Research On The Pattern Beam Positive Let-off System Of Multi-bar Warp Knitting Machine

The number of beams of multi-bar warp knitting machine is more and more, and the pattern process is complicated and changeable. The let-off system of patternbeam is the negative type let-off, the warp tension fluctuates greatly and affects the quality of multi-bar products. Combining the characteristics of the pattern process, the electronic let-off system is developed and applied to the multi-bar warp knitting machine, and the performance of the system is tested and studied.The development of electronic let-off system is analyzed, and the research status of electronic let-off system at home and abroad is analyzed, and the gap between the application of international let-off system and abroad is pointed out. Few companies in China apply the electronic let-off system to patternbeams of the multi-bar warp knitting machine, rely on manual adjustment of negative let-off is time-consuming.To study the patternbeam to send off the positive system is imperative.Then, the paper analyzes the technological requirements of the electronic let-off system of the multi-bar warp knitting machine, introduces the components and control principles of the electronic let-off system of the patternbeam, and selects the various components of the system. The control module adopts the DSP controller and FPGA electronic gear algorithm design, realizes the real-time follow-up when the warp beam is sent by the constant send-off amount and the stable yarn-feeding and multi-speed let-off.Then, the control algorithm is designed for the patternbeam let-off system. Because the number of the beams is large and the warp amount of each course will change, the system should first estimate the let-off quantity of the process organization. The fuzzy-neural-PID control algorithm can be used to realize the real-time sending.At last, the performance test and research of the multi-bar warp knitting machine electronic let-off system are carried out, and the control accuracy, sending response and smoothness of the system are tested. The experimental results show that the error rate of the let-off control is less than 0.8% and the accuracy is up to the requirement. Collecting the speed of the beam to send by the motor speed and the command speed curve, while the process of multi-speed cross-cutting process does not exceed a row of spindle weaving time. Using the LMS four-channel vibration test analyzer to collect the positive and negative warp yarn tension fluctuation curve, we found that the warp tension of the electronic let-off system is stable. After the warp tension fluctuation curve is processed in the angle domain, the warp yarn tension of the electronic let-off system is more consistent with the change of the yarn with the angle of the spindle in the forming process. It is concluded that the accuracy, responsiveness and smoothness of the multi-bar warp knitting machine are in accordance with the technological requirement.In short, the subject is based on the characteristics of warp-knitted laid in stitch to develop electronic let-off patternbeam system, to send real-time to achieve real, and good control accuracy, for improving the quality of multi-bar products of great significance for China and the development of patternbeam warp machine made a step.