Automation of stitch length cams in high speed flat weft knitting machines: Online control system and numerical modeling method

Weft knitting is one of the most common methods of producing fabrics. New automated flat machines have been invented for high producing speed, increasing consumer demands, design ability and upgrading of fabric properties. In these machines most of parts are automated but actual stitch length is not controllable.

In this work, we have attempted to design an intelligent control system to control the stitch length of course and modification of stitch length based on numerical modeling of stitched length and cam degrees relationship. The relation between stitch length cam and actual stitch length has been estimated as linear regression of "Newton-Raphson" method by experiment. The results of practical works show that the designed system can control stitched length with low error coefficient about lower than four percent. This system is useable in all flat and circular knitting machines. The stitch length can be changed during knitting process in both case of stability control and designing various types of fabric by stitch length variations.