Robust H∞ control for an active suspension system

This paper provides a robust state feedback controller applied for an active suspension system. The controller presents guaranteed capacity to reject disturbances from the road even when the sprung mass of the vehicle is uncertain. The control gains are given from the solution of the H
_∞
guaranteed cost controller under quadratic stability, which is solved very fast and efficiently from a convex optimization problem. These gains provide robust stability and robust performance when the uncertain parameter is time-invariant, but are also valid for the arbitrarily time-varying situation, since the results are based on a quadratic Lyapunov function. The time and frequency responses presented, with a comparison with other controller for the active suspension system with the same parameters, illustrate the superiority of the proposed controller.