SELF-TUNING OF AN INTERVAL TYPE-2 FUZZY PID CONTROLLER FOR A HEAT EXCHANGER SYSTEM

A novel technique is investigated for PID controller adaptation in order to control the temperature of a liquid-phase reactor tank by using a heat exchanger system. As for nonlinearity, time delay problems and model uncertainties introduced by the heat exchanger, an interval type-2 fuzzy system (IT2FS) is implemented to enhance and improve the total control performance. Moreover, the fuzzy inference rules which enable the adaptive adjustment of PID parameters are established based on error and error variations. Target tracking, oscillation control and error evaluation for the proposed controller are compared with previously performed control strategies on the mentioned heat exchanger system. The results show that the adaptive technique for PID gain based on IT2FS has lower error and strengthened capacity for external oscillation control and also an acceptable tracking capability.