Fault Estimation?Compensation And Fault Tolerant Controller Design For The Active Suspension System

Active suspension system consists of passive suspension,sensors,controller and actuator,where the night of the vehicle,lateral state,and vibration are first measured by the sensor and then transferred to the electric control unit.Then,the output control force is calculated according to the signals detected by the sensor.And finnally the actuator assembled in active suspension system is able to generate the corresponding control forces with dissipating some energy to improve the pertormance of the active suspension system.However,it is fairly common to encounter various faults in the real-world vehicle suspension system,especially faults from actuators and sensors.And such faults would usually result in performance degradation,instability,or catastrophic events for vehicle suspeAsion system.In order to improve the safety of the active suspension system,the following half vehicle fault tolerant control strategies are developed based on the obserever theory and robust control theoiy in this thesis.(1)The model establislhment of active suspension faulty system.Based on the Newton's second law,the differential equation and the state equation for the active suspension system are first established.Considering that the stiffness and damper coefficient of the suspension are nonliearity,the nonlinear model of the active suspension system is then established.Besides,considering that the faults may occur in the active suspension system,the actuator fault model of the active suspension system is established as well.(2)Design ot a robust H? observer-based fault tolerant controller for nonlinear active suspension subjected to actuator faults and external disturbances.Based on the nonlinear faulty active suspension system,a composite control structure is presented to stabilize the control plant with guaranteeing its asymptotic performance under aitterent actuator fault mode,in which,a nominal module is designed as a H? state feedback controller to keep the suspension performance without the actuator fault,and a compensation...