Constrained H _∞ control for active suspensions

In this chapter, the quarter-car model is mainly adopted to develop H _∞ optimal control method. On account of its good disturbance attenuation performances and strong robustness, H _∞ control scheme is relatively efficient to be utilized in active suspensions. In Sect. 2.1, a traditional H _∞ control method in the entire frequency domain is elaborated. The minimum H _∞ norm from the disturbance of the closed-loop system to the vehicle body acceleration is searched for by convex optimal method in order to get the controller gain with the best disturbance attenuation ability and satisfy corresponding performance constraints. In Sect. 2.2, a load-dependent controller design approach is presented to solve the problem of multi-objective control for vehicle active suspension systems. It is assumed that the vehicle body mass whose value changes with the vehicle load resides in an interval and can be measured online.