Multiobjective optimal suspension control to achieve integrated ride and handling performance

A multiobjective optimal control strategy is pursued for finding feedback control laws used in controlled suspensions for automotive vehicles. The balanced vehicle ride and handling performances are the main concern of the paper. The ride performance (car body performance) is characterized by an H₂ system norm, and the handling performance (wheel performance) is characterized by an H_∞ system norm, and the control method optimizes the mixed H₂/H_∞ performances. The H₂ and H_∞ system norms used in the mixed H₂/H_∞ performance optimization are scaled by the corresponding open-loop norms such that the relative importance of the individual variables can be reflected in the performance index for the vector variables. The comparison between passive and controllable suspensions shows in simulation the advantages of this optimal control strategy. The simulation result also shows that the invariant point for controlled suspensions in the quarter car case exists in the seven degree-of-freedom model.