Robust control design for a class of nonlinear uncertain systems with application to missiles

In this paper, we shall extend our study of the “recursive-interlacing” design technique of Kaloust and Qu (1995) to a larger class of nonlinear uncertain systems. The recursive-interlacing design scheme, also referred to “generic design procedure”, is a step by step constructive procedure for designing robust control for nonlinear systems with additive unstructured uncertainties. The design procedure is based on the Lyapunov´s direct method and includes recursive or back-stepping designs as special cases. Nonlinear system under investigation contains uncertainties that do not satisfy any of the previously developed conditions such as the matching conditions, the conditions of being equivalently matched, and the generalized matching conditions. A class of third order nonlinear uncertain systems is introduced for which robust control is designed using the recursive-interlacing design procedure. The need for such a design scheme emanates from the fact that a wide range of physical systems such as missiles belong to this class of nonlinear uncertain systems