Abstract
Suspension plays an important role in vehicle chassis related to riding comfort and handling. In order to improve those two simultaneously it necessitates a demand on several kinds of electronic controlled suspensions. In this paper the design of sliding mode controller is studied using singular perturbation method for 1/4 car semi-active suspension model. By singular perturbation method the full order system is separated into slow subsystem related to sprung mass and fast subsystem related to unsprung mass. With this model reduction sliding mode controller is designed and applied easily. To verify the effectiveness of the proposed algorithm, experiments have been conducted including comparison with other control algorithm and parameter variation.