Abstract:Depending on the principle of synchronous construction networked control system (NCS), the effect of time-variant, random and uncertain network delay on the synchronization error is analyzed. Then, the blemish and disadvantage of traditional Smith predictor, which is used for synchronous control of the multiple controlled plants, are also analyzed. An improved Smith predictor is proposed to realize multiple Smith predictive compensation for the network delay, controlled plants with pure delay and the controller of synchronization error, eliminating the delay of feedback path from the control system totally. The prediction model does not contain network delay, so it does not have to be estimated or measured. With the synchronous NCS of segment erector for shield based on CAN (controller area network), the simulation comparison between the conventional PID (proportion integral derivative) networked control and the one based on improved Smith predictor is carried out, and the experiments are performed to evaluate the performance of the proposed method. Finally, the results show that the conventional PID networked control and the one based on improved Smith predictor behave with synchronization error of -3~3mm, -1.5~1.5mm respectively. The latter can improve the performance of the synchronous construction networked control system significantly.