Robust nonlinear feedback control with nonquadratic performance criteria

In this paper we develop a unified framework to address the problem of optimal nonlinear robust control. Specifically, we transform a given robust control problem into an optimal control problem by properly modifying the cost functional to account for the system uncertainty. As a consequence, the resulting solution to the modified optimal control problem guarantees robust stability and performance for a class of nonlinear uncertain systems. The overall framework generalizes the classical Hamilton-Jacobi-Bellman conditions to address the design of robust optimal controllers for uncertain nonlinear systems