Study of the efficiency of the control system with smith predictor using a simulator based on controller owen PLC

Estimation of efficiency of a control system with a PID-controller and Smith predictor for plants with time delay is considered. These plants are typical for heat and power engineering. The program loaded in the controller is equipped with a special module of auto-tuning. The module also determines the parameters of the plant model, the transfer function of which is the second-order with the time delay. The research is made on a laboratory workbench equipped with OWEN PLC, one of which was used as the PID-controller with the Smith predictor and auto-tuning, the other was operated as a simulator of the plant with an actuator. The efficiency analysis of the control system is made by means of transient processes comparison, the processes were obtained when the set point signal was changed and when a step disturbance influenced the plant. The results of the efficiency analysis are given for several plants having different time constant ratio and different relative delay time. It is shown that when the predictor is used with the controller having the initial parameters, the quality of the transient processes when the step disturbance influences the object is lower than the quality without the predictor. The quality was estimated by the dynamic deviation and the process time. The recommendations are given, how to change the PID parameters in the system with the predictor in order to make the control system more efficient.