Abstract: For the shortcomings of the yarn-guiding system electronic controlled, a new yarn-guiding program was proposed in this paper based on the servo control technology and crank-link mechanism of machinery. A mathematical model of the motor motion is established by analyzing the principle of motion of crank-link mechanism, so as to control the servo motor makes variable motion and realize the yarn-guiding alternate motion which comply with process requirement finally Combining the requirements of anti-overlapping, hard-edge and flange prevention in process of yarn-guiding. Based on PLC, the system runs fast, adaptable,has a simple mechanical structure and lower cost, could real-time monitor the rotation angle of motor and change the motor speed step-by-step to ensure the guide bar move steadily. Now this system has been brought into use and proved to be effective in yarn-guiding.

Key words: yarn-guiding system, crank-link mechanism, servo control, to-and-fro guiding yarn