Mobility of Overconstrained Parallel Mechanisms
Mobility of Overconstrained Parallel Mechanisms
复制标题
DOI：
10.1115/1.1901708
复制
发表时间：
2006
影响因子：
3.3
通讯作者：
J. Dai;Zhen Huang;H. Lipkin
中科院分区：
文献类型：
--
作者：
J. Dai;Zhen Huang;H. Lipkin
Kutzbach-Grubler移动准则计算一般机构的自由度。然而，该标准可以打破机制与特殊的几何形状，特别是所谓的过约束并联机构的类。问题在于该准则将所有约束都视为主动约束，甚至是冗余约束，这些约束不影响机构的自由度。在本文中，我们揭示了一些螺旋系统的并联机构，探索它们之间的相互关系，并发展了一个原始的理论框架，这些螺旋系统的运动和约束的并联机构，以确定平台约束，机构约束和冗余约束。研究了螺旋系统的物理特性及其相互关系，提出了一种基于运动和约束螺旋系统分解的可动性分析方法。因此，提出了新的版本的移动性准则，以消除冗余的约束，并准确地预测平台的自由度。从文献中的过约束机制的几个例子说明了结果。
The Kutzbach-Grubler mobility criterion calculates the degrees of freedom of a general mechanism. However, the criterion can break down for mechanisms with special geometries, and in particular, the class of so-called overconstrained parallel mechanisms. The problem is that the criterion treats all constraints as active, even redundant constraints, which do not affect the mechanism degrees of freedom. In this paper we reveal a number of screw systems of a parallel mechanism, explore their inter-relationship and develop an original theoretical framework to relate these screw systems to motion and constraints of a parallel mechanism to identify the platform constraints, mechanism constraints and redundant constraints. The screw system characteristics and relationships are investigated for physical properties and a new approach to mobility analysis is proposed based on decompositions of motion and constraint screw systems. New versions of the mobility criterion are thus presented to eliminate the redundant constraints and accurately predict the platform degrees of freedom. Several examples of overconstrained mechanisms from the literature illustrate the results.