Optimized fractional order PID controller for non-minimum phase system with time delay

In this paper an optimized fractional order proportional, integral and derivative (FOPID) controller is designed to control the non-minimum phase (NMP) systems with time delay. The NMP system shows the undershoot behavior because of having zeros in the right half plane and the response becomes sluggish as the time delay increases. For improving the performance of the NMP system an optimized FOPID controller is designed. The parameters of FOPID are optimized using Nelder's and Mead (NM) optimization Algorithm. NM-optimization seeks to obtain the best optimal values of the FOPID controller in the region. The parameters are optimized on the basis of minimizing the integral absolute error (IAE) of the system. Simulation results verify that the proposed controller improves the transient performance like rise time, settling time and overshoot of the system.