Atmega88 마이크로컨트롤러를 이용한 모터 엔코더 신호 검출 기법

Detection Method of Motor Encoder Signal Using Atmega88 Microcontroller

Motor rotation speed is measured by a period of encoder signal. The traditional method detects the period of encoder pulse using input capture interrupt function in Atmega88 microcontroller. It is difficult to control two motors because the microcontroller has only one terminal ICP to input the encoder pulse. Therefore the new method is proposed to get two encoder signals. It is to use INT0 or INT1 terminals to detect the period of encoder pulse. In order to test of validity of the new method, experiment device was introduced to measure the square waveform from function generator using both methods. Experiment was repeated with frequency set at 50[Hz], 100[Hz], 200[Hz], 500[Hz], and 700[Hz], respectively. When the measured data were analyzed and compared between each method, a proportional factor is 0.9997 in the traditional method; 1.00023 in the new method. The standard deviation of error was under 0.0001. The present study confirmed through these experiment that the encoder pulse detection performance using external interrupt is similar to the encoder pulse detection performance using input capture interrupt.