The modeling of cartwheel flexural hinges

Cartwheel hinges, formed by two flexible leaves intersecting at their mid points, have been used in compliant mechanism applications, especially when high precision and large-deflection are required. To analyze their kinematic motion, two pseudo-rigid-body models are proposed: a bar model and a pin-joint model, which are validated by the result of non-linear Finite Element Analysis (FEA). Our data shows that both models are accurate in predicting the load-deflection, rotational precision and stress characteristics of the hinge even for large deflection applications. Though the bar model provides a slightly better result, the pin-joint model is more convenient in analysis and design of compliant mechanisms.