A Sampled-Data Scheme for Adaptive Control of Nonlinear Systems

The paper considers sampled-data control for a class of nonlinear systems in parametric strict-feedback form. For such a system, a continuous-time adaptive controller can always be designed using backstepping. When the direct discretization of this continuous-time controller is applied to the same system via a sampling and hold device, however, the stability of the resultant sampled-data system cannot be guaranteed. This paper presents a sampled-data control scheme which involves first modifying the existing continuous-time controller and then discretizing it using the forward Euler method. It has been shown that the proposed control guarantees in a semiglobal sense the boundedness of all the variables of the overall sampled-data system.