Simulation and Optimization of a PID Speed Control System for a DC Motor Based on Falstad Simulation and GNU Octave

Abstract

DC motors are widely used in electromechanical drive systems. However, traditional open-loop speed control systems suffer from slow response, large steady-state errors, and poor stability. This paper studies a separately excited DC motor speed control system. This study builds a PID speed control system on the Falstad Simulation platform and establishes a DC motor mathematical model in GNU Octave for transfer function derivation, simulation analysis, and PID parameter tuning. A single closed-loop PID control system is constructed, and the controller parameters are tuned and optimized to improve both the dynamic and steady-state performance of the system. Simulation results show that, compared with open-loop control and conventional PID control, the optimized PID controller significantly reduces the overshoot, shortens the settling time, and nearly eliminates the steady-state error. Specifically, the overshoot is reduced from 18.7% to 3.2%, the settling time is shortened from 1.25 s to 0.38 s, and the steady-state error is approximately zero. Moreover, the system can rapidly recover to a stable operating state after external disturbances, demonstrating excellent dynamic performance and strong disturbance rejection capability. The results verify the effectiveness of the PID control strategy and parameter optimization method for DC motor speed control systems, providing a reliable simulation basis and theoretical reference for electromechanical control system design.