Adaptive anti-windup approach for vehicle semi-active suspension

In order to deal with the saturation problem of semi-active suspension systems in presence of a feedback controller, an adaptive anti-windup approach is introduced. Once the control signal exceeds the damper limitation, instability of the closed loop may occur. To ensure that the control signal is kept within the saturation range, an anti-windup controller is designed to maintain the closed loop stability of a robust optimal feedback controller. A Non-Model based Adaptive Controller (NMAC) is used together with the optimal feedback controller to cope with system uncertainties and nonlinearities. The proposed approach is applied to a quarter-car model with a semi-active damper, where nonlinear spring stiffness and nonlinear damper saturation are adopted. Simulation and experimental results have shown a significant improvement regarding the control performance.