Output feedback stabilization of time-delay nonlinear systems with unknown continuous time-varying output function and nonlinear growth rate

This article addresses the problem of global output feedback stabilization for a class of time-varying delay nonlinear systems with polynomial growth rate. The systems under investigation possess two remarkable features: the output is perturbed by an unknown sensitivity function that is not differentiable but continuous, and the nonlinearities are bounded by a polynomial function of the output multiplied by unmeasurable state variables. The new full-order observer is established by introducing a dynamic gain and filtering unknown nonlinearities and time-varying delay. With the help of the transformation skill and the reasonable combination of several systems, this article proposes a linear output feedback controller with the dynamic gain and completes the performance analysis based on the construction of two integral Lyapunov functions. Finally, a simulation example is presented to demonstrate the effectiveness of control strategy.