Research On Brake Anti-lock Control For In-wheel Motor Electric Vehicle

Because the wheel hub motor is directly installed inside the wheel,the wheel moment of inertia increases significantly.The increase in the wheel wheel moment of inertia will significantly affect the control effect of the traditio nal anti-lock braking system(ABS)in the wheel hub electric vehicle.Affect the braking safety of the vehicle.Especially during cornering braking,the longitudinal loads of the front and rear axles and the inner and outer wheels change.Under extreme uns table conditions,the wheels can easily reach the limit of the adhesion coefficient,which affects the braking stability of the vehicle.Therefore,under the premise of ensuring the wheels are not locked and the braking efficiency,ABS should also consider the problem of vehicle braking stability under complex working conditions.Based on this,this paper makes the following research on the anti-lock braking control of the wheel motor electric vehicle:(1)Established a vehicle dynamics model for the simulation study of the anti-lock braking control of the wheel motor electric vehicle brake,including a seven-degree-of-freedom vehicle model and a two-degree-of-freedom vehicle reference model.(2)Aiming at the problem that the wheel motor inertia of the whee l motor electric vehicle increases greatly,a logic threshold ABS control model suitable for the wheel motor electric vehicle is established based on Matlab/stateflow,and the orthogonal experiment is designed by SPSS software,and the wheel rotation is obtained.The influence law of the increase in inertia on the threshold value and the optimal threshold value are determined.By adjusting the threshold value reasonably,the braking performance is significantly improved,which has an important reference value for improving the active safety of the wheel hub electric vehicle.(3)Aiming at the problem of the forward load of the axle load caused by the wheel-motor electric vehicle during cornering braking and the threshold of the slip rate of the ABS system under linear braking conditions,it cannot meet the requirements of braking performance and stability under cornering braking conditions.Problem,optimize the slip rate of the ABS system under cornering braking conditions.The particle swarm optimization algorithm is used to optimize the front and rear axle wheel slip rate,and the target slip rate is obtained,which provides a theoretical basis for the control algorithm in ABS under cornering braking conditions.(4)In view of the problem that the mass of the under-spring motor of the wheel hub motor becomes larger,especially under extreme unstable conditions,the wheels can easily reach the limit of the adhesion coefficient,which affects the braking stability of the vehicle.In the existing ABS control st rategy,Based on a few modifications,the coordinated control strategy for vehicle cornering brake ABS and yaw moment is proposed.The upper and lower controllers are designed.The logic threshold ABS control algorithm is studied.The control strategy of s ingle wheel and single side wheel is analyzed.The impact on the vehicle's cornering brake stability.