the turned vehicle body (10) go straight again, the control device (200) may control the steering turn angle by changing the steering turn angle return speed to return the steering turn angle based on the turning state determination.

Of course, the change of the steering swing angle return speed may replace the change of the steering swing angle return timing, or may be performed simultaneously with the change of the steering swing angle return timing, so that the movement path can be corrected smoothly. For example, the body orientation for returning the steering swing angle may be constant, or only the steering swing angle return speed may be changed.

It goes without saying that the return of the steering maneuver angle may be performed simultaneously with the determination of the maneuvering state. For example, the return of the steering maneuver angle may be performed 0.2 seconds after the determination of the maneuvering state.

In a structure in which the steering maneuver angle return speed can be adjusted, even if the time when the steering state is determined is very close to the steering maneuver angle return time, the steering maneuver angle return speed can be increased without delay.

(A2) Next, the structure and operation of the rice transplanter of this embodiment are demonstrated more specifically with reference mainly to FIG. 6.

Here, FIG. 6 is an explanatory diagram of reverse turning control of the rice transplanter according to the embodiment of the present invention.

The rice transplanter of this embodiment is a rice transplanter in which the control device (200) performs turning control when the vehicle body (10) that is traveling straight stops, moves backward, stops again, and then turns.

After backing up from the point (S1) and going straight to the point (S2), a turn is performed automatically or semi-automatically from the point (S2) to the point (S5) via the point (S3) and the point (S4).

Of course, in the case of automatic control HST modes such as hole planting control and hole approach control among the swing control, a configuration in which the swing assist control is not started is also considered. This is because if the spin assist is started due to mistakenly approaching the hole, the HST may behave unexpectedly. Therefore, it is desirable to prevent unexpected HST actions.

The rice transplanter of this embodiment is a rice transplanter in which the control device (200) performs straight-running control before turning when the vehicle body (10) is driven straight, and performs turning control when the vehicle body (10) is turned straight. The control is to perform straight-forward control after turning when the turning vehicle body (10) is made to go straight again.

Switching from straight control before turning to turning control is performed by manual operation.

Of course, switching from the straight travel control before turning to the turning control is the same as the switching from the turning control to the straight traveling control after turning around. It is considered that both the embodiment is performed automatically, and the switching from the turning control to the straight traveling after turning around is also considered based on manual operation. Example of controlled switching.

In order to make the turned vehicle body (10) go straight again, the steering turning angle return time is set to a time before the straight heading control start time of the straight heading control after starting the turning.

The steering maneuver angle return timing is a time when the difference between the orientation of the turned vehicle body (10) and the orientation of the vehicle body (10) to go straight again is lower than a predetermined steering maneuver angle return level.

As mentioned above, for example, the steering return angle is 30 degrees.

The steering swing angle return timing can be adjusted based on manual operation to adjust a predetermined steering swing angle return level.

As described above, for example, the steering angle return level may be reduced to 25 degrees or increased to 35 degrees by dial operation of the threshold adjustment device (400) based on the operator's experience.

[Industrial Availability]

The work vehicle in the present invention can control the turning of the vehicle body, and is useful for use in work vehicles such as rice transplanters.

10:Car body

A:arrow

C0, C1, C2: Swirl trajectory

Lh: planting start line

Lh0: imaginary line

Lv, Lv0: straight line

P0: position

Ps: Swing start position

Z: straight ahead control transition area

Claims (5)

A work vehicle is provided with: a steering member driving device (44) for driving the steering member (52); a control device (200) for controlling the steering member driving device (44); and a detection mechanism for communicating with the vehicle body (10 ) detection related to the turning state; the control device (200) performs turning control when the vehicle body (10) is made to turn; the control device (200) determines the turning state based on the result of the detection, and based on the turning state Determine to control the steering swing angle; in order to make the turning vehicle body (10) go straight again, the aforementioned control device (200) changes the steering swing angle return time based on the aforementioned turning state determination to return to the aforementioned steering swing angle, thereby controlling The aforementioned steering maneuver angle; the aforementioned steering maneuver angle return timing can be adjusted based on manual operation to adjust a predetermined steering maneuver angle return level. A work vehicle is provided with: a steering member driving device (44) for driving the steering member (52); a control device (200) for controlling the steering member driving device (44); and a detection mechanism for communicating with the vehicle body (10 ) detection related to the turning state; the control device (200) performs turning control when the vehicle body (10) is made to turn; the control device (200) determines the turning state based on the result of the detection, and based on the turning state Determine to control the steering angle; The control device (200) maintains the steering maneuver angle at a constant angle until after the maneuver state determination time when the maneuver state determination is performed, and then changes the constant angle based on the maneuver state determination, thereby controlling the steering maneuver angle. A work vehicle is provided with: a steering member driving device (44) for driving the steering member (52); a control device (200) for controlling the steering member driving device (44); and a detection mechanism for communicating with the vehicle body (10 ) detection related to the turning state; the control device (200) performs turning control when the vehicle body (10) is made to turn; the control device (200) determines the turning state based on the result of the detection, and based on the turning state Determine to control the steering swing angle; a rear wheel speed sensor (210) and a positioning system (300) are provided in the aforementioned detection mechanism. As the swing begins, the measurement of the traveling distance is started by the aforementioned rear wheel speed sensor (210). When the orientation of the vehicle body (10) reaches a predetermined angle, if the traveling distance is long, the positioning system (300) determines that the swing has become a large gyration. (300) is judged to be a small convolution. A work vehicle is provided with: a steering member driving device (44) for driving the steering member (52); a control device (200) for controlling the steering member driving device (44); and a detection mechanism for communicating with the vehicle body (10 ) detection related to the turning state; the control device (200) performs turning control when the vehicle body (10) is made to turn; the control device (200) determines the turning state based on the result of the detection, and based on the turning state Determine to control the steering angle; The detection mechanism is provided with a rear wheel speed sensor (210) and a positioning system (300). As the maneuver begins, the measurement of the traveling distance is started by the rear wheel speed sensor (210). When the travel distance reaches a predetermined distance When, if the change in the orientation of the aforementioned vehicle body (10) from the start of the revolution is small, the aforementioned positioning system (300) determines that the revolution has become a large revolution. If the change in the orientation of the aforementioned vehicle body (10) from the start of the revolution is large, Then it is determined by the aforementioned positioning system (300) that the gyration is a small gyration. The work vehicle according to any one of claims 2 to 4, wherein in order to make the turning vehicle body (10) go straight again, the control device (200) changes the return steering turning angle based on the turning state determination. The steering swing angle returns at the moment to control the aforementioned steering swing angle.

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