Design and tuning of PIλDμ controller for higher order process using PSO-NM

FOPID controller is more vigorous and has better control performance than conventional PID controller because it has two more degree of freedom. There has been an increase in applications of FOPID controller in recent years because of increase in research efforts in fractional calculus. In this paper a method for tuning of parameters of fractional order PID controller for higher order process is proposed by combining the properties of a stochastic (PSO) and a deterministic (NELDER-MEAD) optimization technique, which is minimizing ISE. The results are compared with traditional Ziegler and Nichols type critical gain based tuning rules, Nelder-Mead and PSO based optimisation algorithm for higher order systems. FOPID controller is utilized using FOMCON based toolbox. Two higher order plants are taken for demonstration of better result.