Numerical simulation and tension regulation of yarn mechanics on warp knitting machines

Abstract

This research aims to solve the problem of large yarn tension fluctuation in different angle regions of one course. The importance of yarn tension regulation is demonstrated by numerical simulation and a yarn tension regulation system is designed. In particular, by combining the motion of the loop forming mechanism, the force on the yarn is simulated and calculated by the finite element method; the knitting accuracy deviation caused by the yarn force acting on the guide needle and knitting needle is also analyzed and simulated. On the basis of theoretical analysis, the hardware and software platform of the tension regulation system are developed, the selection of the tension control device is optimized, the software control module is designed, and the motion curves of quintic polynomial displacement, velocity and acceleration are planned to realize yarn tension regulation. Experiments are conducted under different lapping and speeds. Experimental results show that compared with the traditional let-off control system, the designed tension regulation system can reduce the yarn tension peak by at least 51.7% and the yarn tension fluctuation range by at least 54.9% in one course. The experimental results verify that the designed tension regulation system has excellent control performance for dynamic yarn tension, and thus improves the yarn knittability and knitting accuracy.