Comparative Realization of 2DoF PID Controllers for Flow Process with Measurement Delay

Abstract

Two Degree-of-Freedom (2DoF) PID control techniques presented in this paper were developed based on optimal control theory and with the Anti-Integral Windup (AIW) scheme. The controllers were implemented for a laboratory flow process setup. First Order Process with Dead Time (FOPDT) models had been identified by step testing. The process responses showed a significant non-minimum phase dynamics exhibited for the specific step inputs applied. The measurement delay was considered as large delay in the fast acting loop. In this work the 2DoF PID AIW control scheme was developed in association with the conventional Smith predictor to rectify the final control element’s delayed actuation. The objective of this work was to compare the realization of 2DoF PID controllers tuned for the flow process on the basis of time domain performances. The control system’s performances were analyzed for its ability to minimize the power consumption associated with the final control element. In this paper, it is shown that the 2DoF PID AIW controller performs better than  PID controller and it is a simple and reliable control technique to implement for a real system.

Keywords: Flow process control, two degree-of-freedom PID controller, anti-integral windup, Smith predictor, large delay system

Cite this Article:

Satheesh Babu R, Shreesha C, Thirunavukkarasu I. Comparative Realization of 2DoF PID Controllers for Flow Process with Measurement Delay. Journal of Control & Instrumentation (JoCI). 2015; 6(1): 1–8p.