Design of fractional order 2-DOF PI controller for real-time control of heat flow experiment

Abstract

This paper presents a two degree of freedom fractional order PI controller for temperature control of a real-time Heat Flow Experiment (HFE). The introduction of two degrees of freedom and fractional calculus to PI controller enhances its flexibility at the cost of large number of tuning parameters and controller design becomes a combinatorial problem. Controller parameters are therefore optimized by a meta-heuristic algorithm called as water cycle algorithm (WCA) which leads to WCA tuned two degree of freedom fractional order PI (W2FPI) controller. The present work also explores the potential of WCA as an effective controller tuning technique. The convergence analysis of WCA justifies its effectiveness with respect to state-of-the-art optimizers i.e. genetic algorithm, simulated annealing, dragonfly algorithm, flower pollination algorithm, cuckoo search algorithm, particle swarm optimization, differential evolution and artificial bee colony algorithm. Investigation reveals the superiority of W2FPI controller in comparison to its WCA tuned integer order variant W2PI and conventional PI controller. Keyword: 2-DOF FOPI Controller, Heat flow experiment, Water cycle algorithm, Optimization