Discrete-time static output-feedback H∞ controller design for vehicle suspensions

This paper provides a direct and practical presentation of a novel methodology for static output-feedback controller design. The proposed design strategy has been successfully applied in the fields of control systems for seismic protection of large buildings and multi-building structures, control of offshore wind turbines, and active control of vehicle suspensions. The positive results obtained in these initial applications clearly indicate that this approach could be an effective tool in a large variety of control problems, for which an LMI formulation of the statefeedback version of the problem is available. The main objective of the paper is to facilitate a brief and friendly presentation of the main ideas involved in the new design methodology. To this end, a discrete-time static output-feedback H_∞ controller is designed for a simplified quarter-car suspension system. Numerical simulations indicate that the proposed controller exhibits a remarkably good behavior when compared with the corresponding statefeedback H_∞ controller.