New Smith Predictor and Nonlinear Control for Networked Control Systems

In order to effectively restrain the impact of network delay for the networked control systems (NCS), a novel approach is proposed that new Smith predictor combined with nonlinear PID control for the NCS. This approach can adaptively tune parameters of the nonlinear PID controller. Because new Smith predictor hides predictor model of the network delay into real network data transmission process, further the network delay no longer need to be measured, identified or estimated on-line. Simultaneously this new Smith predictor doesn't include the prediction model of the controlled plant, thus it doesn't need to know the exact mathematical model of the controlled plant beforehand. It is applicable to some occasions that network delay is random, time-variant or uncertain, larger than one, even tens of sampling periods, and there are some data dropouts in closed loop. Based on CSMA/AMP (CAN bus), the results of the simulation show the validity of the control scheme.