Defl ection adaptive LPV control of an active suspension system

The conflict in the design of automobile suspension systems between ride-comfort, safe driveability in the sense of low dynamic wheel loads and limited suspension deflection can be eased by active suspensions. The versatility and performance of an active suspension system is further increased if its controller parametrization is adapted to the current driving state. This can be achieved by interpreting the parameter of a linear parameter varying (LPV) controller as a scheduling variable. In this paper an LPV controller is synthesized that establishes quadratic ∞_∞-performance γ of the generalized plant. Smooth scheduling between two controller settings is performed depending on the output of an adaptation logic that processes the suspension deflection signal. The intention is to design a comfort maximizing controller, which also satisfies safety and suspension stroke constraints. The focus is on preventing excessive suspension deflections for low-frequency road excitations, which are a problem for most conventional ride comfort oriented controllers if real measured road profiles are used as excitation.