Linear quadratic Gaussian regulator design for a half car vehicle model

This study deals with the control of active and semi-active automotive suspensions using LQG techniques. An analytical investigation of a half car model subjected to random road disturbances is performed, and the advantages of the active suspension systems, over conventional passive suspension systems are examined. In this study in order to investigate the ride and handling characteristics of a car, a two dimensional mathematical model with a suitable road profile are developed, and the equations of motions for the proposed model with four degrees-of-freedom are derived. The controller design is proposed to minimize the chassis and pitch angle acceleration with suspension and tire deflections when uneven road surfaces are acting on the tires of running car. Measurements from sensors located at different points of the vehicle are controller inputs and the control forces generated at each wheel of the suspension are outputs of the controller. In the conclusion, a comparison of active suspension with LQG controller and passive suspension is made using MATLAB simulations. Simulations are performed to show that actively controlled suspensions succeeds in achieving higher levels of ride comfort and drive safety with respect to a passive setting. Keywords: Active suspensions, LQG controller, Vehicle dynamics, One-half car model, Ride comfort