Stochastic control of semi-active suspension system

In this paper, for automobile semi-active suspension in rough road, the problems of random modeling and control are considered. First, dynamics model is constructed assuming the road being flat. According to the dynamic-static method and the relative-motion principle, the road irregularities is transformed to disturbance to the control. Thus, the random dynamic model of the system is established. Second, the system is transformed into a lower triangular system by an appropriate transform. Using backstepping method and Lyapunov theory, a controller is designed such that the closed-loop system is noise-to-state stability in probability(NSS-P) and the mean square of the state converges to an arbitrarily small neighborhood of zero, which means that the passengers feel much comfortable. Finally, the simulation experiment is carried out by Matlab. The simulation results show the effectiveness of the control strategy.