中文摘要：

并联机构的方位特征集与其拓扑结构特征存在密切联系,方位特征集的程序化推导方法对于机构拓扑结构分析与设计具有重要意义。系统论述了拓扑结构多项式、方位关系组及方位特征集等基本概念,采用拓扑结构多项式表达并联机构的支路及运动副排列结构,通过方位关系组描述运动副轴线之间的方位关系。基于并联机构动平台的运动输出特性,提出了运动特征空间的概念,根据运动特征空间的相关性建立了2种消元规则,即串联消元规则和并联消元规则。这两种消元规则在拓扑结构多项式与方位关系组之间建立了一种＂商＂运算关系,并可进行迭代消元,其运算结果即为方位特征集。利用并联机构的字符串描述形式,对部分并联机构的方位特征集进行了基于符号的推导分析,其结果验证了所提出消元规则的有效性。研究成果为面向计算机辅助的并联机构拓扑结构特征分析及类型综合提供了必要的理论与方法基础。

英文摘要：

Position and orientation characteristics（ POC） of parallel mechanism describes the relative motion properties between arbitrary two links of parallel mechanism. POC has close relationship with topological characteristics of parallel mechanism. Whereas,POC of general parallel mechanism cannot be obtained easily sometimes. So it is important for topological structural analysis or design to program the POC calculation. Some important concepts were analyzed systematically such as the topological polynomial expression,the orientation group and POC,etc. The aligning structures of limbs and pairs of parallel mechanism were expressed by the topological polynomial expression. The orientation group provides the orientation relationships shared by axes of all pairs and limbs of parallel mechanism. With the motion characteristics of movable platform of parallel mechanism considered,a conception of motion characteristic space was proposed. Based on the correlation among motion characteristic spaces,two elimination principles were constructed： serial elimination and parallel one. These elimination principles build the quotient relationships between topological polynomial expression and orientation group,supporting for iteration calculations with the POC of parallel mechanism and returned as the result. Based on the string description,POCs of some parallel mechanism were derived with symbolic fashion and theresults validated the proposed method. The results of this paper lay some necessary theory and methodology foundations for the computer aided analysis of topological structural characteristics and prototype synthesis of parallel mechanism.