A fractional order parallel control structure tuned with meta-heuristic optimization algorithms for enhanced robustness

Abstract

This paper studies an improved fractional order parallel control structure (FOPCS) for enhancing the robustness in anindustrial control loop having a first order process with dead time along with its tuning aspects. Since inclusion of fractionalorder calculus also increase the number of parameters to be determined for a particular control loops, tuning becomes anessential task. Four different tuning methods are considered to optimize the gains of parallel control structure (PCS) andFOPCS. Integral of time weighted absolute error for servo and regulatory problems along with overshoot value have beenconsidered for performance evaluation. Extensive simulation studies including change in setpoint and mismatch in process-model parameters have been carried out. On the basis of these studies, it was observed that FOPCS tuned by backtrackingsearch algorithm, outperformed all other controllers in terms of considered performance measures