Robust control for nonlinear systems with uncertain time-varying parameters coupled with non-triangular terms

摘要

In this paper, a robust control scheme is proposed for a class of nonlinear systems which consist of uncertain time-varying parameters that are coupled with non-triangular terms, perturbed nonlinearity, and external disturbance. In order to deal with time-varying parameters, we provide determination process of allowed time-varying parameters utilising a Lyapunov equation. With system analysis associated with perturbed nonlinearity, we show that all states of the controlled system remain bounded by a gain-scaling feedback controller in the presence of external disturbance. Moreover, the ultimate bounds of some system states can be made (arbitrarily) small by adjusting a gain-scaling factor depending on the system nonlinearity. The effectiveness of our control scheme is shown via an application example, with comparison of the existing result.