The Analysis of Singularity for a Variable Structure with 4 Spatial DOFs Parallel Mechanism
-
摘要: 研究了一种变结构并联机构,这类机构的上、下平台通过4条结构相似的支链连接,各支链上均有一移动副,根据输入选取原则,该运动副适合作为驱动副。机构动平台可具备4个空间自由度。连接支链与上、下平台的运动副采用万向节(U副),由于其拓扑结构的多样性,不同构型下动平台可具有多种空间自由度组合形态。考虑机构的实用性,运用螺旋理论并采用增加约束支链的方法,系统的综合了机构的2T2R和3T1R构型。建立了机构的位置关系方程,利用求导法得到了机构的雅克比矩阵,研究了不同构型下机构的奇异位形,并提出了免初始奇异和全局奇异的措施。Abstract: In this paper,a variable structure parallel mechanism that moving and fixed platforms are linked with four limps possessing is studied.It is feasible that prismatic pairs are selected as driver in each limp based on choice principle of input.Through integration analysis,the moving platform should be provided with 4 spatial DOFs.The universal joints are used to connect limps to moving and fixed platforms,whereas moving platform may obtain many forms of spatial DOFs for various topological structures.Considering practicability of this class of mechanism,2T2R and 3T1R configurations are deduced by screw theory and adding limp.The positional equation and the Jacobian maxim are built,and singular position is researched in different configurations.Finally the method of avoiding initial and global singularity is proposed in order to provide a guide for path planning algorithm.
-
Key words:
- parallel mechanism /
- topological structure /
- singularity /
- Jacobian matrix
-
[1] Fichter E F.A stewart platform-based manipulator:general theoryand practical construction[J].International Journal ofRobotics Research,1986,5(2):157～182 [2] 曲义远,黄真.空间六自由度并联机构位置的三维搜索方法[J].机器人,1989,3(5):25～29 [3] Dasgupta B,Mruthyunjaya T S.Singularity-free path planning forthe stewart platform manipulator[J].Mechanism and MachineTheory,1998,33(6):711～725 [4] Huang Z,Chen L H,Li Y W.The singularity principle andproper of stewart parallel manipulator[J].Journal of RoboticSystems,2003,20(4):163～176 [5] 高征,高峰.新型并联机器人的奇异位形分析[J].机械工程学报,2008,44(1):133～138 [6] 伞红军,钟诗胜,王知行.新型2-TPR/2-TPS空间4自由度并联机构[J].机械工程学报,2008,44(11):298～303 [7] 曹永刚,张玉茹.6-RSS型并联机构奇异性分析[J].机械工程学报,2008,44(6):79～87 [8] 杨廷力.机器人机构拓扑结构学[M].机械工业出版社,2003 [9] 韩书葵.少自由度并联机构真实运动特性分析平[D].北京交通大学,2008 [10] Gosselin C M,Angeles J.Singularity analysis of closed-loopkinematic chains[J].IEEE Transactions on Robotics andAutomation,1990,6(3):281～290 -
点击查看大图
计量
- 文章访问数: 150
- HTML全文浏览量: 22
- PDF下载量: 7
- 被引次数: 0
下载:
