Guaranteed cost LPV output-feedback controller design for nonlinear systems

This paper proposes a guaranteed cost linear parameter-varying (LPV) output-feedback controller for nonlinear systems. Interpolating a nonlinear system into an LPV system associated with time-varying and state-dependent weighting functions, i.e. the gain-scheduled parameters, allows one to apply various linear system theories and techniques for analyzing and synthesizing nonlinear systems. Consequently, with the real-time measurable time-varying parameters, this paper presents an affine type of linear parameter-dependent output-feedback controller, i.e. an LPV controller, for the given LPV plant. As a cost, we consider an upper bound of states and input energy called LQ performance, under all admissible grades of the gain-scheduled parameters. This approach is more flexible for the nonlinear systems than existing approaches in the literature because the other controllers excessively depend on the structure of the nonlinear systems.