OBSERVER DESIGN FOR ELECTRONIC SUSPENSION APPLICATIONS

This paper proposes a new methodology for designing observers for auto motive suspensions. Automotive suspensions are disturbance-affected dy namic systems. Semi-active suspensions are bilinear while active suspe nsions with hydraulic actuators are nonlinear. The proposed methodolog y guarantees exponentially convergent state estimation for both these systems. It uses easily accessible and inexpensive measurements. The f act that sprung mass absolute velocity of the suspension cannot be est imated in an exponentially stable manner with such measurements is als o demonstrated. Controllers using estimated states are implemented exp erimentally on the Berkeley Active Suspension Test Rig. Experimental r esults for two cases are presented: use of observer states to improve ride quality in an active suspension and use of observer states to red uce dynamic tire loading in a semi-active heavy vehicle suspension.