The Motion Accuracy And Reliability Optimization Design Of The Loop-forming Mechanism Of RS5/1-EL Warp Knitting Machine

Warp knitting is one of the important methods for producing textile.It has many advantages such as high efficiency,product variety,product fancy flexible structure,high added value and wide application range.It is an important raw material of high-end clothing,textile fabrics and basic materials of high technology product.Instead of cam mechanism,the crank connecting-bar mechanism has been the transmission mechanism in the modern high speed warp knitting machine.The design technology of crank transmission of domestic high speed warp knitting machine is low and the crank mechanism manufacture and assembly accuracy is not high.The disparities with the requirements of high speed and high precision of the looping mechanism are wide.The cost will increase if improving the manufacturing and assembly precision.This paper focuses on the reliability optimization of the slot needle mechanism and tongue mechanism of RS5/1-EL warp knitting machine.Not to improve the manufacturing accuracy of each rod,and selects the suitable tolerance of the hinged joints under the condition of meeting the predetermined reliability.The factors that affecting the kinematic accuracy of the planar linkage mechanism was analyzed,and then introduced the vector equation method to establish the kinematics model,considering the length errors and clearance of hinged joints,the effective length model is established for the different rod and took them into the kinematics equation.The kinematics accuracy reliability model of the planar linkage mechanism has been exported by Taylor series expansion.According to the reliability theory to establish calculation equation of the mechanism reliability.According to the mechanism diagram of slot needle mechanism and tongue mechanism,the kinematics model of each mechanism has been established.Using the multi-body dynamics software ADAMS established the models and simulated and verified the kinematics model is correct.Considering the length error and clearance of hinged joints to established the reliability model of mechanism.Using Matlab to calculated the point reliability of each mechanism and draw the diagram in every 5 degrees,.Selected H/f as the initial tolerance of kinematic pairs gaps.Minimize the sum of clearances radius as the objective function under the condition of meeting the predetermined reliability.Established the reliability optimization model for slot needle mechanism and tongue mechanism.Using optimization function fmincon of Matlab toolbox to select the suitable tolerance.The results are substituted into the reliability model and the correctness of the optimization results is verified.