Maglev weft knitting needle driving modeling and PID controller design

Abstract

Maglev driving method is a novel needle driving technology for weft knitting machine, which uses the non-contact hybrid magnetic driving method to replace the traditional cam type knitting needle driving method. This method can alleviate the problems of noise, heating and broken knitting needle during the operation of knitting machine. This paper designs a hybrid magnetic levitation needle drive structure. Based on the structure and driving mode, the equivalent magnetic circuit model and the axial mechanical model of the needle are established. The state equation is used to analyze the axial displacement response of the needle under setting voltage. Moreover, the closed-loop controller of the needle drive is optimized to make the needle have stable axial displacement response. A hybrid maglev needle driving experimental device is also designed. The relationship between the axial displacement and the coil driving voltage is calculated by using the analytical method and the numerical finite element method. The results show that the hybrid maglev knitting needle axial drive structure and drive control method can meet the requirements of needle drive height. This study provides a reference for the design of new hybrid magnetic suspension knitting machine.