Comparison of Performance of PID and LQR Methods in Improving the Stability of DC Motor Control Systems

Abstract

DC motors are one type of motor that is widely used in various engineering and industrial applications due to their ease of use and wide speed regulation capabilities. Series DC motors, as one type of DC motor, have large initial torque characteristics, but often overshoot when starting. In addition, this motorcycle also shows low stability, where the speed can decrease at high torque and increase drastically without load. Therefore, in order to achieve more accurate and stable speed control, an effective control system is required. This study examines the comparison between two control methods, namely PID (Proportional-Integral-Derivative) and LQR (Linear Quadratic Regulator), in regulating the speed of DC series motors. In an experiment conducted using MATLAB software, the speed of the motor was tested on five different variations of speed setpoints. The simulation results show that both controllers produce very small speed errors, but with different performance characteristics. The PID controller provides a faster response time than LQR, although it still shows a considerable overshoot of about 20%. On the other hand, the LQR controller is capable of eliminating overshoot overall. In addition, the analysis of the starting current also showed significant differences, with the PID controller producing a current overshoot of about 460%, while the LQR was only about 188%. This study provides insight into the advantages and disadvantages of each control method in improving the stability and efficiency of DC motor control, which is very important in applications that require high speed and stability. Both of these methods show strong potential to be applied in a variety of motor control systems in engineering and industry, with LQR being the more stable option when it comes to overshoot avoidance.