Evaluations of fuzzy-logic-based self tuning PI controller and fuzzy-scheduled PID controller for DC servomotor

Direct Current (DC) servomotors are widely used in robot manipulator applications. Servomotors use feedback controller to control either the speed or the position or both, and the basic continuous feedback control is PID controller. This paper discusses the modeling and simulation of DC servomotor control built using MATLAB/Simulink, and the analysis of controller performance, namely a fuzzy-scheduled PID controller and a fuzzy-logic-based self tuning PI controller with a variation of scaling factor. The singleton fuzzification is used as a fuzzifier: three membership functions for both input and output of fuzzy logic controller. The center average is used as a defuzzifier. Two control modes are applied in sequential to the plant: speed control, and then position control. Simulation results show that fuzzylogic-based self tuning PI controller has better performance in terms of percent OS and settling time compared to fuzzy-scheduled PID controller for the speed control of DC servomotor. © 2008 IEEE.