Robust adaptive control of uncertain nonlinear systems with time-varying parameters

In this paper, we present robust adaptive control schemes of partially linearized uncertain nonlinear systems with time varying parameters. For nonlinear parametrization and linear parametrization, two adaptive controllers are constructed via a static state feedback and a dynamic state feedback, respectively. In order to guarantee the robustness of the overall control methods, a modification of adaptive backstepping is proposed with various powerful functions. By presented schemes, we can achieve robust regulation of the output by appropriate choice of design constants while maintaining boundedness of all the signals and states.