This paper investigates the robust stabilization problem of a class of uncertain nonlinear systems with input matching uncertainty under linear feedforward growth conditions. Smooth robust controllers are obtained by state feedback and output feedback, respectively. In order to deal with input matching uncertainty, extra dynamics are designed inspired by the integral control and disturbance estimation. The proposed controllers guarantee that the states of controlled systems asymptotically converge to zero and all closed-loop signals are globally bounded. Finally, an example is given to illustrate the usefulness of the state-feedback and output-feedback controllers proposed.

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In this paper, the problem of global decentralized output feedback control is addressed for a class of large-scale nonlinear systems with zero dynamics and unknown time-varying delay. System disturbance nonlinearities are subject to feedforward growth restrictions with unknown growth rate. In the spirit of dynamic scaling change technique, a novel pair of time-varying-gain observer and controller is proposed. Compared with the existing results, the controller proposed is capable of handling the difficulties caused by the zero-dynamics, the uncertainties and the unknown time-varying delay. With the help of the Razumikhin theorem, it is shown that the closed-loop states asymptotically converge to zero. Finally, the effectiveness of the proposed control scheme is illustrated by a numerical example.

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