Taming internal dynamics by mismatched and H∞-optimized state observer

The feedback linearization control scheme is simple but quite effective for control of a single-input single-output (SISO) linear parameter-varying (LPV) plant. When the relative degree of the plant is less than its order, the feedback linearization control scheme generates the internal dynamics, which may or may not be stable. The paper presents the design methodology of a state observer that not only provides the feedback linearization controller with good estimation of state variables of the plant, but also stabilizes the overall closed-loop system. We propose to make the choice of system matrices of the state observer completely open in order to search for such an observer structure. Two application examples, including application to steering control for lateral motion of heavy-duty vehicles, are presented to illustrate how the proposed mismatched observer stabilizes the closed-loop system