Harmony search algorithm and Lyapunov theory based hybrid adaptive fuzzy controller for temperature control of air heater system with transport-delay

Hybrid stable adaptive fuzzy controllers based on the Lyapunov theory and HS algorithm are implemented.Real-life controls of the temperature of an air heater process at different cross sections of air flow duct are implemented.Heat transfer dynamics of the process in the presence of fixed and randomly variable disturbances are tested.The same controllers designed for "no transportation delay" case are also utilized to control the temperature with the incorporation of transportation delay in the process. The present paper proposes systematic designs of stable adaptive fuzzy logic controllers (AFLCs), employing hybridizations of Lyapunov strategy based approach (LSBA) and a contemporary stochastic optimization technique, for controlling the temperature of a thermal process in an air-heater system with transport-delay and in the presence of disturbances. Harmony search (HS) algorithm has been considered here as a candidate stochastic optimization technique utilized in conjunction with the Lyapunov theory to develop the hybrid models in this work. The objective of this work is to design stable adaptive fuzzy controllers which can provide high degree of automation, guarantee asymptotic stability and also achieve satisfactory transient performance by simultaneous adaptations of both the fuzzy controller structure and its free parameters. The results obtained from real-life experiments aptly demonstrate the usefulness of the proposed approach.