The Design Of The Control System Of Constant Tension In Yarn Winding

Yarn winding and package is an important process in textile industry, the quality of package yarn directly affects the latter process and textile. The tension of yarn is an important parameter in winding process, so the control of winding tension is crucial and necessary. In this process, appropriate and stable tension will make the quality of package yarn much better.This paper, referring to and summarizing the existing tension control system scheme, proposes and designs a tension control system base on MCU as the main controller, tension sensor as the feedback and DC servo motor as the actuator, structure a closed-loop control system, which predigests the system constructure. This paper also analyzes the working principle and the components of the control system in detail and then gets the mathematic model of the existing system. The tension control schemes are discussed with control theory, and the mathematical models of the schemes is established. The conventional PI control algorithm suitable for the closed-loop system is suggested to improve system properties.Because the yarn winding constant tension control system is a time variation system with the characteristics of non-linear, a satisfactory control effect can hardly be attained from tension system designed with conventional control theory. As the Fuzzy control has the characteristics of independence on the precise mathematical model of the controlled object, good robustness and high adaptability, but conventional Fuzzy control has issues of bad steady-state error. Fuzzy-PI control is presented for the closed-loop system, which overcomes the shortcoming of traditional fuzzy control, effective fuzzy control algorithm is derived, using the theory of adapt fuzzy control in big error range and adapt PI control in small error range. Fuzzy-PI control combines the advantages of PI and fuzzy control, Therefore Fuzzy-PI control can highly improve the properties of the system, and verify it by simulation.The tension control system uses ATmegal6 MCU as the controller, designed the peripheral circuit of MCU, signal input circuit, photo-electricity isolating circuit, Key board circuit and so on. Designed and debugged the control software of MCU, and analog-to-digital software and so on.