Vehicle transverse movement control method, storage medium and vehicle

Abstract

The invention relates to a vehicle control technology, in particular to a vehicle transverse movement control method, a storage medium and a vehicle. The control method comprises the steps of target path generation, vehicle state sensing, tire force limit calculation, optimization control quantity solving, control execution and dynamic adjustment and termination judgment. According to the technical scheme, the novel control method integrating path prediction and tire force optimization is provided for solving the problems that an existing transverse movement control system is delayed in response, uneven in adhesive force distribution, unstable in posture and the like, and good stability, adaptability and application prospects are achieved.

Description

TECHNICAL FIELD

[0001] The present application relates to vehicle control technology, in particular to a vehicle lateral movement control method, a storage medium and a vehicle. BACKGROUND

[0002] With the development of automatic driving technology and intelligent chassis system, the demand for flexibility and controllability of vehicles is increasing. Especially in limited spaces such as urban narrow lanes and multi-level garages, the turning or parking operation of traditional vehicles is often limited by the minimum turning radius of the vehicle, and high-efficiency escape or precise parking cannot be achieved. In recent years, some intelligent vehicles equipped with four-wheel independent drive and steering function have gradually possessed the ability of lateral movement. So-called lateral movement refers to the overall lateral displacement of the vehicle without rotation or minimal rotation of the vehicle body. This function has significant value for parking in small spaces, automatic lane changing, automatic parking, etc. In the process of realizing lateral movement, the front wheels and the rear wheels of the vehicle need to apply steering angles in opposite directions, and the front and rear wheels generate traction forces in opposite directions to realize longitudinal force cancellation and lateral force combination. How to coordinate the steering angles, driving forces of the front and rear wheels and keep the vehicle posture stable during movement is the key to lateral movement control.

[0003] CN117799449A discloses a control method for adjusting the steering angles and torques of front and rear wheels based on motion data deviation, mainly using PID control strategy to suppress longitudinal deviation. CN119262063B discloses a slip ratio balancing strategy to reduce the difference in adhesion and yaw by coordinating the slip ratios of the driven and driven wheels. Although the above methods improve the safety of the lateral movement process to some extent, they have the following shortcomings:

[0004] 1) The control logic is mainly passive correction, which depends on vehicle deviation feedback and has a lag in response, and lacks foresight;

[0005] 2) The path tracking strategy is not integrated, which cannot meet the high-level demand for accurate pose control in intelligent parking and other scenarios;

[0006] 3) The tire force limit and dynamic boundary are not fully modeled, and the control performance decreases in extreme conditions;

[0007] 4) The control accuracy is limited by single error source adjustment, and there is a lack of overall optimization of the overall system performance.

[0008] In summary, the existing technology is still difficult to meet the comprehensive control requirements of high precision, strong robustness and low energy consumption for vehicle lateral movement in intelligent driving scenarios.

[0009] Although the existing technology has proposed various lateral movement control strategies based on motion state deviation correction or slip ratio matching, it still faces the following key technical problems in practical application:

[0010] 1) The vehicle has problems with yaw and longitudinal deviation during lateral movement, which can easily lead to deviation from the target path or collision with obstacles;

[0011] 2) Failure to uniformly consider tire stress limits and path tracking errors resulted in problems such as low adhesion utilization efficiency and tire overload;

[0012] 3) Lack of global path planning and forward control capabilities leads to delayed control response and unstable lateral movement;

[0013] 4) It is not sensitive to complex terrain or adhesion conditions and cannot adapt to dynamic factors such as differences in adhesion between the front and rear wheels and changes in pitch angle. Summary of the Invention

[0014] The purpose of this invention is to provide a vehicle lateral movement control method, storage medium, and vehicle that can combine the target path, vehicle state, and tire limits to coordinate the four-wheel control quantities in real time through optimization, thereby achieving smoother, more accurate, and more intelligent lateral movement control and solving the problems existing in the background art.

[0015] To achieve the above objectives, this application employs the following technical solution:

[0016] A method for controlling the lateral movement of a vehicle includes the following steps:

[0017] S1. Upon receiving the lateral movement command, the vehicle controller dynamically generates a lateral movement target path based on the current vehicle posture and the desired displacement target.

[0018] S2. The system collects the vehicle's current status parameters in real time;

[0019] S3. Based on the Magic Formula tire model, and combined with the current wheel normal load and ground friction conditions, calculate the maximum available lateral force and longitudinal force boundary of the four wheels.

[0020] S4. Construct an optimal control quantity with the goal of minimizing path tracking error and the constraint of reasonable tire force distribution;

[0021] S5. Send the optimized control values ​​of four-wheel steering angle and driving force to the motor and actuator;

[0022] S6. Real-time monitoring of path error, tire adhesion utilization rate, and energy consumption level.

[0023] Furthermore, in step S1, the target path is that the vehicle's center of gravity should move a fixed distance in the lateral direction, and the vehicle's yaw angle should be maintained within a threshold range. This path is generated using spline functions or trajectory optimization algorithms based on the vehicle dynamics model and path smoothing constraints.

[0024] Further, in step S2, the system collects the current state parameters of the vehicle in real time, including but not limited to: vehicle speed, yaw rate, side slip angle; current steering angle and driving force of front and rear wheels; ground adhesion coefficient, slope information.

[0025] Further, in step S4, the calculation formula of the optimization target is:

[0026]

[0027] wherein, is the lateral position error, is the yaw angle, is the longitudinal / lateral force of each wheel, are weight coefficients, is the yaw rate.

[0028] Further, in step S5, the front wheel is set as steering angle θ_f and driving force F_f, and drives forward;

[0029] the rear wheel is set as steering angle -θ_f and driving force F_r, and drives backward;

[0030] to ensure that the vehicle moves stably along the planned path, and the yaw angle is always controlled within ±5°.

[0031] Further, in step S6, if it is detected that the lateral displacement reaches the set target or the error is less than the threshold value, the lateral movement control is terminated;

[0032] if abnormal pitch, skid or resistance increase is detected, emergency braking or posture correction is initiated.

[0033] A storage medium, which is a computer readable storage medium, has a computer program stored thereon, and the computer program is executed by a processor to implement the steps of the vehicle lateral movement control method of any one of the above.

[0034] A vehicle includes a storage medium, and the device further includes:

[0035] including front wheels and rear wheels, the front wheels and the rear wheels are connected with independent driving motors and steering actuators;

[0036] a vehicle controller, an inertial navigation system, a wheel speed sensor and an environment perception module;

[0037] The environment perception module, the wheel speed sensor and the inertial navigation system are in electrical signal connection with the vehicle controller, and the vehicle controller is in electrical signal connection with the driving motor and the steering actuator.

[0038] The present application has the following beneficial effects: ​​

[0039] 1. Significantly reduce longitudinal deviation and yaw angle error during vehicle lateral movement:

[0040] The technical solution no longer relies on real-time deviation feedback, but actively predicts the lateral movement path, and solves the tire force allocation and control input based on this target, which avoids path drift and vehicle posture deviation from the source.

[0041] 2. Dynamic optimization and rational use of tire force, improve tire use efficiency and vehicle safety:

[0042] By estimating the available tire adhesion force boundary in real time and incorporating it as a constraint into the optimization control process, it can effectively prevent wheel slip or adhesion overload, and enhance the stability and robustness of the system under complex road conditions (such as wet, slope).

[0043] 3. Adapt to different driving instructions and road conditions, with stronger environmental adaptability:

[0044] According to the dynamic parameters such as target path length, pitch change, road adhesion coefficient, etc., the control strategy can be adjusted in real time to adapt to various working conditions such as urban narrow lanes, multi-level garages, and inclined parking spaces.

[0045] 4. Fusion of feedforward path planning and feedback error suppression, improve control responsiveness and accuracy:

[0046] The path is generated in advance by the planning module, and the controller adjusts it in combination with the feedback error, the feedforward + feedback double-loop control structure significantly improves the response ability of the system to sudden disturbances or tire slip.

[0047] 5. Has engineering landing value:

[0048] This scheme can be embedded in the existing line control chassis platform, and the control output is the wheel angle and motor torque instruction, which is easy to integrate and can be iteratively optimized with the vehicle OTA.

[0049] In summary, the present invention provides a new control method that combines path prediction and tire force optimization to solve the problems of "response lag, uneven adhesion force distribution, and unstable posture" existing in the current lateral movement control system, with good stability, adaptability and application prospects. BRIEF DESCRIPTION OF DRAWINGS

[0050] Figure 1 The vehicle lateral movement basic principle diagram described in the embodiment of the present invention;

[0051] Figure 2 The flowchart of the lateral movement control method described in the embodiment of the present invention;

[0052] Figure 3A schematic diagram for vehicle mass center lateral path prediction;

[0053] Figure 4 A schematic diagram for four-wheel force and tire force limit modeling. DETAILED DESCRIPTION

[0054] The technical solutions of the present application will be described in detail below with reference to the accompanying drawings, and the following examples are only exemplary and can only be used to explain and illustrate the technical solutions of the present application, but cannot be interpreted as a limitation of the technical solutions of the present application.

[0055] The present application provides a vehicle lateral movement control method based on path prediction and tire force distribution, which can combine target path, vehicle state and tire limit, and realize more stable, more accurate and more intelligent lateral movement control by optimizing four-wheel control amount in real time.

[0056] The technical solutions are applicable to vehicles with four-wheel independent driving and independent steering capability, including electric or hybrid platforms that can control the driving force and steering angle of the front and rear wheels respectively.

[0057] As shown in Figure 1 The vehicle related to the present application comprises:

[0058] Two front wheels and two rear wheels;

[0059] The front and rear wheels are connected with independent driving motors and steering actuators;

[0060] Equipped with a vehicle controller (VCU), an inertial navigation system (IMU), a wheel speed sensor and an environment perception module.

[0061] As shown in Figures 2 to 4 The present application provides a vehicle lateral movement control method, comprising the following steps:

[0062] S1, target path generation:

[0063] After receiving the lateral movement instruction, the vehicle controller first generates a lateral movement target path based on the current vehicle attitude (yaw angle, vehicle orientation, position) and the expected displacement target.

[0064] The target path is that the vehicle mass center should move a fixed distance in the lateral direction (X axis), and the vehicle yaw angle is maintained within a threshold range (such as ±5°); it can be generated based on the vehicle dynamics model and path smoothing constraints using spline function or trajectory optimization algorithm.

[0065] The present application introduces a path prediction model in lateral movement control, dynamically generates a vehicle lateral target trajectory, and inputs it into the optimizer as a control target, instead of relying only on position error feedback.

[0066] S2, Vehicle state perception:

[0067] The system collects the current state parameters of the vehicle in real time, including but not limited to: vehicle speed, yaw rate, side slip angle; current steering angle and driving force of front and rear wheels; ground adhesion coefficient, slope information (estimated by map or sensor).

[0068] S3, Tire force limit calculation:

[0069] Based on the Magic Formula tire model, combined with the current wheel normal load and ground friction conditions, the maximum available lateral force and longitudinal force boundary of the four wheels is calculated to ensure that the subsequent control does not exceed the force limit.

[0070] Real-time calculation of tire force limit of four wheels (considering friction coefficient and vertical load), and introduce this boundary as a constraint in control to ensure tire usage rationality and vehicle stability.

[0071] S4, Optimization control quantity solving:

[0072] Construct an optimization problem with the goal of minimizing path tracking error and the constraint of reasonable tire force distribution:

[0073] State variables include vehicle mass center position, attitude angle, tire lateral force, etc.

[0074] Control variables are the steering angle and driving force of each wheel;

[0075] Optimization goals can be:

[0076] ,

[0077] Where, is the lateral position error, is the yaw angle, is the longitudinal / lateral force of each wheel, - are weight coefficients, is the yaw rate.

[0078] Use model predictive control (MPC) or quadratic programming (QP) to solve the optimal control sequence. Construct a unified objective function, use lateral error, yaw angle, lateral force usage rate, etc. as cost items, solve control variables through prediction and rolling optimization to improve tracking accuracy and robustness.

[0079] S5, Control execution:

[0080] The four-wheel steering angle and driving force control variables obtained by solving are sent to the motor and actuator:

[0081] The front wheels are set to steering angle θ_f and driving force F_f, driving forward;

[0082] The rear wheel is set to a rotation angle -θ_f, a driving force F_r, and is driven rearward;

[0083] Ensure that the vehicle moves stably along the planned path, and the yaw angle is always controlled within ±5°.

[0084] S6, dynamically adjust and terminate the judgment:

[0085] Real-time monitoring of path error, tire adhesion utilization rate and energy consumption level;

[0086] If the lateral displacement reaches the set target or the error is less than the threshold value, terminate the lateral displacement control;

[0087] If abnormal pitch, skid or resistance increases are detected, initiate emergency braking or posture correction.

[0088] The present application can switch the control target and control constraint parameters according to the current speed of the vehicle, the road adhesion, the pitch slope and other information, thereby improving the environmental adaptability and scene versatility of the system.

[0089] The present application provides a storage medium, which is a computer readable storage medium, and a computer program is stored on the storage medium, and the computer program is executed by a processor to implement the steps of the vehicle lateral movement control method of any one of the above.

[0090] The computer readable storage medium provided by the present application may, for example, be a U disk, but is not limited to an electrical, magnetic, optical, electromagnetic, infrared, or semiconductor system, system or device, or any combination of the above. More specific examples of computer readable storage media can include, but are not limited to, an electrical connection with one or more conductive wires, a portable computer disk, a hard disk, a random access memory (RAM: Random Access Memory), a read-only memory (ROM: Read Only Memory), an erasable programmable read-only memory (EPROM: Erasable Programmable Read Only Memory or flash memory), an optical fiber, a portable compact disk read-only memory (CD-ROM: CD-Read Only Memory), an optical storage device, a magnetic storage device, or any suitable combination of the above. In the present embodiment, the computer readable storage medium can be any tangible medium containing or storing a program that can be used by or in conjunction with an instruction execution system, system or device. The program code contained on the computer readable storage medium can be transmitted by any appropriate medium, including but not limited to: electrical wires, optical cables, RF (Radio Frequency: Radio Frequency), etc., or any suitable combination of the above.

[0091] The application provides a vehicle, comprising the storage medium, and the device further comprises:

[0092] The vehicle comprises front wheels and rear wheels, and the front wheels and the rear wheels are connected with independent driving motors and steering actuators;

[0093] The vehicle controller, the inertial navigation system, the wheel speed sensor and the environment perception module;

[0094] The environment perception module, the wheel speed sensor and the inertial navigation system are electrically connected with the vehicle controller, and the vehicle controller is electrically connected with the driving motor and the steering actuator.

[0095] Although the embodiments of the application have been shown and described, it is to be understood that the application is not limited to these embodiments. It will be obvious to a person skilled in the art that various changes, modifications, replacements and variations can be made to the embodiments without departing from the principles and spirit of the application, and the scope of the application is defined by the appended claims and their equivalents.

Claims

1. A vehicle lateral movement control method characterized by, Includes the following steps: S1. Upon receiving the lateral movement command, the vehicle controller dynamically generates a lateral movement target path based on the current vehicle posture and the desired displacement target. S2. The system collects the vehicle's current status parameters in real time; S3. Based on the Magic Formula tire model, and combined with the current wheel normal load and ground friction conditions, calculate the maximum available lateral force and longitudinal force boundary of the four wheels. S4. Construct an optimal control quantity with the goal of minimizing path tracking error and the constraint of reasonable tire force distribution; S5. Send the optimized control values ​​of four-wheel steering angle and driving force to the motor and actuator; S6. Real-time monitoring of path error, tire adhesion utilization rate, and energy consumption level.

2. The vehicle lateral movement control method according to claim 1, characterized by, In step S1, the target path is that the vehicle's center of gravity should move a fixed distance in the lateral direction, and the vehicle's yaw angle should be maintained within a threshold range. This path is generated using spline functions or trajectory optimization algorithms based on the vehicle dynamics model and path smoothing constraints.

3. The vehicle lateral movement control method according to claim 1, characterized in that, In step S2, the system collects the vehicle's current status parameters in real time, including but not limited to: vehicle speed, yaw rate, sideslip angle; current steering angle and driving force of the front and rear wheels; ground adhesion coefficient and slope information.

4. The vehicle lateral movement control method according to claim 1, characterized in that, In step S4, the formula for calculating the optimization objective is: ， in, This is the lateral position error. For the horizontal swing angle, For the longitudinal / lateral forces of each wheel, - All are weighting coefficients. ω represents the yaw rate.

5. The vehicle lateral movement control method according to claim 1, characterized in that, In step S5, the front wheel is set to a steering angle θ_f and a driving force F_f to drive forward; The rear wheel is set to a steering angle of -θ_f and a driving force of F_r, driving backward. Ensure that the vehicle moves stably laterally along the planned path, with the yaw angle always controlled within ±5°.

6. The vehicle lateral movement control method according to claim 1, characterized in that, In step S6, if the detected lateral displacement reaches the set target or the error is less than the threshold, the lateral movement control is terminated. If abnormal pitch, slippage, or a sudden increase in drag is detected, emergency braking or attitude correction will be initiated.

7. A storage medium, characterized in that, The storage medium is a computer-readable storage medium, and a computer program is stored on the storage medium. When the computer program is executed by a processor, it implements the steps of the vehicle lateral movement control method according to any one of claims 1 to 6.

8. A vehicle, characterized in that, The device, comprising the storage medium of claim 7, further includes: It includes front wheels and rear wheels, each of which is connected to an independent drive motor and a steering actuator; Vehicle controller, inertial navigation system, wheel speed sensor and environmental perception module; The environmental perception module, wheel speed sensor, and inertial navigation system are all electrically connected to the vehicle controller, which in turn is electrically connected to the drive motor and steering actuator.

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