Automatic driving control system

Abstract

To perform an automatic driving along a target drive route with high accuracy.SOLUTION: An automatic driving control system for a work vehicle that automatically drives along a target drive route TL, includes: a situation acquisition unit 50 that acquires a manual driving situation when the work vehicle is manually driven; and a drive control unit 37 that performs automatic driving control so that the work vehicle drives along the target drive route TL based on at least a vehicle position P and a drive direction. The target drive route TL generated by a drive route calculation unit 35 includes a previously traveled drive route generated based on a traveled trajectory along which the work vehicle has been driven manually in advance, and a driving control unit 37 has a steering consideration mode in which, when driving along the previously traveled drive route, driving is controlled based on the manual driving situation in addition to the vehicle position P.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to an automatic driving control system for controlling the automatic driving of a work vehicle that performs automatic driving along a target travel route.

Background Art

[0002] As disclosed in Patent Document 1, a work vehicle such as a rice transplanter performs work while automatically driving along a target travel route generated in a field. Here, the target travel route includes a bent portion, and the work vehicle changes its traveling direction at the bent portion. When the work vehicle reaches the bent portion (the start position of the traveling direction change), automatic steering control is performed so that the work vehicle travels along the target travel route.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, at a portion that bends abruptly, it may be difficult to perform automatic steering control, and the work vehicle may deviate from the target travel route and may not be able to perform automatic driving appropriately.

[0005] An object of the present invention is to accurately perform automatic driving along a target travel route.

Means for Solving the Problems

[0006] An automatic driving control system according to one embodiment of the present invention is an automatic driving control system for a work vehicle that automatically drives along a target driving path, comprising: a machine position calculation unit that calculates the position and driving direction of the machine body of the work vehicle; a status acquisition unit that acquires the manual driving status when the work vehicle is driven manually; a storage unit that stores the acquired manual driving status; a driving path calculation unit that generates the target driving path; and a driving control unit that performs automatic driving control so that the work vehicle drives along the target driving path based on at least the position and driving direction of the machine body, wherein the target driving path generated by the driving path calculation unit includes a previously driven driving path generated based on the driving trajectory of the work vehicle driven manually in advance, and the driving control unit controls the driving based on the position of the machine body in addition to the manual driving status when driving along the previously driven path. Furthermore, in order to achieve the above objective, an automatic driving control system according to one embodiment of the present invention is an automatic driving control system for a work vehicle that automatically drives along a target driving path, comprising: a vehicle position calculation unit that calculates the position and driving direction of the vehicle; a status acquisition unit that acquires at least one of the steering conditions, wheel conditions, and vehicle direction conditions when the work vehicle is driven manually; a storage unit that stores at least one of the acquired steering conditions, wheel conditions, and vehicle direction conditions; and a plurality of path elements and a target direction indicating the direction of travel of the vehicle in each of the path elements. The system comprises a travel path calculation unit that generates the target travel path, and a travel control unit that performs automatic travel control so that the work vehicle travels along the target travel path based on at least the position of the machine and the direction of travel, wherein the target travel path generated by the travel path calculation unit includes a previously traveled travel path generated based on the travel trajectory previously traveled by the work vehicle manually, and the travel control unit has a steering consideration mode that, when traveling along the previously traveled travel path, controls the travel by considering at least one of the steering conditions, wheel conditions, and machine direction conditions in addition to the position of the machine.

[0007] The previously traveled path is generated as an approximate straight line of the travel trajectory. Therefore, points where the direction of travel changes become intersections of straight path elements (previously traveled paths), which may necessitate a sudden change of direction, and it may be difficult to change direction along the path elements. In other words, if the path elements are located outside the trajectory of the direction change in manual driving, driving along the path elements may result in a delay in changing direction.

[0008] By considering at least one of the steering conditions, wheel conditions, and aircraft heading conditions during manual driving when changing direction, delays in changing direction can be suppressed even on routes with abrupt changes in direction, enabling accurate automated driving along the target route.

[0009] Furthermore, the steering condition may be the operating angle of the steering handle that accepts steering input to the work vehicle, the wheel condition may be the steering angle of the front wheels of the work vehicle, and the vehicle orientation condition may be the change in the direction of travel of the vehicle along the travel trajectory.

[0010] By considering at least one of the following: the operating angle of the steering handle 10 used for manual steering, the steering angle of the front wheels, and the change in the direction of travel of the vehicle along the trajectory, it is possible to initiate a change in direction of travel at a position consistent with manual driving, thereby suppressing delays in changing direction of travel and enabling accurate automatic driving along the target travel path.

[0011] Furthermore, it is preferable that the driving control unit performs the automatic driving control using the steering consideration mode when changing the direction of travel of the vehicle along the previously traveled path.

[0012] This allows the system to take steering conditions and other factors into account when changing direction, which requires careful consideration, enabling highly accurate automated driving along the target route.

[0013] Furthermore, the driving control unit may perform the automatic driving control using the steering consideration mode if the angle formed by the path elements before and after the starting position of the change in the direction of travel is greater than or equal to a predetermined angle.

[0014] The point at which the start of a change of direction is delayed relative to the target travel path is where abrupt changes of direction occur. These abrupt changes of direction occur where the angle between the path elements before and after the point of change of direction is large.

[0015] Therefore, with the above configuration, it is possible to switch to steering-aware mode at appropriate points, enabling highly accurate automatic driving along the target driving path.

[0016] Furthermore, the driving control unit may perform the automatic driving control using the steering consideration mode if the angle formed by the target direction in the path elements before and after the starting position of the change in the direction of travel is greater than or equal to a predetermined angle.

[0017] The points where abrupt changes in direction occur are those where the angle between the target bearings in the path elements before and after the point of change in direction is large. Therefore, with the above configuration, it is possible to switch to steering-considering mode at appropriate points, enabling highly accurate automatic driving along the target driving path.

[0018] Furthermore, when the driving control unit performs the automatic driving control using the steering consideration mode, it is preferable to control the automatic driving control to start from before the starting position of the change in the direction of travel along the target driving path.

[0019] This configuration suppresses delays in initiating changes in direction, enabling highly accurate automated driving along the target route.

[0020] Furthermore, when the driving control unit performs the automatic driving control using the steering consideration mode, it may correct the target driving path based on at least one of the steering conditions, the wheel conditions, and the vehicle orientation conditions.

[0021] With such a configuration, since the vehicle automatically travels (automatic steering) along the target travel route in consideration of the steering situation and the like, it becomes possible to accurately perform automatic travel along the target travel route.

[0022] Further, the travel route calculation unit generates a direction change route as the target travel route from the forward travel trajectory and the backward travel trajectory during forward travel when changing the traveling direction among the travel trajectories, and the travel control unit may perform the automatic travel control so that the work vehicle travels along the direction change route when changing the traveling direction.

[0023] With such a configuration, since the vehicle automatically travels (automatic steering) along the direction change route in consideration of the steering situation and the like, it becomes possible to accurately perform automatic travel along the target travel route.

Brief Description of Drawings

[0024] [Figure 1] It is a left side view of a rice transplanter capable of automatic travel. [Figure 2] It is a diagram illustrating the configuration of a functional block related to automatic work travel. [Figure 3] It is a schematic diagram explaining the work travel of the rice transplanter. [Figure 4] It is a diagram explaining the change of the traveling direction and the generation of the outer circumferential route in the circular travel. [Figure 5] It is a diagram explaining the change of the traveling direction and the generation of the outer circumferential route in the circular travel. [Figure 6] It is a diagram explaining the position of the vehicle body. [Figure 7] It is a diagram explaining the automatic travel along the target travel route. [Figure 8] It is a diagram explaining an example of the generation of the direction change route. [Figure 9] It is a diagram explaining an example of the generation of the direction change route. [Figure 10] It is a diagram explaining the covering ratio. [Figure 11]This diagram illustrates an example configuration for generating a composite target orientation in a divided path element. [Modes for carrying out the invention]

[0025] In the following, the present invention will be described using a rice transplanter that automatically plants seedlings in the field floor level while driving.

[0026] Here, for the sake of ease of understanding, in this embodiment, unless otherwise specified, "front" (direction of arrow F in Figure 1) means the front in the longitudinal direction (travel direction) of the aircraft, and "rear" (direction of arrow B in Figure 1) means the rear in the longitudinal direction (travel direction) of the aircraft. Also, the left-right direction or lateral direction means the transverse direction (aircraft width direction) of the aircraft that is perpendicular to the longitudinal direction of the aircraft, "left" means the direction towards the viewer in Figure 1, and "right" means the direction towards the back of the page in Figure 1.

[0027] [Overall structure] As shown in Figure 1, the rice transplanter is a ride-on type with a four-wheel drive system. The system includes a parallel four-link link mechanism 13 that is vertically swingable and connected to the rear of the system, a hydraulic lifting link 13a that swings the link mechanism 13, a seedling planting device 3 that is rollably connected to the rear end region of the link mechanism 13, and a fertilizer applicator 4 that is installed from the rear end region of the system to the seedling planting device 3.

[0028] The machine body 1 is equipped with wheels 12, an engine 2, and a hydraulic continuously variable transmission 9 as its main transmission mechanism. The continuously variable transmission 9 is, for example, an HST (Hydro-Static Transmission). The wheels 12 consist of steerable left and right front wheels 12A and non-steerable left and right rear wheels 12B. Power output from the engine 2 is transmitted to the continuously variable transmission 9 via the driving transmission mechanism, and from the continuously variable transmission 9 is transmitted to the front wheels 12A, rear wheels 12B, and work devices 1C (seedling planting device 3, fertilizer applicator 4, etc.). The engine 2 and the continuously variable transmission 9 are mounted at the front of the machine body 1.

[0029] The seedling planting device 3 is configured, for example, as an 8-row planting type. The seedling planting device 3 includes a seedling tray 21, an 8-row planting mechanism 22, etc. This seedling planting device 3 can be changed to a 2-row, 4-row, 6-row planting type, etc., by controlling each row clutch (not shown).

[0030] The seedling tray 21 is a base on which eight rows of mat-shaped seedlings are placed. The seedling tray 21 continuously moves back and forth (laterally) in the left-right direction with a constant stroke corresponding to the left-right width of the mat-shaped seedlings. Each time the seedling tray 21 reaches the left or right stroke end after a predetermined number of lateral movements, each mat-shaped seedling on the seedling tray 21 is moved vertically towards the lower end of the seedling tray 21 at a predetermined pitch (vertical movement amount). The eight planting mechanisms 22 are rotary type and are arranged in the left-right direction at constant intervals corresponding to the planting rows. Power is transmitted from the engine 2 when the planting clutch (not shown) is switched to the transmission state, and each planting mechanism 22 cuts off one seedling (planting seedling) from the lower end of each mat-shaped seedling placed on the seedling tray 21 and plants it in the muddy area after leveling at predetermined planting intervals. As a result, when the seedling planting device 3 is in operation, seedlings can be taken from the mat-shaped seedlings placed on the seedling tray 21 and planted in the muddy area of ​​the paddy field.

[0031] The fertilizer application device 4 includes a hopper 25 (storage section) for storing granular or powdered fertilizer, a dispensing mechanism 26 for dispensing fertilizer from the hopper 25, and a fertilizer application hose 28 for transporting the fertilizer dispensed by the dispensing mechanism 26 and discharging it to the field FL (see Figure 2). The fertilizer stored in the hopper 25 is dispensed in predetermined amounts by the dispensing mechanism 26 and sent to the fertilizer application hose 28, where it is transported through the fertilizer application hose 28 by the airflow from the blower 27 and discharged to the field FL from the furrower 29. In this way, the fertilizer application device 4 supplies fertilizer to the field FL.

[0032] As shown in Figure 1, the machine body 1 is equipped with an operating unit 14 in the rear area. The operating unit 14 includes a steering handle 10 for steering the front wheels, a main transmission lever 7A for adjusting the vehicle speed by operating the continuously variable transmission 9, a sub-transmission lever 7B for operating the sub-transmission, an operation lever 11 for raising and lowering the seedling planting device 3 and switching its operating state, a detachable information terminal 5 with a touch panel that displays (notifies) various information to the operator and accepts input of various information, and an operator's seat 16 for the operator (driver / worker). The sub-transmission lever 7B is used to switch the vehicle speed between the work speed during work and the travel speed during movement. For example, movement between fields is performed at the travel speed, and planting work is performed at the work speed. Furthermore, a spare seedling storage device 17A for storing spare seedlings is supported by a spare seedling support frame 17 in front of the operating unit 14.

[0033] Furthermore, the aircraft 1 is equipped with a positioning unit 8. The positioning unit 8 outputs positioning data for calculating the position and bearing of the aircraft 1. The positioning unit 8 includes a satellite positioning module 8A that receives radio waves from Global Navigation Satellite System (GNSS) satellites and an inertial measurement module 8B that detects the tilt and acceleration of the three axes of the aircraft 1. The positioning unit 8 is supported on top of the auxiliary seedling support frame 17. Based on the positioning data acquired by the positioning unit 8, the position P of the aircraft is intermittently calculated and stored.

[0034] [Autonomous driving] The automated operation of a rice transplanter, in which it performs seedling planting work on the field floor level (FL) using automatic driving, will be explained with reference to Figure 1 and Figures 2 to 7.

[0035] First, we will explain the configuration of the functions for automatic operation and movement of the rice transplanter using Figure 2.

[0036] The rice transplanter is equipped with a control unit 30 that controls automatic operation and movement within the machine body 1. The control unit 30 is capable of data communication with the positioning unit 8, steering wheel 10, wheels 12, work device 1C, etc. The control unit 30 includes a machine body position calculation unit 33, a travel path calculation unit 35, a travel control unit 37, a work control unit 38, and a storage unit 40.

[0037] The aircraft position calculation unit 33 acquires positioning data from the positioning unit 8 and, based on the positioning data, intermittently calculates the aircraft's position P and the aircraft's direction of travel at position P at predetermined intervals.

[0038] The travel path calculation unit 35 generates a field map based on the position P of the machine calculated during perimeter travel along the outer edge of the field FL. Furthermore, the travel path calculation unit 35 generates a target travel path TL for automatic travel. The target travel path TL includes multiple path elements, and each path element includes a target direction TD, which is the direction along the path element.

[0039] The driving control unit 37 performs steering control and drive control during automatic and manual driving. In steering control, the driving control unit 37 controls the front wheels 12A to travel along the target driving path TL during automatic driving, and controls the front wheels 12A in accordance with the driver's operation on the steering wheel 10 during manual driving. During automatic driving, the driving control unit 37 controls the driving direction of the vehicle 1 to match the target heading TD corresponding to the path element being traveled.

[0040] The work control unit 38 controls the operation of the work device 1C according to the operator's actions or a pre-set program.

[0041] The memory unit 40 stores various information such as the generated target travel path TL, a program for automatically controlling the work device 1C, and the position P of the machine.

[0042] Next, using Figures 2 to 7, we will explain a configuration that generates a target driving path TL and performs automatic driving (automatic steering) along the target driving path TL.

[0043] The rice transplanter in this embodiment can be selectively operated manually or automatically. Manual operation (manual work operation) and automatic operation (automatic work operation) are selected by switching the automatic / manual changeover switch (not shown) located on the driver's unit 14.

[0044] When a rice transplanter performs seedling planting, the operator first manually drives the transplanter along the outer perimeter (outer edge) of the field FL (outer edge travel). As shown in Figure 3, the travel path calculation unit 35 generates the outer perimeter shape (field map) of the field FL based on this outer edge travel, and divides the field FL into an outer perimeter area OA and an inner area IA. At this time, one or more specified sides of the outer perimeter of the field FL are set as supply sides SL for supplying the rice transplanter with agricultural materials such as mat-shaped seedlings, fertilizers, chemicals, and fuel.

[0045] As shown in Figures 2 to 5, once the field map is generated, the travel path calculation unit 35 sets a target travel path TL on which the rice transplanter will perform its work. The target travel path TL includes a plurality of path elements set on the target travel path TL, and a target direction TD (see Figure 7), which is the direction along the target travel path TL for each path element. The path elements are formed from straight lines (approximate straight lines) connecting at least two nodes LN. The nodes LN correspond to at least a portion of the machine's position P, which is calculated intermittently based on positioning data acquired by the positioning unit 8.

[0046] In the internal area IA, an internal round-trip path IPL and a turning path are generated as the target travel path TL. The internal round-trip path IPL is a path element that is approximately parallel to one side of the field FL, and the turning path is a path that connects two internal round-trip path IPLs. The internal round-trip path IPL is a travel path that covers the entire internal area IA. Automatic work travel is performed along the internal round-trip path IPL. Turning travel on the turning path that connects the internal round-trip path IPL is performed automatically using a predetermined method. Note that the internal round-trip path IPL may be curved, in which case the internal round-trip path IPL will contain multiple path elements.

[0047] In the outer perimeter area (OA), a circular planting operation is performed, circling the area OA one or more times along the outer perimeter (outer edge) of the field (FL). For example, two operating paths are generated as the target operating paths (target operating paths TL): the inner circular path (IRL) and the outer circular path (ORL). By performing the operation on the inner circular path (IRL) and the outer circular path (ORL), the entire operation of the outer perimeter area (OA) is completed. The inner circular path (IRL) is operated by unmanned automatic operation or manned automatic operation (automatic operation with a person on board), while the outer circular path (ORL) is operated by manual operation or manned automatic operation. Alternatively, depending on the mode selection, the inner circular path (IRL) may be operated by manual operation, or the outer circular path (ORL) may be operated by unmanned automatic operation.

[0048] Here, when manually driving around the outer perimeter of the field FL, if the direction of travel of the machine 1 is changed at a corner of the field FL (hereinafter simply referred to as "changing direction of travel"), the machine 1 will travel as follows. As illustrated in Figure 4, when changing direction of travel at a corner of the field FL, the machine 1 first travels along the outer perimeter of the field FL to the vicinity of the edge (corner) of the field FL. The vehicle's movement at this point is as shown by the trajectory ML1. Next, the vehicle 1 moves in reverse as shown by the trajectory ML2. Then, the vehicle 1 moves forward as shown by the trajectory ML3 as the steering wheel 10 is operated. Finally, the vehicle 1 moves in reverse as shown by the trajectory ML4 as the trajectory ML4 ends. Note that in Figure 4, reverse movement is shown by a dashed line. With this, the vehicle 1 has finished changing direction, and the vehicle 1 moves along the outer perimeter of the field FL as shown by the trajectory ML5, with the end position of the trajectory ML1 as the starting position of the trajectory ML5.

[0049] During outer perimeter travel, the aircraft position calculation unit 33 intermittently calculates the aircraft's position P based on positioning data acquired by the positioning unit 8 and stores it in the storage unit 40. Therefore, the aircraft's position P will be aligned with the travel trajectory (ML1~ML5). The travel path calculation unit 35 does not use the aircraft's position P in the travel trajectory (ML2~ML4) related to the change of direction of travel, but generates the outer perimeter route ORL from an approximate straight line (previously traveled route) calculated from node LN, which is at least a part of the aircraft's position P in travel trajectory ML1, and an approximate straight line (previously traveled route) calculated from node LN, which is at least a part of the aircraft's position P in travel trajectory ML5. Therefore, the outer perimeter route ORL will be a route that substantially coincides with travel trajectory ML1 and travel trajectory ML5. In other words, the outer loop route ORL is generated along the actual straight-line trajectories ML1 and ML5 during the outer loop, without considering the trajectories (ML2-ML4) related to changes in direction during the outer loop.

[0050] The travel path calculation unit 35 may extract nodes LN from the calculated aircraft position P in any way, or it may extract aircraft position P at predetermined intervals and use those as nodes LN. Alternatively, the travel path calculation unit 35 may generate straight lines connecting the aircraft position P in the order of travel, and based on the angles formed by adjacent straight lines, generate nodes LN by deleting aircraft position P where the angle formed by the straight lines is less than or equal to a predetermined value. In this case, if the aircraft 1 travels in a manner close to a straight line, nodes LN corresponding to the start and end positions will be generated in the generated path elements.

[0051] In addition to the corners of the field FL, the outer perimeter of the field FL may also bend, and changes in direction may occur along these bends. Furthermore, there may be obstacles such as water inlets (see Figure 9) at the edge of the field FL, and changes in direction may be necessary to avoid these obstacles during perimeter travel. For example, as shown in Figure 5, if the outer perimeter of the field FL is curved, the machine 1 will travel in a straight line along the outer perimeter of the field FL (travel trajectory ML6), then, near the curved part of the outer perimeter, the steering handle 10 will be operated to change the direction of travel by moving forward (travel trajectory ML7), and then it will travel in a straight line again along the outer perimeter of the field FL (travel trajectory ML8).

[0052] Even when outer perimeter travel is performed as illustrated in Figure 5, the travel path calculation unit 35 does not use the position P of the machine during travel involving a change in direction of travel, but instead generates the outer perimeter route ORL using at least a portion of the position P of the machine in travel trajectory ML6 and the position P of the machine in travel trajectory ML8, which are the positions of the machine during straight-line travel, as nodes LN. In other words, the outer perimeter route ORL is generated from an approximate straight line (previously traveled path) calculated from node LN in travel trajectory ML6 and an approximate straight line (previously traveled path) calculated from node LN in travel trajectory ML8.

[0053] In outer perimeter driving in areas where the outer edge of the field FL is curved, or in outer perimeter driving to avoid obstacles OB, changes in direction of travel are not limited to forward movement; changes in direction of travel may also be made by repeatedly moving forward and backward. In this case as well, the driving path calculation unit 35 does not use the position P (node ​​LN) of the machine related to the change in direction of travel to generate the outer perimeter route ORL, but generates the outer perimeter route ORL using the position P of the machine in the driving trajectory ML6 and the position P (node ​​LN) of the machine in the driving trajectory ML8.

[0054] Here, the outer loop route ORL is not limited to being generated based on the trajectory of the outer loop as described above, but may also be generated based on the generated field map, similar to the inner loop route IRL.

[0055] The aircraft position calculation unit 33 calculates the aircraft position by converting the positioning data acquired by the positioning unit 8 so that the center of gravity position CP of the aircraft 1 becomes the aircraft position P, as shown in Figure 6. Since automatic driving is performed based on the aircraft position P, this center of gravity position CP becomes the control point of the aircraft 1 during automatic driving. The center of gravity position CP of the aircraft 1 is, for example, the center of the rear axle.

[0056] As shown in Figure 7, when the vehicle is automatically traveling along the target travel path TL, the travel control unit 37 controls the automatic travel (automatic steering) based on the target heading TD for the path elements on the target travel path TL and the heading of the vehicle 1 while it is traveling along the path elements (the direction of travel of the vehicle 1). Specifically, the travel control unit 37 automatically steers the vehicle 1 so that the heading of the vehicle 1 (the direction of travel of the vehicle 1) matches the target heading TD for the path element corresponding to the position P of the vehicle while it is traveling.

[0057] In the example shown in Figure 7, the driving control unit 37 automatically steers the vehicle 1 so that its orientation (direction of travel) points towards the target orientation TD1 in the first path element TL1 while the vehicle is traveling along the first path element TL1 of the target travel path TL. When the vehicle 1 reaches the end position of the first path element TL1 (the start position of the second path element TL2), which is the position where the target orientation TD changes (a bend, the starting position of the change of direction), the driving control unit 37 automatically steers the vehicle 1 so that its orientation (direction of travel) points towards the target orientation TD2 in the second path element TL2. In this way, the vehicle 1 automatically travels along the target travel path TL.

[0058] As described above, the driving control unit 37 controls automatic driving along the target driving path TL based on the target heading TD and the driving direction of the vehicle 1 (the direction of travel of the vehicle 1). Since the target heading TD and the driving direction of the vehicle 1 are determined based on the position P of the vehicle while it is driving, steering control (change of direction of travel) based on the target heading TD2 in the second path element TL2 is started only when the vehicle 1 reaches the starting position (bending position, starting position for changing the direction of travel) of the second path element TL2. For this reason, steering control may start with a delay when driving in the second path element TL2 begins, and if the angle between the target headings TD of adjacent path elements (angle difference = bending angle), which corresponds to the angle between adjacent path elements, becomes large, the direction of travel may not be changed appropriately, and it may be difficult to drive along the path element, especially in the initial stages of driving after the change of direction of travel.

[0059] Therefore, when changing direction based on the target heading (TD), steering control is performed to ensure an appropriate change in direction. The following describes an embodiment of the steering control.

[0060] [Embodiment 1] The steering control according to Embodiment 1 will be described below with reference to Figures 2 to 5, 8, and 9.

[0061] In this embodiment, when the vehicle travels around the perimeter, the steering angle SA of the steering handle 10 is stored as the steering status along with the vehicle's position P. Then, when automatically traveling along a previously traveled route, automatic driving control (steering control) is performed taking the steering angle SA into consideration, at least when changing the direction of travel.

[0062] As shown in Figure 5, the vehicle may change direction from a straight line along the field FL to an arc-shaped change of direction, and then return to a straight line. Since a linear travel path is generated as the target travel path TL, this type of travel generates two linear outer circumferential paths ORL. However, when changing direction, the actual travel trajectory ML7 is located inside the outer circumferential path ORL, as indicated by the vehicle's position Pn. In other words, when traveling around the perimeter, the change of direction begins before the intersection of the two outer circumferential paths ORL. As a result, if steering control is performed along the outer circumferential path ORL, the change of direction will start from the intersection of the two outer circumferential paths ORL, causing a delay in the change of direction.

[0063] According to this embodiment, at least when changing direction, the steering angle SA of the steering wheel 10 during outer perimeter driving can be taken into consideration. Therefore, the position from which the steering wheel 10 begins to be operated can be taken into consideration, and steering control for changing direction can be started before the intersection of the two outer perimeter paths ORL (the starting position for changing direction). As a result, delays in steering control are suppressed, and it becomes possible to perform automatic driving along the target driving path TL with high accuracy.

[0064] Specifically, as shown in Figure 2, the control unit 30 further includes a steering condition acquisition unit 50 (condition acquisition unit).

[0065] The steering status acquisition unit 50 acquires the steering angle SA (steering status) of the steering handle 10 during manual driving around the outer perimeter, and stores it in the storage unit 40 in association with the position P of the vehicle.

[0066] The driving control unit 37 has a normal mode and a steering-considered mode when performing automatic driving. The normal mode is a mode in which steering control is performed so that the driving direction of the aircraft 1 matches the target heading TD corresponding to the path element at the aircraft's position P during driving. The steering-considered mode is a mode in which steering control is performed taking into account the steering angle SA in addition to the position P and driving direction of the aircraft 1, at least when changing the direction of travel.

[0067] During perimeter travel, when the machine 1 is traveling along the straight section of the outer perimeter of the field FL, the steering angle SA of the steering handle 10 is within the range of fine adjustment. During perimeter travel, when the machine 1 is traveling along a curved section of the outer perimeter of the field FL, the steering angle SA of the steering handle 10 becomes larger.

[0068] Therefore, when the vehicle is traveling along the outer loop path ORL, which is a previously traveled route, the driving control unit 37 refers to the steering angle SA corresponding to the vehicle's position P, which is stored in the memory unit 40. When the vehicle reaches a position where the steering angle SA is greater than or equal to a predetermined angle, or a predetermined distance before reaching that position, the control unit recognizes that this is an area where the direction of travel should be changed, and switches to steering consideration mode. The driving control unit 37 then starts steering control so that the direction of travel changes towards the target heading TD on the next outer loop path ORL (previously traveled route).

[0069] This allows the change of direction to begin earlier than the starting point of the change of direction, which is the intersection of adjacent outer circular paths (path elements). This suppresses delays in the start of the change of direction and enables accurate automatic driving along the outer circular path ORL after the change of direction.

[0070] Furthermore, the transition to the steering consideration mode is not limited to when the steering angle SA of the steering wheel 10 is greater than or equal to a predetermined angle, but may also occur when the amount of change in the steering angle SA of the steering wheel 10 per unit time exceeds a predetermined value.

[0071] Furthermore, the transition to the steering consideration mode is not limited to being based on the steering angle SA of the steering wheel 10, but may also be based on the target driving path TL, and the steering angle SA of the steering wheel 10 may be considered in the steering control in the steering consideration mode. In this case, the transition to the steering consideration mode is performed, for example, when the angle formed by the path elements before and after the intersection of adjacent outer circular paths ORL (path elements) (start position for changing direction), or the angle formed by the target heading TD corresponding to the path elements before and after the intersection of adjacent outer circular paths ORL (path elements) (start position for changing direction), is greater than or equal to a predetermined angle. When the angle formed by the path elements before and after the intersection of adjacent outer circular paths ORL (path elements), or the angle formed by the target heading TD, is greater than or equal to a predetermined angle, the driving control unit 37 transitions to the steering consideration mode and starts changing direction from before the start position for changing direction, taking the steering angle SA into consideration.

[0072] In addition, while we have described an example in steering-considered mode where the change of direction of travel begins before the intersection of adjacent outer circular paths ORL (path elements), in steering-considered mode, the starting position of the change of direction of travel is not changed, and the steering control to change the direction of travel of the aircraft 1 to the target heading TD on the outer circular path ORL after the change of direction may be performed more abruptly than in normal mode.

[0073] Furthermore, the steering consideration mode is activated when making any changes in direction of travel, such as changing direction at the corners of the field floor level (FL).

[0074] For example, as shown in Figure 4, at the corner of the field FL, the steering handle 10 is operated while the vehicle repeatedly moves forward and backward.

[0075] When the vehicle is automatically driving on the outer loop route ORL, which is a previously driven route, the driving control unit 37 can determine that a change in direction has occurred if it confirms that the steering wheel 10 has been operated while the vehicle is moving forward and backward, and can switch to steering-aware mode. Furthermore, in steering-aware mode, the driving control unit 37 can perform steering control such as starting steering control early or performing sharp steering, depending on the steering conditions, which are forward and reverse, and the amount of steering wheel 10 operation at that time (steering angle SA, change in steering angle SA, etc.).

[0076] [Another embodiment of Embodiment 1] (1) The steering consideration mode is not limited to a configuration that adjusts steering control, but may also be a configuration that corrects the target driving path TL. In other words, in order to perform automatic driving with high accuracy along the target driving path TL (outer circular path ORL) after the change of direction of travel, the driving control unit 37 may correct the outer circular path ORL (path elements) before and after the change of direction of travel based on the steering conditions so as to smoothly connect the outer circular path ORL (path elements) before and after the change of direction of travel.

[0077] For example, as shown in Figure 4, when traveling around the outer perimeter of a field (FL), the steering wheel 10 is operated along trajectories such as ML2, ML3, and ML4 to move forward and backward. However, the outer circumferential path ORL (path element) in the target travel path TL is determined as an approximate straight line of travel trajectories ML1 and ML5, as described above. Therefore, it can be difficult to change the direction of travel appropriately, and there have been cases where automatic driving along the target travel path TL with high accuracy could not be performed.

[0078] Furthermore, as shown in Figure 5, in areas where the outer perimeter of the field FL is curved, when driving around the outer perimeter, the steering wheel 10 is operated in a trajectory like the driving trajectory ML7 to change the direction of travel. However, as mentioned above, the outer circumferential path ORL (path element) in the target driving path TL is obtained as an approximate straight line of the driving trajectories ML6 and ML8. Therefore, it was difficult to change the direction of travel appropriately, and there were cases where automatic driving along the target driving path TL with good accuracy could not be performed.

[0079] In the steering-considering mode of this embodiment, the driving control unit 37 predicts the driving path during outer perimeter driving based on the operation status of the steering wheel 10 during outer perimeter driving. Then, based on the predicted driving path, the driving control unit 37 corrects the path elements before and after the change in direction of travel and the target heading TD so as to smoothly connect the path elements before and after the change in direction of travel.

[0080] With this configuration, even if the target heading TD changes abruptly at an intersection of the travel path, the target travel path TL is corrected so that the target heading TD changes gradually. This allows for appropriate changes in direction and accurate automatic driving along the target travel path TL.

[0081] (2) The steering consideration mode is not limited to a configuration that adjusts steering control, but may also be a configuration in which the target driving path TL when changing direction of travel is generated based on the steering conditions.

[0082] When generating a target driving path TL, the driving path calculation unit 35 reads the steering angle SA (steering condition) stored in the memory unit 40 and detects the points where the vehicle should change direction and switch to the steering consideration mode, as described above. When generating a target driving path TL at a point where the vehicle should change direction and switch to the steering consideration mode, the driving path calculation unit 35 generates a target driving path TL as the steering consideration mode, based on the steering condition, including the path elements related to the change in direction and the target heading TD.

[0083] For example, if a change in direction of travel occurs due to forward movement during outer perimeter driving, as shown in Figure 5, the driving path calculation unit 35, in steering consideration mode, generates one or more direction change paths TLR (previously driven paths) that connect two outer perimeter paths ORL along the driving trajectory ML7, based on the steering conditions during driving related to the driving trajectory ML7. The direction change path TLR includes path elements and target headings TD corresponding to the path elements.

[0084] The travel path calculation unit 35 generates a direction change path TLR (previously traveled path) by sequentially connecting at least a portion of the aircraft's position P that was not used when generating the outer loop path ORL.

[0085] Similarly, when the direction of travel is changed by moving forward and backward during outer perimeter travel as shown in Figure 4, the travel path calculation unit 35 generates one or more direction change paths TLR along the travel trajectories ML2, ML3, and ML4.

[0086] By generating such a direction change path TLR, it is possible to generate a target travel path TL that closely resembles the travel trajectory during outer perimeter driving. As a result, automated driving can be performed accurately along the target travel path TL.

[0087] In this case, during perimeter driving, the direction of travel may be changed to avoid obstacles (OB). In actual automated driving, it is also necessary to avoid obstacles (OB), so it is appropriate to generate a direction change path (TLR) as the target driving path (TL).

[0088] For example, as shown in Figure 9, when the direction of travel is changed by repeatedly moving forward and backward while operating the steering wheel 10 to avoid an obstacle OB, the travel path calculation unit 35 generates a direction change path TLR that follows the travel trajectory of the direction change, based on the steering conditions.

[0089] With this configuration, the target driving path TL is generated as a path that avoids obstacles OB, and by performing automatic driving along the target driving path TL, automatic driving that avoids obstacles OB can be achieved.

[0090] (3) In Embodiment 1 and the other embodiments described above, the steering condition can be the operating angle of the steering handle 10 (steering angle SA) or the amount of operation of the steering handle 10 (change in steering angle SA, etc.). Furthermore, the transition to the steering consideration mode may be performed not only by considering the steering condition, but also by considering at least one of the steering condition, wheel condition, and aircraft heading condition. The wheel condition is the steering angle SA (turning angle) of the front wheels 12A or the difference in rotational speed between the left and right front wheels 12A. The aircraft heading condition is the change in the direction of travel of the aircraft 1, and may be determined from the change in the direction of travel of the aircraft 1 in the driving trajectory during manual driving, which is determined from the change in the position P of the aircraft, or it may be determined from the difference in the target heading TD in the target driving path TL. In this case, the control unit 30 is equipped with a condition acquisition unit that acquires the wheel condition and the aircraft heading condition. The steering condition acquisition unit 50 is an example of a condition acquisition unit, and the condition acquisition unit acquires at least one of the steering condition, wheel condition, and aircraft heading condition. Furthermore, if crawlers are provided as a running device instead of wheels 12, the difference in rotational speed between the left and right crawlers is obtained as part of the wheel condition. Furthermore, a steering control device such as an operating lever may be used instead of the steering wheel 10, and the operating angle and amount of the steering control device can also be used as the steering condition.

[0091] (4) In Embodiment 1 and the other embodiments described above, the previously traveled route on which the steering consideration mode is implemented may be not only route elements along the outer perimeter travel route, but also route elements along the travel route when traveling on the field FL prior to the work drive. For example, the internal round-trip route IPL or inner circumferential route IRL traveled during rice planting work in previous years may be used as the target travel route TL for the work drive to be performed this time. In that case, the steering conditions during travel on the internal round-trip route IPL or inner circumferential route IRL in previous years will be used in the steering consideration mode.

[0092] [Embodiment 2] The steering control according to Embodiment 2 will be described below with reference to Figures 2, 10, and 11.

[0093] In this embodiment, during automatic driving along a target driving path TL, the target heading TD (current target heading) of the currently driving path element LC and the target heading TD (destination target heading) of one or more path elements to be passed later (destination path elements LA) are combined to generate a combined target heading TDM. Automatic driving (automatic steering) is then controlled to align the direction of travel of the vehicle 1 (see Figure 1) with the combined target heading TDM in the currently driving path element.

[0094] For example, the driving control unit 37 combines the target direction during driving with the target direction of the next path element to be passed (adjacent to the direction of travel) (destination path element LA) to generate a combined target direction TDM, and stores it in the memory unit 40. Then, the driving control unit 37 controls automatic driving (automatic steering) so that the direction of travel of the vehicle 1 at the current driving position matches the combined target direction TDM.

[0095] With this configuration, the target direction TD (target direction of travel) of the destination path element LA is taken into account when changing the direction of travel, thus suppressing the sudden initiation of a change in direction at points where the direction of travel is to be changed.

[0096] In the above configuration, the driving control unit 37 may also be configured to generate a composite target direction (TDM) only when the lengths of the path elements before and after the change in direction of travel are less than or equal to a predetermined length.

[0097] Alternatively, the driving control unit 37 may combine the target direction during driving and the target direction of the destination using a predetermined apportionment ratio, and determine the apportionment ratio according to the distance between the current position P of the vehicle and the next path element to be traveled, which is the destination path element LA (starting point for changing direction of travel).

[0098] In this case, as shown in FIG. 10, as the current position P of the aircraft approaches the travel destination route element LA, the weight ratio of the travel destination target azimuth increases. For example, when the distance from the current position P of the aircraft to the travel destination route element LA is n1, the weight ratio of the travel target azimuth: the weight ratio of the travel destination target azimuth = 80%: 20%. When it is n2 (<n1), the weight ratio of the travel target azimuth: the weight ratio of the travel destination target azimuth = 70%: 30%. When it is n3 (<n2), the weight ratio of the travel target azimuth: the weight ratio of the travel destination target azimuth = 60%: 40%. At the end of the travel route element LC during travel, the weight ratio of the travel target azimuth: the weight ratio of the travel destination target azimuth = 50%: 50%.

[0099] With such a configuration, at a position far from the travel destination route element LA, the influence of the travel destination target azimuth becomes small. Therefore, the composite target azimuth TDM gradually approaches the travel destination target azimuth, and a steep change in the traveling direction is suppressed, and the traveling direction is appropriately changed. As a result, it is possible to suppress the aircraft 1 from deviating from the travel destination route element LA, and automatic travel along the target travel route TL is performed with high accuracy. Therefore, it is possible to suppress the aircraft 1 from bulging outward with respect to the travel destination route element LA, and to suppress contact with the ridges and obstacles OB (see FIG. 9) of the field FL.

[0100] Note that when a plurality of travel destination target azimuths are combined, the travel control unit 37 sets a lower weight ratio for the travel destination target azimuth that is farther from the travel route element LC during travel.

[0101] 〔Another Embodiment of Embodiment 2〕 (1) In Embodiment 2, as shown in FIG. 11, the travel control unit 37 may divide the travel route element LC during travel or the travel route element LC during travel and the travel destination route element LA at every predetermined distance to generate a plurality of divided route elements TLD having a predetermined length. The travel control unit 37 sets the divided target azimuth TDD of each divided route element TLD to the target azimuth TD of the travel route element LC during travel or the travel destination route element LA that is the division source.

[0102] The driving control unit 37 then synthesizes the divided target headings TDD at least in the divided path elements TLD before and after the change in direction of travel to generate a combined target heading TDM. The driving control unit 37 controls the automatic driving (automatic steering) so that the direction of travel of the vehicle 1 becomes the combined target heading TDM in the divided path elements TLD during travel.

[0103] Furthermore, as in Embodiment 2 described above, the driving control unit 37 may provide an apportionment ratio when generating the composite target direction (TDM), and may change the apportionment ratio according to the distance to the point where the direction of travel is changed.

[0104] As described above, by dividing the path elements to generate divided path element TLDs and then generating a composite target heading TDM for the divided path element TLDs, steering control can be performed closer to the point of change in direction, and a more appropriate composite target heading TDM can be generated without being excessively influenced by the destination target heading. As a result, automatic driving along the target driving path TL can be performed with greater accuracy.

[0105] (2) In the above alternative embodiment (1), the length of the dividing path element TLD may be variable. For example, the length of the dividing path element TLD may be shortened as it approaches the point where the direction of travel changes. This allows for the generation of a more accurate composite target direction (TDM) without being excessively influenced by the destination target direction.

[0106] In addition, separately or simultaneously, the length of the divided path element TLD may be increased as the difference in direction between the destination target direction of the destination path element LA and the target direction of the current path element LC increases. This allows steering control to be started earlier than the angle of change of direction, enabling more accurate automatic driving along the target driving path TL.

[0107] (3) In Embodiment 2 and the other embodiments (1) and (2) described above, the combined target direction TDM is not limited to being combined by the driving control unit 37, but may be combined by any functional block such as the driving path calculation unit 35. Similarly, the generation of the divided path element TLD is not limited to being generated by the driving control unit 37, but may be combined by any functional block such as the driving path calculation unit 35.

[0108] [Another embodiment] (1) In each embodiment, including other embodiments, some or all of the functional blocks constituting the control unit 30 are not limited to being provided on the aircraft body 1, but may also be provided on an information terminal 5 or a management computer or the like provided outside the aircraft body 1 in a state that is able to communicate with the aircraft body 1.

[0109] (2) In each embodiment, including other embodiments, the control unit 30 is not limited to being composed of the functional blocks described above, but may be composed of any functional blocks. For example, each functional block of the control unit 30 may be further subdivided, or conversely, some or all of each functional block may be combined. Also, the functions of the control unit 30 are not limited to the functional blocks described above, but may be realized by any functional block executing a method. Also, some or all of the functions of the control unit 30 may be composed of software. The program related to the software is stored in any storage device such as the memory unit 40 and executed by a processor such as the CPU of the control unit 30, or a separately provided processor. [Industrial applicability]

[0110] This invention is not limited to rice transplanters, but can be applied to the automatic driving of various work vehicles that automatically travel around work areas, including combine harvesters and tractors. [Explanation of symbols]

[0111] 1 unit 10. Steering wheel 12A front wheel 33. Aircraft position calculation unit 35. Route calculation unit 37. Driving control unit 40 Storage section 50 Steering status acquisition unit (status acquisition unit) P: Position of the aircraft SA Steering Angle (Steering Condition) TD target direction TL Target Driving Route TLR Direction Change Route

Claims

1. An automatic driving control system for a work vehicle that automatically drives along a target driving path, A machine position calculation unit that calculates the position and direction of travel of the machine body of the work vehicle, A status acquisition unit that acquires the manual driving status when the aforementioned work vehicle is manually driven, A storage unit that stores the acquired manual driving status, A driving path calculation unit that generates the aforementioned target driving path, The vehicle comprises a driving control unit that performs automatic driving control so that the work vehicle travels along the target driving path based on at least the position of the machine and the direction of travel, The target travel route generated by the travel route calculation unit includes a previously traveled travel route generated based on the travel trajectory previously driven by the work vehicle manually, The aforementioned driving control unit is an automatic driving control system that controls driving based on the position of the machine as well as the manual driving status when driving along the previously driven driving path.

2. The aforementioned manual driving conditions include at least one of the steering conditions, wheel conditions, and aircraft heading conditions during the manual driving, The automatic driving control system according to claim 1, wherein the steering condition is the operating angle of the steering handle that accepts steering operations for the work vehicle, the wheel condition is the steering angle of the front wheels of the work vehicle, and the vehicle orientation condition is the change in the direction of travel of the vehicle in the driving trajectory.

3. The automatic driving control system according to claim 1 or 2, wherein the driving control unit performs the automatic driving control that controls the driving based on the position of the machine as well as the manual driving conditions when changing the direction of travel of the machine along the previously traveled driving path.

4. The automatic driving control system according to claim 3, wherein the driving control unit performs the automatic driving control based on the position of the machine and the manual driving conditions when the angle formed by the path elements before and after the starting position of the change of direction of travel is greater than or equal to a predetermined angle.

5. The automatic driving control system according to claim 3, wherein the driving control unit performs the automatic driving control based on the position of the machine and the manual driving conditions when the angle formed by the target direction in the path elements before and after the starting position of the change of direction of travel is greater than or equal to a predetermined angle.

6. The automatic driving control system according to any one of claims 3 to 5, wherein when the driving control unit performs the automatic driving control which controls driving based on the position of the machine as well as the manual driving conditions, the automatic driving control is controlled to start from before the starting position of the change in the direction of travel along the target driving path.

7. The aforementioned manual driving conditions include at least one of the steering conditions, wheel conditions, and aircraft heading conditions during the manual driving, The automatic driving control system according to any one of claims 3 to 5, wherein the driving control unit corrects the target driving path based on at least one of the steering conditions, the wheel conditions, and the aircraft orientation conditions when performing the automatic driving control which controls driving based on the position of the aircraft in addition to the manual driving conditions.

8. The aforementioned travel path calculation unit generates a direction change path as the target travel path from the forward travel path during forward travel and the forward travel path during reverse travel, among the travel trajectories. The automatic driving control system according to any one of claims 3 to 7, wherein the driving control unit performs the automatic driving control so that the work vehicle travels along the direction change path when the direction of travel is changed.

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