Research On Sliding Model Variable Structure Control Method Of Electronic Brake Booster

Automobile intelligence enables the car to determine the current optimal solution through the control system,thereby reducing dependence on the driver.The electric brake booster system that relies on the motor to achieve the power-assisted function is undoubtedly the best solution for the new energy vehicle braking system And the system also has an active braking function,which can work in coordination with ABS,ESP,AEB and other systems,as the lowest level actuator of the intelligent driving assistance system function.Relying on the horizontal project "Electric Brake Booster System Design and Development" commissioned by the enterprise,it focuses on the study of the control strategy of the electric brake booster system,combined with the structural scheme design of the electric brake booster system,the control strategy design of the booster motor,and the electric A series of researches were carried out on the modeling of the mechanical transmission of the brake booster and the brake master cylinder,and the co-simulation analysis with the CarSim vehicle model.The main contents of this paper are as follows:(1)Introduce the working principle and mathematical model of the main components of the electric brake booster system in detail,and propose a self-designed electric brake booster system structure scheme;analyze the boost strategy framework of the electric brake booster system,and draw the conclusion of the power-assisted motor The control strategy research is the key to realize the basic power-assisted braking function of the electric brake booster system.(2)A three-loop PID control strategy suitable for the electric brake booster system is designed.Aiming at the disadvantages of PID control such as weak anti-interference ability and poor control robustness,the sliding mode variable structure control algorithm is used to analyze the sliding mode variable structure.The basic principles of control,the speed and position sliding mode variable structure controllers are designed based on the exponential reaching law control method,and the Lyapunov asymptotic stability of the sliding mode controller is proved;Comparing the conventional sliding mode control algorithm based on the exponential reaching law and PID control algorithm,the results show that the sliding mode variable structure control strategy can improve the speed and position following accuracy of the system.(3)Aiming at the chattering problem in the sliding mode variable structure control based on the exponential reaching law,an improved sliding mode variable structure control strategy in which the boundary layer thickness can be adaptively adjusted according to the real-time state of the system is designed using a fuzzy controller.The parameters of the fuzzy controller are designed,so that the improved sliding mode variable structure control strategy has been optimized in terms of speed and position tracking performance and reduction of system chattering,and the control robustness has been strengthened.(4)The mechanical transmission structure and brake master cylinder model of the electric brake booster system were established.The electric brake booster system of the mechanical transmission structure and the brake master cylinder model is simulated under two typical braking conditions,the hydraulic pressure of the master cylinder and the position follow-up control simulation of the screw rod.Build a joint simulation model of the electric brake booster system and the CarSim vehicle,and conduct joint simulations under two typical braking conditions.Realize the basic power-assisted braking function of the electric brake booster system.Verify the superiority of the improved sliding mode variable structure control strategy in anti-buffing and enhancing system stability.