Disturbance Observer Based Current Controller for a Brushed DC Motor Ⅰ

  Current control is essential for torque control. But available current controllers don’t provide the required facilities for torque control. Often they produce a sluggish response. In this paper we propose an embedded system based current
controlling method using the disturbance observer. Dynamic model of the DC motor is analyzed electrically and mechanically. Then the proposed method is analyzed by introducing the concept of disturbance observer. Real Time Operating System (RTOS) is used in the experiment. Results show the response current variation with and without the disturbance observer. Validity of the proposed method is verified by the results.

I. INTRODUCTION
  DC motors are used in wide range of applications ranging from small toys to locomotives [1][2]. Brushed DC motors
have become popular due to its simplicity in control and cost. In most of the applications open loop velocity control is
implemented simply by controlling the voltage [3]. In most of the applications where velocity control is used, simple
feedback control is sufficient for small motors. Fig. 1 shows a simple velocity controller in block form with feedback.