Patent Description:
The above-described automatic travel system makes a work vehicle automatically travel along a scheduled travel path including multiple travel paths generated in advance, based on positioning information of the work vehicle, which is acquired by use of a satellite positioning system or the like (see, for example, Patent Literature <NUM>).

For example, in a case where the work vehicle is at a position outside the scheduled travel path, the system described in Patent Literature <NUM> searches for a travel path that the work vehicle can enter, in order to make the work vehicle enter the travel path and restart the automatic traveling. For the searching of a travel path, a search area is set in the travel direction (front side) of the work vehicle by use of position information and direction information of the work vehicle, so that, out of the travel paths existing inside the search area, the travel path at the nearest position from the work vehicle is selected as the travel path that the work vehicle can enter (see <CIT>).

In the system described in the above-described Patent Literature <NUM>, since the search area is set on the front side of the work vehicle, a travel path that the work vehicle can enter is searched while the work vehicle travels forward. However, for example, there is also a case in which the travel path at the nearest position from the work vehicle exists on the rear side of the work vehicle. In this case, the work vehicle enters a travel path other than the travel path at the nearest position from the work vehicle. Therefore, if the search area is only set on the front side of the work vehicle, the work vehicle cannot enter a desired travel path based on a demand from the user or the like, so that the work cannot be started from the desired travel path.

In view of this situation, the main object of the present invention is to provide an automatic travel system capable of entering a desired travel path of a scheduled travel path including multiple travel paths so that the work can be started from the desired travel path.

The first characteristic configuration of the present invention is to include: a path generation unit that generates a scheduled travel path including multiple travel paths on which a work vehicle is made to perform automatic traveling; an automatic travel control unit that is capable of making the work vehicle perform the automatic traveling along the scheduled travel path; an information acquisition unit that acquires position information and direction information of the work vehicle; and a specifying unit that specifies an automatic traveling candidate path on which the work vehicle can start automatically traveling before the automatic traveling is started by the work vehicle; and that the specifying unit sets candidate specification areas on a front side and a rear side of the work vehicle, based on the position information and direction information of the work vehicle acquired by the information acquisition unit, and specifies a travel path included in the candidate specification areas as the automatic traveling candidate path out of the multiple travel paths.

According to the present configuration, the specifying unit sets the candidate specification areas not only on the front side but also on the rear side of the work vehicle, based on the position information and direction information of the work vehicle. It is also possible for the specifying unit not only to specify the travel path included in the front-side candidate specification area as the automatic traveling candidate path but also to specify the travel path included in the rear-side candidate specification area as the automatic traveling candidate path. As a result, in a case where the desired travel path according to a demand from the user or the like or the work situation is included in the front-side candidate specification area, it is possible to enter the automatic traveling candidate path included in the front-side candidate specification area and start the work, and, in a case where the desired travel path is included in the rear-side candidate specification area, it is possible to enter the automatic traveling candidate path included in the rear-side candidate specification area and start the work. Therefore, in a scheduled travel path including multiple travel paths, it is possible to enter a desired travel path and start a work from the desired travel path.

The second characteristic configuration of the present invention is that: in a case where the specifying unit specifies a travel path included in a front-side candidate specification area as the automatic traveling candidate path, the automatic travel control unit makes the work vehicle travel forward so as to enter the automatic traveling candidate path; and, in a case where the specifying unit specifies a travel path included in a rear-side candidate specification area as the automatic traveling candidate path, the automatic travel control unit makes the work vehicle travel backward so as to enter the automatic traveling candidate path.

According to the present configuration, since the work vehicle is made to travel forward to enter the automatic traveling candidate path in a case where the travel path included in the front-side candidate specification area is specified as the automatic traveling candidate path, it is possible to smoothly enter the automatic traveling candidate path. Since the work vehicle is made to travel backward to enter the automatic traveling candidate path in a case where the travel path included in the rear-side candidate specification area is specified as the automatic traveling candidate path, it is possible to smoothly enter the automatic traveling candidate path. In this way, since it is possible to smoothly enter the automatic traveling candidate path while switching the forward traveling and reverse traveling of the work vehicle according to the specified situation of the automatic traveling candidate path, the automatic traveling from the automatic traveling candidate path can be efficiently and properly started.

The third characteristic configuration of the present invention is to include a display unit that displays the travel path included in the candidate specification areas, and that the display unit displays the travel path included in the front-side candidate specification area and the travel path included in the rear-side candidate specification area in a distinguishable manner.

According to the present configuration, since the display unit displays the travel path included in the front-side candidate specification area and the travel path included in the rear-side candidate specification area in a distinguishable manner, it is possible for the user or the like to easily recognize whether the specified automatic traveling candidate path is included in the front-side candidate specification area or is included in the rear-side candidate specification area. As a result, it is possible for the user or the like to compare the automatic traveling candidate path included in the front-side candidate specification area and the automatic traveling candidate path included in the rear-side candidate specification area and easily recognize which of them suits the demand.

The fourth characteristic configuration of the present invention is to include an area selection unit that is capable of selecting whether the candidate specification area is set on the front side of the work vehicle or the candidate specification area is set on the rear side of the work vehicle, and that the specifying unit sets the candidate specification area on the front side of the work vehicle or on the rear side of the work vehicle according to a selection state of the area selection unit.

According to the present configuration, for setting a candidate specification area, it is possible for the area selection unit to select whether the candidate specification area is set on the front side of the work vehicle or is set on the rear side of the work vehicle according to the demand from the user or the like, the work situation, etc. As a result, since it is possible to specify a proper automatic traveling candidate path according to the demand from the user or the like, the work situation, etc., it is possible to start the work from a proper automatic traveling candidate path, so that the convenience for the user or the like and the work efficiency can be improved.

Embodiments of the automatic travel system according to the present invention will be explained, based on the drawings.

Although the tractor <NUM> is employed as the work vehicle in this automatic travel system as illustrated in <FIG>, it is possible that a riding-type work vehicle, such as a riding-type rice transplanter, a combine, a riding-type mower, a wheel loader, or a snowplow, or an unmanned work vehicle, such as an unmanned mower, is employed instead of a tractor.

As illustrated in <FIG> and <FIG>, this automatic travel system includes an automatic travel unit <NUM>, which is mounted on the tractor <NUM>, and a portable communication terminal <NUM>, to which a communication setting for enabling communication with the automatic travel unit <NUM> is provided. As the portable communication terminal <NUM>, it is possible to adopt a tablet-type personal computer, smartphone, or the like, which is provided with a display unit <NUM> (for example, a liquid crystal panel) to which a touch-operation can be performed.

The tractor <NUM> is provided with a travel vehicle body <NUM> including the left and right drivable front wheels <NUM>, which function as steering wheels, and the left and right drivable rear wheels <NUM>. A bonnet <NUM> is arranged in the front of the travel vehicle body <NUM>, and an electronically-controlled diesel engine (hereinafter referred to as an engine) <NUM> having a common rail system is equipped in the bonnet <NUM>. Behind the bonnet <NUM> of the travel vehicle body <NUM>, there is provided a cabin <NUM>, which forms a boarding-type driving section.

It is possible to configure the tractor <NUM> as a rotary cultivation model by connecting a rotary cultivation device, which is an example of the work device <NUM>, to the rear part of the travel vehicle body <NUM> via a three-point link mechanism <NUM> in such a manner that the rotary cultivation device can move up and down and roll. Instead of a rotary cultivation device, it is possible to connect a work device <NUM> such as a plow, a seeding device, or a spraying device, to the rear part of the tractor <NUM>.

As illustrated in <FIG>, the tractor <NUM> includes an electronically-controlled transmission <NUM> for changing gears for the power from the engine <NUM>, a full-hydraulic power steering mechanism <NUM> for steering the left and right front wheels <NUM>, left and right side brakes (not illustrated in the drawing) for putting brakes on the left and right rear wheels <NUM>, an electronically-controlled brake operation mechanism <NUM> for enabling a hydraulic operation of the left and right side brakes, a work clutch (not illustrated in the drawing) for engaging and disengaging power transmission to the work device <NUM> such as a rotary cultivation device, an electronically-controlled clutch operation mechanism <NUM> for enabling a hydraulic operation of the work clutch, an electro-hydraulically-controlled raising/lowering drive mechanism <NUM> for driving the work device <NUM> such as a rotary cultivation device to be raised and lowered, an onboard electronic control unit <NUM> having various kinds of control programs, etc., related to automatic traveling of the tractor <NUM> or the like, a vehicle speed sensor <NUM> for detecting a vehicle speed of the tractor <NUM>, a steering angle sensor <NUM> for detecting steering angles of the front wheels <NUM>, a positioning unit <NUM> for measuring the current position and the current direction of the tractor <NUM>, etc..

Note that it is also possible that an electronically-controlled gasoline engine including an electronic governor is adopted for the engine <NUM>. For the transmission <NUM>, it is possible to adopt a hydro-mechanical continuously-variable transmission (HMT), a hydro-static continuously-variable transmission (HST), a belt-type continuously-variable transmission, or the like. For the power steering mechanism <NUM>, it is also possible to adopt an electric power steering mechanism <NUM> including an electric motor or the like.

As illustrated in <FIG>, a steering wheel <NUM> for enabling manual steering of the left and right front wheels <NUM> via the power steering mechanism <NUM> (see <FIG>), a driver's seat <NUM> for a passenger, a touchscreen-type display unit, various kinds of operation tools, etc., are provided inside the cabin <NUM>.

As illustrated in <FIG>, the onboard electronic control unit <NUM> includes a transmission control unit <NUM> for controlling operation of the transmission <NUM>, a braking control unit <NUM> for controlling operation of the left and right side brakes, a work device control unit <NUM> for controlling operation of the work device <NUM> such as a rotary cultivation device, a steering angle setting unit <NUM> for setting target steering angles of the left and right front wheels <NUM> at the time of automatic traveling and outputting the target steering angles to the power steering mechanism <NUM>, a non-volatile onboard storage unit <NUM> for storing a target travel path P (for example, see <FIG>) that is generated in advance for automatic traveling or the like, etc..

As illustrated in <FIG>, the positioning unit <NUM> includes a satellite navigation device <NUM> for measuring the current position and the current direction of the tractor <NUM> by use of GPS (Global Positioning System), which is an example of a satellite positioning system (NSS/Navigation Satellite System), an inertial measurement device (IMU/Inertial Measurement Unit) <NUM> for measuring the posture, direction, etc., of the tractor <NUM> by use of a three-axis gyroscope and a three-direction acceleration sensor included therein, etc. The positioning unit <NUM> acquires the current position (position information) of the tractor <NUM>, and the inertial measurement device <NUM> acquires direction information of the tractor <NUM>, so that the positioning unit <NUM> and the inertial measurement device <NUM> correspond to an information acquisition unit. The positioning methods using GPS include DGPS (Differential GPS), RTK-GPS (Real Time Kinematic GPS), etc. In the present embodiment, RTK-GPS, which is suitable for positioning of a movable object, is adopted. Therefore, as illustrated in <FIG> and <FIG>, a reference station <NUM> that enables positioning by use of RTK-GPS is installed at a given position in the vicinity of the field.

As illustrated in <FIG>, the tractor <NUM> and the reference station <NUM> respectively include positioning antennas <NUM> and <NUM> for receiving radio waves transmitted from positioning satellites <NUM> (see <FIG>), communication modules <NUM> and <NUM> for enabling wireless communication of various kinds of information including positioning information between the tractor <NUM> and the reference station <NUM>, etc. Accordingly, the satellite navigation device <NUM> is capable of measuring the current position and the current direction of the tractor <NUM> with high precision, based on positioning information acquired by the positioning antenna <NUM> on the tractor side receiving radio waves from the positioning satellites <NUM> and positioning information acquired by the positioning antenna <NUM> on the reference station side receiving radio waves from the positioning satellites <NUM>. In addition, since the positioning unit <NUM> includes the satellite navigation device <NUM> and the inertial measurement device <NUM>, it is possible to measure the current position, current direction, and attitude angles (yaw angle, roll angle, pitch angle) of the tractor <NUM> with high precision.

The positioning antenna <NUM>, the communication module <NUM>, and the inertial measurement device <NUM> provided in the tractor <NUM> are housed in the antenna unit <NUM>, as illustrated in <FIG>. The antenna unit <NUM> is arranged at an upper position on the front side of the cabin <NUM>.

As illustrated in <FIG>, the portable communication terminal <NUM> includes a terminal electronic control unit <NUM> provided with various kinds of control programs for controlling the operation of the display unit <NUM>, etc., a communication module <NUM> that enables wireless communication of various kinds of information, which includes positioning information, with the communication module <NUM> on the tractor side, etc. The terminal electronic control unit <NUM> includes a travel path generation unit <NUM> that generates a target travel path P (for example, see <FIG>) for making the tractor <NUM> automatically travel, a non-volatile terminal storage unit <NUM> in which various types of input information input by the user and the target travel path P generated by the travel path generation unit <NUM> are stored, etc..

For the travel path generation unit <NUM> to generate a target travel path P, the user or the like, such as a driver or an administrator, inputs vehicle body information such as the type and model of the work vehicle or the work device <NUM> in accordance with input guidance, which is displayed on the display unit <NUM> of the portable communication terminal <NUM> for setting the target travel path, and the input vehicle body information is stored in the terminal storage unit <NUM>. It is assumed that the work region S (see <FIG>) for which the target travel path P is generated is a field, and the terminal electronic control unit <NUM> of the portable communication terminal <NUM> acquires field information including the shape and location of the field and stores the field information in the terminal storage unit <NUM>.

For an explanation of the acquisition of the field information, the user or the like drives the tractor <NUM> to make the tractor <NUM> actually travel, so that the terminal electronic control unit <NUM> can acquire position information for specifying the shape, location, etc., of the field from the current position of the tractor <NUM>, which is acquired by the positioning unit <NUM>, etc. The terminal electronic control unit <NUM> specifies the shape and location of the field from the acquired position information and acquires the field information including the work region S, which is specified by the specified shape and location of the field. In the example illustrated in <FIG>, the work region S in a rectangular shape is specified.

In a case where the field information including the specified shape, location, etc., of the field is stored in the terminal storage unit <NUM>, the travel path generation unit <NUM> generates the target travel path P by use of the field information and the vehicle body information stored in the terminal storage unit <NUM>.

As illustrated in <FIG>, the travel path generation unit <NUM> segments the work region S to set the central region R1 and the outer peripheral region R2. The central region R1, which is set to be the central part of the work region S, is a reciprocating work region in which the tractor <NUM> is made to automatically travel in a reciprocating direction to perform a predetermined work (for example, a work such as cultivation). The outer peripheral region R2 is set around the central region R1. The travel path generation unit <NUM> calculates a space for turning traveling, which is required for making the tractor <NUM> perform turning traveling at the shore of the field, based on the front-rear width, left-right width, etc., of the tractor <NUM> and the turning radius included in the vehicle body information, for example. The travel path generation unit <NUM> segments the work region S into the central region R1 and the outer peripheral region R2, so as to ensure the calculated space, etc., in the outer periphery of the central region R1.

As illustrated in <FIG>, the travel path generation unit <NUM> generates the target travel path P (corresponding to a scheduled travel path) by use of the vehicle body information, the field information, etc. For example, the target travel path P includes multiple linear work paths P1 (corresponding to travel paths), which have the same straight travel distance in the central region R1 and are arranged and set in parallel with a constant distance corresponding to the work width, and connection paths P2 for connecting the start point and the end point of adjacent work paths P1. The multiple work paths P1 are paths in which the tractor <NUM> is made to travel straight to perform a predetermined work. The connection paths P2 are U-turn paths in which the tractor <NUM> is made to change travel direction by <NUM> degrees without performing the predetermined work, and a connection path P2 connects the end point of a work path P1 and the start point of the next work path P1 that is adjacent. Note that the target travel path P illustrated in <FIG> is merely an example, and the setting of the target travel path can be modified as appropriate.

The target travel path P, which is generated by the travel path generation unit <NUM>, can be displayed on the display unit <NUM> and is stored in the terminal storage unit <NUM> as path information that is associated with the vehicle body information, field information, etc. The path information includes the azimuths of the target travel path P, the set engine rotation speeds and target travel speeds, which are set according to the travel types of the tractor <NUM> on the target travel path P, etc..

In this way, in a case where the travel path generation unit <NUM> generates the target travel path P, the terminal electronic control unit <NUM> transfers the path information from the portable communication terminal <NUM> to the tractor <NUM>, so that the onboard electronic control unit <NUM> of the tractor <NUM> can acquire the path information. The onboard electronic control unit <NUM> can make the tractor <NUM> automatically travel along the target travel path P, based on the acquired path information, while acquiring the current position of itself (the current position of the tractor <NUM>) by use of the positioning unit <NUM>. The current position of the tractor <NUM>, which is acquired by the positioning unit <NUM>, is transmitted on a real-time basis (for example, every few milliseconds) from the tractor <NUM> to the portable communication terminal <NUM>, so that the portable communication terminal <NUM> is informed of the current position of the tractor <NUM>.

As for the transfer of path information, it is possible to transfer the entire path information at once from the terminal electronic control unit <NUM> to the onboard electronic control unit <NUM> at a stage before the tractor <NUM> starts automatic traveling. In addition, for example, it is also possible to divide the path information including the target travel path P into multiple path parts of a predetermined distance that requires a small information amount. In this case, at the stage before the tractor <NUM> starts automatic traveling, only the initial path part of the path information is transferred from the terminal electronic control unit <NUM> to the onboard electronic control unit <NUM>. After the automatic traveling starts, it is possible that each time the tractor <NUM> reaches a path acquisition point, which is set according to the information amount, etc., the path information only including the following path part corresponding to the point is transferred from the terminal electronic control unit <NUM> to the onboard electronic control unit <NUM>.

In a case of starting automatic traveling of the tractor <NUM>, for example, the user or the like moves the tractor <NUM> to the start point of the target travel path P, and, if various kinds of automatic traveling starting conditions are satisfied, the user operates the display unit <NUM> of the portable communication terminal <NUM> to provide an instruction for starting automatic traveling, so that the portable communication terminal <NUM> transmits the instruction for starting automatic traveling to the tractor <NUM>. As a result, when the onboard electronic control unit <NUM> of the tractor <NUM> receives the instruction for starting automatic traveling, the automatic travel control for making the tractor <NUM> automatically travel along the target travel path P while acquiring the current position of itself (the current position of the tractor <NUM>) by use of the positioning unit <NUM> is thereby started. The onboard electronic control unit <NUM> is configured as an automatic travel control unit that performs automatic travel control for making the tractor <NUM> automatically travel along the target travel path P in the work region S, based on positioning information of the tractor <NUM>, which is acquired by the positioning unit <NUM> by use of a satellite positioning system.

The automatic travel control includes automatic transmission control for automatically controlling operation of the transmission <NUM>, automatic braking control for automatically controlling operation of the brake operation mechanism <NUM>, automatic steering control for automatically steering the left and right front wheels <NUM>, working automatic control for automatically controlling operation of the work device <NUM> such as a rotary cultivation device, etc..

In the automatic transmission control, the transmission control unit <NUM> automatically controls operation of the transmission <NUM>, so that the target travel speed, which is set according to the travel type, etc., of the tractor <NUM> on the target travel path P, based on the path information of the target travel path P including the target travel speed, an output from the positioning unit <NUM>, and an output from the vehicle speed sensor <NUM>, is acquired as the vehicle speed of the tractor <NUM>.

In the automatic braking control, the braking control unit <NUM> automatically controls operation of the brake operation mechanism <NUM>, so that the left and right side brakes properly put a brake on the left and right rear wheels <NUM> in a braking region, which is included in the path information of the target travel path P, based on the target travel path P and an output from the positioning unit <NUM>.

In the automatic steering control, the steering angle setting unit <NUM> calculates and sets target steering angles of the left and right front wheels <NUM>, based on the path information of the target travel path P and an output from the positioning unit <NUM>, and the steering angle setting unit <NUM> outputs the set target steering angles to the power steering mechanism <NUM>, so that the tractor <NUM> automatically travels on the target travel path P. Based on the target steering angles and an output from the steering angle sensor <NUM>, the power steering mechanism <NUM> automatically steers the left and right front wheels <NUM>, so as to acquire the target steering angles as the steering angles of the left and right front wheels <NUM>.

In the working automatic control, based on the path information of the target travel path P and an output from the positioning unit <NUM>, the work device control unit <NUM> automatically controls operation of the clutch operation mechanism <NUM> and the raising/lowering drive mechanism <NUM>, so that the work device <NUM> starts a predetermined work (for example, a cultivation work) in response to the tractor <NUM> reaching a working start point such as the start point of a work path P1 (for example, see <FIG>) and the work device <NUM> stops the predetermined work in response to the tractor <NUM> reaching a working end point such as the end point of a work path P1 (for example, see <FIG>).

As described above, the automatic travel unit <NUM> of the tractor <NUM> is configured with the transmission <NUM>, the power steering mechanism <NUM>, the brake operation mechanism <NUM>, the clutch operation mechanism <NUM>, the raising/lowering drive mechanism <NUM>, the onboard electronic control unit <NUM>, the vehicle speed sensor <NUM>, the steering angle sensor <NUM>, the positioning unit <NUM>, the communication module <NUM>, etc..

In this embodiment, it is possible not only to make the tractor <NUM> automatically travel without a user or the like being in the cabin <NUM> but also to make the tractor <NUM> automatically travel with a user or the like being in the cabin <NUM>. Therefore, it is possible not only to make the tractor <NUM> automatically travel along a target travel path P by the automatic travel control performed by the onboard electronic control unit <NUM> without a user or the like being in the cabin <NUM> but also to make the tractor <NUM> automatically travel along a target travel path P by the automatic travel control performed by the onboard electronic control unit <NUM> even in a case where a user or the like is in the cabin <NUM>.

In the case where a user or the like is in the cabin <NUM>, it is possible to switch between an automatic travel state, in which the onboard electronic control unit <NUM> makes the tractor <NUM> automatically travel, and a manual travel state, in which the tractor <NUM> is made to travel based on driving by the user or the like. Therefore, it is possible to switch from the automatic travel state to the manual travel state while the tractor <NUM> is automatically traveling on the target travel path P in the automatic travel state, and, conversely, it is possible to switch from the manual travel state to the automatic travel state while the tractor <NUM> is traveling in the manual travel state. As for the switching between the manual travel state and the automatic travel state, for example, it is possible that a switching operation unit for switching between the automatic travel state and the manual travel state is provided in the vicinity of the driver's seat <NUM>, and it is also possible that such a switching operation unit is displayed on the display unit <NUM> of the portable communication terminal <NUM>. Furthermore, it is possible that, in a case where a user operates the steering wheel <NUM> during the automatic travel control performed by the onboard electronic control unit <NUM>, the automatic travel state is switched to the manual travel state.

As illustrated in <FIG> and <FIG>, the tractor <NUM> includes an obstacle detection system <NUM> for detecting an obstacle around the tractor <NUM> (travel vehicle body <NUM>) so as to avoid collision with the obstacle. The obstacle detection system <NUM> includes multiple LiDAR sensors <NUM> and <NUM> capable of three-dimensionally measuring the distance to a measurement target object by use of a laser, multiple sonar units <NUM> and <NUM> provided with sonars capable of measuring the distance to a measurement target object by use of ultrasonic waves, an obstacle detection unit <NUM>, and a collision avoidance control unit <NUM>.

It is assumed that the measurement target object, which is measured by the LiDAR sensors <NUM> and <NUM> and the sonar units <NUM> and <NUM>, is an object, person, or the like. As the LiDAR sensors <NUM> and <NUM>, a front LiDAR sensor <NUM> whose measurement target is the front side of the tractor <NUM> and a rear LiDAR sensor <NUM> whose measurement target is the rear side of the tractor <NUM> are provided. As the sonar units <NUM> and <NUM>, a right-side sonar unit <NUM> whose measurement target is the right side of the tractor <NUM> and a left-side sonar unit <NUM> whose measurement target is the left side of the tractor <NUM> are provided.

The obstacle detection unit <NUM> is configured to perform an obstacle detection process for detecting a measurement target object, such as an object or a person within a predetermined distance, as an obstacle, based on measurement information of the LiDAR sensors <NUM> and <NUM> and the sonar units <NUM> and <NUM>. The collision avoidance control unit <NUM> is configured to perform collision avoidance control for decelerating the tractor <NUM> or makes the tractor <NUM> stop traveling in a case where the obstacle detection unit <NUM> detects an obstacle. In the collision avoidance control, the collision avoidance control unit <NUM> not only decelerates the tractor <NUM> or makes the tractor <NUM> stop traveling but also activates the notification device <NUM>, such as a notification buzzer or a notification lamp, for notification that an obstacle exists. In the collision avoidance control, the collision avoidance control unit <NUM> communicates with the portable communication terminal <NUM> from the tractor <NUM> by use of the communication modules <NUM> and <NUM> to make the display unit <NUM> display the existence of the obstacle, so that it is possible to provide a notification that the obstacle exists.

The obstacle detection unit <NUM> repeatedly performs the obstacle detection process based on measurement information of the LiDAR sensors <NUM> and <NUM> and the sonar units <NUM> and <NUM> on a real-time basis, so as to properly detect obstacles such as objects and people. The collision avoidance control unit <NUM> performs collision avoidance control for avoiding a collision with an obstacle detected on a real-time basis.

The obstacle detection unit <NUM> and the collision avoidance control unit <NUM> are included in the onboard electronic control unit <NUM>. The onboard electronic control unit <NUM> is communicably connected to an electronic control unit for the engine, which is included in the common rail system, the LiDAR sensors <NUM> and <NUM>, the sonar units <NUM> and <NUM>, etc., via CAN (Controller Area Network).

In the automatic travel control of this automatic travel system, the onboard electronic control unit <NUM> is configured not only to make the tractor <NUM> automatically travel along a target travel path P from the start point to the goal point of the target travel path P but also to be able to execute a straight traveling mode, in which the tractor <NUM> is made to automatically travel along a work path P1 only on the multiple work paths P1 of a target travel path P.

In this straight traveling mode, although, on each of the multiple work paths P1, the onboard electronic control unit <NUM> makes the tractor <NUM> automatically travel along a work path P1 from the start point to the end point of the work path P1, the onboard electronic control unit <NUM> switches to the manual drive when the tractor <NUM> reaches the end point of the work path P1. Therefore, the turning traveling from the end point of the work path P1 to the start point of the next work path P1 is performed by the manual drive of the user or the like. On the target travel path P illustrated in <FIG>, the travel direction of the tractor <NUM> is defined as the predetermined direction for each of the multiple work paths P1, but, in the straight traveling mode, the travel direction in which the tractor <NUM> is made to automatically travel is not defined as a predetermined direction for each of the multiple work paths P1, so that it is also possible to make the tractor <NUM> automatically travel in the direction opposite to the arrow illustrated in <FIG>.

In a case of starting the automatic traveling of the tractor <NUM> in the straight traveling mode, it is possible to start the automatic traveling of the tractor <NUM> from any of the multiple work paths P1. As described above, since the travel path generation unit <NUM> generates the target travel path P including the multiple work paths P1, it is possible to specify any one of the multiple work paths P1 as the starting path P5 (see <FIG> and <FIG>) and start the automatic traveling from the specified starting path P5.

As illustrated in <FIG>, a specifying unit <NUM> that specifies an automatic traveling candidate path P4 (see <FIG> and <FIG>), on which the tractor <NUM> can start automatically traveling in the straight traveling mode before the automatic traveling is started by the tractor <NUM>, a starting path specifying unit <NUM> that specifies the starting path P5 (see <FIG> and <FIG>) from automatic traveling candidate paths P4 specified by the specifying unit <NUM>, etc., are included. The specifying unit <NUM> includes a candidate specification area setting unit <NUM> that sets candidate specification areas Q1 and Q2 (see <FIG> and <FIG>) on the front side and rear side of the tractor <NUM>, based on the acquired current position (position information) and direction information of the tractor <NUM>, so as to specify the work paths P1 included in the candidate specification areas Q1 and Q2 as the automatic traveling candidate paths P4. Since the current position (position information) of the tractor <NUM> is acquired by the positioning unit <NUM> and the direction information of the tractor <NUM> is acquired by the inertial measurement device <NUM>, the candidate specification area setting unit <NUM> is informed of the current position (position information) and direction information of the tractor <NUM> by communicating the current position (position information) and direction information of the tractor <NUM> by use of the communication modules <NUM> and <NUM>.

Hereinafter, with reference to the flowchart of <FIG>, an explanation is given of the case of starting automatic traveling in the straight traveling mode, based on <FIG> show a part of the display screen that is displayed on the display unit <NUM> of the portable communication terminal <NUM>, and the current position of the tractor <NUM> and multiple work paths P1 are therein displayed in a superimposed manner.

For example, the tractor <NUM> is positioned near the work path P1 from which the automatic traveling of the tractor <NUM> is desired to be started. Here, based on the operation state of the tractor <NUM>, the area selection unit <NUM> (see <FIG>) selects whether the candidate specification area Q1 (see <FIG>) is set on the front side of the tractor <NUM> or the candidate specification area Q2 (see <FIG>) is set on the rear side of the tractor <NUM> (Step #<NUM> of <FIG>). The operation state of the tractor <NUM> is, for example, the switch state of a forward-reverse travel switching operation unit (reverser), which is for switching between forward traveling and reverse traveling of the tractor <NUM>.

An explanation is given of the case in which the forward-reverse travel switching operation unit is switched to forward traveling. In this case, the area selection unit <NUM> selects a state in which the candidate specification area Q1 is set on the front side of the tractor <NUM>, and the candidate specification area setting unit <NUM> sets the front-side candidate specification area Q1 on the front side of the tractor <NUM> according to the state selected by the area selection unit <NUM> (Step #<NUM> in a case of FRONT SIDE in Step #<NUM> of <FIG>). As illustrated in <FIG>, the candidate specification area setting unit <NUM> sets the right-side front straight line T2 and left-side front straight line T3 that are obtained by rotating the front traveling straight line T1, which extends in the forward traveling direction (front-side straight traveling direction) of the tractor <NUM>, to the left and right by the rotation angle θ1 about the center, which is the current position of the tractor <NUM>. The area between the right-side front straight line T2 and the left-side front straight line T3 and in the range up to the set distance L from the current position of the tractor <NUM> is set as the front-side candidate specification area Q1 by the candidate specification area setting unit <NUM>.

In this way, the candidate specification area setting unit <NUM> sets the front-side candidate specification area Q1, which has a triangular shape extending in the front-side straight traveling direction of the tractor <NUM> with reference to the current position of the tractor <NUM>. The front-side candidate specification area Q1 is not limited to such a triangular-shaped area as described above, and various shapes such as a quadrangular shape and an arc shape can be applied, for example. The candidate specification area setting unit <NUM> can set the size of the front-side candidate specification area Q1 to be a predetermined size but can also modify the setting of the size of the front-side candidate specification area Q1 according to the situation of the tractor <NUM>, such as the current position of the tractor <NUM>.

When the front-side candidate specification area Q1 is set, the specifying unit <NUM> determines whether or not the orientation of the forward traveling direction of the tractor <NUM> is laterally facing a work path P1 with respect to the forward traveling direction (Step #<NUM> of <FIG>). As illustrated in <FIG>, for example, in a case where the angle ß formed by the left-side front straight line T3 (or the right-side front straight line T2) and the straight line along a work path P1 is a predetermined angle, the orientation of the forward traveling direction of the tractor <NUM> is laterally facing the work path P1. In this case, it is difficult to figure out from which work path P1 the automatic traveling of the tractor <NUM> is to be started, such as whether the tractor <NUM> is currently approaching the work path P1 from which the tractor <NUM> is to start the automatic traveling. Therefore, in a case where the orientation of the forward traveling direction of the tractor <NUM> is laterally facing a work path P1, the specifying unit <NUM> does not specify automatic traveling candidate paths P4 (in a case of Yes in Step #<NUM> of <FIG>).

If the orientation of the forward traveling direction of the tractor <NUM> is not laterally facing a work path P1, the specifying unit <NUM> determines whether or not a work path P1 exists inside the front-side candidate specification area Q1, so as to specify a work path P1 existing inside the front-side candidate specification area Q1 as an automatic traveling candidate path P4 (Step #<NUM> in a case of No in Step #<NUM> and Yes in Step #<NUM> of <FIG>). If one work path P1 exists inside the front-side candidate specification area Q1, the specifying unit <NUM> specifies the one work path P1 as the automatic traveling candidate path P4. As illustrated in <FIG>, if multiple work paths P1 exist inside the front-side candidate specification area Q1, the specifying unit <NUM> specifies the multiple work paths P1 (the four work paths P1, that is, the fourth to seventh work paths P1 from the left in <FIG>) as the automatic traveling candidate paths P4.

It is possible for the terminal electronic control unit <NUM> to display the automatic traveling candidate paths P4 specified by the specifying unit <NUM> on the display unit <NUM> so that it is recognizable that which work path P1 is specified as the automatic traveling candidate path P4 from multiple work paths P1. Since it will be recognizable with colors, for example, the terminal electronic control unit <NUM> makes the color of the automatic traveling candidate paths P4 on the display unit <NUM> different from that of the other work paths P1, so that the automatic traveling candidate paths P4 are recognizable.

The starting path specifying unit <NUM> specifies the starting path P5 from the automatic traveling candidate paths P4 specified by the specifying unit <NUM> (Step #<NUM> of <FIG>). If one automatic traveling candidate path P4 is specified by the specifying unit <NUM>, the starting path specifying unit <NUM> specifies the automatic traveling candidate path P4 as the starting path P5. As illustrated in <FIG>, if multiple automatic traveling candidate paths P4 are specified by the specifying unit <NUM>, the starting path specifying unit <NUM> specifies one starting path P5 (indicated by the thick line in <FIG>) from the multiple automatic traveling candidate paths P4, based on a starting path specification condition. For example, it is possible that the starting path specification condition is set as the automatic traveling candidate path P4 that is at the nearest position from the current position of the tractor <NUM>. For example, it is also possible the starting path specification condition is set as the automatic traveling candidate path P4 selected on the display unit <NUM> by a selection operation of the user or the like, so that the starting path P5 can be specified according to the demand from the user or the like.

It is possible for the terminal electronic control unit <NUM> to display the starting path P5 specified by the starting path specifying unit <NUM> on the display unit <NUM> so that, as illustrated with the thick line in <FIG>, which work path P1 is specified as the starting path P5 from multiple work paths P1 is recognizable. Since it will be recognizable with colors, for example, the terminal electronic control unit <NUM> makes the color of the automatic traveling candidate paths P4 on the display unit <NUM> different from that of the other work paths P1, so that the automatic traveling candidate paths P4 are recognizable.

Returning to Step #<NUM> of <FIG>, an explanation is given of the case in which the forward-reverse travel switching operation unit is switched to reverse traveling. In this case, the area selection unit <NUM> selects a state in which the candidate specification area Q2 is set on the rear side of the tractor <NUM>, and the candidate specification area setting unit <NUM> sets the rear-side candidate specification area Q2 on the rear side of the tractor <NUM> according to the state selected by the area selection unit <NUM> (Step #<NUM> in a case of REAR SIDE in Step #<NUM> of <FIG>). As illustrated in <FIG>, the candidate specification area setting unit <NUM> sets the right-side rear straight line T5 and left-side rear straight line T6 that are obtained by rotating the rear traveling straight line T4, which extends in the reverse traveling direction (rear-side straight traveling direction) of the tractor <NUM>, to the left and right by the rotation angle θ2 about the center, which is the current position of the tractor <NUM>. It is possible that θ2 is the same rotation angle as θ1 or is a different rotation angle. The area between the right-side rear straight line T5 and the left-side rear straight line T6 and in the range up to the set distance L from the current position of the tractor <NUM> is set as the rear-side candidate specification area Q2 by the candidate specification area setting unit <NUM>.

As with the front-side candidate specification area Q1, the rear-side candidate specification area Q2 is not limited to such a triangular-shaped area, and various shapes such as a quadrangular shape and an arc shape can be applied, for example. The candidate specification area setting unit <NUM> can also modify the setting of the size of the rear-side candidate specification area Q2 according to the situation of the tractor <NUM>, such as the current position of the tractor <NUM>.

The specifying unit <NUM> determines whether or not the orientation of the reverse traveling direction of the tractor <NUM> is laterally facing a work path P1 (Step #<NUM> of <FIG>). Here, although an illustration for the determination as to whether or not the orientation of the reverse traveling direction of the tractor <NUM> is laterally facing a work path P1 is omitted, the front and rear directions are opposite compared to <FIG>, and therefore, in a case where the angle formed by the right-side rear straight line T5 or the left-side rear straight line T6 (see <FIG>) and the straight line along a work path P1 is a predetermined angle, the specifying unit <NUM> determines that the tractor <NUM> is laterally facing a work path P1 with respect to the reverse traveling direction.

If the orientation of the reverse traveling direction of the tractor <NUM> is not laterally facing a work path P1, the specifying unit <NUM> determines whether or not a work path P1 exists inside the rear-side candidate specification area Q2, so as to specify a work path P1 existing inside the rear-side candidate specification area Q2 as an automatic traveling candidate path P4 (Step #<NUM> in a case of No in Step #<NUM> and Yes in Step #<NUM> of <FIG>). If one work path P1 exists inside the rear-side candidate specification area Q1, the specifying unit <NUM> specifies the one work path P1 as the automatic traveling candidate path P4. As illustrated in <FIG>, if multiple work paths P1 exist inside the rear-side candidate specification area Q2, the specifying unit <NUM> specifies the multiple work paths P1 (the four work paths P1, that is, the second to fifth work paths P1 from the left in <FIG>) as the automatic traveling candidate paths P4.

As in the case in which the front-side candidate specification area Q1 is set, the starting path specifying unit <NUM> specifies the starting path P5 from the automatic traveling candidate paths P4 specified by the specifying unit <NUM> (Step #<NUM> of <FIG>). If one automatic traveling candidate path P4 is specified by the specifying unit <NUM>, the starting path specifying unit <NUM> specifies the automatic traveling candidate path P4 as the starting path P5. If multiple automatic traveling candidate paths P4 are specified by the specifying unit <NUM>, the starting path specifying unit <NUM> specifies one starting path P5 (indicated by the thick line in <FIG>) from the multiple automatic traveling candidate paths P4, based on a starting path specification condition.

For displaying the starting paths P5 on the display unit <NUM>, as illustrated in <FIG>, the terminal electronic control unit <NUM> displays the starting path P5 included in the front-side candidate specification area Q1 (indicated by the thick dotted line) and the starting path P5 included in the rear-side candidate specification area Q2 (indicated by the thick line) in a distinguishable manner. Although they are distinguished with the solid thick line and the dotted thick line in <FIG>, since they are recognizable with colors, for example, it is possible for the display unit <NUM> to change the colors of the automatic traveling candidate paths P4 so as to be recognizable.

In this way, in the case where the front-side candidate specification area Q1 is set (see <FIG>) as well as in the case where the rear-side candidate specification area Q2 is set (see <FIG>), the specifying unit <NUM> specifies the automatic traveling candidate paths P4, so that the starting path specifying unit <NUM> specifies one starting path P5 from the automatic traveling candidate paths P4.

In <FIG>, when the front-side candidate specification area Q1 is set, in a case where there is no work path P1 existing inside the front-side candidate specification area Q1, or, when the rear-side candidate specification area Q2 is set, in a case where there is no work path P1 existing inside the rear-side candidate specification area Q2, Step #<NUM> to Step #<NUM> and Step #<NUM> are repeatedly performed. For example, in a case where the tractor <NUM> is moving, the front-side candidate specification area Q1 or the rear-side candidate specification area Q2 moves as well according to the movement (forward traveling or reverse traveling) of the tractor <NUM>. Therefore, automatic traveling candidate paths P4 can be specified if there is work paths P1 existing inside the front-side candidate specification area Q1 or rear-side candidate specification area Q2 after the movement. Note that it is also possible to suspend the specification of automatic traveling candidate paths P4 if a suspension condition is satisfied, such as when a predetermined time period elapses after the specification of automatic traveling candidate paths P4 is started.

When the starting path P5 is specified, the onboard electronic control unit <NUM> performs automatic travel control, in order to make the tractor <NUM> automatically travel so as to approach the starting path P5 and get on the starting path P5. For making the tractor <NUM> automatically travel so as to approach the starting path P5 and get on the starting path P5, the onboard electronic control unit <NUM> switches whether to travel forward or to travel backward according to whether the forward-reverse travel switching operation unit is switched to forward traveling or to reverse traveling (Step #<NUM> to Step #<NUM> of <FIG>). Note that, in practice, since the determination as to whether the forward-reverse travel switching operation unit is switched to forward traveling or to reverse traveling is made by the onboard electronic control unit <NUM> in Step #<NUM>, whether to travel forward or to travel backward on the starting path P5 is switched by use of the determination result of Step #<NUM>, instead of newly making a determination.

In a case where the forward-reverse travel switching operation unit is switched to forward traveling, the onboard electronic control unit <NUM> makes the tractor <NUM> automatically travel, so that the tractor <NUM> is made to travel forward to get on the starting path P5 (Step #<NUM> in a case of FRONT SIDE in Step #<NUM> of <FIG>).

After making the tractor <NUM> automatically travel to get on the starting path P5, the onboard electronic control unit <NUM> checks whether the automatic traveling starting condition is satisfied, and, in a case where the automatic traveling starting condition is satisfied, the onboard electronic control unit <NUM> makes the tractor <NUM> start the automatic traveling along the starting path P5 upon receiving an instruction for starting the automatic traveling (Step #<NUM> in a case of Yes in Step #<NUM> of <FIG>).

For example, the onboard electronic control unit <NUM> determines that the automatic traveling starting condition is satisfied if, out of the below-described (<NUM>) to (<NUM>), four conditions, that is, (<NUM>), (<NUM>), (<NUM>) or (<NUM>), and (<NUM>) are satisfied.

In a case where the forward-reverse travel switching operation unit is switched to reverse traveling, the onboard electronic control unit <NUM> makes the tractor <NUM> automatically travel, so that the tractor <NUM> is made to travel backward to get on the starting path P5 (Step #<NUM> in a case of REAR SIDE in Step #<NUM> of <FIG>).

In this case also, after making the tractor <NUM> automatically travel to get on the starting path P5, the onboard electronic control unit <NUM> checks whether the automatic traveling starting condition is satisfied, and, in a case where the automatic traveling starting condition is satisfied, the onboard electronic control unit <NUM> makes the tractor <NUM> start the automatic traveling along the starting path P5 upon receiving an instruction for starting the automatic traveling (Step #<NUM> in a case of Yes in Step #<NUM> of <FIG>). Note that, since the automatic traveling of the tractor <NUM> along the starting path P5 is performed by forward traveling, the tractor <NUM> is switched from reverse traveling to forward traveling on the starting path P5.

Since it is necessary for the onboard electronic control unit <NUM> to acquire path information related to the starting path P5 and the multiple work paths P1 in order to perform automatic traveling along the starting path P5 and the multiple work paths P1, an explanation is given of the acquisition of this path information.

Since it is possible for the terminal electronic control unit <NUM> to transmit the path information related to the starting path P5 by use of the communication module <NUM> at the stage where the starting path P5 is specified, the onboard electronic control unit <NUM> can acquire the path information related to the starting path P5 by receiving the path information by use of the communication module <NUM>. After the automatic traveling is started, the terminal electronic control unit <NUM> transmits path information related to work paths P1 by use of the communication module <NUM> each time the transmission timing comes. As a result, the onboard electronic control unit <NUM> acquires path information related to work paths P1 by receiving the path information by use of the communication module <NUM>. Therefore, the onboard electronic control unit <NUM> performs the automatic travel control based on the acquired path information related to the starting path P5 and work paths P1, so as to make the tractor <NUM> perform the automatic traveling along the starting path P5 and work paths P1.

This second embodiment is another embodiment of the configuration for the specifying unit <NUM> to specify automatic traveling candidate paths P4 in the above-described first embodiment. Hereinafter, the configuration for the specifying unit <NUM> to specify automatic traveling candidate paths P4 in the second embodiment will be explained, and the explanations of the other configurations are omitted.

Although the specifying unit <NUM> specifies work paths P1 included in the front-side candidate specification area Q1 or the rear-side candidate specification area Q2 as automatic traveling candidate paths P4 in the above-described first embodiment, the specifying unit <NUM> in this second embodiment does not specify a work path P1 corresponding to an exclusion condition as an automatic traveling candidate path P4 even though the work path P1 is included in the front-side candidate specification area Q1 or the rear-side candidate specification area Q2.

As for the exclusion condition, for example, it is possible to determine that a work path P1 corresponds to the exclusion condition if any of the conditions of below-described (<NUM>) to (<NUM>) are satisfied. Note that <FIG> shows a case in which the exclusion conditions defined in below-described (<NUM>) and (<NUM>) are met in a state where the front-side candidate specification area Q1 is set. In a state where the rear-side candidate specification area Q2 is set, since whether the front side or the rear side is the only difference, the illustration thereof is omitted.

The exclusion condition can be set as appropriate, and, for example, one condition or multiple conditions can be selected from above-described (<NUM>) to (<NUM>).

Explanations are given of other embodiments of the present invention. Note that the configuration of each embodiment explained below can be applied not only independently but also in combination with the configuration of another embodiment.

Here, as illustrated in <FIG>, since a predetermined travel direction is set for each of the multiple work paths P1, it is possible to specify a work path P1 whose travel direction is the same as the forward traveling direction of the tractor <NUM> as an automatic traveling candidate path P4. That is, when the front-side candidate specification area Q1 and the rear-side candidate specification area Q2 are set for specifying automatic traveling candidate paths P4, such a work path P1 that satisfies a condition of being a work path P1 whose travel direction is the same as the forward traveling direction of the tractor <NUM> in addition to a condition of being a work path P1 included in the front-side candidate specification area Q1 and the rear-side candidate specification area Q2 can be specified as an automatic traveling candidate path P4 by the specifying unit <NUM>.

(<NUM>) In the above-described embodiment, as illustrated in <FIG>, the starting path P5 included in the front-side candidate specification area Q1 (indicated by the thick dotted line) and the starting path P5 included in the rear-side candidate specification area Q2 (indicated by the thick line) are displayed on the display unit <NUM> in a distinguishable manner. Alternatively, it is also possible that the automatic traveling candidate paths P4 included in the front-side candidate specification area Q1 and the automatic traveling candidate paths P4 included in the rear-side candidate specification area Q2 are displayed on the display unit <NUM> in a distinguishable manner by the terminal electronic control unit <NUM>. Here, it is possible that the automatic traveling candidate paths P4 and the starting paths P5 are displayed in a distinguishable manner as well.

Claim 1:
An automatic travel system to make a work vehicle (<NUM>) automatically travel along a scheduled travel path, comprising:
a path generation unit (<NUM>) that generates the scheduled travel path including a plurality of travel paths (P1) ;
an automatic travel control unit (<NUM>) configured to make the work vehicle (<NUM>) to perform the automatic traveling along the scheduled travel path;
an information acquisition unit (<NUM>, <NUM>) configured to acquire position information and direction information of the work vehicle (<NUM>); and
a specifying unit (<NUM>) configured to specify an automatic traveling candidate path (P4), in order to allow the work vehicle (<NUM>) to start automatically traveling on it before the automatic traveling is started by the work vehicle (<NUM>),
wherein the specifying unit (<NUM>) is further configured to set candidate specification areas (Q1, Q2) on a front side and a rear side of the work vehicle (<NUM>), based on the position information and direction information of the work vehicle (<NUM>) acquired by the information acquisition unit (<NUM>, <NUM>), and to specify a travel path included in the candidate specification areas (Q1, Q2) as the automatic traveling candidate path out of the plurality of travel paths.