Design of H/sub /spl infin// controllers for affine nonlinear uncertain systems

In this paper we consider the H/sub /spl infin// control for an affine nonlinear uncertain system. We show that the original H/sub /spl infin// problem can be reduced to an H/sub /spl infin// problem without uncertainty; and by taking quadratic functions satisfying Hamilton-Jacobi-Isaacs inequalities for the H/sub /spl infin// control problem, we give /spl gamma/-suboptimal state feedback controllers and the domain of their validity. We then construct /spl gamma/-suboptimal output feedback controllers and also give the domain of /spl gamma/-disturbance attenuation.