Research On Brake-by-wire Control Strategy Of ESC

With the rapid development of Chinese economy,the per capita ownership of automobiles has also increased rapidly,and driving safety has become one of the key research directions of Chinese automotive technology.As one of the active safety products of automobile,ESC brake by wire system can reduce the occurrence of automobile accidents by controlling the braking pressure or de celeration.In this paper,the ESC brake by wire system is taken as the research object,and a compound pressure control strategy which combines ESC pressure increasing and reducing characteristics,logic threshold control and fuzzy control is put forward,and a compound deceleration control strategy which takes vehicle longitudinal dynamics model as feedforward and PID control as feedback is put forward,which has the advantages of low cost,high precision and function expansion.The research content to be carried out in this paper is as follows:Starting from the working principle of ESC hydraulic execution unit,the mathematical model of key hydraulic components is built,and the ESC hydraulic braking system model is built in AMESim,which lays the foundation for the research of pressure control strategy of line control hydraulic system.Through the experimental calibration method,the relationship between PWM of motor and pressure limiting valve,pressure of wheel cylinder and the speed of increasing and decreasing pressure is analyzed,and the active brake pressure control strategy is designed,and the effectiveness of the designed pressure control strategy is verified by AMESim and Simulink joint simulation experiment.Using the vehicle dynamics knowledge to build the mathematical model of the key components of the whole vehicle braking system,and build the vehicle braking system model in CarSim,which lays the foundation for the research of the deceleration control strategy of the line control braking system.The active braking deceleration control strategy is designed,and the effectiveness of the designed deceleration control strategy is verified by the joint simulation experiment of Car Sim and Simulink.By building a real vehicle experiment platform,the pressure control strategy and deceleration control strategy of ESC by wire brake system proposed in this paper are studied.The results show that the pressure control strategy and deceleration control strategy proposed in this paper can make the actual pressure and actual deceleration follow the target pressure and target deceleration very well,with fast response time and high control accuracy.