Quasi-static and Modal Analysis of Bridge-Type Compliant Mechanism with Flexure Hinges

Displacement amplification ratio and input stiffness are significant design characteristics for an ultra-precision positioning flexure-based compliant mechanism. Early and accurate performance prediction models can significantly improve the reliability and availability of product in the field of ultra-precision positioning, but Existing theoretic models cannot predict its characteristics accurately and make it very difficult to error compensation by means of these models. This paper provides a set of uncanonical linear homogeneous equations for calculating a classic bridge-type mechanical amplifier performance, these closed-form equations are established based on the thought of statically indeterminate structure, including Force Method, Maxwell-Mohr Method and deformation compatibility. Subsequently, case studies involving the calculation results compared with FEA, geometric parameters´ influence discussion and modal analysis using FEA simulation are presented. This proposed analytical model is applicable and reliable to the bridge-type micro-displacement amplifier design and verification. Furthermore, the present model can be used in any other over-constrained flexure-based amplifier.