Adaptive neural network control of uncertain nonlinear systems with nonsmooth actuator nonlinearities

In this paper, we present a new approach of designing adaptive neural network controllers for uncertain systems containing nonsmooth nonlinearities in the actuator device. The controllers are designed by introducing certain well-defined sign functions and neural network approximations as well as by using the backstepping technique. The salient feature of the approach is that no knowledge is assumed on unknown system parameters and nonlinearities. It is shown that the proposed controller not only can guarantee semi-global stability, but also excellent transient performance can be achieved.