Stiffness Analysis of Spherical Parallel Mechanism U_(P+R) with 2-DOF  

作　　者：Yu-Lin Zhou Long Yang Bo Li Da-Xing Zeng Feng Gao 

机构地区：[1]School of Mechanical Engineering,Yanshan University [2]XCMG Xuzhou Truck-Mounted Crane Co.,Ltd. [3]State Key Laboratory of Mechanical System and Vibration,Shanghai Jiaotong University

出　　处：《Journal of Harbin Institute of Technology(New Series)》2013年第4期41-47,共7页哈尔滨工业大学学报（英文版）

基　　金：Sponsored by the National Natural Science Foundation of China(Grant No.51275443 and 51005195);Key Project of Chinese Ministry of Education(Grant No.212012);Research Fund for the Doctoral Program of Higher Education of China(Grant No.20111333120004);Natural Science Foundationof Hebei Province(Grant No.E2012203034)

摘　　要：As one of the typical less-mobility parallel mechanisms, the spherical parallel mechanism Up.s with two degrees of freedom （2-DOF） possess high order overconstraints, and the calculation of its stiffness is partly different with general parallel mechanisms owing to the bars in each branch are assumed to be arc-shaped. By means of small deformation superposition principle, the relationship between the angle displacement and line displacement of moving platform and the forces acted on the branches were derived out. Based on the results of static analysis, the relationship between the applied force, the line displacement and the angle displacement of the mechanism was set up. And then the stiffness matrix was obtained. The six principal stiffness of the mechanism and the corresponding directions were achieved by the orthogonal transformation. The numerical calculation was performed and the results showed that the principal stiffness and directions are varied with the pose-position of the mechanism, and the principal stiffness is gradually enlarged when it is far away from the anigin. In addition, the torsion stiffness is much greater and the line deformation stiffness is smaller, the difference between the two parts is huge. The research content of this paper supplies the theoretical foundation for the further engineering design and application of the spherical parallel mechanism.As one of the typical less-mobility parallel mechanisms,the spherical parallel mechanism U_(P + R) with two degrees of freedom(2-DOF)possess high order overconstraints,and the calculation of its stiffness is partly different with general parallel mechanisms owing to the bars in each branch are assumed to be arc-shaped.By means of small deformation superposition principle,the relationship between the angle displacement and line displacement of moving platform and the forces acted on the branches were derived out.Based on the results of static analysis,the relationship between the applied force,the line displacement and the angle displacement of the mechanism was set up.And then the stiffness matrix was obtained.The six principal stiffness of the mechanism and the corresponding directions were achieved by the orthogonal transformation.The numerical calculation was performed and the results showed that the principal stiffness and directions are varied with the pose-position of the mechanism,and the principal stiffness is gradually enlarged when it is far away from the origin.In addition,the torsion stiffness is much greater and the line deformation stiffness is smaller,the difference between the two parts is huge.The research content of this paper supplies the theoretical foundation for the further engineering design and application of the spherical parallel mechanism.

关 键 词：spherical parallel mechanism static stiffness orthogonal transformation line displacement ANGLE 

分 类 号：TP24[自动化与计算机技术—检测技术与自动化装置]