A Study on PLL Speed Control System of DC Servo Motor for Mobile Robot Drive

자립형 이동로봇 구동을 위한 직류 서보전동기 PLL 속도제어 시스템에 관한 연구

The speed control associated with dc servo motors for direct-drive applications of mobile robot is considered in this study. Robot is moved by power wheeled steering of two dc servo motors mounted to it. In order to cooperate with micro-computer and to achieve the high-performance operation of dc servo motor, speed control system is composed of a digital Phase Locked Loop and H-type drive circuit. And the motor is driven by Pulse Width Modulations. In controlling PWM, it is modified to compose of H-type drive circuit with feedback diodes and switching transistor and design of control sequence so that it may show linear characteristics. As a result, speed characteristics of motor showed linear features. In order to get data on design of PLL control system, the parameters of 80[W[ motor & robot device is measured by simple software control. The PLL speed control system is schemed and designed by leaner drive circuit and measured parameters. A complete speed control system applied to 80[W] dc servo motor showed good linearity, stability and high response. Also, it is verified that the PLL speed control system has good compatibility as a mobile robot driver.