Robust Performance Assessment of a Simulink-Tuned PID Controller for a DC Motor: A Case Study in Noise Rejection

Abstract

This paper presents a comprehensive simulation-based analysis of a tuned Proportional-Integral-Derivative (PID) controller applied to a Direct Current (DC) motor within the MATLAB/Simulink environment. The primary objective is twofold: First, to establish a baseline performance benchmark by quantifying the transient response characteristics of the closed-loop system under ideal noise-free conditions; and second, to rigorously evaluate the controller's robustness and disturbance rejection capabilities when subjected to stochastic measurement perturbations modeled as Band-Limited White Noise. The PID controller parameters (Kp=8.3463, Ki=36.9358, Kd=0.39908, N=731.767) were derived using the automated PID Tuner tool in Simulink to achieve a desired balance between rapid reference tracking and minimal overshoot. Simulation results for the nominal case reveal a rise time of 0.243 seconds, a settling time of 0.817 seconds and an overshoot of 7.04%, with guaranteed stability margins including a phase margin of 69 degrees at 6.4 rad/s. Upon activation of the Band-Limited White Noise source configured with a noise power of 1×10⁻⁷ and a sample time of 0.001 seconds, the system maintained unconditional closed-loop stability and zero steady-state error albeit with the expected presence of high-frequency ripple on the output signal. The findings conclusively demonstrate that the tuned PID controller provides a robust and industrially viable control solution for DC motor applications, effectively preserving transient performance and stability even in the presence of realistic sensor noise artifacts.