Research On Robust Observation And Fault Tolerant Control For Four-wheel Independent Drive Electric Vehicle

Due to the dual pressure of environmental pollution and energy crisis and the development of motor technology,the electric vehicle is reinvigorated.The four-wheel independent drive(4WID)electric vehicles(EVs)have attracted the attention of the industry because of its advantages and potential in the aspects of structure and control.However,some state information of 4WID electric vehicles is not available and multiple executive actuators bring the high failure rate.These two parts are the important factor hindering their development.Therefore,in view of the above aspects,this paper applies the LPV gain scheduling technology to 4WID electric vehicles,and studies the robust observation of the sideslip and the fault tolerant control for the actuator failures.The main research work is as follows:1.The development and technical characteristics of 4WID electric vehicle are introduced.The research status and existing problems of the sideslip estimate and fault tolerant control are analyzed,and the research strategy of this paper is put forward.Then,the theoretical basis of robust gain scheduling technology based on Linear parameter-varying(LPV)is introduced.2.Considering the uncertainty of the lateral stiffness of the tire and the variety of the longitudinal velocity,the LPV dynamic model of the system is established.By solving the multi-objective problem that satisfies the energy-to-peak performance and closed-loop pole constraint,a sideslip angle observer is designed.The yaw rate which is easy to acquire and the sensor is cheap is used to estimate the sideslip angle which is not available and the sensor is expensive.The observer is robust to the uncertainty and modeling error of the system.3.According to the different types of fault of the motor drive system of 4WID electric vehicle,the fault model is set up.The four control effect on the left and right side of the vehicle are divided into two groups to reduce the design difficulty,and the fault factors of each group are taken as the variable parameters of the LPV system.The vehicle model under the fault condition is transformed into a LPV model.By using LMI technology,the multi-objective problem satisfying H_?performance and closed-loop pole constraint is solved,and a robust fault-tolerant controller is designed.4.The co-simulation platform based on MALAB/Simulink and CarSim for the state observation and fault-tolerant control of 4WID electric vehicles is established to analyse the robust observation and fault tolerance controller performance.5.This paper introduces the 4WID electric vehicle experimental platform,and verified the fault-tolerant controller based on the hardware in the loop simulation system dSPACE.The experimental results show that the vehicle can still track the desired state trajectory and maintain stability and good dynamic performance after the actuator fails.