Simple internal model control based modified Smith predictor for integrating time delayed processes with real-time verification

Abstract

Internal model control (IMC) tuned simple modified Smith predictor structure for integrating time delayed processes (IPTD) is reported here. Pole position at origin implies its non-self-regulating behaviour. Processes like distillation column, liquid supply to large storage tank, superheated steam flow to turbine etc. are usually found IPTD processes. Reported modified Smith predictor (MSP) design with multiple controllers is adequate to exhibit anticipated closed loop performance for IPTD processes. Tuning complexity of the reported multi-controller based structure is mitigated by the sole tuning parameter (closed loop time constant) obtained from IMC design. Proposed scheme shows considerable performance improvement during set point tracing by zero overshoot. Additionally, smooth as well as reasonably fast load recovery is ensured. Eminence of the reported scheme is established in terms of performance indices along with stability margins in assessment through recently reported modified Smith predictor techniques. Real-time evaluation of the proposed design is demonstrated on an indigenous set up of level control loop considered as IPTD process.