절점주파수 부근에서의 DC모터 주파수 특성

Frequency Response in DC Motor around Corner Frequency

The present study is experiment about the frequency response in DC motor around the corner frequency. Assuming that DC motor keeps 1st system characteristics. The time constant is a reciprocal number of the corner frequency in the 1st system. Using DC motor with encoder circulating the market, I make experimental set to measure the DC motor speed. By applying the unit step voltage to DC motor, the velocity variation of the DC motor is measured through encoder sensor. I quantify the time constant using interpolation in velocity variation data and calculate the corner frequency. To compare the experimental velocity and the theoretical velocity, the eight frequencies(0.2Hz, 0.5Hz, 1.0Hz, 2.5Hz, 3.5Hz, 5.5Hz, 8.5Hz, 13Hz) are selected. PWM control inputs of the above eight frequency apply to DC motor driver and acquire the motor velocity through encoder signal respectively. To evaluate the difference of the motor velocity and the 1st system output, I use linear regression. As a result the correlation coefficient is 0.95572.