Adaptive control of a class of second order nonlinear systems with convex/concave parametrization

This paper deals with adaptive control of a class of second-order nonlinear systems with a triangular structure and concave/convex parametrization. In the paper by Annaswamy et al. (1998), it was shown that nonlinearly parametrized systems that satisfy certain matching conditions can be adaptively controlled in a stable manner. In this paper, we relax these matching conditions and include additional dynamics between the nonlinearities and the control input. Global boundedness and convergence to within a desired precision /spl epsiv/ is established. No over-parametrization of the adaptive controller is required.