Dual-rate sampled-data H∞ control for vehicle active suspension systems

This paper investigates the problem of dual-rate sampled-data H_∞ control for a vehicle active suspension system. In the system, the state variables are sampled by two types of sensors, and the ratio of two sampling rates is assumed to be a positive integer. Depending on whether the sampled states at two sampling rates are available simultaneously or separately, a periodic switched controller is proposed. Then, by using an input delay approach, the closed-loop system is modeled as a switched system with different input delays. A delay-dependent criterion on the existence of the switched controller is established such that the system is exponentially stable with a prescribed H_∞ performance. The effectiveness of the proposed method is shown by a numerical example.