Control system and control method

Abstract

To improve vehicle's ability to follow a target route.SOLUTION: A control system S comprises: a first acquisition section 121 to acquire a distance deviation of a vehicle from a route point along a target route of the vehicle, an azimuth angle deviation between the first azimuth angle of the route point and the second azimuth angle of the vehicle, and the steering angle of the vehicle; a generation section 122 to generate prediction models for the distance deviation, the azimuth angle deviation, and the steering angle; a second acquisition section 124 to acquire a curvature degree of a road on which the vehicle is traveling; a calculation section 125 to calculate the sideslip angle of the vehicle on the basis of the degree of curvature; an estimation section 123 to estimate an estimated distance deviation, the steering angle, and an estimated azimuth angle deviation on the basis of the prediction models; and a determination section 126 to determine the steering angle, as a target steering angle, which minimizes an evaluation function including, as parameters, a difference between the estimated azimuth angle deviation and the sideslip angle, the estimated distance deviation and the steering angle.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a control system and a control method for controlling the behavior of a vehicle.

Background Art

[0002] A control system for controlling the behavior of a vehicle is known. Patent Document 1 discloses a technique for determining a steering angle that minimizes the value of an evaluation function including a lateral deviation, an azimuth angle deviation, a steering angle, and a change amount of the steering angle.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] By the way, when a vehicle turns, it turns by generating a side slip angle between the traveling direction of the vehicle and the direction of the wheels. Therefore, when the vehicle is traveling along a target path with a large curvature, it is necessary to set the steering angle, which is the direction of the wheels of the vehicle, to an angle at which a side slip angle is generated such that the vehicle follows the target path. However, the side slip angle generated by the steering angle of the vehicle determined without considering the side slip angle may be different from the side slip angle for turning the vehicle along the target path. Therefore, with a steering angle that does not take into account the side slip angle, the vehicle turns so as to deviate from the target path, and the vehicle cannot follow the target path.

[0005] Therefore, the present invention has been made in view of these points, and an object thereof is to improve the followability of the vehicle to the target path.

Means for Solving the Problems

[0006] In a first aspect of the present invention, there is provided a control system including: a first acquisition unit that acquires a distance deviation between a route point of a target route of a vehicle and the vehicle, an azimuth deviation between a first azimuth angle of the route point and a second azimuth angle of the vehicle, and a steering angle of the vehicle; a generation unit that generates a prediction model for predicting each of the distance deviation, the azimuth deviation, and the steering angle; a second acquisition unit that acquires a degree of curvature of a road on which the vehicle is traveling; a calculation unit that calculates a sideslip angle of the vehicle based on the degree of curvature; an estimation unit that estimates an estimated distance deviation, a steering angle, and an estimated azimuth deviation based on the prediction model; and a determination unit that determines the steering angle that minimizes an evaluation function including a difference between the estimated azimuth deviation and the sideslip angle, the estimated distance deviation, and the steering angle as parameters as a target steering angle. The calculation unit may calculate the sideslip angle based on a balance of forces in the vehicle width direction orthogonal to the traveling direction of the vehicle determined according to the degree of curvature and a balance of forces in the rotational direction around the center of gravity of the vehicle.

[0007] The balance of forces in the vehicle width direction is represented by a centrifugal force determined by the weight of the vehicle, the vehicle speed of the vehicle, and the degree of curvature, and a centripetal force determined by the front wheel cornering stiffness of the vehicle, the sideslip angle of the front wheels of the vehicle, the rear wheel cornering stiffness of the vehicle, and the sideslip angle of the rear wheels of the vehicle. The balance of forces in the rotational direction is represented by a yaw moment of the front wheels determined by a first distance between the center of gravity of the vehicle and the front wheels, the front wheel cornering stiffness, and the sideslip angle of the front wheels, and a yaw moment of the rear wheels determined by a second distance between the center of gravity and the rear wheels, the rear wheel cornering stiffness, and the sideslip angle of the rear wheels.

[0008] The centrifugal force is represented by the product of the weight and the ratio of the square of the vehicle speed to the radius of curvature indicating the degree of bending, and the centripetal force is represented by the sum of the product of the front-wheel cornering stiffness and the sideslip angle of the front wheels and the product of the rear-wheel cornering stiffness and the sideslip angle of the rear wheels. The balance of the forces in the rotational direction may be represented by the first product of the first distance, the front-wheel cornering stiffness, and the sideslip angle of the front wheels and the second product of the second distance, the rear-wheel cornering stiffness, and the sideslip angle of the rear wheels.

[0009] The calculation unit may calculate the sideslip angle of the rear wheels, which is derived by eliminating the sideslip angle of the front wheels, from the expression representing the balance of the forces in the vehicle width direction represented by the centrifugal force and the centripetal force and the expression representing the balance of the forces in the rotational direction represented by the first product and the second product, as the sideslip angle.

[0010] In a second aspect of the present invention, there is provided a control method including steps of: acquiring a distance deviation between a path point of a target path of a vehicle and the vehicle, an azimuth angle deviation between a first azimuth angle of the path point and a second azimuth angle of the vehicle, and a steering angle of the vehicle, which are executed by a processor mounted on the vehicle; generating a prediction model for predicting each of the distance deviation, the azimuth angle deviation, and the steering angle; acquiring a degree of bending of a road on which the vehicle is traveling; calculating a sideslip angle of the vehicle based on the degree of bending; estimating an estimated distance deviation, a steering angle, and an estimated azimuth angle deviation based on the prediction model; and determining, as a target steering angle, the steering angle that minimizes an evaluation function including, as parameters, a difference between the estimated azimuth angle deviation and the sideslip angle, the estimated distance deviation, and the steering angle.

Advantages of the Invention

[0011] According to the present invention, there is an effect that the followability of the vehicle to the target path is improved.

Brief Description of the Drawings

[0012]

Figure 1

Figure 2

Figure 3

Embodiments for Carrying Out the Invention

[0013] [Configuration of Control System S] The configuration of the control system S will be described with reference to FIGS. 1 and 2. FIG. 1 is a diagram for explaining the movement of the vehicle A. FIG. 2 is a diagram for explaining the configuration of the control system S. The control system S is a system for causing the vehicle A to travel along the target route B by controlling the steering angle δ of the vehicle A. The control system S includes a vehicle control device 1 and is mounted on the vehicle A. The target route B is a predetermined route and includes route points indicating a plurality of running positions that the vehicle A aims for and the direction that the vehicle A aims for at each route point.

[0014] In FIG. 1, an absolute coordinate system is used. The absolute coordinate system of the present embodiment uses, for example, the longitude direction as the X-axis and the latitude direction as the Y-axis, but is not limited thereto. Hereinafter, the speed component in the vehicle width direction of the vehicle speed V of the vehicle A is the vehicle width direction speed Vy. The speed component in the traveling direction orthogonal to the vehicle width direction of the vehicle speed V is the longitudinal direction speed Vx.

[0015] The distance deviation z is the distance between the center of gravity point C indicating the position of the vehicle A and the route point D of the target route B of the vehicle A. The azimuth deviation θ is the difference between the first azimuth ψ indicating the direction of the route point D of the target route B and the second azimuth φ indicating the direction of the vehicle A. The first azimuth ψ is the direction that the vehicle A aims for. The first azimuth ψ is, for example, the direction of the tangent line of the route point D.

[0016] The vehicle control device 1 is, for example, an ECU (Electronic Control Unit). The vehicle control device 1 includes a storage unit 11 and a control unit 12. The storage unit 11 is a storage medium including a ROM (Read Only Memory), a RAM (Random Access Memory), a hard disk, and the like. The storage unit 11 stores a program executed by the control unit 12.

[0017] The control unit 12 is a computing resource including a processor such as a CPU (Central Processing Unit), for example. By executing the program stored in the storage unit 11, the control unit 12 realizes functions as a first acquisition unit 121, a generation unit 122, an estimation unit 123, a second acquisition unit 124, a calculation unit 125, a determination unit 126, and a steering control unit 127.

[0018] The first acquisition unit 121 acquires a plurality of pieces of information regarding the vehicle A. For example, the first acquisition unit 121 uses the coordinates indicating the position of the vehicle A specified by a positioning system that measures the position using a signal output from a satellite and the coordinates indicating the position of the path point D of the target path to acquire a distance deviation z. The first acquisition unit 121 acquires a first azimuth angle ψ and a second azimuth angle φ, and acquires the difference between the first azimuth angle ψ and the second azimuth angle φ as an azimuth angle deviation θ. The first acquisition unit 121 acquires the steering angle δ of the vehicle A. For example, the first acquisition unit 121 acquires the steering angle δ detected by the steering angle sensor 3 from the steering angle sensor 3 that detects the steering angle δ.

[0019] The generation unit 122 generates a prediction model for predicting the state of the vehicle A. For example, the generation unit 122 generates a prediction model for predicting each of the distance deviation z, the azimuth angle deviation θ, and the steering angle δ. Specifically, the generation unit 122 generates, as a prediction model, a state equation represented by the following equation (1) and having the distance deviation z, the azimuth angle deviation θ, and the steering angle δ as state variables. Note that the state equation of equation (1) is a discretized state equation.

Equation

[0020] The second acquisition unit 124 acquires the degree of curvature of the road on which the vehicle A is traveling. The degree of curvature of the road is the radius of curvature R or the curvature which is the reciprocal of the radius of curvature R. For example, the second acquisition unit 124 acquires the radius of curvature R indicating the degree of curvature of the road. Specifically, the second acquisition unit 124 acquires the radius of curvature R of the road by analyzing the captured image captured by the imaging device mounted on the vehicle A. Further, the second acquisition unit 124 may acquire the radius of curvature R of the road on which the vehicle A is traveling by referring to the map information associating the position of the road with the radius of curvature R of the road. The map information is stored in the storage unit 11. Note that the second acquisition unit 124 may acquire the curvature indicating the degree of curvature of the road instead of the radius of curvature R.

[0021] The calculation unit 125 calculates the sideslip angle β of the vehicle A based on the radius of curvature R acquired by the second acquisition unit 124. For example, the calculation unit 125 calculates the sideslip angle β based on the balance of the forces in the vehicle width direction orthogonal to the traveling direction of the vehicle A determined according to the radius of curvature R and the balance of the forces in the rotational direction around the center of gravity of the vehicle A.

[0022] The balance of the forces in the vehicle width direction is represented by the centrifugal force and the centripetal force acting on the vehicle A. The centrifugal force is determined by the weight m of the vehicle, the vehicle speed V of the vehicle A, and the radius of curvature R. Specifically, the centrifugal force is represented by the product of the ratio of the square of the vehicle speed V to the radius of curvature R and the weight m. The centripetal force is determined by the front wheel cornering stiffness K f , the sideslip angle β of the front wheel f , the rear wheel cornering stiffness K r and the sideslip angle β of the rear wheel r . Specifically, the centripetal force is represented by the sum of the product of the front wheel cornering stiffness K f and the sideslip angle β of the front wheel f and the product of the rear wheel cornering stiffness K r and the sideslip angle β of the rear wheel r . The balance of the forces in the vehicle width direction is represented by the following formula (2).

Equation

[0023] The balance of the forces in the rotational direction around the center of gravity of vehicle A is represented by the balance between the force that causes vehicle A to turn clockwise and the force that causes vehicle A to turn counterclockwise with respect to the vertical axis passing through the center of gravity of vehicle A. Specifically, the balance of the forces in the rotational direction is represented by the yaw moment of the front wheels and the yaw moment of the rear wheels.

[0024] The yaw moment of the front wheels is determined by the first distance l between the center of gravity of vehicle A and the axle of the front wheels f , the front wheel cornering stiffness K f and the slip angle β of the front wheels. f Specifically, the yaw moment of the front wheels is the first product of the first distance l f , the front wheel cornering stiffness K f and the slip angle β of the front wheels. f The yaw moment of the rear wheels is determined by the second distance l between the center of gravity and the axle of the rear wheels r , the rear wheel cornering stiffness K r and the slip angle β of the rear wheels. r Specifically, the yaw moment of the rear wheels is the second product of the second distance l between the center of gravity and the rear wheels r , the rear wheel cornering stiffness K r and the slip angle β of the rear wheels. r The balance of the forces in the rotational direction is represented by the following formula (3).

Equation

[0025] The calculation unit 125 calculates the slip angle β of the rear wheels f derived by eliminating the slip angle β of the front wheels from the formula (2) representing the balance of the forces in the vehicle width direction and the formula (3) representing the balance of the forces in the rotational direction. The calculation unit 125 calculates the slip angle β of the rear wheels r as the steady-state slip angle θ. r The calculation unit 125 calculates the steady-state slip angle θ ref using the following formula (4). The calculation unit 125 calculates the slip angle β of the rear wheels ref as the steady-state slip angle θ. r The slip angle β of the rear wheels refThe state equation in the case of using the sideslip angle of the center of gravity becomes a simpler equation than the state equation in the case of using the sideslip angle of the center of gravity.

Number

[0026] The determination unit 126 determines the target steering angle of the vehicle A. The determination unit 126 determines the steering angle that minimizes the evaluation function J as the target steering angle. The evaluation function J includes the estimated azimuth deviation, the difference from the steady-state sideslip angle θ ref as parameters, the estimated distance deviation, and the steering angle. The evaluation function J is expressed by the following equation (5) using the weight Q y of the lateral deviation, the weight Q θ of the azimuth deviation, the weight R δ of the target steering angle, the terminal weight Q δterm of the lateral deviation, and the terminal weight Q θterm of the azimuth deviation.

Number

[0027] As shown in the above equation (5), the steering angle δ that minimizes the evaluation function J is a steering angle that reduces the difference between the azimuth deviation θ and the steady-state sideslip angle θ ref . In other words, the determination unit 126 can determine the steering angle δ that makes the direction of the vehicle A coincide with the steady-state sideslip angle θ ref . As a result, the direction of the vehicle A becomes an angle that generates a lateral force corresponding to the radius of curvature R of the road on which the vehicle A is traveling. As a result, the vehicle A travels along the target path B.

[0028] The steering control unit 127 operates the steering wheel 2 of the vehicle A to set the steering angle of the vehicle A to the target steering angle. For example, the steering control unit 127 rotates the steering wheel 2 so that the steering angle becomes the target steering angle by controlling an actuator that rotates the steering wheel 2.

[0029] After the steering control unit 127 sets the steering angle to the target steering angle, the first acquisition unit 121 acquires the distance deviation z, the azimuth angle deviation θ, and the steering angle δ again, and the second acquisition unit 124 acquires the radius of curvature R of the road on which the vehicle A travels again. The determination unit 126 determines the target steering angle based on the acquired information about the vehicle A, and the steering control unit 127 rotates the steering wheel 2 of the vehicle A so as to achieve the determined target steering angle.

[0030] In this way, the vehicle control device 1 mounted on the vehicle A determines the target steering angle based on the acquired information about the vehicle A, and rotates the steering wheel 2 of the vehicle A so as to achieve the determined target steering angle. While the vehicle A is traveling, the vehicle control device 1 repeatedly executes the process of acquiring information about the vehicle A and the process of rotating the steering wheel 2, thereby enabling the vehicle A to travel along the target route B.

[0031] The steering angle δ determined by the vehicle control device 1 is the steering angle that minimizes the evaluation function J including as a parameter the difference between the estimated azimuth angle deviation θ of the vehicle A and the steady-state sideslip angle θ ref corresponding to the radius of curvature R of the road on which the vehicle A travels. When the difference between the estimated azimuth angle deviation θ and the steady-state sideslip angle θ ref becomes small, the steering angle δ of the vehicle A comes to coincide with the steady-state sideslip angle θ ref that generates a lateral force corresponding to the radius of curvature R. That is, the steering angle δ of the vehicle A comes to coincide with an appropriate sideslip angle that enables the vehicle A to travel along the target route B having a large curvature. As a result, the vehicle control device 1 can reduce the distance deviation z between the path point D of the target route B and the vehicle A, and thus can improve the followability of the vehicle A to the target route B having a large curvature.

[0032] Incidentally, a straight road may be regarded as having an infinite radius of curvature R. The second acquisition unit 124 acquires infinity as the radius of curvature R, but it may be not only infinity but also a sufficiently large value. The sufficiently large value is, for example, 10,000 times the radius of curvature R of an actual road, but is not limited thereto. In this case, the calculation unit 125 calculates 0 as the steady-state sideslip angle θ ref The steady-state sideslip angle θ refWhen the evaluation function J is minimized when it is 0, the steering angle δ is a steering angle that reduces the difference between the second azimuth angle φ of the vehicle A and the first azimuth angle ψ of the path point D of the target path B, and is a steering angle that aligns the direction of the wheels of the vehicle A with the traveling direction.

[0033] Thus, the vehicle control device 1 can use the same evaluation function J whether the road on which the vehicle A is traveling is straight or curved. As a result, the vehicle control device 1 does not need to change the processing depending on whether the road on which the vehicle A is traveling is straight or curved. Therefore, the vehicle control device 1 can make the vehicle A travel with the same processing even when the target path B has a mixture of straight lines and curves.

[0034] [Process for controlling travel] FIG. 3 is a flowchart showing an example of a process for controlling the travel of the vehicle A. The process for controlling the travel of the vehicle A is executed while the vehicle A is traveling.

[0035] The first acquisition unit 121 acquires the distance deviation z, the azimuth angle deviation θ, and the steering angle δ (step S1). Specifically, the first acquisition unit 121 acquires the distance deviation z using the coordinates indicating the position of the vehicle A specified by the positioning system and the coordinates indicating the position of the path point D of the target path. The first acquisition unit 121 acquires the first azimuth angle ψ indicating the slope of the tangent line of the path point D and the second azimuth angle φ indicating the direction of the vehicle A, and acquires the difference between the first azimuth angle ψ and the second azimuth angle φ as the azimuth angle deviation θ. The first acquisition unit 121 acquires the steering angle δ detected by the steering angle sensor 3.

[0036] The generation unit 122 generates a prediction model for predicting each of the distance deviation z, the azimuth angle deviation θ, and the steering angle δ (step S2). Specifically, the generation unit 122 generates the state equation represented by Equation (1) as the prediction model. The estimation unit 123 estimates the estimated distance deviation, the estimated azimuth angle deviation, and the steering angle based on the prediction model represented by Equation (1) (step S3).

[0037] The second acquisition unit 124 acquires the radius of curvature R as the degree of curvature of the road on which the vehicle A is traveling (step S4). The calculation unit 125 calculates the sideslip angle β of the vehicle according to the acquired radius of curvature R (step S5). Specifically, the calculation unit 125 calculates the sideslip angle β based on the balance of the forces in the vehicle width direction acting on the vehicle A and the balance of the forces in the rotational direction. Note that the processes of step S4 and step S5 may be executed before the processes of step S1 to step S3, or may be executed in parallel with the processes of step S1 to step S3.

[0038] The determination unit 126 determines the steering angle that minimizes the evaluation function J including the difference between the estimated azimuth angle deviation and the sideslip angle as the target steering angle (step S6). Specifically, the determination unit 126 determines the steering angle that minimizes the evaluation function J including the difference between the estimated azimuth angle deviation and the sideslip angle, the estimated distance deviation, and the steering angle as the target steering angle.

[0039] The first acquisition unit 121 determines whether the vehicle A has stopped (step S7). When the vehicle A has stopped (Yes in step S7), the first acquisition unit 121 ends the process of controlling the travel of the vehicle A. When the vehicle A is traveling (No in step S7), the first acquisition unit 121 returns to step S1 and acquires the distance deviation z, the azimuth angle deviation θ, and the steering angle δ. Note that when the stopped vehicle A starts traveling, the first acquisition unit 121 starts the process of controlling the travel of the vehicle A.

[0040] [Effect of the control system S] As described above, the control system S acquires the distance deviation between the path point of the target path of the vehicle and the vehicle A, the azimuth angle deviation between the first azimuth angle of the path point and the second azimuth angle of the vehicle A, the steering angle, and the degree of curvature of the road on which the vehicle A travels. Next, the control system S estimates the estimated distance deviation, the steering angle, and the estimated azimuth angle deviation based on a prediction model that predicts each of the distance deviation, the azimuth angle deviation, and the steering angle. Subsequently, the control system S calculates the sideslip angle of the vehicle A based on the degree of curvature. Then, the control system S determines the steering angle that minimizes the evaluation function including the difference between the estimated azimuth angle deviation and the sideslip angle, the estimated distance deviation, and the steering angle as the target steering angle.

[0041] The steering angle δ determined by the control system S is the steering angle that minimizes the evaluation function J including, as parameters, the difference between the estimated azimuth angle deviation θ of the vehicle A and the sideslip angle based on the degree of curvature of the road on which the vehicle A travels. The steering angle that minimizes the evaluation function J is the steering angle that reduces the difference between the estimated azimuth angle deviation and the sideslip angle. When the difference between the estimated azimuth angle deviation and the sideslip angle becomes small, the steering angle of the vehicle A comes to coincide with the sideslip angle that generates a lateral force corresponding to the degree of curvature of the road. That is, the steering angle of the vehicle A comes to coincide with an appropriate sideslip angle that enables traveling along the target path B with a large curvature. Thereby, the control system S can reduce the distance deviation between the path point D of the target path B and the vehicle A, and thus can improve the followability of the vehicle A to the target path B.

[0042] As described above, the present invention has been described using the embodiments, but the technical scope of the present invention is not limited to the scope described in the above embodiments, and various modifications and changes are possible within the scope of the gist. For example, all or part of the device can be configured by being functionally or physically dispersed and integrated in an arbitrary unit. Also, new embodiments generated by any combination of a plurality of embodiments are included in the embodiments of the present invention. The effects of the new embodiments generated by the combination have the effects of the original embodiments combined.

Explanation of Reference Numerals

[0043] 1 Vehicle control device 2 Steering wheel 3 Steering angle sensor 11 Storage unit 12 Control unit 121 First acquisition unit 122 Generation unit 123 Estimation unit 124 Second acquisition unit 125 Calculation unit 126 Determination unit 127 Steering control unit A Vehicle

Claims

1. A first acquisition unit that acquires a distance deviation between a path point on a target path of a vehicle and the vehicle, an azimuth deviation between a first azimuth angle of the path point and a second azimuth angle of the vehicle, and a steering angle of the vehicle; A generation unit that generates a prediction model for predicting each of the distance deviation, the azimuth deviation, and the steering angle; A second acquisition unit that acquires a degree of curvature of a road on which the vehicle is traveling; A calculation unit that calculates a sideslip angle of the vehicle based on the degree of curvature; An estimation unit that estimates an estimated distance deviation, a steering angle, and an estimated azimuth deviation based on the prediction model; A determination unit that determines the steering angle that minimizes an evaluation function including a difference between the estimated azimuth deviation and the sideslip angle, the estimated distance deviation, and the steering angle as parameters as a target steering angle; A control system having the above.

2. The calculation unit calculates the sideslip angle based on a balance of forces in the vehicle width direction orthogonal to the traveling direction of the vehicle determined according to the degree of curvature and a balance of forces in the rotational direction around the center of gravity of the vehicle. The control system according to claim 1.

3. The balance of forces in the vehicle width direction is The centrifugal force determined by the weight of the vehicle, the vehicle speed of the vehicle, and the degree of curvature, The centripetal force determined by the front wheel cornering stiffness of the vehicle, the sideslip angle of the front wheels of the vehicle, the rear wheel cornering stiffness of the vehicle, and the sideslip angle of the rear wheels of the vehicle, Represented by The balance of forces in the rotational direction is The yaw moment of the front wheels determined by a first distance between the center of gravity of the vehicle and the front wheels, the front wheel cornering stiffness, and the sideslip angle of the front wheels, Represented by the yaw moment of the rear wheels determined by a second distance between the center of gravity and the rear wheels, the rear wheel cornering stiffness, and the sideslip angle of the rear wheels. The control system according to claim 2.

4. The centrifugal force is represented by the product of the ratio of the square of the vehicle speed to the radius of curvature indicating the degree of curvature and the weight, The centripetal force is represented by the sum of the product of the front wheel cornering stiffness and the sideslip angle of the front wheels and the product of the rear wheel cornering stiffness and the sideslip angle of the rear wheels, The balance of forces in the rotational direction is represented by a first product of the first distance, the front wheel cornering stiffness, and the sideslip angle of the front wheels and a second product of the second distance, the rear wheel cornering stiffness, and the sideslip angle of the rear wheels. The control system according to claim 3.

5. The calculation unit calculates the lateral slip angle of the rear wheels derived by eliminating the front wheel lateral slip angle from an expression representing the balance of the forces in the vehicle width direction represented by the centrifugal force and the centripetal force, and an expression representing the balance of the forces in the rotational direction represented by the first product and the second product, as the lateral slip angle. The control system according to claim 4.

6. Executed by a processor mounted on a vehicle Obtaining a distance deviation between a path point of a target path of the vehicle and the vehicle, an azimuth deviation between a first azimuth angle of the path point and a second azimuth angle of the vehicle, and a steering angle of the vehicle; Generating a prediction model for predicting each of the distance deviation, the azimuth deviation, and the steering angle; Obtaining a degree of curvature of a road on which the vehicle is traveling; Calculating a lateral slip angle of the vehicle based on the degree of curvature; Estimating an estimated distance deviation, a steering angle, and an estimated azimuth deviation based on the prediction model; Determining a target steering angle as a steering angle that minimizes an evaluation function including as parameters a difference between the estimated azimuth deviation and the lateral slip angle, the estimated distance deviation, and the steering angle; A control method having the above.

Images