Research On Vehicle ABS/ESP And Coordinated Control

The stability of the vehicle driving is closely related to safety.The longitudinal,lateral and yaw motions of the vehicle and the rotation motion of the four wheels around their respective central axes are controlled by designing effective control algorithms of Anti-lock Braking System(ABS)system and Electronic Stabilization Program(ESP)system,and the driving stability of the vehicle is improved by the ABS/ESP coordinated control reasonably.The thesis introduces the research status and development trend of chassis active safety control algorithm,and analyzes the development status,working principle and basic structure of ABS and ESP systems.The two-degree-of-freedom model is established as a reference model,and then the seven-degree-of-freedom model,the body model,the Dugoff tire model,and the brake system model are established.The theory of vehicle braking is analyzed,and the principle of controller applied to ABS is introduced separately.The thesis studies the control algorithm with the slip rate and simulation,at the same time,the simulation results are analyzed to some extent.PID control and fuzzy PID control algorithm based on road surface identification can improve the vehicle braking performance,which is better than the uncontrolled braking effect.The fuzzy PID control based on road surface identification is determined to research the ABS/ESP coordinated control.Subsequently,the thesis analyzes the vehicle manipulate stability,selects the single-side wheel brake control strategy and studies the braking force distribution.The vehicle center-of-mass side slip angle is estimated by the classic Kalman filter theory,which is simulated and analyzed in specific working conditions.The real-time parameters of vehicle are obtained by the vehicle test system developed in the laboratory,which verifies the practicability of the established model and the validity of the simulation model.According to the model established in thesis research,the ESP controller based on PID control,integral separation PID control and fuzzy PID control is studied.The simulation is carried out on the high and low adhesion roads under double-shifting and sinusoidal conditions.The ESP controller by fuzzy PID control is adopted to research on ESP and ABS coordinated control.Finally,the ABS/ESP coordinated control strategy is designed,which is simulated and analyzed by non-control,ABS individual control,ESP individual control,ABS and ESP coordinated control under double shift line conditions and sinusoidal conditions.When ABS individual controls,the simulation results has better braking effect on the vehicle and the braking time is shortened.When ESP individual controls,ESP only has better steering stability for the vehicle.When ABS and ESP coordinated control,not only the braking performance can be improved,but also braking and steering stability can be increased.