A Comparative Analysis on Application of PI and LQR Based Control for Speed Tracking of a DC Motor

DC motors have found extensive industrial usage due to their wide range of speed control and excellent speed torque characteristics. The simplest speed control technique for dc motor is the proportional integral (PI) control due to its ease of implementation since all the control variables are dc quantities. Improved performance can be achieved by using other control techniques like deadbeat control, fuzzy logic control, model predictive control and state feedback control. The optimal control approach of state feedback is Linear Quadratic Regulator (LQR) control which has been proven to achieve better control action compared to classical control approaches. This paper emphasizes on the mathematical approach to design the LQR controller for speed control of a DC motor by converting the reference tracking problem into a regulator problem. The controller has been designed in the Simulink environment of MATLAB and the performance of the designed controller is compared to that of a PI based controller.