Application of Stochastic Fractal Search and Whale Optimization Algorithm in Order Reduction and Control of LTI Systems

Abstract

Various researches on implementing evolutionary techniques in numerous engineering applications using different performance indices as objective functions along with different structure of controllers have become an interesting and active area of research. The present research work deals with the application of two evolutionary techniques named as Stochastic Fractal Search (SFS) and Whale Optimization Algorithm (WOA) in the field of order reduction, speed control of DC motor and AGC of two area interconnected thermal power system. newlineIn theory of control system, it is advisable or compulsory to make a simpler model of complex processes for simulation or for control system s synthesis/ analysis. The present work shows the application of SFS algorithm for order reduction and control of LTI systems. Fractal Search is an algorithm utilizing the concept of fractals. newlineReduced order modelling of LTI systems by SFS algorithm is based on minimization of integral square error (ISE) in between the transient responses of original high order system (HOS) and low order system (LOS) in order to obtain all the unknown parameters of LOS. Step and frequency responses have been compared with other available existing methods. In addition, the transient response s parameters of HOS and LOS and obtained ISE value by SFS have also been compared with existing methods in the literature. It has been observed that SFS algorithm outperforms the existing methods by giving low value of ISE and better transient response s parameters. Bar chart comparison of ISE has also been given to show the superiority of SFS algorithm. newlineThe work also includes tuning the parameters of PID controller for speed control of DC motor by SFS algorithm. The Integral of Time multiplied Absolute Error (ITAE) has been used as an objective/fitness function. newline