Stabilization of MIMO Nonlinear Systems with Uncertain Input Gain: Nonlinear Nominal Gain Function

Abstract

This paper deals with the output feedback stabilization problem of nonlinear multi-input multi-output systems having uncertainty in the input gain matrix. The nonlinear system under consideration is assumed to have a well-defined vector relative degree and we allow the nominal function of the input gain matrix to be a nonlinear function so that a wider class of practical systems such as Euler-Lagrange systems can be covered. To solve the problem, a new controller structure is proposed and it is shown that the origin of the closed-loop system can be made semi-globally practically stable.