Principles of microscale flexure hinge design for enhanced endurance

Articulation based on flexure hinges is increasingly popular in microrobotics because of the absence of Coulomb friction, ease of manufacturability, fluid motion, durability, and large angular ranges. However, the inherent flexibility of these hinges makes modeling very complex and specific to the particular engineering applications for which they were developed. In this paper we describe the development and testing of a simplified, versatile method for modeling the stress on a flexure hinge under multi-axis loads in order to maximize hinge lifespan. We also discuss other stress concentration reducing features and design rules that can be applied to more general flexure hinge designs to further extend hinge lifespan.