Observer based design of a nonlinear H∞ output feedback controller for linear systems with nonlinear weights

This paper gives a design method of a nonlinear output feedback controller for linear systems. In order to design a nonlinear controller, we use nonlinear weights and consider the nonlinear H_∞ control problem. In this paper, we assume that the nonlinear weights are functions of the observer variable. Under some constraints on nonlinear weights, it is shown that the nonlinear H_∞ controller is derived by solving the algebraic Riccati inequality. This paper also derives nonlinear weights which satisfy the constraints