MODEL MATCHING AND TARGET FOLLOWING CONTROLS FOR NONLINEAR DISCRETE TIME SYSTEMS: STABILITY OF CONTROLLER

摘要

The author has recently presented two methods of control system design for nonlinear discrete time systems. One is a model matching control (MMC) which makes the characteristics of the closed loop system identical with that of a desired model. Other is a Target Following Control (TFC) method which makes a system output coincides with that of a desired system. As in other design method, MMC and TFC depend on the stability of the controller. It is well known that the non-minimum phase system in linear case is not easy to be controlled. It is proposed here to use purposely modified values in the controller in order to obtain a stable controller, and then stable system at the cost of model error if the system has unstable zeros. Some simple method is presented in this paper to obtain a stable controller.