3-PPP型柔性并联微定位平台的设计与分析

为解决现有空间平动柔性并联微定位平台（CPMS）结构布局不紧凑，且多轴驱动时各运动副的寄生运动相互累加，导致平台耦合误差增大的问题。首先，设计了一种基于柔性薄板的分布柔度式3-PPP型柔性并联微定位平台。其次，通过结构优化减小了平台的体积，并消除了支链中移动副寄生运动的累加现象。然后，基于柔度矩阵法建立了平台的输入刚度理论模型，并采用有限元仿真验证了理论模型的正确性；同时计算了平台的固有频率，并探究了其与柔性薄板尺寸参数之间的关系。最后，将结构优化前后的平台通过有限元仿真进行了对比分析。结果表明:结构优化后平台的体积减小了67%，且平台在单轴和多轴驱动时均具有更优的运动解耦特性和输入输出一致性。 

Design and analysis of a 3-PPP compliant parallel micro-positioning stage

The structure layouts of the existing spatial translational compliant parallel micro-positioning stages are not compact, and the parasitic motion of each kinematic joint accumulates during multi-axis actuation, which leads to the augment of cross-axis coupling error. In order to solve these problems, first, a distributed-compliance 3-PPP spatial translational compliant parallel micro-positioning stage (CPMS) based on compliant sheet was designed. Secondly, the stage volume was reduced, and the parasitic motion accumulation phenomenon of kinematic joints in each limb was eliminated by the way of structure optimization. Then, the theoretical model of input stiffness was deduced through compliance matrix method. The validity of the theoretical model was proved by finite element simulation. Besides, the natural frequency of the CPMS was calculated, and the relationship between natural frequency of the CPMS and size parameters of compliant sheet was explored. Finally, comparative analysis of the CPMS before and after structure optimization was conducted by finite element simulation. The results show that the volume of the CPMS is reduced by 67% after structure optimization, and the CPMS has better kinematic decoupling characteristic and input output consistency in both single-axis and multi-axis actuation.