Comparative Study of PID and Fuzzy Logic Controllers for DC Motor Speed Control

Abstract

Direct-current (DC) motors remain important in variable-speed drives because of their simple electromagnetic structure, high starting torque, and convenient armature-voltage control. Their speed regulation, however, is affected by load-torque disturbances, parameter variation, actuator saturation, and the trade-off between rapid response and overshoot. This paper presents a comparative simulation study of a conventional proportional-integral-derivative (PID) controller and a Mamdani-type fuzzy logic controller (FLC) for closed-loop DC motor speed control. A common armature-controlled motor model is used so that the two strategies are evaluated under identical electrical, mechanical, reference-speed, and disturbance conditions. The PID gains are selected to obtain a fast stable response, whereas the FLC uses speed error and change of error as linguistic inputs with seven membership levels. A 60 rad/s reference step and a 0.15 N.m load-torque step at 3 s are applied. Performance is assessed using rise time, 2% settling time, percentage overshoot, steady-state error, maximum disturbance deviation, recovery time, integral absolute error, and root-mean-square error. The simulation shows that PID produces the faster initial rise, while fuzzy control reduces overshoot, shortens settling time, virtually removes pre-disturbance steady-state error, and limits the speed dip after the load change. The results support fuzzy logic as an effective alternative when robustness and low transient deviation are prioritized, while PID remains attractive when simplicity, analytical tuning, and rapid initial acceleration are the principal requirements.