Design of Large-Displacement Compliant Joints

This paper investigates the drawbacks of typical flexure connectors and presents several new designs for highly effective, kinematically well-behaved compliant joints. A revolute and a translational compliant joint are proposed, both of which offer great improvements over existing flexures in the qualities of (1) a large range of motion, (2) minimal “axis drift,” (3) increased off-axis stiffness, and (4) a reduced stress-concentrations. Analytic stiffness equations are developed for each joint and parametric computer models are used to verify their superior stiffness properties. A catalog of design charts based on the parametric models is also presented, allowing for rapid sizing of the joints for custom performance. A joint range of motion has been calculated with finite element analysis, including stress concentration effects.