A comparative study of various Smith predictor configurations for industrial delay processes

Abstract Efficient control of industrial delay processes is a challenging problem in the field of process control. Time delays are generally experienced in industrial processes from distance velocity lags, composition analysis loops, recycle time, mass, and energy transportation time. A high time delay adds a large phase lag to the system, thereby affecting the closed-loop control system stability and thus not easily controlled with PID approach. Smith predictor (SP) is a prominent technique based on process model for processes with high time delay. Unfortunately, the performance of SP deteriorates when the plant model is inaccurate. To overcome the problems related to conventional SP, various modifications have been suggested over the years in terms of structure alterations and controller parameters tuning improvements. This paper focuses on a comparative study of various Smith predictor configurations available in the literature for controlling inverse, integrating, stable and unstable industrial processes with time delay.