Autonomous Driving System

Abstract

An autonomous driving system that allows a work vehicle to autonomously travel in a farm field has a configuration that can widen the area in which the work vehicle works along a straight path. [Solution] The autonomous driving system includes a reverse control unit. The reverse control unit stops a work vehicle (rice transplanter 1) traveling toward the edge of a field, and then reverses the work vehicle. The autonomous driving system autonomously stops the work vehicle while it is reversing using the reverse control unit.

Description

[Technical Field]

[0001] The present invention primarily relates to an autonomous driving system that allows a work vehicle to travel autonomously. [Background technology]

[0002] Patent Document 1 discloses a configuration in which a travel route is created that includes straight paths laid out in a field and turning paths that connect the straight paths, and a work vehicle is made to travel autonomously along this travel route. Furthermore, this work vehicle performs work on the field while traveling along the straight paths, and does not perform work on the field while traveling along the turning paths. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2018-117560 Summary of the Invention [Problem to be solved by the invention]

[0004] However, when starting to turn a work vehicle at a predetermined position as in Patent Document 1, the turning start position is set to a position with a margin of error to ensure that the work vehicle turns reliably and appropriately, which results in a narrow area of ​​the field where the work vehicle can work along a straight path.

[0005] The present invention has been made in consideration of the above circumstances, and its main purpose is to provide a configuration in an autonomous driving system that allows a work vehicle to drive autonomously in a field, which makes it possible to expand the area in which the work vehicle works along a straight path. [Means for solving the problem]

[0006] An autonomous driving system according to one aspect of the present invention includes a reverse control unit. The reverse control unit stops a work vehicle traveling toward the edge of a field and then reverses the work vehicle. The autonomous driving system autonomously stops the work vehicle while it is traveling in reverse by using the reverse control unit. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 1 is a side view of a rice transplanter that is a target of autonomous driving in an autonomous driving system according to a first embodiment. [Figure 2] Plan view of the rice transplanter. [Figure 3] FIG. 1 is a block diagram of a rice transplanter and a wireless communication terminal. [Figure 4] FIG. 4 is a diagram showing a travel route created by a route creation unit. [Figure 5] 10 is a flowchart showing a process of turning the rice transplanter near the edge of a field. [Figure 6] A diagram showing the rice transplanter turning near the edge of the field. [Figure 7] FIG. 10 is a diagram showing processing performed in another turning process. [Figure 8] FIG. 10 is a block diagram of a rice transplanter and a wireless communication terminal according to a second embodiment. [Figure 9] 10 is a flowchart showing a process for turning the rice transplanter near the edge of a field in the second embodiment. [Figure 10] FIG. 10 is a diagram showing the rice transplanter turning near the edge of the field in the second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0008] Next, an embodiment of the present invention will be described with reference to the drawings. Fig. 1 is a side view of a rice transplanter 1 used in an autonomous driving system 100 according to a first embodiment of the present invention. Fig. 2 is a plan view of the rice transplanter 1. Fig. 3 is a block diagram of the rice transplanter 1 and a wireless communication terminal 7.

[0009] The autonomous driving system 100 of this embodiment uses a rice transplanter 1 as a work vehicle that works in a farm field, and an operator gives instructions using a wireless communication terminal 7 or the like, causing the rice transplanter 1 to autonomously travel and perform work (agricultural work such as planting seedlings). Note that instructions for autonomous travel may be given by operating an operating device provided on a work vehicle such as the rice transplanter 1, rather than by using the wireless communication terminal 7. Furthermore, the work vehicle in the present invention is not limited to the rice transplanter 1, and for example, a seed drill, a tractor, a combine harvester, etc. may also be used.

[0010] Autonomous driving means that the control unit provided in the rice transplanter 1 controls devices related to driving, and at least steering is performed autonomously to follow a predetermined route. In addition to steering, the rice transplanter may also be configured to perform autonomous control of vehicle speed or work by a work machine. Autonomous driving includes cases where a person is riding on the rice transplanter 1 and cases where a person is not riding on the rice transplanter 1.

[0011] 1 and 2, the rice transplanter 1 includes a vehicle body 11, front wheels 12, rear wheels 13, and a planting unit (working unit) 14. The front wheels 12 and rear wheels 13 are provided in pairs on the left and right sides of the vehicle body 11.

[0012] The vehicle body 11 includes a hood 21. The hood 21 is provided at the front of the vehicle body 11. An engine 22 is provided inside the hood 21.

[0013] The power generated by the engine 22 is transmitted to the front wheels 12 and rear wheels 13 via a transmission case 23. This power is also transmitted to the planting section 14 via the transmission case 23 and a PTO shaft 24 disposed at the rear of the vehicle body section 11.

[0014] The vehicle body 11 further includes a driver's seat 25 and a plurality of operating members. An operator can sit in the driver's seat 25. The driver's seat 25 is disposed between the front wheels 12 and the rear wheels 13 in the longitudinal direction of the vehicle body 11. The plurality of operating members include a steering handle 26, a speed change operation pedal 27, a main speed change lever 28, and a planting clutch lever 29.

[0015] The rice transplanter 1 can be steered by operating the steering handle 26. The traveling speed (vehicle speed) of the rice transplanter 1 can be adjusted by operating the speed change pedal 27. The main speed change lever 28 is configured to be able to select, for example, "forward," "reverse," "stop," etc. When the main speed change lever 28 is operated to the "forward" position, power is transmitted to rotate the rear wheels 13 in a direction that moves the rice transplanter 1 forward. On the other hand, when the main speed change lever 28 is operated to the "reverse" position, power is transmitted to rotate the rear wheels 13 in a direction that moves the rice transplanter 1 backward. When the main speed change lever 28 is operated to the "stop" position, power transmission to the front wheels 12 and the rear wheels 13 is cut off. Note that "forward" may be divided into "low speed" for traveling within a field and "high speed" for traveling outside the field. By operating the planting clutch lever 29, it is possible to switch between a transmission state in which the planting clutch transmits power to the PTO shaft 24 (i.e., the planting unit 14) and a disconnection state in which the planting clutch does not transmit power to the PTO shaft 24 (i.e., the planting unit 14).

[0016] The planting unit 14 is located behind the vehicle body 11. The planting unit 14 is connected to the vehicle body 11 via a lifting link mechanism 31. The lifting link mechanism 31 is composed of a parallel link including a top link 31a and a lower link 31b.

[0017] In the lifting link mechanism 31, a lifting cylinder 32 of a lifting device is connected to the lower link 31b. The lifting device can raise and lower the planting unit 14 up and down relative to the vehicle body 11 by extending and retracting the lifting cylinder 32. In this embodiment, the lifting cylinder 32 is a hydraulic cylinder, but it may also be an electric cylinder. The lifting device may also raise and lower the planting unit 14 using an actuator other than a cylinder.

[0018] The planting section 14 includes a planting input case section 33, a plurality of planting units 34, a seedling carrier 35, a plurality of floats 36, and a spare seedling carrier 37. The planting section 14 sequentially supplies seedlings from the seedling carrier 35 to each planting unit 34, allowing for continuous planting of seedlings.

[0019] Each planting unit 34 has a planting transmission case 41 and a rotating case 42. Power is transmitted to the planting transmission case 41 via the PTO shaft 24 and the planting input case 33.

[0020] The rotating case 42 is rotatably attached to the planting transmission case 41. The rotating case 42 is arranged on both sides in the vehicle width direction of the planting transmission case 41. Two planting claws 43 are attached to one side of each rotating case 42.

[0021] The two planting claws 43 are aligned in the traveling direction of the rice transplanter 1. The two planting claws 43 are displaced with the rotation of the rotating case part 42. As the two planting claws 43 are displaced, one row of seedlings is planted.

[0022] The seedling carrier 35 is located above and in front of the planting units 34. A seedling mat can be placed on the seedling carrier 35. The seedling carrier 35 is configured to supply the seedlings in the seedling mat placed on the seedling carrier 35 to each planting unit 34.

[0023] Specifically, the seedling carrier 35 is configured to be able to move laterally (slide laterally) back and forth in the width direction of the vehicle. Also, the seedling carrier 35 is configured to be able to intermittently transport the seedling mat vertically downward at the end of the reciprocating movement of the seedling carrier 35.

[0024] The float 36 is provided swingably at the bottom of the planting unit 14. The bottom surface of the float 36 can be brought into contact with the surface of the field in order to stabilize the planting posture of the planting unit 14 relative to the surface of the field.

[0025] A pair of spare seedling trays 37 are provided on the left and right sides of the vehicle body 11. The spare seedling trays 37 are arranged on the outer side of the hood 21 in the vehicle width direction. The spare seedling trays 37 can carry seedling boxes containing spare mat seedlings.

[0026] The upper parts of the pair of left and right spare seedling trays 37 are connected by a connecting frame 15 that extends vertically and in the vehicle width direction. A housing 16 is provided in the center of the connecting frame 15 in the vehicle width direction. Inside the housing 16, a positioning antenna 61, an inertial measurement unit 62, and a communication antenna 63 are provided.

[0027] The positioning antenna 61 can receive radio waves from positioning satellites that make up the Global Navigation Satellite System (GNSS). Based on these radio waves, known positioning calculations are performed, allowing the position of the rice transplanter 1 to be obtained.

[0028] The inertial measurement device 62 has three gyro sensors (angular velocity sensors) and three acceleration sensors. The angular velocity and acceleration of the rice transplanter 1 detected by the inertial measurement device 62 are used as auxiliary sensors, thereby improving the accuracy of the positioning results of the rice transplanter 1.

[0029] The communication antenna 63 is an antenna for wireless communication with the wireless communication terminal 7 shown in Fig. 3. The rice transplanter 1 is also provided with a mobile communication antenna (not shown) for communication using a mobile phone line and the Internet.

[0030] As shown in FIG. 3, the control unit 50 includes a calculation device, a storage device, an input / output unit, and the like (not shown). The storage device stores various programs, data, and the like. The calculation device can read and execute various programs from the storage device. Through cooperation between the above hardware and software, the control unit 50 can operate as a forward control unit 51, a reverse control unit 52, a turning control unit 53, and a work implement control unit 54. The control unit 50 may be a single piece of hardware, or multiple pieces of hardware that can communicate with each other. In addition to the inertial measurement unit 62, the control unit 50 is also connected to a position acquisition unit 64, a communication processing unit 65, a vehicle speed sensor 66, a steering angle sensor 67, and a planting clutch sensor 68.

[0031] The position acquisition unit 64 is electrically connected to the positioning antenna 61. The position acquisition unit 64 acquires the position of the rice transplanter 1 as, for example, latitude and longitude information from the positioning signal received by the positioning antenna 61. The position acquisition unit 64 receives the positioning signal from a reference station (not shown) using an appropriate method and then performs positioning using the well-known GNSS-RTK method. However, instead of this, positioning using, for example, differential GNSS, or standalone positioning, etc. may be performed. Alternatively, position acquisition based on the radio wave strength of a wireless LAN or the like, or position acquisition using inertial navigation, etc. may be performed.

[0032] The communication processing unit 65 is electrically connected to the communication antenna 63. The communication processing unit 65 can transmit and receive data to and from the wireless communication terminal 7 by performing modulation processing or demodulation processing using an appropriate method.

[0033] The vehicle speed sensor 66 can detect the vehicle speed of the rice transplanter 1. The vehicle speed sensor 66 is provided at an appropriate position on the rice transplanter 1, for example, on the axle of the front wheels 12. In this case, the vehicle speed sensor 66 generates pulses according to the rotation of the axle of the front wheels 12. The data of the detection results obtained by the vehicle speed sensor 66 is output to the control unit 50.

[0034] The steering angle sensor 67 can detect the steering angle of the front wheels 12. The steering angle sensor 67 is provided at an appropriate position on the rice transplanter 1, for example, on a kingpin (not shown) provided on the front wheels 12. The steering angle sensor 67 may also be provided on the steering handle 26. Data on the detection results obtained by the steering angle sensor 67 is output to the control unit 50.

[0035] The planting clutch sensor 68 is a sensor that detects the position of the planting clutch lever 29. The detection result of the planting clutch sensor 68 is output to the control unit 50. The control unit 50 can determine whether planting is being performed based on the detection result of the planting clutch sensor 68. The detection result data obtained by the planting clutch sensor 68 is output to the control unit 50. Note that the planting clutch sensor 68 may also determine whether planting is being performed based on the state of another component (for example, whether the PTO shaft 24 downstream of the planting clutch is rotating) rather than the planting clutch lever 29.

[0036] The forward control unit 51, the reverse control unit 52, and the turning control unit 53 can perform control related to the traveling of the rice transplanter 1 (for example, vehicle speed control and steering control). The forward control unit 51 performs control related to the forward traveling of the rice transplanter 1. The reverse control unit 52 performs control related to the reverse traveling of the rice transplanter 1. The turning control unit 53 performs control related to the turning of the rice transplanter 1. In the following explanation, the forward control unit 51, the reverse control unit 52, and the turning control unit 53 may be collectively referred to as the "traveling control unit." The traveling control unit performs control related to the autonomous traveling of the rice transplanter 1. The traveling control unit can also control the traveling of the rice transplanter 1 in response to the operation of the operator. Furthermore, the traveling control unit can, for example, perform steering autonomously and also perform control to change the vehicle speed in response to the operation of the operator.

[0037] When autonomously changing the vehicle speed, the travel control unit controls the current vehicle speed obtained based on the detection result of the vehicle speed sensor 66 to approach the target vehicle speed. This control is realized by changing at least one of the gear ratio of the transmission in the transmission case 23 and the rotation speed of the engine 22. Note that this vehicle speed control also includes control to set the vehicle speed to zero so that the rice transplanter 1 stops.

[0038] When steering autonomously, the travel control unit controls the current steering angle obtained from the detection results of the steering angle sensor 67 to approach the target steering angle. This control is realized, for example, by driving a steering actuator provided on the rotation shaft of the steering wheel 26. Regarding steering control, the travel control unit may directly adjust the steering angle of the front wheels 12 of the rice transplanter 1 instead of the rotation angle of the steering wheel 26.

[0039] The work machine control unit 54 can control the operation of the planting unit 14 (lifting and lowering operation, planting work, etc.) based on predetermined conditions.

[0040] The wireless communication terminal 7 is a tablet terminal and includes a communication antenna 71, a communication processing unit 72, a display unit 73, an operation unit 74, and a control unit 80. The wireless communication terminal 7 is not limited to a tablet terminal, and may be a smartphone or a laptop. The wireless communication terminal 7 performs various processes related to the autonomous traveling of the rice transplanter 1, as described below, but at least some of these processes can also be performed by the control unit 50 of the rice transplanter 1. Conversely, at least some of the various processes related to the autonomous traveling performed by the control unit 50 of the rice transplanter 1 can also be performed by the wireless communication terminal 7.

[0041] The communication antenna 71 is an antenna for short-range communication for wireless communication with the rice transplanter 1. The communication processing unit 72 is electrically connected to the communication antenna 71. The communication processing unit 72 can transmit and receive data to and from the rice transplanter 1 by performing modulation or demodulation processing using an appropriate method. As described above, the rice transplanter 1 can be connected to a mobile phone line, and therefore the wireless communication terminal 7 can be connected to the mobile phone line via the rice transplanter 1. Therefore, for example, part of the information stored in the control unit 50 or the control unit 80 can also be stored in an external server. Note that the antenna for mobile communication may be provided in the wireless communication terminal 7 rather than in the rice transplanter 1.

[0042] The display unit 73 is a liquid crystal display, an organic EL display, or the like, and is configured to be able to display images. The display unit 73 can display, for example, information regarding autonomous driving, information regarding the settings of the rice transplanter 1, detection results of various sensors, and warning information. The operation unit 74 includes a touch panel and hardware keys. The touch panel is placed on top of the display unit 73, and is capable of detecting operations by the operator's fingers, etc. The hardware keys are placed on the side of the housing of the wireless communication terminal 7 or around the display unit 73, etc., and can be operated by the operator pressing them. Note that the wireless communication terminal 7 may be configured to have only either a touch panel or hardware keys.

[0043] The control unit 80 includes an arithmetic unit, a storage device, an input / output unit, and the like, which are not shown. The storage device stores various programs, data, and the like. The arithmetic unit can read and execute various programs from the storage device. The above hardware and software work together to allow the control unit 80 to operate as a storage unit 81 and a path creation unit 82. The processing performed by each unit of the control unit 80 will be described later.

[0044] Next, with reference to FIG. 4, a description will be given of a field and a travel route created in the field. The field includes a work area and a headland area. The work area is located in the center of the field and is an area for carrying out work. The headland area is located outside the work area and is an area used for carrying out work appropriately in the work area. For example, the headland area is used to move the rice transplanter 1 that has entered the field to a start position for work in the work area. Furthermore, the headland area is also used as an area for turning the rice transplanter 1. Note that a travel route may be created without distinguishing between the work area and the headland area.

[0045] In this embodiment, a travel path 91 shown in FIG. 4 is created in advance as a travel path for autonomously traveling the rice transplanter 1. The travel path 91 is created by the path creation unit 82. As shown in FIG. 4, the travel path 91 is made up of a plurality of straight path paths 91a. The travel path 91 is a path intended for autonomous traveling only on straight portions. In this embodiment, turning is performed at a position according to the operation of the operator, as will be described later, so a turning path is not created in advance. However, the path creation unit 82 may create a turning path in advance. In this case, the travel path includes a straight path and a turning path connecting the straight path paths.

[0046] The straight path 91a is a straight path that is parallel to, for example, one side (e.g., a short side) of the outline of the field or work area. The length of the straight path 91a is not particularly limited. For example, the path creation unit 82 may create a straight path 91a that fits within the above-mentioned work area, or may create a straight path 91a that extends outside the work area or outside the field. The placement interval of the straight paths 91a is determined based on, for example, the work width, the overlap length (the length indicating the degree to which adjacent work areas overlap in the vehicle width direction), and the work interval (the length indicating the amount of space between adjacent work areas in the vehicle width direction).

[0047] Next, the flow of operations when turning the rice transplanter 1 near the edge of the field (the edge of the ridge) in this embodiment will be described with reference to Figures 5 to 7. Note that the flowcharts shown in the first and second embodiments are examples, and the order of the processes may be changed, or multiple processes may be performed in parallel. Also, some processes may be omitted, or other processes may be added.

[0048] As described above, in Patent Document 1, the work vehicle autonomously starts turning at a predetermined turning start position. To ensure reliable and appropriate turning, the turning start position is set to a position with a sufficient margin. As a result, the area of ​​the field in which the work vehicle works along a linear path is narrowed. Therefore, if work is not performed in the headland area, the work area is narrowed, and the field cannot be used effectively. Furthermore, even when work is performed in the headland area, the headland area may become wider, resulting in an increase in the number of times the rice transplanter 1 must circle the headland area. Taking the above into consideration, in this embodiment, the rice transplanter 1 can work up to the edge of the field and turn near the edge of the field, thereby widening the area in which the rice transplanter 1 works along a linear path. As a result, the number of times the rice transplanter 1 must circle the headland area can be reduced (e.g., from two times to one time). Specific processing is described below.

[0049] The operator stops the rice transplanter 1 at a predetermined position on the linear path 91a, and then performs a predetermined operation on, for example, the wireless communication terminal 7. As a result, the forward movement control unit 51 starts the autonomous traveling of the rice transplanter 1 along the linear path 91a (S101, forward movement step in FIG. 6). During the forward movement step, the planting unit 14 performs work and the rice transplanter 1 is steered autonomously. During the forward movement step, the vehicle speed may be changed autonomously, or the vehicle speed may be changed by the operator (specifically, by operating the gearshift pedal 27) by operating the gearshift pedal 27. Note that a gearshift lever may be provided instead of the gearshift pedal 27, and the operator may change the vehicle speed by operating the gearshift lever.

[0050] As the rice transplanter 1 autonomously travels along the linear path 91a, it travels toward the edge of the field. When the rice transplanter 1 reaches the vicinity of the field edge, the operator performs a stop operation (e.g., by releasing the foot from the gear change pedal 27) to stop the rice transplanter 1. Note that in the forward movement process of FIG. 6, "Stop: Operator Operation" is described. This means that the process of stopping the rice transplanter 1 near the field edge is not autonomous but is performed by the operator (in other words, the operator determines the timing of the stop). Therefore, stopping in other situations (e.g., when an abnormality occurs) may be performed autonomously. By having the operator perform the stop operation of the rice transplanter 1 near the field edge, the rice transplanter 1 can be brought closer to the field edge compared to when the rice transplanter 1 is stopped autonomously. This allows for a wider area in which work can be performed along the linear path 91a. The operator also performs an operation to stop work, i.e., an operation to switch the position of the planting clutch lever 29, before and after stopping the rice transplanter 1. The planting clutch may be switched from the engaged state to the disengaged state without the operator operating the planting clutch lever 29. Specifically, the control unit 50 switches the planting clutch from the engaged state to the disengaged state when it detects that the rice transplanter 1 has stopped or has switched from forward to reverse. The fact that the rice transplanter 1 has stopped or switched from forward to reverse can be detected, for example, based on the detection value of the vehicle speed sensor 66 or the position of the main shift lever 28.

[0051] Next, the operator performs a reverse operation to move the rice transplanter 1 backward, that is, sets the main shift lever 28 to the "reverse" position and depresses the speed change pedal 27. When the reverse control unit 52 determines that the operator has performed a reverse operation (S102), it moves the rice transplanter 1 backward (S103, reverse process). During the reverse process, no work is performed by the planting unit 14. Furthermore, during the reverse process, steering may be performed autonomously or by the operator. Furthermore, during the reverse process, the vehicle speed may be changed autonomously or by the operator's operation. Note that the description "Stop: Operator Operation" in the reverse process in Figure 6 has the same meaning as in the forward process.

[0052] The operator reverses the rice transplanter 1 to a position where it can turn without contacting the edge of the field, and then performs the above-mentioned stopping operation to stop the rice transplanter 1. As will be described later, the rice transplanter 1 can also be stopped autonomously during the reverse process. Next, the operator performs a forward operation to move the rice transplanter 1 forward, that is, by setting the main shift lever 28 to the "forward" position and stepping on the shift operation pedal 27. When the turning control unit 53 determines that the operator has performed a forward operation (S104), it causes the rice transplanter 1 to turn autonomously while moving forward (S105, turning process). At this time, in this embodiment, turning by autonomous traveling is started without the operator having to operate the wireless communication terminal 7. This reduces the effort required for the operator to give instructions.

[0053] More specifically, the turning control unit 53 starts turning by autonomous driving when multiple conditions (turning start conditions) for starting turning by autonomous driving are met. One of the turning start conditions is that the operator performs a forward operation. Other conditions may be added, for example, that the position of the rice transplanter 1 is close to the edge of the field, or that the rice transplanter 1 has stopped after moving backward. Adding these conditions can prevent the rice transplanter 1 from turning in the center of the field, etc. Whether the rice transplanter 1 is located near the edge of the field can be determined by comparing the position of the rice transplanter 1 with the position of the field.

[0054] During the turning process, no work is performed by the planting unit 14. Furthermore, during the turning process, steering is performed autonomously. Furthermore, during the turning process, the vehicle speed may be changed autonomously or may be changed by the operator.

[0055] In this embodiment, the rice transplanter 1 autonomously turns to the next pre-specified straight path 91a as follows: Whether the rice transplanter 1 turns to reach the adjacent straight path 91a or to reach the further distant straight path 91a is specified in advance.

[0056] The turning control unit 53 of this embodiment first turns the rice transplanter 1 until the orientation of the rice transplanter 1 reaches a predetermined angle. In the example shown in FIG. 6, the rice transplanter 1 is turned until the orientation of the rice transplanter 1 is perpendicular to the linear path 91a (in other words, the rice transplanter 1 is turned 90°). Next, the turning control unit 53 causes the rice transplanter 1 to travel autonomously with the next linear path 91a (more specifically, a point on the linear path 91a) as its destination. This allows the rice transplanter 1 to turn to the next linear path 91a.

[0057] Note that the rice transplanter 1 may be rotated to the next linear path 91a using another method. Specifically, as shown in FIG. 7, a first rotation path 91b is created when the path is created in advance. This first rotation path 91b is created at a position with ample clearance to ensure that the rice transplanter 1 can rotate reliably and appropriately. Then, in step S105, the rotation control unit 53 sets a second rotation path 91c by moving the first rotation path 91b based on the current position of the rice transplanter 1. Normally, the second rotation path 91c is closer to the edge of the field than the first rotation path 91b. Then, the rotation control unit 53 autonomously drives the rice transplanter 1 along this second rotation path 91c. This allows the rice transplanter 1 to rotate to the next linear path 91a.

[0058] After reaching the next straight path 91a, the forward control unit 51 again causes the rice transplanter 1 to autonomously travel along the straight path 91a (S101, forward step). Thereafter, the same process is performed until the rice transplanter 1 reaches its destination. By turning the rice transplanter 1 using the method of this embodiment, the rice transplanter 1 can work up to the edge of the field, thereby widening the area in which work is performed along the straight path. As a result, for example, the number of times the rice transplanter 1 goes around the headland area can be reduced (for example, from two times to one time).

[0059] Next, an autonomous driving system 100 according to a second embodiment will be described with reference to Figures 8 to 10. In the description of the second embodiment, components that are the same as or similar to those in the first embodiment described above are denoted by the same reference numerals in the drawings, and descriptions thereof may be omitted.

[0060] As shown in FIG. 8, the control unit 80 of the second embodiment can further operate as a calculation unit 83 and a notification unit 84 through cooperation between the above hardware and software.

[0061] FIG. 9 shows the processing related to autonomous driving (particularly turning near the edge of a field) performed by the autonomous driving system 100 in the second embodiment. Steps S201, S203, and S204 in the flowchart shown in FIG. 9 are the same processing as steps S101, S102, and S103 in FIG. 5, and therefore description thereof will be omitted. However, in the second embodiment, the calculation unit 83 measures a first distance during the forward movement process (S202). The first distance is a length that serves as an index of how close the rice transplanter 1 can be brought to the edge of the field. Specifically, the first distance is the distance traveled by the rice transplanter 1 while the measurement conditions are satisfied. The first distance is indicated by L1 in FIG. 10.

[0062] The period during which the measurement conditions are satisfied refers to the period from when the measurement start condition is satisfied until the measurement end condition is satisfied. Examples of the measurement start condition include when the distance from the rice transplanter 1 to the edge of the field is equal to or less than a threshold, or when the operator switches from autonomous driving to manual driving. Examples of the measurement end condition include when the rice transplanter 1 stops, when the rice transplanter 1 starts moving backward, when the planting clutch lever 29 is switched from the working position to the non-working position, or when the planting unit 14 rises. Note that it may be possible to set which of these measurement start conditions and measurement end conditions is applied.

[0063] The calculation unit 83 calculates the first distance, which is the distance traveled by the rice transplanter while the measurement condition is satisfied, and then calculates the notification distance (S102). The notification distance is a distance used to notify the operator that the turning start position is approaching during the reverse movement process. For example, by using the first distance and the position of the field, it is possible to determine how close the rice transplanter 1 can be to the edge of the field without contacting the edge. In addition, the amount of space required in front of the rice transplanter 1 when turning can be determined from information about the body of the rice transplanter 1. Therefore, by using the first distance, it is possible to determine the minimum distance required to turn the rice transplanter 1 close to the edge of the field without contacting the edge. The minimum distance may be used as the notification distance, or a value slightly larger or smaller than the minimum distance may be used as the notification distance.

[0064] During the backward movement process, the notification unit 84 determines whether the distance from the edge of the field to the rice transplanter 1 is equal to or greater than the notification distance (S205), and if it is equal to or greater than the notification distance, notifies the operator that the turning start position is approaching (S206). There are various ways to notify the operator, such as by generating a warning sound or displaying a warning on the display unit 73. This makes it possible to notify the operator of the appropriate timing to stop the rice transplanter 1 (in other words, the appropriate turning start position).

[0065] In the first embodiment, stopping during the reverse stroke is premised on an operation by the operator. In contrast, in the second embodiment, information regarding distances such as the minimum distance and the notified distance is obtained. Therefore, the rice transplanter 1 may be stopped autonomously by the control unit 50. In addition, in the first and second embodiments, switching from the forward stroke to the reverse stroke is performed by the operator by setting the main shift lever 28 to the "reverse" position. In contrast, after the rice transplanter 1 has stopped, a predetermined actuator may automatically switch the rice transplanter 1 to a reverse state to start the reverse stroke.

[0066] In the second embodiment, as in the first embodiment, one of the turning start conditions is the operator's forward operation (S207). However, in the second embodiment, a distance condition regarding the distance to the edge of the field is also set as one of the turning start conditions. The distance condition is a condition regarding the distance for turning the rice transplanter 1 so as not to come into contact with the edge of the field. Therefore, the distance condition is, for example, that the current distance from the rice transplanter 1 to the edge of the field is greater than the minimum distance. Note that, since some margin is necessary, the distance condition may be set using a value slightly greater than the minimum distance. The notification unit 84 determines whether the distance condition is met after the operator's forward operation (S208). If the distance condition is not met, the notification unit 84 notifies the operator that turning is difficult (S209). If turning is difficult, the control unit 50 stops the rice transplanter 1 (S210). In this case, the operator reverses the rice transplanter 1 again to a position where turning is possible, and then turns the rice transplanter 1. Note that the processing from step S207 onwards may be performed again after the rice transplanter 1 has completed reverse travel. In this way, in the second embodiment, by performing processing related to the distance condition, it is possible to prevent the rice transplanter 1 from autonomously making an unreasonable turn even in a situation where the reverse travel distance is insufficient.

[0067] Furthermore, if the distance condition is satisfied, the turning start condition is satisfied, and therefore the turning control unit 53 causes the rice transplanter 1 to turn autonomously to the next straight path 91a (S211).

[0068] Note that only some of the features of the second embodiment may be applied to the first embodiment. For example, if the distance condition for starting autonomous traveling is predetermined and measurement of the first distance is not necessary, only the feature of including the distance condition in the turning start condition may be applied to the first embodiment.

[0069] As described above, the autonomous driving system 100 of the above embodiment includes a path creation unit 82, a forward control unit 51, a reverse control unit 52, and a turning control unit 53. The path creation unit 82 creates multiple straight paths 91a arranged side by side in the field. The forward control unit 51 autonomously performs at least steering to cause the rice transplanter 1 to travel along the straight paths 91a while causing the rice transplanter 1 to perform work. After the operator stops the rice transplanter 1 traveling toward the edge of the field, the reverse control unit 52 reverses the rice transplanter 1 in response to the operator's operation or autonomously without causing the rice transplanter 1 to perform work. After the reverse control unit 52 stops the rice transplanter 1 while it is traveling backward by the operator or autonomously, and on the condition that the operator has given a forward command, the turning control unit 53 autonomously performs at least steering to turn the rice transplanter 1 toward the pre-specified straight path without causing the rice transplanter 1 to perform work.

[0070] This allows the operator to stop the rice transplanter 1 near the edge of the field, allowing the rice transplanter 1 to work closer to the edge of the field than if it were stopped autonomously. As a result, the area in which the rice transplanter 1 works along a straight path can be widened. Also, by making the forward command from the operator one of the turning start conditions, the operator's commands are simplified and turning can be started even earlier.

[0071] In addition, in the autonomous driving system 100 of the above embodiment, the turning control unit 53 sets a turning path (second turning path 91c) that connects to the pre-specified straight path 91a, and turns the rice transplanter 1 along the second turning path 91c.

[0072] As a result, by setting the second turning path 91c, the rice transplanter 1 can be turned more reliably to the straight path 91a.

[0073] Furthermore, in the autonomous driving system 100 of the above embodiment, the reverse control unit 52 does not cause the rice transplanter 1 to perform work, but autonomously performs at least steering to cause the rice transplanter 1 to move backward along the straight path 91a.

[0074] This allows the rice transplanter 1 to pass through approximately the same position when moving forward and backward, preventing travel marks from being left in unnecessary positions.

[0075] The autonomous driving system 100 of the second embodiment also includes a calculation unit 83 and a notification unit 84. The calculation unit 83 calculates a first distance, which is the distance traveled by the rice transplanter 1 while the measurement conditions are satisfied, while the rice transplanter 1 is traveling toward the edge of the field. The notification unit 84 notifies the operator of information regarding the stopping position of the rice transplanter 1 based on the first distance while the rice transplanter 1 is traveling backward by the reverse control unit 52.

[0076] This allows the operator to know the position where the rice transplanter 1 should be stopped when the rice transplanter 1 is moving backward.

[0077] Furthermore, in the autonomous traveling system 100 of the second embodiment, the calculation unit 83 further calculates a distance condition, which is a condition regarding the distance from the rice transplanter 1 to the edge of the field, based on the first distance. The distance condition is further included as a condition for the turning control unit 53 to start turning the rice transplanter 1.

[0078] This prevents the machine from starting to turn if it is too close to the edge of the field, for example, and thus makes it possible to prevent unreasonable turning.

[0079] The preferred embodiment of the present invention has been described above, but the above configuration can be modified, for example, as follows.

[0080] In the above embodiment, the forward movement process is automatically started after the turning process is completed. However, the rice transplanter 1 may be temporarily stopped after the turning process is completed. This allows the operator to replenish the chemicals placed on the ridge to the chemical tank at the rear of the rice transplanter 1. It may also be possible to set whether or not to temporarily stop the rice transplanter 1 after the turning process. Furthermore, it may be possible to temporarily stop the rice transplanter 1 after the turning process only once every several times (or only at a predetermined position).

[0081] <Notes on the invention> According to an aspect of the present invention, there is provided an autonomous driving system having the following configuration. Specifically, this autonomous driving system includes a path creation unit, a forward control unit, a reverse control unit, and a turning control unit. The path creation unit creates a plurality of straight paths arranged side by side in a field. The forward control unit autonomously performs at least steering to cause the work vehicle to travel along the straight paths while causing the work vehicle to perform work. The reverse control unit, after an operator stops the work vehicle traveling toward the edge of the field, causes the work vehicle to move backward in response to an operation by the operator or autonomously, without causing the work vehicle to perform work. The turning control unit, after the reverse control unit has stopped the work vehicle while traveling backward, either by the operator or autonomously, and on the condition that a forward command has been given by the operator, autonomously performs at least steering to turn the work vehicle toward the pre-specified straight path without causing the work vehicle to perform work.

[0082] This allows the operator to stop the work vehicle near the edge of the field, allowing it to work closer to the edge of the field than if it were stopped autonomously.As a result, the area in which the work vehicle can work along a straight path can be expanded.In addition, by making the forward command from the operator one of the conditions for starting a turn, the operator's commands are simplified and turning can be started even earlier.

[0083] In the autonomous driving system, it is preferable that the turning control unit sets a turning path that connects to the pre-specified straight path, and turns the work vehicle along the turning path.

[0084] This allows the work vehicle to more reliably turn onto a straight path by setting a turning path.

[0085] In the autonomous driving system, it is preferable that the reverse control unit autonomously performs at least steering to reverse the work vehicle along the straight path without causing the work vehicle to perform work.

[0086] This allows the work vehicle to pass through approximately the same position when moving forward and backward, preventing driving marks from being left in unnecessary positions.

[0087] The autonomous driving system preferably has the following configuration. That is, the autonomous driving system includes a calculation unit and a notification unit. The calculation unit calculates a first distance, which is the distance traveled by the work vehicle while a measurement condition is satisfied, while the work vehicle is traveling toward the edge of the field. The notification unit notifies the operator of information regarding the stopping position of the work vehicle based on the first distance while the work vehicle is traveling in reverse due to the reverse control unit.

[0088] This allows the operator to know the position where the work vehicle should be stopped when the work vehicle is moving in reverse.

[0089] The autonomous driving system is preferably configured as follows: That is, the calculation unit further calculates a distance condition, which is a condition related to the distance from the work vehicle to the edge of the field, based on the first distance. The distance condition is further included as a condition for the turning control unit to start turning the work vehicle.

[0090] This prevents the machine from starting to turn if it is too close to the edge of the field, for example, and thus makes it possible to prevent unreasonable turning. [Explanation of symbols]

[0091] 1 Rice transplanter (work vehicle) 51 Forward control section 52 Reverse control unit 53 Swivel control section 82 Route Creation Department 83 Calculation Unit 100 Autonomous Driving System

Claims

1. a switching operation unit for switching between forward and reverse movement of the work vehicle; a reverse control unit that reverses the work vehicle that has stopped at the edge of the field on the condition that a reverse operation has been performed on the switching operation unit; a turning control unit that, after the reverse control unit has autonomously stopped the work vehicle during reverse travel, autonomously performs at least steering to turn the work vehicle, After the turning control unit has turned, at least steering is performed autonomously to cause the work vehicle to travel. Autonomous driving system.

2. The turning control unit After the reverse control unit autonomously stops the work vehicle while it is moving backward, the work vehicle is turned on the condition that an instruction to move forward is given by an operator, When the reverse control unit is moving the work vehicle backward, the work vehicle is not turned even if the operator issues the forward command. The autonomous driving system according to claim 1 .

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