Research On Optimization Design Of Planar Multiple-linkage Dwell Mechanisms

When requiring a high bearing capacity and a fine wear resistance capacity, a planar linkage mechanism is needed. And it is extensively used in light industries such as printing, textile and food industry, and so on. Linkages are made up of links and joints with surface contact, so they possess of many advantages like holding high loads, high anti-wear ability, good lubrication performance and easy to produce. Generally it was very difficult and complicated to design a linkage mechanism and its result was not precise in the past. With the developments of computer techniques and calculation techniques, optimization method is one of main approaches to design linkage. It became an important subject and hot point how to use optimization design to machinery which can exactly reach design demands. Linkage is so widely used in various machines that it is necessary to study mechanical optimization design, which has great theoretical significance and engineering worth.At the beginning, theories about mechanical optimization design are studied and several main methods of optimization design are compared and analyzed. Considering the faults of conventional optimization methods, the theorem of quantum evolutionary algorithm (QEA) is studied and a novel optimization algorithm is introduced. Then Matlab program of simple quantum inspired evolutionary algorithm (SQIEA) is made and applied to Dimensional synthesis path generation of planar mechanism in order to make motion track of the designed mechanism perfectly approach to a given 8 paths. Thus the combination of SQIEA and linkage design is realized. Thirdly, the theory to create a dwell with linkages is researched and then two important transmissions mechanism of high speed warp knitting machine are chosen as research object, which are transmission mechanism of latch and needle core. They are respectively to make the follower realize dwell by using coupler curve and limit position. Kinematics analysis of them is done firstly. Then based on optimization design theory, the mathematical optimization models of them are presented. In the end, dimensional synthesis optimizations for position parameters are carried out and multi-object of mechanical optimization designs of them taking into account dwell and acceleration or angular velocity are performed.Because of using the theory about assur group and graphical analytical method, mathematical optimization models of multiple-linkage dwell mechanism and the analysis approaches presented in this paper have widely adaptive and they can be applied to analyze other type planar linkage.