Robust controller design of a semi-active quasi-zero stiffness air suspension based on polynomial chaos expansion

Abstract

Air suspension is one of the heart of electrified chassis, which plays a key role in vehicle ride comfort, driving stability and safety. In order to further improve the suspension performance to meet the demand of complex and changing road conditions, various new suspension structures have emerged. This paper inherits the advantages of electronically controlled air suspension and proposes a quasi-zero stiffness air suspension system combined with pneumatic negative stiffness mechanism. Aiming at the random uncertainty of the structural parameters of the suspension system due to manufacturing, use environment and wear, a robust controller for a semi-active quasi-zero stiffness air suspension based on polynomial chaos expansion (PCE) is designed. The quasi-zero stiffness air suspension alternative model is established by the coefficient state equation of PCE, and the state feedback control law considering the random parameter uncertainty is obtained based on the H2 control theory solution. Simulations and HiL tests are conducted to verify the effectiveness and real-time performance of proposed PCE-H2 controller. Simulation results show that the performance of PCE-H2 control law is better than that of the conventional H2. The HiL results also show that the PCE-H2 control law considering uncertainty is 3.2% less effective than the conventional H2 control law in overall performance of the suspension. Besides, the control effect of the PCE-H2 control law is 38.7% better in the performance maintenance of the semi-active suspension.