Parabolic and hyperbolic flexure hinges: flexibility, motion precision and stress characterization based on compliance closed-form equations

The parabolic and hyperbolic flexure hinges are introduced as new rotation joints to be utilized in two-dimensional monolithic mechanisms. Closed-form equations are formulated for compliances to characterize both the active rotation and all other in- and out-of-plane parasitic motions. The stress levels are also evaluated in terms of compliances. Checked against finite element analysis and experimental measurement data, the model predictions are within 8% error margins. Further simulation is performed to compare geometrically-equivalent parabolic and hyperbolic flexure hinges. The results indicate that the parabolic flexures are more rotation-compliant and induce less stress, while the hyperbolic flexures are less sensitive to parasitic effects. (C) 2002 Elsevier Science Inc. All rights reserved.