Farm working vehicle

Abstract

To provide a farm working vehicle capable of avoiding the situation where a machine body comes to an emergency stop due to the machine body crossing the border, during a turning travel in the automatic travel.SOLUTION: A farm working vehicle includes: a machine body position calculation part 52 for calculating a machine body position which is the position of the machine body on a field surface bounded by a boundary object; a crossing-border prevention control part 57b for prohibiting the travel of the machine body crossing the boundary based on a boundary set to avoid contact between the machine body and the boundary object and the machine body position; a turning locus estimation part 57c for estimating a turning locus which is the locus of the machine body during a turning travel; and a turning time crossing-border determination part 57d for determining whether or not the machine body crosses the border in the actual turning travel based on the estimated turning locus.SELECTED DRAWING: Figure 7

Description

Technical Field

[0001] The present invention relates to an automatically drivable agricultural work vehicle that travels on a field area bounded by boundary objects.

Background Art

[0002] The agricultural work vehicle according to Patent Document 1 includes a measuring device that detects the position of a traveling body using a satellite positioning system, an automatic driving control unit that automatically drives the traveling body along a set work traveling line, and an automatic deceleration unit that stops the traveling body when the traveling body approaches a ridge line that is a boundary line between a field area and a ridge.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In order for an agricultural work vehicle to travel over the entire field bounded by boundary objects such as ridges, it repeats forward travel toward the boundary object and turning travel (direction-changing travel) performed when approaching the boundary object. In the case of turning travel, depending on the turning start timing, the road surface condition of the field, the vehicle speed during turning, etc., the vehicle body may turn along a turning trajectory different from the assumed turning trajectory. When an automatically driven agricultural work vehicle as in Patent Document 1 turns near the boundary line, if the vehicle body turns closer to the boundary line than the assumed turning trajectory, the position of the vehicle body reaches the boundary line and the vehicle body makes an emergency stop. When the vehicle body makes an emergency stop during automatic driving, it is switched to manual driving, and it is necessary to perform turning travel so as not to cross the boundary line manually. Since such cross-border avoidance turning travel is time-consuming, the work is delayed.

[0005] Therefore, there is a demand for an agricultural work vehicle that can avoid, as much as possible, a situation in which the vehicle suddenly stops when it crosses a boundary line during turning driving in autonomous driving.

Means for Solving the Problem

[0006] The agricultural work vehicle according to the present invention can travel in a field area bounded by boundary objects in autonomous driving, and includes a vehicle body position calculation unit that calculates a vehicle body position, which is the position of the vehicle body in the field area, and a border crossing prevention control unit that prohibits the vehicle body from traveling beyond the boundary line based on a boundary line set to avoid contact between the vehicle body and the boundary object and the vehicle body position, a turning trajectory estimation unit that estimates a turning trajectory, which is a trajectory of the vehicle body during turning driving, and a turning border crossing determination unit that determines whether the vehicle body crosses the boundary line during actual turning driving based on the estimated turning trajectory.

[0007] According to this configuration, when the vehicle body performs turning driving, the turning trajectory during the turning driving is estimated in advance, and based on the estimated turning trajectory, it is determined whether the vehicle body crosses the boundary line during actual turning driving. The estimation of the turning trajectory by the turning trajectory estimation unit and the determination by the turning border crossing determination unit can be performed either before actual turning driving, during actual turning driving, or both. When a determination result indicating that the vehicle body will cross the boundary line is obtained, a recovery process is performed before the border crossing prevention control unit prohibits the vehicle body from traveling. This recovery process can be either manual or automatic. Such a recovery process not only has the advantage of being easier but also results in less time loss compared to performing it after the border crossing prevention control unit prohibits the vehicle body from traveling.

[0008] As the recovery process, before the vehicle body crosses the boundary line, the scheduled turning driving is canceled, and a border crossing avoidance turning driving is performed by moving to the turning driving start point or changing the turning radius. Therefore, in one preferred embodiment of the present invention, when the turning border crossing determination unit determines that the vehicle body crosses the boundary line, a border crossing avoidance turning driving is performed.

[0009] An example of the cross-border avoidance turning travel is that if the steering angle of the planned turning travel is less than the maximum steering angle, the turning trajectory in the turning travel using the maximum steering angle is estimated. If the result of the cross-border determination during turning based on the estimated turning trajectory is good, the crossing of the boundary line can be avoided by the turning travel at the maximum steering angle. Therefore, in one of the preferred embodiments of the present invention, the cross-border avoidance turning travel includes the turning travel at the maximum steering angle. To more surely avoid crossing the boundary line, generally, a direction-changing travel (a kind of turning travel) using reverse travel, which is called a reversing travel, is suitable. From this, in one of the preferred embodiments of the present invention, the cross-border avoidance turning travel includes reverse travel.

[0010] In many farm operations in the field by a farm work vehicle, the field surface to be worked is divided into an outer peripheral region and an inner region located inside this outer peripheral region. The work in the inner region is performed by repeating straight-ahead travel for working and turning travel (mainly U-turn travel) for which no work is performed for direction change. From this, it is not uncommon for the vehicle body to be controlled to temporarily stop before shifting from straight-ahead travel in the inner region to turning travel in the outer peripheral region. To utilize such control, in one of the preferred embodiments of the present invention, the field surface is divided into an outer peripheral region along the boundary line and an inner region located inside the outer peripheral region. The automatic travel work in the inner region is performed by repeating straight-ahead travel in the inner region and the turning travel in the outer peripheral region. When shifting from the straight-ahead travel to the turning travel, the vehicle body is temporarily stopped. During the temporary stop, the turning trajectory is estimated and the cross-border determination during turning is performed. Thereby, the temporary stop of the vehicle body that occurs when shifting from straight-ahead travel to turning travel can be effectively utilized. Note that the term "straight-ahead travel" used in the present invention does not only mean straight-line travel but also includes curved travel with a large radius of curvature.

[0011] Even if it is determined that there is no border crossing of the aircraft by estimating the travel trajectory of the turning travel before the turning travel, there is a possibility that the aircraft may cross the border due to slipping or the like during the turning travel. To avoid this, even during the turning travel, a border crossing determination based on the turning trajectory estimated at that time is performed. If it is determined that a border crossing has occurred, it is necessary to temporarily stop the aircraft and switch to a new turning travel that avoids the border crossing. Therefore, in one of the preferred embodiments of the present invention, when it is determined by the turning border crossing determination unit that the aircraft has crossed the boundary line during the turning travel, the aircraft is stopped and a new avoidance turning is searched for.

[0012] Since control is performed to avoid interference with the boundary object based on the boundary line and the aircraft position, it is preferable that the boundary line calculation and the aircraft position are calculated in the same manner. Therefore, in one of the preferred embodiments of the present invention, the aircraft position calculation unit calculates the aircraft position using satellite positioning, and the position of the boundary line is calculated based on the aircraft position (travel trajectory) during the circular travel along the outermost periphery of the field scene.

Brief Description of the Drawings

[0013]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Embodiments for Carrying Out the Invention

[0014] As an embodiment of the agricultural work vehicle according to the present invention, a riding type rice transplanter will be taken up and described below. This rice transplanter can automatically travel in a field area bounded by boundary objects. In this specification, unless otherwise specified, "front" means the front in the longitudinal direction (travel direction) of the machine body, and "rear" means the rear in the longitudinal direction (travel direction) of the machine body. Also, the left-right direction or the lateral direction means the transverse direction (machine body width direction) of the machine body orthogonal to the longitudinal direction of the machine body. "Up" or "down" is the positional relationship in the vertical direction (perpendicular direction) of the machine body, indicating the relationship at the ground height.

[0015] FIG. 1 is a side view of the rice transplanter. The rice transplanter includes a riding type four-wheel drive traveling machine body (hereinafter referred to as the machine body 1). The machine body 1 includes a link mechanism 11 of a parallel four-link type that is connected to the rear part of the machine body 1 so as to be able to swing up and down, a hydraulic lifting cylinder 11a that swing-drives the link mechanism 11, a seedling planting device 3 (an example of an agricultural material applying device) that is connected to the rear end part of the link mechanism 11 so as to be able to roll, and a fertilizer applying device 4 that is installed from the rear end part of the machine body 1 to the seedling planting device 3.

[0016] The machine body 1 includes wheels 12, an engine 13, and a hydraulic continuously variable transmission 14 as mechanisms for traveling. The wheels 12 include left and right front wheels 12A that can be steered and left and right rear wheels 12B that cannot be steered. The engine 13 and the continuously variable transmission 14 are mounted on the front part of the machine body 1. The power from the engine 13 is supplied to the front wheels 12A, the rear wheels 12B, etc. via the continuously variable transmission 14 and the like.

[0017] The seedling planting device 3 is configured in an 8-row planting type as an example. The seedling planting device 3 includes a seedling placing table 31, planting mechanisms 32 for 8 rows, etc. Note that this seedling planting device 3 can be changed to a form such as 2-row planting, 4-row planting, 6-row planting, etc. by controlling each row clutch (not shown).

[0018] The seedling placing table 31 is a pedestal for placing mat-shaped seedlings for eight rows. The seedling placing table 31 reciprocates in the left-right direction with a constant stroke corresponding to the left-right width of the mat-shaped seedlings. Each time the seedling placing table 31 reaches the left and right stroke ends, the vertical feeding mechanism 33 vertically feeds each mat-shaped seedling on the seedling placing table 31 toward the lower end of the seedling placing table 31 at a predetermined pitch. The eight planting mechanisms 32 are rotary type and are arranged in the left-right direction at a constant interval corresponding to the row spacing of planting. And each planting mechanism 32 cuts out a seedling for one plant from the lower end of each mat-shaped seedling placed on the seedling placing table 31 by the power from the machine body 1 and plants it in the soil part after land preparation.

[0019] The seedling planting device 3 is provided with a seedling taking amount adjusting function for adjusting the seedling taking amount by the planting mechanism 32. The planting mechanism 32 takes out and plants a seedling for one plant through the seedling taking outlet formed in the guide rail that slidably guides the lower end of the seedling placing table 31. The seedling taking amount is adjusted by changing the vertical positions of the seedling placing table 31 and the guide rail that slidably guides the lower end of the seedling placing table 31.

[0020] As shown in FIG. 1, the fertilizer application device 4 includes a horizontally long hopper 41, a feeding mechanism 42, an electric blower 43, a plurality of fertilizer hoses 44, and a furrow opener 45 provided for each row. The hopper 41 stores granular or powdered fertilizer. The feeding mechanism 42 is operated by the power transmitted from the engine 13 and feeds out the fertilizer for two rows from the hopper 41 in predetermined amounts. This fertilizer application device 4 has a feeding amount adjusting function for changing the feeding amount of the fertilizer by the feeding mechanism 42.

[0021] The blower 43 is operated by the power from a battery (not shown) mounted on the machine body 1 and generates a conveying wind for conveying the fertilizer fed out by each feeding mechanism 42 toward the mud surface of the field. The fertilizer application device 4 can be switched between an operating state in which the fertilizer stored in the hopper 41 is supplied to the field in predetermined amounts by intermittent operation of the blower 43 and the like and a non-operating state in which the supply is stopped.

[0022] Each fertilizer hose 44 guides the fertilizer conveyed by the conveying air to each furrow opener 45. Each furrow opener 45 is provided on each leveling float 15. And each furrow opener 45 moves up and down together with each leveling float 15, and when the machine is traveling in the field with each leveling float 15 in contact with the ground, a fertilization groove is formed in the muddy part of the paddy field to guide the fertilizer into the fertilization groove.

[0023] The machine body 1 is provided with an operation unit 20 on its rear side. The operation unit 20 is equipped with, as manual traveling operation tools, a steering wheel 21 for front wheel steering, a main shift lever 22 for adjusting the vehicle speed by performing a shift operation of the continuously variable transmission 14, a sub-shift lever 23 enabling a shift operation of the sub-transmission, a work operation lever 25 enabling operations such as raising and lowering of the seedling planting device 3 and switching of the operating state, etc. Further, a general-purpose terminal 9 is provided in front of the driver's seat 16. The general-purpose terminal 9 is equipped with a notification device for displaying various information and notifying the operator and a touch panel for receiving input of various information. A driving mode switching operation tool 24 by the driver is provided around the steering wheel 21. Further, a spare seedling frame 17 for accommodating spare seedlings is provided in front of the operation unit 20.

[0024] The steering wheel 21 is connected to the front wheels 12A via a steering mechanism (not shown), and the steering angle of the front wheels 12A is adjusted through the rotation operation of the steering wheel 21. A steering motor M1 is also connected to the steering mechanism, and during automatic traveling, the steering angle of the front wheels 12A is adjusted by the operation of the steering motor M1 based on a steering signal. Further, a shift operation motor M2 for automatically operating the main shift lever 22 is also provided, and during automatic traveling, the shift position of the continuously variable transmission 14 is adjusted by the operation of the shift operation motor M2 based on a shift signal.

[0025] On the upper part of the preliminary seedling frame 17, an extension frame 17a extending upward is provided. On this extension frame 17a, a stacked lamp 18 with a plurality of color lamps arranged vertically for notifying the outside of the state of the rice transplanter and a positioning unit 8 are attached. The positioning unit 8 outputs positioning data for calculating the position and orientation (aircraft orientation) of the aircraft 1. The positioning unit 8 includes a satellite positioning module 8A that receives radio waves from satellites of the global navigation satellite system (GNSS) and an inertial measurement module 8B that detects the inclination and acceleration of the three axes of the aircraft 1.

[0026] An example of the processing procedure in the seedling planting operation combining the automatic running and the manual running by this rice transplanter is shown in FIG. 2. In the example of FIG. 2, this seedling planting operation includes pre-operation processing #A, map creation processing #B, boundary line calculation processing #C, route generation processing #D, work start point guidance processing #E, inner reciprocating planting processing #F, and outer peripheral planting processing #H.

[0027] In the pre-operation processing #A, communication checks between each unit of the control system of the rice transplanter and communication checks of the positioning unit 8 are performed. Further, in the rice transplanter, remote control using a remote controller 90 (see FIG. 1) and obstacle detection by an obstacle detector 80 (see FIG. 3) are performed, so function checks of the remote controller 90 and the obstacle detector 80 are also performed as pre-processing. As shown in FIG. 3, the obstacle detector 80 in this embodiment is of a sonar type and includes four front sonars 80f with the front of the aircraft 1 as the detection range, two side sonars 80s with the left and right of the aircraft 1 as the detection range, and two rear sonars 80r with the front of the aircraft 1 as the detection range.

[0028] The map creation processing #B is a process of measuring the map of the field to be worked, that is, the outer shape of the field surface. The running trajectory is calculated based on the position signal from the positioning unit 8 obtained when the rice transplanter manually runs (map creation teaching running) along the boundary objects such as the ridges bounding the field surface, that is, along the outermost periphery of the field surface. From this running trajectory, a field contour line as map information of the field surface, that is, a field map, is obtained.

[0029] In the boundary line calculation process #C, as shown in FIG. 4, a boundary line indicating the position of the machine body 1 that is the limit for the rice transplanter to avoid contact with the boundary objects in the field is calculated from the travel trajectory calculated in the map creation process #B. During the normal travel of the rice transplanter, as long as the position of the machine body 1 does not cross this boundary line (also called the border line), the rice transplanter does not come into contact with boundary objects such as ridges. When the position of the machine body 1 reaches the boundary line, the machine body 1 is forcibly stopped. Since this rice transplanter can perform automatic driving, a safety distance is added so that the rice transplanter does not come into contact with boundary objects such as ridges even if unexpected slips or steering fluctuations occur, and the position of the final boundary line is determined.

[0030] In the route generation process #D, a travel route that is the target of automatic driving set in the field map created in the map creation process #B is created by a predetermined algorithm. The travel route generated for the seedling planting operation in automatic driving will be described below.

[0031] As shown in FIG. 4, the field area defined by the field map is divided into an outer peripheral area and an inner area. The generated travel route consists of a circular travel route set in the outer peripheral area (see FIG. 5) and a reciprocating travel route set in the inner area (see FIG. 6). The rice transplanter first performs a seedling planting operation (a type of automatic driving operation) on the inner area along the reciprocating travel route (referred to as the inner operation travel mode), and then performs a seedling planting operation on the outer peripheral area along the circular travel route (referred to as the circular operation travel mode).

[0032] The circular travel path consists of a circular straight path extending parallel to the field boundary (ridge) and a direction-changing path incorporating forward and backward movements to connect the circular straight paths. In FIG. 5, the circular straight path is assigned the reference symbol R1, and the direction-changing path is assigned the reference symbol R2. The reciprocating travel path consists of a number of substantially parallel straight travel paths and a turning path (U-turn path) connecting the straight travel paths. In each straight travel path, the planting of seedlings is started from the planting start position (which is also the turning end position), and the planting of seedlings is completed at the planting end position (which is also the turning start position). In FIG. 6, the reference symbol US is assigned to the planting start position, the reference symbol UF is assigned to the planting end position, the reference symbol R3 is assigned to the straight travel path, and the reference symbol R5 is assigned to the turning path. In FIGS. 5 and 6, the reference symbol R4 is assigned to the transition path for transitioning from the reciprocating travel path to the circular travel path. In the example here, the transition path is similar to the turning path. Further, in FIGS. 5 and 6, the working width of the rice transplanter is indicated by the reference symbol W, the entrances and exits of the rice transplanter to the field are drawn in oblique lines and assigned the reference symbol GA. In FIG. 6, the start guiding path (assigned the reference symbol R6 in FIG. 6) from the entrance and exit to the travel start position (assigned the reference symbol S in FIG. 6) of the reciprocating travel path is shown. In the turning path, the direction-changing path, the start guiding path, and the transition path, the rice transplanter travels without performing work, so these paths are indicated by dotted lines. In the circular straight path and the straight travel path, the rice transplanter travels while performing work, so these paths are indicated by solid lines.

[0033] In the operation start point guiding process #E, first, the rice transplanter manually travels, enters the field through the entrance and exit, and stops at a predetermined position. Thereafter, along the start guiding path, which is the travel path to the travel start position that is the start point of the seedling planting operation, the rice transplanter automatically travels to the travel start position.

[0034] In the inner reciprocating planting process #F, the travel mode becomes the internal operation travel mode, and it automatically travels along the reciprocating travel path shown in FIG. 6, and the seedling planting operation in the internal area is performed. When seedling replenishment is necessary, the seedling replenishment process #G is performed.

[0035] When the inner reciprocating planting process #F is completed, the traveling mode becomes the circular work traveling mode, and the outer planting process #H, which is a seedling planting operation along the circular traveling route shown in FIG. 5, is executed. In this embodiment, the circular traveling route consists of an inner circular traveling route for one round of the first traveling and an outer circular traveling route for one round of the subsequent traveling. Basically, since the end position of the outer circular traveling route is the entrance / exit of the field, after the seedling planting operation along the outer circular traveling route, the rice transplanter exits the field through the entrance / exit. The seedling planting operation along the inner circular traveling route is performed by automatic driving. Since the seedling planting operation along the outer circular traveling route requires precise traveling, even in the case of automatic driving, manned automatic driving with the driver as a monitor on board is preferred.

[0036] FIG. 7 shows a control block diagram of the control system of this rice transplanter. The control system of the rice transplanter includes a control device 100 that controls various operations of the rice transplanter, a general-purpose terminal 9 and a remote controller 90 that can exchange data with the control device 100. Signals from a positioning unit 8, a driving mode switching operation tool 24, a traveling sensor group 28, a work sensor group 29, and an obstacle detector 80 are input to the control device 100. Control signals from the control device 100 are output to a traveling device group 1A and a work device group 1B.

[0037] The traveling device group 1A includes, for example, a steering motor M1 and a shift operation motor M2. Based on the control signal from the control device 100, the steering angle is adjusted by controlling the steering motor M1, and the vehicle speed is adjusted by controlling the shift operation motor M2.

[0038] The work device group 1B includes, for example, a lifting cylinder 11a that adjusts the lifting of the seedling planting device 3, a seedling taking amount adjusting device that adjusts the seedling taking amount by the planting mechanism 32, a feeding amount adjusting device that changes the feeding amount of fertilizer by the feeding mechanism 42, and the like.

[0039] The traveling sensor group 28 includes various sensors that detect states such as the steering angle, vehicle speed, engine speed, etc. and set values for them. The working sensor group 29 includes various sensors that detect the states of the link mechanism 11, the seedling planting device 3, and the fertilizer application device 4.

[0040] The control device 100 is provided with a traveling control unit 6, a working control unit 51, a machine body position calculation unit 52, a traveling route management unit 53, a driving control state detection unit 55, a border crossing management unit 57, an input signal processing unit 50a, and a communication unit 50b.

[0041] The input signal processing unit 50a processes signals from various sensors, switches, levers, etc. provided in the rice transplanter and transfers them to the functional units constructed in the control device 100. The communication unit 50b has a wireless communication function, performs data communication with the outside, for example, data communication with the remote controller 90, and the received data is transferred to the input signal processing unit 50a.

[0042] The traveling control unit 6 is provided with an automatic traveling control unit 6A, a manual traveling control unit 6B, and a control management unit 6C. The automatic traveling control unit 6A performs speed control and steering control during automatic traveling. Based on the lateral deviation and the azimuth deviation calculated by comparing the target traveling route set by the traveling route management unit 53 and the machine body position calculated by the machine body position calculation unit 52, steering control is performed so that the lateral deviation and the azimuth deviation are reduced.

[0043] In this rice transplanter, in addition to the automatic traveling mode in which it automatically travels along the target traveling route, there is provided a straight-line maintenance driving mode in which it automatically travels straight ahead so as to maintain the azimuth of the reference line defined by at least two points. As the reference line used in the straight-line maintenance driving mode, the straight traveling route managed by the traveling route management unit 53 can be diverted.

[0044] In the manual driving mode, the manual driving control unit 6B controls the steering motor M1 based on the operation amount of the steering wheel 21. The control management unit 6C selects one of the automatic driving mode, the straight-line maintenance driving mode, and the manual driving mode based on the signal from the driving mode switching operation tool 24.

[0045] In automatic driving, the work control unit 51 automatically controls the work equipment group 1B based on a previously given program, and in manual driving, it controls the work equipment group 1B based on the driver's operation. The aircraft position calculation unit 52 calculates the map coordinates (aircraft position) of the aircraft 1 based on the satellite positioning data sequentially sent from the positioning unit 8.

[0046] In this embodiment, the general-purpose terminal 9 is provided with a field information storage unit 91, a field map creation unit 92, a travel route generation unit 93, a boundary line calculation unit 94, and a travel trajectory generation unit 95. The field information storage unit 91 stores information related to the field, such as the crop type to be planted, the position of the field entrance (exit), and the seedling replenishment possible position. The field map creation unit 92 performs the map creation process described with reference to FIG. 2. The travel route generation unit 93 divides the field into an outer peripheral area and an internal area based on the field map created by the field map creation unit 92, and generates a circular travel route for traveling in the outer peripheral area and a reciprocating travel route for the internal area. The boundary line calculation unit 94 performs the boundary line calculation process described with reference to FIG. 2. The map creation process by the field map creation unit 92 and the boundary line calculation process by the boundary line calculation unit 94 require the travel trajectory in the map creation teaching travel. The travel trajectory generation unit 95 generates the travel trajectory of the aircraft 1 based on the aircraft position calculated by the aircraft position calculation unit 52.

[0047] The travel route management unit 53 receives and manages the travel route generated by the travel route generation unit 93 from the general-purpose terminal 9, and sequentially sets the travel route that is the target of aircraft steering in the automatic driving mode.

[0048] The driving control state detection unit 55 detects the travel control state and the work control state based on the control information handled by the control device 100.

[0049] The border crossing management unit 57 has a function to avoid the aircraft 1 from contacting a boundary object such as a ridge when the aircraft 1 crosses the boundary line (boundary line data) calculated by the boundary line calculation unit 94. For this purpose, the border crossing management unit 57 includes a boundary line storage unit 57a, a border crossing prevention control unit 57b, a turning trajectory estimation unit 57c, and a turning border crossing determination unit 57d.

[0050] The boundary line storage unit 57a stores the boundary line received from the boundary line calculation unit 94. The border crossing prevention control unit 57b determines whether the aircraft 1 crosses the boundary line based on the aircraft position, and gives a stop command that prohibits the aircraft 1 from traveling beyond the boundary line to the travel control unit 6. The border crossing prevention control unit 57b has a straight - ahead border crossing prevention mode for preventing border crossing of the straight - ahead traveling aircraft 1 and a turning border crossing prevention mode for preventing border crossing of the turning traveling aircraft 1.

[0051] In the straight - ahead border crossing prevention mode, the border crossing prevention control unit 57b calculates the separation distance between the aircraft 1 and the boundary line from the aircraft position given by the aircraft position calculation unit 52 and the boundary line facing the aircraft traveling direction read from the boundary line storage unit 57a. When the calculated separation distance is within a predetermined distance, the border crossing prevention control unit 57b gives a stop command to the travel control unit 6.

[0052] During turning travel, since the rear end or the front end of the aircraft 1 sways laterally, border crossing prevention control based on the calculation of the separation distance like in the straight - ahead border crossing prevention mode is not used, and border crossing prevention control by the turning border crossing prevention mode is performed. In this turning border crossing prevention mode, border crossing prevention control based on the estimated turning trajectory of the aircraft 1 is performed using the turning trajectory estimation unit 57c and the turning border crossing determination unit 57d. The turning trajectory estimation unit 57c estimates the turning trajectory which is the trajectory of the aircraft 1 during turning travel. The turning border crossing determination unit 57d determines whether the aircraft actually crosses the boundary line in the actual turning travel based on the estimated turning trajectory.

[0053] Next, using the flowchart of FIG. 8, the control routine for preventing border crossing (border crossing prevention routine) by the border control unit 57 will be described. In this routine, first, it is checked whether the start of turning is approaching from the set travel route for automatic driving (#01). If the start of turning is not approaching, step #01 is repeated. If it is just before the start of turning (#01 Yes branch), it is further checked whether at least a part of the aircraft 1 has entered a preset border crossing prevention area (in this embodiment, the area between the border crossing prevention line set on the inner area side of the border line and boundary objects such as ridges, or the above-described outer peripheral area may also be used) (#02). If the aircraft 1 is outside the border crossing prevention area (#02 "outside" branch), the process returns to step #01. If the aircraft 1 is inside the border crossing prevention area (#02 "inside" branch), the following pre-turn border crossing determination process is performed.

[0054] In the pre-turn border crossing determination process, based on the aircraft position and the steering angle used for turning, the turning trajectory during turning is estimated by the turning trajectory estimation unit 57c (#11). Next, the turning border crossing determination unit 57d determines whether the aircraft 1 will cross the boundary line in the actual turning to be performed based on the estimated turning trajectory (#12). If the result of this border crossing determination is "non-border crossing" (#12 "non-border crossing" branch), the current turning is permitted (#21), and the turning is started (#22).

[0055] If the result of the border crossing determination is "border crossing" (#12 "border crossing" branch), the border crossing prevention control unit 57b sets a first border crossing avoidance turning travel to avoid border crossing (#13), and the turning trajectory in this set border crossing avoidance turning travel is estimated by the turning trajectory estimation unit 57c (#14). Based on the estimated turning trajectory, it is determined whether the aircraft 1 crosses the border line during this border crossing avoidance turning travel (#12). If the result of this border crossing determination is "non-border crossing" (#12 "non-border crossing" branch), the border crossing avoidance turning travel is permitted (#21), and the turning travel is started (#22). If the result of the border crossing determination is "border crossing" (#12 "border crossing" branch), it returns to step #13, and a second border crossing avoidance turning travel is set. The border crossing avoidance travel using reverse (so-called turning around travel) ensures border crossing avoidance but causes time loss. The border crossing avoidance travel using only forward (turning travel using the maximum steering angle or the speed difference between the left and right wheels) does not ensure border crossing avoidance but has less time loss. Therefore, the first border crossing avoidance turning travel uses the border crossing avoidance travel using only forward, and the second border crossing avoidance turning travel uses the border crossing avoidance travel using reverse.

[0056] When the turning travel is started, it is checked based on the information from the operation control state detection unit 55 whether the turning travel has ended (#23). When the turning travel ends (#23 Yes branch), it returns to step #01, and this border crossing prevention routine is repeated. If it is during the turning travel (#23 No branch), the following in-turning border crossing determination process is performed.

[0057] In the cross-border determination process during turning, first, an actual cross-border determination is performed to determine whether at least a part of the aircraft 1 has crossed the border at the current position (#31). If the result of the actual cross-border determination is "not crossed the border" (#31 "not crossed the border" branch), the process returns to step #23 and the turning travel continues. If the result of the actual cross-border determination is "crossed the border" (#12 "crossed the border" branch), the cross-border prevention control unit 57b gives a stop command to the travel control unit 6, and the aircraft 1 stops (#33). Next, the cross-border prevention control unit 57b sets a cross-border avoidance turning travel to depart from the border line using reverse travel (#34), and the turning trajectory in this set cross-border avoidance turning travel is estimated by the turning trajectory estimation unit 57c (#35). Based on the estimated turning trajectory, it is determined whether the aircraft 1 crosses the border line in this cross-border avoidance turning travel (#36). If the result of this cross-border determination is "not crossed the border" (#36 "not crossed the border" branch), this cross-border avoidance turning travel is permitted, the turning travel resumes (#37), and the control returns to step #23.

[0058] If the result of the cross-border determination is "crossed the border" (#12 "crossed the border" branch), a warning that the aircraft 1 cannot depart from the border line in automatic driving is notified through the general-purpose terminal 9 (#41). At the same time, the automatic driving is canceled (#42), and this cross-border prevention routine ends. After that, the cross-border prevention control is turned off, and in manual driving, the aircraft 1 is carefully detached outside the border line while avoiding interference between the aircraft 1 and the border object.

[0059] In step #02, if the state of the aircraft 1 is immediately before the start of turning and the aircraft 1 has entered the cross-border prevention area, the aircraft 1 may be temporarily stopped once and then proceed to the next step.

[0060] 〔Alternative Embodiment〕 (1) In the above embodiment, in steps #13, #14, and #15, as the cross-border avoidance turning travel, the first cross-border avoidance turning travel only forward and the second cross-border avoidance turning travel using reverse travel were applied in order, but only the second cross-border avoidance turning travel may be used. (2) In the above embodiment, the field map creation unit 92, the travel route generation unit 93, the boundary line calculation unit 94, and the travel trajectory generation unit 95 were constructed in the general-purpose terminal 9. However, at least a part of them may be constructed in the control device 100. Furthermore, it may be constructed in an external management computer capable of exchanging data with the control device 100. (3) The steering angle on the turning route by the automatic driving control unit 6A may be controlled to follow the generated turning route, or may be controlled using a steering angle determined in advance so as to form a predetermined turning route. (4) In the above embodiment, a rice transplanter was adopted as the agricultural work vehicle. However, an agricultural work vehicle such as a combine harvester, a tractor, a direct seeder, or a spray (dispersion) management machine may also be used.

[0061] Note that the configurations disclosed in the above embodiments (including other embodiments, the same applies hereinafter) can be applied in combination with the configurations disclosed in other embodiments as long as there is no contradiction. Also, the embodiments disclosed in this specification are examples, and the embodiments of the present invention are not limited to these, and can be appropriately modified within the scope not departing from the object of the present invention.

Industrial Applicability

[0062] The present invention is applicable to an agricultural work vehicle capable of automatic driving.

Explanation of Signs

[0063] 1: Vehicle body 6: Travel control unit 8: Positioning unit 8A: Satellite positioning module 8B: Inertial measurement module 9: General-purpose terminal 52: Vehicle body position calculation unit 53: Travel route management unit 55: Driving control state detection unit 57: Border crossing management unit 57a: Boundary line storage unit 57b: Border crossing prevention control unit 57c: Turning trajectory estimation unit 57d: Crossing determination unit during turning 94: Boundary line calculation unit 95: Travel trajectory generation unit 100: Control device

Claims

【Claim 1】 An agricultural work vehicle capable of autonomous driving that travels in a field area bounded by boundary objects, a vehicle position calculation unit that calculates a vehicle position, which is the position of the vehicle body in the field area, a border crossing prevention control unit that prohibits the vehicle from traveling beyond the boundary line based on the boundary line set to avoid contact between the vehicle body and the boundary object and the vehicle position, a turning trajectory estimation unit that estimates a turning trajectory, which is the trajectory of the vehicle during turning, and a turning border crossing determination unit that determines whether the vehicle body crosses the boundary line during actual turning based on the estimated turning trajectory. An agricultural work vehicle comprising the above components.

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