A monolithic microgripper with high efficiency and high accuracy for optical fiber assembly

Micrograsping devices and methodologies play an important role in the performance of high precision positioning systems as they contact the objects to be grasped directly. The polarization maintaining optical fiber´s asymmetry structure generated a polarization axial, so rotational alignment is an extremely important issue to be concerned. To fulfill the demand of grasp and rotation in optical fiber´s assembly, a monolithic 2-DOF flexure-based microgripper is proposed in this paper. An asymmetric structure is adopted. The left part accomplishes the function of grasping, while the right part does the rotation job. In the design of the right part, a novel displacement amplify mechanism, the differential amplification mechanism, is employed for its good performance in amplify ratio. Pseudo Rigid Body Model (PRBM) methodology is applied to determine the dimensions of the flexure joints and the links, as well as the stress concentration of the microgripper. To verify the performance and optimize the parameters of the microgripper, finite element analysis is conducted. Then a final version of the microgripper with high performance is proposed.