Upper-layer motion state control method for four-hub motor-driven vehicle

Abstract

The invention discloses an upper-layer motion state control method for a four-hub motor driven vehicle, realizes dynamic adjustment of a vehicle motion state reference value based on fuzzy control, obtains a comprehensive reference quantity by correcting a yaw velocity reference value, can effectively simplify the design of centroid slip angle and yaw velocity self-adaptive joint control, and themaneuverability and the stability of the vehicle under different attachment conditions can be comprehensively coordinated. The upper-layer motion controller based on the improved sliding mode controlmethod established in the method can effectively realize the combined control of motion state quantities such as longitudinal vehicle speed, yaw velocity and side slip angle, and is relatively small in buffeting and relatively high in response speed while ensuring the control precision. The adaptive capacity of motion control to external disturbance and system parameter change is improved to a certain extent, and a good tracking effect of the vehicle on each reference motion state is ensured. Therefore, the final torque distribution provided by the invention can ensure good operation stabilityof the vehicle under different attachment conditions.

Description

technical field [0001] The invention relates to the technical field of distributed drive vehicle control, in particular to a control method for realizing stable maneuvering of a four-wheel-hub motor-driven vehicle under road conditions with different adhesion coefficients and variable adhesion coefficients. Background technique [0002] The driving / braking torque of the four driving wheels of the four-wheel hub motor drive vehicle can be independently controlled, which is more conducive to the realization of steering stability control during the steering process. At present, the direct yaw moment control (DYC) is mostly used for the steering stability control of in-wheel motor driven vehicles, which can achieve good stability control effects in both linear and nonlinear working areas of tires. DYC-based handling and stability control strategies mainly have two control structures: integrated control and hierarchical control. Among them, hierarchical control mainly includes u...

AI Technical Summary

Problems solved by technology

[0003] 1. Most of the upper-level motion control only reflects the control of the vehicle yaw rate, without considering the influence of the side slip angle of the center of mass on the handling stability, and lacks the joint control of the side slip angle of the center of mass and the yaw rate;

[0004] 2. Most of the upper-level motion controls do not set reference values ​​for the yaw rate and the side slip angle of the center of mass and control them. They only constrain the dynamic parameters and fail to achieve accurate control of the yaw rate and the side slip angle of the center of mass;

[0005] 3. Most of the upper-level motion controls have too high requirements for the estimation of the center of mass side slip angle and the accuracy of the tire model, the weight coefficient is difficult to determine, lacks physical meaning, and is not convenient for system tuning;

[0006] 4. At present, little consideration has been given to the influence of road surface adhesion coefficient on the motion control of the upper layer. Under different adhesion coefficients, the response of the side slip angle and yaw rate of the center of mass has different effects on the control of vehicle handling stability. The existing research on the two It is difficult to realize the adaptive control of road surface adhesion by joint control method

Images