Nonlinear H∞ control and the Hamilton-Jacobi-Isaacs equation

This paper considers two aspects of the nonlinear H∞ control problem: the use of weighting functions for performance and robustness improvement, as in the linear case, and the development of a Galerkin approximation method for the solution of the Hamilton-Jacobi-Isaacs Equation (HJIE) that arises in the output feedback case. Design of nonlinear H∞ controllers obtained by Taylor approximation and by the proposed Galerkin approximation method applied to a magnetic levitation system are presented.