Design Of Fault Tolerant Controller For Active Suspension System Based On T-S Fuzzy Model

Due to the development of industrial society,the design of suspension control system is more and more complex with the increasing types of components.And such components will inevitably encounter various faults in the real world because of fatigue and aging.Therefore,In order to improve the safety of the active suspension system,fault-tolerant control becomes an indispensable part for suspension controller design.In this thesis,a quarter and half vehicle active suspension models are respectively established.Different types of controllers are designed to improve the system performance of the suspension system under fault conditions,which can be summarized as follows:(1)Analysis of the smoothness of passive suspensionBased on the Newton's second law,the state-space equation for the passive suspension system is first established.Then the simulation is conducted under three different road surfaces,where the vehicle vertical acceleration,suspension dynamic deflection and tire dynanmic load are used as evaluation performance indicators.Finally,the simulation data is usecd for the follow-up research of active suspensiorn;(2)Research on T-S fuzzy control of onlinear active suspension systemAccording to the fuzzy control,the T-S fuzzy models with different degrees of freedom of the suspension system are established to resolvte the problem of uncertain active suspension systenm;(3)Research on sliding mode fault-tolerant control for the active suspension based on T-S fuzzy modelTo resolve the problem of riding comfort and control stability caused by the variation of the stochastic actuator faults,a passive fault tolerance controller design method is proposed based on T-S fuzzy model of quarter vehicle active suspension,which can make the system insensitive to failures.And the feasibility of the sliding mode fault-tolerant controller is verified by simulation;(4)Research on a proportional-integral observer(PIO)based fault tolerant tracking controller(FTTC)Based on the T-S fuzzy model of half vehicle active suspension,a proportional-integral observer-based fault tolerant tracking controller design method is proposed to address the challenging issue brought by the underlying actuator deviation faults.Firstly,a nominal robust H? output feedback controller is developed to enhance the suspension performances under normal actuator mode,whose output responses are taken as the ideal reference trajectories.Subsequently,the proportional-integral observer is designed to accurately estimate the actuator fault online and then the PIO-based FTTC is synthesized and implemented to compensate for the performance penalties caused by the actuator faults.Finally,a numerical example is provided and the simulation results show that the proposed FTTC can well satisfy the tracking performance requirements for active suspension system.