Work vehicle

Abstract

To provide a work vehicle appropriately performing turning travel by detecting that inappropriate turning travel has been made.SOLUTION: A work vehicle includes an automatic work travel control part for controlling work travel by automatic travel along a straight path IPL based on a position PP of a machine body 1, and an automatic turning travel control part for controlling turning travel performed according to a predetermined prescribed procedure. When controlling the turning travel, the automatic turning travel control part calculates as a target turning circle RRC, a circle that passes through a turning start position PSR and comes into contact with the straight path IPL having traveled just before and a straight path IPL1 traveling next, calculates as a turning distance DR, a distance between a center point CRC of a target turning circle RRC and a position PP of the machine body 1 traveling, and when a difference between a radius RC of the target turning circle RRC and the turning distance DR is larger than a predetermined prescribed threshold, executes a prescribed escape control function.SELECTED DRAWING: Figure 8

Description

[Technical field]

[0001] The present invention relates to a work vehicle that performs multiple straight work drives with turning drives in between. [Background technology]

[0002] As disclosed in Patent Document 1, the rice transplanter travels back and forth along a straight path with turning travel between the two paths in the field to perform work. For turning travel, a turning path is not generated, and the end of work on the straight path is determined, and automatic turning is performed at a predetermined turning angle. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2007-244288 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, in such a rice transplanter, the turning is not performed along a turning path, but the automatic turning travel is controlled according to a predetermined turning procedure. As the turning procedure, the turning is controlled to turn at a predetermined turning angle. Therefore, if the machine body skids due to the condition of the field, etc., the planned turning may not be performed properly, and the machine may pass through an inappropriate position and end the turning at an inappropriate position.

[0005] An object of the present invention is to detect when an inappropriate turning motion has been performed and to enable the turning motion to be performed appropriately. [Means for solving the problem]

[0006] In order to achieve the above object, a work vehicle according to one embodiment of the present invention is a work vehicle that performs work travel in a field by repeating turning travel and straight travel, and includes a machine body, a machine body position calculation unit that calculates the position of the machine body, a path generation unit that generates a straight path for the straight travel, an automatic work travel control unit that controls the work travel by automatic travel along the straight path based on the position of the machine body, and a predetermined Start turning at a steering angle, return the steering angle during the turn, and head toward the next straight path to be traveled. and an automatic turning driving control unit that controls the turning driving, and when controlling the turning driving, the automatic turning driving control unit calculates a target turning circle that passes through the turning start position and is tangent to the straight line path that was previously traveled and the straight line path that will be traveled next, calculates the distance between the center point of the target turning circle and the position of the aircraft currently traveling as a turning distance, and executes a predetermined escape control function when the difference between the radius of the target turning circle and the turning distance is greater than a predetermined threshold value.

[0007] The automatic turning is performed according to a predetermined procedure, and this procedure is set so that the turning is performed appropriately from a straight path to the next straight path. Here, the vehicle may slip during the automatic turning and not turn appropriately, and even if the automatic turning is performed according to the predetermined procedure, the vehicle may not reach an appropriate position on the next straight path. In addition, since the automatic turning does not generate a driving path, it is easy to control the automatic turning, but it is not possible to check the appropriateness of the turning during the automatic turning.

[0008] According to the above configuration, during automatic turning, a target turning circle is virtually calculated, and the turning distance is compared with the radius of the target turning circle, even though the vehicle is not controlled to follow the target turning circle. When the turning distance deviates from the radius of the target turning circle by a threshold value or more, it can be determined that the vehicle has run away due to slippage or the like, and that appropriate automatic turning is not being performed. If it is determined that appropriate automatic turning is not being performed, a runaway control function is executed, and measures can be taken to perform appropriate automatic turning. As a result, it is detected that inappropriate turning is being performed, and appropriate automatic turning can be performed.

[0009] The escape control function may be a control for decelerating the aircraft at least once.

[0010] With this configuration, when it is determined that appropriate automatic turning is not being performed, measures can be taken to ensure appropriate turning while the aircraft is decelerating.

[0011] The escape control function may be a control for stopping a working unit of the machine.

[0012] With this configuration, when it is determined that the automatic turning travel is not being performed appropriately, measures can be easily taken to ensure that the turning travel is performed appropriately.

[0013] The escape control function may be a control for stopping the vehicle.

[0014] With this configuration, if it is determined that appropriate automatic turning is not being performed, the vehicle is temporarily stopped, and then measures can be easily taken to ensure that the vehicle turns appropriately.

[0015] In addition, if the vehicle is turned too wide, it may come into contact with the ridge. If it is determined that the vehicle is not turning properly, the vehicle is stopped, thereby appropriately preventing the vehicle from coming into contact with the ridge.

[0016] In addition, the difference between the radius of the target turning circle and the turning distance is calculated as an absolute value, and the automatic turning driving control unit may disable the escape control function when the turning distance is smaller than the radius of the target turning circle, even if the absolute value of the difference between the radius of the target turning circle and the turning distance is greater than the threshold value.

[0017] A situation where the turning distance is smaller than the radius of the target turning circle means that the aircraft has turned too far with a large turning angle (small turning radius) and has shifted inward with respect to the turning trajectory expected in the procedure. In such a situation, even if the aircraft is not heading to the appropriate position on the next straight path to be traveled, there is a small possibility of contacting the ridge. Also, by performing appropriate steering control in the final stage of the turn or the initial stage of traveling on a straight path, it may be possible to travel along a straight path.

[0018] Therefore, with the above configuration, even if it is determined that appropriate automatic turning is not being performed, if the aircraft body is shifted inward, the escape control function is not performed, thereby making it possible to efficiently continue automatic turning and subsequent work driving.

[0019] In addition, when controlling the turning, the automatic turning control unit may turn the vehicle body at a predetermined steering angle, and terminate the turning when the angle between a straight line parallel to the vehicle body's direction of travel and the next straight line path to be traveled becomes less than a predetermined angle.

[0020] During turning travel, when the traveling direction of the machine approaches the same direction as the traveling direction of the next straight path to be traveled, it can be determined that the machine is approaching the end position of the turn, and if the traveling direction of the machine is approximately the same as the traveling direction of the straight path, automatic work travel along the straight path can be started from there.

[0021] According to the above configuration, automatic turning travel can be easily performed, and then a smooth transition can be made to automatic work travel along a straight path. [Brief description of the drawings]

[0022] [Figure 1] FIG. 1 is a left side view illustrating the overall configuration of a rice transplanter. [Diagram 2] FIG. 1 is a plan view illustrating an example of the overall configuration of a rice transplanter. [Diagram 3] FIG. 2 is a diagram illustrating an example of a main configuration of an operation panel. [Figure 4] FIG. [Diagram 5] FIG. 11 is a diagram illustrating an example of generating a straight line path. [Figure 6] FIG. 11 is a diagram illustrating an example of a turning procedure. [Figure 7] FIG. 2 is a diagram illustrating an example of a functional configuration for controlling automatic driving. [Figure 8] 10A and 10B are diagrams illustrating an example of control in automatic turning traveling. [Figure 9] FIG. 11 is a diagram illustrating an example of a flow of automatic turning traveling. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0023] Below, a rice transplanter that travels through a field for work will be described as an example of a work vehicle.

[0024] For ease of understanding, in this embodiment, unless otherwise specified, "front" (the direction of arrow F shown in Figs. 1 and 2) means the front in the longitudinal direction (traveling direction) of the machine body, and "rear" (the direction of arrow B shown in Figs. 1 and 2) means the rear in the longitudinal direction (traveling direction) of the machine body. In addition, the left-right direction or lateral direction means the transverse direction of the machine body (machine body width direction) perpendicular to the longitudinal direction of the machine body, and "left" (the direction of arrow L shown in Fig. 2) and "right" (the direction of arrow R shown in Fig. 2) mean the leftward and rightward directions of the machine body, respectively.

[0025] [Overall structure] As shown in Figures 1 and 2, the rice transplanter is equipped with a riding type four-wheel drive machine body 1. The machine body 1 is equipped with a link mechanism 13 in the form of a parallel four-linkage connected to the rear of the machine body 1 so as to be able to rise and fall and swing, a hydraulic lifting link 13a that drives the link mechanism 13 to swing, and a seedling planting device 3 that is connected to the rear end region of the link mechanism 13 so as to be able to roll. The seedling planting device 3 is an example of a working device, and a fertilizer applicator, a chemical spraying device, etc. may be mounted as other working devices.

[0026] The machine body 1 includes wheels 12 as a mechanism for traveling, an engine 2, and a hydraulic continuously variable transmission 9 as a main transmission. The continuously variable transmission 9 is, for example, an HST (Hydro-Static Transmission), and changes the speed of the driving force output from the engine 2 by adjusting the angles of a motor swash plate and a pump swash plate. The wheels 12 include left and right front wheels 12A that can be steered, and left and right rear wheels 12B that cannot be steered. The engine 2 and the continuously variable transmission 9 are mounted on the front of the machine body 1. The power output from the engine 2 is supplied to the front wheels 12A, the rear wheels 12B, the working device, etc. via the continuously variable transmission 9, etc.

[0027] As an example, the seedling planting device 3 is configured for eight rows of planting. The seedling planting device 3 includes a seedling stand 21, eight rows of planting mechanisms 22, and five floats 15. The seedling planting device 3 can be changed to two-row, four-row, six-row, etc. planting by controlling the clutch for each row (planting clutch 23).

[0028] The seedling placing table 21 is a base on which eight mat-shaped seedlings are placed. The seedling placing table 21 moves back and forth in the left and right direction with a constant stroke corresponding to the left and right width of the mat-shaped seedlings, and each time the seedling placing table 21 reaches the left or right stroke end, each mat-shaped seedling on the seedling placing table 21 is vertically fed toward the lower end of the seedling placing table 21 at a predetermined pitch.

[0029] The eight planting mechanisms 22 are rotary type and are arranged in the left-right direction at regular intervals corresponding to the spacing between the planting rows. When the planting clutch 23 is shifted to a transmission state, the driving force is transmitted from the engine 2 to each planting mechanism 22, and the planting mechanism 22 cuts one seedling from the bottom end of each mat-like seedling placed on the seedling placement table 21 and plants it in the muddy soil after the land is leveled. In this way, the seedling planting device 3 can take out the seedlings from the mat-like seedlings placed on the seedling placement table 21 and plant them in the muddy soil of the paddy field.

[0030] The floats 15 level the field when planting seedlings. Each float 15 is provided in correspondence with two rows of planting mechanisms 22.

[0031] The machine body 1 is provided with a driving section 14 in its rear side area. The driving section 14 is provided with a steering wheel 10 for steering the front wheels, a main speed change lever 7 for adjusting the vehicle speed by changing the speed of the continuously variable transmission 9, an operation control lever 11 for controlling the raising and lowering operation of the seedling planting device 3 and the on / off operation of the planting clutch 23 (switching between a transmission state and a non-transmission state), and a driver's seat 16 for an operator (driver / worker). The steering wheel 10, the main speed change lever 7, and the operation control lever 11 are provided on the driver's panel 6 in front of the driver's seat 16. Furthermore, in front of the driving section 14, a spare seedling storage device 17A for storing spare seedlings is supported on a spare seedling support frame 17.

[0032] In addition, the spare seedling support frame 17 is provided with a positioning unit 8. The positioning unit 8 outputs positioning data for calculating the position PP (see FIG. 5) and orientation of the aircraft 1. The positioning unit 8 includes a satellite positioning module 8A that receives radio waves from satellites of the Global Navigation Satellite System (GNSS), and an inertial measurement module 8B that detects the inclination and acceleration of the three axes of the aircraft 1.

[0033] As shown in FIG. 3, the driving panel 6 is provided with a start position operation tool 18 and an end position operation tool 19. The start position operation tool 18 and the end position operation tool 19 are arranged on the left and right sides below the steering wheel 10 of the driving panel 6. The start position operation tool 18 is operated when determining a start point PA (see FIG. 5) in a teaching run described later. The end position operation tool 19 is operated when determining an end point PB (see FIG. 5) in a teaching run. The start position operation tool 18 and the end position operation tool 19 may be any operation tool that can be operated to input data, such as a push button. The arrangement of the start position operation tool 18 and the end position operation tool 19 is not limited to the arrangement shown in FIG. 3, and may be arranged in any position where the driver can operate them while driving.

[0034] [Work trip] The travel of the rice transplanter when planting rice in a farm field will be described with reference to Figs. 1 and 2 and Fig. 4.

[0035] The rice transplanter in this embodiment can selectively perform manual driving and automatic driving. In manual driving, the driver manually operates the driving operation tools such as the steering wheel 10, the main shift lever 7, and the work operation lever 11 to perform driving for work. In automatic driving, the rice transplanter drives and works under automatic control, and performs straight work driving along a straight path IPL, which will be described later, with turning driving in between. In this case, the turning driving is automatically controlled according to a predetermined procedure, without a driving path being generated.

[0036] When the rice transplanter is planting, the field is divided into an outer area OA and an inner area IA, and the transplanter travels in each area accordingly.

[0037] In the inner area IA, a plurality of straight-line paths IPL (internal round-trip paths) approximately parallel to one side of the field are generated. The straight-line paths IPL are travel paths that travel all over the entire inner area IA, and each straight-line path IPL is traveled with a turning run in between. Each time a turning run is performed, the next straight-line path IPL to be traveled is generated in sequence.

[0038] After work travel in the inner area IA is performed, work travel in the outer peripheral area OA is performed. Work travel in the outer peripheral area OA is performed by automatic travel or manual travel. When automatic work travel is performed in the outer peripheral area OA, two travel routes, an inner circular route IRL and an outer circular route ORL, are generated that travel within the outer peripheral area OA along the periphery of the field. Work travel in the entire outer peripheral area OA is performed by work travel on the inner circular route IRL and the outer circular route ORL. Note that the travel routes that travel within the outer peripheral area OA are not limited to the inner circular route IRL and the outer circular route ORL, and may be one or more travel routes.

[0039] [Automatic work driving on straight lines] Next, automatic operation traveling on a straight path will be described using FIG. 5 while referring to FIGS. 1 to 4.

[0040] First, teaching travel is performed in which manual travel is performed from one end of the internal area IA to the other end. In teaching travel, the driver operates the start position operation tool 18 at the position where the work travel will start, and registers the start point PA of the teaching travel. Then, the driver manually performs linear work travel (manual travel), and when the end position of the work travel is reached, the driver operates the end position operation tool 19 and registers the end point PB of the teaching travel. Note that the end point PB may be a position traveled in a straight line from the end position of the work travel while the seedling planting device 3 is raised.

[0041] The straight line connecting the start point PA and the end point PB is the base line RL, and at least one of the base line RL and a reference direction RD that is a direction parallel to the base line RL is registered.

[0042] Next, in order to perform a round trip work run, the driver performs a predetermined operation and turns the machine body 1 180° using the automatic turning run described below.

[0043] The end position PE of the automatic turning travel (see FIG. 6) becomes the start position PSS of straight travel, and a straight line that passes through the start position PSS and is parallel to the base line RL (in the direction of the reference direction RD) is generated as the straight path IPL to be traveled next. The straight path IPL may be defined by the start position PSS of straight travel and the travel direction (a direction parallel to the reference direction RD), but may also be defined as a set of the start position PSS and the position PP of the machine 1 to travel thereafter, or may be defined as a line segment connecting the start position PSS of straight travel and the end position of straight travel.

[0044] Then, the driver starts the automatic work traveling along the straight line path IPL. After that, the automatic work traveling along the straight line path IPL and the automatic turning traveling are repeated, and every time the automatic turning traveling is completed, the next straight line path IPL is generated, and the round trip traveling is performed throughout the entire internal area IA.

[0045] [Automatic turning] Next, automatic turning will be described using FIG. 6 while referring to FIG. 1 and FIG.

[0046] The automatic turning is started by a predetermined manual operation. The automatic turning is performed in the outer peripheral area OA, particularly in an area inside the field a predetermined distance from the ridge RW. The automatic turning is not performed along a travel route, but in a predetermined procedure determined in advance by controlling the travel devices such as the wheels 12 in a predetermined procedure.

[0047] For example, in the automatic turning travel, when the work travel on the straight path IPL ends and a predetermined manual operation is performed at the start position PSR, the front wheels 12A are first steered to a predetermined steering angle, for example, the maximum steering angle, and turning travel is performed. The travel trajectory in this travel is C1 shown in FIG. 6.

[0048] Next, when the turning angle α becomes a predetermined turning angle αC1, the steering angle is reduced. For example, when the turning angle α becomes 90° as the turning angle αC1, the steering angle is set to 0°. In other words, when the turning angle α becomes 90°, the machine body 1 runs in a direction perpendicular to the straight line path IPL, in other words, in a direction parallel to the ridge boundary line RBL. Here, the turning angle α is the angle between the line connecting the position PP of the machine body 1 during running and the midpoint CC, and the ridge boundary line RBL. The midpoint CC is the midpoint between the start position PSR of the turning of the straight line path IPL on which the work running was performed immediately before and the start position PSS of the work running on the straight line path IPL to be run next (the end position PE of the turning). In addition, the ridge boundary line RBL is a line connecting the start position PSR and the end position PE, and is a line that passes through the start position PSR and is perpendicular to the straight line path IPL or the basic straight line RL. The running trajectory in this running is C2 shown in FIG. 6.

[0049] Then, when the turning angle α reaches a predetermined turning angle αC2 (the remaining turning angle is αC3=180°-αC2), the steering angle is set to a predetermined angle, and the vehicle turns toward the end position PE of the turn (straight path IPL). At this time, automatic steering may be performed toward the end position PE of the turn. The travel path during this travel is C3 shown in FIG. 6.

[0050] [Automatic driving control] Next, a functional configuration for controlling automatic driving that performs automatic straight driving (automatic work driving) and automatic turning driving will be described using FIG. 7 with reference to FIG. 1 and FIG.

[0051] The automatic traveling is controlled by a control unit 30. The positioning unit 8, the traveling switch operation tool 25, the start position operation tool 18, the end position operation tool 19, and the wheels 12 are connected to the control unit 30 in a state in which data communication is possible.

[0052] The control unit 30 receives positioning data from the positioning unit 8. The control unit 30 also receives information on the operation of the driving switching operation device 25, the start position operation device 18, and the end position operation device 19. The driving switching operation device 25 accepts manual operation to switch between automatic driving and manual driving. The control unit 30 also controls the wheels 12 to control the driving and steering of the vehicle 1.

[0053] The control unit 30 includes a vehicle position calculation unit 32, a route generation unit 33, an automatic work driving control unit 35, and an automatic turning driving control unit 36.

[0054] The machine body position calculation section 32 intermittently or continuously calculates the position PP of the machine body 1 in the field based on the positioning data received from the positioning unit 8.

[0055] In the above teaching traveling, the path generating unit 33 calculates at least one of the base line RL and the reference direction RD. Then, the path generating unit 33 uses the calculated base line RL or the reference direction RD to generate the next straight path IPL to be traveled every time turning traveling is performed.

[0056] The rice transplanter may include an alarm unit 26 that issues a predetermined alarm. In this case, the alarm unit 26 is connected to the control unit 30, and issues the predetermined alarm under the control of the control unit 30. Then, the path generating unit 33 causes the alarm unit 26 to issue the predetermined alarm when the start point PA and the end point PB are registered in the teaching travel. For example, the alarm unit 26 is a speaker, and the path generating unit 33 causes the speaker to generate a predetermined alarm sound when the start point PA and the end point PB are registered.

[0057] Additionally, together with or instead of the notification sound, the path generating unit 33 may cause the LED serving as the notification unit 26 to emit light to notify that the start point PA and the end point PB have been registered. Furthermore, the start position operating device 18 and the end position operating device 19 may be push buttons, and an LED may be provided on the surface of each push button as the notification unit 26. The path generating unit 33 may then light up the LED of the start position operating device 18 when the start point PA is registered, and light up the LED of the end position operating device 19 when the end point PB is registered.

[0058] The automatic work traveling control unit 35 controls the automatic work traveling along the straight path IPL based on the position PP of the machine body 1 while controlling the work devices such as the seedling planting device 3.

[0059] When a predetermined manual operation is performed, the automatic turning / driving control unit 36 ​​turns the vehicle 1 in a predetermined procedure. Furthermore, the automatic turning / driving control unit 36 ​​performs processing for executing a runaway control function described later during automatic turning / driving.

[0060] Furthermore, when the automatic turning mode is entered, the automatic turning / travel control unit 36 ​​may perform control to stop the planting clutch 23 (see FIG. 2) and raise the seedling planting device 3.

[0061] [Control during automatic turning] Next, the control executed during automatic turning will be described with reference to FIG. 7 and with reference to FIG. 8 and FIG.

[0062] When automatic turning travel is started (step #1 in FIG. 9), the automatic turning travel control unit 36 ​​calculates a target turning circle RRC (step #2 in FIG. 9). The target turning circle RRC is a circle that passes through the start position PSR of automatic turning travel (turn start position) and is tangent to the straight line path IPL along which work travel was performed immediately before automatic turning travel, and the straight line path IPL1 along which the machine 1 will travel next. However, the automatic turning travel control unit 36 ​​does not control the machine 1 to travel along the target turning circle RRC during automatic turning travel.

[0063] Next, the automatic turning control unit 36 ​​calculates a center point CRC of the target turning circle RRC (step #3 in FIG. 9). For example, the automatic turning control unit 36 ​​draws a perpendicular line from the start position PSR to the straight path IPL1, and calculates the midpoint between the start position PSR and the intersection point of this perpendicular line and the straight path IPL1 as the center point CRC.

[0064] Next, the automatic turning control unit 36 ​​calculates the radius RC of the target turning circle RRC (step #4 in FIG. 9). For example, the automatic turning control unit 36 ​​calculates the distance from the intersection point between the perpendicular line and the straight path IPL1 to the start position PSR as the diameter of the target turning circle RRC, and calculates the radius RC of the target turning circle RRC from the diameter.

[0065] The automatic turning control unit 36 ​​continuously calculates the turning distance DR during automatic turning (step #5 in FIG. 9). The turning distance DR is the distance between the position PP of the machine body 1 during automatic turning and the center point CRC of the target turning circle RRC.

[0066] From the start to the end of the automatic turning, the automatic turning control unit 36 ​​continuously calculates the difference between the turning distance DR and the radius RC. Then, the automatic turning control unit 36 ​​judges whether the absolute value of the difference between the calculated turning distance DR and the radius RC is greater than a predetermined threshold value (step #6 in FIG. 9). In other words, the automatic turning control unit 36 ​​approximately calculates the deviation amount from the turning that is assumed when the turning is performed according to a predetermined procedure, based on the difference between the turning distance DR and the radius RC, and judges whether the automatic turning is being performed appropriately. While the absolute value of the difference between the turning distance DR and the radius RC is equal to or less than the threshold value (step #6 No in FIG. 9), the automatic turning control unit 36 ​​continues to control the automatic turning.

[0067] If the absolute value of the difference between the turning distance DR and the radius RC becomes greater than the threshold value (step #6 Yes in FIG. 9), the automatic turning control unit 36 ​​determines that automatic turning is not being performed appropriately and executes the escape control function to stop the vehicle 1 (step #7 in FIG. 9).

[0068] This makes it possible to easily determine whether or not automatic turning is being performed appropriately by virtually regarding the target turning circle RRC as a travel trajectory for automatic turning, based on the deviation between the target turning circle RRC and the vehicle 1. When it is determined that automatic turning is not being performed appropriately, the vehicle 1 is stopped, and thereafter, turning can be performed manually or the steering angle during automatic turning can be adjusted, thereby allowing appropriate turning to be continued.

[0069] In addition, in the case where the notification unit 26 is provided, the automatic turning driving control unit 36 ​​may cause the notification unit 26 to make a predetermined notification when executing the escape control function.

[0070] [Another embodiment] (1) In the above embodiment, the vehicle 1 is stopped as the escape control function, but the escape control function is not limited to this control. For example, the automatic turning travel control unit 36 ​​may stop at least one of the engine 2, the planting mechanism 22 (corresponding to the working unit) and the seedling planting device 3 as the escape control function. This makes it easy to respond when resuming turning travel.

[0071] Furthermore, the automatic turning control unit 36 ​​may decelerate (reduce the vehicle speed) the vehicle 1 at least once as a runaway control function. This also allows the vehicle 1 to take necessary measures such as changing the turning angle while the vehicle speed is being reduced, and then perform appropriate turning.

[0072] In addition, deceleration may be performed in stages while observing the turning situation. For example, if the deviation is still large after the first deceleration, a second deceleration with a larger deceleration amount may be performed, and the turning may be adjusted by deceleration multiple times.

[0073] (2) In each of the above embodiments, even if the absolute value of the difference between the turning distance DR and the radius RC is greater than a threshold value, if the turning distance DR is smaller than the radius RC, the automatic turning control unit 36 ​​may disable the escape control function.

[0074] When the turning distance DR is smaller than the radius RC, the machine body 1 is not turning in a direction that causes it to bulge toward the ridge RW, but is turning toward the center point CRC at a small turning angle α. In such a situation, the machine body 1 is unlikely to come into contact with the ridge RW. Therefore, when the turning distance DR is smaller than the radius RC, even if the escape control function of the automatic turning control unit 36 ​​is disabled, the possibility of problems occurring in turning is relatively small. By performing such control, the continuity of turning is maintained.

[0075] (3) In each of the above embodiments, the automatic turning travel is not limited to the procedure described with reference to Fig. 6, and may be performed according to any predetermined procedure. For example, the automatic turning travel control unit 36 ​​may fix the steering angle and perform automatic turning travel at one predetermined steering angle. In this case, the automatic turning travel control unit 36 ​​may also automatically steer in the final stage of turning travel based on the start position PSS of the automatic work travel of the next straight line path IPL and the position PP of the machine body 1.

[0076] Furthermore, the automatic turning is not limited to a configuration in which the automatic turning is performed up to the start position PSS of the next straight path IPL, and the automatic turning may be terminated when the traveling direction of the machine body 1 approaches the traveling direction of the next straight path IPL by a predetermined degree. For example, the automatic turning control unit 36 ​​may terminate the automatic turning when the angle between a straight line parallel to the traveling direction of the machine body 1 and the next straight path IPL becomes equal to or smaller than a predetermined angle.

[0077] After the automatic turning travel is completed, the automatic work travel control unit 35 performs steering control of the machine body 1 so that it follows the next straight line path IPL.

[0078] (4) In each of the above embodiments, when the automatic driving starts or during automatic driving, if there is an obstacle ahead in the direction of travel or around the machine body 1, problems may occur with driving or work. For this reason, the rice transplanter of this embodiment may be equipped with a sonar sensor as an example of an obstacle detection device 28 (see FIG. 7) that detects obstacles around the machine body 1. The sonar sensor detects objects within a predetermined distance range as obstacles. Detection of obstacles is basically performed during automatic driving, but it may also be configured to detect obstacles during manual driving.

[0079] When the sonar sensor detects an obstacle, the travel prohibition control unit 38 stops the machine 1. This makes it possible to prevent the machine 1 from coming into contact with the obstacle. Note that such control may be performed not only during automatic work travel along the straight path IPL, but also during automatic turning travel, and may also be performed during manual travel.

[0080] (5) In each of the above embodiments, the rice transplanter is not limited to being driven by the engine 2, and may be driven by any prime mover.

[0081] (6) In each of the above embodiments, the traveling device is not limited to the wheels 12, and may be any traveling device such as a crawler.

[0082] (7) In each of the above embodiments, the control unit 30 is not limited to being composed of the above-mentioned functional blocks, and 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 the functional blocks may be combined. In addition, the functions of the control unit 30 are not limited to the above-mentioned functional blocks, and may be realized by a method executed by any functional block. In addition, some or all of the functions of the control unit 30 may be composed of software. A program related to the software is stored in any storage device and executed by a processor such as a CPU included in the control unit 30 or a processor provided separately.

[0083] The rice transplanter may also include an information terminal 5. The information terminal 5 has a touch panel (monitor screen) that displays various information and warnings and notifies (outputs) the operator, and receives input of various information. The information terminal 5 is detachably provided in the driver's section 14 in a manner that allows the driver seated in the driver's seat 16 to view and operate it. The control unit 30 may be configured to be mounted on the machine body 1, but some or all of the functions of the control unit 30 may be provided in the information terminal 5. [Industrial Applicability]

[0084] The present invention can be applied to rice transplanters, agricultural work vehicles that travel in fields while making turns, and various other work vehicles that travel in work areas while making turns. [Explanation of symbols]

[0085] 1 Aircraft 22 Planting mechanism (working part) 32 Aircraft position calculation unit 33 Route Generation Unit 35 Automatic work driving control unit 36 Automatic turning control unit CRC center point DR Turning Distance DRP ridge distance IPL Straight Path IPL1 Straight path PP position PSR start position (turn start position) RC radius RRC target turning circle

Claims

1. A work vehicle that performs work travel in a field by repeating turning and straight travel, The aircraft and an aircraft position calculation unit that calculates a position of the aircraft; A route generating unit that generates a straight line route for the straight traveling; an automatic work travel control unit that controls the work travel by automatic travel along the linear path based on the position of the machine body; an automatic turning control unit that starts turning at a predetermined steering angle, returns the steering angle during the turning, and controls the turning without a target turning path toward the straight path to be traveled next; When controlling the turning travel, the automatic turning travel control unit calculates a target turning circle as a circle that passes through the turning start position and is tangent to the straight path previously traveled and the straight path to be traveled next, calculates the distance between the center point of the target turning circle and the position of the vehicle currently traveling as a turning distance, and executes a predetermined escape control function when the difference between the radius of the target turning circle and the turning distance is greater than a predetermined threshold value.

2. The work vehicle according to claim 1 , wherein the escape control function is a control for decelerating the vehicle at least once.

3. The work vehicle according to claim 1 or 2, wherein the escape control function is a control for stopping a working unit of the vehicle.

4. The work vehicle according to claim 1 or 2, wherein the escape control function is a control for stopping the vehicle.

5. A difference between the radius of the target turning circle and the turning distance is calculated as an absolute value, The work vehicle of claim 1 or 2, wherein the automatic turning control unit disables the escape control function when the turning distance is smaller than the radius of the target turning circle, even if the absolute value of the difference between the radius of the target turning circle and the turning distance is greater than the threshold value.

6. The work vehicle according to claim 1 or 2, wherein the automatic turning control unit, when controlling the turning, terminates the turning when an angle between a straight line parallel to the traveling direction of the vehicle and the next straight line path to be traveled becomes equal to or smaller than a predetermined angle.

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