Fuzzy Immune PI Control of Networked Control System Based on ADW Time-Delay Prediction

The time-delay induced by network in control system is an important factor that affects system stability and dynamic performance. An arithmetic composed of Smith prediction compensator and fuzzy immune PI controller is designed to compensate the time-delay of the networked control system. Average delay window (ADW) is used to predict the current network time-delay which is compensated by the Smith compensator. In this manner, for the existing of prediction error caused by ADW, the Smith compensator can not compensate the delay absolutely. Therefore, the immune PI controller is applied to enhance the Qos of the networked control system. In this controller, the coefficients of PI controller are regulated according to the control input. If parameters and nonlinear function are chosen properly, the performance of the system can be improved. Simulation results show that the proposed approach can minish the overshot and response time, and make system more robust in great disturb and uncertain environment.