Driving control device and driving control method

Abstract

To enable stable driving by suppressing lateral steering vibrations during practice runs based on the teacher's route. [Solution] The system includes a calculation angle calculation unit 14 that calculates a first calculation angle θd for correcting the direction of travel Φc at the current position of the work vehicle during practice driving based on multiple teacher points set on the teacher path to a direction toward the current target point, and a second calculation angle θt for correcting the current direction of travel Φc of the work vehicle to the direction of travel Φt at the teacher point designated as the current target point among the direction of travel of the work vehicle at multiple teacher points, and a control steering angle calculation unit 15 that calculates a control steering angle θf based on the two steering angles θd and θt. Even when the first calculation angle θd becomes quite large during turning in practice driving, the system mitigates the increase in the control steering angle θf by taking the second calculation angle θt into account when calculating the control steering angle θf, thereby suppressing the occurrence of steep large steering angle control.

Description

[Technical Field]

[0001] The present invention relates to a driving control device and a driving control method, and is particularly suitable for use in a device and method for controlling a work vehicle to learn by sequentially setting a plurality of training points acquired by the training run of the work vehicle as target points. [Background technology]

[0002] Conventionally, an automatic driving control system is known that is equipped on a work vehicle with a function to detect the vehicle's current position and direction, and automatically drives the work vehicle along a pre-set target route within the field based on the continuously detected current position and direction (see, for example, Patent Documents 1 to 3). The work vehicle performs a given task (agricultural work such as tilling, ridging, sowing, rice planting, and spraying chemicals) while automatically driving within the field.

[0003] In the automated driving work vehicle described in Patent Document 1, a first steering value for eliminating deviation is output based on the position deviation between the target driving path and the vehicle's position, and a second steering value for eliminating deviation is output based on the position deviation and the azimuth deviation adjusted using a weighting coefficient that tends to decrease as the position deviation increases. Based on the first steering value and the second steering value, a target steering value for driving along the target driving path is output.

[0004] In the driver assistance device described in Patent Document 2, a target point to which the moving body should move is set from the current position of the vehicle, the current turning center and target turning radius of the vehicle are calculated, and a control steering angle is calculated so that the turning radius converges to the target turning radius. The control steering angle is then output to the actuator steering device to control the steering. In other words, the control means controls the attitude control system of the moving body so that the turning radius of the moving body converges to the turning radius at the set target point.

[0005] The steering control device described in Patent Document 3 controls the steering of the vehicle based on the processing results of an image captured of the ground on which the vehicle is traveling, including the distant view in front of the vehicle. Specifically, a target area of ​​vehicle travel, composed of multiple pixel values ​​of the captured image, is sequentially detected while the vehicle is traveling, the turning angle of the vehicle is calculated based on the amount of change in the position of the target area, and the turning state of the vehicle is estimated based on the travel distance and the turning angle.

[0006] Incidentally, in automated driving, the target route is set as the training route, which is the route taken by an operator manually driving a work vehicle. In automated driving that replicates the training route, human-specific driving habits can induce instability in the driving control. In particular, human-specific habits tend to be more pronounced in large-angle steering turns. As a result, if the training control is simply performed to match human steering, there is a high possibility of steering vibration in the left and right directions due to abrupt, large-angle steering. Figure 9 is a diagram to explain the conventional problem, showing the training trajectory VP in a state where steering vibration occurred due to abrupt, large-angle steering control relative to the training route TR. To prevent the occurrence of such steering vibration, it is necessary to devise a way to stabilize the driving control while following the intent of the training route.

[0007] However, the technology described in Patent Document 1 above assumes that the target travel path is straight, and calculates the target steering value for traveling along the target travel path by using the length of the perpendicular line drawn from the vehicle body to the target travel path as the position deviation and the angle between the vehicle body's travel direction line and the target travel path as the azimuth deviation. As a result, there is a risk of overshoot or hunting occurring during turns.

[0008] The technology described in Patent Document 2 above calculates the control steering angle based on a control condition formula that is valid when the turning radius is sufficiently large in automobiles, and therefore cannot be applied to automatic driving control in fields where the turning radius tends to be small. The technology described in Patent Document 3 above is steering control for straight-line driving by processing an image of the ground on which the vehicle is driving, including the distant view in front of the vehicle, and therefore cannot be applied to control during turns. [Prior art documents]

Patent Documents

[0009]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0010] The present invention has been made to solve the above problems, and even when performing learning running control of a work vehicle based on a teaching route with a relatively small turning radius, it is an object to suppress steering vibration in the left-right direction and enable stable running.

Means for Solving the Problems

[0011] In order to solve the above problems, in the present invention, when performing learning running in which a plurality of teaching points acquired by the teaching running of a work vehicle are sequentially set as target points to control the running of the work vehicle, the position information of the plurality of teaching points recorded during the teaching running and the traveling direction of the work vehicle at the plurality of teaching points (referred to as the teaching point traveling direction Φt) are acquired, and the current position and traveling direction of the work vehicle during learning running (referred to as the current traveling direction Φc) are acquired. A first calculation angle θd for correcting the current traveling direction Φc of the work vehicle to the direction from the current position to the current target point (referred to as the current target direction Φd), and a second calculation angle θt for correcting the current traveling direction Φc of the work vehicle to the teaching point traveling direction Φt at the teaching point that is the current target point are calculated. Then, based on a predetermined function having the first calculation angle θd and the second calculation angle θt as explanatory variables, the control steering angle θf of the current position of the work vehicle is calculated, and the steering of the work vehicle is controlled according to the calculated control steering angle θf.

Effects of the Invention

[0012] According to the present invention configured as described above, not only is a first calculation angle θd calculated to correct the current direction of travel Φc of the work vehicle to the current target direction Φd, but a second calculation angle θt is also calculated to correct the current direction of travel Φc of the work vehicle to the direction of travel Φt of the training point, and the control steering angle θf is calculated based on the first calculation angle θd and the second calculation angle θt. For this reason, even if the first calculation angle θd becomes quite large, for example, during turns in training runs, the increase in the control steering angle θf is mitigated by taking the second calculation angle θt into account when calculating the control steering angle θf, and the occurrence of a large, steep steering angle control due to a very large control steering angle θf is suppressed. As a result, even when training runs of a work vehicle are controlled based on a training path with a relatively small turning radius, lateral steering vibrations can be suppressed and stable driving can be achieved. [Brief explanation of the drawing]

[0013] [Figure 1] This figure shows an example of the hardware configuration of a vehicle control system to which the driving control device according to this embodiment is applied. [Figure 2] This is an explanatory diagram of the terms and symbols used in this embodiment. [Figure 3] This is a block diagram showing an example of the functional configuration of the main control unit (driving control device) according to this embodiment. [Figure 4] This figure shows an example of setting a target point using the target point setting unit of this embodiment. [Figure 5] This figure illustrates the operation of steering control based on the control steering angle calculated by the linear function of this embodiment. [Figure 6A] This flowchart shows an example of the operation of the main control unit (driving control device) according to this embodiment. [Figure 6B] This flowchart shows an example of the operation of the main control unit (driving control device) according to this embodiment. [Figure 7] This flowchart shows another example of operation of the main control unit (driving control device) according to this embodiment. [Figure 8]This figure shows an example of setting the weight coefficient and gain coefficient in the linear function of this embodiment. [Figure 9] This is a diagram to explain the conventional problems. [Modes for carrying out the invention]

[0014] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. Figure 1 is a diagram showing an example of the hardware configuration of a vehicle control system to which the driving control device according to this embodiment is applied. As shown in Figure 1, the vehicle control system of this embodiment comprises a main control unit 1, a training data storage unit 2, an input / output control unit 3, a GNSS sensor 4, a steering sensor 5, and a steering actuator 6. The main control unit 1, the training data storage unit 2, the input / output control unit 3, and the GNSS sensor 4 are connected by a CAN (Controller Area Network) communication bus 7. The steering sensor 5 and the steering actuator 6 are connected to the input / output control unit 3.

[0015] The main control unit 1 sets either a teacher driving mode or a trainee driving mode and performs control according to the set mode. When the teacher driving mode is set, the main control unit 1 acquires data on the teacher route traveled by the operator manually driving the work vehicle and data on the status of the work vehicle, and records it as teacher data in the teacher data storage unit 2. That is, the main control unit 1 sequentially inputs the data detected by the GNSS sensor 4 and the steering sensor 5 when the work vehicle is manually driven, and records the input data as teacher data in the teacher data storage unit 2.

[0016] The GNSS sensor 4 is a sensor that detects the current position and direction of a moving work vehicle. The GNSS sensor 4 is configured, for example, with a GPS (Global Positioning System) receiver, and receives radio waves transmitted from multiple GPS satellites with a GPS antenna, and performs 3D positioning processing or 2D positioning processing to detect the absolute position and absolute direction of the work vehicle. The current position and direction data detected by the GNSS sensor 4 (hereinafter referred to as current position / direction data) is supplied to the main control unit 1 via the communication bus 7, and is recorded in the training data storage unit 2 as training data under the control of the main control unit 1.

[0017] For example, while a worker is manually driving a work vehicle around a field and performing agricultural work, the GNSS sensor 4 sequentially detects the current position and direction of the work vehicle at regular time intervals, and the detected current position and direction data is sequentially supplied to the main control unit 1 via the communication bus 7. The main control unit 1 uses all or some of the multiple vehicle positions indicated by the sequentially input current position data as training points on the training path, and records the position information of the training points in the training data storage unit 2. The main control unit 1 also records the direction of travel information of the work vehicle at multiple training points indicated by the sequentially input current direction data (information representing the training point direction of travel Φt, described later) in the training data storage unit 2 in association with the position information of the training points.

[0018] The steering sensor 5 is a sensor that detects the steering angle of the drive wheels (at least one of the front and rear wheels) of a moving work vehicle. The steering angle data detected by the steering sensor 5 (hereinafter referred to as steering angle data) is supplied to the main control unit 1 via the input / output control unit 3 and the communication bus 7, and is recorded in the training data storage unit 2 as training data under the control of the main control unit 1.

[0019] For example, while a worker is manually driving a work vehicle around a field and performing agricultural work, the steering sensor 5 sequentially detects the steering angle at regular time intervals, and the detected steering angle data is sequentially supplied to the main control unit 1. The main control unit 1 records the steering angle information of the work vehicle at multiple training points indicated by the sequentially input steering angle data (information representing the training point steering angle θa, described later) in the training data storage unit 2, associating it with the position information of the training points.

[0020] When the training mode is set, the main control unit 1 sequentially sets a plurality of training points recorded in the training data storage unit 2 by the training vehicle's training run as target points for training run, according to the current position of the training vehicle detected by the GNSS sensor 4, and controls the training vehicle to train towards the sequentially set target points. Specifically, the main control unit 1 calculates the steering control amount for the current steering angle detected by the steering sensor 5, and controls the steering of the training vehicle's drive wheels by driving the steering actuator 6 according to the calculated steering control amount. The main control unit 1 that performs this control corresponds to the driving control device in this embodiment. Details of the control content during training run performed by the main control unit 1 (driving control device) will be described later.

[0021] To explain the control process during the training run, we will first define the terms and symbols using Figure 2. Let T(Xm,Ym) be the multiple training points on the training path TR, and C(Xn,Yn) be the current position of the work vehicle on the training run trajectory VP. Here, (X,Y) are position coordinate values ​​in the UTM plane coordinate system and are determined based on the detection data of the GNSS sensor 4. The multiple training points T on the training path TR are sequentially set as multiple target points during the training run. In the following explanation, the target point set during the training run from among the multiple training points T will be denoted as Tt.

[0022] Let the direction of travel of the work vehicle at multiple training points T on the training path TR be "training point direction of travel Φt", and the vector pointing from training point T towards the training point direction of travel Φt be "training point direction vector Vt". Let the steering angle of the work vehicle at multiple training points T be "training point steering angle θa", and the vector pointing from training point T towards the training point steering angle θa be "training point steering angle vector Va". Let the direction of travel of the work vehicle at the vehicle's current position C on the training trajectory VP be "current direction of travel Φc", and the vector pointing from the vehicle's current position C towards the current direction of travel Φc be "current direction vector Vc". Note that the direction of travel of the work vehicle is defined as 0° for north (N), + for clockwise, and - for counterclockwise, and the steering angle is defined as + for right turns and - for left turns. The units for direction and steering angle are both in degrees [°].

[0023] Let "Current Target Direction Φd" be the direction from the vehicle's current position C to the current target point Tt, and "Current Target Vector Vd" be the vector pointing from the vehicle's current position C towards this current target direction Φd. The current target direction Φd is calculated as follows. Φd = 270 - tan -1 {(Ym-Yn) / (Xm-Xn)}(Xm <Xnのとき) = 90 - tan -1 {(Ym-Yn) / (Xm-Xn)} (Xn <Xmのとき)

[0024] Let L [m] be the distance from the vehicle's current position C to the current target point Tt, and let LG be the square of this distance L (hereinafter referred to as the local gap). In the following explanation, if there is no particular distinction between the distance L from the vehicle's current position C to the current target point Tt and the local gap LG (for example, if either can be used), it will be written as "distance L, LG". The local gap LG is calculated as follows. LG = (Xm - Xn) 2 +(Ym-Yn) 2

[0025] Let θd be the angle between the current direction vector Vc and the current target vector Vd, and let θt be the angle between the current direction vector Vc and the target point direction vector Vt of the target point T (hereinafter referred to as the target point direction vector Vtt). Both angles θd and θt are angles in the right turn direction or left turn direction relative to the current direction vector Vc. As will be explained in more detail later, θd corresponds to the first calculation angle for correcting the current direction of the work vehicle Φc to the current target direction Φd. Also, θt corresponds to the second calculation angle for correcting the current direction of travel Φc to the target point direction of travel Φt at the target point T (hereinafter referred to as the target point direction of travel Φtt).

[0026] Let θf be the control steering angle of the work vehicle's current position, and let Vf be the control steering vector, which is the vector in the direction the work vehicle moves from its current position C according to the control steering angle θf. In this embodiment, the control steering angle θf is calculated by the linear function shown in equation (1) below, which is obtained by multiplying the linear sum of the first operation angle θd and the second operation angle θt, weighted by their respective weight coefficients kd and kt, by the gain coefficient K. θf=K(kt×θt+kd×θd)...Equation (1)

[0027] Figure 3 is a block diagram showing an example of the functional configuration of the main control unit 1 (driving control device) according to this embodiment. As shown in Figure 3, the driving control device of this embodiment has the following functional configuration: a teacher driving information acquisition unit 11, a current driving information acquisition unit 12, a target point setting unit 13, a calculation angle calculation unit 14, a control steering angle calculation unit 15, and a steering control unit 16.

[0028] The above-described functional blocks 11 to 16 perform the processes described below through the cooperation of hardware and software. For example, the processes of functional blocks 11 to 16 are executed by the operation of programs stored in storage media such as RAM, ROM, hard disk, or semiconductor memory, under the control of a processor configured by a microcomputer equipped with a CPU, RAM, ROM, etc. In addition to the microcomputer, a DSP (Digital Signal Processor) may also be provided.

[0029] The teacher driving information acquisition unit 11 acquires information about the teacher route TR and the status of the work vehicle recorded in the teacher data storage unit 2 during teacher driving. The information acquired by the teacher driving information acquisition unit 11 includes the position information (Xm, Ym) of multiple teacher points T, the direction of travel of the work vehicle at multiple teacher points T (teacher point direction of travel Φt), and the steering angle of the work vehicle at multiple teacher points T (teacher point steering angle θa). For example, the teacher driving information acquisition unit 11 acquires the above information regarding multiple teacher points T from the teacher data storage unit 2 all at once and stores it in memory. Alternatively, it may sequentially acquire information about the teacher point T to be set as the target point Tt from among the multiple teacher points T and store it in memory.

[0030] The current driving information acquisition unit 12 acquires information regarding the practice driving trajectory VP and the status of the work vehicle during practice driving. The information acquired by the current driving information acquisition unit 12 is the current position C(Xn,Yn) of the work vehicle, the direction of travel of the work vehicle at the current position C (current direction of travel Φc), and the current steering angle detected by the steering sensor 5. The current position C(Xn,Yn) and the current direction of travel Φc are determined based on detection data acquired from the GNSS sensor 4. The current driving information acquisition unit 12 sequentially acquires the current position C(Xn,Yn), the current direction of travel Φc, and the current steering angle at regular time intervals.

[0031] The target point setting unit 13 sequentially sets multiple teacher points T as target points Tt in accordance with the progress of the work vehicle. At the start of the training run, the target point setting unit 13 initially sets the teacher point T closest to the starting point of the teacher route TR as the current target point Tt. Subsequently, when the distance L,LG between the current vehicle position C and the current target point Tt falls below a distance threshold, the target point setting unit 13 updates the current target point Tt to the next target point Tt using a teacher point T located beyond the current target point Tt.

[0032] Figure 4 shows an example of setting a target point Tt by the target point setting unit 13. The target point setting unit 13 sets multiple target points T in accordance with the continuously changing current vehicle position C.-1 , T -2 , T -3 , ··· are sequentially set as the target point Tt. For example, when the work vehicle is at the current position C -1 , C -2 , the teaching point T -3 is set as the current target point Tt. The vehicle current position C -1 , C -2 and the distance L, LG between the current target point Tt are greater than or equal to the distance threshold. In contrast, when the work vehicle advances to the vehicle current position C -3 , the distance L, LG between the vehicle current position C -3 and the current target point Tt becomes less than the distance threshold. Therefore, the target point setting unit 13 sets the teaching point T -3 (one step ahead of the current target point Tt (teaching point T -4 )) as the next target point Tt. The vehicle current position C -1 , C -2 at, the teaching point T -3 is set as the current target point Tt, while at the vehicle current position C -3 , the teaching point T -4 is set as the current target point Tt.

[0033] Here, the distance threshold that triggers the switching of the target point Tt may be a fixed value, but it can also be a variable value. For example, the target point setting unit 13 may variably set the distance threshold according to the absolute value of the teaching point steering angle θa (hereinafter referred to as the target point steering angle θat) at the teaching point T set as the current target point Tt. For example, when it is assumed that the work vehicle is traveling straight and the absolute value |θat| of the target point steering angle is less than the angle threshold (for example, 10°), the distance threshold to be set may be made larger than the distance threshold to be set when it is assumed that the work vehicle is turning and the absolute value |θat| of the target point steering angle is greater than or equal to the angle threshold. As an example, when |θat| < 10°, the distance threshold for the local gap LG may be set to 0.9, and when |θat| ≥ 10°, the distance threshold for the local gap LG may be set to 0.5.

[0034] Furthermore, the target point setting unit 13 may set multiple distance thresholds when it is assumed that the work vehicle is traveling in a straight line and the absolute value of the current target point steering angle |θat| is less than the angle threshold, and vary the teacher point T to be set for the next target point Tt according to the distance threshold that the distance L,LG between the current vehicle position C and the current target point Tt falls below. For example, a first distance threshold, a second distance threshold, and a third distance threshold may be set, and the teacher point T to be set for the next target point Tt may be varied according to which distance threshold L,LG falls below. On the other hand, when it is assumed that the work vehicle is traveling in a turning direction and the absolute value of the current target point steering angle |θat| is greater than or equal to the angle threshold, there is only one distance threshold.

[0035] For example, if the absolute value of the current target point steering angle |θat| is less than 10° (assuming the vehicle is driving in a straight line), when LG < 0.1, the next target point Tt is set to the teacher point T three positions ahead of the current target point Tt. If 0.1 ≤ LG < 0.3, the next target point Tt is set to the teacher point T two positions ahead of the current target point Tt. If 0.3 ≤ LG < 0.9, the next target point Tt is set to the teacher point T one position ahead of the current target point Tt. In this way, if the beginning of the teacher path TR is a straight path, the target point Tt may be set to the teacher point T two or three positions ahead at the start of the training run. On the other hand, if the absolute value of the current target point steering angle |θat| is 10° or more (assuming the vehicle is driving in a turn), when LG < 0.5, the next target point Tt is set to the teacher point T one position ahead of the current target point Tt.

[0036] The calculation angle calculation unit 14 calculates a first calculation angle θd to correct the current direction of travel Φc of the work vehicle to the current target direction Φd, and a second calculation angle θt to correct the current direction of travel Φc of the work vehicle to the direction of travel Φtt of the target point.

[0037] Here, the first operation angle θd is calculated as the angle between the current target vector Vd and the current moving vector Vc. Specifically, the first operation angle θd is calculated by the following formula. θd = Φd - Φc + 360 (when Φd - Φc < -180) =Φd-Φc (when -180≦Φd-Φc≦180) =Φd-Φc-360 (when Φd-Φc>180) In the scenario illustrated in Figure 2, the first angle of operation θd in the leftward turning direction is calculated from the current direction vector Vc using the formula θd = Φd - Φc - 360.

[0038] Furthermore, the second calculation angle θt is calculated as the angle between the current vector Vc and the target point vector Vtt, with Vc as the reference. Specifically, the second calculation angle θt is calculated by the following formula. θt = Φtt - Φc + 360 (when Φtt - Φc < -180) =Φtt-Φc (when -180≦Φtt-Φc≦180) =Φtt-Φc-360 (when Φtt-Φc>180) In the scenario illustrated in Figure 2, the second angle of operation θt in the rightward turn direction is calculated from the current direction vector Vc using the formula θt = Φtt - Φc.

[0039] The control steering angle calculation unit 15 calculates the control steering angle θf of the drive wheels of the work vehicle at the current vehicle position C based on a predetermined function that uses the first calculation angle θd and the second calculation angle θt calculated by the calculation angle calculation unit 14 as explanatory variables. As described above, the control steering angle calculation unit 15 calculates the control steering angle θf using the linear function shown in equation (1). The control steering angle calculation unit 15 calculates the control steering angle θf at predetermined time intervals (for example, every 100 msec).

[0040] Figure 5 is a diagram illustrating the operation of steering control based on the control steering angle θf calculated by equation (1). Figure 5(a) shows the state where the current direction vector Vc and the target point direction vector Vtt are pointing in the same direction. In this state, the second calculation angle θt is 0°, so equation (1) becomes θf = K(kd × θd), and the control steering angle θf is calculated based only on the first calculation angle θd, which corrects the current direction Φc to the current target direction Φd.

[0041] Figure 5(b) shows the state where the current direction vector Vc and the current target vector Vd are pointing in the same direction. In this state, the first operating angle θd is 0°, so equation (1) becomes θf = K(kt × θt), and the control steering angle θf is calculated based only on the second operating angle θt, which corrects the current direction Φc to the target point direction Φtt.

[0042] Figure 5(c) shows other states that do not correspond to either Figure 5(a) or Figure 5(b). In this state, the control steering angle θf is calculated by the linear function of equation (1), which takes into account both the first operating angle θd and the second operating angle θt. In the state shown in Figure 5(c), the first operating angle θd and the second operating angle θt are steering angles in opposite directions with respect to the current heading Φc. Therefore, even when the first operating angle θd is quite large, it is possible to mitigate the increase in the control steering angle θf and suppress the occurrence of steep large rudder angle control.

[0043] As shown in Figure 5(c), when the work vehicle is turning and is traveling from outside the center of rotation of the turn toward the teacher path TR, the first calculation angle θd is a steering angle in the left direction from the current direction of travel Φc toward the target point Tt, while the second calculation angle θt is a steering angle in the right direction from the current direction of travel Φc toward the opposite direction from the target point Tt. Thus, the first calculation angle θd and the second calculation angle θt are steering angles in opposite directions relative to the current direction of travel Φc.

[0044] In the state shown in Figure 5(c), the first calculation angle θd used to correct the current heading Φc of the work vehicle to the current target heading Φd may be a relatively large value. In this case, if the steering of the work vehicle is controlled using the large first calculation angle θd as the control steering angle θf, a steep large steering angle control will be performed, which may cause steering vibrations in which the learned travel trajectory VP sways from side to side relative to the teacher path TR.

[0045] In contrast, in this embodiment, the control steering angle θf is calculated using the linear function of equation (1), which also takes into account the second calculation angle θt used to correct the current direction of travel Φc of the work vehicle to the direction of travel Φtt of the target point. Therefore, even when the first calculation angle θd becomes quite large, the second calculation angle θt, which is in the opposite direction to the first calculation angle θd, is reflected in the calculation of the control steering angle θf, mitigating the increase in the control steering angle θf and preventing the use of steep, large steering angle control.

[0046] Although not shown in Figure 5, when the work vehicle is turning and is traveling from inside the teacher path TR relative to the center of rotation of the turn, the first calculation angle θd is a steering angle in the right direction, moving from the current direction of travel Φc towards the target point Tt, while the second calculation angle θt is a steering angle in the left direction, moving in the opposite direction from the target point Tt. Thus, the first calculation angle θd and the second calculation angle θt are steering angles in opposite directions relative to the current direction of travel Φc. In this case as well, the second calculation angle θt, which is in the opposite direction to the first calculation angle θd, is reflected in the calculation of the control steering angle θf, which mitigates the increase in the control steering angle θf and makes it possible to suppress the occurrence of steep large steering angle control.

[0047] In the linear function of equation (1), the weight coefficient kd for the first operation angle θd, the weight coefficient kt for the second operation angle θt, and the gain coefficient K for the linear sum may all be fixed values, but it is also possible to make at least one of the weight coefficients kd, kt, and the gain coefficient K a variable value. If all are fixed values, for example, kd=kt=0.75 and K=0.5 can be used.

[0048] When the weight coefficients kd and kt are variable values, for example, the control steering angle calculation unit 15 may change the weight coefficients kd and kt according to the distance L and LG between the current vehicle position C and the current target point Tt. By making the weight coefficients kd and kt variable values ​​according to the distance L and LG, it becomes possible to appropriately set the weight coefficients kd and kt according to situations such as when the current vehicle position C approaches the current target point Tt as the work vehicle moves and the distance L and LG decreases, or when the current target point Tt is updated to the next target point Tt and the distance L and LG increases.

[0049] For example, when the distance L,LG between the current vehicle position C and the current target point Tt is relatively large, the first calculation angle θd and the second calculation angle θt may be weighted equally, while as the distance L,LG decreases, the weighting of the first calculation angle θd may be reduced compared to the second calculation angle θt to calculate the control steering angle θf. As an example, the weight coefficients kd and kt may be changed as follows depending on the size of the local gap LG. When LG < 0.1: kd = 0.3, kt = 1.2 When 0.1 ≤ LG < 0.3: kd = 0.5, kt = 1.0 When 0.3 ≤ LG: kd = 0.75, kt = 0.75

[0050] In this way, when the distance L,LG between the vehicle's current position C and the current target point Tt is relatively large (when 0.3 ≤ LG), the degree to which the first calculation angle θd, which corrects the work vehicle's current direction of travel Φc to the current target direction Φd, and the second calculation angle θt, which corrects the work vehicle's current direction of travel Φc to the target point direction of travel Φtt, influence the calculation of the control steering angle θf is made equal, thereby improving tracking performance. On the other hand, as the vehicle's current position C approaches the current target point Tt, the degree to which the first calculation angle θd influences the calculation of the control steering angle θf decreases, making it possible to suppress the application of steep, large steering angle control relative to the teacher path TR.

[0051] When the gain coefficient K is a variable value, for example, the control steering angle calculation unit 15 may set the gain coefficient K to be variable according to the absolute value |θat| of the current target point steering angle. By making the gain coefficient K a variable value according to the absolute value |θat| of the target point steering angle, when sequentially setting multiple teacher points T set on the teacher path TR to target points Tt and controlling the work vehicle to learn driving, it becomes possible to appropriately set the gain coefficient K in accordance with the actual steering angle (size of the turning radius) during teacher driving.

[0052] For example, the gain coefficient K set when it is assumed that the work vehicle is turning with the absolute value of the target point steering angle |θat| being greater than or equal to an angular threshold (e.g., 10°) may be set to be greater than the gain coefficient K set when it is assumed that the work vehicle is traveling in a straight line with the absolute value of the target point steering angle |θat| being less than the angular threshold. As an example, K may be set to 0.5 when |θat| < 10° and to 0.53 when |θat| ≥ 10°. In this way, the gain coefficient K is larger when turning than when traveling in a straight line, which improves the ability to follow the teacher path TR when turning.

[0053] Furthermore, if the angle threshold described above is used as the first angle threshold, a larger second angle threshold may be used, and the gain coefficient K set when it is assumed that the work vehicle is making a sharp turn when the absolute value of the target point steering angle |θat| is greater than or equal to the second angle threshold (e.g., 20°) may be set to be greater than the gain coefficient K set when it is assumed that the work vehicle is not making a sharp turn when the absolute value of the target point steering angle |θat| is less than the second angle threshold. For example, K may be set to 0.53 when 10°≦|θat|<20°, and to 0.55 when |θat|≧20°. Doing so makes it possible to improve the ability to follow the teacher path TR when a sharp turn is occurring.

[0054] The steering control unit 16 controls the steering of the work vehicle according to the control steering angle θf calculated by the control steering angle calculation unit 15. For example, the steering control unit 16 calculates a steering control amount based on the difference between the control steering angle θf calculated by the control steering angle calculation unit 15 and the current steering angle detected by the steering sensor 5, and controls the steering of the drive wheels of the work vehicle by outputting a steering command to drive the steering actuator 6 according to the calculated steering control amount.

[0055] The control steering angle calculation unit 15 calculates the control steering angle θf at predetermined intervals, while the steering control unit 16 outputs a steering command to the input / output control unit 3 according to the control steering angle θf at predetermined travel distances of the work vehicle, thereby driving the steering actuator 6. Here, the steering control unit 16 may set the predetermined travel distance variably according to the absolute value |θat| of the current target point steering angle. For example, when the absolute value |θat| of the target point steering angle is less than a first angle threshold (e.g., 10°) and it is assumed that the work vehicle is traveling in a straight line, a steering command may be output every 0.5 [m] travel, while when the absolute value |θat| of the target point steering angle is greater than or equal to the first angle threshold and it is assumed that the work vehicle is traveling in a turning direction, a steering command may be output every 0.2 [m] travel.

[0056] Figures 6A and 6B are flowcharts showing an example of the operation of the main control unit 1 having the functional configuration shown in Figure 3 (an example of a processing procedure for the driving control method). The processing in the flowcharts shown in Figures 6A and 6B is repeatedly executed at predetermined intervals (for example, every 100 msec).

[0057] In Figure 6A, first, the target point setting unit 13 initializes the current target point Tt with the teacher point T closest to the starting point of the teacher route TR (step S1). Next, the teacher driving information acquisition unit 11 acquires information about the teacher point T (position coordinates of the teacher point T, direction of travel Φt of the teacher point, steering angle θa of the teacher point, etc.), and the current driving information acquisition unit 12 acquires information about the current position C of the work vehicle (position coordinates of the current position C, direction of travel Φc, steering angle, etc.), and the target point setting unit 13 calculates the local gap LG between the current position C of the vehicle and the current target point Tt (step S2). Then, the main control unit 1 determines whether the absolute value of the current target point steering angle |θat| is less than 10° (step S3). If |θat|<10°, it is assumed that the work vehicle is driving in a straight line, and the processes in steps S4 to S19 shown in Figure 6A are executed.

[0058] In step S4, the main control unit 1 determines whether the local gap LG between the current vehicle position C and the current target point Tt is less than 0.1. If it is determined that LG < 0.1, the control steering angle calculation unit 15 sets the weight coefficients kd = 0.3 and kt = 1.2 (step S5).

[0059] If it is determined in step S4 that LG < 0.1, the main control unit 1 further determines whether the local gap LG is 0.1 or greater and less than 0.3 (step S6). If it is determined that 0.1 ≤ LG < 0.3, the control steering angle calculation unit 15 sets the weight coefficients kd = 0.5 and kt = 1.0 (step S7).

[0060] If it is determined in step S6 that 0.1 ≤ LG < 0.3 is not true, i.e., 0.3 ≤ LG, the control steering angle calculation unit 15 sets the weight coefficients kd = 0.75 and kt = 0.75 (step S8). After step S5, step S7, or step S8, the process proceeds to step S9.

[0061] In step S9, the control steering angle calculation unit 15 sets the gain coefficient to K=0.5. Then, in the next step S10, the calculation angle calculation unit 14 calculates the first calculation angle θd and the second calculation angle θt, and using the calculated first calculation angle θd and second calculation angle θt, the control steering angle calculation unit 15 calculates the control steering angle θf according to the linear function shown in equation (1). After that, the steering control unit 16 determines whether the work vehicle has moved 0.5m forward since the last time a steering command was output (step S11).

[0062] If it is determined that the work vehicle has moved 0.5m, the steering control unit 16 calculates the steering control amount according to the control steering angle θf most recently calculated by the control steering angle calculation unit 15 and outputs a steering command to the steering actuator 6 (step S12). On the other hand, if it is determined that the work vehicle has not yet moved 0.5m, the process in step S12 is skipped.

[0063] After processing in step S11 or step S12, the main control unit 1 determines whether the local gap LG is less than 0.1 (step S13). If it is determined that LG < 0.1, the target point setting unit 13 updates the current target point Tt to the next target point Tt using a teacher point T that is three positions ahead of the current target point Tt (step S14).

[0064] If it is determined in step S13 that LG < 0.1, the main control unit 1 further determines whether the local gap LG is 0.1 or greater and less than 0.3 (step S15). If it is determined that 0.1 ≤ LG < 0.3, the target point setting unit 13 updates the current target point Tt to the next target point Tt using a teacher point T that is two positions ahead of the current target point Tt (step S16).

[0065] If it is determined in step S15 that 0.1 ≤ LG < 0.3 is not true, the main control unit 1 further determines whether the local gap LG is 0.3 or greater and less than 0.9 (step S17). If it is determined that 0.3 ≤ LG < 0.9, the target point setting unit 13 updates the current target point Tt to the next target point Tt using the teacher point T that is one step ahead of the current target point Tt (step S18).

[0066] If it is determined in step S17 that 0.3 ≤ LG < 0.9 is not true, i.e., 0.9 ≤ LG, then the process in step S18 is skipped. In this case, the target point setting unit 13 maintains the current target point Tt and does not update it to the next target point Tt. After steps S14, S16, S17, or S18, the process proceeds to step S19.

[0067] In step S19, the main control unit 1 determines whether or not the farm work is completed. Here, it determines whether or not the driving control of the work vehicle has been performed by setting all the teacher points T on the teacher path TR to the target point Tt. If it is determined that the farm work is not yet completed, the process returns to step S2. On the other hand, if it is determined that the farm work is completed, the process of the flowcharts shown in Figures 6A and 6B is terminated.

[0068] In step S3 described above, if it is determined that |θat| < 10°, it is assumed that the work vehicle is turning, and the processes in steps S21 to S36 shown in Figure 6B are executed.

[0069] In step S21, the main control unit 1 determines whether the local gap LG is less than 0.1. If it is determined that LG < 0.1, the control steering angle calculation unit 15 sets the weight coefficients kd = 0.3 and kt = 1.2 (step S22).

[0070] If it is determined in step S21 that LG < 0.1, the main control unit 1 further determines whether the local gap LG is 0.1 or greater and less than 0.3 (step S23). If it is determined that 0.1 ≤ LG < 0.3, the control steering angle calculation unit 15 sets the weight coefficients kd = 0.5 and kt = 1.0 (step S24).

[0071] If it is determined in step S23 that 0.1 ≤ LG < 0.3 is not true, i.e., 0.3 ≤ LG, the control steering angle calculation unit 15 sets the weight coefficients kd = 0.75 and kt = 0.75 (step S25). After steps S22, S24, or S25, the process proceeds to step S26.

[0072] In step S26, the main control unit 1 determines whether the absolute value of the current target point steering angle |θat| is less than 20°. If |θat| < 20°, it is assumed that the work vehicle is not making a sharp turn, and the control steering angle calculation unit 15 sets the gain coefficient K = 0.5 (step S27). On the other hand, if |θat| ≥ 20°, it is assumed that the work vehicle is making a sharp turn, and the control steering angle calculation unit 15 sets the gain coefficient K = 0.55 (step S28).

[0073] After step S27 or step S28, the calculation angle calculation unit 14 calculates the first calculation angle θd and the second calculation angle θt, and the control steering angle calculation unit 15 calculates the control steering angle θf according to the linear function shown in equation (1) using the calculated first calculation angle θd and the second calculation angle θt (step S29). Then, the steering control unit 16 determines whether the work vehicle has moved 0.2m forward since the last time a steering command was output (step S30).

[0074] If it is determined that the work vehicle has moved 0.2m, the steering control unit 16 calculates the steering control amount according to the control steering angle θf most recently calculated by the control steering angle calculation unit 15 and outputs a steering command to the steering actuator 6 (step S31). On the other hand, if it is determined that the work vehicle has not yet moved 0.2m, the process in step S31 is skipped. After step S30 or step S31, the process proceeds to step S32.

[0075] In step S32, the main control unit 1 determines whether the local gap LG is less than 0.5. If it is determined that LG < 0.5, the target point setting unit 13 updates the current target point Tt to the next target point Tt using the teacher point T that is one position ahead of the current target point Tt (step S33).

[0076] If it is determined in step S32 that LG < 0.5, i.e., 0.5 ≤ LG, then the process in step S33 is skipped. In this case, the target point setting unit 13 maintains the current target point Tt and does not update to the next target point Tt. After step S32 or step S33, the process proceeds to step S34. In step S34, the main control unit 1 determines whether or not the farm work has been completed. If it is determined that the farm work has been completed, the process shown in the flowcharts in Figures 6A and 6B is terminated.

[0077] On the other hand, if it is determined that the farm work is not yet finished, the main control unit 1 determines whether the absolute value of the current target point steering angle |θat| is less than 5° (step S35). If it is determined that |θat|<5°, it is assumed that the work vehicle is traveling in a straight line, so the process returns to step S2 in Figure 6A. On the other hand, if it is determined that |θat|<5°, the teacher driving information acquisition unit 11 acquires information about the teacher point T, the current driving information acquisition unit 12 acquires information about the current position C of the work vehicle, and the target point setting unit 13 calculates the local gap LG (step S36). After that, the process returns to step S21 and continues with the turning driving process shown in Figure 6B.

[0078] Here, instead of determining whether the absolute value of the target point steering angle |θat| is less than 10° and returning to step S2, the system determines whether the absolute value of the target point steering angle |θat| is less than 5° and returns to step S2. In other words, the angle threshold when transitioning from the process during straight-line driving shown in Figure 6A to the process during turning driving shown in Figure 6B is set to 10°, while the angle threshold when transitioning from the process during turning driving shown in Figure 6B to the process during straight-line driving shown in Figure 6A is set to 5°.

[0079] In this way, the steering response is sensitive during the initial stage of straight-line driving after the turn is completed, as there is a section where the steering response from the turn is maintained (the section where the absolute value of the target point steering angle |θat| is 5° or more and less than 10°). Therefore, when transitioning from turn-line driving to straight-line driving, it is possible to quickly adjust to the driving control for the straight-line path. The angle threshold when transitioning from the processing during turn-line driving shown in Figure 6B to the processing during straight-line driving shown in Figure 6A may also be set to 10°.

[0080] As explained in detail above, in this embodiment, in addition to the first calculation angle θd for correcting the current direction of travel Φc of the work vehicle to the current target direction Φd, a second calculation angle θt for correcting the current direction of travel Φc of the work vehicle to the target point direction Φtt is also calculated, and the control steering angle θf is calculated based on the first calculation angle θd and the second calculation angle θt. Therefore, even when the first calculation angle θd becomes quite large during turns in training runs, the increase in the control steering angle θf is mitigated, and the occurrence of steep large steering angle control can be suppressed. As a result, even when training runs of the work vehicle are controlled based on a teacher path with a relatively small turning radius, lateral steering vibrations can be suppressed and stable driving can be achieved.

[0081] In the above embodiment, an example of calculating the control steering angle θf using the linear function shown in equation (1) was described, but the invention is not limited to this. For example, the control steering angle θf may be calculated using the linear function shown in equation (2) below, which does not use the gain coefficient K, that is, a linear function that adds the first operation angle θd and the second operation angle θt weighted by their respective weight coefficients kd and kt. For example, instead of setting the gain coefficient K to a fixed value, the linear function shown in equation (2) may be used. θf=kt×θt+kd×θd...Equation (2)

[0082] Furthermore, while the above embodiment describes an example in which the weighting coefficients kd and kt are changed according to the distances L and LG between the current vehicle position C and the current target point Tt, the embodiment is not limited to this. For example, in a section where turning is assumed to be occurring based on the absolute value |θat| of the target point steering angle, the weighting coefficients kd and kt may be changed according to the direction of travel Φt of each teacher point T.

[0083] As an example, the reference direction of travel Φt at a teacher point T (hereinafter referred to as the "turn start teacher point") when it is assumed that the absolute value of the steering angle of the teacher point |θa| exceeds a first angle threshold (e.g., 10°) and the turn has started is defined as the reference direction of travel Φt0. Furthermore, the direction of travel Φt at multiple teacher points T (hereinafter referred to as "turn-time teacher points") included up to the teacher point T (hereinafter referred to as the "turn end teacher point") when it is assumed that the turn has ended when the absolute value of the steering angle of the teacher point |θa| falls below the first angle threshold is defined as the direction of travel Φti (i>0). The control steering angle calculation unit 15 may change the weight coefficients kd and kt according to the magnitude of the azimuth difference |ΔΦt| between the reference direction of travel Φt0 and the direction of travel Φti during the period of learning by sequentially setting multiple turn-time teacher points to the target point Tt.

[0084] For example, the control steering angle calculation unit 15 may set the weight coefficients kd and kt variably during the learning period by sequentially setting multiple turning training points to the target point Tt, as shown below. When |ΔΦt|<50°: kd=0.75, kt=0.75 When 50°≦|ΔΦt|<90°: kd=1.0, kt=0.5 When 90°≦|ΔΦt|<120°: kd=1.2, kt=0.3 When 120° ≤ |ΔΦt|: kd = 0.5, kt = 1.0

[0085] Figure 7 is a flowchart showing an example of the operation performed during turning, which replaces the operation shown in Figure 6B. In the flowchart shown in Figure 7, steps S41 to S47 are performed instead of steps S21 to S25 shown in Figure 6B. Also, step S48 is performed instead of step S36 shown in Figure 6B.

[0086] In step S41, the main control unit 1 determines whether the bearing difference |ΔΦt| is less than 50°. If it is determined that |ΔΦt| < 50°, the control steering angle calculation unit 15 sets the weighting coefficients kd = 0.75 and kt = 0.75 (step S42).

[0087] In step S41, if it is determined that |ΔΦt| < 50°, the main control unit 1 further determines whether the bearing difference |ΔΦt| is 50° or greater and less than 90° (step S43). If it is determined that 50° ≤ |ΔΦt| < 90°, the control steering angle calculation unit 15 sets the weight coefficients kd = 1.0 and kt = 0.5 (step S44).

[0088] If it is determined in step S43 that 50° ≤ |ΔΦt| < 90° is not true, the main control unit 1 further determines whether the bearing difference |ΔΦt| is 90° or greater and less than 120° (step S45). If it is determined that 90° ≤ |ΔΦt| < 120°, the control steering angle calculation unit 15 sets the weighting coefficients kd = 1.2 and kt = 0.3 (step S46).

[0089] If it is determined in step S45 that 90° ≤ |ΔΦt| < 120° is not true, i.e., |ΔΦt| ≥ 120°, the control steering angle calculation unit 15 sets the weight coefficients kd = 0.5 and kt = 1.0 (step S47). After steps S42, S44, S46, or S47, the process proceeds to step S26. The processes in steps S26 to S35 have already been explained in Figure 6B, so a redundant explanation is omitted here.

[0090] If it is determined in step S35 that |θat| < 5°, the teacher driving information acquisition unit 11 acquires information about the teacher point T, and the current driving information acquisition unit 12 acquires information about the current position C of the work vehicle. Using this information, the target point setting unit 13 calculates the local gap LG, and the control steering angle calculation unit 15 calculates the bearing difference |ΔΦt| (step S48). After the processing in step S48, the process returns to step S41.

[0091] Figure 8 shows an example of setting the weight coefficients kd and kt when the weight coefficients kd and kt are set variably according to the azimuth difference |ΔΦt|. Figure 8 shows multiple training points T on the training path TR. -1 ~T -7 This also shows the set values ​​for the weight coefficients kd and kt, and the gain coefficient K.

[0092] In the example of leftward rotation shown in Figure 8, the target point T -1 At this point, |θat|≧10°, and the target point T -2 At this point, |θat|≧20°. Also, at the training point T -6 At this point, |θat| < 20°, and the target point T -7 At this point, |θat| < 5°. Therefore, the target point T -1 ~T -7 The training points up to the training point immediately preceding the current training point are the training points during rotation. Training point T -1 ~T -2 The previous teacher point, T -6 ~T -7 When the target point Tt is set, the gain coefficient K = 0.5, and the target point T -2 ~T -6When the previous training point is set as the target point Tt, the gain coefficient K = 0.55.

[0093] Furthermore, in the example shown in Figure 8, the training point T -3 At this point, |ΔΦt|≧50°, and the target point T -4 At this point, |ΔΦt|≧90°, and the target point T -5 At this point, |ΔΦt|≧120°. Therefore, the target point T -1 ~T -3 The previous teacher point, T -6 ~T -7 When the target point Tt is set, kd=0.75, kt=0.75, and the target point T -3 ~T -4 When the previous target point Tt is set, kd=1.0, kt=0.5, and target point T -4 ~T -5 When the previous training point is set as the target point Tt, kd=1.2, kt=0.3, and training point T -5 ~T -6 When the previous training point is set as the target point Tt, kd=0.5 and kt=1.0.

[0094] In this way, from the start of turning until the turning angle reaches 120°, the weighting coefficient kd for the first calculation angle θd gradually increases as the turning progresses, and the first calculation angle θd is mainly reflected in the calculation of the control steering angle θf. Furthermore, from the time the turning angle exceeds 120° until the turning is completed, the weighting coefficient kd for the first calculation angle θd is set to be smaller than the weighting coefficient kt for the second calculation angle θt, and the second calculation angle θt is mainly reflected in the calculation of the control steering angle θf.

[0095] This allows the tracking accuracy of the learned trajectory VP relative to the teacher path TR to gradually increase from the first half of the turn to the second half of the turn after transitioning from straight-line driving to turning driving, thereby suppressing the increasing discrepancy between the teacher path TR and the learned trajectory VP as the turn progresses (in the example shown in Figure 8, the outward bulge of the learned trajectory VP from the teacher path TR). Furthermore, in the section from the second half of the turn onward, the influence of the second calculation angle θt in the calculation of the steering angle θf becomes greater than that of the first calculation angle θd, allowing for a smooth transition from turning driving to straight-line driving.

[0096] Alternatively, the control steering angle calculation unit 15 may set the weight coefficients kd and kt variably as follows. That is, among the multiple turning teacher points described above, the teacher point T at which it is assumed that a sharp turn has started when the absolute value of the teacher point steering angle |θa| exceeds the second angle threshold (for example, 20°) is set as the sharp turn start teacher point. Also, the teacher point T at which it is assumed that a sharp turn has ended when the absolute value of the teacher point steering angle |θa| falls below the second angle threshold at a teacher point T after the sharp turn start teacher point is set as the sharp turn end teacher point. The control steering angle calculation unit 15 may then change the weight coefficients kd and kt according to the magnitude of the bearing difference |ΔΦt| described above during the period in which it is learning to drive by sequentially setting the multiple teacher points T (referred to as sharp turn teacher points) included between the sharp turn start teacher point and the sharp turn end teacher point as the target point Tt.

[0097] Furthermore, although the above embodiment describes an example in which the gain coefficient K is variably set according to the absolute value |θat| of the current target point steering angle, the system is not limited to this. For example, during teacher driving, the driving speed of the work vehicle at multiple teacher points T may be further recorded in the teacher data storage unit 2, the teacher driving information acquisition unit 11 may further acquire the driving speed of the work vehicle at the multiple teacher points T, and the control steering angle calculation unit 15 may variably set the gain coefficient K according to the driving speed of the work vehicle at the teacher point T which is set as the current target point Tt. For example, K may be set to 0.5 when the driving speed is above a threshold, and to 0.55 when it is below the threshold.

[0098] Alternatively, during the training run, the steering speed of the work vehicle at multiple training points T (the rate of change in steering angle between training points T) may be further recorded in the training data storage unit 2, the training run information acquisition unit 11 may further acquire the steering speed at the multiple training points T, and the control steering angle calculation unit 15 may variably set the gain coefficient K according to the steering speed of the work vehicle at the training point T designated as the current target point Tt. For example, K may be set to 0.5 when the steering speed is above a threshold, and to 0.55 when it is below the threshold.

[0099] The following is a summary of examples of configurations that can be applied to the driving control device of this embodiment.

[0100] [Configuration 1] A driving control device that sequentially sets multiple training points acquired by the training run of a work vehicle as target points for the training run of the work vehicle, and controls the work vehicle to perform a training run toward the sequentially set target points, A teacher driving information acquisition unit that acquires the positional information of the multiple teacher points recorded during the teacher driving and the direction of travel of the work vehicle at the multiple teacher points (teacher point direction of travel Φt), A current driving information acquisition unit acquires the current position of the work vehicle and the direction of travel of the work vehicle at that current position (current direction of travel Φc) during the above-mentioned practice driving, A target point setting unit that sequentially sets the above-mentioned multiple teaching points as target points in accordance with the progress of the above-mentioned work vehicle, An angle calculation unit calculates a first calculation angle θd for correcting the current direction of travel Φc of the work vehicle to a direction from the current position toward the current target point, and a second calculation angle θt for correcting the current direction of travel Φc of the work vehicle to the direction of travel Φt of the teacher point which is the current target point. A control steering angle calculation unit calculates the control steering angle θf of the current position of the work vehicle based on a predetermined function that uses the first calculation angle θd and the second calculation angle θt calculated by the above calculation angle calculation unit as explanatory variables, The system includes a steering control unit that controls the steering of the work vehicle according to the control steering angle θf calculated by the control steering angle calculation unit. A driving control device characterized by the following:

[0101] [Configuration 2] The driving control device according to configuration 1, characterized in that the predetermined function is a linear function that weights and adds the first operation angle θd and the second operation angle θt by their respective weight coefficients.

[0102] [Configuration 3] The travel control device according to configuration 1, characterized in that the predetermined function is a linear function that multiplies a linear sum obtained by weighting the first operation angle θd and the second operation angle θt by their respective weight coefficients, by a gain coefficient.

[0103] [Structure 4] The driving control device according to configuration 2 or 3, characterized in that the control steering angle calculation unit changes the weight coefficient according to the distance between the current position of the work vehicle and the current target point.

[0104] [Composition 5] The above-mentioned teacher driving information acquisition unit further acquires the steering angles of the work vehicle at the multiple teacher points recorded during the teacher driving (teacher point steering angle θa), The control steering angle calculation unit sets the following: the turning start teaching point where it is assumed that the absolute value |θa| of the steering angle of the teaching point exceeds the first angle threshold and the turning has started, is set as the reference direction of travel Φt0; the turning direction of travel Φti (i>0) is set as the direction of travel Φt of the teaching point at multiple turning teaching points included up to the turning end teaching point where it is assumed that the turning has ended because the absolute value |θa| of the steering angle of the teaching point falls below the first angle threshold at a teaching point after the turning start teaching point; and during the period in which the vehicle is learning by sequentially setting the multiple turning teaching points to the target point, the weighting coefficient is changed according to the magnitude of the difference between the reference direction of travel Φt0 and the direction of travel Φti. A driving control device according to any one of configurations 2 to 4, characterized in that...

[0105] [Composition 6] The control steering angle calculation unit described above sets a target point from among the plurality of turning target points where it is assumed that a sharp turn has started when the absolute value |θa| of the steering angle of the target point exceeds a second angle threshold which is greater than the first angle threshold, as the sharp turn start target point, and sets a target point after the sharp turn start target point where it is assumed that a sharp turn has ended when the absolute value |θa| of the steering angle of the target point falls below the second angle threshold, as the sharp turn end target point, and sequentially sets a plurality of sharp turn target points included between the sharp turn start target point and the sharp turn end target point as the target point, and changes the weight coefficient according to the magnitude of the difference between the reference direction of travel Φt0 and the direction of travel Φti during the learning drive period. This is the driving control device according to configuration 5.

[0106] [Composition 7] The above-mentioned teacher driving information acquisition unit further acquires the steering angles of the work vehicle at the multiple teacher points recorded during the teacher driving (teacher point steering angle θa), When the distance between the current position of the work vehicle and the current target point falls below a distance threshold, the target point setting unit updates the current target point to the next target point using a reference point located beyond the current target point. The target point setting unit variably sets the distance threshold according to the absolute value |θa| of the steering angle of the target point at the current target point. A driving control device according to any one of configurations 1 to 6, characterized by the above.

[0107] [Structure 8] The driving control device according to configuration 7, characterized in that the target point setting unit sets multiple distance thresholds when it is assumed that the work vehicle is traveling in a straight line and the absolute value |θa| of the steering angle of the current target point at the current target point is less than the first angle threshold, and the teacher point to be set as the next target point is varied according to the distance threshold that the distance between the current position of the work vehicle and the current target point falls below.

[0108] [Composition 9] The above-mentioned teacher driving information acquisition unit further acquires the steering angles of the work vehicle at the multiple teacher points recorded during the teacher driving (teacher point steering angle θa), The control steering angle calculation unit sets the gain coefficient variably according to the absolute value |θa| of the steering angle at the target point, which is the current target point. A driving control device according to any one of configurations 3 to 8, characterized by the above.

[0109] [Configuration 10] The above-mentioned teacher driving information acquisition unit further acquires the driving speed of the work vehicle at the multiple teacher points recorded during the above-mentioned teacher driving, The above-mentioned control steering angle calculation unit variably sets the gain coefficient according to the travel speed of the work vehicle at the current target point. A driving control device according to any one of configurations 3 to 8, characterized by the above.

[0110] [Composition 11] The above-mentioned teacher driving information acquisition unit further acquires the steering speeds at the multiple teacher points recorded during the above-mentioned teacher driving, The above-mentioned control steering angle calculation unit variably sets the gain coefficient according to the steering speed of the work vehicle at the current target point. A driving control device according to any one of configurations 3 to 4, characterized in that...

[0111] [Composition 12] The above-mentioned teacher driving information acquisition unit further acquires the steering angles of the work vehicle at the multiple teacher points recorded during the teacher driving (teacher point steering angle θa), The steering control unit outputs a steering command according to the control steering angle θf for each predetermined distance traveled by the work vehicle. The steering control unit sets the predetermined travel distance variably according to the absolute value |θa| of the steering angle at the current target point. A driving control device according to any one of configurations 1 to 11, characterized by the above.

[0112] Furthermore, the above embodiments are merely examples of how the present invention may be implemented, and the technical scope of the invention should not be interpreted as being limited by them. In other words, the present invention can be implemented in various ways without departing from its gist or its main features. [Explanation of Symbols]

[0113] 1. Main control unit (driving control device) 2. Training Data Storage Unit 3 Input / Output Control Unit 4 GNSS sensors 5. Steering sensor 6. Steering Actuator 7 Communications Bus 11. Teacher Driving Information Acquisition Unit 12 Current Driving Information Acquisition Unit 13. Target Point Setting Section 14 Arithmetic angle calculation section 15 Control steering angle calculation unit 16 Steering Control Unit

Claims

1. A driving control device that sequentially sets multiple training points acquired by the training run of a work vehicle as target points for the training run of the work vehicle, and controls the work vehicle to perform a training run toward the sequentially set target points, A teacher driving information acquisition unit that acquires the positional information of the multiple teacher points recorded during the teacher driving and the direction of travel of the work vehicle at the multiple teacher points (hereinafter referred to as the teacher point direction of travel Φt), A current driving information acquisition unit acquires the current position of the work vehicle and the direction of travel of the work vehicle at the current position (hereinafter referred to as the current direction of travel Φc) during the above-mentioned practice driving, A target point setting unit that sequentially sets the above-mentioned multiple teaching points as target points in accordance with the progress of the above-mentioned work vehicle, A calculation angle calculation unit calculates a first calculation angle θd for correcting the current direction of travel Φc of the work vehicle to a direction from the current position toward the current target point, and a second calculation angle θt for correcting the current direction of travel Φc of the work vehicle to the direction of travel Φt of the teacher point which is the current target point. A control steering angle calculation unit calculates the control steering angle θf of the current position of the work vehicle based on a predetermined function that uses the first calculation angle θd and the second calculation angle θt calculated by the above calculation angle calculation unit as explanatory variables, The system includes a steering control unit that controls the steering of the work vehicle according to the control steering angle θf calculated by the control steering angle calculation unit. A driving control device characterized by the following:

2. The driving control device according to claim 1, characterized in that the predetermined function is a linear function that weights and adds the first operation angle θd and the second operation angle θt by their respective weight coefficients.

3. The travel control device according to claim 1, characterized in that the predetermined function is a linear function that multiplies a linear sum obtained by weighting the first operation angle θd and the second operation angle θt by their respective weight coefficients, by a gain coefficient.

4. The driving control device according to claim 2 or 3, characterized in that the control steering angle calculation unit changes the weight coefficient according to the distance between the current position of the work vehicle and the current target point.

5. The above-mentioned teacher driving information acquisition unit further acquires the steering angles of the work vehicle at the multiple teacher points recorded during the teacher driving (hereinafter referred to as the teacher point steering angle θa), The control steering angle calculation unit sets the following: the turning start teaching point where it is assumed that the absolute value |θ|a of the steering angle of the teaching point exceeds the first angle threshold and the turning has started, is set as the reference direction of travel Φt0; the turning direction of travel Φt at the multiple turning teaching points included up to the turning end teaching point where it is assumed that the absolute value |θa| of the steering angle of the teaching point falls below the first angle threshold and the turning has ended, is set as the turning direction of travel Φti (i > 0); and during the period in which the multiple turning teaching points are sequentially set to the target point and the vehicle is learning to move, the weighting coefficient is changed according to the magnitude of the difference between the reference direction of travel Φt0 and the turning direction of travel Φti. The driving control device according to claim 2 or 3.

6. The control steering angle calculation unit described above sets a target point from among the plurality of turning target points where it is assumed that a sharp turn has started when the absolute value |θa| of the steering angle of the target point exceeds a second angle threshold which is greater than the first angle threshold, as the sharp turn start target point, and sets a target point at a point after the sharp turn start target point where it is assumed that a sharp turn has ended when the absolute value |θa| of the steering angle of the target point falls below the second angle threshold, as the sharp turn end target point, and sequentially sets a plurality of sharp turn target points included between the sharp turn start target point and the sharp turn end target point as the target point, and changes the weight coefficient according to the magnitude of the difference between the reference direction of travel Φt0 and the direction of travel Φti during the learning drive period, as described in claim 5.

7. The above-mentioned teacher driving information acquisition unit further acquires the steering angles of the work vehicle at the multiple teacher points recorded during the teacher driving (hereinafter referred to as the teacher point steering angle θa), When the distance between the current position of the work vehicle and the current target point falls below a distance threshold, the target point setting unit updates the current target point to the next target point using a reference point located beyond the current target point. The target point setting unit variably sets the distance threshold according to the absolute value |θa| of the steering angle of the target point at the current target point. A driving control device according to any one of claims 1 to 3.

8. The driving control device according to claim 7, characterized in that the target point setting unit sets multiple distance thresholds when it is assumed that the work vehicle is traveling in a straight line and the absolute value |θa| of the steering angle of the teaching point at the teaching point set as the current target point is less than the first angle threshold, and the teaching point to be set as the next target point is varied according to the distance threshold that the distance between the current position of the work vehicle and the current target point falls below.

9. The above-mentioned teacher driving information acquisition unit further acquires the steering angles of the work vehicle at the multiple teacher points recorded during the teacher driving (hereinafter referred to as the teacher point steering angle θa), The control steering angle calculation unit sets the gain coefficient variably according to the absolute value |θa| of the steering angle at the target point, which is the current target point. The driving control device according to claim 3.

10. The above-mentioned teacher driving information acquisition unit further acquires the driving speed of the work vehicle at the multiple teacher points recorded during the above-mentioned teacher driving, The above-mentioned control steering angle calculation unit variably sets the gain coefficient according to the travel speed of the work vehicle at the current target point. The driving control device according to claim 3.

11. The above-mentioned teacher driving information acquisition unit further acquires the steering speeds at the multiple teacher points recorded during the above-mentioned teacher driving, The above-mentioned control steering angle calculation unit variably sets the gain coefficient according to the steering speed of the work vehicle at the current target point. The driving control device according to claim 3.

12. The above-mentioned teacher driving information acquisition unit further acquires the steering angles of the work vehicle at the multiple teacher points recorded during the teacher driving (hereinafter referred to as the teacher point steering angle θa), The steering control unit outputs a steering command according to the control steering angle θf for each predetermined distance traveled by the work vehicle. The steering control unit sets the predetermined travel distance variably according to the absolute value |θa| of the steering angle at the current target point. A driving control device according to any one of claims 1 to 3.

13. A driving control method in which a driving control device mounted on a work vehicle sequentially sets a plurality of training points acquired by the training run of the work vehicle as target points for the learning run of the work vehicle, and controls the work vehicle to perform a learning run toward the sequentially set target points, The above-mentioned driving control device's teacher driving information acquisition unit acquires the position information of the plurality of teacher points recorded during the teacher driving and the direction of travel of the work vehicle at the plurality of teacher points (hereinafter referred to as the teacher point direction of travel Φt), The current driving information acquisition unit of the above-mentioned driving control device acquires the current position of the work vehicle during the above-mentioned training drive and the direction of travel of the work vehicle at the current position (hereinafter referred to as the current direction of travel Φc), The target point setting unit of the above-mentioned travel control device sequentially sets the multiple teaching points as the target points in accordance with the progress of the work vehicle, The calculation angle calculation unit of the above-mentioned travel control device calculates a first calculation angle θd for correcting the current direction of travel Φc of the work vehicle to a direction from the current position toward the current target point, and a second calculation angle θt for correcting the current direction of travel Φc of the work vehicle to the direction of travel Φt of the teacher point which is the current target point. The control steering angle calculation unit of the above-mentioned travel control device calculates the control steering angle θf of the current position of the work vehicle based on a predetermined function in which the first calculation angle θd and the second calculation angle θt calculated by the calculation angle calculation unit are explanatory variables. The steering control unit of the above-mentioned travel control device has the step of controlling the steering of the work vehicle according to the control steering angle θf calculated by the control steering angle calculation unit. A driving control method characterized by the following:

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