Synthesis of model-free control for system with time-varying communication delay

Nowadays, the model-free control scheme has led to numerous convincing applications. However, the applications of model-free control in Networked Control System (NCS) is still limited because of its weakness to process the time-varying delay which usually appears in this type of networks. This paper proposes a new method to adapt model-free controller to improve its use in NCS. This method suggests a new structure of model-free control. The main idea is based on mutual benefit between Smith predictor and the basic model-free controller. The basic model-free control will provide the required information about the plant model which will make Smith predictor free from any model information requirements. On other hand, Smith predictor will move the effect of time delay outside the closed loop of model-free control. The test result of the proposed method shows that the method can significantly help to synthesis of model-free control in NCS.