FUZZY-LOGIC CONTROL OF VEHICLE SUSPENSION SYSTEMS

Passenger fide comfort has been one of the major issues of vehicle des ign. The most efficient way of achieving better ride quality is to imp rove the control of vehicle suspension systems. This paper focuses on developing a robust control algorithm for vehicle suspension systems w hich can handle a wide range of road roughness as well as mechanical v ariances of suspension systems while providing a comfort ride. Specifi cally, a model reference self-tuning fuzzy logic control scheme which consists of a primary and a secondary controller is proposed. The prim ary controller performs the major control function of the actual sprun g mass acceleration. The secondary controller, however, is used to tun e the output membership function of the primary fuzzy logic controller on line such that it is capable of adapting process variations such a s sprung mass change, spring and damper rate variations and harsh road conditions. The simulation results show that the proposed fuzzy logic controller can make the active suspension system accommodate normal r oad condition variations and provide near-zero sprung mass acceleratio n, which in tum yields good quality fide. The comparison study through simulation also demonstrates the superior robustness of the proposed controller over the conventional controller for active vehicle suspens ion systems.