Analysis And Research On Static And Dynamic Characteristics Of Parallel Machine Assembly Considering The Joints

With the rapid development of manufacturing,a variety of parallel equipment is also developing rapidly,it has been a hot spot in the current research to accurately predict the performance of the machine,however,due to the existence of a large number of joints in the machine(fixed joint and the joint movement,etc.),which makes the characteristics of the machine becoming more complex and diverse.According to the data,the static stiffness of machine tool in 30%~50% depends on the stiffness of joints,the dynamic flexibility of over 60% is derived from the joint,damping is more than 90% from the joint,it can be seen that the joint has great influence on the whole machine.In view of the important role of the joint,this paper starts with the static and dynamic characteristics of the typical joint in the parallel machine,and takes two parallel machines,4PRR parallel robot and 2RPU/UPR parallel robot as the research object,the static and dynamic characteristics of the parallel machine are analyzed and studied,the main research content is as follows:Firstly,the static and dynamic characteristics of bolt,bearing and lead screw are analyzed,and the effective simulation method for the static and dynamic simulation analysis is summarized.Secondly,the theoretical analysis of the cantilever beam is carried out in the analysis of the fixed joint,the simulation precision and application situation of different modeling methods are summarized;the characteristics of rolling ball bearing and ball screw are emphatically analyzed,based on the Hertz contact theory,the theoretical formula of the load deformation of the bearing and the lead screw is derived,respectively on the 6206 bearing and the 71807 bearing in the finite element simulation and calculation examples,and on the shafting screw structure and components were analyzed by experiment and simulation,the applicability and effectiveness of the two equivalent simulation methods are summarized.Finally,the structure of 4PRR parallel robot and 2RPU/UPR parallel robot assembly is introduced respectively.The processing methods of the typical joint in the static and dynamic analysis are summarized,and the static and dynamic characteristics of the whole machine are analyzed.The static and dynamic characteristics of 4PRR parallel manipulators are established and compared with the simulation analysis.The important components of 2RPU/UPR parallel robot(frame,branch pole and moving platform)are optimized and analyzed.Important components and the whole machine were optimized before and after the modal contrast analysis and the whole dynamic characteristics of the harmonic response comparative analysis.In this paper,the static and dynamic characteristics of the typical joint in the parallel machine are analyzed and experimentally studied,which provides the basis for the accurate and rapid establishment of the finite element model.