IG 42-GM DC MOTOR SYSTEM ANALYSIS USING LQR AND LQT METHODS

Abstract

DC motors are extensively employed across diverse industrial applications due to their versatility in both fixed and variable-speed electric drives spanning wide power ranges. This study investigates the transient response characteristics of a separately excited DC motor speed control system using the Linear Quadratic Regulator (LQR) and Linear Quadratic Tracking (LQT) methods, with LQT
parameters optimized via a Genetic Algorithm (GA). Three motors of distinct power ratings were comparatively evaluated based on transient performance specifications, including settling time, overshoot, and steady-state error. MATLAB/Simulink simulations demonstrate that the LQR-based controller significantly enhances speed regulation quality, particularly in low-power motor
applications, achieving minimized speed deviation and improved dynamic response. Furthermore, the improved first- and second-order speed regulators exhibit superior disturbance rejection and faster transient recovery compared to conventional control approaches. These findings confirm the effectiveness and practical feasibility of integrating LQR and GA-optimized LQT strategies for
robust, cost-efficient DC motor speed control in variable power-rating systems.