Adaptive output feedback control of nonlinear systems with input unmodeled dynamics

In this paper, an adaptive dynamic surface control scheme is proposed for a class of output feedback systems with input unmodeled dynamics. By constructing the state observer, unmeasurable states are estimated. By introducing the first order filter in traditional backstepping design, the repeated differentiations of virtual control is avoided. Using dynamic surface control, the disturbances induced by input unmodeled dynamics and unknown continuous function are effectively dealt with. By theoretical analysis, it is shown that all the signals in the closed-loop system are semi-global uniformly ultimately bounded.