无奇异3UPS+1RPU新型并联机构

为消除并联机构奇异性,研究一种约束支链法构成的新型并联机构.通过在3个UPS支链基础上添加1个RPU约束支链构成一种2转动2移动4自由度并联机构,采用矢量法和虚功原理对机构的运动学、静力学进行分析,得到机构的位置逆解、完整雅可比矩阵及静力映射矩阵;利用矩阵原理对雅可比矩阵进行分析,雅可比矩阵的秩反映了机构的奇异情况,推得约束支链对机构产生奇异性的影响结果.提出3UPS+1RPU并联机构消除机构奇异性的条件,进一步推广得到此条件同样适用于由约束支链法构成的其他非对称并联机构.结果表明,该研究方法为并联机构的奇异性消除提供了一种新途径.

Analysis of a novel 3UPS+1RPU parallel mechanism without singularity

A novel parallel mechanism (PM) constructed by constraining brunched chain method was analyzed to eliminate the singularity. The 4 degrees of freedom PM with 2 revolutions and 2 translations was constructed by adding a RPU brunched chain on the three UPS brunched chains. Its kinematics and statics were analyzed by vector and virtual work principle to get inverse kinematics, full Jacobian matrix as well as static mapping matrix. Jacobian matrix order which can affect the singularity about the PM was analyzed by matrix principle, so the singularity effects of the constraining brunched chain would be acquired. The conditions to eliminate the PM's singularity was given at the last, and condition was extended that it was also applicable to all nonsymmetrical parallel mechanisms constructed by adding constraining brunched chain. The research shows that the method is a new way for solving the elimination of the singularity of PM.