Output-Feedback Stabilization of Uncertain Nonlinear Systems With Multiple Unknown Control Directions via an Integrated Switching Controller

In this paper, the stabilization control problem of uncertain nonlinear systems with multiple unknown control directions is investigated. Firstly, through the coordinate transformation, the original uncertain nonlinear system with multiple unknown time-varying control coefficients is transformed into a simplified system without unknown control coefficients. Subsequently, a dynamic high-gain observer is employed to compensate for the uncertainties in the transformed system. Notably, the proposed integrated switching controller incorporates a candidate set for estimating the control direction, which only contains two elements, greatly shortening the switching process compared to traditional switching controllers. Through the integrated switching scheme, output feedback stabilization of the original system can be achieved despite the multiple unknown control directions. Ultimately, several numerical simulations of a DC motor electrical model are conducted to show the effectiveness of the presented integrated switching control strategy.