SLIDING-MODE FAULT TOLERANT CONTROLLER DESIGN FOR VEHICLE ACTIVE SUSPENSION SYSTEMS BASED ON T-S FUZZY MODEL

To resolve the problem of riding comfort and control stability caused by the variation of vehicle suspension sprung masses and the stochastic actuator faults, a novel sliding-mode fault tolerant controller design method is proposed for vehicle active suspension systems based on T-S fuzzy model. To describe the system parameter uncertainties of active suspensions, a quarter-vehicle nonlinear dynamic model based on T-S fuzzy approach is first established, in which a fault tuning factor is employed to denote the amplitude of actuator faults, thus the control plant of vehicle active suspension with considering the uncertainties of vehicle suspension sprung body masses and the actuator faults is obtained. Based on this control model, an appropriate sliding-mode surface function and fault tolerant control law are developed to realize the fault tolerant control of the fault suspension system through the combination of classical sliding control theory and adaptive control theory. Moreover, the stability analysis and suspension safety constraint performances are carried out by Lyapunov stability theory. Finally, a numerical example is provided to verify the effectiveness and applicability of the proposed fault tolerant controller under different road conditions.