3UPS-S并联机构单支链驱动奇异分析

并联机构进行单支链驱动时，由于受到其他支链的约束，不能实现全行程范围运动.为了分析并联机构单支链驱动受限的本质原因，采用旋量互易积的方法，计算单支链驱动的轴向速度分量.从计算结果可知，轴向速度为零时，单支链驱动到达边界.并联机构在输入空间发生驱动奇异，同时在工作空间发生位姿奇异，因此并联机构的驱动奇异就是位姿奇异.通过分析输入输出速度关系，并联机构到达输入空间边界.最后给出了并联机构单支链驱动的一般策略. 

Singularity of 3UPS-S parallel mechanism in single limb motion

If only one limb of the parallel mechanism was driven, this limb can't move in full stroke because of the constraints from other limbs. In order to analyze the essential cause of single limb motion limit in parallel mechanism, the method of screw reciprocal product was adopted to calculate the axial velocity component. According to the result, when the axial velocity changes into zero, the single limb motion arrives boundary. The parallel mechanism is in single limb motion singularity from input space. At the same time the parallel mechanism is in configuration singularity from workspace. So the single limb motion singularity is equal to configuration singularity in parallel mechanism. By analyzing the input and output velocity at the moment, the parallel mechanism got to the boundary of input space. Finally the general strategy of single limb motion was given.