Displacement Analysis of Large-Deflective Elastic Hinge for Positioning Mechanisms.

In order to perform a precise positioning, flexure joints having backlash-free and frictionless are suitable in micro positioning mechanisms. In the case of flexure joints, relative angular displace- ments at the joints are small. Therefore many flexure joints are used to obtain a large output displacement from a small input displacement in the mechanisms, and they are used within the linear elastic region. In this paper, large-deflective elastic hinges are proposed instead of revolute pairs. They are movable connections between links, and can eliminate an input displacement magnification mechanism and a stress concentration problem at joints. As a result, the length of pseudo-links that considered with geometric relation of hinge's deformation is changed. To solve the nonlinear large- deflective elastic hinge problem under a concentrated load and a moment, the large deflection theory, namely, elastica is used. Also, a concept of movable pseudo-revolute pair to analyze a hinge in the kinematic aspect is proposed, and the validity of the concept is confirmed theoretically and experimentally.