Reliability-based optimization design of the latch needle mechanism in double-needle warp knitting machine

Based on the matrix method and clearance vector model, a simple, accurate, efficient and general mechanical reliability analysis method is presented to analyze the reliability of a complex linkage mechanism with structural errors and clearances. The output error variances of the latch needle mechanism in double-needle warp knitting machine are obtained based on this matrix method and verified by Monte-Carlo method. Then, an optimization design method for the latch needle mechanism is presented with the use of genetic algorithm, considering the motion requirement and output errors. The optimized latch needle mechanism can meet the double-dwell motion requirement, and has higher displacement accuracy and reliability under the same structural errors and clearance conditions. This method has practical engineering value in solving the contradiction between high precision loop-forming motion and multi-link accumulative errors, reducing cost, and providing a reference for the optimization design for loop forming mechanism in a warp knitting machine.