Research and experimentation on constant warp tension control strategy in the weaving of corner-linked looms

In the weaving process of the corner-linked loom, the stability of yarn tension has a significant effect on the quality of the fabric and production efficiency. Focusing on the beam installation structure of the let-off system, the special weaving process of 30-layer corner-linked fabric, and the characteristics of the let-off motion, in this paper we analyze the main factors affecting the warp yarn tension of the corner-linked loom and two control modes for constant warp yarn tension. We demonstrate the theoretical basis of the position mode, presenting parameter derivation calculations. We propose that the direct control method can be used to control the let-off amount per weft, and that the beam diameter estimation method can be used to ensure sufficient let-off amount. The principle of the integral separation proportional–integral–differential (PID) control algorithm and the tension control transfer function model are elaborated, with comparative simulation analyses. Finally, the software and hardware design of the actual warp yarn system and experimental test data analysis are presented. Both simulation and physical experiment results indicate that, in the continuous weaving process, frequent tension fluctuations can be detected by the tension pendulum rod and angle sensor. The combined PID control algorithm can significantly improve the control accuracy and stability of warp yarn tension. The experimental data curve shows that, under step disturbances, the fluctuation amplitude of the tension pendulum rod remains within ±1°, with no overshoot, fully meeting the special weaving requirements of the corner-linked loom.