Output-feedback Control for a Class of Uncertain Nonlinear Systems with Linearly Unmeasured States Dependent Growth

This paper is devoted to the problem of global stabilization by output-feedback for a class of nonlinear systems with uncertain control coefficients, stable zero-dynamics, and linearly unmeasured states dependent growth. First, by introducing two kinds of appropriate state transformations, the original system is converted into a new system with deterministic virtual control coefficients and the separated zero-dynamics. Then, a suitable observer based on high-gain K-filters is constructed for the new system, and the backstepping design approach is successfully proposed to the output-feedback controller. It is shown that the global asymptotic stability of the closed-loop system can be guaranteed by the appropriate choice of the design parameters. A simulation example is also provided to show the correctness of the theoretical results and the effectiveness of the proposed approach.