A DSC Based Adaptive Control Scheme for A Class of Uncertain Non-lower Triangular Nonlinear Systems

An adaptive tracking controller design method is developed for a class of nonlinear systems with non-lower triangular form and linear parameterized uncertainties by combining backstepping and dynamic surface control (DSC) technology. In the design, traditional backstepping design process is used to establish control laws recursively, and unknown parameters of control laws are estimated online. By using DSC technology, the problem of circular structure of the controller is eliminated. Stability results of closed-loop system show that the uniform ultimate boundedness of closed-loop system signals can be guaranteed. Besides, the steady state tracking error of the system can be adjusted to a small neighborhood of zero by selecting appropriate control parameters. The efficacy of the designed approach is demonstrated via a numerical simulation example.