Design and Modeling of a Compact Three-Stage Displacement Amplification Mechanism Based on RBC-Inspired Flexure Hinges

Compliant mechanisms have increasingly sparked great attention in engineering fields. In this paper, a compact three-stage displacement amplification mechanism based on flexure hinges inspired by red blood cells (RBC-inspired flexure hinges) is designed and modeled. The lever-type, Scott-Russell and half of a dual-arm elliptical mechanism combine to construct a compact compliant mechanism that balances long stroke and high frequency. The RBC-inspired flexure hinges provide high rotational precision and uniform stress distribution. Meanwhile, the dual-arm elliptical mechanism has uniform stress distribution, acceptable output stiffness, and nondecreasing response frequency. The modified graphic transfer matrix method (GTMM) is employed to forecast the kinetostatic and dynamic performances, which are confirmed by finite element analysis (FEA). The modified GTMM integrates the modeling concepts of the discrete beam transfer matrix method and graphic transfer matrix method, resulting in unified linear kinetostatics and dynamics that are obtained from the transfer matrix instead of being converted from the dynamic stiffness matrix. The proposed three-stage displacement amplification mechanism gives an insightful viewpoint on designing compliant mechanisms appropriate for high-frequency and large-workspace applications.