Patent Description:
Patent document <NUM>: <CIT> is known as an automatic traveling working vehicle which travels while doing work along a travel route. The working vehicle (tractor) disclosed in Patent document <NUM> includes a vehicle body equipped with a working device, a work/travel control unit to control work/travel, a set of work/travel state detecting sensors to detect work/travel states thereof, at least one obstacle sensor to detect obstacles which hinder travel, an obstacle detecting unit to detect obstacles present within an obstacle monitoring area according to a sensor signal from the at least one obstacle sensor, and an obstacle monitoring area deciding unit to decide an obstacle monitoring area according to the work/travel states detected by the set of work/travel state detecting sensors.

<CIT> describes an automatic travel device of a work vehicle capable of efficiently monitoring an obstacle while reducing an electric power consumption measured by an obstacle sensor, in accordance with a travel state of the work vehicle on a target travel route, when the work vehicle is made to automatically travel along the target travel route. <CIT> describes obstacle detection devices capable of reducing or preventing erroneous detection of an obstacle in an obstacle detection target area including both a short-distance area that exhibits an irregular disturbance in the sound pressure distribution and a long-distance area that exhibits a uniform sound pressure distribution.

<CIT> describes a work vehicle capable of avoiding contact of an obstacle with a rear part of a vehicle body.

With the working vehicle of Patent document <NUM>, the obstacle monitoring area is decided according to the work/travel states. However, the obstacle monitoring area is decided only according to the working state during forward travel, and a rear area in which the working device is attached is not taken into consideration. That is, in reality, the obstacle monitoring area is not changed according to the working device of Patent document <NUM> or not changed according to work.

In view of such circumstances, an object of the present invention is to provide a working vehicle which makes it possible to improve workability while efficiently performing automatic travel by changing information regarding detection of obstacles behind the vehicle body. The present invention is defined by the independent claim. Preferred examples are defined in the dependent claims.

The present invention makes it possible to improve workability while achieving efficient automatic travel by changing information regarding detection of obstacles behind the vehicle body.

The following description discusses preferred embodiments of the present invention with reference to drawings.

<FIG> and <FIG> illustrate an embodiment of a working vehicle <NUM> according to the present invention. The present embodiment is discussed based on the assumption that the working vehicle <NUM> is a tractor <NUM>. Note, however, that the working vehicle <NUM> is not limited to a tractor, and may be some other working vehicle (agricultural vehicle) such as a combine or a rice transplanter.

In the following description, the front of the tractor <NUM> as seen from an operator seated on the operator's seat <NUM> is referred to as "front", the rear of the tractor <NUM> as seen from the operator is referred to as "rear", the left side of the tractor <NUM> as seen from the operator is referred to as "left", and the right side of the tractor <NUM> as seen from the operator is referred to as "right". Furthermore, a direction indicated by arrow D is referred to as a vehicle width direction. Furthermore, a vehicle width direction going away from the widthwise center of the vehicle is referred to as a "vehicle width outward direction", and a vehicle width direction approaching the widthwise center of the vehicle is referred to as a "vehicle width inward direction".

As illustrated in <FIG> and <FIG>, the tractor <NUM> includes a vehicle body <NUM>, a traveling device <NUM>, a prime mover <NUM>, and a transmission <NUM>. The traveling device <NUM> supports the vehicle body <NUM> such that the vehicle body <NUM> can travel, and includes front wheel(s) 3F and rear wheel(s) 3R. The front wheel(s) 3F and the rear wheel(s) 3R in the present embodiment are in the form of tires, but may be in the form of crawlers.

The prime mover <NUM> is an engine (diesel engine, gasoline engine), an electric motor, and/or the like. The transmission <NUM> is capable of changing driving forces for the traveling device <NUM> by changing speed stages and switching the traveling state of the traveling device <NUM> between forward and rearward traveling states.

The vehicle body <NUM> is equipped with the operator's seat <NUM>. An operator's seat protector <NUM> is provided around the operator's seat <NUM>. In the present embodiment, the operator's seat protector <NUM> is a cabin which surrounds the front, rear, upper, and lateral sides of the operator's seat <NUM> to protect the operator's seat <NUM>, but may be a ROPS or the like. A linkage <NUM> is provided at the rear of the vehicle body <NUM>. The linkage <NUM> is a swinging drawbar which connects a working device <NUM> and the vehicle body <NUM> but does not raise or lower the working device <NUM>, a raising/lowering device which is composed of a three-point linkage or the like and which raises and lowers the working device <NUM>, or the like. The linkage is configured to have the working device (implement or the like) <NUM> detachably attached thereto.

By linking the working device <NUM> to the linkage <NUM>, it is possible to allow the vehicle body <NUM> to tow the working device <NUM>. The working device <NUM> is, for example, a cultivator for cultivation, a fertilizer spreader for spreading fertilizer, an agricultural chemical spreader for spreading agricultural chemicals, a harvester for harvesting, a mower for mowing grass or the like, a tedder for tedding grass or the like, a rake for raking grass or the like, a baler for baling grass or the like, or the like.

The vehicle body <NUM> includes a vehicle body frame <NUM>. The vehicle body frame <NUM> extends in a direction from the transmission <NUM> to the front, and supports a lower portion of the prime mover <NUM>. As illustrated in <FIG>, a hood <NUM> is provided above the vehicle body frame <NUM>. The hood <NUM> extends in a front-rear direction along the vehicle body frame <NUM>. The hood <NUM> is disposed forward of a central portion of the operator's seat protector <NUM> in the vehicle width direction. The hood <NUM> includes a left side wall <NUM> provided on the left side, a right side wall 13R provided on the right side, and a top wall portion 13U which connects upper portions of the left side wall <NUM> and the right side wall 13R. The left side wall <NUM>, the right side wall 13R, and the top wall portion 13U define an engine room, and the engine room houses therein the prime mover <NUM>, a cooling fan, a radiator, a battery, and/or the like. The front wheels 3F are disposed leftward of the left side wall <NUM> and rightward of the right side wall 13R, respectively.

A weight <NUM> is provided forward of the hood <NUM>, i.e., forward of the vehicle body frame <NUM>. The weight <NUM> is attached to a weight bracket <NUM> provided at the front of the vehicle body <NUM>. The weight bracket <NUM> is attached to a front portion of the vehicle body frame <NUM> with fastener(s) such as bolt(s). The weight <NUM> is surrounded and covered by a weight cover <NUM>.

As illustrated in <FIG>, the tractor <NUM> includes a steering unit <NUM>. The steering unit <NUM> includes a steering wheel 11a, a rotation shaft (steering shaft) 11b which rotates as the steering wheel 11a rotates, and an assist mechanism (power steering mechanism) 11c to assist steering performed using the steering wheel 11a. The assist mechanism 11c includes a hydraulic pump <NUM>, a control valve <NUM> supplied with hydraulic fluid discharged from the hydraulic pump <NUM>, and a steering cylinder <NUM> which is caused to function by the control valve <NUM>. The control valve <NUM> is a solenoid valve which functions based on a control signal. The control valve <NUM> is, for example, a three-way switching valve which achieves multi-position switching by movement of a spool or the like. The positions of the control valve <NUM> can also be switched by steering by the steering shaft 11b. The steering cylinder <NUM> is connected to arms (knuckle arms) <NUM> which change the orientation of the front wheels 3F.

Therefore, upon operation of the steering wheel 11a, the position and the degree of opening of the control valve <NUM> change according to the steering wheel 11a, and the steering cylinder <NUM> extends or retracts leftward or rightward according to the position and the degree of opening of the control valve <NUM>, making it possible to change the steering direction of the front wheels 3F. Note that the foregoing steering unit <NUM> is an example, and a configuration of the steering unit <NUM> is not limited to that described above.

As illustrated in <FIG> and <FIG>, the tractor <NUM> includes a position detecting device <NUM>. The position detecting device <NUM> is attached to a front portion of a top plate of the cabin <NUM> via a mount <NUM>. Note, however, that the location at which the position detecting device <NUM> is attached is not limited to that illustrated in <FIG> and <FIG>, and the position detecting device <NUM> may be attached to the top plate of the cabin <NUM>, some other location on the vehicle body <NUM>, or the like location. The position detecting device <NUM> may be attached to the foregoing working device such as a cultivator.

The position detecting device <NUM> is a device to detect the position thereof (measured position information including latitude and longitude) using a satellite positioning system. Specifically, the position detecting device <NUM> receives signals (positions of positioning satellites, time of transmission, correction information, and/or the like) from positioning satellites, and detects the position (latitude and longitude) on the basis of the received signals. The position detecting device <NUM> may detect, as the position thereof (latitude and longitude), a position corrected with a signal such as a correction signal from a base station (reference station) which is capable of receiving signals from the GPS satellites. The position detecting device <NUM> may include an inertial measurement unit such as a gyroscope sensor and/or an acceleration sensor and detect, as the position thereof, a position corrected by the inertial measurement unit. With the position detecting device <NUM>, it is possible to detect the position of the vehicle body <NUM> of the tractor <NUM> (position of the vehicle body <NUM> that is traveling). The position of the tractor <NUM> itself detected by the position detecting device <NUM> may be the position of the center of the vehicle body <NUM> or may be, for example, the position of the front wheels 3F (e.g., the position of the front edge) or the position of the rear wheels 3R (e.g., the position of the rear edge).

As illustrated in <FIG> and <FIG>, the tractor <NUM> includes obstacle detecting devices <NUM> to detect obstacles which would hinder travel. The obstacle detecting devices <NUM> include front obstacle detecting devices 31A and a rear obstacle detecting device 31B. The front obstacle detecting devices 31A are each a device configured to detect obstacles in front of the vehicle body <NUM>. The rear obstacle detecting device 31B is a device configured to detect obstacles behind the vehicle body <NUM>. The front obstacle detecting devices 31A and the rear obstacle detecting device 31B are laser scanners to detect obstacles by emitting light waves as detection waves. Note, however, that each obstacle detecting device may be a sensor (range sensor) other than laser scanners, such as a sonar which detects obstacles by emitting sound waves (ultrasonic waves) as detection waves.

The front obstacle detecting devices 31A are provided at different positions from the rear obstacle detecting device 31B in the front-rear direction. In the present embodiment, the front obstacle detecting devices 31A are provided forward of the rear obstacle detecting device 31B. The front obstacle detecting devices 31A are disposed forward of the front wheels 3F. The front obstacle detecting devices 31A are disposed outward of the front wheels 3F in the vehicle width outward directions (disposed on the vehicle width outward sides of the front wheels 3F). The front obstacle detecting devices 31A are disposed outward of the rear wheels 3R in the vehicle width outward directions (disposed on the vehicle width outward sides of the rear wheels 3R).

The front obstacle detecting devices 31A are disposed at a position diagonally leftward and forward of the left front wheel 3F and a position diagonally rightward and forward of the right front wheel 3F, respectively. The front obstacle detecting device 31A disposed diagonally leftward and forward of the left front wheel 3F and the front obstacle detecting device 31A disposed diagonally rightward and forward of the right front wheel 3F are located symmetrically with respect to a center line bisecting the width of the tractor <NUM>.

Each front obstacle detecting device 31A is attached to the vehicle body frame <NUM> via a mounting structure <NUM>. As illustrated in <FIG> and <FIG>, the mounting structure <NUM> includes a first structure <NUM>, a second structure <NUM>, a third structure <NUM>, and a fourth structure <NUM>. The first structure <NUM> is attached to the vehicle body frame <NUM>, and extends from the vehicle body frame <NUM> diagonally forward and in a vehicle width outward direction (extends diagonally forward and leftward or extends diagonally forward and rightward). The second structure <NUM> is attached to a front end (distal end) of the first structure <NUM>. The second structure <NUM> extends outward along the width direction of the machine body and supports the front obstacle detecting device 31A. A sonar <NUM> other than a sonar of the rear obstacle detecting device 31B is attached to the second structure <NUM>. The direction of laser emitted from the front obstacle detecting device 31A is a horizontal direction.

The front obstacle detecting device 31A and a part of the second structure <NUM> are covered by a cover <NUM>. The cover <NUM> is attached to the second structure <NUM> with mounting member(s) such as bolt(s). The cover <NUM> is composed of an upper cover disposed above the front obstacle detecting device 31A and a lower cover disposed below the front obstacle detecting device 31A. Around the front obstacle detecting device 31A, a gap G is formed between the upper cover 56A and the lower cover 56B (see <FIG>), and the front obstacle detecting device 31A can emit and receive detection waves (laser) through the gap G. The sonar <NUM> can emit and receive detection waves (sound waves) through an opening in the upper cover 56A.

The rear obstacle detecting device 31B is attached to an upper rear portion of the cabin <NUM> via a bracket (not illustrated). The detecting direction of the rear obstacle detecting device 31B is inclined slightly downward with respect to a horizontal direction, i.e., oriented toward the working device <NUM>. Note that the detecting direction means the direction of the optical axis along which laser is emitted in the case where the rear obstacle detecting device 31B is a laser scanner, the direction in which sound waves are emitted in the case where the rear obstacle detecting device 31B is a sonar, and the direction of the optical axis of an image sensor (central axis of a lens) in the case where the rear obstacle detecting device 31B is a camera.

Each front obstacle detecting device 31A stores front setting information regarding obstacle detection, and the rear obstacle detecting device 31B stores rear setting information regarding obstacle detection. The front setting information and the rear setting information include various types of information for the obstacle detecting devices <NUM> (front obstacle detecting devices 31A and the rear obstacle detecting device 31B) to detect obstacles, such as monitored areas, criteria for determination of whether an object detected in a monitored area is an obstacle or not, and/or the like.

First, the monitored areas are discussed.

<FIG> illustrates examples of monitored areas Q1 and Q2 of the front obstacle detecting devices 31A and the rear obstacle detecting device 31B.

The monitored area Q1 of each front obstacle detecting device 31A includes a side area Qa1 extending from the front obstacle detecting device 31A to the rear of the vehicle body <NUM> and an area lateral to the vehicle body <NUM> (an area outward of the vehicle body <NUM> in the width direction) and a front area Qa2 extending from the front obstacle detecting device 31A in a vehicle width inward direction in front of the vehicle body <NUM>. Each side area Qa1 is defined by monitor dimensions L1 and L2 each extending outward along the width direction and a dimension L3 along the front-rear direction. The front areas Qa2 are defined by a monitor dimension L6 extending forward and a monitor dimension L5 along the width direction. As shown in <FIG>, default values (reference monitored area, reference monitor dimensions) of the size (monitor dimensions L1, L2, L3, L5, and L6) of the monitored area Q1 are stored as front setting information for the front obstacle detecting devices 31A.

The monitored area Q2 of the rear obstacle detecting device 31B extends from the rear obstacle detecting device 31B to an area rearward of the vehicle body <NUM>, and is defined by a monitor dimension L10 extending rearward and a monitor dimension L11 extending along the width direction. As shown in <FIG>, default values (reference monitored area, reference monitor dimensions) of the size (monitor dimensions L10 and L11) of the monitored area Q2 are stored as rear setting information for the rear obstacle detecting device 31B. Note that the sizes of the monitored areas Q1 and Q2 of the front obstacle detecting devices 31A and the rear obstacle detecting device 31B can be freely set, and thus the width, length, angle, and/or the like thereof can be changed.

<FIG> illustrates examples of an object M1 detected by the front obstacle detecting device(s) 31A and an object M2 detected by the rear obstacle detecting device 31B.

In <FIG>, when an object M1 is located within a monitored area Q1, the front obstacle detecting device 31A detects the object (detected object) M1. If a height H1 of the detected object M1 is equal to or more than a height threshold H2 (H1 ≥ H2) and an object width W1 of the detected object M1 is equal to or more than a width threshold W2 (W1 ≥ W2), the front obstacle detecting device 31A determines the detected object M1 as an obstacle. If the height H1 of the detected object M1 is less than the height threshold H2 or the object width W1 of the detected object M1 is less than the width threshold W2, the front obstacle detecting device 31A determines the detected object M1 as not an obstacle. As shown in <FIG>, the front obstacle detecting device 31A stores the height threshold H2 and the width threshold W2 as criteria for determination of whether or not the detected object M1 is an obstacle. That is, the front obstacle detecting device 31A stores the height threshold H2 and the width threshold W2, which are criteria, as front setting information.

When an object M2 is located within the monitored area Q2, the rear obstacle detecting device 31B detects the object (detected object) M2. According to an example which is out of scope of the invention, if a height H3 of the detected object M2 is equal to or more than a height threshold H4 (H3 ≥ H4) and an object width W3 of the detected object M2 is equal to or more than a width threshold W4 (W3 ≥ W4), the rear obstacle detecting device 31B determines the detected object M2 as an obstacle. If the height H3 of the detected object M2 is less than the height threshold H4 or the object width W3 of the detected object M2 is less than the width threshold W4, the rear obstacle detecting device 31B determines the detected object M2 as not an obstacle. As shown in <FIG>, the rear obstacle detecting device 31B stores the height threshold H4 and the width threshold W4 as criteria for determination of whether or not the detected object M2 is an obstacle. That is, the rear obstacle detecting device 31B stores the height threshold H4 and the width threshold W4, which are criteria, as rear setting information.

In the foregoing embodiment, whether the detected object M1 is an obstacle or not is determined based on the size H1 and object width W1 of the detected object M1, but whether the detected object M1 is an obstacle or not may be determined based on a period of time for which the detected object M1 is located in the monitored area Q1 (a period of time for which the detected object M1 stays in the monitored area Q1.

The front obstacle detecting device 31A includes a second time calculation unit <NUM> and a second obstacle determination unit <NUM>. The second time calculation unit <NUM> and the second obstacle determination unit <NUM> are each composed of electric circuit(s), electronic circuit(s), and/or the like provided in the front obstacle detecting device 31A, program(s) stored in the front obstacle detecting device 31A, and/or the like.

The second time calculation unit <NUM> calculates a detection time (second detection time) T2 that is a period of time for which the detected object M1 is located in the monitored area Q1. The second obstacle determination unit <NUM> determines the detected object M1 as an obstacle if the second detection time T2 calculated by the second time calculation unit <NUM> is equal to or greater than a second threshold T11, and determines the detected object M1 as not an obstacle if the second detection time T2 is less than the second threshold T11. Note that the front obstacle detecting device 31A stores the second threshold T11 as a criterion. That is, the front obstacle detecting device 31A stores the second threshold T11, which is a criterion, as front setting information.

Note that the default value of the second threshold T11 can be set using a setting member such as a rotary switch before the start of automatic operation. Specifically, the second threshold T11 is set according to the operation amount of the setting member, the default value is set to a minimum value when the operation amount is smallest, and the default value is set to a maximum value when the operation amount is largest. The maximum value (T11 max) of the second threshold T11 may be determined by subtracting braking distance and fallback distance from the default value of monitor dimension L6 and then dividing it by prescribed travel speed, i.e., "T11 max = [default value of monitor dimension L6 - braking distance - fallback distance] / prescribed travel speed". The braking distance and the fallback distance are found via simulation, experimentation, and/or the like, and the prescribed travel speed is set according to agricultural work. A method of calculating the maximum value of the second threshold T11 is not limited.

According to the invention, the rear obstacle detecting device 31B includes a first time calculation unit <NUM> and a first obstacle determination unit <NUM>. The first time calculation unit <NUM> and the first obstacle determination unit <NUM> are each composed of electric circuit(s), electronic circuit(s), and/or the like provided in the rear obstacle detecting device 31B, program(s) stored in the rear obstacle detecting device 31B, and/or the like.

The first time calculation unit <NUM> calculates a detection time (first detection time) T1 that is a period of time for which the detected object M2 is located in the monitored area Q2. The first obstacle determination unit <NUM> determines the detected object M2 as an obstacle if the first detection time T1 calculated by the first time calculation unit <NUM> is equal to or greater than a first threshold T10, and determines the detected object M2 as not an obstacle if the first detection time T1 is less than the first threshold T10. Note that the rear obstacle detecting device 31B stores the first threshold T10 as a criterion. That is, the rear obstacle detecting device 31B stores the first threshold T10, which is a criterion, as rear setting information. Note that the default value of the first threshold T10 can be set using a setting member such as a rotary switch before the start of automatic operation. Specifically, the first threshold T10 is set according to the operation amount of the setting member, the default value is set to a minimum value when the operation amount is smallest, and the default value is set to a maximum value when the operation amount is largest.

<FIG> shows examples of the second detection time T2 that starts upon detection of the detected object M1 by the front obstacle detecting device 31A and the first detection time T1 that starts upon detection of the detected object M2 by the rear obstacle detecting device 31B.

As shown in <FIG>, assume that the detected object M1 entered the monitored area Q1 at a point in time P1. The second time calculation unit <NUM> calculates the second detection time T2 for which the detected object M1 is in the monitored area Q1. When the second detection time T2 has reached the second threshold T11, the second obstacle determination unit <NUM> determines the detected object M1 as an obstacle.

Assume that the detected object M2 entered the monitored area Q2 at a point in time P2. The first time calculation unit <NUM> calculates the first detection time T1 for which the detected object M2 is in the monitored area Q2. When the first detection time T1 has reached the first threshold T10, the first obstacle determination unit <NUM> determines the detected object M2 as an obstacle.

As illustrated in <FIG>, the tractor <NUM> includes a control device <NUM>. The control device <NUM> is composed of a CPU, storage unit(s) (such as RAM and/or ROM), and/or the like and performs various types of control regarding the tractor <NUM> on the basis of program(s) stored in the storage unit(s) and/or the like.

The control device <NUM> has connected thereto a state detecting device <NUM> to detect the driving state and/or the like of the tractor <NUM>. The state detecting device <NUM> is, for example, a crank sensor, a cam sensor, an engine rotation sensor, an accelerator pedal sensor, a vehicle speed sensor, an acceleration sensor, a steering angle sensor, a raising/lowering lever detection sensor, a PTO rotation detecting sensor, and/or the like. The control device <NUM> also has connected thereto the transmission <NUM>, a forward/rearward travel switching device <NUM>, a PTO clutch <NUM>, and a braking device <NUM>.

The state detecting device <NUM> is connected with the transmission <NUM>, the forward/rearward travel switching device <NUM>, the PTO clutch <NUM>, and the braking device <NUM> via an in-vehicle network N1 such as controller area network (CAN) and/or international standard ISO11783 (ISO-BUS). A control device 9a of the working device <NUM> is connected to the in-vehicle network N1. The control device 9a is composed of, for example, electric circuit(s), electronic circuit(s), and/or the like including a CPU, storage unit(s) (such as RAM and/or ROM), and/or the like, and controls the working device <NUM>.

The control device <NUM> controls a travelling system and a working system of the tractor <NUM>. For example, the control device <NUM> controls engine speed, vehicle speed, the angle of steering by the steering unit <NUM>, and/or the like on the basis of the state(s) detected by the state detecting device <NUM>. The control device <NUM> controls raising and lowering of the raising/lowering device, PTO rotation speed, and/or the like on the basis of the states(s) detected by the state detecting device <NUM>.

The control device <NUM> is configured to control automatic travel (perform automatic travel control) of the tractor <NUM> (vehicle body <NUM>). The control device <NUM> is configured to switch between an automatic travel mode and a manual travel mode. In the automatic travel mode, the control device <NUM> causes the vehicle body <NUM> to automatically travel along a predetermined travel route. The control device <NUM> sets the position and the degree of opening of the control valve <NUM> so that the position of the vehicle body <NUM> that is traveling (the position detected by the position detecting device <NUM>) matches a predetermined travel route (travel path), that is, the vehicle body <NUM> matches the travel route. In other words, in the automatic travel mode, the control device <NUM> sets the direction and amount of movement of the steering cylinder <NUM> (steering direction and steering angle of the front wheels 3F) so that the position of the traveling tractor <NUM> matches the travel route.

Specifically, in the automatic travel mode, the control device <NUM> compares the position of the vehicle body <NUM> that is traveling and the position indicated by the travel route (planned travel position), and, if the position of the vehicle body <NUM> that is traveling matches the planned travel position, the control device <NUM> maintains the angle and direction of steering by the steering wheel 11a of the steering unit <NUM> (the steering angle and the steering direction of the front wheels 3F) without changing them (maintains the degree of opening and the position of the control valve <NUM> without changing them). If the position of the vehicle body <NUM> that is traveling does not match the planned travel position, the control device <NUM> changes the angle and/or direction of steering by the steering wheel 11a of the steering unit <NUM> (changes the degree of opening and/or the position of the control valve <NUM>) so that the deviation (amount of deviation) between the position of the vehicle body <NUM> that is traveling and the planned travel position is zero.

Note that, although the control device <NUM> changes the angle of steering by the steering unit <NUM> on the basis of the deviation between the position of the vehicle body <NUM> that is traveling and the planned travel position in the automatic travel control in the present embodiment, the control device <NUM> may, in the case where the direction of the travel route and the travel direction of the tractor <NUM> (vehicle body <NUM>) (vehicle body heading direction) differ from each other, set the steering angle so that the vehicle body heading direction matches the direction of the travel route. The control device <NUM> may set, in the automatic travel control, the final steering angle for the automatic travel control on the basis of a steering angle determined based on the deviation (deviation in position) and a steering angle determined based on the deviation in direction. The steering angle may be set by a method differing from the above-described method of setting the steering angle in the automatic travel control.

The control device <NUM> may control, in the automatic travel control, the rotation speed of the traveling device <NUM> (i.e., the front wheels 3F and/or the rear wheel 3R) so that the actual speed of the tractor <NUM> (vehicle body <NUM>) matches a vehicle speed corresponding to a predetermined travel route.

Furthermore, the control device <NUM> controls automatic travel on the basis of a result of obstacle detection by the obstacle detecting devices <NUM>. For example, the control device <NUM> continues automatic travel if the obstacle detecting device(s) <NUM> has/have detected no obstacles, and stops the automatic travel if the obstacle detecting device(s) <NUM> has/have detected obstacle(s). More specifically, if the obstacle detecting device(s) <NUM> has/have detected an obstacle, the control device <NUM> stops the automatic travel by stopping the tractor <NUM> from traveling if the distance between the obstacle and the tractor <NUM> is equal to or less than a predetermined distance.

Specifically, if the obstacle detecting device(s) <NUM> has/have detected an obstacle, the control device <NUM> controls the operation of the transmission <NUM>, the forward/rearward travel switching device <NUM>, the PTO clutch <NUM>, and the braking device <NUM>. Specifically, the control device <NUM> reduces vehicle speed by changing the speed stage of the transmission <NUM> to a lower speed stage. Furthermore, the control device <NUM> switches the state of the forward/rearward travel switching device <NUM> to a neutral state and activates the braking device <NUM>. This stops the automatic travel of the tractor <NUM>. Furthermore, the control device <NUM> switches the PTO clutch <NUM> into an OFF state to block the transmission of power from the PTO shaft of the tractor <NUM> to the working device <NUM>. This stops the working device <NUM> from being driven.

As illustrated in <FIG>, the control device <NUM> includes a setting change unit <NUM>. The setting change unit <NUM> is composed of electric circuit(s), electronic circuit(s), program(s), and/or the like provided in the control device <NUM>. The setting change unit <NUM> is configured to change rear setting information for the rear obstacle detecting device 31B.

The setting change unit <NUM> changes the size of the monitored area Q2 according to the travel speed of the vehicle body <NUM>. Specifically, upon initiation of automatic travel under the automatic travel control by the control device <NUM>, the setting change unit <NUM> refers to the vehicle speed (travel speed) of the vehicle body <NUM> detected by the vehicle speed sensor. When the travel speed has exceeded a travel speed threshold, the setting change unit <NUM> changes the monitor dimension L10 so that the monitor dimension L10 is greater than the default value (reference monitor dimension). That is, the setting change unit <NUM> makes the monitor dimension L10 greater than the default value (reference monitor dimension) to make the size of the monitored area Q2 lager than the reference monitored area.

On the contrary, if the travel speed has become less than the travel speed threshold, the setting change unit <NUM> changes the monitor dimension L10 so that the monitor dimension L10 is less than the default value (reference monitor dimension). That is, the setting change unit <NUM> makes the monitor dimension L10 less than the default value (reference monitor dimension) to make the size of the monitored area Q2 smaller than the reference monitored area. The travel speed threshold is a value for the setting change unit <NUM> to determine whether the vehicle speed is high speed or low speed. The travel speed threshold may be pre-stored in the control device <NUM> and may be changed using a rotary switch or the like, and there is no limitation.

Note that the monitor dimension L10 may be changed (increased or reduced) according to the travel speed. For example, the setting change unit <NUM> gradually increases the monitor dimension L10 as the travel speed increases and gradually reduces the monitor dimension L10 as the trave speed decreases, in proportion to the travel speed. With regard to changing the monitored area Q2 and/or the like by the setting change unit <NUM>, the monitored area Q2 and/or the like may be changed according to the travel speed of the vehicle body <NUM> during backward travel.

The setting change unit <NUM> changes the monitor dimension(s) L10 and/or L11 according to the working device <NUM> linked to the vehicle body <NUM>. Specifically, upon linkage of the working device <NUM> to the vehicle body <NUM>, the setting change unit <NUM> acquires a machine width W10 and a machine length L20 of the working device <NUM> from the control device 9a of the working device <NUM> via the in-vehicle network N1. As illustrated in <FIG>, if the default value (reference monitor dimension) of the monitor dimension L11 is less than the machine width W10 of the working device <NUM>, as illustrated in <FIG>, the setting change unit <NUM> makes the monitor dimension L11 greater than the machine width W10 of the working device <NUM>.

As illustrated in <FIG>, when the monitored area Q2 is defined by the default values (reference monitor dimensions) of the monitor dimensions L10 and L11, if a rear edge Q2a of the monitored area Q2 is located forward of a rear edge 9b of the working device <NUM> and one or both of opposite boundaries Q2b of the monitored area Q2 in the width direction is/are located inward of corresponding one(s) of opposite ends 9c of the rear edge 9b of the working device <NUM> in the width direction, as illustrated in <FIG>, the setting change unit <NUM> makes the monitor dimensions L10 and L11 greater than the default values (reference monitor dimensions) so that the rear edge Q2a of the monitored area Q2 is located rearward of the rear edge 9b of the working device <NUM> and the opposite boundaries Q2b of the monitored area Q2 in the width direction are located outward of the respective opposite ends 9c of the rear edge 9b of the working device <NUM> in the width direction. In the present embodiment, the front edge of the working device <NUM> can be detected by the front obstacle detecting devices 31A. Furthermore, by extending the monitor dimension(s) L3 of the front obstacle detecting device(s) 31A in a direction, it is possible to make a monitored area Ha1 and the working device <NUM> overlap each other.

Note that, although a method in which the setting change unit <NUM> acquires the machine width W10 of the working device <NUM> via the in-vehicle network N1 is discussed in the foregoing embodiment, the setting change unit <NUM> may cause a display device <NUM> (see <FIG>) of the tractor <NUM> to display an input screen for input of the machine width W10 and the machine length L20 of the working device <NUM> and acquire the machine width W10 of the working device <NUM> inputted into the input screen.

The setting change unit <NUM> changes criteria (the height threshold H4, the width threshold W4, and the first threshold T10) based on which the detected object M2 is determined as an obstacle. For example, in the case where work is work involving dust formation etc. such as spreading work (fertilizer spreading work or agent spreading work) or cultivating work, the setting change unit <NUM> makes the height threshold H4 and the width threshold W4 smaller than the default values. In the case where the work is other than the spreading work (fertilizer spreading work or agent spreading work) and cultivating work, the setting change unit <NUM> sets the height threshold H4 and the width threshold W4 to the default values.

As illustrated in <FIG>, the setting change unit <NUM> causes a settings screen J1 in which work (agricultural work) is set to be displayed. The settings screen J1 displays a plurality of types of agricultural work. When fertilizer spreading work, agent spreading work, or cultivating work is selected in the settings screen J1, the height threshold H4 and the width threshold W4 are made smaller than the default values. When agricultural work other than fertilizer spreading work, agent spreading work, and cultivating work is selected, the height threshold H4 and the width threshold W4 are set to the default values. Alternatively, in the case where a working device <NUM> for fertilizer spreading work, agent spreading work, or cultivating work is linked to the vehicle body <NUM>, the setting change unit <NUM> makes the height threshold H4 and the width threshold W4 smaller than the default values, and, in the case where a working device <NUM> for work other than fertilizer spreading work, agent spreading work, and cultivating work is linked to the vehicle body <NUM>, the setting change unit <NUM> sets the height threshold H4 and the width threshold W4 to the default values.

Although the height threshold H4 and the width threshold W4 are changed according to either agricultural work or the working device <NUM> in the foregoing embodiment, an elapsed time (first threshold T10) for determination of the detected object M2 as an obstacle may be changed. In such a case, when fertilizer spreading work, agent spreading work, or cultivating work is selected in the settings screen J1, the setting change unit <NUM> sets the first threshold T10 to the maximum value, and, when agricultural work other than fertilizer spreading work, agent spreading work, and cultivating work is selected, the setting change unit <NUM> sets the first threshold T10 to the default value. Alternatively, the setting change unit <NUM> sets the first threshold T10 to the maximum value and, when a working device <NUM> for work other than fertilizer spreading work, agent spreading work, and cultivating work is linked to the vehicle body <NUM>, the setting change unit <NUM> sets the first threshold T10 to the default value.

The setting change unit <NUM> is configured to also change the front setting information for the front obstacle detecting devices 31A.

The setting change unit <NUM> changes the size of each monitored area Q1 according to the travel speed of the vehicle body <NUM>. Specifically, when the vehicle speed (travel speed) of the vehicle body <NUM> detected by the vehicle speed sensor has exceeded a travel speed threshold, the setting change unit <NUM> changes the monitor dimension L6 so that the monitor dimension L6 is greater than the default value (reference monitor dimension). That is, the setting change unit <NUM> makes the monitor dimension L6 greater than the default value (reference monitor dimension) to make the size of the monitored area Q1 larger than the reference monitored area. On the contrary, if the travel speed has become less than the travel speed threshold, the setting change unit <NUM> changes the monitor dimension L6 so that the monitor dimension L6 is less than the default value (reference monitor dimension). That is, the setting change unit <NUM> makes the monitor dimension L6 less than the default value (reference monitor dimension) to make the size of the monitored area Q1 smaller than the reference monitored area.

Note that the monitor dimension L6 may be changed (increased or reduced) according to the travel speed. For example, the setting change unit <NUM> gradually increases the monitor dimension L6 as the travel speed increases and gradually reduces the monitor dimension L6 as the trave speed decreases, in proportion to the travel speed.

The setting change unit <NUM> changes the monitor dimension L5 according to the working device <NUM> linked to the vehicle body <NUM>. Specifically, if the default value (reference monitor dimension) of the monitor dimension L5 is less than the machine width W10 of the working device <NUM>, the setting change unit <NUM> makes the monitor dimension L5 greater than the machine width W10 of the working device <NUM>.

The setting change unit <NUM> changes criteria (the height threshold H2, the width threshold W2, and the second threshold T11) based on which the detected object M1 is determined as an obstacle. Similar to the rear obstacle detecting device 31B, in the case where work is spreading work (fertilizer spreading work or agent spreading work), cultivating work, or the like, the setting change unit <NUM> makes the height threshold H2 and the width threshold W2 smaller than the default values. In the case where the work is other than spreading work (fertilizer spreading work or agent spreading work) and cultivating work, the setting change unit <NUM> sets the height threshold H2 and the width threshold W2 to the default values. Note that the default values of the height threshold H2 and the width threshold W2 corresponding to the detected object M1 are set to smaller values than the height threshold H4 and the width threshold W4 corresponding to the detected obj ect M2.

Although the height threshold H2 and the width threshold W2 are changed according to either agricultural work or the working device <NUM> in the foregoing embodiment, an elapsed time (first threshold T11) for determination of the detected object M1 as an obstacle may be changed.

When fertilizer spreading work, agent spreading work, or cultivating work is selected, the setting change unit <NUM> makes the first threshold T11 smaller than a default value, and, when agricultural work other than fertilizer spreading work, agent spreading work, and cultivating work is selected, the setting change unit <NUM> sets the first threshold T11 to the default value. Alternatively, when a working device <NUM> for fertilizer spreading work, agent spreading work, or cultivating work is linked to the vehicle body <NUM>, the setting change unit <NUM> makes the second threshold T11 smaller than the default value, and when a working device <NUM> for work other than fertilizer spreading work, agent spreading work, and cultivating work is linked to the vehicle body <NUM>, the setting change unit <NUM> sets the second threshold T11 to the default value. Alternatively, the setting change unit <NUM> may make the monitor dimension L6 smaller than the default value when fertilizer spreading work, agent spreading work, or cultivating work is selected.

As has been described, the front setting information and the rear setting information may each be changed by the setting change unit <NUM> in accordance and in conjunction with travel speed, work (agricultural work), and the type of working device <NUM> (which are herein collectively referred to as "change conditions") or may be changed independently in accordance with the travel speed, work (agricultural work), or the type of working device <NUM>. As illustrated in <FIG>, the display device <NUM> may display a settings screen J2, and settings regarding changes to the front setting information and the rear setting information may be performed by operating the display device <NUM> on the settings screen J2.

For example, the following may be included or performed: in a first section K1 of the settings screen J2, "allow changes (from default value(s) during automatic travel)" or "don't allow changes (from default value(s) during automatic travel)" can be selected for the front setting information and for the rear setting information. In the case of "allow changes" to the front setting information and to the rear setting information in the first section K1, as described earlier, setting information can be changed by the setting change unit <NUM> according to travel speed, work (agricultural work), the type of the working device <NUM>, and/or the like. On the contrary, in the case of "don't allow changes" to the front setting information and to the rear setting information in a second column, changes are not made by the setting change unit <NUM>, and default values are maintained during automatic travel.

The following may be included or performed: in a second section K2 of the settings screen J2, one or more items (the monitored areas Q1 and Q2, the height thresholds H2 and H4, the width thresholds W2 and W4, the first threshold T10, and/or the second threshold T11) to be changed when changes to the setting information are allowed can be selected. In such a case, piece(s) of the setting information (the front setting information and/or the rear setting information) corresponding to the item(s) selected in the second section K2 are changed.

The following may be included or performed: in a third section K3 of the settings screen J2, each of the change conditions [travel speed, work (agricultural work), and the type of working device <NUM>] can be selected. In such a case, setting information (the front setting information and/or the rear setting information) is changed when the change condition(s) [travel speed, work (agricultural work), and/or the type of working device <NUM>] corresponding to the item(s) selected in the third section K3 is/are satisfied during automatic travel.

As such, whether or not to allow changes to the front setting information and the rear setting information can be selected, and, when the changes are allowed, item(s) to be changed can be selected from a plurality of items, and change conditions can also be selected. This makes it possible to achieve settings corresponding to various situations in agricultural work. For example, changes can be made not only based on agricultural work itself but also based on the state of an agricultural filed on which agricultural work is to be done (e.g., soft soil, slope), the size of the tractor <NUM>, the size of the working device <NUM>, weather, and/or the like.

A working vehicle <NUM> includes a vehicle body <NUM>, a linkage <NUM> provided on the vehicle body <NUM> and configured to link a working device <NUM>, a control device <NUM> to cause the vehicle body <NUM> to perform automatic travel, a rear obstacle detecting device 31B configured to detect obstacles behind the vehicle body <NUM>, and a setting change unit <NUM> configured to change rear setting information regarding obstacle detection performed by the rear obstacle detecting device 31B. With this, because the rear setting information for the rear obstacle detecting device 31B provided at the rear of the vehicle body <NUM> can be changed by the setting change unit <NUM>, it is possible to improve the accuracy of obstacle detection according to work done by the working device <NUM> and/or the travel (forward travel or rearward travel) of the vehicle body <NUM>, and possible to do work appropriately according to various situations. In particular, by changing information for detection of obstacles in an area rearward of the vehicle body, it is possible to improve workability while achieving efficient automatic travel.

The rear setting information includes a size of a monitored area Q2 that is monitored for detecting the obstacles, and the setting change unit <NUM> changes the size of the monitored area Q2 according to a travel speed of the vehicle body <NUM>. This makes it possible to change the monitored area Q2 according to travel speed corresponding to the work done by the working device <NUM>. For example, in the case where work is done with the working device <NUM> at high speed, widening the monitored area Q2 makes it possible to quickly detect abnormalities during working while traveling rearward. On the contrary, in the case where work is done at low speed, narrowing the monitored area Q2 makes it possible to perform monitoring with higher accuracy. Furthermore, in the case where work is done at low speed, by narrowing the monitored area Q2, it is possible for the working device <NUM> to do work even in peripheral areas of the agricultural field and possible to increase work area.

The setting change unit <NUM> changes a size of the monitored area Q2 according to the working device <NUM> linked to the vehicle body <NUM>. With this, blind spots that may form at the rear depending on the size of the working device <NUM> are eliminated or minimized and, also in view of the condition of the ground after work that differs depending on the size of the working device <NUM>, improved monitoring is achieved during work.

The rear setting information includes a size of an object M2 to be determined as an obstacle, and the setting change unit <NUM> sets, according to work or the working device <NUM>, the size of the object M2 to be determined as an obstacle. This makes it possible to reduce false detection of obstacles in the case of work that relatively involves dust formation such as fertilizer spreading work, agent spreading work, or cultivating work, and possible to improve the accuracy of obstacle detection in the case of work that does not involve dust formation.

The rear obstacle detecting device 31B includes a first time calculation unit <NUM> to calculate a detection time that is a period of time for which an obj ect M2 located in the monitored area Q2 monitored for detecting the obstacles is detected, and a first obstacle determination unit <NUM> to determine the object M1, M2 as an obstacle if the detection time calculated by the first time calculation unit <NUM> is equal to or greater than a first threshold. This makes it possible to perform detection in consideration of the conditions in which the object M1 stays within the monitored area Q2.

The setting change unit <NUM> changes the first threshold. With this, by changing a threshold relating to the period of time for which the object M2 stays within the monitored area Q2, it is possible to reduce false detection of obstacles in the case of work that relatively involves dust formation such as fertilizer spreading work, agent spreading work, or cultivating work, and possible to improve the accuracy of obstacle detection in the case of work that does not involve dust formation.

The working vehicle <NUM> further includes a front obstacle detecting device 31A configured to detect obstacles in front of the vehicle body <NUM>, and the setting change unit <NUM> changes front setting information regarding obstacle detection performed by the front obstacle detecting device 31A. With this, because it is possible to change the front setting information for the front obstacle detecting device 31A, it is possible to improve the accuracy of obstacle detection according to work done by the working device <NUM> and/or the travel (forward travel or rearward travel) of the vehicle body <NUM>, and possible to do work appropriately according to various situations. In particular, the combination of the front setting information for the front of the vehicle body and the rear setting information makes it possible to perform obstacle detection with higher accuracy during mixed work such as work in which forward travel and rearward travel are repeated.

Claim 1:
A working vehicle (<NUM>) comprising:
a vehicle body (<NUM>);
a linkage (<NUM>) provided on the vehicle body (<NUM>) and configured to link a working device (<NUM>);
a control device (<NUM>) configured to cause the vehicle body (<NUM>) to perform automatic travel;
a rear obstacle detecting device (31B) configured to detect obstacles behind the vehicle body (<NUM>) during the automatic travel; and
a setting change unit (<NUM>) configured to change rear setting information regarding obstacle detection performed by the rear obstacle detecting device (31B), wherein:
the working vehicle (<NUM>) is configured to perform work by the working device (<NUM>) during the automatic travel,
characterized in that
the rear setting information includes a size of an obj ect to be determined as an obstacle,
the setting change unit (<NUM>) is configured to set,
according to the work or a type of the working device (<NUM>), the size of the object to be determined as an obstacle, and
the rear obstacle detecting device (31B) includes:
a first time calculation unit (<NUM>) configured to calculate a detection time (T1) that is a period of time for which an object (M2) located in a monitored area (Q2) monitored for detecting the obstacles is detected; and
a first obstacle determination unit (<NUM>) configured to determine the object (M2) as an obstacle if the detection time (T1) calculated by the first time calculation unit (<NUM>) is equal to or greater than a first threshold (T10).