Optimization And Dynamic Simulation Of Spatial Four-bar Linkage Weft Insertion Mechanism

Weft inserting mechanism is one of the most important parts of weaving machine. The performance of weft insertion systems will directly influence the loom class and weaving quality. However, there are still some big gaps on design and manufacture of gripper loom compared with the foreign advanced technology, especially in the core parts such as weft insertion mechanism. So the comprehensive research of various performance of weft insertion appears particularly important.This article uses the method of theoretical analysis and virtual prototype test to analysis and optimization the characteristics of kinematics and dynamics of space four bar linkage mechanism, which can be included as follows:1) Founding mathematical models of every parts of the mechanism by analytical, emulated and obtained kinematics curve through MATLAB programming. Discussed influence of movement law caused by the length change of connecting rod and jointed arm, rotate speed and the length of crank is also studied. Crank's adjustable scope is calculated. Obtain the conclusion that it is feasible to satisfy rapier's moving requirement by adjusting the length of crank.2) Multianalysis has been made between every parameter of four-bar linkage weft insertion mechanism, which tells the effect of them in adjusting and design. Optimizable parameters have been found. And an appropriate optimization objective function of gripper head acceleration curve has been established. It's also made the optimization by genetic algorithm. An auxiliary analysis software has compiled by MATLAB, which achieved good optimized result.3) Established dynamics mathematic models of every parts of the mechanism by the method of vector mechanics and d'alembert's principle.3D model has been set up by Pro/E. The correctness of theoretical model has been checked by ADAMS.4) Analyzed the stress state of pairs connected with rack. Some exploratory research about the complete balance of shocking force has been made. By compare with the shocking force of the very pairs, some balance index has been put forward. The exploratory studies have been carried out by changing the center of mass's position of related parts. Some corresponding conclusions are achieved as follows:It is considerable to move the center of mass of cross axis to the positive direction of x axle and z axle. For sector gear, it's better to maintain the status, or considerable to move the barycenter of it to the positive direction of x axle or the negative direction of z axle when it is necessary. When it comes to rapier wheel, it's better to keep the centroid position in the rotation center.