Research On Bend Braking Force Distribution Control Strategy For Wire Controlled Chassis Platform

The rise of autonomous driving has spawned an unprecedented development of line control chassis,and promoted its subsystem line control system to mass production.The EMB electronic mechanical braking system in this system has become the mainstream in the future with the advantages of rapid response.It should be noted that the unique structure of the EMB system enables it to impose different torques on different wheels,which is convenient for further integration with ABS,EBD,ESP and other brake control systems.This paper studies the distribution of braking force on four wheels under the premise of ensuring the stability of the vehicle for the EMB system on the line control chassis platform.Firstly,the structure and working principle of the line control system are introduced.By introducing the common form of executive mechanism,the structure and function of each component and the typical configuration of some executive mechanism,the structure scheme of EMB executive mechanism is formulated and the functional components are selected.By analyzing the structure and control method of the motor control system,the current,speed and braking clamping force three closed loop PI control system structure suitable for EMB system actuator is determined.Secondly,by analyzing the functional components of the EMB actuator,the simulink models are established.The response requirements of EMB actuator control system are analyzed.The braking efficiency of EMB actuator is improved by using three closed loop PI controller.In particular,the vehicle model is built by dynamic simulation software to detect the correctness of braking force distribution strategy.The control strategy of automatic adjustment of braking gap is proposed to ensure that the same braking gap can be generated after each braking.The simulation results show the effectiveness of the control strategy.Finally,the factors that cause the vehicle to lose stability are analyzed,and the relevant parameters of stability control are obtained.The ideal value of control parameters is obtained by analyzing the 2-DOF vehicle model,and the upper controller is established to calculate the yaw moment caused by the control parameters.The transfer of vertical load of vehicle turning braking is analyzed,especially considering the transfer of load on left and right wheels,and the benchmark braking force of each wheel is designed.The braking force distribution strategy of each wheel considering stability control is proposed;the simulink model of each module is established,and the carsim vehicle model is compared with the traditional vehicle under different working conditions and different road conditions.The simulation results show the feasibility of the proposed control strategy.