On Sampled-Data Observer Design for Nonlinear Systems

Sampled-data observer is an important issue of control theory while most implemented control systems are based on computer control. This paper studies sampled-data observer design for nonlinear systems. Because of the difficulties to get the exact discrete-time model of the nonlinear plant the design is based on the approximate discrete-time model. The continuous-time model of the plant is discretized by Euler´s method and the observer feedback item is designed in discrete-time. Then the observer is constructed of the feedback item and a more precise approximation. Theory analysis gives the conditions under which the observer will work well for the unknown exact discrete-time model. The theory is illustrated by simulation results.