WO2019054057A1

WO2019054057A1 - Autonomous travel system for work vehicle

Info

Publication number: WO2019054057A1
Application number: PCT/JP2018/027855
Authority: WO
Inventors: 優飛兒玉
Original assignee: ヤンマー株式会社
Priority date: 2017-09-14
Filing date: 2018-07-25
Publication date: 2019-03-21

Abstract

[Problem] To inhibit decline in work precision caused by travel offset arising from a steering angle error. [Solution] Provided is an autonomous travel system for a work vehicle comprising: a steering angle setting unit 16E for setting a target steering angle θs; and a steering angle sensor 18 for sensing a steering angle. The steering angle setting unit 16E comprises: a bearing angle deviation computation means 16Ea for computing a bearing angle deviation; a steering angle error detection means 16Eb for detecting a steering angle error; and a steering angle computation means 16Ec for computing the target steering angle θs from the bearing angle deviation and steering angle error. The bearing angle deviation computation means 16Ea sets a target point on a target path which is at a prescribed distance from the current position in the direction of progress during autonomous travel, generates a target bearing line from the present position to the target point, and computes the angle formed by the present bearing and the target bearing line as the bearing angle deviation.

Description

Autonomous traveling system for work vehicle

The present invention relates to an autonomous traveling system for work vehicles that can be used for unmanned work vehicles such as tractors, ride rice planters, combine harvesters, ride mowers, wheel loaders, snow removal vehicles, and unmanned work vehicles such as unmanned grass mowers. More specifically, a storage unit for storing a target route generated in advance, a positioning unit for measuring a current position and a current direction of the vehicle, and automatically steering steered wheels so that the vehicle autonomously travels the target route And an autonomous steering system for a work vehicle having an automatic steering unit.

In an autonomous traveling system for a work vehicle as described above, a geomagnetic bearing sensor for detecting the direction of the vehicle, a GPS receiver for recognizing the current position of the vehicle, and a steering angle sensor for detecting the steering angle of the front wheels During autonomous traveling of the work vehicle on the straight line target route, the central portion, which is the central position between the front wheels on the front side of the vehicle body, and the GPS position measurement point, which is the antenna installation position of the GPS receiver on the vehicle rear side, When the front wheel is steered at an arbitrary steering angle while being laterally separated from the straight target path by a first distance or a second distance, a perpendicular to the straight target path from the central portion on the front side of the vehicle body The target point is set on the straight target path ahead a third distance from the point of intersection of the target and the straight target path, and between the straight line connecting the central portion and the target point and a straight line parallel to the straight target path passing through the central portion Previous target heading The previous target heading = Arctan (first distance / third distance) is calculated, and the target steering angle (target steering angle = heading + steering angle + target heading) for the heading of the vehicle with respect to the straight target path, steering angle and target heading Calculate In addition, a back target point is set on a straight target route that is a fourth distance ahead of the intersection between the perpendicular to the straight target route from the GPS position measurement point and the straight target route, and a straight line connecting the GPS position measurement point and the back target point And a target azimuth (target azimuth = Arctan (second distance / fourth distance)) between a straight line parallel to the straight line target path passing the GPS position measurement point. Then, from the steering control value based on the target steering angle of the front wheel and the proportional and integral value of PI control based on the target direction of the GPS position measurement point, the command value for front wheel steering not including the error of the geomagnetic direction sensor is calculated. By configuring the steering angle of the front wheels on the basis of the command value and the output of the steering angle sensor so that the steering angle of the front wheels matches the command value, the host vehicle can travel autonomously along the target route. There are some examples (see, for example, Patent Document 1).

JP 2002-358122 A

In the configuration described in Patent Document 1, a command value for front wheel steering is calculated from a steering control value based on a target steering angle of a front wheel and a proportional and integral value of PI control based on a target direction of a GPS position measurement point. This complicates the operation and increases the load required for the operation.
Moreover, in the configuration described in Patent Document 1, the third distance for setting the target point described above is switched by the magnitude change of the first distance (left and right separation distance) in the lateral direction from the linear target route of the GPS position measurement point. Therefore, in setting the target steering angle, it is necessary to consider the lateral deviation in addition to the azimuthal deviation, which further increases the load required for the calculation.

Further, in the configuration described in Patent Document 1, when automatic steering of the front wheels is performed, a steering angle error caused by an individual difference of the steering angle sensor is not taken into consideration, as shown in FIGS. 8 and 20. When the work vehicle 1 travels autonomously in the straight working route portion P1 of the target route P, even if the target steering angle of the steered wheels is set to the straight target steering angle, the steering angle error of the steered wheels The actual steering angle deviates from the target steering angle for going straight, and the work vehicle 1 is gradually offset in an oblique direction from the straight working path portion P1 according to the amount of deviation at this time. After that, even if the target steering angle of the steered wheels is changed to the target steering angle for returning the work vehicle 1 to the straight path portion P1 based on the offset at this time, the change amount of the target steering angle at this time is Since the work vehicle 1 is offset with the angular error, the work vehicle 1 travels with a constant travel offset amount So for the straight work path portion P1. As a result, the working accuracy is reduced due to the traveling offset.

In view of this situation, a main problem of the present invention is to provide an autonomous travel system for a work vehicle which can suppress a decrease in work accuracy due to a travel offset caused by a steering angle error.

The first feature of the present invention is
A storage unit for storing a target route generated in advance, a positioning unit for measuring a current position and a current direction of the vehicle, and an automatic steering unit for automatically steering steered wheels so that the vehicle autonomously travels the target route Equipped with
The automatic steering unit has a steering angle setting unit that sets a target steering angle of the steered wheels, and a steering angle sensor that detects a steered angle of the steered wheels.
The steering angle setting unit comprises azimuth angle deviation calculation means for calculating an azimuth angle deviation, steering angle error detection means for detecting a steering angle error during autonomous traveling, the target from the azimuth angle deviation and the steering angle error. And steering angle calculation means for calculating a steering angle,
The azimuth deviation calculation means is a target point setting process for setting a target point on the target route with a predetermined distance from the current position to the traveling direction side during autonomous traveling, and a target from the current position to the target point A point of performing line generation processing for generating an azimuth line and azimuth deviation calculation processing for calculating an angle formed by the current azimuth and the target azimuth line as the azimuth deviation.

According to this configuration, the azimuth deviation calculation means performs the target point setting process, the line generation process, and the azimuth deviation calculation process described above, whereby the azimuth angle between the azimuth of the target azimuth line and the current azimuth of the vehicle is obtained. Deviation can be calculated easily. Then, the steering angle calculation means can calculate a suitable target steering angle in consideration of the steering angle error by adding the steering angle error detected by the steering angle error detection means to the azimuth angle deviation.
Thus, by performing the automatic steering of the steered wheels based on the target steering angle, it is possible to reduce the traveling offset amount with respect to the target route of the vehicle during autonomous traveling due to the steering angle error.
As a result, it is possible to suppress a decrease in the working accuracy due to the travel offset caused by the steering angle error while reducing the calculation load required to calculate the target steering angle.

The second feature of the present invention is
The target route is divided into a plurality of types of route parts according to the traveling mode of the vehicle,
The storage unit stores a plurality of the predetermined distances set to different lengths according to the type of the path unit,
The azimuth deviation calculation means automatically changes the predetermined distance in accordance with the type of the route section on which the vehicle travels autonomously.

According to this configuration, it is possible to eliminate the trouble of the user manually changing the predetermined distance in accordance with the type of the route section on which the work vehicle travels autonomously. In addition, it is possible to prevent the decrease in the calculation accuracy of the azimuth deviation due to the user mistaking the predetermined distance or forgetting to change the predetermined distance.

The third characterizing feature of the present invention is
The target route is divided into a plurality of types of route parts according to the traveling mode of the vehicle,
The azimuth deviation calculation means is to set the target point on the extension of the current route portion until the current position is switched from the current route portion to the next route portion of a different type.

According to this configuration, for example, while the vehicle is autonomously traveling on the straight path portion, it is possible to set a target point suitable for autonomous traveling on the straight path portion, and from this target point on the straight path portion A target steering angle suitable for autonomous traveling of the vehicle can be calculated. Further, for example, while the vehicle is autonomously traveling in the turning route portion, it is possible to set a target point suitable for autonomous traveling in the turning route portion, and from this target point to autonomous traveling in the turning route portion A suitable target steering angle can be calculated. As a result, it is possible to improve the traveling accuracy when the vehicle autonomously travels on the target route.

The fourth characterizing feature of the present invention is
A storage unit for storing a target route generated in advance, a positioning unit for measuring a current position and a current direction of the vehicle, and an automatic steering unit for automatically steering steered wheels so that the vehicle autonomously travels the target route Equipped with
The automatic steering unit has a steering angle setting unit that sets a target steering angle of the steered wheels, and a steering angle sensor that detects a steered angle of the steered wheels.
The steering angle setting unit corrects the target steering angle with a steering angle error, a steering angle calculation unit that calculates the target steering angle, a steering angle error detection unit that detects a steering angle error during autonomous traveling, and And a steering angle correction means,
The steering angle error detection means sets a gaze point setting process on the target route with a predetermined distance from the current position to the traveling direction side during autonomous traveling, and a line extending from the current position to the gaze point A line segment generation process for generating a minute, and a steering angle error calculation process for calculating an angle formed by the target route and the line segment as the steering angle error,
The steering angle correction means performs correction processing for adding the steering angle error obtained by the steering angle error calculation processing to the target steering angle.

According to this configuration, the steering angle error detection means can easily detect the steering angle error at the time of autonomous traveling by performing the gaze point setting process, the line segment generation process, and the steering angle error calculation process described above. it can. Then, the steering angle correction means can obtain the target steering angle in which the steering angle error is taken into consideration by performing the above-described correction processing, and performs automatic steering of the steered wheels based on the corrected target steering angle. As a result, it is possible to reduce the travel offset amount with respect to the target route of the vehicle at the time of autonomous travel due to the steering angle error.
As a result, it is possible to suppress a decrease in the working accuracy due to the travel offset caused by the steering angle error while reducing the calculation load required to calculate the steering angle error.

The fifth characterizing feature of the present invention is
The steering angle error detection means determines whether or not a predetermined condition for allowing detection of the steering angle error is satisfied, and the steering angle error is detected until the predetermined condition is satisfied. The point is to perform a detection prohibition process to prohibit the detection.

According to this configuration, the steering angle error detection means detects the initial deviation or the like occurring immediately after the work vehicle starts autonomous traveling as the steering angle error by the steering angle error detection means, so that the detection accuracy of the steering angle error by the steering angle error detection means Can be prevented.
As a result, the target steering angle is corrected with a steering angle error having a low detection accuracy, and the automatic steering of the steered wheels is performed on the basis of the corrected target steering angle. It is possible to avoid the occurrence of the problem that the travel offset amount to the route is less likely to decrease.

The sixth characterizing feature of the present invention is
In the detection condition determination process, the steering angle error detection means determines that the predetermined condition is satisfied when the vehicle travels a certain distance required from the start of the autonomous traveling to the settling of the autonomous traveling. It is in.

According to this configuration, detection of the steering angle error is prohibited by the detection prohibiting process from the start of the autonomous traveling of the vehicle to the time when the vehicle travels a certain distance.
Thus, the steering angle error is detected and the target steering angle is corrected based on the detected steering angle error even during the period from when the vehicle starts autonomous traveling to when the autonomous traveling settles. The target path of the working vehicle at the time of autonomous traveling due to the fact that the detection accuracy of the angular error is reduced and the automatic steering of the steered wheels is performed based on the target steering angle corrected by the low steering angle error of this detection accuracy. It is possible to avoid the occurrence of the problem that the traveling offset amount for the vehicle becomes difficult to decrease.

The seventh characterizing feature of the present invention is
The steering angle error detection means performs the detection of the steering angle error a plurality of times until the vehicle travels the set distance for detecting the steering angle error, and the average of the steering angle errors for a plurality of times is detected. A point is that averaging is performed to obtain a value and use the average value as a steering angle error for correction processing.

According to this configuration, the detection accuracy of the steering angle error by the steering angle error detection means can be enhanced by the above-described averaging process. Then, the steering wheel is automatically steered on the basis of the target steering angle corrected with the steering angle error having a high detection accuracy, thereby more reliably reducing the traveling offset amount with respect to the target route of the vehicle during autonomous traveling. be able to. As a result, it is possible to more effectively suppress the decrease in work accuracy due to the traveling offset.

The eighth characterizing feature of the present invention is
The steering angle error detection means redetects the steering angle error and updates the steering angle error each time the vehicle travels a set distance for steering angle error redetection during autonomous traveling.

According to this configuration, the steering angle error detection means can increase the detection accuracy of the steering angle error each time the steering angle error is updated by the updating process. Then, the automatic steering of the steered wheels is performed based on the target steering angle corrected with the steering angle error at which the detection accuracy is enhanced for each update, and as the autonomous travel distance of the own vehicle becomes longer, The travel offset amount with respect to the target route of the own vehicle can be reduced, and a reduction in work accuracy due to the travel offset can be more effectively suppressed.

The figure which shows schematic structure of the autonomous travel system for work vehicles in a 1st embodiment Block diagram showing a schematic configuration of an autonomous travel system for a work vehicle in the first embodiment A diagram showing an example of a target route generated for autonomous traveling of a work vehicle in a field in the first embodiment Explanatory drawing about calculation of the azimuth deviation in the state which the working vehicle in 1st Embodiment is autonomously traveling on a straight work path part Explanatory drawing about the calculation of the azimuth deviation in the state in which the work vehicle in the first embodiment travels autonomously on the backward straight traveling route portion Explanatory drawing about calculation of the azimuth deviation in the state which the working vehicle in 1st Embodiment is autonomously traveling in the turning path part Detailed explanatory drawing about calculation of azimuth deviation in the state where the work vehicle in the first embodiment is autonomously traveling in the turning path portion An explanatory view showing a state where the working vehicle travels offset with respect to a target route due to a steering angle error during autonomous traveling of the working vehicle in the first embodiment Explanatory drawing about detection of the steering angle error in 1st Embodiment Flow chart on detection of steering angle error in the first embodiment Explanatory drawing about the setting of the target point in 1st Embodiment The figure which shows schematic structure of the autonomous travel system for work vehicles in a 2nd embodiment Block diagram showing a schematic configuration of an autonomous traveling system for a work vehicle in a second embodiment The figure which shows an example of the target path | route produced | generated in order that a work vehicle autonomously travels in the field in 2nd Embodiment. Explanatory drawing about calculation of the azimuth deviation in the state which the working vehicle in 2nd Embodiment is autonomously traveling on a straight work path part Explanatory drawing about calculation of the azimuth deviation in the state which the working vehicle in 2nd Embodiment is autonomously traveling on reverse going straight path part Explanatory drawing about calculation of the azimuth deviation in the state which the working vehicle in 2nd Embodiment is autonomously traveling in the turning path part Detailed explanatory drawing about calculation of azimuth deviation in a state where a work vehicle in the second embodiment is autonomously traveling in a turning path portion Explanatory drawing about the setting of the target point in 2nd Embodiment An explanatory view showing a state where the working vehicle travels offset with respect to a target route due to a steering angle error during autonomous traveling of the working vehicle in the second embodiment Explanatory drawing about detection of the steering angle error in 2nd Embodiment Flow chart on detection of steering angle error in the second embodiment

First Embodiment
A first embodiment in which an autonomous traveling system for a work vehicle according to the present invention is applied to a tractor which is an example of a work vehicle will be described based on the drawings.
The autonomous traveling system for work vehicles according to the present invention is a work vehicle other than a tractor, such as a riding rice planter, a combine, a riding grass mower, a wheel loader, a snow removal vehicle, and an unmanned grass mower etc. It can be applied to vehicles.

As shown in FIGS. 1 and 2, the autonomous traveling system for a work vehicle illustrated in the first embodiment is set to be communicable with the autonomous traveling unit 2 mounted on the tractor 1 and the autonomous traveling unit 2. Mobile communication terminal 3 and the like. As the mobile communication terminal 3, a tablet-type personal computer, a smart phone, or the like having a touch-operable liquid crystal panel 4 or the like can be adopted.

As shown in FIG. 1, the tractor 1 is connected to the rotary tillage specification by the rotary tilling device 6, which is an example of the working device, connected to the rear portion via the three-point link mechanism 5 so as to be movable up and down. It is configured.
In addition, it can replace with the rotary tilling apparatus 6, and can connect work apparatuses, such as a plow, a sowing apparatus, a scattering apparatus, to the rear part of the tractor 1. FIG.

As shown in FIGS. 1 and 2, the tractor 1 includes left and right front wheels 7 functioning as drivable steerable wheels, left and right drivable rear wheels 8, a cabin 9 forming a riding type driving unit, and a common rail system. An electronically controlled diesel engine (hereinafter referred to as the engine) 10, an electronically controlled transmission 11 for shifting power from the engine 10, a full hydraulic power steering mechanism 12 for steering the left and right front wheels 7, The left and right side brakes (not shown) that brake the rear wheel 8, the electronically controlled brake operation mechanism 13 that enables hydraulic operation of the left and right side brakes, and the working clutch that interrupts transmission to the rotary cultivator 6 (Not shown), an electronically controlled clutch operating mechanism 14 which enables hydraulic operation of the working clutch, and an electrohydraulic controlled lifting drive for lifting and lowering the rotary cultivator 6 A mechanism 15, an on-vehicle electronic control unit (hereinafter referred to as an on-vehicle ECU) 16 having various control programs related to autonomous traveling of the vehicle (tractor) 1 etc., a vehicle speed sensor 17 for detecting the vehicle speed of the vehicle 1, A steering angle sensor 18 for detecting a steering angle, and a positioning unit 19 for measuring a current position and a current direction of the vehicle 1 are provided.
The engine 10 may be an electronically controlled gasoline engine equipped with an electronic governor. For the transmission 11, a hydromechanical continuously variable transmission (HMT), a hydrostatic continuously variable transmission (HST), a belt type continuously variable transmission, or the like can be adopted. The power steering mechanism 12 may be, for example, an electric power steering mechanism 12 provided with an electric motor.

As shown in FIG. 1, a steering wheel 20 and a seat 21 for a user are provided inside the cabin 9 to enable manual steering of the left and right front wheels 7 via the power steering mechanism 12. Also, although not shown, a shift lever that enables manual operation of the transmission 11, a left and right brake pedal that enables manual operation of the left and right side brakes, and a manual lifting operation of the rotary tilling device 6 Lift levers, etc. are provided.

As shown in FIG. 2, the on-vehicle ECU 16 controls a shift control unit 16A that controls the operation of the transmission 11, a brake control unit 16B that controls the operation of the left and right side brakes, and a working device control that controls the operation of the rotary tilling device 6. 16C, a non-volatile vehicle storage unit 16D for storing a previously generated target route P for autonomous traveling, etc., and the target steering angle θs of the front wheels 7 on both sides during autonomous traveling, and output to the power steering mechanism 12 Steering angle setting unit 16E, and the like.

As shown in FIGS. 1 to 3, the positioning unit 19 uses the GPS (Global Positioning System), which is an example of the Global Navigation Satellite System (GNSS), and the current position p1 of the vehicle 1 An inertial measurement unit (IMU: Inertial Measurement Unit) that measures the attitude, orientation, etc. of the vehicle 1 with a satellite navigation device 22 that measures the current orientation θ1, a three-axis gyroscope, three-direction acceleration sensors, etc. ) 23, etc. are provided. Positioning methods using GPS include DGPS (Differential GPS: relative positioning method), RTK-GPS (Real Time Kinematic GPS: interference positioning method), etc. In the first embodiment, it is suitable for positioning of a mobile object. RTK-GPS is adopted. Therefore, a reference station 24 that enables positioning by RTK-GPS is installed at a known position around the farmland.

Each of the tractor 1 and the reference station 24 can wirelessly communicate various data including GPS data between the tractor 1 and the reference station 24 and

GPS antennas

26 and 27 for receiving radio waves transmitted from the GPS satellite 25.

Communication modules

28, 29, etc. are provided. Thereby, the satellite navigation device 22 receives the positioning data obtained by the GPS antenna 26 on the tractor side receiving radio waves from the GPS satellites 25 and the GPS antenna 27 on the base station side receives radio waves from the GPS satellites 25. The current position p1 and the current direction θ1 of the vehicle 1 can be measured with high accuracy based on the obtained positioning data. In addition, the positioning unit 19 includes the satellite navigation device 22 and the inertial measurement device 23 so that the current position p1 of the vehicle 1, the current direction θ1, and the attitude angle (yaw angle, roll angle, pitch angle) can be made with high accuracy. It can be measured.

As shown in FIGS. 2 to 3, the mobile communication terminal 3 includes a terminal electronic control unit (hereinafter referred to as a terminal ECU) 30 having various control programs for controlling the operation of the liquid crystal panel 4 etc. And a communication module 31 that enables wireless communication of various data including positioning data with the communication module 28 of FIG. The terminal ECU 30 is a non-volatile terminal storing a target route generation unit 30A that generates a target route P for autonomous traveling, and various input data input by the user, the target route P generated by the target route generation unit 30A, and the like. A storage unit 30B and the like are included.

As shown in FIGS. 1 to 3, the target route generation unit 30A follows the input guidance for target route generation displayed on the liquid crystal panel 4 to obtain vehicle data such as the type and model of the work vehicle and the work device, and When the target field position and the like are input by the user, it is determined whether or not the corresponding target route P is stored in the terminal storage unit 30B based on the input vehicle data, the field position, and the like. When the corresponding target route P is stored, the target route P is read from the terminal storage unit 30 B and displayed on the liquid crystal panel 4. When the corresponding target route P is not stored, the liquid crystal panel 4 displays an execution guidance of positioning data acquisition travel for obtaining positioning data necessary for generation of the target route P, and the user performs positioning data acquisition travel. Let Then, based on the positioning data and the like obtained by wireless communication with the tractor 1 during this positioning data acquisition traveling, the field data such as the section and the shape of the work field and the like are acquired, and the acquired field data and vehicle data The target route P suitable for working on the field to be worked with this tractor 1 is generated on the basis of the minimum turning radius, the working width, etc. included in. Then, the generated target route P is displayed on the liquid crystal panel 4 and stored in the terminal storage unit 30B as route data associated with the vehicle data and the field data. The route data includes an azimuth angle θp of the target route P, a target engine rotation speed, a target vehicle speed, and the like set according to the traveling mode of the tractor 1 on the target route P and the like.

As shown in FIG. 3, in the first embodiment, a field divided into a rectangular shape is illustrated as a field to be worked. In addition, as a target route P suitable for the rectangular field, a plurality of straight movement work path portions P1 having the same straight movement distance and arranged in parallel with a predetermined distance corresponding to the work width, and adjacent straight movement A reciprocating traveling route is illustrated, which includes a plurality of direction change path portions P2 extending from the end point P1e of the working path portion P1 to the start point P1s and causes the tractor 1 to reciprocate from the start point Ps of the target path P to the end point Pe. ing. Of the plurality of rectilinear work path portions P1, the odd-numbered row is the forward path portion, and the even-numbered row is the return path portion. The plurality of direction change path portions P2 are a first turning path portion P3 for turning the tractor 1 by 90 degrees from the end point P1e of the straight working path portion P1 toward the next straight working path portion, and a first turning path portion P3. A straight forward path P4 for moving the tractor 1 straight backward from the turning end point P3e toward the previous straight working path, and a starting point of the next straight working path P1 from a backward finish point P4e of the backward straight path P4 It is divided by the 2nd turning course part P5 which turns the tractor 1 90 degrees toward the point P1s.
That is, the target route P is divided into a plurality of types of route portions P1 to P5 in accordance with the traveling mode of the vehicle 1.
The target path P shown in FIG. 3 is merely an example, and the target path P is, for example, a plurality of direction change path portions P2, and from the end point P1e of the straight work path portion P1 to the start end of the next straight work path portion P1. It may be generated so as to include a U-turn path portion that turns the tractor 1 180 degrees toward the point P1s.

As shown in FIGS. 2 to 3, in the state where the target route P is confirmed and displayed on the liquid crystal panel 4, the terminal ECU 30 instructs execution of autonomous traveling by the operation of the liquid crystal panel 4 by the user. The target route P being displayed together with the execution command is transmitted to the in-vehicle ECU 16 via the

communication modules

31 and 28.
With regard to the transmission of the target route P, the entire target route P may be transmitted at once from the terminal ECU 30 to the on-vehicle ECU 16 at a stage before the tractor 1 starts autonomous traveling. Also, for example, in the stage before the target route P is divided into a plurality of route portions for each predetermined distance with a small amount of data and the tractor 1 starts autonomous traveling, only the initial route portion of the target route P is the terminal ECU 30 After the start of autonomous traveling, each time the tractor 1 reaches the route acquisition point set according to the amount of data, only the route part corresponding to that point is transmitted from the terminal ECU 30 to the vehicle ECU 16. It may be sent to the

When the on-board ECU 16 receives the execution command for autonomous traveling from the terminal ECU 30 and the target route P, the on-vehicle storage unit 16D stores the received target route P in the on-vehicle storage unit 16D to check the data amount. The autonomous traveling control for causing the vehicle to travel autonomously is started based on the target route P and the like stored in the on-vehicle storage unit 16D.

For autonomous traveling control, automatic shift control for automatically controlling the operation of the transmission 11, automatic braking control for automatically controlling the operation of the brake operating mechanism 13, automatic steering control for automatically steering the left and right front wheels 7, and a rotary tilling device Automatic control for work to automatically control the operation of 6, etc. are included.
In the automatic shift control, the shift control unit 16A controls the traveling mode of the tractor 1 on the target route P based on the target route P including the target vehicle speed described above, the output of the positioning unit 19, and the output of the vehicle speed sensor 17. The operation of the transmission 11 is automatically controlled so that the target vehicle speed set accordingly is obtained as the vehicle speed of the vehicle 1.
In automatic braking control, the braking control unit 16B properly sets the left and right side brakes on the left and right side brakes in the braking area included in the target path P based on the target path P and the output of the positioning unit 19. The operation of the brake operation mechanism 13 is automatically controlled to brake.
In automatic steering control, the steering angle setting unit 16E sets the target steering angles θs of the left and right front wheels 7 based on the target path P and the output of the positioning unit 19 so that the vehicle 1 autonomously travels on the target path P. The power steering mechanism 12 outputs the target steering angle θs which has been obtained and set, and which has been set. Then, the power steering mechanism 12 automatically steers the left and right front wheels 7 based on the target steering angle θs and the output of the steering angle sensor 18 so that the target steering angle θs can be obtained as the steering angle of the left and right front wheels 7.
In automatic control for work, the rotary tilling apparatus is operated as the vehicle 1 reaches the start point P1s of the straight work path portion P1 based on the target path P and the output of the positioning unit 19 in the working device control unit 16C. 6. The clutch operating mechanism 14 and the elevation drive mechanism 15 are set so that the tilling by the rotary tilling device 6 is stopped when the tilling by 6 is started and the own vehicle 1 reaches the end point P1e of the straight working path portion P1. Automatically control the operation of

That is, in the tractor 1, the transmission 11, the power steering mechanism 12, the brake operation mechanism 13, the clutch operation mechanism 14, the elevation drive mechanism 15, the on-vehicle ECU 16, the vehicle speed sensor 17, the steering angle sensor 18, the positioning unit 19, The autonomous traveling unit 2 is configured by the communication module 28 and the like. The power steering mechanism 12, the on-vehicle ECU 16, and the steering angle sensor 18 constitute an automatic steering unit 32 for automatically steering the left and right front wheels 7 so that the vehicle 1 autonomously travels on the target path P.

If setting of the target steering angle θs is described in detail, as shown in FIGS. 2 to 7, the steering angle setting unit 16E calculates azimuth angle deviation calculating means 16Ea for calculating the azimuth angle deviation θd, and steering angle error θe during autonomous traveling. The steering angle error detection unit 16Eb detects the steering angle error, and the steering angle calculation unit 16Ec calculates the target steering angle θs from the azimuth angle deviation θd and the steering angle error θe.

The azimuth deviation calculation means 16Ea sets a target point p2 on a target route with a predetermined distance D1 in the direction of travel from the current position p1 of the vehicle 1 during autonomous traveling, and Line generation processing for generating a target azimuth line L1 from the current position p1 to the target point p2, and azimuth deviation calculation processing for calculating an angle formed by the current azimuth θ1 of the vehicle 1 and the target azimuth line L1 as the azimuth deviation θd I do.

In the azimuth deviation calculation process, as shown in FIGS. 4 to 5, if the current travel path of the vehicle 1 is the straight work path portion P1 or the backward straight path portion P4, as shown in FIGS. If the direction from the current position p1 of the vehicle 1 to the target point p2 (the azimuth of the target azimuth line L1) is the target azimuth angle θ2, and the angle between the target route P and the target azimuth line L1 is the traveling correction angle θc , The target azimuth angle θ2 at the straight working path portion P1 is
Target azimuth angle θ2 = azimuth angle θp1 of straight working path portion P1 + traveling correction angle θc
The target azimuth angle θ2 at the rear straight path portion P4 is
Target azimuth angle θ2 = azimuth angle θp4 of the rear straight path portion P4 + traveling correction angle θc
It becomes.
Here, the azimuth angle θp1 of the straight working path portion P1 and the azimuth angle θp4 of the backward straight path portion P4 are known at the stage of generating the target path P, but when these are calculated, the straight working path portion P1 is Assuming that the E component (x component) of the vector V1 from the start point P1s to the end point P1e is V1e and the N component (y component) of the vector V1 is V1n,
Azimuth angle θp1 = atan2 (V1e, V1n) of the straight working path portion P1
It becomes. Further, assuming that the E component (x component) of the vector V4 from the start position to the end position of the straight rear path portion P4 is V4e and the N component (y component) of the vector V4 is V4n,
Azimuth angle θp4 = atan2 (V4e, V4n) of the rear straight path portion P4
It becomes. Then, assuming that the travel correction angle θc is a lateral deviation from the travel route of the vehicle 1 on the NED coordinates as D2, the predetermined distance for setting the target point is D1,
Travel correction angle θc = asin (lateral deviation D2 / predetermined distance D1)
Thus, the target azimuth θ2 can be determined, and the azimuth deviation θd can be obtained from the difference between the determined target azimuth θ2 and the current azimuth θ1 of the vehicle 1 measured by the positioning unit 19.
On the other hand, as shown in FIGS. 6 to 7, if the current travel route of the vehicle 1 is the first turning path portion P3 or the second turning path portion P5, the turning centers pt of the respective turning path portions P3, P5. Assuming that the angle between the vector Vv and the N axis from the vehicle 1 to the N axis is θv, the azimuth deviation θd is obtained from the aforementioned angle θv, the current direction θ1 of the vehicle 1 and the travel correction angle θc
Azimuth deviation θd = angle θv + SignTrn × 90−present azimuth θ1 + SignTrn × (90−travel correction angle θc)
It can be determined by
Here, degrees are used for all units in this formula, and "90" in the formula indicates 90 degrees. Further, with regard to “Sign Trn”, it is “1” when the turning direction is the clockwise direction, and “−1” when the turning direction is the counterclockwise direction. The travel correction angle θc in the above equation is a predetermined distance D1 for setting a target point, a distance D3 from the turning center pt of the turning path portions P3 and P5 to the vehicle 1, and turning of the turning path portions P3 and P5. From the radius R,
Travel correction angle θc = acos ((D3 ^ 2 + D1 ^ 2-R ^ 2) / (2 × D3 × D1)
The distance D3 from the turning center pt of the turning path portions P3 and P5 to the vehicle 1 in this equation is the turning radius R of the turning path portions P3 and P5, and the distance D3 of the vehicle 1 on the NED coordinates. From the lateral deviation D2 from the turning path parts P3 and P5,
Distance D3 = turning radius R + lateral deviation D2
It can be determined by

By the way, since the azimuth deviation θd calculated by the azimuth deviation calculation means 16Ea is the difference between the target azimuth θ2 and the current azimuth θ1 of the vehicle 1 as described above, it can also be used as the target steering angle θs. In this case, in the working vehicle such as the tractor 1, since the steering angle error θe caused by the individual difference of the steering angle sensor 18 is included in the steering system, the steering angle error during autonomous traveling is considered. Due to θe, as shown in FIG. 8, the work vehicle travels in a state where a certain travel offset amount So with respect to the target route P is left. As a result, the working accuracy is reduced due to the traveling offset.

Therefore, in order to suppress the decrease in work accuracy caused by the travel offset, the steering angle setting unit 16E has the steering angle error detection unit 16Eb and the steering angle calculation unit 16Ec as described above.
As shown in FIGS. 9 to 10, the steering angle error detection means 16Eb moves from the current position p1 of the vehicle 1 to the traveling direction during straight traveling by autonomous traveling of the vehicle 1 in the straight operation route portion P1 of the target route P. A fixation point setting process (step # 3) for setting a fixation point p3 on a target route with a fixed distance D4 (front side) and a line for generating a line L2 from the current position of the vehicle 1 to the fixation point p3 A minute generation process (step # 4) and a steering angle error calculation process (step # 5) for calculating an angle formed by the target path P and the line segment L2 as the steering angle error θe are performed. Then, in the steering angle error calculation process, assuming that the lateral deviation from the straight working path portion P1 of the vehicle 1 on the NED coordinates is D5, the constant distance for setting the fixation point is D4, The angular error θe
Steering angle error θe = asin (lateral deviation D5 / fixed distance D4)
It can be determined by
The steering angle calculation means 16Ec calculates a target steering angle θs by adding the steering angle error θe obtained by the steering angle error calculation process to the azimuth angle deviation θd obtained by the azimuth angle deviation calculation process described above. Do the processing.
As a result, it is possible to calculate the target steering angle θs to a suitable value in which the steering angle error θe is taken into consideration, and outputting the target steering angle θs to the power steering mechanism 12 The travel offset amount So with respect to the target route P can be reduced. As a result, it is possible to suppress a decrease in work accuracy due to the traveling offset.
That is, the target steering angle θs can be calculated to a suitable value in consideration of the steering angle error θe while reducing the calculation load applied to the steering angle setting unit 16E in calculating the target steering angle θs.

As shown in FIGS. 4 to 7, in the on-vehicle storage unit 16D, a plurality of predetermined distances D1a to D1c for setting target points set to different lengths according to the types of the respective route parts P1 to P5 in the target route P. Is stored. The azimuth deviation calculation means 16Ea automatically changes the predetermined distance D1 for target point setting in the target point setting process according to the type of each of the route parts P1 to P5 on which the vehicle 1 travels autonomously on the target route P.
As a result, it is possible to eliminate the trouble of the user manually changing the predetermined distance D1 in accordance with the types of the route portions P1 to P5 on which the tractor 1 travels autonomously. In addition, it is possible to prevent the decrease in the calculation accuracy of the azimuth deviation θd caused by the user mistaking the predetermined distance D1 or forgetting to change the predetermined distance D1.

With respect to the predetermined distance D1 for setting the target point, the azimuth deviation calculation means 16Ea, as shown in FIG. 4, moves the predetermined distance D1 to the vehicle 1 when the current position p1 of the vehicle 1 is the straight work path part P1. Is changed to a first predetermined distance D1a suitable for autonomous traveling on the straight working path portion P1.
When the current position p1 of the vehicle 1 is the backward straight path portion P4 as shown in FIG. 5, the azimuth deviation calculation means 16Ea autonomously travels the predetermined distance D1 in the backward straight path portion P4. The second predetermined distance D1b suitable for The second predetermined distance D1b is a rear steering that steers the left and right front wheels 7 on the rear side in the traveling direction and corrects the traveling direction when the vehicle 1 corrects the traveling direction in autonomous traveling on the rear straight traveling path portion P4. The distance is set to be longer than the first predetermined distance D1a in consideration of an increase in the amount of shake.
When the current position p1 of the vehicle 1 is the first turning path portion P3 or the second turning path portion P5, as shown in FIGS. Is changed to a third predetermined distance D1c suitable for autonomous traveling on the first turning path portion P3 or the second turning path portion P5. The third predetermined distance D1c is a first predetermined distance in consideration of the fact that the vehicle 1 is easily separated from the turning path portions P3 and P5 during autonomous traveling on the first turning path portion P3 or the second turning path portion P5. The distance is set to be shorter than the predetermined distance D1a and the second predetermined distance D1b.

As shown in FIG. 11, the azimuth deviation calculation means 16Ea is the next path part (for example, the first turning path part) of which the current position p1 of the vehicle 1 is different from the current path part (for example, straight working path part P1). Until switching to P3), the target point p2 is set on the extension of the current path part.
Thus, for example, while the vehicle 1 travels autonomously in the straight operation path portion P1, it is possible to set a target point p2 suitable for autonomous traveling in the straight operation path portion P1, and from the target point p2 It is possible to calculate the target steering angle θs suitable for autonomous traveling on the straight working path portion P1. Further, for example, while the vehicle 1 travels autonomously in the first turning path portion P3, it is possible to set a target point p2 suitable for autonomous traveling in the first turning path portion P3, and this target point p2 From the above, it is possible to calculate the target steering angle θs suitable for autonomous traveling on the first turning path portion P3. As a result, it is possible to improve the traveling accuracy when the vehicle 1 travels autonomously on the target route P.

As shown in FIGS. 3 and 9 to 10, the steering angle error detection means 16Eb determines whether or not a predetermined condition for allowing detection of the steering angle error θe is satisfied (step # 1). And, the detection prohibiting process (step # 2) of prohibiting the detection of the steering angle error θe is performed until the predetermined condition is satisfied.
In the first embodiment, as a predetermined condition, it is set whether or not a predetermined distance La necessary for the autonomous traveling to settle after the autonomous vehicle 1 has started the autonomous traveling on the straight operation route portion P1 is run. ing. Then, in the detection condition determination process, the steering angle error detection means 16Eb assumes that the predetermined condition is satisfied when the own vehicle 1 has run a predetermined distance La after starting autonomous traveling on the straight work path portion P1. It is configured to make a determination, whereby the detection prohibiting process is performed by the detection prohibiting process from when the vehicle 1 starts autonomous traveling on the straight working path portion P1 until it runs through the predetermined distance La. Detection is prohibited.
As a result, detection of the steering angle error θe and target steering based on the detected steering angle error θe also from when the vehicle 1 starts autonomous traveling on the straight working path portion P1 until the autonomous traveling is settled. The calculation of the angle θs reduces the detection accuracy of the steering angle error θe, and the target steering angle θs is calculated based on the steering angle error θe having a low detection accuracy and is output to the power steering mechanism 12 As a result, it is possible to avoid the occurrence of the inconvenience that the traveling offset amount So with respect to the target route P of the vehicle 1 at the time of autonomous traveling hardly decreases.

As shown in FIGS. 3 and 10, the steering angle error detection means 16Eb determines whether or not the own vehicle 1 has run through the first set distance Lb for detecting the steering angle error after traveling by the constant distance La. The travel detection processing (step # 6) is performed, and the steering angle error θe is detected at every set time until the host vehicle 1 breaks the first set distance Lb for steering angle error detection, and the host vehicle 1 The average value of a plurality of steering angle errors θe detected for each setting time is obtained as the vehicle travels through the first set distance Lb, and the average value is set as the steering angle error θe for steering angle calculation processing. The conversion process (step # 7) is performed.
Thereby, the detection accuracy of the steering angle error θe by the steering angle error detection means 16Eb can be enhanced. Then, the steering angle calculation means 16Ec outputs the target steering angle θs calculated based on the steering angle error θe with high accuracy to the power steering mechanism 12, thereby a running offset with respect to the target route P of the vehicle 1 at the time of autonomous running. The quantity So can be reduced more reliably. As a result, it is possible to more effectively suppress the decrease in work accuracy due to the traveling offset.

The second run determination processing that determines whether or not the own vehicle 1 has run through the second set distance Lc for re-detection of the steer angle error longer than the first set distance Lb (step # 9). Each time the vehicle 1 travels the second set distance Lc, the steering angle error θe is updated by re-detecting the average value of the steering angle error θe based on the processing procedure described above.
Thus, the steering angle error detection means 16Eb can increase the detection accuracy of the steering angle error θe every time the steering angle error θe is updated by the update processing, and the steering angle calculation means 16Ec can increase the accuracy every update. The target steering angle θs calculated based on the steering angle error θe can be output to the power steering mechanism 12. As a result, the travel offset amount So with respect to the target route P of the vehicle 1 at the time of autonomous travel can be reduced as the autonomous traveling distance of the vehicle 1 at the straight traveling work route portion P1 becomes longer. The drop can be more effectively suppressed.
The difference between the first set distance Lb for detecting the steering angle error and the second set distance Lc for detecting the steering angle error is the target steering based on the steering angle error θe obtained in the traveling of the first set distance Lb. In the autonomous traveling by the automatic steering after the angle θs is corrected, the traveling distance until the autonomous traveling settles is set in consideration.

As shown in FIG. 10, the steering angle error detection means 16Eb determines whether or not the vehicle 1 has shifted from the straight work path P1 to the direction change path P2 during execution of the averaging process described above. The shift determination process (step # 8) is performed, and when the shift is made, the averaging process at this time is ended, and the averaging stop process (step # 10) in which the average value of the steering angle error θe is not obtained.
As a result, in the averaging process of the steering angle error θe, the steering is performed by the steering angle error θe at the time of direction change having a component different from the steering angle error θe at the time of straight running mixed with the steering angle error θe at the straight running It is possible to prevent the decrease in detection accuracy of the angular error θe.

Although not shown, the steering angle error detection means 16Eb determines whether the present straight working path portion P1 is an odd-numbered row or an even-numbered row each time the own vehicle 1 starts autonomous traveling on each straight working path portion P1. The number sequence determination processing is performed, and if the current straight operation path portion P1 is an odd row (outbound portion), the steering angle error for forward movement is detected as the steering angle error θe detected during autonomous traveling on the current straight operation path portion P1. In the updating process described above, the forward steering angle error θe is updated each time the forward steering angle error θe is detected. Further, if the straight traveling work path portion P1 at this time is an even-numbered row (returning path portion), the steering angle error θe detected during autonomous traveling at the straight traveling work path portion P1 this time is the steering angle error θe for returning home. In the updating process, the return steering angle error θe is updated each time the return steering angle error θe is detected.
The steering angle calculation means 16Ec performs the azimuth angle deviation calculation process described above on the forward steering angle error θe if the current straight working path portion P1 is an odd number row based on the determination result obtained by the above-described number sequence determination process. The steering angle calculation processing for the forward road to be added to the azimuth deviation θd obtained in the above is performed. Further, if the straight working path portion P1 this time is an even number row, the steering angle calculation processing for the return path is performed to add the steering angle error θe for the return path to the azimuth angle deviation θd obtained by the azimuth deviation calculation processing described above. .
As a result, when the positioning unit 19 measures an error in the yaw angle of the vehicle 1 measured by the positioning unit 19, the vehicle 1 travels autonomously in the straight work path portion (outgoing route portion) P1 of the odd number row and even number When there is a difference in the steering angle error θe when autonomous traveling on the straight traveling work path portion (return path portion) P1 of the row, the steering angle error θe for the forward path is updated by the steering angle error θe for the return path Alternatively, it is possible to prevent a decrease in the detection accuracy of the steering angle error θe caused by the return path steering angle error θe being updated by the forward path steering angle error θe.
Specifically, for example, in a field where the heading of the straight working path part (outbound part) P1 of the odd number row is true north and the heading of the straight working path part (return part) P1 of the even number is true south When the car 1 travels autonomously in the straight work path portion (forward path portion) P1 in an odd number row, the azimuth of the vehicle 1 measured by the positioning unit 19 is 0 degrees, and the vehicle 1 is an even number row It is ideal that the azimuth of the vehicle 1 measured by the positioning unit 19 is 180 degrees when autonomous traveling on the straight working path portion (return path portion) P1 of Even though the own vehicle 1 autonomously travels in the straight-ahead work path part (outbound part) P1 of the odd number row due to an error in the yaw angle of the own vehicle 1 measured by 19 and the like, The orientation of the vehicle 1 measured by the unit 19 may be slightly deviated from 0 degrees, and the vehicle 1 may Straight working path portion of the sequence (the return portions) P1 Despite the autonomous, the orientation of the vehicle 1, the positioning unit 19 measures there is a little deviated from 180 degrees.
Thus, originally, the direction of the vehicle 1 when the vehicle 1 autonomously travels in the straight movement work route portion (forward route portion) P1 of the odd number row, and the straight movement work route portion of the even vehicle 1 (return route Part) Although the angle difference with the direction of the host vehicle 1 when traveling autonomously on P1 should be 180 degrees, there may be a disadvantage that it does not become 180 degrees due to a positioning error.
However, when the vehicle 1 travels autonomously in the same straight line work path portion P1 of the same odd number row or the same even number row, the direction of the deviation of the direction due to the positioning error tends to be constant. The steering angle error θe for the odd row (outbound path) and the steering angle error θe for the even row (return path) are separately detected and individually updated.
As a result, it is possible to obtain the forward path steering angle error θe and the return path steering angle error θe with high detection accuracy.
Then, if the straight work path portion P1 on which the vehicle 1 travels autonomously is the outward path portion, the target steering angle θs at this time can be calculated to a suitable value in which the steering angle error θe for the outward path is taken into consideration. By outputting the target steering angle θs to the power steering mechanism 12, the traveling offset amount So to the straight working path P1 of the vehicle 1 at the time of autonomous traveling in the straight working path P1 for the outgoing route is reduced more suitably. be able to. Further, if the straight work path portion P1 on which the vehicle 1 travels autonomously is the return path portion, the target steering angle θs at this time can be calculated to a suitable value in which the steering angle error θe for the return path is taken into consideration. By outputting the target steering angle θs to the power steering mechanism 12, the traveling offset amount So to the straight working path P1 of the own vehicle 1 is suitably reduced at the time of autonomous traveling on the straight working path P1 for returning. be able to.

The steering angle error detection means 16Eb performs storage processing for storing the latest steering angle error θe in the on-vehicle storage unit 16D every time the steering angle error θe is detected or updated, and the steering angle calculation means 16Ec performs the above-described detection prohibition process. Calculates the target steering angle θs by adding the steering angle error θe stored in the on-vehicle storage unit 16D to the azimuth angle deviation θd obtained by the azimuth angle deviation calculation processing while detection of the steering angle error θe is prohibited by Do.
Thus, even during autonomous travel in which detection of the steering angle error θe is prohibited by the detection prohibiting process, the target steering angle θs can be calculated to a suitable value in which the steering angle error θe is considered, and this target steering angle By outputting θs to the power steering mechanism 12, the travel offset amount So with respect to the target route P of the vehicle 1 can be reduced.
Further, as described above, since the on-vehicle storage unit 16D is nonvolatile, even if the key-on operation is performed and the autonomous traveling is started after the power is turned off by the key-off operation of the vehicle 1, By adding the steering angle error θe stored in the on-vehicle storage unit 16D to the azimuth angle deviation θd obtained by the azimuth angle deviation calculation processing, it is possible to calculate the target steering angle θs in which the steering angle error θe is taken into consideration. The traveling offset amount So with respect to the target route P of the vehicle 1 can be reduced.

[Another embodiment]
Another embodiment of the first embodiment of the present invention will be described.
In addition, the configuration of each embodiment described below is not limited to being individually applied, and may be applied in combination with the configuration of the other embodiments.

(1) The configuration of the work vehicle can be variously changed.
For example, the work vehicle may be configured in a hybrid specification including the engine 10 and an electric motor for traveling, or may be configured in an electric specification including an electric motor for traveling in place of the engine 10 .
For example, the work vehicle may be configured in a semi crawler specification provided with left and right crawlers instead of the left and right rear wheels 8.
For example, the work vehicle may be configured in a rear wheel steering specification in which the left and right rear wheels 8 function as steered wheels.

(2) If the steering angle sensor 18 is configured such that the automatic steering unit 32 interlocks the steering wheel 20 and the left and right front wheels (steering wheels) 7 by mechanical linkage, the rotational operation direction and rotational operation amount of the steering wheel 20 The steering angle of the front wheel (steering wheel) 7 may be detected on the basis of this.

(3) The azimuth deviation calculation means 16Ea sets the predetermined distances D1a to D1c for target point setting in the target point setting processing set to different lengths according to the type of each of the route parts P1 to P5 manually by the user. It may be configured to change based on the operation.

(4) The azimuth deviation calculation means 16Ea determines the degree of roughness of the field based on the attitude angle (roll angle and pitch angle) of the vehicle 1 measured by the positioning unit 19, and determines the degree of roughness of the determined field. In the target point setting process, the predetermined distance D1 for target point setting may be automatically changed.

(5) The azimuth deviation calculation means 16Ea determines that the target point p2 set on the target route by the target point setting process in the autonomous traveling of the vehicle 1 is the route portion P1 to P5 in which the vehicle 1 is currently traveling. When the end point is reached, the target point p2 may be configured to be changed from the path portion currently being traveled by the vehicle 1 to the next path portion.

(6) The azimuth deviation calculation means 16Ea automatically changes the predetermined distances D1a to D1c for target point setting in the target point setting process according to the type of each of the route parts P1 to P5 on which the vehicle 1 travels autonomously. In such a case, as the current position p1 of the vehicle 1 shifts from the current route part P1 to P5 to the next route part P1 to P5, it corresponds to the current route part P1 to P5. The predetermined distances D1a to D1c for target point setting may be changed to the predetermined distances D1a to D1c for target point setting corresponding to the next route parts P1 to P5.

(7) The steering angle error detection means may be configured to detect the steering angle error by teaching traveling on the target route of the vehicle 1 before work traveling.

Second Embodiment
A second embodiment in which an autonomous traveling system for a work vehicle according to the present invention is applied to a tractor which is an example of a work vehicle will be described based on the drawings.
The autonomous traveling system for work vehicles according to the present invention is a work vehicle other than a tractor, such as a riding rice planter, a combine, a riding grass mower, a wheel loader, a snow removal vehicle, and an unmanned grass mower etc. It can be applied to vehicles.

As shown in FIGS. 12 to 13, the autonomous traveling system for a work vehicle illustrated in the second embodiment is set to be communicable with the autonomous traveling unit 2 mounted on the tractor 1 and the autonomous traveling unit 2. Mobile communication terminal 3 and the like. As the mobile communication terminal 3, a tablet-type personal computer, a smart phone, or the like having a touch-operable liquid crystal panel 4 or the like can be adopted.

As shown in FIG. 12, the tractor 1 is connected to the rotary tillage specification by the rotary tilling device 6 which is an example of the working device being connected to the rear portion via the three-point link mechanism 5 so as to be movable up and down. It is configured.
In addition, it can replace with the rotary tilling apparatus 6, and can connect work apparatuses, such as a plow, a sowing apparatus, a scattering apparatus, to the rear part of the tractor 1. FIG.

As shown in FIGS. 12 to 13, the tractor 1 includes left and right front wheels 7 functioning as drivable steerable wheels, left and right drivable rear wheels 8, a cabin 9 forming a riding type driving unit, and a common rail system. An electronically controlled diesel engine (hereinafter referred to as the engine) 10, an electronically controlled transmission 11 for shifting power from the engine 10, a full hydraulic power steering mechanism 12 for steering the left and right front wheels 7, The left and right side brakes (not shown) that brake the rear wheel 8, the electronically controlled brake operation mechanism 13 that enables hydraulic operation of the left and right side brakes, and the working clutch that interrupts transmission to the rotary cultivator 6 (Not shown), an electronically controlled clutch operating mechanism 14 which enables hydraulic operation of the working clutch, and an electronic hydraulic control type rising and lowering drive of the rotary cultivator 6 A drive mechanism 15, an on-vehicle electronic control unit (hereinafter referred to as an on-vehicle ECU) 16 having various control programs related to autonomous traveling of the vehicle (tractor) 1, etc., a vehicle speed sensor 17 for detecting the vehicle speed of the vehicle 1, A steering angle sensor 18 for detecting the steering angle of the vehicle, and a positioning unit 19 for measuring the current position and the current direction of the vehicle 1 are provided.
The engine 10 may be an electronically controlled gasoline engine equipped with an electronic governor. For the transmission 11, a hydromechanical continuously variable transmission (HMT), a hydrostatic continuously variable transmission (HST), a belt type continuously variable transmission, or the like can be adopted. The power steering mechanism 12 may be, for example, an electric power steering mechanism 12 provided with an electric motor.

As shown in FIG. 12, a steering wheel 20 and a seat 21 for a user are provided inside the cabin 9 to enable manual steering of the left and right front wheels 7 via the power steering mechanism 12. Also, although not shown, a shift lever that enables manual operation of the transmission 11, a left and right brake pedal that enables manual operation of the left and right side brakes, and a manual lifting operation of the rotary tilling device 6 Lift levers, etc. are provided.

As shown in FIG. 13, the on-vehicle ECU 16 controls a shift control unit 16A that controls the operation of the transmission 11, a braking control unit 16B that controls the operation of the left and right side brakes, and a work device control that controls the operation of the rotary tilling device 6. 16C, a non-volatile vehicle storage unit 16D for storing a previously generated target route P for autonomous traveling, etc., and the target steering angle θs of the front wheels 7 on both sides during autonomous traveling, and output to the power steering mechanism 12 Steering angle setting unit 16E, and the like.

As shown in FIGS. 12-14, the positioning unit 19 uses the GPS (Global Positioning System), which is an example of the Global Navigation Satellite System (GNSS), to determine the current position p1 of the vehicle 1 and An inertial measurement unit (IMU: Inertial Measurement Unit) that measures the attitude, orientation, etc. of the vehicle 1 with a satellite navigation device 22 that measures the current orientation θ1, a three-axis gyroscope, three-direction acceleration sensors, etc. ) 23, etc. are provided. Positioning methods using GPS include DGPS (Differential GPS: relative positioning method), RTK-GPS (Real Time Kinematic GPS: interference positioning method), etc. In the second embodiment, it is suitable for positioning of a mobile object. RTK-GPS is adopted. Therefore, a reference station 24 that enables positioning by RTK-GPS is installed at a known position around the farmland.

GPS antennas

26 and 27 for receiving radio waves transmitted from the GPS satellite 25.

Communication modules

As shown in FIGS. 13 to 14, the mobile communication terminal 3 includes a terminal electronic control unit (hereinafter referred to as a terminal ECU) 30 having various control programs for controlling the operation of the liquid crystal panel 4 and the like, and a tractor side. And a communication module 31 that enables wireless communication of various data including positioning data with the communication module 28 of FIG. The terminal ECU 30 is a non-volatile terminal storing a target route generation unit 30A that generates a target route P for autonomous traveling, and various input data input by the user, the target route P generated by the target route generation unit 30A, and the like. A storage unit 30B and the like are included.

As shown in FIGS. 12 to 14, the target route generation unit 30A follows the input guidance for target route generation displayed on the liquid crystal panel 4, vehicle data such as the type and model of the work vehicle and the work device, and When the target field position and the like are input by the user, it is determined whether or not the corresponding target route P is stored in the terminal storage unit 30B based on the input vehicle data, the field position, and the like. When the corresponding target route P is stored, the target route P is read from the terminal storage unit 30 B and displayed on the liquid crystal panel 4. When the corresponding target route P is not stored, the liquid crystal panel 4 displays an execution guidance of positioning data acquisition travel for obtaining positioning data necessary for generation of the target route P, and the user performs positioning data acquisition travel. Let Then, based on the positioning data and the like obtained by wireless communication with the tractor 1 during this positioning data acquisition traveling, the field data such as the section and the shape of the work field and the like are acquired, and the acquired field data and vehicle data The target route P suitable for working on the field to be worked with this tractor 1 is generated on the basis of the minimum turning radius, the working width, etc. included in. Then, the generated target route P is displayed on the liquid crystal panel 4 and stored in the terminal storage unit 30B as route data associated with the vehicle data and the field data. The route data includes an azimuth angle θp of the target route P, a target engine rotation speed, a target vehicle speed, and the like set according to the traveling mode of the tractor 1 on the target route P and the like.

As shown in FIG. 14, in the second embodiment, a field divided into a rectangular shape is illustrated as a field to be worked. In addition, as a target route P suitable for the rectangular field, a plurality of straight movement work path portions P1 having the same straight movement distance and arranged in parallel with a predetermined distance corresponding to the work width, and adjacent straight movement A reciprocating traveling route is illustrated, which includes a plurality of direction change path portions P2 extending from the end point P1e of the working path portion P1 to the start point P1s and causes the tractor 1 to reciprocate from the start point Ps of the target path P to the end point Pe. ing. Of the plurality of rectilinear work path portions P1, the odd-numbered row is the forward path portion, and the even-numbered row is the return path portion. The plurality of direction change path portions P2 are a first turning path portion P3 for turning the tractor 1 by 90 degrees from the end point P1e of the straight working path portion P1 toward the next straight working path portion, and a first turning path portion P3. A straight forward path P4 for moving the tractor 1 straight backward from the turning end point P3e toward the previous straight working path, and a starting point of the next straight working path P1 from a backward finish point P4e of the backward straight path P4 It is divided by the 2nd turning course part P5 which turns the tractor 1 90 degrees toward the point P1s.
That is, the target route P is divided into a plurality of types of route portions P1 to P5 in accordance with the traveling mode of the vehicle 1.
The target path P shown in FIG. 14 is merely an example, and the target path P is, for example, a plurality of direction change path portions P2, and from the end point P1e of the straight work path portion P1 to the start end of the next straight work path portion P1. It may be generated so as to include a U-turn path portion that turns the tractor 1 180 degrees toward the point P1s.

As shown in FIGS. 13 to 14, in the state where the target route P is confirmed and displayed on the liquid crystal panel 4, the terminal ECU 30 instructs execution of autonomous traveling by the operation of the liquid crystal panel 4 by the user. The target route P being displayed together with the execution command is transmitted to the in-vehicle ECU 16 via the

communication modules

To describe the setting of the target steering angle θs in detail, as shown in FIGS. 13 to 18, the steering angle setting unit 16E has steering angle calculation means 16Ed that calculates the target steering angle θs at the time of autonomous traveling. The steering angle calculation means 16Ed sets target point p2 on a target route with a predetermined distance D1 from the current position p1 of the vehicle 1 to the traveling direction side during autonomous traveling, and the current position of the vehicle 1 A line segment generation process for generating a line segment L1 from the position p1 to the target point p2 and a target steering angle calculation process for calculating an angle formed by the current direction θ1 of the vehicle 1 and the line segment L1 as a target steering angle θs .

Describing the target steering angle calculation processing in detail, as shown in FIGS. 15 to 16, in the target steering angle calculation processing, if the current travel route of the host vehicle 1 is the straight work route portion P1 or the rear straight advance route portion P4. If the direction from the current position p1 of the vehicle 1 to the target point p2 (the azimuth of the line segment L1) is the target azimuth angle θ2, and the angle between the target path P and the line segment L1 is the traveling correction angle θc The target azimuth angle θ2 at the work path portion P1 is
Target azimuth angle θ2 = azimuth angle θp1 of straight working path portion P1 + traveling correction angle θc
The target azimuth angle θ2 at the rear straight path portion P4 is
Target azimuth angle θ2 = azimuth angle θp4 of the rear straight path portion P4 + traveling correction angle θc
It becomes.
Here, the azimuth angle θp1 of the straight working path portion P1 and the azimuth angle θp4 of the backward straight path portion P4 are known at the stage of generating the target path P, but when these are calculated, the straight working path portion P1 is Assuming that the E component (x component) of the vector V1 from the start point P1s to the end point P1e is V1e and the N component (y component) of the vector V1 is V1n,
Azimuth angle θp1 = atan2 (V1e, V1n) of the straight working path portion P1
It becomes. Further, assuming that the E component (x component) of the vector V4 from the start position to the end position of the straight rear path portion P4 is V4e and the N component (y component) of the vector V4 is V4n,
Azimuth angle θp4 = atan2 (V4e, V4n) of the rear straight path portion P4
It becomes. Then, assuming that the travel correction angle θc is a lateral deviation from the travel route of the vehicle 1 on the NED coordinates as D2, the predetermined distance for setting the target point is D1,
Travel correction angle θc = asin (lateral deviation D2 / predetermined distance D1)
Thus, the target azimuth angle θ2 can be determined, and the target steering angle θs can be obtained from the difference between the determined target azimuth angle θ2 and the attitude angle (yaw angle) θ1 of the vehicle 1 measured by the positioning unit 19 Can.
On the other hand, as shown in FIGS. 17 to 18, if the current travel route of the vehicle 1 is the first turning path portion P3 or the second turning path portion P5, the turning centers pt of those turning path portions P3 and P5. Assuming that the angle between the vector Vv and the N axis from the vehicle to the vehicle 1 is θv, the target steering angle θs is obtained from the above-mentioned angle θv, the current direction θ1 of the vehicle 1 and the travel correction angle θc
Target steering angle θs = angle θv + SignTrn × 90−present direction θ1 + SignTrn × (90−travel correction angle θc)
It can be determined by
Here, degrees are used for all units in this formula, and "90" in the formula indicates 90 degrees. Further, with regard to “Sign Trn”, it is “1” when the turning direction is the clockwise direction, and “−1” when the turning direction is the counterclockwise direction. The travel correction angle θc in the above equation is a predetermined distance D1 for setting a target point, a distance D3 from the turning center pt of the turning path portions P3 and P5 to the vehicle 1, and turning of the turning path portions P3 and P5. From the radius R,
Travel correction angle θc = acos ((D3 ^ 2 + D1 ^ 2-R ^ 2) / (2 × D3 × D1)
The distance D3 from the turning center pt of the turning path portions P3 and P5 to the vehicle 1 in this equation is the turning radius R of the turning path portions P3 and P5, and the distance D3 of the vehicle 1 on the NED coordinates. From the lateral deviation D2 from the turning path parts P3 and P5,
Distance D3 = turning radius R + lateral deviation D2
It can be determined by
That is, the calculation load applied to the steering angle calculation means 16Ed can be reduced in the target steering angle calculation processing described above.

As shown in FIGS. 15-18, in the on-vehicle storage unit 16D, a plurality of predetermined distances D1a-D1c for setting target points set to different lengths according to the type of each of the route parts P1-P5 in the target route P. Is stored. The steering angle calculation means 16Ed automatically changes the predetermined distance D1 for target point setting in the target point setting process according to the type of each of the route portions P1 to P5 on which the vehicle 1 travels autonomously on the target route P.
As a result, it is possible to eliminate the trouble of the user manually changing the predetermined distance D1 in accordance with the types of the route portions P1 to P5 on which the tractor 1 travels autonomously. In addition, it is possible to prevent the calculation accuracy of the target steering angle θs from being lowered due to the user mistaking the predetermined distance D1 or forgetting to change the predetermined distance D1.

With respect to the predetermined distance D1 for setting the target point, the steering angle calculation means 16Ed is, as shown in FIG. 15, the predetermined distance D1 when the current position p1 of the vehicle 1 is the straight work path part P1. It is changed to the first predetermined distance D1a suitable for autonomous traveling on the straight working path portion P1.
When the current position p1 of the vehicle 1 is the backward straight path portion P4 as shown in FIG. 16, the steering angle calculation means 16Ed travels autonomously in the backward straight path portion P4 by the predetermined distance D1. To a second predetermined distance D1b suitable for The second predetermined distance D1b is a rear steering that steers the left and right front wheels 7 on the rear side in the traveling direction and corrects the traveling direction when the vehicle 1 corrects the traveling direction in autonomous traveling on the rear straight traveling path portion P4. The distance is set to be longer than the first predetermined distance D1a in consideration of an increase in the amount of shake.
If the current position p1 of the vehicle 1 is the first turning path portion P3 or the second turning path portion P5 as shown in FIGS. It changes into the 3rd predetermined distance D1c suitable for carrying out autonomous travel in the 1st turning course part P3 or the 2nd turning course part P5. The third predetermined distance D1c is a first predetermined distance in consideration of the fact that the vehicle 1 is easily separated from the turning path portions P3 and P5 during autonomous traveling on the first turning path portion P3 or the second turning path portion P5. The distance is set to be shorter than the predetermined distance D1a and the second predetermined distance D1b.

As shown in FIG. 19, the steering angle calculation means 16Ed is the next path part (for example, the first turning path part P3) of which the current position p1 of the vehicle 1 is different from the current path part (for example, straight working path part P1). Until switching to), the target point p2 is set on the extension of the current route portion.
Thus, for example, while the vehicle 1 travels autonomously in the straight operation path portion P1, it is possible to set a target point p2 suitable for autonomous traveling in the straight operation path portion P1, and from the target point p2 It is possible to calculate the target steering angle θs suitable for autonomous traveling on the straight working path portion P1. In addition, while the vehicle 1 travels autonomously in the first turning path portion P3, a target point p2 suitable for autonomous traveling in the first turning path portion P3 can be set, and from the target point p2 It is possible to calculate the target steering angle θs suitable for autonomous traveling on the single turning path portion P3. As a result, it is possible to improve the traveling accuracy when the vehicle 1 travels autonomously on the target route P.

By the way, as shown in FIG. 20, in the working vehicle such as the tractor 1, the steering angle error θe caused by the individual difference of the steering angle sensor 18 is included in the steering system. Due to the angular error θe, the work vehicle travels with a constant travel offset amount So for the target route P remaining. As a result, the working accuracy is reduced due to the traveling offset.

Therefore, as shown in FIG. 13, in addition to the steering angle calculation means 16Ed, the steering angle setting unit 16E detects a steering angle error detection means 16Ee that detects a steering angle error θe during autonomous traveling, and a steering angle error θe. And steering angle correction means 16Ef for correcting the target steering angle θs.

As shown in FIGS. 21-22, the steering angle error detection means 16Ee moves from the current position p1 of the vehicle 1 to the traveling direction during straight traveling by autonomous traveling of the vehicle 1 on the straight operation route portion P1 of the target route P. A fixation point setting process (step # 3) for setting a fixation point p3 on a target route with a fixed distance D4 (front side) and a line for generating a line L2 from the current position of the vehicle 1 to the fixation point p3 A minute generation process (step # 4) and a steering angle error calculation process (step # 5) for calculating an angle formed by the target path P and the line segment L2 as the steering angle error θe are performed. Then, in the steering angle error calculation process, assuming that the lateral deviation from the straight working path portion P1 of the vehicle 1 on the NED coordinates is D5, the constant distance for setting the fixation point is D4, The angular error θe
Steering angle error θe = asin (lateral deviation D5 / fixed distance D4)
It can be determined by
The steering angle correction means 16Ef performs correction processing to add the steering angle error θe obtained by the steering angle error calculation processing to the target steering angle θs obtained by the target steering angle calculation processing described above.
As a result, the target steering angle θs can be corrected to a value in which the steering angle error θe is taken into consideration. By outputting the target steering angle θs after this correction processing to the power steering mechanism 12, the own vehicle at the time of autonomous traveling The travel offset amount So for one target route P can be reduced. As a result, it is possible to suppress a decrease in work accuracy due to the traveling offset.

As shown in FIGS. 14 and 21 to 22, the steering angle error detection unit 16Ee determines whether or not a predetermined condition for allowing detection of the steering angle error θe is satisfied (step # 1). And, the detection prohibiting process (step # 2) of prohibiting the detection of the steering angle error θe is performed until the predetermined condition is satisfied.
In the second embodiment, as a predetermined condition, it is set whether or not a predetermined distance La necessary for the autonomous traveling to settle after the autonomous vehicle 1 has started the autonomous traveling on the straight operation path portion P1 is run. ing. Then, in the detection condition determination process, the steering angle error detection means 16Ee assumes that the predetermined condition is satisfied when the own vehicle 1 starts traveling autonomously on the straight work path portion P1 and then runs through the fixed distance La. It is configured to make a determination, whereby the detection prohibiting process is performed by the detection prohibiting process from when the vehicle 1 starts autonomous traveling on the straight working path portion P1 until it runs through the predetermined distance La. Detection is prohibited.
As a result, detection of the steering angle error θe and target steering based on the detected steering angle error θe also from when the vehicle 1 starts autonomous traveling on the straight working path portion P1 until the autonomous traveling is settled. The correction of the angle θs reduces the detection accuracy of the steering angle error θe, and the target steering angle θs is corrected based on the steering angle error θe having a low detection accuracy and is output to the power steering mechanism 12 As a result, it is possible to avoid the occurrence of the inconvenience that the traveling offset amount So with respect to the target route P of the vehicle 1 at the time of autonomous traveling hardly decreases.

As shown in FIG. 14 and FIG. 22, the steering angle error detection means 16Ee determines whether or not the own vehicle 1 has run through the first set distance Lb for detecting the steering angle error after running the constant distance La. The travel detection processing (step # 6) is performed, and the steering angle error θe is detected at every set time until the host vehicle 1 breaks the first set distance Lb for steering angle error detection, and the host vehicle 1 As traveling through the first set distance Lb, averaging processing is performed to obtain an average value of a plurality of steering angle errors θe detected for each setting time, and set the average value as the steering angle error θe for correction processing Perform (Step # 7).
Thus, the detection accuracy of the steering angle error θe by the steering angle error detection means 16Ee can be enhanced. Then, the steering angle correction means 16Ef outputs the target steering angle θs corrected with the steering angle error θe with high accuracy to the power steering mechanism 12 to make the travel offset amount So to the target route P of the vehicle 1 at the time of autonomous traveling. Can be lowered more reliably. As a result, it is possible to more effectively suppress the decrease in work accuracy due to the traveling offset.

The second run determination processing (step # 9) determines whether the steering angle error detection means 16Ee has run through the second set distance Lc for re-detection of the steer angle error longer than the first set distance Lb. Each time the vehicle 1 travels the second set distance Lc, the steering angle error θe is updated by re-detecting the average value of the steering angle error θe based on the processing procedure described above.
As a result, the steering angle error detection means 16Ee can increase the detection accuracy of the steering angle error θe every time the steering angle error θe is updated by the updating process, and the steering angle correction means 16Ef can increase the accuracy every update. The target steering angle θs corrected based on the steering angle error θe can be output to the power steering mechanism 12. As a result, the travel offset amount So with respect to the target route P of the vehicle 1 at the time of autonomous travel can be reduced as the autonomous traveling distance of the vehicle 1 at the straight traveling work route portion P1 becomes longer. The drop can be more effectively suppressed.
The difference between the first set distance Lb for detecting the steering angle error and the second set distance Lc for detecting the steering angle error is the target steering based on the steering angle error θe obtained in the traveling of the first set distance Lb. In the autonomous traveling by the automatic steering after the angle θs is corrected, the traveling distance until the autonomous traveling settles is set in consideration.

As shown in FIG. 22, the steering angle error detection means 16Ee determines whether or not the vehicle 1 has shifted from the straight work path P1 to the direction change path P2 during execution of the averaging process described above. The shift determination process (step # 8) is performed, and when the shift is made, the averaging process at this time is ended, and the averaging stop process (step # 10) in which the average value of the steering angle error θe is not obtained.
As a result, in the averaging process of the steering angle error θe, the steering is performed by the steering angle error θe at the time of direction change having a component different from the steering angle error θe at the time of straight running mixed with the steering angle error θe at the straight running It is possible to prevent the decrease in detection accuracy of the angular error θe.

Although not shown, the steering angle error detection means 16Ee determines whether the present straight working path portion P1 is an odd number row or an even number row each time the own vehicle 1 starts the autonomous traveling on each straight portion working path portion P1. The number sequence determination processing is performed, and if the current straight operation path portion P1 is an odd row (outbound portion), the steering angle error for forward movement is detected as the steering angle error θe detected during autonomous traveling on the current straight operation path portion P1. In the updating process described above, the forward steering angle error θe is updated each time the forward steering angle error θe is detected. Further, if the straight traveling work path portion P1 at this time is an even-numbered row (returning path portion), the steering angle error θe detected during autonomous traveling at the straight traveling work path portion P1 this time is the steering angle error θe for returning home. In the updating process, the return steering angle error θe is updated each time the return steering angle error θe is detected.
The steering angle correction means 16Ef executes the target steering angle calculation processing described above for the forward steering angle error θe if the current straight working path portion P1 is an odd number row based on the determination result obtained by the above-described number sequence determination processing. A correction process for the forward path to be added to the target steering angle θs obtained in the above is performed. Further, if the current straight working path portion P1 is an even-numbered row, correction processing for the return path is performed to add the steering angle error θe for the return path to the target steering angle θs obtained by the target steering angle calculation processing described above.
As a result, when the positioning unit 19 measures an error in the yaw angle of the vehicle 1 measured by the positioning unit 19, the vehicle 1 travels autonomously in the straight work path portion (outgoing route portion) P1 of the odd number row and even number When there is a difference in the steering angle error θe when autonomous traveling on the straight traveling work path portion (return path portion) P1 of the row, the steering angle error θe for the forward path is updated by the steering angle error θe for the return path Alternatively, it is possible to prevent a decrease in the detection accuracy of the steering angle error θe caused by the return path steering angle error θe being updated by the forward path steering angle error θe.
Specifically, for example, in a field where the heading of the straight working path part (outbound part) P1 of the odd number row is true north and the heading of the straight working path part (return part) P1 of the even number is true south When the car 1 travels autonomously in the straight work path portion (forward path portion) P1 in an odd number row, the azimuth of the vehicle 1 measured by the positioning unit 19 is 0 degrees, and the vehicle 1 is an even number row It is ideal that the azimuth of the vehicle 1 measured by the positioning unit 19 is 180 degrees when autonomous traveling on the straight working path portion (return path portion) P1 of Even though the own vehicle 1 autonomously travels in the straight-ahead work path part (outbound part) P1 of the odd number row due to an error in the yaw angle of the own vehicle 1 measured by 19 and the like, The orientation of the vehicle 1 measured by the unit 19 may be slightly deviated from 0 degrees, and the vehicle 1 may Straight working path portion of the sequence (the return portions) P1 Despite the autonomous, the orientation of the vehicle 1, the positioning unit 19 measures there is a little deviated from 180 degrees.
Thus, originally, the direction of the vehicle 1 when the vehicle 1 autonomously travels in the straight movement work route portion (forward route portion) P1 of the odd number row, and the straight movement work route portion of the even vehicle 1 (return route Part) Although the angle difference with the direction of the host vehicle 1 when traveling autonomously on P1 should be 180 degrees, there may be a disadvantage that it does not become 180 degrees due to a positioning error.
However, when the vehicle 1 travels autonomously in the same straight line work path portion P1 of the same odd number row or the same even number row, the direction of the deviation of the direction due to the positioning error tends to be constant. The steering angle error θe for the odd row (outbound path) and the steering angle error θe for the even row (return path) are separately detected and individually updated.
As a result, it is possible to obtain the forward path steering angle error θe and the return path steering angle error θe with high detection accuracy.
Then, if the straight work path P1 on which the vehicle 1 travels autonomously is the outward path portion, the target steering angle θs at this time can be corrected to a value in which the steering angle error θe for the outward path is taken into account. By outputting the subsequent target steering angle θs to the power steering mechanism 12, the traveling offset amount So to the straight working path P1 of the vehicle 1 at the time of autonomous traveling on the straight working path P1 for the outgoing route is reduced more suitably. It can be done. Further, if the straight work path portion P1 on which the vehicle 1 travels autonomously is the return path portion, the target steering angle θs at this time can be corrected to a value in which the steering angle error θe for the return path is taken into account. By outputting the subsequent target steering angle θs to the power steering mechanism 12, the traveling offset amount So to the straight working path P1 of the vehicle 1 at the time of autonomous traveling on the straight working path P1 for returning is reduced more suitably. It can be done.

The steering angle error detection means 16Ee performs storage processing for storing the latest steering angle error θe in the on-vehicle storage unit 16D every time the steering angle error θe is detected or updated, and the steering angle correction means 16Ef performs the above-described detection prohibition process Thus, while the detection of the steering angle error θe is prohibited, the target steering angle θs obtained in the target steering angle calculation process is corrected with the steering angle error θe stored in the on-vehicle storage unit 16D.
Thus, even during autonomous travel in which detection of the steering angle error θe is prohibited by the detection prohibiting process, the target steering angle θs obtained by the target steering angle calculation process is corrected to a value in which the steering angle error θe is taken into consideration. By outputting the target steering angle θs after this correction processing to the power steering mechanism 12, it is possible to reduce the travel offset amount So with respect to the target route P of the vehicle 1.
Further, as described above, since the on-vehicle storage unit 16D is nonvolatile, even if the key-on operation is performed and the autonomous traveling is started after the power is turned off by the key-off operation of the vehicle 1, The target steering angle θs obtained by the target steering angle calculation processing can be corrected by the steering angle error θe stored in the on-vehicle storage unit 16D, and the travel offset amount So to the target route P of the own vehicle 1 can be reduced. it can.

[Another embodiment]
Another embodiment of the second embodiment of the present invention will be described.
In addition, the configuration of each embodiment described below is not limited to being individually applied, and may be applied in combination with the configuration of the other embodiments.

(3) In the detection condition determination process, the steering angle error detection means 16Ee satisfies the predetermined condition when the vehicle 1 travels until the fixed time required from the start of the autonomous traveling to the settling of the autonomous traveling elapses. It may be determined that the steering angle error θe is detected.

(4) In the detection condition determination processing, the steering angle error detection means 16Ee determines that the predetermined condition is satisfied when the vehicle 1 travels the set distance set according to the vehicle speed from the start of autonomous traveling. The steering angle error θe may be detected.

(5) In the detection condition determination process, the steering angle error detection means 16Ee is for detecting the steering angle error the steering angle error θe obtained by the fixation point setting process, the line segment generation process, and the steering angle error calculation process described above. The steering angle error θe may be detected by determining that the predetermined condition is satisfied, when the steering angle error θe is decreased when the steering wheel angle drops below the set value.

(6) In the detection condition determination process, the steering angle error detection means 16Ee detects that the vehicle 1 is traveling autonomously in parallel with the target route P based on the measurement of the positioning unit 19 as a predetermined condition. It may be configured to detect the steering angle error θe by judging that

(7) In the averaging process, the steering angle error detection means 16Ee detects the steering angle error θe a plurality of times until the set time for detecting the steering angle error elapses, and performs the steering for the plurality of times. The average value of the angular error θe may be set as the steering angle error θe for the correction process.

(8) The steering angle error detection means 16Ee may be configured not to perform the averaging process described above.

(9) The steering angle error detection means 16Ee redetects the average value of the steering angle error θe or the steering angle error θe every time the setting time for steering angle error redetection elapses during autonomous traveling, and the steering angle error It may be configured to update θe.

(10) The steering angle error detecting means 16Ee redetects the average value of the steering angle error θe or the steering angle error θe every time the vehicle 1 travels the set distance set according to the vehicle speed, and the steering angle error It may be configured to update θe.

(11) The interval (travel distance, time, etc.) at which the steering angle error detection means 16Ee redetects the steering angle error θe or the average value of the steering angle error θe and updates the steering angle error θe You may constitute so that it can become possible to change a setting arbitrarily by operation. In this configuration, the update interval of the steering angle error θe can be optimized according to the field conditions and the like.

(12) While detecting the steering angle error θe, the steering angle error detection means 16Ee stops detecting the steering angle error θe when the deviation of the host vehicle 1 with respect to the target path P undergoes a drastic change over the set value. Then, when it is determined that the predetermined condition is satisfied in the detection condition determination process described above, the detection of the steering angle error θe may be resumed. In this configuration, it is possible to prevent the steering angle error θe based on the sudden change in deviation from being used for the correction of the target steering angle θs.

(13) The steering angle error detection means 16Ee individually detects each steering angle error θe according to the traveling mode such as forward, reverse or turning of the vehicle 1 at the time of autonomous traveling, and the on-vehicle storage unit 16D etc. May be configured to be stored. This configuration is suitable when the steering angle error θe changes in accordance with the traveling mode of the host vehicle 1.

(14) The steering angle error detection means 16Ee redetects the steering angle error θe and updates the steering angle error θe when updating of the steering angle error θe is instructed by the operation of the mobile communication terminal 3 or the like. It may be configured. In this configuration, for example, when the work vehicle 1 can not travel on the target route P accurately with accuracy, and changes in the wheel diameter and the wheel contact width due to the replacement of the

wheels

7 and 8 in the work vehicle 1, or In the case where the traveling characteristic changes due to the change of the rear wheel 8 to the crawler, the steering angle error θe can be arbitrarily updated by the operation of the mobile communication terminal 3 or the like.

(15) It is detected that a change in the vehicle state affecting the steering angle error θe such as replacement of the

wheels

7 and 8 or change of the left and right rear wheels 8 to crawlers has been performed on the work vehicle 1 A sensor may be provided, and when the sensor detects a change in the vehicle state, the steering angle error detection means 16Ee may be configured to automatically update the steering angle error θe.

The present invention relates to an autonomous travel system for work vehicles usable for unmanned work vehicles such as tractors, ride rice planters, combine harvesters, ride mowers, wheel loaders, snow removal vehicles, and unmanned work vehicles such as unmanned grass mowers. It can apply.

First Embodiment
1 self-vehicle 7 steering wheel 16D storage unit 16E steering angle setting unit 16Ea azimuth angle deviation computing means 16Eb steering angle error detecting means 16Ec steering angle computing means 18 steering angle sensor 19 positioning unit 32 automatic steering unit L1 target steering line D1 target direction line D1a Predetermined distance (first predetermined distance)
D1b predetermined distance (second predetermined distance)
D1c predetermined distance (third predetermined distance)
P Target path P1 Path part (straight work path part)
P2 route part (turning route part)
P3 path part (1st turning path part)
P4 path part (rear straight path part)
P5 path part (2nd turning path part)
p1 present position p2 target point θ1 present azimuth θd azimuth angle deviation θe steering angle error θs target steering angle [the second embodiment]
1 self-vehicle 7 steered wheels 16D storage unit 16E steering angle setting unit 16Ed steering angle calculation means 16Ee steering angle error detection means 16Ef steering angle correction means 18 steering angle sensor 19 positioning unit 32 automatic steering unit L2 line segment La for autonomous traveling setting Fixed distance Lb Set distance Lc for steering angle error detection Set distance P for steering angle error redetection Target path p1 Current position p3 Attention point θ1 Current direction θe Steering angle error θs Target steering angle

Claims

A storage unit for storing a target route generated in advance, a positioning unit for measuring a current position and a current direction of the vehicle, and an automatic steering unit for automatically steering steered wheels so that the vehicle autonomously travels the target route Equipped with
The automatic steering unit has a steering angle setting unit that sets a target steering angle of the steered wheels, and a steering angle sensor that detects a steered angle of the steered wheels.
The steering angle setting unit comprises azimuth angle deviation calculation means for calculating an azimuth angle deviation, steering angle error detection means for detecting a steering angle error during autonomous traveling, the target from the azimuth angle deviation and the steering angle error. And steering angle calculation means for calculating a steering angle,
The azimuth deviation calculation means is a target point setting process for setting a target point on the target route with a predetermined distance from the current position to the traveling direction side during autonomous traveling, and a target from the current position to the target point An autonomous traveling system for a work vehicle, comprising: line generation processing for generating an azimuth line; and azimuth deviation calculation processing for calculating an angle formed by the current azimuth and the target azimuth line as the azimuth deviation. .
The target route is divided into a plurality of types of route parts according to the traveling mode of the vehicle,
The storage unit stores a plurality of the predetermined distances set to different lengths according to the type of the path unit,
The autonomous traveling system for a work vehicle according to claim 1, wherein the azimuth deviation calculation means automatically changes the predetermined distance in accordance with a type of the route section on which the vehicle travels autonomously.
The target route is divided into a plurality of types of route parts according to the traveling mode of the vehicle,
The azimuth deviation calculation means sets the target point on an extension of the current route portion until the current position switches from the current route portion to a next route portion of a different type. The autonomous travel system for work vehicles according to 2.
A storage unit for storing a target route generated in advance, a positioning unit for measuring a current position and a current direction of the vehicle, and an automatic steering unit for automatically steering steered wheels so that the vehicle autonomously travels the target route Equipped with
The automatic steering unit has a steering angle setting unit that sets a target steering angle of the steered wheels, and a steering angle sensor that detects a steered angle of the steered wheels.
The steering angle setting unit corrects the target steering angle with a steering angle error, a steering angle calculation unit that calculates the target steering angle, a steering angle error detection unit that detects a steering angle error during autonomous traveling, and And a steering angle correction means,
The steering angle error detection means sets a gaze point setting process on the target route with a predetermined distance from the current position to the traveling direction side during autonomous traveling, and a line extending from the current position to the gaze point A line segment generation process for generating a minute, and a steering angle error calculation process for calculating an angle formed by the target route and the line segment as the steering angle error,
The autonomous travel system for a work vehicle, wherein the steering angle correction means performs correction processing for adding the steering angle error obtained by the steering angle error calculation processing to the target steering angle.
The steering angle error detection means determines whether or not a predetermined condition for allowing detection of the steering angle error is satisfied, and the steering angle error is detected until the predetermined condition is satisfied. The autonomous traveling system for a work vehicle according to claim 4, wherein a detection prohibition process of prohibiting detection is performed.
In the detection condition determination process, the steering angle error detection means determines that the predetermined condition is satisfied when the vehicle travels a certain distance required from the start of the autonomous traveling to the settling of the autonomous traveling. An autonomous travel system for a work vehicle according to Item 5.
The steering angle error detection means performs the detection of the steering angle error a plurality of times until the vehicle travels the set distance for detecting the steering angle error, and the average of the steering angle errors for a plurality of times is detected. The autonomous traveling system for a work vehicle according to any one of claims 4 to 6, wherein an averaging process is performed to obtain a value and use the average value as a steering angle error for correction process.
The steering angle error detection means redetects the steering angle error and updates the steering angle error each time the vehicle travels the set distance for steering angle error redetection during autonomous traveling. The autonomous travel system for work vehicles according to any one of 7.