The Control Strategy Of Braking Force Distribution For Automotive Electromechanical Braking System

Automobile electromechanical braking system,which uses a motor to provide braking force to the vehicle and implements braking.Signal lines and sensors replace hydraulic lines to simplify the entire vehicle braking system.The structure is compact and easy to integrate into the vehicle's electronic communication network.Combined with ABS,ESP and other control methods.Due to the rapid response,stable performance,energy saving and environmental protection of the electromechanical braking system,it has become a new direction for the research of braking systems.This paper mainly studies how to make reasonable allocation of the car braking force on the four wheels of the dynamic system car..First,the overall structure and working principle of the wire control and actuation system are introduced.Aiming at the target vehicle,a matched EMB actuator was designed and its physical characteristics were analyzed theoretically.The simulation model of the brake was established.A three-closed-loop control system based on the PI control method is used to improve the braking performance of the brake.Use CarSim software to build a car model to prepare for simulation of braking force distribution strategy.Secondly,based on the fact that the wheel braking force is proportional to the vertical load of the wheel,the braking force distribution strategy of the car on the straight road is proposed.Due to the existence of vertical load estimation error and the change of vehicle weight,a method of adjusting the braking force according to the difference in wheel speed was proposed.The braking force was reasonably distributed so that the wheel speed of each wheel was nearly equal.A simulation model for the distribution strategy of the straight braking force was established.The simulation results showed that the effect of the distribution strategy of the straight braking force was ideal.At last,the reasons of the influence of braking on the stability of vehicle corners are analyzed.The PID controller of the braking stability of the curve is designed with the yaw rate and the lateral slip angle as the control variables.The curve braking is designed based on the method of the distribution of the straight braking force.The base brake torque distribution,through the target wheel brake torque control strategy to achieve bending force distribution and stability control.Simulations were conducted on dry asphalt pavement and wet asphalt pavement in two driving conditions.The results demonstrated the effectiveness of the braking force distribution and braking stability control strategies for vehicle corners.