Adaptive Observer for Active Automotive Suspensions

An adaptive observer for a class of nonlinear systems is developed. Conditions for convergence of state estimates and parameters are presented. The developed theory is used for observer-based parameter identification in the active suspension system of an automobile. The observer uses measurements from two accelerometers and an LVDT. It adapts on dry friction which is usually present in significant magnitudes in hydraulic actuators of active suspensions. Experimental results on a half-car suspension test rig are presented.