Genetic algorithm tuning based PID Controller for liquid-level tank system

Abstract

This paper presents a design of PID controller for liquid-level tank system. The controller is tuned online by Genetic Algorithm (GA). The liquid-level tank system has limitations and it is difficult to control optimally using only PID controller as the parameters of the system are changing constantly. For this reason the strategy of online GA tuning is used in this work. Genetic algorithm has been shown to be capable of locating high performance areas in complex domains without experiencing the difficulties associated with high dimensionality or false optima as may occur with gradient decent techniques. By using the reproduction , crossover and mutation to create the new population for other parameters, it can continuously control the liquid – level tank system until the preset iteration number is reached. Finally, the best PID parameters can be obtained using this approach. Simulation results indicate that the performance of the PID controlled system can be significantly improved by tuning with GA method.