Microtension control for a yarn winding system with an IMC PID controller

In this paper, feedforward compensation and an internal model control (IMC) PID tuning method to maintain the yarn tension within a micro-boundary range are proposed. The proposed method can be used to improve the quality of products in textile industry. We first develop a mathematical model of the AC servo motor and yarn tension system. Based on the results of the mathematical model, an IMC PID controller is designed to control the microtension of the yarn. The proposed IMC-PID controller can be directly calculated from the time constant and time delay. Feedforward control is used to compensate for the linear velocity of the winding roller. To reduce the lateral vibrations of the yarn, we designed an active roller to nip the moving yarn. The active roller compensates for the variation in the diameter of the unwinding roller. The proposed method effectively improves the dynamics performance and the robustness of the system, and is appropriate for industrial application. Experimental instruments, including a tension sensor, an AC servo motor and a motion controller, equipped with a computer, are used to test the proposed method. The simulation and experimental results show the effectiveness of the proposed controller for the yarn microtension control system