非过约束五自由度并联机构存在性问题的解析判定

Analytical Identification for Existence of Non-over Constrained 5-DOF Parallel Manipulators

针对非过约束五自由度并联机构是否存在这一机构学公开难题进行了解析判定。分析了构成两种五自由度并联机构所需要的约束的性质和数目,以及它们之间的关系。以螺旋理论为分析手段,得到了非过约束五自由度并联机构存在的解析条件,找到了可以由3条满足该解析条件的运动支链组成的机构。给出了这类机构存在的约束矢量条件以及设计范例。

An analytical confirmation was presented for whether the non--over constrained 5- DOF parallel manipulators were existed,that is still an open diffcult problem in the mechanism field. Firstly,the property,number and linear relationship of constraints for constructing 2 type of 5--DOF parallel manipulators were analyzed. Based on the screw theory,the analytical conditions for existence of such mechanism was obtained. It proves that mechanism can be constructed by 3 limbs. Finally,the conditions of constraint vectors for constructing non--over 5--DOF parallel manipulators are given, and a design example is given to explain the constraint conditions.