中文摘要：

为简化机构自由度计算,基于GOM公式和杆组位移参数求交,通过分析平行约束力的位置关系判断基点转动参数的有效性,给出并证明了转动不受约束的3种情况,为有效解决集合求交运算中的转动参数是否被约束问题,以及机构自由度快速计算和自由度运动性质判别提供了一种简洁实用的方法。以3种典型机构为例,对基点参数有效性判别和机构自由度快速计算进行了验证。

英文摘要：

In order to express DOF calculation as simple as possible,based on the GOM formula and the intersection calculation of displacement parameters of general link group,three cases were presented and proved when the rotation was not as constrained.These cases were proposed by analyzing the relationship of parallel constrain forces to judge the validity of base point parameters.Therefore,the problem of the validity judgement of base point parameters in the calculation of＂rotation intersection＂was solved effectively.And it provides a neat and practical method for the quick determination of the DOF and motion characteristics.Finally several typical examples from the literature were performed to show how to judge the validity of base point parameters and to calculate the DOF with the method mentioned above.