Analysis And Simulation On The Control Strategy Of The Electric Hydraulic Brake System

The Electric Hydraulic Braking system(EHB)on automotive improved the structure of conventional hydraulic brake system combining with the characteristics of the automotive control-by-wire technology.The EHB system canceled the vacuum booster instead of using a high-pressure accumulator to provide the brake pressure.The structure of the EHB system determined its high controllability.When matching with different vehicles,the EHB system just need do some modifications on the algorithm after the parameters calibration.Meanwhile,the characteristics of EHB system like highly efficient,energy-saving are adapted to the current trends in vehicle development.The ECU of the EHB system identify the driver's braking intention by processing the electronic signal from the brake pedal,then send the corresponding brake singal to HCU to establish or release the brake pressure,which is significantly different from the traditional brake system.Thus,the performance of the control system has great impact on the braking effect of the vehicle.In this paper,the following work is done based on the principle and working mode of EHB system:(1)Established EHB system simulation model in AMESim,then established the system pressure control model based on feedback control theory in the Simulink software,achieved effective pressure control of the EHB system through a joint simulation.(2)Established the pressure control model based on PID algorithm,analysised the impact of the PID's parameter on the system,then selected the most appropriate parameters to optimize the effect of the control system,made the EHB system has faster response and higher accuracy.(3)Runed a simulation of the EHB system combine with the 7 DOF half vehicle in AMESim.Evaluated the EHB system by three kinds of braking conditions.The results show that the EHB system has good pressure controllability.(4)Performed a preliminary study on the EHB system integrated with ABS control,established ABS control state transition graph in stateflow,completed of the anti lock braking simulation based on EHB system.