Structural optimization method towards synthesis of small scale flexure-based mobile grippers

This paper presents a novel synthesis method for the design of micro-scale robotic flexure mechanisms. A structural optimization method, termed the mechanism-based approach, is used to identify the optimal topology and shape of the flexure mechanisms based on their lump stiffness characteristics. Using several different fitness functions, several optimal flexure designs have been synthesized for use in millimeter-scale mobile grippers (μ-grippers). The stiffness characteristics of the optimal μ-grippers are shown to be better than the thin-beam designs developed using human intuition. Two large-scale prototypes are constructed and experiments are conducted to validate the stiffness analysis. The experimental results are within 20% of the analytical expectations. As a proof of concept, at-scale μ-grippers are constructed based on photolithography and replica molding methods, and demonstrated in simple actuation. The optimal μ-grippers can be applicable for cell manipulations in future works.