Route generation system and route generation method for automatic driving of agricultural machinery

Abstract

To avoid collision between an implement of a work vehicle and an oncoming vehicle.SOLUTION: A travel control system is a system that controls automatic traveling of an agricultural work vehicle to which an implement can be mounted. The travel control system includes a control device that causes the work vehicle to perform collision avoidance traveling in which, when the work vehicle passes an oncoming vehicle in a road outside a field in a state where an implement having a width larger than the work vehicle is mounted in the work vehicle, a front part of the work vehicle comes close to the center side of the road and a rear part of the work vehicle comes close to an end side of the road, so that the work vehicle passes the oncoming vehicle while avoiding collision between the implement and the oncoming vehicle.SELECTED DRAWING: Figure 10C

Description

Technical Field

[0001] The present disclosure relates to a route generation system and a route generation method for automatic driving of agricultural machines.

Background Art

[0002] Research and development for automating agricultural machines used in fields are underway. For example, work vehicles such as tractors, combines, and rice transplanters that automatically drive within a field using a positioning system such as GNSS (Global Navigation Satellite System) have been put into practical use. Research and development of work vehicles that automatically drive not only within the field but also outside the field are also underway.

[0003] Patent Documents 1 and 2 disclose examples of systems for automatically driving unmanned work vehicles between two fields separated from each other by a road.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0005] Work vehicles such as tractors perform agricultural work with an implement (working machine) attached to the rear or front. Some implements have a width wider than that of the work vehicle. When the work vehicle automatically drives on a road outside the field (for example, a farm road or a general road) with such a wide implement attached, it is difficult to avoid a collision between the implement and an oncoming vehicle.

[0006] The present disclosure provides a technique for avoiding a collision between an implement of a work vehicle and an oncoming vehicle. **Means for Solving the Problems**

[0007] A travel control system according to an exemplary embodiment of the present disclosure is a system for controlling the automatic travel of an agricultural work vehicle capable of mounting an implement. When the work vehicle passes by an oncoming vehicle on a road outside the field while mounting an implement wider than the work vehicle at the rear, the travel control system causes the front part of the work vehicle to approach the center side of the road and the rear part of the work vehicle to approach the edge side of the road, and includes a control device that causes the work vehicle to perform a collision avoidance travel for passing by while avoiding a collision between the implement and the oncoming vehicle.

[0008] A travel control method according to another exemplary embodiment of the present disclosure is a method for controlling the automatic travel of an agricultural work vehicle capable of mounting an implement. The travel control method includes causing the work vehicle to perform a collision avoidance travel for passing by while avoiding a collision between the implement and the oncoming vehicle when the work vehicle passes by an oncoming vehicle on a road outside the field while mounting an implement wider than the work vehicle at the rear. Causing the work vehicle to perform the collision avoidance travel includes controlling the work vehicle so that the work vehicle passes by the oncoming vehicle in a state where the front part of the work vehicle approaches the center side of the road and the rear part of the work vehicle approaches the edge side of the road.

[0009] The comprehensive or specific aspects of the present disclosure can be realized by an apparatus, a system, a method, an integrated circuit, a computer program, or a non-transitory computer-readable storage medium, or any combination thereof. The computer-readable storage medium may include a volatile storage medium or a non-volatile storage medium. The apparatus may be composed of a plurality of apparatuses. When the apparatus is composed of two or more apparatuses, the two or more apparatuses may be arranged in one device or may be separately arranged in two or more separate devices.

Advantages of the Invention

[0010] According to the embodiments of the present disclosure, it is possible to avoid a collision between an implement of a work vehicle and an oncoming vehicle.

Brief Description of the Drawings

[0011]

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Embodiments for Carrying Out the Invention

[0012] (Definition of Terms) In the present disclosure, a "work vehicle" means a vehicle used for performing work at a work site. The "work site" is any place where work is carried out, such as a farm field, a mountain forest, or a construction site. The "farm field" is any place where agricultural work is carried out, such as an orchard, a field, a paddy field, a grain farm, or a pasture. The work vehicle can be, for example, an agricultural machine such as a tractor, a rice transplanter, a combine harvester, a ride-on mower, or a ride-on lawn mower, or a vehicle used for non-agricultural purposes such as a construction work vehicle or a snowplow. The work vehicle in the present disclosure can be equipped with an implement (also referred to as a "work implement" or a "work device") corresponding to the work content at the rear or the front. The act of the work vehicle traveling while performing work may be referred to as "work traveling".

[0013] "Agricultural machine" means a machine used for agricultural purposes. Examples of agricultural machines include tractors, harvesters, rice transplanters, ride-on mowers, vegetable transplanters, lawn mowers, seeders, fertilizer spreaders, and agricultural mobile robots. Not only when a work vehicle such as a tractor functions alone as an "agricultural machine", but also when the implement attached to or towed by the work vehicle and the entire work vehicle function as one "agricultural machine". Agricultural machines perform agricultural work such as tilling, seeding, pest control, fertilizing, planting crops, or harvesting on the ground in a farm field.

[0014] "Autonomous driving" means controlling the running of a vehicle by the function of a control device without manual operation by a driver. During autonomous driving, not only the running of the vehicle but also the operations of work (for example, the operations of implements) may be automatically controlled. The running of a vehicle by autonomous driving is called "automatic driving". The control device can control at least one of steering necessary for the running of the vehicle, adjustment of running speed, and start and stop of running. When controlling a work vehicle equipped with an implement, the control device may control operations such as raising and lowering of the implement, and start and stop of the operations of the implement. The running by autonomous driving may include not only the running of the vehicle along a predetermined route towards a destination but also the running following a following target. A vehicle performing autonomous driving may run partially based on an instruction of a user. Further, a vehicle performing autonomous driving may operate in a manual driving mode in which the vehicle runs by manual operation of a driver in addition to the autonomous driving mode. Performing the steering of a vehicle by the function of a control device without manual operation is called "automatic steering". Part or all of the control device may be outside the vehicle. Communication such as control signals, commands, or data may be performed between the control device outside the vehicle and the vehicle. A vehicle performing autonomous driving may autonomously run while sensing the surrounding environment without a person's involvement in the control of the running of the vehicle. A vehicle capable of autonomous running can run without a driver. During autonomous running, detection of obstacles and obstacle avoidance operations may be performed.

[0015] "Environmental map" is data representing the positions or areas of objects existing in the environment in which a work vehicle runs by a predetermined coordinate system. Examples of the coordinate system defining the environmental map include not only world coordinate systems such as a geographic coordinate system fixed to the earth but also an odometry coordinate system displaying a pose based on odometry information. The environmental map may include information other than the position (for example, attribute information or other information) about the objects existing in the environment. The environmental map includes various forms of maps such as a point cloud map or a grid map.

[0016] "Farm road" means a road mainly used for agricultural purposes. A farm road includes not only roads paved with asphalt but also unpaved roads covered with soil, gravel, etc. A farm road includes roads (including private roads) that only vehicles such as agricultural machinery (e.g., work vehicles such as tractors) can exclusively pass through and roads that ordinary vehicles (passenger cars, trucks, buses, etc.) can also pass through. A work vehicle may automatically drive on general roads in addition to farm roads. A general road is a road maintained for the traffic of ordinary vehicles.

[0017] (Embodiment) Hereinafter, embodiments of the present disclosure will be described. However, a more detailed description may be omitted as necessary. For example, a detailed description of well-known matters and overlapping descriptions regarding substantially the same configuration may be omitted. This is to avoid making the following description unnecessarily redundant and to facilitate the understanding of those skilled in the art. Note that the inventors provide the accompanying drawings and the following description for those skilled in the art to fully understand the present disclosure, and do not intend to limit the subject matter described in the claims by these. In the following description, components having the same or similar functions are denoted by the same reference numerals.

[0018] The following embodiments are examples, and the technology of the present disclosure is not limited to the following embodiments. For example, the numerical values, shapes, materials, steps, order of steps, layout of the display screen, etc. shown in the following embodiments are merely examples, and various modifications are possible as long as there is no technical contradiction. Also, as long as there is no technical contradiction, it is possible to combine one aspect with another aspect.

[0019] Hereinafter, an embodiment in which the technology of the present disclosure is applied to a tractor, which is an example of a work vehicle, will be described. The technology of the present disclosure can be applied not only to tractors but also to other types of work vehicles that can mount implements.

[0020] FIG. 1 is a diagram for explaining an overview of an agricultural management system according to an exemplary embodiment of the present disclosure. The agricultural management system shown in FIG. 1 includes a work vehicle 100, a terminal device 400, and a management device 600. The terminal device 400 is a computer used by a user who remotely monitors the work vehicle 100. The management device 600 is a computer managed by an operator who operates the agricultural management system. The work vehicle 100, the terminal device 400, and the management device 600 can communicate with each other via a network 80. Although one work vehicle 100 is illustrated in FIG. 1, the agricultural management system may include a plurality of work vehicles or other agricultural machines.

[0021] The work vehicle 100 in the present embodiment is a tractor. The work vehicle 100 can attach implements to one or both of the rear and front parts. The work vehicle 100 can travel in the field while performing agricultural work according to the type of implement. The work vehicle 100 may travel in or outside the field without attaching an implement.

[0022] The work vehicle 100 is provided with an automatic driving function. That is, the work vehicle 100 can travel by the action of a control device without manual operation. The control device in the present embodiment is provided inside the work vehicle 100 and can control both the speed and steering of the work vehicle 100. The work vehicle 100 can automatically drive not only in the field but also outside the field (for example, on a road).

[0023] The work vehicle 100 is equipped with devices such as a GNSS receiver and a LiDAR sensor, which are used for positioning or self-position estimation. The control device of the work vehicle 100 automatically drives the work vehicle 100 based on the position of the work vehicle 100 and the information of the target route. In addition to the driving control of the work vehicle 100, the control device also controls the operation of the implement. Thereby, the work vehicle 100 can perform agricultural work using the implement while automatically driving in the field. Furthermore, the work vehicle 100 can automatically drive along the target route on the road outside the field (for example, a farm road or a general road). When the work vehicle 100 performs automatic driving along the road outside the field, it travels while generating a local route capable of avoiding obstacles based on the data output from a sensing device such as a camera or a LiDAR sensor along the target route (hereinafter, also referred to as the "global route"). In the field, the work vehicle 100 may travel while generating a local route in the same manner as described above, or may travel along the target route without generating a local route and stop when an obstacle is detected.

[0024] The management device 600 is a computer that manages the agricultural work by the work vehicle 100. The management device 600 can be, for example, a server computer that centrally manages information about the field on the cloud and supports agriculture by utilizing the data on the cloud. The management device 600 may, for example, create a work plan for the work vehicle 100 and generate a target route for the work vehicle 100 according to the work plan. The management device 600 may generate a target route based on the information indicating the route or waypoint specified by the user operating the terminal device 400 regardless of the work plan. The management device 600 may further generate and edit an environmental map based on the data collected by the work vehicle 100 or other moving bodies using a sensing device such as a LiDAR sensor. The management device 600 transmits the generated work plan, target route, and environmental map data to the work vehicle 100. The work vehicle 100 automatically performs movement and agricultural work based on those data.

[0025] The terminal device 400 is a computer used by a user located at a location away from the work vehicle 100. The terminal device 400 shown in FIG. 1 is a laptop computer, but is not limited thereto. The terminal device 400 may be a stationary computer such as a desktop PC (personal computer), or may be a mobile terminal such as a smartphone or a tablet computer. The terminal device 400 can be used to remotely monitor the work vehicle 100 or remotely operate the work vehicle 100. For example, the terminal device 400 can display on a display a video captured by one or more cameras (imaging devices) provided in the work vehicle 100. The user can view the video, check the situation around the work vehicle 100, and send an instruction to stop or start the work vehicle 100.

[0026] Hereinafter, the configuration and operation of the system in the present embodiment will be described in more detail.

[0027] [1. Configuration] FIG. 2 is a side view schematically showing an example of the work vehicle 100 and the implement 300 connected to the work vehicle 100. The work vehicle 100 in the present embodiment can operate in both a manual driving mode and an automatic driving mode. In the automatic driving mode, the work vehicle 100 can travel unmanned. The work vehicle 100 can perform automatic driving both inside and outside the farm field.

[0028] As shown in FIG. 2, the work vehicle 100 includes a vehicle body 101, a prime mover (engine) 102, and a transmission 103. The vehicle body 101 is provided with a wheel 104 with a tire and a cabin 105. The wheel 104 includes a pair of front wheels 104F and a pair of rear wheels 104R. Inside the cabin 105, a driver's seat 107, a steering device 106, an operation terminal 200, and a switch group for operation are provided. When the work vehicle 100 performs work running in the farm field, one or both of the front wheels 104F and the rear wheels 104R may be replaced with a plurality of wheels (crawlers) equipped with endless tracks instead of the wheels with tires.

[0029] The work vehicle 100 includes a plurality of sensing devices that sense the surroundings of the work vehicle 100. In the example of FIG. 2, the sensing devices include a plurality of cameras 120, a LiDAR sensor 140, and a plurality of obstacle sensors 130.

[0030] The cameras 120 can be provided, for example, on the front, rear, left, and right of the work vehicle 100. The cameras 120 photograph the environment around the work vehicle 100 and generate image data. The images acquired by the cameras 120 can be transmitted to a terminal device 400 for remote monitoring. The images can be used to monitor the work vehicle 100 during unmanned driving. The cameras 120 can also be used for generating images for recognizing surrounding features or obstacles, white lines, signs, or displays, etc. when the work vehicle 100 is traveling on a road (rural road or general road) outside the farm field.

[0031] In the example of FIG. 2, the LiDAR sensor 140 is disposed at the lower front part of the vehicle body 101. The LiDAR sensor 140 may be provided at other positions. The LiDAR sensor 140 repeatedly outputs sensor data indicating the distance and direction to each measurement point of an object existing in the surrounding environment, or the two-dimensional or three-dimensional coordinate values of each measurement point, while the work vehicle 100 is mainly traveling outside the farm field. The sensor data output from the LiDAR sensor 140 is processed by a control device of the work vehicle 100. The control device can estimate the self-position of the work vehicle 100 by matching the sensor data with an environmental map. The control device can further detect objects such as obstacles existing around the work vehicle 100 based on the sensor data, and generate a local path that the work vehicle 100 should actually travel along a global path. The control device can also generate or edit an environmental map by using an algorithm such as SLAM (Simultaneous Localization and Mapping). The work vehicle 100 may include a plurality of LiDAR sensors arranged at different positions and in different orientations.

[0032] The plurality of obstacle sensors 130 shown in FIG. 2 are provided at the front and rear of the cabin 105. The obstacle sensors 130 may also be arranged at other locations. For example, one or more obstacle sensors 130 may be provided at any position on the sides, front, and rear of the vehicle body 101. The obstacle sensor 130 may include, for example, a laser scanner or an ultrasonic sonar. The obstacle sensor 130 is used to detect surrounding obstacles during automatic driving to stop or detour the work vehicle 100. The LiDAR sensor 140 may be used as one of the obstacle sensors 130.

[0033] The work vehicle 100 further includes a GNSS unit 110. The GNSS unit 110 includes a GNSS receiver. The GNSS receiver may include an antenna for receiving signals from GNSS satellites and a processor for calculating the position of the work vehicle 100 based on the signals received by the antenna. The GNSS unit 110 receives satellite signals transmitted from a plurality of GNSS satellites and performs positioning based on the satellite signals. GNSS is a general term for satellite positioning systems such as GPS (Global Positioning System), QZSS (Quasi-Zenith Satellite System, such as Michibiki), GLONASS, Galileo, and BeiDou. The GNSS unit 110 in this embodiment is provided on the upper part of the cabin 105, but may be provided at other positions.

[0034] The GNSS unit 110 may include an inertial measurement unit (IMU). The position data can be complemented using signals from the IMU. The IMU can measure the inclination and minute movements of the work vehicle 100. By using the data obtained by the IMU to complement the position data based on satellite signals, the positioning performance can be improved.

[0035] In addition to the positioning result by the GNSS unit 110, the control device of the work vehicle 100 may use the sensing data acquired by a sensing device such as the camera 120 or the LiDAR sensor 140 for positioning. When there are features that function as feature points in the environment where the work vehicle 100 travels, such as rural roads, forest roads, general roads, or orchards, based on the data acquired by the camera 120 or the LiDAR sensor 140 and the environmental map stored in the storage device in advance, the position and orientation of the work vehicle 100 can be estimated with high accuracy. By using the data acquired by the camera 120 or the LiDAR sensor 140 to correct or complement the position data based on satellite signals, the position of the work vehicle 100 can be specified with higher accuracy.

[0036] The prime mover 102 can be, for example, a diesel engine. An electric motor may be used instead of the diesel engine. The transmission 103 can change the propulsion force and moving speed of the work vehicle 100 by shifting gears. The transmission 103 can also switch between the forward and reverse of the work vehicle 100.

[0037] The steering device 106 includes a steering wheel, a steering shaft connected to the steering wheel, and a power steering device that assists steering by the steering wheel. The front wheels 104F are steering wheels, and by changing their steering angle (also referred to as "steering angle"), the traveling direction of the work vehicle 100 can be changed. The steering angle of the front wheels 104F can be changed by operating the steering wheel. The power steering device includes a hydraulic device or an electric motor that supplies an assisting force for changing the steering angle of the front wheels 104F. When automatic steering is performed, the steering angle is automatically adjusted by the force of the hydraulic device or the electric motor under the control from the control device arranged inside the work vehicle 100.

[0038] A coupling device 108 is provided at the rear of the vehicle body 101. The coupling device 108 includes, for example, a three-point support device (also referred to as a "three-point link" or "three-point hitch"), a PTO (Power Take Off) shaft, a universal joint, and a communication cable. The implement 300 can be attached to and detached from the work vehicle 100 by the coupling device 108. The coupling device 108 can raise and lower the three-point link by, for example, a hydraulic device to change the position or attitude of the implement 300. Also, power can be transmitted from the work vehicle 100 to the implement 300 via the universal joint. The work vehicle 100 can cause the implement 300 to perform a predetermined operation while pulling the implement 300. The coupling device may be provided in front of the vehicle body 101. In that case, an implement can be connected in front of the work vehicle 100.

[0039] The implement 300 shown in FIG. 2 is a rotary tiller, but the implement 300 is not limited to a rotary tiller. For example, any implement such as a seeder, a spreader, a transplanter, a mower, a rake, a baler, a harvester, a sprayer, or a harrow can be connected to the work vehicle 100 and used.

[0040] The work vehicle 100 shown in FIG. 2 can be manned, but may also be compatible only with unmanned operation. In that case, components necessary only for manned operation, such as the cab 105, the steering device 106, and the driver's seat 107, may not be provided on the work vehicle 100. The unmanned work vehicle 100 can travel by autonomous driving or remote operation by the user.

[0041] FIG. 3 is a block diagram showing a configuration example of the work vehicle 100 and the implement 300. The work vehicle 100 and the implement 300 can communicate with each other via the communication cable included in the coupling device 108. The work vehicle 100 can communicate with the terminal device 400 and the management device 600 via the network 80.

[0042] In the example of the work vehicle 100 in FIG. 3, in addition to the GNSS unit 110, the camera 120, the obstacle sensor 130, the LiDAR sensor 140, and the operation terminal 200, the work vehicle 100 is provided with a sensor group 150 that detects the operating state of the work vehicle 100, a travel control system 160, a communication device 190, an operation switch group 210, a buzzer 220, and a travel drive device 240. These components are connected to be communicable with each other via a bus. The GNSS unit 110 includes a GNSS receiver 111, an RTK receiver 112, an inertial measurement unit (IMU) 115, and a processing circuit 116. The sensor group 150 includes a steering wheel sensor 152, a cut angle sensor 154, and an axle sensor 156. The control system 160 includes a storage device 170 and a control device 180. The control device 180 includes a plurality of electronic control units (ECUs) 181 to 186. The implement 300 includes a drive device 340, a control device 380, and a communication device 390. Note that FIG. 3 shows components that are relatively highly related to the operation of the automatic driving by the work vehicle 100, and illustration of other components is omitted.

[0043] The GNSS receiver 111 in the GNSS unit 110 receives satellite signals transmitted from a plurality of GNSS satellites and generates GNSS data based on the satellite signals. The GNSS data is generated in a predetermined format such as, for example, the NMEA-0183 format. The GNSS data may include, for example, values indicating the identification number, elevation angle, azimuth angle, and reception intensity of each satellite from which the satellite signal is received.

[0044] The GNSS unit 110 shown in FIG. 3 performs positioning of the work vehicle 100 using RTK (Real Time Kinematic)-GNSS. FIG. 4 is a conceptual diagram showing an example of a work vehicle 100 that performs positioning by RTK-GNSS. In positioning by RTK-GNSS, in addition to satellite signals transmitted from a plurality of GNSS satellites 50, correction signals transmitted from a reference station 60 are used. The reference station 60 can be installed near a field where the work vehicle 100 performs work driving (for example, at a position within 10 km from the work vehicle 100). The reference station 60 generates correction signals in, for example, RTCM format based on satellite signals received from a plurality of GNSS satellites 50 and transmits them to the GNSS unit 110. The RTK receiver 112 includes an antenna and a modem and receives correction signals transmitted from the reference station 60. The processing circuit 116 of the GNSS unit 110 corrects the positioning result by the GNSS receiver 111 based on the correction signals. By using RTK-GNSS, it is possible to perform positioning with an accuracy of, for example, several centimeters of error. Position information including latitude, longitude, and altitude information is obtained by high-precision positioning by RTK-GNSS. The GNSS unit 110 calculates the position of the work vehicle 100, for example, at a frequency of about once to ten times per second.

[0045] Note that the positioning method is not limited to RTK-GNSS, and any positioning method (such as an interferometric positioning method or a relative positioning method) that can obtain position information with the required accuracy can be used. For example, positioning using VRS (Virtual Reference Station) or DGPS (Differential Global Positioning System) may be performed. When position information with the required accuracy can be obtained without using the correction signals transmitted from the reference station 60, the position information may be generated without using the correction signals. In that case, the GNSS unit 110 may not include the RTK receiver 112.

[0046] Even when using RTK-GNSS, in a location where a correction signal from the reference station 60 cannot be obtained (for example, on a road far from the farm field), the position of the work vehicle 100 is estimated by other methods regardless of the signal from the RTK receiver 112. For example, the position of the work vehicle 100 can be estimated by matching the data output from the LiDAR sensor 140 and / or the camera 120 with a high-precision environmental map.

[0047] The GNSS unit 110 in the present embodiment further includes an IMU 115. The IMU 115 can include a three-axis acceleration sensor and a three-axis gyroscope. The IMU 115 may include an azimuth sensor such as a three-axis geomagnetic sensor. The IMU 115 functions as a motion sensor and can output signals indicating various quantities such as the acceleration, speed, displacement, and orientation of the work vehicle 100. The processing circuit 116 can estimate the position and orientation of the work vehicle 100 with higher accuracy based on the signals output from the IMU 115 in addition to the satellite signals and correction signals. The signals output from the IMU 115 can be used for correcting or complementing the position calculated based on the satellite signals and correction signals. The IMU 115 outputs signals at a higher frequency than the GNSS receiver 111. Using the high-frequency signals, the processing circuit 116 can measure the position and orientation of the work vehicle 100 at a higher frequency (for example, 10 Hz or more). Instead of the IMU 115, a three-axis acceleration sensor and a three-axis gyroscope may be provided separately. The IMU 115 may be provided as a device separate from the GNSS unit 110.

[0048] The camera 120 is an imaging device that captures the environment around the work vehicle 100. The camera 120 includes, for example, an image sensor such as a CCD (Charge Coupled Device) or a CMOS (Complementary Metal Oxide Semiconductor). The camera 120 may also include an optical system including one or more lenses and a signal processing circuit. During the travel of the work vehicle 100, the camera 120 captures the environment around the work vehicle 100 and generates image (e.g., video) data. The camera 120 can capture video, for example, at a frame rate of 3 frames per second (fps) or more. The image generated by the camera 120 can be used, for example, when a remote monitor uses the terminal device 400 to check the environment around the work vehicle 100. The image generated by the camera 120 may also be used for positioning or obstacle detection. As shown in FIG. 2, a plurality of cameras 120 may be provided at different positions of the work vehicle 100, or a single camera may be provided. A visible camera that generates a visible light image and an infrared camera that generates an infrared image may be provided separately. Both the visible camera and the infrared camera may be provided as cameras that generate monitoring images. The infrared camera can also be used for detecting obstacles at night.

[0049] The obstacle sensor 130 detects an object existing around the work vehicle 100. The obstacle sensor 130 may include, for example, a laser scanner or an ultrasonic sonar. When an object exists closer than a predetermined distance from the obstacle sensor 130, the obstacle sensor 130 outputs a signal indicating the presence of an obstacle. A plurality of obstacle sensors 130 may be provided at different positions of the work vehicle 100. For example, a plurality of laser scanners and a plurality of ultrasonic sonars may be arranged at different positions of the work vehicle 100. By providing such a large number of obstacle sensors 130, dead spots in monitoring obstacles around the work vehicle 100 can be reduced.

[0050] The steering wheel sensor 152 measures the rotation angle of the steering wheel of the work vehicle 100. The steering angle sensor 154 measures the steering angle of the front wheels 104F which are the steered wheels. The measurement values by the steering wheel sensor 152 and the steering angle sensor 154 are used for the steering control by the control device 180.

[0051] The axle sensor 156 measures the rotational speed of the axle connected to the wheel 104, that is, the number of rotations per unit time. The axle sensor 156 can be, for example, a sensor using a magnetoresistive element (MR), a Hall element, or an electromagnetic pickup. The axle sensor 156 outputs, for example, a numerical value indicating the number of rotations per minute (unit: rpm) of the axle. The axle sensor 156 is used to measure the speed of the work vehicle 100.

[0052] The drive device 240 includes various devices necessary for the running of the work vehicle 100 and the driving of the implement 300, such as the aforementioned prime mover 102, transmission 103, steering device 106, and coupling device 108. The prime mover 102 can be equipped with an internal combustion engine such as a diesel engine. The drive device 240 may be equipped with a traction electric motor instead of or together with the internal combustion engine.

[0053] The buzzer 220 is an audio output device that emits a warning sound for notifying an abnormality. The buzzer 220 emits a warning sound, for example, when an obstacle is detected during automatic driving. The buzzer 220 is controlled by the control device 180.

[0054] The storage device 170 includes one or more storage media such as a flash memory or a magnetic disk. The storage device 170 stores various data generated by the GNSS unit 110, the camera 120, the obstacle sensor 130, the LiDAR sensor 140, the sensor group 150, and the control device 180. The data stored in the storage device 170 may include map data (environmental map) of the environment in which the work vehicle 100 travels and data of a global route (target route) for autonomous driving. The environmental map includes information on a plurality of farms where the work vehicle 100 performs farming operations and the roads around them. The environmental map and the target route can be generated by a processor in the management device 600. Note that the control device 180 in the present embodiment has a function of generating or editing the environmental map and the target route. The control device 180 can edit the environmental map and the target route acquired from the management device 600 according to the driving environment of the work vehicle 100. The storage device 170 also stores the data of the work plan received by the communication device 190 from the management device 600. The work plan includes information on a plurality of farming operations to be performed by the work vehicle 100 over a plurality of work days. The work plan can be, for example, data of a work schedule including information on the scheduled times of each farming operation to be performed by the work vehicle 100 on each work day. The storage device 170 also stores a computer program that causes each ECU in the control device 180 to execute various operations described later. Such a computer program can be provided to the work vehicle 100 via a storage medium (for example, a semiconductor memory or an optical disk, etc.) or a telecommunication line (for example, the Internet). Such a computer program may be sold as commercial software.

[0055] The control device 180 includes a plurality of ECUs. The plurality of ECUs include, for example, an ECU 181 for speed control, an ECU 182 for steering control, an ECU 183 for implement control, an ECU 184 for autonomous driving control, an ECU 185 for route generation, and an ECU 186 for map generation.

[0056] The ECU 181 controls the speed of the work vehicle 100 by controlling the prime mover 102, the transmission 103, and the brake included in the drive device 240.

[0057] The ECU 182 controls the steering of the work vehicle 100 by controlling the hydraulic device or the electric motor included in the steering device 106 based on the measured value of the steering wheel sensor 152.

[0058] The ECU 183 controls operations such as the three-point link and the PTO shaft included in the hitch 108 in order to cause the implement 300 to perform a desired operation. The ECU 183 also generates a signal for controlling the operation of the implement 300 and transmits the signal from the communication device 190 to the implement 300.

[0059] The ECU 184 performs calculations and controls for realizing autonomous driving based on the data output from the GNSS unit 110, the camera 120, the obstacle sensor 130, the LiDAR sensor 140, and the sensor group 150. For example, the ECU 184 identifies the position of the work vehicle 100 based on the data output from at least one of the GNSS unit 110, the camera 120, and the LiDAR sensor 140. In the field, the ECU 184 may determine the position of the work vehicle 100 based only on the data output from the GNSS unit 110. The ECU 184 may estimate or correct the position of the work vehicle 100 based on the data acquired by the camera 120 or the LiDAR sensor 140. By using the data acquired by the camera 120 or the LiDAR sensor 140, the positioning accuracy can be further improved. Also, outside the field, the ECU 184 estimates the position of the work vehicle 100 by using the data output from the LiDAR sensor 140 or the camera 120. For example, the ECU 184 may estimate the position of the work vehicle 100 by matching the data output from the LiDAR sensor 140 or the camera 120 with the environmental map. During autonomous driving, the ECU 184 performs the calculations necessary for the work vehicle 100 to travel along the target route or the local route based on the estimated position of the work vehicle 100. The ECU 184 sends a command for changing the speed to the ECU 181 and a command for changing the steering angle to the ECU 182. The ECU 181 changes the speed of the work vehicle 100 by controlling the prime mover 102, the transmission 103, or the brake in response to the command for changing the speed. The ECU 182 changes the steering angle by controlling the steering device 106 in response to the command for changing the steering angle.

[0060] While the work vehicle 100 is traveling along the target route, the ECU 185 sequentially generates a local route capable of avoiding obstacles. While the work vehicle 100 is traveling, the ECU 185 recognizes obstacles existing around the work vehicle 100 based on the data output from the camera 120, the obstacle sensor 130, and the LiDAR sensor 140. The ECU 185 generates a local route so as to avoid the recognized obstacles. The ECU 185 may have a function of generating a target route instead of the management device 600. In that case, the ECU 185 determines the destination of the work vehicle 100 based on, for example, a work plan stored in the storage device 170, and determines a target route from the starting point to the destination of the movement of the work vehicle 100. The ECU 185 can create, as a target route, a route that can reach the destination in the shortest time, for example, based on an environmental map including road information stored in the storage device 170.

[0061] The ECU 186 generates or edits a map of the environment in which the work vehicle 100 travels. In the present embodiment, an environmental map generated by an external device such as the management device 600 is transmitted to the work vehicle 100 and recorded in the storage device 170, but the ECU 186 can also generate or edit the environmental map instead. Hereinafter, the operation when the ECU 186 generates an environmental map will be described. The environmental map can be generated based on the sensor data output from the LiDAR sensor 140. When generating the environmental map, the ECU 186 sequentially generates three-dimensional point cloud data based on the sensor data output from the LiDAR sensor 140 while the work vehicle 100 is traveling. The ECU 186 can generate an environmental map by connecting the sequentially generated point cloud data using an algorithm such as SLAM. The environmental map generated in this way is a high-precision three-dimensional map and can be used for self-position estimation by the ECU 184. Based on this three-dimensional map, a two-dimensional map used for global route planning can be generated. In this specification, both the three-dimensional map used for self-position estimation and the two-dimensional map used for route planning are referred to as "environmental map".

[0062] By the functions of these ECUs, the control device 180 realizes autonomous driving. During autonomous driving, the control device 180 controls the drive device 240 based on the measured or estimated position of the work vehicle 100 and the target route. Thereby, the control device 180 can make the work vehicle 100 travel along the target route.

[0063] The plurality of ECUs included in the control device 180 can communicate with each other according to a vehicle bus standard such as CAN (Controller Area Network). Instead of CAN, a faster communication method such as in-vehicle Ethernet (registered trademark) may be used. In FIG. 3, each of the ECUs 181 to 186 is shown as an individual block, but each of these functions may be realized by a plurality of ECUs. An in-vehicle computer integrating at least some of the functions of the ECUs 181 to 186 may be provided. The control device 180 may include ECUs other than the ECUs 181 to 186, and any number of ECUs can be provided according to the functions. Each ECU includes a processing circuit including one or more processors.

[0064] The communication device 190 is a device including a circuit for communicating with the implement 300, the terminal device 400, and the management device 600. The communication device 190 includes a circuit for performing transmission and reception of signals compliant with the ISOBUS standard such as ISOBUS-TIM, for example, with the communication device 390 of the implement 300. Thereby, it is possible to cause the implement 300 to execute a desired operation or to acquire information from the implement 300. The communication device 190 may further include an antenna and a communication circuit for performing transmission and reception of signals via the network 80 with each communication device of the terminal device 400 and the management device 600. The network 80 may include, for example, a cellular mobile communication network such as 3G, 4G, or 5G and the Internet. The communication device 190 may have a function of communicating with a mobile terminal used by a monitor near the work vehicle 100. Communication compliant with any wireless communication standard such as Wi-Fi (registered trademark), cellular mobile communication such as 3G, 4G, or 5G, or Bluetooth (registered trademark) may be performed with such a mobile terminal.

[0065] The operation terminal 200 is a terminal for a user to perform operations related to the running of the work vehicle 100 and the operation of the implement 300, and is also referred to as a virtual terminal (VT). The operation terminal 200 may include a display device such as a touch screen and / or one or more buttons. The display device may be a display such as a liquid crystal or an organic light emitting diode (OLED). By operating the operation terminal 200, the user can perform various operations such as switching on / off the automatic driving mode, recording or editing the environmental map, setting the target route, and switching on / off the implement 300. At least some of these operations may also be realized by operating the operation switch group 210. The operation terminal 200 may be configured to be removable from the work vehicle 100. A user located away from the work vehicle 100 may operate the removed operation terminal 200 to control the operation of the work vehicle 100. Instead of the operation terminal 200, the user may operate a computer such as the terminal device 400 in which the necessary application software is installed to control the operation of the work vehicle 100.

[0066] FIG. 5 is a diagram showing an example of the operation terminal 200 and the operation switch group 210 provided inside the cabin 105. Inside the cabin 105, an operation switch group 210 including a plurality of switches operable by the user is arranged. The operation switch group 210 may include, for example, a switch for selecting a gear stage of the main transmission or the auxiliary transmission, a switch for switching between the automatic driving mode and the manual driving mode, a switch for switching between forward and reverse, and a switch for raising and lowering the implement 300. Note that when the work vehicle 100 only performs unmanned driving and does not have a manned driving function, the work vehicle 100 does not need to be provided with the operation switch group 210.

[0067] In the implement 300 shown in FIG. 3, the drive device 340 performs operations necessary for the implement 300 to execute a predetermined task. The drive device 340 includes a device suitable for the use of the implement 300, such as a hydraulic device, an electric motor, or a pump. The control device 380 controls the operation of the drive device 340. The control device 380 causes the drive device 340 to perform various operations in response to a signal transmitted from the work vehicle 100 via the communication device 390. Further, a signal corresponding to the state of the implement 300 can be transmitted from the communication device 390 to the work vehicle 100.

[0068] [2. Operation] Next, the operation of the work vehicle 100 will be described.

[0069] [2-1. Automatic driving operation] First, an example of the automatic driving operation by the work vehicle 100 will be described. The work vehicle 100 in the present embodiment can automatically drive both inside and outside the field. Inside the field, the work vehicle 100 drives the implement 300 to perform a predetermined farming operation while traveling along a target route set in the field. When an obstacle is detected by the obstacle sensor 130 while the work vehicle 100 is traveling inside the field, the work vehicle 100 stops traveling and performs operations such as emitting a warning sound from the buzzer 220 and transmitting a warning signal to the terminal device 400. Inside the field, the positioning of the work vehicle 100 is mainly performed based on data output from the GNSS unit 110. On the other hand, outside the field, the work vehicle 100 automatically travels along a target route set on a farm road or a general road outside the field. The work vehicle 100 travels while generating a local route based on data acquired by the camera 120 or the LiDAR sensor 140 while traveling outside the field. Outside the field, when an obstacle is detected, the work vehicle 100 avoids the obstacle or stops on the spot. Outside the field, the position of the work vehicle 100 is estimated based on data output from the LiDAR sensor 140 or the camera 120 in addition to the positioning data output from the GNSS unit 110.

[0070] The operation when the work vehicle 100 automatically travels within the farm field will be described below. The operation when the work vehicle 100 automatically travels outside the farm field will be described later.

[0071] FIG. 6 is a diagram schematically showing an example of a work vehicle 100 that automatically travels along a target route within a farm field. In this example, the farm field includes a work area 72 where the work vehicle 100 performs work using the implement 300, and a headland 74 located near the outer peripheral edge of the farm field. Which area of the farm field corresponds to the work area 72 or the headland 74 on the map can be set in advance by the user. The target route in this example includes a plurality of parallel main routes P1 and a plurality of turning routes P2 that connect the plurality of main routes P1. The main route P1 is located within the work area 72, and the turning route P2 is located within the headland 74. Each main route P1 shown in FIG. 6 is a straight route, but each main route P1 may include a curved portion. The dashed line in FIG. 6 represents the working width of the implement 300. The working width is preset and recorded in the storage device 170. The working width can be set and recorded by the user operating the operation terminal 200 or the terminal device 400. Alternatively, the working width may be automatically recognized and recorded when the implement 300 is connected to the work vehicle 100. The interval between the plurality of main routes P1 can be set according to the working width. The target route can be created based on the user's operation before the start of the automatic driving. The target route can be created, for example, to cover the entire work area 72 within the farm field. The work vehicle 100 automatically travels along the target route as shown in FIG. 6, repeating back and forth from the start point of the work to the end point of the work. Note that the target route shown in FIG. 6 is only an example, and the method of determining the target route is arbitrary.

[0072] Next, an example of the control during automatic driving by the control device 180 will be described.

[0073] FIG. 7 is a flowchart showing an example of the operation of steering control during automatic driving executed by the control device 180. While the work vehicle 100 is traveling, the control device 180 performs automatic steering by executing the operations of steps S121 to S125 shown in FIG. 7. Regarding the speed, for example, it is maintained at a preset speed. While the work vehicle 100 is traveling, the control device 180 acquires data indicating the position of the work vehicle 100 generated by the GNSS unit 110 (step S121). Next, the control device 180 calculates the deviation between the position of the work vehicle 100 and the target path (step S122). The deviation represents the distance between the position of the work vehicle 100 at that time and the target path. The control device 180 determines whether or not the calculated position deviation exceeds a preset threshold value (step S123). If the deviation exceeds the threshold value, the control device 180 changes the steering angle by changing the control parameter of the steering device included in the drive device 240 so that the deviation becomes smaller. If the deviation does not exceed the threshold value in step S123, the operation of step S124 is omitted. In the subsequent step S125, the control device 180 determines whether or not a command to end the operation has been received. The command to end the operation can be issued, for example, when the user remotely instructs to stop the automatic driving or when the work vehicle 100 reaches the destination. If the command to end the operation has not been issued, the process returns to step S121, and the same operation is executed based on the newly measured position of the work vehicle 100. The control device 180 repeats the operations of steps S121 to S125 until a command to end the operation is issued. The above operations are executed by the ECUs 182 and 184 in the control device 180.

[0074] In the example shown in FIG. 7, the control device 180 controls the drive device 240 based only on the deviation between the position of the work vehicle 100 specified by the GNSS unit 110 and the target path, but it may also control by further considering the deviation in azimuth. For example, when the azimuth deviation, which is the angular difference between the direction of the work vehicle 100 specified by the GNSS unit 110 and the direction of the target path, exceeds a preset threshold value, the control device 180 may change the control parameter (for example, the steering angle) of the steering device of the drive device 240 according to the deviation.

[0075] Hereinafter, an example of steering control by the control device 180 will be described more specifically with reference to FIGS. 8A to 8D.

[0076] FIG. 8A is a diagram showing an example of the work vehicle 100 traveling along the target path P. FIG. 8B is a diagram showing an example of the work vehicle 100 at a position shifted to the right from the target path P. FIG. 8C is a diagram showing an example of the work vehicle 100 at a position shifted to the left from the target path P. FIG. 8D is a diagram showing an example of the work vehicle 100 facing in a direction inclined with respect to the target path P. In these figures, the pose indicating the position and orientation of the work vehicle 100 measured by the GNSS unit 110 is expressed as r(x, y, θ). (x, y) are coordinates representing the position of the reference point of the work vehicle 100 in the XY coordinate system, which is a two-dimensional coordinate system fixed to the earth. In the examples shown in FIGS. 8A to 8D, the reference point of the work vehicle 100 is at the position where the GNSS antenna on the cabin is installed, but the position of the reference point is arbitrary. θ is an angle representing the measured orientation of the work vehicle 100. In the illustrated example, the target path P is parallel to the Y-axis, but generally the target path P is not necessarily parallel to the Y-axis.

[0077] As shown in FIG. 8A, when the position and orientation of the work vehicle 100 are not deviated from the target path P, the control device 180 maintains the steering angle and speed of the work vehicle 100 without changing them.

[0078] As shown in FIG. 8B, when the position of the work vehicle 100 is shifted to the right from the target path P, the control device 180 changes the steering angle so that the traveling direction of the work vehicle 100 inclines to the left and approaches the path P. At this time, in addition to the steering angle, the speed may also be changed. The magnitude of the steering angle can be adjusted according to, for example, the magnitude of the position deviation Δx.

[0079] As shown in FIG. 8C, when the position of the work vehicle 100 has shifted to the left from the target path P, the control device 180 changes the steering angle so that the traveling direction of the work vehicle 100 inclines to the right and approaches the path P. Also in this case, the speed may be changed together with the steering angle. The amount of change in the steering angle can be adjusted according to, for example, the magnitude of the position deviation Δx.

[0080] As shown in FIG. 8D, when the position of the work vehicle 100 is not greatly deviated from the target path P but the direction is different from the direction of the target path P, the control device 180 changes the steering angle so that the azimuth deviation Δθ becomes smaller. Also in this case, the speed may be changed together with the steering angle. The magnitude of the steering angle can be adjusted according to, for example, the magnitudes of the position deviation Δx and the azimuth deviation Δθ respectively. For example, the smaller the absolute value of the position deviation Δx, the larger the amount of change in the steering angle corresponding to the azimuth deviation Δθ may be made. When the absolute value of the position deviation Δx is large, the steering angle will be changed greatly to return to the path P, so inevitably the absolute value of the azimuth deviation Δθ will become large. Conversely, when the absolute value of the position deviation Δx is small, it is necessary to make the azimuth deviation Δθ approach zero. For this reason, it is reasonable to relatively increase the weight (i.e., control gain) of the azimuth deviation Δθ for determining the steering angle.

[0081] For the steering control and speed control of the work vehicle 100, control techniques such as PID control or MPC control (model predictive control) can be applied. By applying these control techniques, the control to bring the work vehicle 100 closer to the target path P can be made smooth.

[0082] When an obstacle is detected by one or more obstacle sensors 130 during traveling, the control device 180 stops the work vehicle 100. At this time, a warning sound may be emitted from the buzzer 220, or a warning signal may be transmitted to the terminal device 400. When it is possible to avoid the obstacle, the control device 180 may control the drive device 240 to avoid the obstacle.

[0083] The work vehicle 100 in this embodiment can automatically travel not only within the field but also outside the field. Outside the field, the control device 180 can detect an object (for example, another vehicle or a pedestrian, etc.) existing at a position relatively far from the work vehicle 100 based on the data output from the camera 120 or the LiDAR sensor 140. The control device 180 generates a local path to avoid the detected object, and realizes automatic driving on the road outside the field by performing the above speed control and steering control along the local path.

[0084] In this way, the work vehicle 100 in this embodiment can automatically travel inside and outside the field. FIG. 9 is a diagram schematically showing an example of a situation where a plurality of work vehicles 100 are automatically traveling on the road outside the field 70 and inside the field 70. In the storage device 170, an environmental map and a target path of an area including a plurality of fields 70 and the surrounding roads 76 are recorded. The environmental map and the target path can be generated by the management device 600, the control device 180, the operation terminal 200, or the terminal device 400. When the work vehicle 100 travels on the road, the work vehicle 100 travels along the target path while sensing the surroundings using sensing devices such as the camera 120 and the LiDAR sensor 140 with the implement 300 in the raised state. During traveling, the control device 180 sequentially generates a local path along the target path, and performs steering control so that the work vehicle 100 travels along the local path. Thereby, it is possible to automatically travel while avoiding obstacles. During traveling, the target path may be changed according to the situation.

[0085] [2-2. Operation to Avoid oncoming Vehicles] When the work vehicle 100 is traveling along a road outside the field, an oncoming vehicle may approach from the front of the work vehicle 100. In that case, the control device 180 of the work vehicle 100 executes an operation to avoid the oncoming vehicle. For example, when the work vehicle 100 passes by an oncoming vehicle on a road outside the field while the work vehicle 100 is equipped with an implement 300 that is wider than the work vehicle 100 at the rear, the control device 180 causes the work vehicle 100 to perform a collision avoidance driving in which the front part of the work vehicle 100 moves closer to the center side of the road and the rear part of the work vehicle 100 moves closer to the edge side of the road, so as to avoid a collision between the implement 300 and the oncoming vehicle. Hereinafter, this operation will be specifically described.

[0086] FIG. 10A schematically shows an example of a situation in which an oncoming vehicle exists in front of the work vehicle 100A when the work vehicle 100A is automatically traveling along a road 76 (for example, a farm road) outside the field 70. The oncoming vehicle in this example is a work vehicle 100B similar to the work vehicle 100A. The work vehicle 100B is an autonomous tractor similar to the work vehicle 100A. The oncoming vehicle may be a different type of vehicle from the work vehicle 100A and may not have an autonomous driving function. Here, an example in which both the work vehicles 100A and 100B have the configuration of the above-described work vehicle 100 (see, for example, FIG. 3) will be described. In the following description, the work vehicle 100B will also be referred to as the "oncoming vehicle 100B".

[0087] The work vehicle 100A is equipped with an implement 300A at the rear. The width of the implement 300A in this example is larger than the width of the work vehicle 100A. The oncoming vehicle, the work vehicle 100B, is a tractor similar to the work vehicle 100A and is equipped with an implement 300B at the rear. The width of the implement 300B is larger than the width of the work vehicle 100B.

[0088] In the example shown in FIG. 10A, the widths of the implements 300A and 300B are wide. When the work vehicle 100A and the oncoming vehicle 100B attempt to pass each other in the normal way, the implement 300A and the implement 300B will collide. Here, the normal way refers to the method in which the work vehicle 100A approaches one end of the road 76 and the oncoming vehicle 100B approaches the opposite end of the road 76 and they pass each other. FIG. 10B shows an example of a situation where the implement 300A and the implement 300B collide. The dashed arrows in FIG. 10B show examples of the travel trajectories of the work vehicle 100A and the oncoming vehicle 100B. In the example of FIG. 10B, since the width of the road 76 is narrow and the widths of the implements 300A and 300B are wide, the implement 300A and the implement 300B collide during passing. Even when the oncoming vehicle 100B is not equipped with the implement 300B, if the road width is narrow, there is a possibility that the implement 300A and the oncoming vehicle 100B will collide.

[0089] To avoid collisions, the work vehicle 100A in the present embodiment performs a collision avoidance travel in which the front part approaches the center side of the road 76 and the rear part approaches the end side of the road 76, while avoiding a collision between the implement 300A and the oncoming vehicle 100B. Here, "the collision between the implement 300A and the oncoming vehicle 100B" includes not only the collision between the implement 300A and the vehicle body of the oncoming vehicle 100B, but also the collision between the implement 300A and the implement 300B of the oncoming vehicle 100B.

[0090] Figure 10C shows an example of a work vehicle 100A performing collision avoidance driving. In this example, the oncoming vehicle 100B is also performing similar collision avoidance driving. In the example of Figure 10C, the control device 180 first changes the traveling direction of the work vehicle 100A in a direction away from the center of the road 76, and then changes it in a direction approaching the center of the road 76. In Figure 10C, the center line 76c representing the center of the road 76 is shown by a dashed line. In the example of Figure 10C, the oncoming vehicle 100B also performs the same operation as the work vehicle 100A. As a result, the work vehicle 100A and the oncoming vehicle 100B travel along a trajectory as shown by the dashed arrows in Figure 10C, for example, and pass by each other. The driving for such passing is referred to as "collision avoidance driving" in this specification. By the collision avoidance driving, a collision between the implement 300A of the work vehicle 100A and the implement 300B (or the vehicle body or tires) of the oncoming vehicle 100B can be avoided.

[0091] In the example of Figure 10C, the control device 180 determines the collision avoidance driving route so that a part of the implement 300A protrudes outside the road 76. By performing the collision avoidance driving with a part of the implement 300A protruding outside the road 76, it becomes easier to avoid a collision between the implement 300A and the oncoming vehicle 100B. When the work vehicle 100A travels on the road 76 outside the farm field 70, the implement 300A is at a position higher than the surface of the road 76. Therefore, for example, when the farm field 70 is at a position lower than the road 76, there is no problem even if a part of the implement 300A protrudes outside the road 76.

[0092] Figures 11A to 11F show an example of the change in the position and orientation of each vehicle when both the work vehicle 100A and the oncoming vehicle 100B perform collision avoidance driving. The work vehicle 100A and the oncoming vehicle 100B can pass by each other without colliding by traveling along the trajectories shown in Figures 11A to 11F.

[0093] Incidentally, the oncoming vehicle 100B may travel by manual driving by the driver. Even in this case, if the driver drives the oncoming vehicle 100B along the same trajectory as described above, the collision can be avoided in the same manner. Also, even when the oncoming vehicle 100B travels straight after approaching the edge of the road 76 as in the example of FIG. 10B, the work vehicle 100A performs the above-described collision avoidance travel according to the position of the oncoming vehicle 100B, thereby avoiding the collision.

[0094] The control device 180 in the present embodiment causes the work vehicle 100A to travel along a target route set on the road 76 outside the field 70 based on the position information of the work vehicle 100A output from a positioning device (for example, the GNSS unit 110 or the like) provided in the work vehicle 100A and the environmental map stored in the storage device 170. When the oncoming vehicle 100B is detected while the control device 180 is causing the work vehicle 100A to travel along the target route, the control device 180 determines whether to execute collision avoidance travel for the work vehicle 100A. When the control device 180 determines to execute the collision avoidance travel for the work vehicle 100A, the control device 180 generates a route for the collision avoidance travel and causes the work vehicle 100A to travel along the route. Hereinafter, the above operations will be described in more detail.

[0095] FIG. 12 is a flowchart showing an example of a control method for collision avoidance travel. In the example of FIG. 12, when controlling the automatic travel of the work vehicle 100A, the control device 180 executes the operations from steps S200 to S206. Hereinafter, the operations of each step will be described.

[0096] In step S200, the control device 180 acquires the position information of the oncoming vehicle 100B. For example, the control device 180 can acquire the position information of the oncoming vehicle 100B via a network. Each work vehicle 100 that automatically travels within the area around the farm field 70, including the work vehicles 100A and 100B, can be configured to sequentially transmit its own position information acquired by a positioning device (such as the GNSS unit 110, etc.) to the management device 600. In that case, the control device 180 can acquire the position information of the oncoming vehicle 100B from the management device 600 via the network. Alternatively, the control device 180 may acquire the position information of the oncoming vehicle 100B by estimation based on the sensor data output from the sensing devices (such as the LiDAR sensor 140 and / or the camera 120, etc.) provided in the work vehicle 100A and the environmental map.

[0097] In step S201, the control device 180 determines whether the oncoming vehicle 100B exists on the travel path of the work vehicle 100A. For example, the control device 180 determines whether the oncoming vehicle 100B exists within a range within a predetermined distance (such as 10 m, 20 m, or 30 m, etc.) in front of the work vehicle 100A based on the position of the work vehicle 100A measured by the positioning device and the position of the oncoming vehicle 100B. The position of the work vehicle 100A can be acquired, for example, from a positioning device (such as the GNSS unit 110, etc.) provided in the work vehicle 100A. The positioning device may be a device that performs self-position estimation by matching the data output from the camera 120 and / or the LiDAR sensor 140 with the environmental map. In the configuration example of FIG. 3, the ECU 184 can function as such a positioning device that performs self-position estimation. When the oncoming vehicle 100B is detected on the travel path of the work vehicle 100A, the process proceeds to step S202. When the oncoming vehicle 100B is not detected, the process proceeds to step S205, and the travel control along the current path is continued.

[0098] In step S202, the control device 180 determines whether collision avoidance driving is necessary. The control device 180 acquires information such as the width of the road 76 and the width of the implement 300A of the work vehicle 100A, for example, and determines whether collision avoidance driving is necessary based on those widths. As in the example shown in FIG. 10B, when the work vehicle 100A cannot avoid a collision just by approaching the edge of the road 76, the control device 180 determines that collision avoidance driving is necessary. A more specific example of this determination will be described later. If it is determined that collision avoidance driving is necessary, the process proceeds to step S203. If it is determined that collision avoidance driving is not necessary, the process proceeds to step S204.

[0099] In step S203, the control device 180 generates a path for collision avoidance driving. For example, as shown in FIG. 10C, the control device 180 generates a path in which, after approaching the edge of the road 76, the front part of the work vehicle 100A approaches the center side of the road 76 and the rear part approaches the edge side of the road 76 and then proceeds. A specific example of the method for determining the path for collision avoidance driving will be described later.

[0100] In step S204, the control device 180 performs normal path generation processing. For example, as indicated by the dashed arrow in FIG. 10B, the control device 180 generates a path in which it approaches the edge of the road 76 and then proceeds straight.

[0101] In step S205, the control device 180 controls the traveling drive device 240 of the work vehicle 100A so that the work vehicle 100A travels along the generated path. Here, when it is determined in step S201 that there is no oncoming vehicle on the route, the control device 180 causes the work vehicle 100A to travel along the previously generated path. When a collision avoidance travel path is generated in step S203, the control device 180 causes the work vehicle 100A to travel along the collision avoidance travel path. When a normal avoidance operation path is generated in step S204, the control device 180 causes the work vehicle 100A to travel along the normal avoidance operation path. The control device 180 performs steering control of the work vehicle 100A in the same manner as the method described with reference to FIGS. 8A to 8D, for example. The control device 180 may set the traveling speed of the work vehicle 100 during collision avoidance travel to be lower than the traveling speed of the work vehicle 100 before and after collision avoidance travel.

[0102] In step S206, the control device 180 determines whether a command to end the operation has been received. A command to end the operation may be issued, for example, when the user remotely instructs to stop the automatic driving or when the work vehicle 100 reaches the destination. If a command to end the operation has not been issued, the process returns to step S200. The control device 180 repeats the operations from step S200 to S206 until a command to end the operation is issued. The above operations can be executed by the ECUs 182, 184, and 185 in the control device 180.

[0103] By the above operations, a collision between the work vehicle 100A and the oncoming vehicle 100B can be effectively avoided.

[0104] Next, a specific example of a method for determining whether collision avoidance travel in step S202 is necessary will be described.

[0105] The control device 180 may be configured to acquire information on the widths of the implement 300A and the road 76 respectively, and determine whether to execute collision avoidance driving for the work vehicle 100A based on the widths of the implement 300A and the road 76. For example, when the control device 180 determines, based on the information on the widths of the implement 300A and the road 76 respectively, that the work vehicle 100A cannot avoid a collision with the oncoming vehicle 100B just by approaching the edge of the road 76 as shown in the example of FIG. 10B, the control device 180 causes the work vehicle 100A to execute collision avoidance driving.

[0106] Information such as the width of each road 76, the width of the work vehicle 100A, and the width of the implement 300A in the environment in which the work vehicle 100A travels may be pre-recorded in the storage device 170 of the work vehicle 100A. The information on the width of the implement 300A may be input by the user, or may be automatically input from the implement 300A when the implement 300A is attached to the work vehicle 100A. The information on the width of the road 76 may be included in the map data as attribute information of the environmental map. Alternatively, the width of the road 76 may be calculated by a process based on an image captured by the camera 120 when the work vehicle 100A has traveled on the road 76 in the past. The control device 180 may acquire the information on the width of the road 76 from an external device such as the management device 600 via a network.

[0107] The control device 180 may further acquire information on the width of the oncoming vehicle 100B, and further determine whether to execute collision avoidance driving for the work vehicle based on the width of the oncoming vehicle 100B. Here, when the oncoming vehicle 100B is equipped with an implement 300B having a width larger than the width of the oncoming vehicle 100B, the width of the implement 300B is treated as the "width of the oncoming vehicle 100B". The work vehicle 100A may acquire in advance, from an external device (for example, the management device 600) via a network, information such as the position and width of the oncoming work vehicle 100B and the width of the implement 300B.

[0108] FIG. 13 illustrates the widths of the road 76, the work vehicles 100A and 100B, and the implements 300A and 300B respectively. As shown in FIG. 13, let the width of the road 76 be W R , the width of the work vehicle 100A be W V1 , the width of the implement 300A be W I1 , the width of the work vehicle 100B be W V2 , and the width of the implement 300B be W I2 . Here, the width of each of the work vehicles 100A and 100B and the implements 300A and 300B refers to the width of the widest part among them.

[0109] The control device 180 may be configured to determine whether to execute collision avoidance driving for the work vehicle 100A based on the width W I1 of the implement 300A and the width W R of the road 76. For example, when the width W I1 of the implement 300A is greater than a value obtained by multiplying half of the width W R of the road 76 by a first coefficient of 1 or less, collision avoidance driving may be executed for the work vehicle 100A. The first coefficient may be set to a value close to 1, such as 1.0, 0.9, or 0.8. The first coefficient may be, for example, 0.7 or more and 1.0 or less. When the width W I1 of the implement 300A is smaller than half of the width W R of the road 76, it is possible to avoid a collision with the oncoming vehicle 100B even with the normal avoidance operation shown in FIG. 10B. Therefore, when the width W I1 of the implement 300A is less than or equal to a value obtained by multiplying half of the width W R of the road 76 by a first coefficient of 1 or less, the control device 180 may execute the normal avoidance operation shown in FIG. 10B.

[0110] Whether a collision occurs depends not only on the width W I1 of the implement 300A and the width W R of the road 76, but also on the width of the oncoming vehicle 100B (in this example, the width W I2 of the implement 300B). Therefore, the control device 180, for example, the width W I1and the sum with the width of the oncoming vehicle 100B (width W of the implement I2 ) is greater than the value obtained by multiplying the road width W R by a second coefficient of 1 or less, collision avoidance driving may be executed for the work vehicle 100A. The second coefficient can be set to a value close to 1, such as 1.0, 0.9, or 0.8, for example. The second coefficient can be set to a value of 0.7 or more and 1.0 or less, for example. The width W I1 of the implement 300A I2 and the width W R of the implement I1 If the sum with the width W I2 of the implement of the oncoming vehicle 100B R is less than the value obtained by multiplying the road width W by a second coefficient of 1 or less, the normal avoidance operation shown in FIG. 10B may be executed.

[0111] Here, the conditions under which the implements 300A and 300B do not collide with each other will be considered in more detail. As shown in FIG. 13, consider a situation where the work vehicle 100A is close to one end of the road 76 and the work vehicle 100B is close to the opposite end of the road 76, and the work vehicles 100A and 100B are moving straight in opposite directions to each other. In this case, if the following inequality (1) is satisfied, the implements 300A and 300B will not collide with each other.

Equation

[0112] Equation (1) is transformed into the following equation (2).

Equation

[0113] That is, the width W V1 of the work vehicle 100A I1 and the width W V2 of the implement 300AI2 Half of the sum with is the width W of Road 76 R If it is smaller than, collision between the implements 300A and 300B does not occur.

[0114] However, in reality, since the work vehicles 100A and 100B travel slightly inside from the edge of Road 76, even if the above inequality (2) is satisfied, a collision may occur. Therefore, with k as a positive coefficient of 1 or less, when the control device 180 satisfies the following formula (3), it may perform normal control shown in FIG. 10B, and when it does not satisfy formula (3), it may perform collision avoidance travel control shown in FIG. 10C.

Equation

[0115] Note that the width W of the work vehicle 100B V2 is equal to the width W of the work vehicle 100A V1 and the width W of the implement 300B I2 is equal to the width W of the implement 300A I1 In this case, formula (3) is transformed into the following formula (4).

Equation

[0116] In this case, when the control device 180 satisfies formula (4), it may perform normal control shown in FIG. 10B, and when it does not satisfy formula (4), it may perform collision avoidance travel control shown in FIG. 10C.

[0117] Next, a specific example of the method for determining the collision avoidance travel route in step S203 of FIG. 12 will be described.

[0118] The control device 180 may be configured to determine the collision avoidance travel route based on the width W of the implement 300A I1 and the width W of Road 76 R For example, the control device 180 may determine the width W of the implement 300A I1 and the width W of Road 76 RBased on this, when the work vehicle 100A passes by the oncoming vehicle 100B, the collision avoidance driving path may be determined so that one end of the implement 300A does not cross the center line 76C of the road 76.

[0119] FIGS. 14A and 14B are diagrams for explaining the conditions that the collision avoidance driving path should satisfy. In these figures, the local path of the collision avoidance driving is indicated by a thick arrow. The control device 180 determines the local path and repeats the operation of driving the work vehicle 100A along the local path. Thereby, the work vehicle 100A performs collision avoidance driving as shown in FIGS. 11A to 11F. The local path is a path having a relatively short length (for example, about several tens of centimeters to several meters). The control device 180 detects obstacles such as oncoming vehicles 100B in the surroundings based on the data output from the sensing devices such as the LiDAR sensor 140, the camera 120, and the obstacle sensor 130, and sequentially determines the local path so as to avoid the obstacles.

[0120] As shown in FIG. 14A, let the angle formed by the traveling direction of the work vehicle 100A at a certain moment (the direction of the thick arrow in the figure) and the direction in which the center line 76c of the road 76 extends (the upward direction in the figure) be θ. Also, let the intersection of the straight line passing through the center of the work vehicle 100A and extending in the traveling direction and the center line 76c of the road 76 be C, and the distance between the point C and the front end of the work vehicle 100A be L. θ and L are parameters controlled for passing by the oncoming vehicle 100B. As shown in FIG. 14A, let the length of the work vehicle 100A be L V1 and the distance from the lower link at the rear of the work vehicle 100A to the center of the implement 300A be L I1 From the condition that one end of the implement 300A does not cross the center line 76C of the road 76, it is necessary to satisfy the following inequality (5).

Equation

[0121] Equation (5) is transformed into the following equation (6).

Equation

[0122] Therefore, the control device 180 can be configured to determine a local path for collision avoidance driving such that L and θ satisfy the inequality (6).

[0123] Also, as shown in FIG. 14B, it is required that among the two rear wheels of the work vehicle 100A, the rear wheel located on the edge side of the road 76 does not protrude outside the road 76. For this purpose, it is necessary to satisfy the following inequality (7).

Equation

[0124] Equation (7) is transformed into the following equation (8).

Equation

[0125] Therefore, the control device 180 can be configured to determine a local path for collision avoidance driving such that L and θ satisfy the inequality (8).

[0126] W R 、W V1 、W I1 、L V1 、L I1 are fixed values that can be obtained from road information or the specifications of the work vehicle 100A and the implement 300A. By controlling the work vehicle 100A such that L and θ satisfy both inequalities (6) and (8), the control device 180 can avoid one end of the implement 300A exceeding the center line 76C of the road 76 or the rear wheels of the work vehicle 100 protruding outside the road 76. Thereby, a path for collision avoidance driving to avoid a collision with the oncoming vehicle 100B can be appropriately set.

[0127] The control device 180 may further determine an avoidance driving route based on the width of the oncoming vehicle 100B. For example, the avoidance driving route may be determined so as to satisfy the following formula (9) in which a positive coefficient k2 less than or equal to 1 determined according to the width of the oncoming vehicle 100B is multiplied by the left side of formula (5).

Number

[0128]

[0129] ​The system for performing autonomous driving control in each of the above embodiments can also be retrofitted to agricultural machines that do not have those functions. Such a system can be manufactured and sold independently of the agricultural machine. A computer program used in such a system can also be manufactured and sold independently of the agricultural machine. The computer program can be provided, for example, stored in a computer-readable non-transitory storage medium. The computer program can also be provided by downloading via a telecommunication line (e.g., the Internet).

[0130] As described above, the present disclosure includes a travel control system, a work vehicle, and a travel control method described in the following items.

[0131] [Item 1] A travel control system for controlling the autonomous travel of an agricultural work vehicle capable of mounting an implement, when the work vehicle passes by an oncoming vehicle on a road outside the field while mounting an implement wider than the work vehicle at the rear, the front part of the work vehicle is closer to the center side of the road, and the rear part of the work vehicle is closer to the edge side of the road, and a control device that causes the work vehicle to perform a collision avoidance travel to pass by while avoiding a collision between the implement and the oncoming vehicle. A travel control system.

[0132] [Item 2] The control device determines the route of the collision avoidance travel so that a part of the implement protrudes outside the road. The travel control system according to Item 1.

[0133] [Item 3] The control device acquires information on the width of the implement and the width of the road, and determines the route of the collision avoidance travel based on the width of the implement and the width of the road. The travel control system according to Item 1 or 2.

[0134] [Item 4] The control device further acquires information on the width of the oncoming vehicle, and determines the path for collision avoidance driving based further on the width of the oncoming vehicle, the driving control system according to item 3.

[0135] [Item 5] The control device acquires information on the width of the implement and the width of the road respectively, and determines whether to execute the collision avoidance driving on the work vehicle based on the width of the implement and the width of the road, the driving control system according to any one of items 1 to 4.

[0136] [Item 6] When the width of the implement is greater than the value obtained by multiplying the width of the road by a first coefficient of 1 or less, the control device causes the work vehicle to execute the collision avoidance driving, the driving control system according to item 5.

[0137] [Item 7] The control device further acquires information on the width of the oncoming vehicle, and determines whether to execute the collision avoidance driving on the work vehicle based further on the width of the oncoming vehicle, the driving control system according to item 5.

[0138] [Item 8] When the sum of the width of the implement and the width of the oncoming vehicle is greater than the value obtained by multiplying the width of the road by a second coefficient of 1 or less, the control device causes the work vehicle to execute the collision avoidance driving, the driving control system according to item 7.

[0139] [Item 9] When the oncoming vehicle is another work vehicle equipped with another implement and the width of the other implement is greater than the width of the other work vehicle, the control device acquires information indicating the width of the other implement as information indicating the width of the oncoming vehicle, the driving control system according to any one of items 4, 7, and 8.

[0140] [Item 10] The control device is the driving control system according to any one of items 4, 7 to 9, which acquires information on the width of the oncoming vehicle and the width of the road from an external device via a network.

[0141] [Item 11] When the oncoming vehicle is detected based on data output from a sensing device provided in the work vehicle, the control device determines whether to execute the collision avoidance driving for the work vehicle. The driving control system according to any one of items 1 to 10.

[0142] [Item 12] The control device acquires the position information of the oncoming vehicle via a network, acquires the position information of the work vehicle from a positioning device provided in the work vehicle, and determines whether to execute the collision avoidance driving for the work vehicle when the oncoming vehicle is detected on the travel route of the work vehicle based on the position information of the work vehicle and the position information of the oncoming vehicle. The driving control system according to item 1.

[0143] [Item 13] The control device further includes a storage device that stores an environmental map. The control device Based on the position information of the work vehicle output from a positioning device provided in the work vehicle and the environmental map, the work vehicle is driven along a target route set on the road outside the field. When the oncoming vehicle is detected while the work vehicle is being driven along the target route, it is determined whether to execute the collision avoidance driving for the work vehicle. The driving control system according to item 11.

[0144] [Item 14] The driving control system according to any one of items 1 to 12, and A travel drive device controlled by the control device, A work vehicle including the same.

[0145] [Item 15] A travel control method for controlling the automatic travel of an agricultural work vehicle capable of mounting an implement, when the work vehicle passes by an oncoming vehicle on a road outside the field with a wider implement than the work vehicle mounted on the rear part, including causing the work vehicle to perform a collision avoidance travel to pass by while avoiding a collision between the implement and the oncoming vehicle, causing the work vehicle to perform the collision avoidance travel includes controlling the work vehicle so that the front part of the work vehicle approaches the center side of the road and the rear part of the work vehicle approaches the edge side of the road, and the work vehicle passes by the oncoming vehicle. Travel control method.

Industrial Applicability

[0146] The technology of the present disclosure can be applied to a system for controlling the automatic travel of a work vehicle capable of mounting an implement, such as a tractor or a construction work vehicle.

Explanation of Signs

[0147] 50 GNSS satellites 60 reference stations 70 fields 72 work areas 74 headlands 76 farm roads 80 network 100 work vehicle 101 vehicle body 102 prime mover (engine) 103 transmission 104 wheels 105 cabin 106 steering device 107 driver's seat 108 coupling device 110 GNSS unit 111 GNSS receiver 112 RTK receiver 115 inertial measurement unit (IMU) 116 processing circuit 120 camera 130 Obstacle sensor 140 LiDAR sensor 150 Sensor group 152 Steering wheel sensor 154 Corner sensor 156 Axle sensor 160 Driving control system 170 Memory device 180 Control device 181 - 186 ECU 190 Communication device 200 Operating terminal 210 Operation switch group 220 Buzzer 240 Driving device 300 Implement 340 Driving device 380 Control device 390 Communication device 400 Terminal device 600 Management computer

Claims

1. A travel control system for controlling the automatic travel of an agricultural work vehicle capable of mounting an implement, wherein when the work vehicle passes by an oncoming vehicle on a road outside the field while mounting an implement wider than the work vehicle at the rear, the front part of the work vehicle is closer to the center side of the road and the rear part of the work vehicle is closer to the edge side of the road, and the work vehicle is made to perform a collision avoidance travel for passing by while avoiding a collision between the implement and the oncoming vehicle, the travel control system is provided with a control device for the control device acquires information on the width of the implement and the width of the road, as well as position information of the oncoming vehicle, determines whether or not there is an oncoming vehicle on the travel path of the work vehicle based on the position information of the oncoming vehicle, when it is determined that there is an oncoming vehicle on the travel path, determines the necessity of the collision avoidance travel based on the width of the implement and the width of the road, when it is determined that the collision avoidance travel is necessary, after moving the work vehicle closer to the edge of the road, the front part of the work vehicle is made to be closer to the center side of the road and the rear part of the work vehicle is made to be closer to the edge side of the road, and the work vehicle is made to perform the collision avoidance travel for passing by while avoiding a collision between the implement and the oncoming vehicle, a travel control system.

2. The control device determines the path of the collision avoidance travel so that a part of the implement protrudes outside the road. The travel control system according to claim 1.

3. When the control device determines that there is an oncoming vehicle on the travel path and determines that the collision avoidance travel is unnecessary, after moving the work vehicle closer to the edge of the road, the work vehicle is made to travel straight along the road. The travel control system according to claim 1 or 2.

4. The control device further acquires information on the width of the oncoming vehicle, and further determines the path of the collision avoidance travel based on the width of the oncoming vehicle. The travel control system according to claim 1.

5. When the width of the implement is greater than a value obtained by multiplying the width of the road by a first coefficient of 0.7 or more and 1 or less, the control device determines that the collision avoidance travel is necessary. The travel control system according to claim 1.

6. The control device further acquires information on the width of the oncoming vehicle, and further determines the necessity of the collision avoidance travel based on the width of the oncoming vehicle. The travel control system according to claim 1.

7. The control device determines that the collision avoidance driving is necessary when the sum of the width of the implement and the width of the oncoming vehicle is greater than the value obtained by multiplying the width of the road by a second coefficient of 0.7 or more and 1 or less. The driving control system according to claim 6.

8. When the oncoming vehicle is another work vehicle equipped with another implement and the width of the other implement is greater than the width of the other work vehicle, the control device acquires information indicating the width of the other implement as information indicating the width of the oncoming vehicle. The driving control system according to claim 4.

9. The control device acquires information on the width of the oncoming vehicle and the width of the road respectively from an external device via a network. The driving control system according to claim 4.

10. The control device acquires the position information of the oncoming vehicle based on data output from a sensing device provided in the work vehicle. The driving control system according to claim 1.

11. The control device acquires the position information of the oncoming vehicle via a network and acquires the position information of the work vehicle from a positioning device provided in the work vehicle. The driving control system according to claim 1.

12. Further comprising a storage device for storing an environmental map, The control device, Based on the position information of the work vehicle output from a positioning device provided in the work vehicle and the environmental map, the work vehicle is driven along a target route set on the road outside the field, When it is determined that the oncoming vehicle exists while the work vehicle is being driven along the target route, it is determined whether the collision avoidance driving is necessary. The driving control system according to claim 1.

13. A driving control system according to any one of claims 1 to 12, A driving drive device controlled by the control device, A work vehicle comprising.

14. A driving control method for controlling the automatic driving of an agricultural work vehicle capable of mounting an implement, comprising: When the work vehicle passes by an oncoming vehicle on a road outside the field while mounting an implement wider than the work vehicle at the rear, causing the work vehicle to perform a collision avoidance driving to pass by while avoiding a collision between the implement and the oncoming vehicle. Causing the work vehicle to perform the collision avoidance travel includes controlling the work vehicle so that the front part of the work vehicle approaches the center side of the road and the rear part of the work vehicle approaches the edge side of the road, and the work vehicle passes by the oncoming vehicle. The travel control method further includes: acquiring information on the width of the implement and the width of the road, as well as position information of the oncoming vehicle; determining whether an oncoming vehicle exists on the travel path of the work vehicle based on the position information of the oncoming vehicle; when it is determined that an oncoming vehicle exists on the travel path, determining whether the collision avoidance travel is necessary based on the width of the implement and the width of the road; when it is determined that the collision avoidance travel is necessary, after moving the work vehicle closer to the edge of the road, making the front part of the work vehicle approach the center side of the road and the rear part of the work vehicle approach the edge side of the road, and causing the work vehicle to perform the collision avoidance travel of passing by while avoiding a collision between the implement and the oncoming vehicle; A travel control method including the above.

Images