Design, analysis and validation of the bridge-type displacement amplification mechanism with circular-axis leaf-type flexure hinges for micro-grasping system

Abstract

For stable and flexible manipulation, realizing parallel grasping and large output stroke simultaneously has become a key issue in the researches on micro-grasping system. The typical solution is to use compliant orthogonal displacement amplification mechanism (such as bridge-type mechanism), in which the flexure hinges are generally axial load-dominated, whereas the deflection of traditional straight-axis flexure hinges is not related to the axial load under small deflection assumption. In this study, a bridge-type mechanism with circular-axis leaf-type (CALT) flexure hinges is designed, analyzed and validated. Through modeling the generalized displacements of CALT flexure hinge, the positive direction of its axis in the bridge-type mechanism is designed. The precise models of load relations for the CALT flexure hinges in the bridge-type DAM are established, and the multi-objective parametric optimization is further given. Small deflection-based static FEA results verify the generalized displacements’ models of CALT flexure hinge as well as the parametric optimization result. Compared with the corresponding bridge-type mechanism with the largest output displacement in the traditional researches, the output displacement of optimal result is improved effectively. For the design validation, the optimal design result is further applied to construct a piezoelectric-driven microgripper, which grasps parallelly and enlarges the output stroke simultaneously.