Patent Description:
A working vehicle is known from <CIT>. Another working vehicle is known from <CIT>, as well as <CIT> and <CIT>. Further, the working vehicle disclosed in <CIT> is known.

The working vehicle disclosed in <CIT> has a traveling vehicle (a tractor) to autonomously travel along a target traveling route, and a working device to be mounted on the traveling vehicle.

In the working vehicle disclosed in document <CIT>, the traveling vehicle can autonomously travel along a target traveling route. However, since the target traveling route is created on premise that a center of the traveling vehicle in a width direction thereof matches a center of the working device in a width direction thereof, this causes a problem that a work trace of the working device is offset relative to the target traveling route in a vehicle width direction when the working device is offset relative to the traveling vehicle in the vehicle width direction.

In view of the above-mentioned problem, the present invention intends to provide a working vehicle configured to prevent a work trace of a working device from being offset relative to a target traveling route in a vehicle width direction even when the working device is offset relative to a traveling vehicle.

A working vehicle according to one aspect of the present invention, includes a traveling vehicle configured to autonomously travel on a target traveling route, a working device attached to the traveling vehicle, an offset acquisition unit to acquire an offset amount and an offset direction in a vehicle width direction between a width directional center of the traveling vehicle and a predetermined point in the working device, and a traveling position corrector to correct, based on the offset amount and the offset direction acquired by the offset acquisition unit, a traveling position of the traveling vehicle so that the predetermined point is located on the target traveling route. When, in the vehicle width direction, a width directional center of the working device matches a center in a working width of the working device, the offset acquisition unit acquires the offset amount and the offset direction based on the width directional center directional center of the working device serving as the predetermined point; and
when, in the vehicle width direction, the width directional center of the working device does not match the center in the working width of the working device, the offset acquisition unit acquires the offset amount and the offset direction based on the center in the working width of the working device serving as the predetermined point.

In addition, the working vehicle can comprise: an autonomous traveling controller to control autonomous traveling of the traveling vehicle so that the predetermined point matches the target traveling route in the vehicle width direction, wherein, when the offset direction matches a displacement direction of the target traveling route from the predetermined point the traveling position corrector outputs, to the autonomous traveling controller, a control signal to move the traveling vehicle by the offset amount in the same direction as the offset di-rection; and when the offset direction is opposite to the displacement direction of the target traveling route from the predetermined point, the traveling position corrector outputs, to the autonomous traveling controller, a control signal to move the traveling vehicle by the offset amount in a direction opposite to the offset direction.

In addition, the working vehicle includes a display device configured to display an offset amount input portion to which the offset amount is input, and an offset direction input portion to which the offset direction is input. The offset acquisition unit acquires the offset amount input to the offset amount input portion and the offset direction input to the offset direction input portion.

In addition, the working vehicle includes an attaching unit provided on a rear portion of the traveling vehicle and configured to have the working device attached thereto, and a detector to detect a change in position of the attaching unit in the vehicle width direction relative to a reference position that is a position of the attaching unit at which the width directional center of the traveling vehicle matches the predetermined point in the vehicle width direction. The offset acquisition unit acquires the offset amount and the offset direction based on the change detected by the detector.

In addition, the attaching unit is constituted of a three-point linkage mechanism having a lower linkage, a top linkage, and a lift rod, the working device is connected to at least the lower linkage. The detector includes a sensor to detect the change when a position of the lower linkage changes from the reference position.

In addition, the sensor is an angle sensor or a stroke sensor.

According to the above-mentioned working vehicle, a traveling position of the traveling vehicle can be corrected by the traveling position corrector so that the predetermined point is located on the target traveling route based on the offset amount and the offset direction of the predetermined point in the working device acquired by the offset acquisition unit. Accordingly, even in a case where the working device is offset in the vehicle width direction from the traveling vehicle, a work trace of the working device will not be offset in the vehicle width direction from the target traveling route.

With reference to the drawings, an embodiment of the present invention will be described below.

<FIG> shows a side view of a working vehicle <NUM> according to an embodiment.

The working vehicle <NUM> includes a traveling vehicle <NUM> and a working device <NUM>. The traveling vehicle <NUM> is a tractor in the embodiment. In the following description, the tractor <NUM> is explained as the traveling vehicle <NUM>. However, the traveling vehicle <NUM> is not limited to the tractor.

As shown in <FIG>, the tractor <NUM> includes a vehicle body <NUM>, a traveling device <NUM>, and a lifting device <NUM>. In the following description, a forward direction (a direction indicated by an arrowed line A1 in <FIG>) of a driver sitting on a driver seat <NUM> of the tractor <NUM> is referred to as the front, a rearward direction (a direction indicated by an arrowed line A2 in <FIG>) of the operator is referred to as the rear, a leftward direction of the operator is referred to as the left, and a rightward direction of the operator is referred to as the right. In addition, a horizontal direction orthogonal to a fore-and-aft direction of the tractor <NUM> is referred to as a vehicle width direction.

A center in the vehicle width direction is also referred to as a "center in width direction".

The vehicle body <NUM> has a vehicle frame <NUM>, a clutch housing <NUM>, and a transmission case <NUM>. The vehicle frame <NUM> extends in a fore-and-aft direction of the vehicle body <NUM>.

A prime mover <NUM> is mounted on the vehicle frame <NUM>. In the embodiment, the prime mover <NUM> is an engine <NUM>. The clutch housing <NUM> is continuously connected to a rear portion of the engine <NUM> and houses a clutch. The transmission case <NUM> is connected to a rear portion of the clutch housing <NUM> and houses a transmission device, a rear wheel differential, and the like. The transmission device includes a main transmission device and a sub transmission device. The transmission device is capable of switching a magnitude of propulsive force of the traveling device <NUM> through gear shift, and is also capable of switching a traveling direction of the traveling device <NUM> between forward and backward. A PTO shaft <NUM> protrudes from a rear portion of the vehicle body <NUM> (rearward from the transmission case <NUM>).

The traveling device <NUM> has front wheels 4F located on a front portion of the vehicle body <NUM> and rear wheels 4R located on the rear portion of the vehicle body <NUM>. The front wheels 4F are supported by the vehicle frame <NUM>. The rear wheels 4R are supported by respective output shafts of the rear wheel differential.

A driver seat <NUM> and a cabin <NUM> surrounding the driver seat <NUM> are mounted on the vehicle body <NUM>. A display device <NUM> is located on the periphery of (right in front of) the driver seat <NUM>.

The display device <NUM> is constituted of, for example, a touch panel liquid crystal display (a liquid crustal monitor).

The lifting device <NUM> is provided on the rear portion of the vehicle body <NUM>. The lifting device <NUM> is an attaching unit for attaching the working device <NUM> to the tractor <NUM>. Hereinafter, the lifting device <NUM> is also referred to as an attaching unit <NUM>. When the working device <NUM> is attached to the attaching unit (lifting device) <NUM>, the working device <NUM> is attached to a rear portion of the tractor <NUM>. This allows the working device <NUM> to be towed by the tractor <NUM>.

The working device <NUM> is a device configured to perform work on a ground surface of an agricultural field or the like. For example, the working device <NUM> is a cultivator for cultivating, a fertilizer sprayer for spraying fertilizer, a pesticide sprayer for spraying pesticides, a harvester for harvesting, a mower for mowing grass and the like, a tedder for diffusing grass and the like, a raking device for collecting grass and the like, or a baler for molding grass and the like. <FIG> shows an example in which the cultivator (a rotary cultivator) is attached as the working device <NUM>.

As shown in <FIG>, the tractor <NUM> has a steering device <NUM>. The steering device <NUM> has a handling wheel (that is, a steering wheel) 13a, a rotation shaft (that is, a steering shaft) 13b that rotates with the rotating of the steering wheel 13a, and an assist mechanism (that is, a power steering mechanism) 13c that assists the steering of the steering wheel 13a. The auxiliary mechanism 13c has a hydraulic pump <NUM>, a control valve <NUM> to which hydraulic fluid output from the hydraulic pump <NUM> is supplied, and a steering cylinder <NUM> to be operated by the control valve <NUM>. The control valve <NUM> is a solenoid valve configured to be operated according to a control signal. For example, the control valve <NUM> is a three-position switching valve configured to be switched through movement of a spool or the like. The control valve <NUM> can also be switched through the steering of the steering shaft 13b. The steering cylinder <NUM> is connected to an arm (that is, a knuckle arm) <NUM> that changes orientations of the front wheels 4F.

Thus, when the steering wheel 13a is operated, a switching position and an opening aperture of the control valve <NUM> are switched according to the operation of the steering wheel 13a, and the steering cylinder <NUM> is extended and contracted rightwardly or leftwardly according to the switching position and the opening aperture of the control valve <NUM>, thereby changing the steering directions of the front wheels 4F. The above-mentioned configuration of the steering device <NUM> is just an example, and a configuration of the steering device <NUM> is not limited to the above-mentioned configuration.

As shown in <FIG>, the attaching unit (that is, the lifting device) <NUM> has lift arms 5a, lower linkages 5b, a top linkage 5c, lift rods 5d, and lift cylinders 5e. Front end portions of the lift arms 5a are supported swingably up and down on a rear portion of the transmission case <NUM> that houses the transmission device. The lift arms 5a are swung (that is, lifted and lowered) through driving of the lift cylinders 5e. The lift cylinders 5e are constituted of hydraulic cylinders. The lift cylinders 5e are connected to a hydraulic pump with a control valve (not shown in the drawings). The control valve (that is, a control valve for the lift cylinders) is a solenoid valve or the like, and extends and contracts the lift cylinders 5e.

Front end portions 5f of the lower linkages 5b are supported swingably up and down on the rear portion of the tractor <NUM>. The front end portion of the top linkage 5c is supported swingably up and down on a rear portion of the transmission case <NUM> above the lower linkages 5b. The lift rods 5d connect the lift arms 5a to the lower linkages 5b. The working device <NUM> is connected to at least the lower linkages 5b. Specifically, the working device <NUM> is connected to rear portions of the lower linkages 5b and a rear portion of the top linkage 5c. When the lift cylinders 5e are driven (extended and contracted), the lift arms 5a are lifted and lowered, and the lower linkages 5b connected to the lift arms 5a with the lift rods 5d are lifted and lowered. This causes the working device <NUM> to be swung up and down (that is, lifted and lowered) with the front end portions 5f of the lower linkages 5b as fulcrums.

The lower linkages 5b are attached to the rear portion of the tractor <NUM>, however some mechanical plays (that is, clearances) are provided in their portions attached to the tractor <NUM>. Thus, the lower linkages 5b are allowed to be swung slightly in the vehicle width direction (leftward or rightward) within the mechanical plays, using the front end portions 5f attached to the rear portion of the tractor <NUM> as fulcrums. The lower linkages 5b are allowed to be swung in this manner, and accordingly the working device <NUM> is also allowed to be swung slightly in the vehicle width direction (leftward or rightward). This prevents an excessive load from being applied to the working device <NUM> during the work.

As shown in <FIG>, the tractor <NUM> has a positioning device <NUM>. The positioning device <NUM> is configured to detect its own position (that is, positioning information including latitude and longitude) with satellite positioning systems (that is, positioning satellites) such as D-GPS, GPS, GLONASS, HOKUTO, GALILEO, and MICHIBIKI. That is, the positioning device <NUM> receives satellite signals (that is, positions of the positioning satellites, transmission times, correction information, and the like) transmitted from the positioning satellite, and detects a position of the tractor <NUM> (for example, latitude, longitude), that is, detects a vehicle position, based on the satellite signals. The positioning device <NUM> is located at a center of the tractor <NUM> in a width direction thereof.

That is, a position of the positioning device <NUM> in the vehicle width direction matches a center of the tractor <NUM> in the width direction thereof.

The positioning device <NUM> has a receiver <NUM> and an inertial measurement unit (IMU) <NUM>. The receiver <NUM> has an antenna and the like to receive satellite signals transmitted from the positioning satellites, and is attached to the tractor <NUM> separately from the inertial measurement unit <NUM>. As shown in <FIG>, in the embodiment, the receiver <NUM> is mounted on an upper portion of a roof 12a of the cabin <NUM> of the tractor <NUM>. An attachment location of the receiver <NUM> is not limited to that of the embodiment. For example, in the tractor <NUM> without the cabin <NUM>, the receiver <NUM> can be attached to an upper portion of the ROPS (Roll-Over Protective Structure) or the like.

The inertial measurement unit <NUM> has an acceleration sensor to detect acceleration, a gyro sensor to detect angular velocity, and the like. The inertial measurement unit <NUM> is located below the tractor <NUM> (for example, below the driver seat <NUM>). The inertial measurement unit <NUM> can detect a roll angle, a pitch angle, a yaw angle, and the like of the tractor <NUM>.

As shown in <FIG>, the steering device <NUM> has an autonomous steering mechanism <NUM>. The autonomous steering mechanism <NUM> is a mechanism configured to autonomously steer the tractor <NUM>. The autonomous steering mechanism <NUM> autonomously steers the tractor <NUM> based on a position of the tractor <NUM> (referred to as a vehicle position) detected by the positioning device <NUM>. The autonomous steering mechanism <NUM> has a steering motor <NUM> and a gear mechanism <NUM>. The steering motor <NUM> is a motor to control a rotational direction, a rotational speed, a rotational angle, and the like based on a vehicle position.

The gear mechanism <NUM> includes a gear located on the rotation shaft (that is, a steering shaft) 13b and configured to rotate with the rotation shaft 13b and another gear located on a rotation shaft of the steering motor <NUM> and configured to rotate with the rotation shaft 13b. When the rotation shaft of the steering motor <NUM> rotates, the rotation is transmitted to the rotation shaft 13b through the gear mechanism <NUM>, and then the rotation shaft 13b rotates. This allows steering directions of the front wheels 4F to be changed, and a vehicle position (a center in the vehicle width direction) to match a target traveling route (referred to as a scheduled traveling route) L1 to be described below.

As shown in <FIG>, the tractor <NUM> has a controller <NUM>. The controller <NUM> controls a traveling system and a work system of the tractor <NUM>.

The controller <NUM> has an autonomous traveling controller <NUM> to control autonomous traveling of the tractor <NUM>. The autonomous traveling controller <NUM> is constituted of electrical and electronic circuits provided in the controller <NUM>, computer programs stored in a CPU, or the like.

A control of autonomous traveling of the tractor <NUM> by the autonomous traveling controller <NUM> will be described below.

<FIG> shows an example of a positional relationship between a target traveling route (that is, a scheduled traveling route) L1, the tractor <NUM>, and the working device <NUM> during autonomous traveling of the tractor <NUM>.

In <FIG>, a point PW1 shows a position of a control target that is to be positioned on the target traveling route L1 (hereinafter referred to as a "control target position PW1"). A point PW2 shows a vehicle position of the tractor <NUM> detected by the positioning device <NUM> (hereinafter referred to as a "detected vehicle position PW2"). Here, the control target position PW1 is positioned at a width directional center W2 of the working device <NUM>, and the detected vehicle position PW2 is positioned at a width directional center W1 of the tractor <NUM>.

A symbol ΔL shows a deviation of the detected vehicle position PW2 from the target traveling route L1 in the vehicle width direction (hereinafter referred to as a "displacement amount"). A symbol ΔW shows a deviation of the control target position PW1 in the vehicle width direction from the detected vehicle position PW2 (hereinafter referred to as an "offset amount"). Hereinafter, the deviation in the left direction may be indicated with a symbol "+" (plus), and the deviation in the right direction may be indicated with a symbol "-" (minus).

The control target position PW1 can be expressed by the following expression; the control target position PW1 = the detected vehicle position PW2 + ΔW. The detected vehicle position PW2 can be expressed by the following expression; the detected vehicle position PW2 = the target traveling route L1 - ΔL. Thus, the control target position PW1 can be expressed by the following expression; the control target position PW1 = L1 + (ΔW - ΔL).

The autonomous traveling controller <NUM> controls the autonomous traveling of the tractor <NUM> so that the deviation (ΔW - ΔL) becomes zero. That is, the autonomous traveling controller <NUM> controls the autonomous traveling of the tractor <NUM> so that the control target position PW1 matches the target traveling route L1 in the vehicle width direction.

A specific control method by the autonomous traveling controller <NUM> will be explained below, however the explanation describes a case where ΔW is zero, that is, a case where the control target position PW1 matches the detected vehicle position PW2 in the vehicle width direction. A case where ΔW is not zero will be described later.

When the autonomous traveling controller <NUM> starts autonomous traveling, the autonomous traveling controller <NUM> controls the steering motor <NUM> of the autonomous steering mechanism <NUM> so that the tractor <NUM> travels at a position where the deviation (ΔW - ΔL) becomes zero (that is, less than a threshold value). In addition, when the autonomous traveling controller <NUM> starts the autonomous traveling, the autonomous traveling controller <NUM> controls a vehicle speed (that is, a velocity) of the tractor <NUM> by autonomously changing gear shifts of the transmission device, a revolving speed of the prime mover, and the like.

As shown in <FIG>, in the autonomous traveling of the tractor <NUM>, when the deviation in the vehicle width direction between the detected vehicle position PW2 from the target traveling route L1 is less than a threshold value (a case where ΔL can be supposed to be zero), the autonomous traveling controller <NUM> maintains a rotation angle of the rotation axis of the steering motor <NUM>. In this case, since ΔW is zero and ΔL is zero, an expression, (ΔW - ΔL) = <NUM>, is satisfied.

As shown in <FIG>, when the deviation ΔL of the detected vehicle position PW2 from the target traveling route L1 is a threshold value or more and the tractor <NUM> is positioned leftward from the target traveling route L1 (in a case where ΔL > <NUM>), the autonomous traveling controller <NUM> rotates the rotation shaft of the steering motor <NUM> so that a steering direction of the tractor <NUM> is orientated to the right. In this case, an expression, (ΔW - ΔL) < <NUM>, is satisfied because ΔW is equal to zero and ΔL is greater than zero. The autonomous traveling controller <NUM> controls autonomous traveling of the tractor <NUM> so that the expression, (ΔW - ΔL), provides zero through rightward steering of the tractor <NUM>.

As shown in <FIG>, when the deviation ΔL of the detected vehicle position PW2 from the target traveling route L1 is the threshold value or more and the tractor <NUM> is positioned rightward from the target traveling route L1 (in a case where ΔL < <NUM>), the autonomous traveling controller <NUM> rotates the rotation shaft of the steering motor <NUM> so that the steering direction of the tractor <NUM> is orientated to the left. In this case, the expression, (ΔW - ΔL) > <NUM>, is satisfied because ΔW is equal to zero and ΔL is smaller than zero. The autonomous traveling controller <NUM> controls autonomous traveling of the tractor <NUM> so that the expression, (ΔW - ΔL), provides zero through leftward steering the tractor <NUM>.

The tractor <NUM> is capable of autonomously traveling on the target traveling route L1 through the above-mentioned control by the autonomous traveling controller <NUM>.

When an azimuth of the target traveling route L1 and an azimuth (that is, a vehicle azimuth) F1 of a traveling direction (that is, the traveling direction) of the tractor (that is, the traveling vehicle) <NUM> are different, that is, when an angle θg of the vehicle azimuth F1 relative to the target traveling route L1 is a threshold value or more (see <FIG>), the autonomous traveling controller <NUM> may perform a control to set a steering angle so that the angle θg becomes zero (that is, the vehicle azimuth F1 matches an azimuth of the target traveling route L1). The autonomous traveling controller <NUM> may set a final steering angle in autonomous steering based on a steering angle acquired based on the deviation (that is, a position deviation) and a steering angle acquired based on the azimuth (that is, an azimuth deviation). The setting of a steering angle in autonomous steering according to the above-mentioned embodiment is an example and is not limited thereto.

As shown in <FIG>, a lifting switch <NUM>, a steering angle detector <NUM>, and a changeover switch <NUM> are connected to the controller <NUM>. The controller <NUM> is capable of performing a manual lifting control, an autonomous lifting control, and the like based on operations of the lifting switch <NUM> and the changeover switch <NUM> and a steering angle detected by the steering angle detector <NUM>.

The manual lifting control is a control to lift and lower the working device <NUM> with the attaching unit (that is, the lifting device) <NUM> based on an operation of the lifting switch <NUM> operably connected to the controller <NUM>. Specifically, the lifting switch <NUM> is a three-position changeover switch located in a periphery of the driver seat <NUM>. When the lifting switch <NUM> is switched from a neutral position to one of the positions, a lifting signal to lift the lifting device <NUM> (that is, the lift arms 5a) is input to the controller <NUM>. When the lifting switch <NUM> is switched from the neutral position to the other, a lowering signal to lower the lifting device <NUM> (that is, the lift arms 5a) is input to the controller <NUM>. When the controller <NUM> acquires the lifting signal, the controller <NUM> outputs a control signal to a control valve (that is, a control valve for lift cylinder) to lift the attaching unit (that is, the lifting device) <NUM>, and when the controller <NUM> acquires the lowering signal, the controller <NUM> outputs a control signal to the control valve (that is, the control valve for lift cylinder) to lower the attaching unit <NUM>. That is, the controller <NUM> is capable of performing the manual lifting control for lifting and lowering the attaching unit <NUM> according to a manual operation of the lifting switch <NUM>.

The autonomous lifting control is a control to autonomously operate the attaching unit (that is, the lifting device) <NUM> when a steering angle of the steering device <NUM> is a predetermined angle or more, for example, the steering angle corresponds to a turn, thereby lifting the working device <NUM>. The steering angle detector <NUM> is a device configured to detect a steering angle of the steering device <NUM>. The changeover switch <NUM> is a switch configured to be switched between on and off to activate or inactivate the autonomous lifting control. When the changeover switch <NUM> is switched on, the autonomous lifting control is activated, and when the changeover switch <NUM> is switched off, the autonomous lifting control is inactivated.

When the autonomous lifting control is activated and a steering angle detected by the steering angle detector <NUM> is greater than or equal to a steering angle corresponding to a turn, the controller <NUM> performs the autonomous lifting control to autonomously lift the attaching unit <NUM> by outputting a control signal to a control valve (that is, a control valve for lift cylinder).

As described above, the controller <NUM> is capable of performing controls relating to the tractor <NUM>, for example, the manual lifting control and the autonomous lifting control.

As shown in <FIG>, the tractor <NUM> has an offset acquisition unit <NUM>.

The offset acquisition unit <NUM> is constituted of electrical and electronic circuits provided in the display device <NUM>, a computer program stored in an CPU, or the like. The offset acquisition unit <NUM> may be provided in the controller <NUM>.

The offset acquisition unit <NUM> acquires an offset amount ΔW (see <FIG> and <FIG>) and an offset direction in the vehicle width direction between the width directional center W1 of the tractor <NUM> and a predetermined point P1 in the working device <NUM>. The offset direction is a deviation direction (that is, a rightward or leftward direction) of the width directional center W1 of the tractor <NUM> in the vehicle width direction from the predetermined point P1 in the working device <NUM>. As described above, the width directional center W1 of the tractor <NUM> matches a position of the positioning device <NUM> in the vehicle width direction.

The predetermined point P1 in the working device <NUM> may be set at an appropriate position according to a type, shape, or the like of the working device <NUM>, and may be set so as to match the width directional center W2 of the working device <NUM> (see <FIG>) or may be set at a position that does not match the width directional center W2 of the working device <NUM> (a position deviating from the width directional center W2) (see <FIG>). The predetermined point P1 in the working device <NUM> matches the control target position PW1 described above.

<FIG> shows a case where the predetermined point P1 in the working device <NUM> matches the width directional center W2 of the working device <NUM> in the vehicle width direction. For example, as shown in <FIG>, when the width directional center W2 of the working device <NUM> matches a center W3 in a working width (for example, a cultivating width) WA of the working device <NUM>, the width directional center W2 of the working device <NUM> is set as the predetermined point P1. In this case, the offset acquisition unit <NUM> acquires the offset amount ΔW and the offset direction based on the width directional center W2 of the working device <NUM> serving as the predetermined point P1.

<FIG> shows a case where the predetermined point P1 in the working device <NUM> does not match the width directional center W2 of the working device <NUM> in the vehicle width direction. For example, as shown in <FIG>, when the width directional center W2 of the working device <NUM> does not match the center W3 in the work width WA, the center W3 in the work width WA is set as the predetermined point P1 in the working device <NUM> instead of the width directional center W2 of the working device <NUM>. In this case, the offset acquisition unit <NUM> acquires the offset amount ΔW and the offset direction by using a position (the center W3 in the work width WA) displaced from the width directional center W2 of the working device <NUM> as the predetermined point P1.

For example, when the working device <NUM> is a cultivator of center-drive type, the width directional center W2 of the working device <NUM> is used as the predetermined point P1 because the width directional center W2 of the working device <NUM> matches the center W3 of the working width (that is, a cultivating width) WA of the working device <NUM>. On the other hand, when the working device <NUM> is a side-drive cultivator, the center W3 of the working width WA is used as the predetermined point P1 in the working device <NUM> because the width directional center W2 of the working device <NUM> does not match the center W3 of the working width (that is, a cultivating width) WA of the working device <NUM>.

A specific configuration of the offset acquisition unit <NUM> will be described below, taking a case where the width directional center W2 of the working device <NUM> matches the center W3 of the working width (see <FIG>) as an example.

The offset acquisition unit <NUM> has a configuration (a first configuration) to acquire an offset amount and an offset direction input by an operator or a configuration (a second configuration) to acquire the offset amount and the offset direction based on a detection result detected by the detector <NUM> to be described below.

First, the first configuration of the offset acquisition unit <NUM> will be described.

The first configuration of the offset acquisition unit <NUM> is used when an offset direction and an offset amount of the width directional center W2 of the working device <NUM> from the width directional center W1 of the tractor <NUM> are known before starting of autonomous traveling of the tractor <NUM>. For example, it is used when an operator is aware that the attachment position of the working device <NUM> is deviated in the vehicle width direction at the time when the operator attaches the working device <NUM> to the attaching unit (that is, the lifting device) <NUM>.

As shown in <FIG>, the offset acquisition unit <NUM> displays, in a setting screen M1 of a display part <NUM> of the display device <NUM>, a figure D1 representing the tractor <NUM> and a figure D2 representing the working device <NUM>. In addition, the offset acquisition unit <NUM> displays, in the setting screen M1 displayed on the display part <NUM> of the display device <NUM>, an offset amount input portion <NUM> to which the offset amount ΔW is input and an offset direction input portion <NUM> to which a direction of offset (that is, deviation) is input.

The offset amount input portion <NUM> is a portion to which a deviation amount (that is, a distance) of the predetermined point in the working device <NUM> (the width directional center W2 of the working device <NUM>) from the width directional center W1 of the tractor <NUM> is input as the offset amount ΔW. The offset direction input portion <NUM> is a portion to which a deviation direction (that is, a rightward or leftward direction) of the width directional center W1 of the tractor <NUM> from the predetermined point P1 in the working device <NUM> (that is, the width directional center W2 of the working device <NUM>) is input. In <FIG>, the offset direction is the "left". It may be configured so that the deviation direction (that is, the right in <FIG>) of the predetermined point in the working device <NUM> (that is, the width directional center W2 of the working device <NUM>) from the width directional center W1 of the tractor <NUM> is input to the offset direction input portion <NUM>, and the offset acquisition unit <NUM> acquires the offset direction that is a direction (that is, the left in the same illustration) opposite to the inputted deviation direction.

An operator (that is, a driver) inputs the offset amount ΔW to the offset amount input portion <NUM> displayed on the display device <NUM>, and inputs an offset direction to the offset direction input portion <NUM>. The offset acquisition unit <NUM> acquires the offset amount ΔW inputted to the offset amount input portion <NUM> and the offset direction inputted to the offset direction input portion <NUM>.

Next, the second configuration of the offset acquisition unit <NUM> will be described.

The second configuration of the offset acquisition unit <NUM> is used, for example, when an offset direction and an offset amount of the width directional center W2 of the working device <NUM> from the width directional center W1 of the tractor <NUM> are not known before the starting of autonomous traveling of the tractor <NUM>. For example, it is used when an attachment position of the working device <NUM> is not deviated in the vehicle width direction at the time when an operator attaches the working device <NUM> to the attaching unit (that is, the lifting device) <NUM>, but there is a possibility that the deviation may occur during traveling.

The offset acquisition unit <NUM> in the second configuration acquires an offset amount and an offset direction based on a detection result detected by the detector <NUM>. The detector <NUM> detects a change in a position of the attaching unit (that is, the lifting device) <NUM> relative to a reference position. The reference position of the attaching unit <NUM> is a position of the attaching unit <NUM> where the width directional center W1 of the tractor <NUM> matches the predetermined point P1 in the working device <NUM> (the width directional center W2 of the working device <NUM>) in the vehicle width direction. <FIG> and <FIG> show a state of the attaching unit <NUM> positioning at the reference position. <FIG> is an overall view of the working vehicle <NUM>, and <FIG> is a main enlarged view of the working vehicle <NUM>.

The detector <NUM> is a sensor configured to detect a change when a position of the attaching unit <NUM> (that is, a position of the lower linkages 5b in the embodiment) moves from the reference position. For example, an angle sensor or a stroke sensor is used as the above-mentioned sensor.

<FIG> shows an example of a first detection mechanism <NUM> using an angle sensor <NUM> as the detector <NUM>.

The first detection mechanism <NUM> has a connecting rod <NUM>, an arm <NUM>, and an angle sensor <NUM>. The connecting rod <NUM> is connected (pivotally supported) at one end thereof to the middle portion of one of the lower linkages 5b and extends forward therefrom. The other end of the connecting rod <NUM> is connected (pivotally supported) to the arm <NUM>. One end of the arm <NUM> is connected (pivotally supported) to the other end of the connecting rod <NUM>. The other end of the arm <NUM> is connected (pivotally supported) to a side surface of the vehicle body <NUM> (that is, the transmission case <NUM>) of the tractor <NUM>.

When the lower linkages 5b are swung in the vehicle width direction (leftward or rightward) with the front end portions 5f as a fulcrum relative to the tractor <NUM>, the connecting rod <NUM> moves in the fore-and-aft direction according to the swinging. When the connecting rod <NUM> moves in the fore-and-aft direction, the arm <NUM> rotates centered on the second end thereof connected to the tractor <NUM>, and an angle α of the arm <NUM> from the connecting rod <NUM> changes.

The angle sensor <NUM> is attached to a junction between the connecting rod <NUM> and the arm <NUM>, and detects a change in the angle α between the connecting rod <NUM> and the arm <NUM>, the change being caused by rotation of the arm <NUM>.

For example, as shown in <FIG>, consider a case where the working device <NUM> moves (swings) rightward in the vehicle width direction relative to the tractor <NUM> during autonomous traveling of the tractor <NUM>, and the predetermined point P1 (that is, the width directional center W2) in the working device <NUM> is offset rightward from the width directional center W1 of the tractor <NUM>. In this case, the lower linkages 5b to which the working device <NUM> are connected swing rightward from the tractor <NUM> using the front end portions 5f as fulcrums, thereby causing the connecting rod <NUM> to move forward. When the connecting rod <NUM> moves forward, the angle α changes (that is, decreases), and the angle sensor <NUM> detects this change in angle.

As described above, the angle sensor <NUM>, which is the detector <NUM> in the first detection mechanism <NUM>, detects a change in angle αrelative to the angle α formed when the attaching unit <NUM> is at the reference position (that is, a difference between the angle α in <FIG> and the angle α in <FIG>), and thus detects a change in position of the attaching unit <NUM> in the vehicle width direction relative to the reference position (that is, swinging in the vehicle width direction).

<FIG> shows an example of a second detection mechanism <NUM> using a stroke sensor <NUM> as the detector <NUM>.

The second detection mechanism <NUM> has a cylinder device <NUM>, an arm <NUM>, and a stroke sensor <NUM>. The cylinder device <NUM> has a tip end (that is, a tip end of a rod 67a) connected (pivotally supported) to the middle of one of the lower linkages 5b, and a base end (that is, a base end of a tube 67b) connected (pivotally supported) to one end of the arm <NUM>.

The cylinder device <NUM> extends in the fore-and-aft direction, and the rod 67a can be extended and contracted in the fore-and-aft direction. The other end of the arm <NUM> is connected to the side surface of the vehicle body <NUM> (that is, the transmission case <NUM>) of the tractor <NUM>. An angle of the arm <NUM> relative to the vehicle body <NUM> is fixed. The stroke sensor <NUM> is attached to the cylinder device <NUM> and detects an extending or contracting extent of the rod 67a of the cylinder device <NUM>.

When the lower linkages 5b are swung in the vehicle width direction (leftward or rightward) with the front end portions 5f as the fulcrum relative to the tractor <NUM>, the rod 67a of the cylinder device <NUM> extends or contracts according to the swinging, and the stroke sensor <NUM> detects the extending or contracting extent of the rod 67a.

For example, as shown in <FIG>, consider a case where the working device <NUM> moves (swings) rightward in the vehicle width direction relative to the tractor <NUM> during autonomous traveling of the tractor <NUM>, and the predetermined point P1 (that is, the center W2 in width direction) in the working device <NUM> is offset rightward relative to the width directional center W1 of the tractor <NUM>. In this case, the lower linkages 5b to which the working device <NUM> is connected swing rightward relative to the tractor <NUM> with the front end portions 5f as the fulcrums, and a length of the rod 67a of the cylinder device <NUM> changes (shortens).

The stroke sensor <NUM> detects this change in length of the rod 67a of the cylinder device <NUM>.

As described above, the stroke sensor <NUM>, which is the detector <NUM> in the second detection mechanism <NUM>, detects a change in length (that is, a change in stroke) relative to a length of the rod 67a of the cylinder device <NUM> when the attaching unit <NUM> is at the reference position, and thereby detecting a change in position of the attaching unit <NUM> in the vehicle width direction relative to the reference position (that is, detecting swinging in the vehicle width direction).

The above description explains the case where the angle sensor <NUM> or the stroke sensor <NUM> is used as the detector <NUM>, however the detector <NUM> is not limited to the angle sensor <NUM> and the stroke sensor <NUM>. For example, the detector <NUM> may be constituted of a camera attached to the tractor <NUM> and an image analyzer configured to analyze images captured by the camera. This case can have a configuration where a camera captures the attaching unit <NUM> or the working device <NUM>, and the image analyzer detects, based on the captured image, a change in position of the attaching unit <NUM> or the working device <NUM> in the vehicle width direction.

The offset acquisition unit <NUM> calculates and acquires the offset amount ΔW and an offset direction based on a changing extent detected by the detector <NUM>. For example, when the detector <NUM> is an angle sensor <NUM>, the offset acquisition unit <NUM> calculates and acquires the offset amount ΔW and an offset direction based on a changing extent of the angle α detected by the detector <NUM> and known information previously input to and stored in the offset acquisition unit <NUM> (e.g., lengths and attachment angles of the lower linkages 5b, a length of the working device <NUM> in the vehicle width direction, a length of the arm <NUM>, a length of the connecting rod <NUM>, positions of the front end portions 5f of the lower linkages 5b, a connecting position of the arm <NUM> relative to the tractor <NUM>, a connecting position of the connecting rod <NUM> relative to the lower linkages 5b, the angle α formed when the working device <NUM> is at the reference position).

For example, when the detector <NUM> is the stroke sensor <NUM>, the offset acquisition unit <NUM> calculates and acquires the offset amount ΔW and an offset direction based on a changing extent of the rod 67a detected by the detector <NUM> and known information previously input to and stored in the offset acquisition unit <NUM> (e.g., lengths and attachment angles of the lower linkages 5b, a length of the working device <NUM> in the vehicle width direction, a length of the arm <NUM>, a length of the cylinder device <NUM>, positions of the front end portions 5f of the lower linkages 5b, a connecting position of the arm <NUM> relative to the tractor <NUM>, a connecting position of the rod 67a relative to the lower linkages 5b, a length of the rod 67a at the time when the working device <NUM> is at the reference position).

As shown in <FIG>, the autonomous traveling controller <NUM> of the tractor <NUM> has a traveling position corrector <NUM> configured to correct a traveling position of the tractor <NUM>. The traveling position corrector <NUM> is constituted of electrical and electronic circuits provided in the controller <NUM>, a computer program stored in a CPU, or the like. The traveling position corrector <NUM> may be configured as a part of the autonomous traveling controller 44b, or may be configured separately from the autonomous traveling controller <NUM> but may be operable in synchronization with the autonomous traveling controller <NUM>. The traveling position corrector <NUM> may be provided in the display device <NUM>.

The traveling position corrector <NUM> corrects a traveling position of the tractor <NUM> so that the predetermined point P1 (that is, the control target position PW1) in the working device <NUM> is located on the target traveling route L1 based on an offset amount and an offset direction acquired by the offset acquisition unit <NUM>. In detail, the traveling position corrector <NUM> corrects a traveling position of the tractor <NUM> based on an offset amount and an offset direction when the predetermined point P1 in the working device <NUM> is not located on the target traveling route L1 and the offset amount ΔW is not equal to zero (for example, in a case shown in <FIG>). The correction of the traveling position of the tractor <NUM> by the traveling position corrector <NUM> is executed in a manner in which the autonomous traveling controller <NUM> changes steering directions of the front wheels 4F based on a command (that is, a control signal) from the traveling position corrector <NUM>.

The "control based on an offset direction" executed by the traveling position corrector <NUM> includes two types of control.

A first control is executed when an offset direction of the width directional center W1 of the tractor <NUM> from the predetermined point P1 in the working device <NUM> matches a displacement direction of the target traveling route L1 from the predetermined point P1 in the working device <NUM>.

A second control is executed when an offset direction of the width directional center W1 of the tractor <NUM> from the predetermined point P1 in the working device <NUM> does not match (that is, in opposite direction to) a displacement direction of the target traveling route L1 from the predetermined point P1 in the working device <NUM>.

Referring to <FIG> and <FIG>, the two types of control executed by the traveling position corrector <NUM> will be described below. Here, a case where the predetermined point P1 (that is, the control target position PW1) in the working device <NUM> is at the width directional center W2 of the working device <NUM> will be described.

<FIG> shows a case where the traveling position corrector <NUM> executes the first control.

A lower drawing in <FIG> shows a vehicle state before the first control is executed. At this time, the width directional center W1 of the tractor <NUM> (that is, the detected vehicle position PW2) is located on the target traveling route L1, however the predetermined point P1 in the working device <NUM> (that is, the control target position PW1) is offset by ΔW4 from the detected vehicle position PW2 and is not located on the target traveling route L1. An offset direction (right) C1 of the width directional center W1 of the tractor <NUM> from the predetermined point P1 in the working device <NUM> matches a displacement direction (right) C2 of the target traveling route L1from the predetermined point P1 in the working device <NUM>. In this case, ΔL is equal to <NUM>, ΔW and ΔW4 are equal but not zero, and (ΔW - ΔL) and ΔW4 are equal but not zero in the above-mentioned expression; the control target position PW1 = the detected vehicle position PW2 + (ΔW - ΔL).

In this case, the offset acquisition unit <NUM> acquires "ΔW4" as the offset amount and "right" as the offset direction in the first or second configurations described above. The traveling position corrector <NUM> outputs, to the autonomous traveling controller <NUM>, a control signal based on the offset amount and offset direction acquired by the offset acquisition unit <NUM>, specifically, a control signal to move the tractor <NUM> by the offset amount ΔW4 in the same direction (rightward) as the offset direction C1. The autonomous traveling controller <NUM> shifts a traveling position of the tractor <NUM> to the right by the offset amount ΔW4 by steering the front wheels 4F to the same side (rightward) as the offset direction based on the control signal. In this manner, as shown in an upper portion of <FIG>, a traveling position of the tractor <NUM> is corrected so that the predetermined point P1 in the working device <NUM> (that is, the control target position PW1) is located on the target traveling route L1. That is, the autonomous traveling controller <NUM> controls the autonomous traveling of the tractor <NUM> so that an expression, (ΔW - ΔL) = <NUM>, is satisfied by steering the tractor <NUM> rightward.

<FIG> shows a case where the traveling position corrector <NUM> executes the second control.

A lower drawing in <FIG> shows a vehicle state before the second control is executed. At this time, the width directional center W1 of the tractor <NUM> (that is, the detected vehicle position PW2) is displaced by ΔL from the target traveling route L1. The predetermined point P1 in the working device <NUM> (that is, the control target position PW1) is offset by ΔW5 from the detected vehicle position PW2 and is not located on the target traveling route L1. An offset direction (right) C3 of the width directional center W1 of the tractor <NUM> from the predetermined point P1 in the working device <NUM> does not match (that is, in opposite direction to) a displacement di-rection (left) C4 of the target traveling route L1 from the predetermined point P1 in the working device <NUM>. In this case, ΔL is not equal to <NUM>, ΔW and ΔW5 are equal but not zero, and (ΔW - ΔL) is not zero in the above-mentioned expression; the control target position PW1 = the detected vehicle position PW2 + (ΔW - ΔL).

In this case, the offset acquisition unit <NUM> acquires "ΔW5" as the offset amount and "right" as the offset direction. The traveling position corrector <NUM> outputs, to the autonomous traveling controller <NUM>, a control signal based on an offset amount and offset direction acquired by the offset acquisition unit <NUM>, specifically, a control signal to move the tractor <NUM> in a direction opposite to the offset direction C3 (left) by the offset amount ΔW5. The autonomous traveling controller <NUM> shifts a traveling position of the tractor <NUM> to the left by the offset amount ΔW5 by steering the front wheels 4F in a direction opposite to the offset direction (left) based on the control signal. In this manner, as illustrated by an upper drawing in <FIG>, a traveling position of the tractor <NUM> is corrected so that the predetermined point P1 in the working device <NUM> (that is, the control target position PW1) is located on the target traveling route L1. That is, the autonomous traveling controller <NUM> controls the autonomous traveling of the tractor <NUM> so that an expression, (ΔW - ΔL) = <NUM>, is satisfied by steering the tractor <NUM> leftward.

As described above, the traveling position corrector <NUM> steers the front wheels 4F in the same direction as the offset direction in the first control, and steers the front wheels 4F in the direction opposite to the offset direction in the second control as the "control based on an offset direction. In this manner, even when the working device <NUM> is offset in the vehicle width direction from the tractor <NUM>, a work trace of the working device <NUM> can be prevented from deviating in the vehicle width direction from the target traveling route L1.

As shown in <FIG>, the traveling position corrector <NUM> does not correct a traveling position in the vehicle width direction when the predetermined point P1 in the working device <NUM> (that is, the control target position PW1) is located on the target traveling route L1. When ΔL is equal to ΔW and a displacement direction C5 of the detected vehicle position PW2 from the target traveling route L1 is the same as an offset direction C6 acquired by the offset acquisition unit <NUM> (in a case of <FIG>), the traveling position corrector <NUM> determines that the predetermined point P1 in the working device <NUM> (that is, the control target position PW1) is located on the target traveling route L1, and accordingly the traveling position is not corrected. In this case, since the predetermined point P1 in the working device <NUM> is located on the target traveling route L1, no correction to the travel position is required.

In correcting a traveling position of the tractor <NUM> based on an offset amount and an offset di-rection acquired by the offset acquisition unit <NUM>, the traveling position corrector <NUM> may determine that the predetermined point P1 in the working device <NUM> is located on the target traveling route L1 when an expression, (ΔW - ΔL), is not zero but is less than a predetermined threshold. In this case, the traveling position corrector <NUM> controls autonomous traveling of the tractor <NUM> so that an expression, (ΔW - ΔL), is less than a threshold.

The tractor <NUM> may have a switching device that switches the traveling position corrector <NUM> between to be in use and to be not in use. For example, the traveling position corrector <NUM> can be not in use when the tractor <NUM> travels without the working device <NUM> or when an offset in the vehicle width direction between the width directional center of the tractor <NUM> and the predetermined point in the working device <NUM> is allowed depending on work contents or the like. When the traveling position corrector <NUM> is not in use, the tractor <NUM> autonomously travels so that the width directional center W1 follows the target traveling route L1 because no correction is made by the traveling position corrector <NUM>.

According to the above-mentioned working vehicle <NUM>, the following effects are provided.

The working vehicle <NUM> includes the traveling vehicle <NUM> configured to autonomously travel on the target traveling route L1, the working device <NUM> attached to the traveling vehicle <NUM>, the offset acquisition unit <NUM> to acquire an offset amount and an offset direction in the vehicle width direction between the width directional center W1 of the traveling vehicle <NUM> and the predetermined point P1 in the working device <NUM>, and the traveling position corrector <NUM> to correct, based on the offset amount and the offset direction acquired by the offset acquiring unit <NUM>, a traveling position of the traveling vehicle <NUM> so that the predetermined point P1 is located on the target traveling route L1.

According to this configuration, the traveling position corrector <NUM> is capable of correcting, based on the offset amount and the offset direction of the predetermined point P1 in the working device <NUM> acquired by the offset acquisition unit <NUM>, the traveling position of the traveling vehicle <NUM> so that the predetermined point P1 is located on the target traveling route L1. Thus, even in a case where the working device <NUM> is offset in the vehicle width direction from the traveling vehicle <NUM>, a work trace of the working device <NUM> can be prevented from deviating in the vehicle width direction from the target traveling route L1.

In addition, the working device <NUM> is attached to the rear portion of the traveling vehicle <NUM>. The offset acquisition unit <NUM> acquires the offset amount and the offset direction based on the width directional center W2 of the working device <NUM> serving as the predetermined point P1.

According to this configuration, since the width directional center W2 of the working device <NUM> is defined as the predetermined point P1, the predetermined point P1 can be easily set based on a width (that is, a length in the vehicle width direction) of the working device <NUM>.

In addition, the working vehicle <NUM> includes the display device <NUM> configured to display the offset amount input portion <NUM> to which the offset amount is input and the offset direction input portion <NUM> to which the offset direction is input. The offset acquisition unit <NUM> acquires the offset amount input to the offset amount input portion <NUM> and the offset direction input to the offset direction input portion <NUM>.

According to this configuration, the offset amount and the offset direction can be acquired reliably without need for an additional configuration (that is, a sensor or the like) to acquire the offset amount and the offset direction.

In addition, the working vehicle <NUM> includes the attaching unit <NUM> provided on the rear portion of the traveling vehicle <NUM> and configured to have the working device <NUM> attached thereto, and the detector <NUM> to detect a change in position of the attaching unit <NUM> in the vehicle width direction relative to the reference position that is the position of the attaching unit <NUM> at which the width directional center W1 of the traveling vehicle <NUM> matches the predetermined point P1 in the vehicle width direction. The offset acquisition unit <NUM> acquires the offset amount and the offset direction based on the change detected by the detector <NUM>.

According to this configuration, even when the predetermined point P1 in the working device <NUM> is offset in the vehicle width direction from the width directional center W1 of the traveling vehicle <NUM> during autonomous traveling of the traveling vehicle <NUM>, the offset amount and the offset direction can be acquired reliably.

In addition, the attaching unit <NUM> is constituted of the three-point linkage mechanism having the lower linkages 5b, the top linkage 5c, and the lift rod 5d. The working device <NUM> is connected to at least the lower linkages 5b, and the detector <NUM> includes the sensors <NUM> and <NUM> to detect the change when the positions of the lower linkages 5b change from the reference position.

According to this configuration, by detecting a change in positions of the lower linkages 5b with the sensors <NUM> and <NUM>, the offset acquisition unit <NUM> can acquire the offset amount and the offset direction, so that the offset amount and the offset direction can be easily acquired with such a simple configuration.

In addition, the sensor is the angle sensor <NUM> or the stroke sensor <NUM>.

Claim 1:
A working vehicle (<NUM>) comprising:
- a traveling vehicle (<NUM>) configured to perform an autonomous travel along a target traveling route (L1);
- a working device (<NUM>) attached to the traveling vehicle (<NUM>);
- an offset acquisition unit (<NUM>) to acquire an offset amount (ΔW) and an offset di-rection (C1, C3) in a vehicle width direction between a width directional center (W1) of the traveling vehicle and a predetermined point (P1) in the working device (<NUM>); and
- a traveling position corrector (<NUM>) to correct, based on the offset amount (ΔW) and the offset direction (C1, C3) acquired by the offset acquisition unit (<NUM>), a traveling position of the traveling vehicle (<NUM>) so that the predetermined point (P1) is located on the target traveling route,
wherein the working vehicle is configured such that:
when, in the vehicle width direction, a width directional center (W2) of the working device (<NUM>) matches a center (W3) in a working width (WA) of the working device (<NUM>), the offset acquisition unit (<NUM>) acquires the offset amount (ΔW) and the offset direction (C1, C3) based on the width directional center (W2) of the working device (<NUM>) serving as the predetermined point (P1); and
characterized in that the working vehicle is configured such that
when, in the vehicle width direction, the width directional center (W2) of the working device (<NUM>) does not match the center (W3) in the working width (WA) of the working device (<NUM>), the offset acquisition unit (<NUM>) acquires the offset amount (ΔW) and the offset direction (C1, C3) based on the center (W3) in the working width (WA) of the working device (<NUM>) serving as the predetermined point (P1).