Optimal fractional order PID controller design using Ant Lion Optimizer

This paper uses a nature inspired metaheuristic algorithm based on the behavior of ant lions named as Ant Lion Optimization (ALO) to design the fractional order PID controller (FOPID) for controlling first order and higher order systems. The ALO is used to optimize the parameters of the FOPID controllers. This algorithm is based upon the hunting behavior of ant lions which is described by five important phases of hunting the ants: random walk, building trap, entrapments of ants in traps, sliding ants towards the antlion, catching the prey and rebuild the trap. ALO algorithm based fractional order PID controller is proposed for delay system and also for higher order system. To obtain the optimal computation, different performance indices such as IAE (Integral Absolute Error), ISE (Integral Squared Error), ITAE (Integral Time Absolute Error), ITSE (Integral Time Squared Error) are considered for the optimization. As the delay system exhibits non-minimum phase characteristic, to improve gain and phase margin, the ALO based fractional order PID is optimally designed by considering different objective functions such as IAE, ISE, ITAE and ITSE. All the simulations are carried out in Simulink/Matlab environment. The proposed method has superiority value in terms of transient and frequency responses as compared with other methods, which has been demonstrated by illustrative examples.