Active Vehicle Suspension Design Using H∞ Control Technique

Paper in proceeding, 2013

The design criteria of attenuating vertical motion of the vehicle sprung and unsprung masses and suspension deflections make the active suspension control a typical regulator problem and therefore, the linear quadratic regulator (LQR) becomes a suitable candidate. Multivariable technique based on linear quadratic performance criteria with Gaussian disturbance (LQG) has shown good performance provided that the mathematical model of the plant of interest is accurate. Poor robustness of LQG has been observed if either the plant model is not accurate enough or there are various parametric uncertainties of the model. The theory has successfully addressed the robustness issue on the models with parametric uncertainties and unconsidered dynamics through constrained optimisation technique. In this research, a sub-optimal controller is designed for an active suspension system of a quarter-car model. The performance measures of the active suspension are compared with those of the baseline design through numerical simulation. It is shown that the active suspension system is superior to the baseline design in terms of the suspension defections, sprung mass displacements, and the sprung mass acceleration. Moreover, considering the uncertainties of the sprung mass and all the other parameters, the designed controller exhibits its good robustness.