Output feedback adaptive dynamic surface control for a class of uncertain nonlinear systems

In this paper, an adaptive output feedback controller was developed for a class of nonlinear systems with unkonwn parameters, uncertain disturbances and unmeasured states. Firstly estimated states was obtained by introducing an observer. Then a controller was developed based on the dynamic surface control approach. Explosion of terms can be avoided because this method no longer needs the repeated differentiations of the virtue control. Only two parameters instead of all the neural networks weights need to be updated. All the signals of closed-loop systems can be guaranteed semiglobally uniformly ultimately bounded through the analysis of this method. The tracking error can be arbitrarily small by choosing the proper design parameters. Simulation studies show the effectiveness of the proposed approach.