一种新型并联机床的驱动输入选择

基于螺旋理论，将并联机床全部分支中可作为驱动输入的运动副锁定后，可以得到作用在动平台上的约束螺旋．选出与机构的自由度数目相同的约束螺旋与机构本身固有的结构约束螺旋组成约束矩阵，根据约束矩阵的秩确定输入的合理性．将约束力／力矩矩阵的最小奇异值与最大奇异值之比定义为约束力／力矩各向同性度，并以此为指标对各驱动输入组合的优劣性进行评价．驱动输入选择结果表明，该并联机床存在5 种合理输入，其中以UPS 分支中的5 个P 副为驱动输入是最优组合．

Actuating Input Selection of a Novel Parallel Machine Tool

Based on the screw theory, the constraint screws acting on the moving platform can be got when the pairs, which can be acted as actuating input pairs in all limbs of the parallel machine tool (PMT), are locked. The same amount of constraint screws as the degree-of-freedoms of the mechanism are selected to constitute the constraint matrix with the structure constraint screw inherent in the mechanism. The rationality of input selection can be judged by the rank of the constraint matrix. The constraint force/torque dexterousness is defined as the ratio of minimum singularity value to maximum one of the force/torque constraint matrix, by which the performance of the combinations of actuating inputs are evaluated. The result of actuating input selection shows that there are 5 kinds of reasonable actuating input combinations in 5-UPS/PRPU PMT, and the actuating input combination of the 5 prismatic pairs in UPS limbs is the best one.