WO2023112611A1

WO2023112611A1 - Automatic steering system

Info

Publication number: WO2023112611A1
Application number: PCT/JP2022/042997
Authority: WO
Inventors: 大久保樹; 久保田祐樹
Original assignee: 株式会社クボタ
Priority date: 2021-12-17
Filing date: 2022-11-21
Publication date: 2023-06-22
Also published as: JP2023090397A

Abstract

The present invention is an automatic steering system for an autonomous travel work vehicle transitioning from a previous travel path Lf to a subsequent travel path Ln via turning travel. The automatic steering system comprises: a starting steering control unit which sets a starting steering angle as a turning steering angle for starting turning travel during turning travel; and an ending steering control unit which sets an ending steering angle as a turning steering angle for ending turning travel carried out after the starting turning travel at the starting steering angle has finished and the distance from a vehicle body 1 to the subsequent travel path Ln has reached a prescribed approach distance D1, or the distance from the previous travel path Lf to the vehicle body 1 has reached a prescribed separation distance D2.

Description

automatic steering system

The present invention relates to an automatic steering system for an automatic traveling work vehicle that transitions from a previous traveling route to a next traveling route through turning.

The self-driving work vehicle automatically travels using its own vehicle position calculated using satellite positioning, etc., and the travel route set in the work area. For example, an automatic traveling vehicle that is put into a field or the like travels along parallel linear travel paths connected by U-turn travel for field work. At that time, the optimal automatic steering for U-turn traveling, which transitions from a straight preceding travel route to the next travel route, requires turning speed (time required for turning), turning occupied space (space required for turning), and turning accuracy ( Accuracy of reaching the next travel route) and smooth turning trajectory (do not disturb the work area) must be considered.

In the automatic steering system according to Patent Document 1, the first turning travel (start turning travel) for leaving the preceding travel route is performed at a preset steering angle, and the second turning travel (starting travel travel) for entering the next travel route is performed. The final turning travel) is performed along the preset final turning circle, and the intermediate travel between the first turning travel and the second turning travel is along the tangent line drawn from the vehicle body to the final turning circle. done.

In the automatic steering system according to Patent Document 2, a preset starting turning path for leaving the previous traveling path and a preset final turning path for entering the next traveling path are used. The turning radius is larger than the turning radius of the final turning path.

JP 2018-185671 A JP 2020-031593 A

In the turning travel in Patent Documents 1 and 2, if the starting end of the final turning path to be guided to the next travel path is not accurately reached, hunting occurs in the steering control along the final turning path, and the next travel path is smoothly performed. The problem arises that it is not reached. When traveling on the final turning path ends in an overshoot state in turning control, the vehicle body slips beyond the next traveling path, and when traveling on the final turning path ends in an undershooting state, the vehicle body shifts to the next traveling path. It slips to the front side. Also, if hunting occurs during turning control, the field will be greatly damaged.

An object of the present invention is to provide an automatic steering system that improves the accuracy of entering the next travel route when leaving the previous travel route and entering the next travel route.

According to the present invention, there is provided an automatic steering system for an automatically traveling working vehicle that transitions from a previous traveling route to a next traveling route through turning traveling, wherein a starting steering degree is set as a turning steering degree for starting turning traveling in the turning traveling. a steering control unit, when the distance from the vehicle body to the next travel route reaches a predetermined approach distance after the end of the start turning travel by the start steering degree, or when the distance from the previous travel route to the vehicle body reaches a predetermined distance; and a final steering control unit for setting a final steering degree as the turning steering degree of the final turning traveling performed when the leaving distance is reached. The steering degree means the steering angle when the steering mechanism is a steerable wheel, and means the speed difference between the left and right crawlers when the steering mechanism is a crawler. Of course, the steering degree may be the turning radius.

According to this configuration, the turning travel for transitioning from the previous travel route to the next travel route consists of the starting turning travel, which is the first turning travel, and the final turning travel, which is the turning travel for entering the next travel route. Become. The start of the final turning travel is based on the distance from the vehicle body to the next travel path or the distance from the previous travel path to the vehicle body. The final steering degree used in this final turning travel can be calculated in advance based on the distance from the vehicle body to the next travel route. High-precision steering control, such as setting the final turning start point as a target point, is unnecessary for traveling from the end of the initial turning travel to the start of the final turning travel. When the positional relationship between the vehicle body and the next travel route reaches a predetermined relationship, the vehicle body is steered toward the next travel route. For example, when the positional relationship between the vehicle body and the next travel route becomes a predetermined relationship, if the vehicle body is steered toward the next travel route at a predetermined steering angle, a complicated turning control algorithm is unnecessary. Become. That is, the work vehicle always starts the final turning travel in a positional relationship set in advance with respect to the next travel route, so that the approach accuracy to the next travel route is stabilized. When the work vehicle is a rice transplanter, the stable entry into the next travel route guarantees an accurate seedling planting position, resulting in an increase in yield.

In one embodiment for preferably applying the present invention, the previous travel route and the next travel route are target travel routes extending parallel to each other, the turning travel is a 180-degree turning travel, and the start The steering control unit shifts the steering angle from the starting steering angle to a neutral steering angle before or after the change in direction of the vehicle body in the starting turning travel reaches 90 degrees.

The work travel route pattern frequently used by self-driving work vehicles, especially work vehicles that perform field work, is a pattern in which multiple straight-line travel routes are connected in a 180-degree turn. A 180 degree turning run consists of two 90 degree turning runs. In this configuration, when the distance between the previous travel route and the next travel route is long, the steering angle begins to return to the neutral steering angle when the azimuth change of the vehicle body reaches approximately 90 degrees, preferably close to 90 degrees, at the start of turning. It runs straight until it is time to start turning. Of course, well before the heading change reaches 90 degrees, the steering degree may gradually begin to return to the neutral steering degree. The interval between the previous travel route and the next travel route is short, and when the start timing of the final turning travel comes before the azimuth change of the vehicle reaches 90 degrees in the starting turning travel, the final turning travel is started at that point. In either case, since the final turning travel is started with the positional relationship set in advance with respect to the next travel route, the accuracy of entering the next travel route is stabilized.

In one preferred embodiment of the present invention, the predetermined approach distance or the predetermined departure distance is such that the bearing of the vehicle body coincides with the extension direction line of the next travel route due to the final turning travel using the final steering degree. is set to

As an ideal case, even if the vehicle body has not reached the starting point of the next travel route at the end of the final turn, if the vehicle body is aligned with the extension line of the next travel route, it will continue straight ahead. The driving route can be reached. In this configuration, the deviation of the distance from the extension direction line of the next travel route to the start point of the next travel route at the end of the final turning travel is allowed, and only the lateral deviation with respect to the extension direction line of the next travel route is suppressed. Since this is control, the control burden is less than steering control along a turning circle.

In one preferred embodiment of the present invention, the predetermined approach distance or the predetermined departure distance is a distance from the vehicle body to the next travel route in a direction perpendicular to the extension direction of the next travel route or the previous travel route. is the distance from the vehicle body to the preceding travel route in a direction perpendicular to the extending direction of the vehicle.

Since the coordinate position of the target travel route for automatic driving is stored in advance, the distance from the vehicle body to the previous travel route or the next travel route in the direction perpendicular to the extending direction is obtained using the coordinate position of the vehicle body. , is easily sought. The coordinate position of the vehicle body can be obtained using satellite positioning technology, inertial navigation technology, etc., which are used for automatic driving.

In one of the preferred embodiments of the present invention, a distance adjustment unit for adjusting the predetermined approach distance or the predetermined separation distance is provided, and the distance adjustment unit adjusts the minimum turning radius, turning speed, working width, Adjusting the predetermined approach distance or the predetermined departure distance based on at least one ground condition.

The predetermined approach distance or predetermined separation distance for accurately reaching the next travel route may fluctuate depending on the state of traveling devices such as crawlers and wheels and the state of the work site. With this configuration for coping with such fluctuations, accurate turning travel is realized regardless of the state of the traveling device of the work vehicle and the state of the work site.

In one preferred embodiment of the present invention, the starting steering degree is the maximum steering degree, and in another preferred embodiment, the final steering degree is the maximum steering degree.

If the steering degree is maximized, the turning space will be smaller and the turning travel time will be shorter. Of course, both the starting steering degree and the final steering degree may be the maximum steering degree.

In one preferred embodiment of the present invention, the starting steering control section, the final steering control section, a first turning mode steering section that performs a first turning mode, which is turning steering based on a predetermined turning speed, a second turning mode steering unit that controls a turning steering angle more finely than the first turning mode steering unit and performs a second turning mode, which is turning steering with a lower turning speed than the first turning mode steering unit; A turning mode selector for selecting either the turning mode or the second turning mode is provided.

In addition to the turning steering control (steering mode) described above, the autonomous vehicle can be equipped with various turning modes. As other turning modes, there is a turning mode that realizes turning steering control according to the above-mentioned Patent Document 1 and Patent Document 2. Furthermore, a turning mode called MPC (Model Predictive Control), which achieves turning steering control with high accuracy but a heavy control load, can also be used. With this configuration, the advantages and disadvantages of turning steering control can be effectively utilized.

It is a side view of a rice transplanter equipped with an automatic steering system. It is a schematic diagram explaining the power transmission from an engine to a planting mechanism. It is a mimetic diagram explaining a travel route for automatic travel of a rice transplanter. FIG. 5 is a schematic diagram illustrating turning travel from a start turning travel to a final turning travel; It is a functional block diagram which shows the control system of a rice transplanter.

In the following, a rice transplanter that travels in a field will be described as an example of an embodiment of an autonomous working vehicle equipped with the automatic steering system of the present invention. In this embodiment, unless otherwise specified, "front" (the direction of arrow F shown in FIG. 1) means the front in the longitudinal direction (running direction) of the aircraft, and "rear" (the direction of arrow B shown in FIG. 1). ) means the rear in the longitudinal direction (running direction) of the fuselage. In addition, the left-right direction or the lateral direction means the left-right direction (machine width direction) perpendicular to the front-back direction of the machine body. shall mean the direction of orientation.

[Overall structure]
As shown in FIG. 1, the rice transplanter has a vehicle body 1 of riding type and four-wheel drive type. The vehicle body 1 includes a parallel quadruple link type link mechanism 13, a hydraulic elevating cylinder 13a, a seedling planting device 3A, a fertilizing device 3B, and the like. The link mechanism 13 is connected to the rear portion of the vehicle body 1 so as to be vertically swingable. The elevating cylinder 13a drives the link mechanism 13 to swing. 3 A of seedling planting apparatuses are connected with the rear-end part of the link mechanism 13 so that rolling is possible. The fertilizing device 3B extends from the rear end of the vehicle body 1 to the seedling planting device 3A. In this embodiment, the seedling planting device 3A and the fertilizing device 3B are working devices 3 provided in the automatic traveling working vehicle of the present invention.

The vehicle body 1 includes a wheel-type traveling device 12, an engine 2A, and a hydraulic continuously variable transmission 2B. The continuously variable transmission 2B is a main transmission. The continuously variable transmission 2B is, for example, an HST (Hydro-Static Transmission). The continuously variable transmission 2B changes the speed of the power (rotational speed) output from the engine 2A by adjusting the angles of the motor swash plate and the pump swash plate. The traveling device 12 has left and right front wheels 12A and left and right rear wheels 12B. The left and right front wheels 12A function as steering wheels for changing the orientation of the vehicle. The left and right rear wheels 12B cannot be steered.

As shown in FIG. 1, a driving section 14 is provided at the rear portion of the vehicle body 1 . The driving unit 14 includes a steering wheel 10 for steering the front wheels, a main shift lever 7A, an auxiliary shift lever 7B, a work operation lever 11, and a driver's seat 16 for passengers (drivers, workers, managers). , etc. The main shift lever 7A adjusts the vehicle speed by shifting the continuously variable transmission 2B. The sub-transmission lever 7B enables the shift operation of the sub-transmission. The work operation lever 11 performs elevating operation of the seedling planting device 3A. Further, a preliminary seedling storage device 17A is supported by a preliminary seedling support frame 17 in front of the operating section 14. As shown in FIG. The spare seedling storage device 17A stores spare seedlings.

The steering wheel 10 is connected to the front wheels 12A via a steering mechanism (not shown). The steering angle of the front wheels 12A is adjusted by rotating the steering wheel 10. FIG. A steering motor M1 is connected to the steering mechanism. During automatic steering, the steering motor M1 operates based on a steering signal to adjust the steering angle (steering degree) of the front wheels 12A. Further, in the present embodiment, a shift operation motor M2 is provided for automatically operating the main shift lever 7A. During automatic running, the shift position of the continuously variable transmission 2B is adjusted by operating the shift operation motor M2 based on the shift signal.

As shown in FIG. 2, the seedling planting device 3A is illustrated in an eight-row planting format as an example. The seedling planting device 3A may be of other types such as a 6-row planting type or a 10-row planting type. Power from the engine 2A is distributed to each planting mechanism 22 via the planting clutch C0 and each row clutch EC. The planting clutch C0 switches the driving state of the seedling planting device 3A by switching on and off power transmission from the engine 2A. Each row clutch EC is configured to be able to select driving or non-driving of each planting mechanism 22 every two rows in the seedling planting device 3A. By controlling each row clutch EC, the seedling planting device 3A can be changed to two-row planting, four-row planting, six-row planting, and eight-row planting.

As shown in FIGS. 1 and 2, the seedling planting device 3A includes a seedling platform 21, a planting mechanism 22, and the like. The seedling mounting table 21 is a pedestal on which 8 rows of mat-like seedlings are mounted. The seedling mounting table 21 reciprocates in the horizontal direction with a constant stroke amount corresponding to the lateral width of the mat-like seedling. Each time the seedling platform 21 reaches the left and right stroke ends, each mat-like seedling on the seedling platform 21 is longitudinally fed toward the lower end of the seedling platform 21 at a predetermined pitch. The eight planting mechanisms 22 are of a rotary type and are arranged in the left-right direction at regular intervals corresponding to the intervals between the planting rows. Power from the engine 2A is transmitted to each planting mechanism 22 . Each planting mechanism 22 cuts off one seedling (planted seedling) from the lower end of each mat-like seedling placed on the seedling mounting table 21 by the power from the engine 2A, and places it on the mud part after leveling. Plant. As a result, the seedling planting apparatus 3A can take out seedlings from the mat-like seedlings placed on the seedling placement table 21 and plant them in the mud part of the paddy field in the operating state.

The fertilizing device 3B has a hopper 25, a delivery mechanism 26, and a fertilizing hose 28. The hopper 25 stores granular or powdery fertilizers (chemicals and other agricultural materials). A delivery mechanism 26 delivers fertilizer from the hopper 25 . The fertilizing hose 28 conveys the fertilizer delivered by the delivery mechanism 26 and discharges the fertilizer to the field. Fertilizer stored in the hopper 25 is delivered by a delivery mechanism 26 by a predetermined amount and sent to the fertilizing hose 28, conveyed through the fertilizing hose 28 by the carrying wind of the blower 27, and discharged from the ditching device 29 to the field. be. Thus, the fertilizing device 3B supplies fertilizer to the field.

The grooving machine 29 is arranged on the leveling float 15 . Each grooving device 29 ascends and descends together with each leveling float 15, forms a fertilizing groove in the muddy part of the paddy field, and guides the fertilizer into the fertilizing groove during work travel in which each leveling float 15 touches the ground. The grading float 15 functions as a ground sensor.

The communication terminal 9 that is detachably attached to the driving unit 14 is composed of, for example, a tablet computer. The communication terminal 9 can output various types of information to the operator as visual information and auditory information, and can accept inputs of various types of information. The communication terminal 9 is wirelessly or wiredly connected to the control system of the rice transplanter so that data can be exchanged. Various functions for automatic driving are installed in the communication terminal 9 . For example, it is possible to remotely control the control system (control unit 100) of the rice transplanter at a position away from the rice transplanter.

Furthermore, the rice transplanter is equipped with a positioning unit 8. The positioning unit 8 outputs positioning data for calculating the position and orientation of the vehicle body 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 three-axis tilt and acceleration of the vehicle body 1 . The positioning unit 8 is supported on top of the preliminary seedling support frame 17 .

[Travel route]
Working traveling in which the rice transplanter performs seedling planting work in a field by automatic traveling will be described with reference to FIG. 3 .

The rice transplanter in this embodiment can selectively execute manual running and automatic running. In manual traveling, the driver manually operates (including remote control operation) the steering wheel 10, the main gearshift lever 7A, the sub gearshift lever 7B, the work operation lever 11, etc. to perform work traveling. In automatic travel, the rice transplanter automatically travels and works along a preset target travel route.

When the rice transplanter performs the seedling planting work, the driver first runs the rice transplanter manually along the outer circumference (outer edge) of the field without performing work. As shown in FIG. 3, by this round trip, the outer peripheral shape of the farm field (field map) is generated, and the farm field is divided into the outer peripheral area OA and the inner area IA.

When the field map is generated, a travel route that the rice transplanter uses for automatic travel is generated.
In the inner area IA, a plurality of linear running paths (hereinafter referred to as straight running paths, but not necessarily limited to straight lines) extending substantially parallel to one side of the field are generated. This straight travel route is a travel route for the rice transplanter to travel throughout the entire inner area IA for work. Automatic steering in automatic driving is performed using this straight travel route as a target travel route. Each straight travel route is connected by a U-shaped turning travel route (substantially a 180-degree turning route). Automatic driving control consisting of automatic steering and automatic transmission is performed.

In the outer peripheral area OA, one or more round traveling routes are generated that go around the outer peripheral area OA along the outer periphery (outer edge) of the farm field. For example, in the example of FIG. 3, the circular traveling route consists of two circular traveling routes, inner and outer. The inner and outer circular travel routes can also be automatically traveled, but one or both of them may be manually traveled.

[Turn steering]
FIG. 4 shows a 180-degree turning travel path TL for transitioning from the previous travel path Lf, which is the straight travel route used for the previous work travel, to the next travel path Ln, which is the straight travel route used for the next work travel. An example is shown.

This 180-degree turning travel route TL consists of a starting turning travel route TL1, a final turning travel route TL2, and an intermediate travel route TL0. In FIG. 4, D indicates the distance between the previous travel route Lf and the next travel route Ln. Further, the azimuth of the straight travel route, which is the direction in which the previous travel route Lf and the next travel route Ln extend, is assumed to be the longitudinal azimuth AZ1, and the azimuth perpendicular to the azimuth of the straight travel route is assumed to be the lateral azimuth AZ2.

The starting turning travel path TL1 indicates a starting turning travel of 90 degrees from the end point of the previous traveling path Lf or an extension line of the previous traveling path Lf toward the next traveling path Ln, and the turning steering angle at that time is the starting steering angle. , is preset, but the maximum steering angle is preferred. The start turning travel ends when the vehicle body azimuth becomes the lateral azimuth AZ2 (when the vehicle body 1 turns 90 degrees), the steering angle is returned to the neutral steering angle (neutral steering degree), and the intermediate travel route TL0 is reached. Running (straight running) is started.

In intermediate travel, when the distance from the vehicle body 1 to the next travel route Ln reaches the predetermined approach distance D1, or when the distance from the previous travel route Lf to the vehicle body 1 reaches the predetermined separation distance D2, the final turning travel route TL2 is reached. The final turning run indicated by is started. In this embodiment, the predetermined approach distance D1 is the distance from the vehicle body 1 to the next travel route Ln in the lateral direction AZ2, which is the direction orthogonal to the extending direction of the next travel route Ln. The predetermined detachment distance D2 is the distance from the vehicle body 1 to the preceding travel route Lf in the lateral direction AZ2, which is the direction orthogonal to the extending direction of the preceding travel route Lf. Intermediate travel is omitted when the distance D between the previous travel route Lf and the next travel route Ln is short.

The final steering angle, which is the turning steering angle in the final turning travel, is set in advance, but the maximum steering angle is preferred. The final turning run ends when the azimuth of the vehicle body 1 becomes the longitudinal azimuth AZ1. When the final turning travel is ideally performed, the vehicle body 1 is positioned on the previous travel route Lf or an extension of the previous travel route Lf at the end of the final turning travel. If the position of the vehicle body 1 deviates from the preceding travel route Lf or the extension of the preceding travel route Lf in the lateral direction AZ2, the automatic steering control for the straight travel route is activated to correct the deviation. That is, when the final turning travel is completed, a route search is performed for the next travel route Ln, the next travel route Ln is captured, and automatic steering is performed using this as the target travel route.

The final steering angle used in the final turning run is set in advance, but the maximum steering angle is preferred. The target of the predetermined approach distance D1 or the predetermined departure distance D2 is such that the orientation of the vehicle body 1 coincides with the longitudinal orientation AZ1 by the final turning using the final steering angle, that is, coincides with the extension direction line of the next traveling route n. As such, it is statistically calculated and set by repeating experiments and simulations using actual machines. Of course, the predetermined approach distance D1 or the predetermined departure distance D2 can be adjusted in order to deal with the field conditions and aging of the steering system including the travel device 12 each time. Similarly, the starting steering angle and final steering angle can also be adjusted.

Fig. 5 shows a control block diagram of the control system of this rice transplanter. The control system of the rice transplanter consists of a control unit 100 that controls various operations of the rice transplanter and a communication terminal 9 that can exchange data with the control unit 100 . Signals from the positioning unit 8 , the manual operation tool sensor group 31 , the travel sensor group 32 , and the work sensor group 33 are input to the control unit 100 . A control signal from the control unit 100 is output to the traveling equipment group 1A and the work equipment group 1B.

The control unit 100 acquires positioning data for calculating the position and orientation of the vehicle body 1 (orientation in the longitudinal direction of the vehicle body) from the satellite positioning module 8A of the positioning unit 8. Acquire inertial measurement data about the tilt and acceleration of the

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 unit 100, the steering angle is adjusted by controlling the steering motor M1. Further, the vehicle speed is adjusted by controlling the speed change operation motor M2.

The work equipment group 1B includes, for example, an elevating cylinder 13a, a seedling amount adjusting device, a feeding amount adjusting device, and an on/off control device for the planting clutch C0 and each row clutch EC. The elevating cylinder 13a elevates the seedling planting device 3A. The seedling amount adjusting device adjusts the amount of seedlings taken by the planting mechanism 22 . The delivery amount adjusting device changes the amount of fertilizer delivered by the delivery mechanism 26 .

The manual operating tool sensor group 31 includes sensors, switches, and the like that detect the operating states of various manual operating tools. The traveling sensor group 32 includes various sensors for detecting conditions such as steering angle, vehicle speed, engine speed, and set values for them. The work sensor group 33 includes various sensors for detecting the states of the link mechanism 13, the seedling planting device 3A, and the fertilizing device 3B.

The control unit 100 includes a travel control unit 6, a work control unit 51, a vehicle body position calculation unit 52, a travel route setting unit 53, and a travel locus management unit 54.

The vehicle body position calculation unit 52 calculates map coordinates (body position) of the vehicle body 1 based on satellite positioning data and inertial navigation data sequentially sent from the positioning unit 8 . The map coordinates may be coordinates in a field coordinate system or a specific coordinate system as well as latitude and longitude.

In this embodiment, the communication terminal 9 is provided with a touch panel interface 90, an agricultural field information storage unit 91, a travel route map generation unit 92, a travel route generation unit 93, a remote control unit 94, and the like. The touch panel interface 90 is a graphic interface and has a function of displaying and inputting information through a touch panel provided in the communication terminal 9 . Therefore, this communication terminal 9 can function as an input/output interface for information and data of the control unit 100 .

The farm field information storage unit 91 stores information about the farm field, such as the entrance (exit) position of the farm field and the positions where seedlings and fertilizer can be supplied. The travel route map generator 92 generates a map of the farm field based on the travel locus obtained by causing the vehicle body 1 to travel along the outermost periphery of the outer peripheral area OA (see FIG. 3) of the farm field, that is, along the boundary line with the ridge. Calculate the external dimensions. The travel route generation unit 93 divides the field into an outer peripheral area OA and an inner area IA based on the outer dimensions of the field, and generates a travel route for automatic travel. The travel route, as shown in FIG. 3, consists of a circular travel route for travel in the outer peripheral area OA and a straight travel route for travel in the central area. The generated travel route is sent to the control unit 100 .

The remote control unit 94 has a program that causes the communication terminal 9 to function as a remote control for operating the rice transplanter. When the remote controller 94 operates, the administrator uses a hardware switch attached to the communication terminal 9 or a software switch displayed on the touch panel of the communication terminal 9 to remotely operate the control system (control unit 100) of the rice transplanter. can.

A travel route setting unit 53 built in the control unit 100 receives and manages the travel route generated by the travel route generation unit 93 from the communication terminal 9, and sets a target travel route for route following steering control. The travel route is set in sequence.

The travel locus management unit 54 generates and stores the travel locus of the vehicle body 1 based on the vehicle body position calculated by the vehicle body position calculation unit 52 .

The work control unit 51 automatically controls the work equipment group 1B based on a program given in advance during automatic travel, and controls the work equipment group 1B based on the driver's operation during manual travel.

The travel control unit 6 includes an automatic travel control unit 6A, a manual travel control unit 6B, and a control management unit 6C. This rice transplanter can be switched between an automatic running mode for automatic running and a manual running mode for manual running. The control management unit 6C receives a signal from a manual operation tool sensor (one of a group of manual operation tool sensors) that detects the state of a driving mode switching operation tool (not shown) and a switching signal generated by the control unit 100 in a controlled manner. Based on this, either the automatic driving mode or the manual driving mode is selected.

The manual travel control unit 6B that operates in the manual travel mode controls the steering motor M1 based on the amount of operation of the steering wheel 10, and based on the operation of manual operation tools such as the main shift lever 7A and the sub shift lever 7B. , to control the shift operation motor M2.

The automatic travel control unit 6A that operates in the automatic travel mode includes a route following steering unit 61 and an automatic turning steering unit 62. The route following steering unit 61 performs route following control so that the vehicle body 1 travels along the target travel route set by the travel route setting unit 53 . In the route following control, the route following steering section 61 uses the vehicle body position calculated by the vehicle body position calculation section 52 to determine the positional deviation of the vehicle body 1 with respect to the target travel route (lateral deviation relative to the target travel route) and the azimuth deviation of the vehicle body 1 (target deviation angle of the vehicle azimuth with respect to the azimuth of the travel route). In the route following control, the route following steering section 61 executes steering control so as to reduce the positional deviation and the azimuth deviation.

The turning automatic steering section 62 performs steering control for turning for turning the vehicle body 1, for example, for turning 90 degrees or 180 degrees. In particular, the turning automatic steering unit 62 has a start steering control unit 621, a final steering control unit 622, an intermediate steering control unit 623, a distance It has a determination unit 624 , a distance adjustment unit 625 and a turning mode selection unit 626 .

With reference to FIG. 4, the function of the turning automatic steering unit 62 in the turning traveling that connects the straight traveling paths (the previous traveling path Lf and the next traveling path Ln) will be described. The turning travel here is a 180-degree turning travel. The start steering control unit 621 controls the start turning travel for turning toward the next travel route Ln after the vehicle body 1 finishes traveling on the previous travel route Lf. At that time, the starting steering degree is set as the turning steering degree in order to perform the starting turning travel. This starting turning travel is a 90-degree turn, and ends when the vehicle body azimuth becomes the lateral azimuth AZ2 (when the azimuth change of the vehicle body 1 reaches 90 degrees). When the start turning travel ends, the steering control is taken over by the intermediate steering control section 623 . The intermediate steering control unit 623 returns the steering angle to the neutral steering angle, and causes the vehicle body 1 to travel in the lateral direction AZ2.

The distance determination unit 624 records the predetermined approach distance D1 or the predetermined separation distance D2. The distance determination unit 624 determines when the distance from the vehicle body 1 to the next travel route Ln in the lateral direction AZ2 reaches a predetermined approach distance D1, or when the distance from the previous travel route Lf to the vehicle body 1 in the lateral direction AZ2 reaches a predetermined departure distance. When the distance D2 is reached, a final turning start command is given to the final steering control section 622 .

The final steering control unit 622, in response to the final turning start command from the distance determination unit 624, controls the start turning travel for the vehicle body 1 to turn toward the next travel route Ln in the longitudinal direction AZ1. At that time, the final steering degree is set as the turning steering degree in order to perform the final turning travel. The final turning run by the final steering control unit 622 ends when the azimuth of the vehicle body 1 matches or substantially matches the longitudinal direction AZ1.

The distance adjustment unit 625 adjusts the predetermined approach distance D1 or the predetermined separation distance D2 used by the distance determination unit 624. This adjustment may be made automatically based on at least one of turning performance, turning speed, and ground conditions at the work site, or based on lateral displacement of the vehicle body position relative to the next traveling path Ln at the end of the final turning travel. good. Of course, the distance may be adjusted by the administrator using a dial switch or the like provided on the vehicle body 1 , or the distance may be adjusted through the communication terminal 9 using the touch panel interface 90 of the communication terminal 9 .

Although the start steering angle and the final steering angle are set to the maximum steering angle in this embodiment, they can be changed to arbitrary steering angles.

When the final turning run by the final steering control unit 622 is completed, the steering control is handed over to the route following steering unit 61 . The route following steering unit 61 captures the next travel route Ln or an extension of the next travel route Ln, and performs steering control so that the vehicle body 1 rides on the next travel route Ln or the next travel route Ln. If the route following steering unit 61 cannot capture the next travel route Ln or the extension of the next travel route Ln, the vehicle is stopped.

In this embodiment, the turning automatic steering section 62 operates in a turning mode other than a turning mode (this is referred to as a first turning mode) in which the final turning travel start timing is determined using the above-described predetermined approach distance D1 or predetermined departure distance D2. It also has modes. For example, it is possible to use a turning mode in which a 90-degree turn is performed at a predetermined steering angle in the initial turning travel, and then a final turning travel is performed with the starting end of the next travel route Ln as the travel target point. Alternatively, the turning mode disclosed in Patent Document 1 and Patent Document 2 can also be used. Furthermore, as a more accurate turning mode, turning traveling using MPC (model predictive control) can also be used. The turning mode selection unit 626 registers such turning modes as a second turning mode, a third turning mode, and a further turning mode, and selects a turning mode to be executed from among these. This selection is made automatically or manually. Furthermore, it is also possible to set in advance depending on the turning location. In FIG. 5, the functional portion that performs turning steering in the first turning mode is indicated as a first turning mode steering portion 62A. In FIG. 5, the functional portion that performs turning steering in the second turning mode is indicated as a second turning mode steering portion 62B. In FIG. 5, the functional portion that performs turning steering in the third turning mode is indicated as a third turning mode steering portion 62C.

[Another embodiment]
The present invention is not limited to the configurations exemplified in the above-described embodiments, and other representative embodiments of the present invention will be exemplified below.

(1) In the above-described embodiment, a rice transplanter is used as an automatic traveling working vehicle equipped with the automatic steering system of the present invention. It can also be applied to automatic traveling work vehicles such as lawn mowers and ground levelers.

(2) In the above-described embodiment, a turn pattern is taken in which the vehicle moves from the previous travel route Lf to the next travel route Ln via a 180-degree turn travel. The present invention is not limited to this embodiment, and the present invention can also be applied to turning travel at other angles, for example, a turning pattern consisting of a 45-degree start turning travel and a 45-degree final turning travel. Furthermore, the turning angles of the starting turning travel and the final turning travel may be different.

(3) In the above-described embodiment, the travel device 12 is of the steering wheel type, but may be of the crawler type.

(4) The functional block described using FIG. 5 is an example, and each functional unit is integrated with other functional units, each functional unit is divided into a plurality of functional units, and the control unit Various modifications are possible, such as 100 being distributed over multiple control subunits.

It should be noted that the configurations disclosed in the above embodiments (including other embodiments, the same shall apply hereinafter) can be applied in combination with configurations disclosed in other embodiments as long as there is no contradiction. Moreover, the embodiments disclosed in this specification are merely examples, and the embodiments of the present invention are not limited thereto, and can be modified as appropriate without departing from the scope of the present invention.

The automatic steering system of the present invention can be applied to an automatic traveling work vehicle that moves from the previous traveling route to the next traveling route through turning.

1: Vehicle body 3: Work device 8: Positioning unit 51: Work control unit 52: Vehicle position calculation unit 53: Travel route setting unit 6: Travel control unit 6A: Automatic travel control unit 6B: Manual travel control unit 6C: Control management unit 61: Route following steering unit 62: Turning automatic steering unit 62A: First turning mode steering unit 62B: Second turning mode steering unit 62C: Third turning mode steering unit 621: Start steering control unit 622: Final steering control unit 623: Intermediate steering control unit 624 : Distance determination unit 625 : Distance adjustment unit 626 : Turning mode selection unit 9 : Communication terminal 93 : Travel route generation unit 94 : Remote control unit 100 : Control unit AZ1 : Longitudinal direction AZ2 : Lateral direction D1 : Predetermined approach Distance D2: Predetermined departure distance Lf: Previous travel route Ln: Next travel route OA: Outer peripheral area TL0: Intermediate travel route TL1: Starting turning travel route TL2: Final turning travel route

Claims

An automatic steering system for an automatic traveling work vehicle that transitions from a previous traveling route to a next traveling route through turning traveling,
a start steering control unit for setting a start steering degree as a turning steering degree for starting turning travel in the turning travel;
When the distance from the vehicle body to the next travel route reaches a predetermined approach distance after the end of the start turning travel by the start steering degree, or when the distance from the previous travel route to the vehicle body reaches a predetermined separation distance. and a final steering control unit for setting a final steering degree as the turning steering degree of the final turning travel performed when the automatic steering system.
The preceding travel route and the next travel route are target travel routes extending parallel to each other, and the turning travel is a 180 degree turning travel,
2. The start steering control unit shifts the steering degree from the start steering degree to the neutral steering degree before or when the vehicle body orientation change in the start turning travel reaches 90 degrees. The automatic steering system as described in .
3. The predetermined approach distance or the predetermined separation distance is set so that the bearing of the vehicle body coincides with the extension direction line of the next travel route by the final turning travel using the final steering degree. The automatic steering system according to .
The predetermined approach distance or the predetermined separation distance is a distance from the vehicle body to the next travel route in a direction perpendicular to the extension direction of the next travel route or from the vehicle body in a direction perpendicular to the extension direction of the previous travel route. 4. The automatic steering system according to any one of claims 1 to 3, wherein the distance is the distance to the previous travel route.
A distance adjustment unit that adjusts the predetermined approach distance or the predetermined separation distance is provided,
5. The distance adjustment unit adjusts the predetermined approach distance or the predetermined separation distance based on at least one of a minimum turning radius, turning speed, working width, and ground conditions of the work site. Automatic steering system according to paragraph.
The automatic steering system according to any one of claims 1 to 5, wherein at least one of the starting steering degree and the final steering degree is a maximum steering degree.
the start steering control section, the final steering control section, and a first turning mode steering section that performs a first turning mode, which is turning steering based on a predetermined turning speed;
a second turning mode steering unit that controls a turning steering angle more finely than the first turning mode steering unit and performs a second turning mode that is turning steering with a lower turning speed than the first turning mode steering unit;
The automatic steering system according to any one of claims 1 to 6, further comprising a turning mode selection section that selects one of the first turning mode and the second turning mode.