A new type of spherical flexure joint based on tetrahedron elements

In this paper we present two new designs of spherical flexure joints, which are the compliant equivalent a traditional ball-and-socket joint. The formed by tetrahedron-shaped elements, each composed three blade flexures with trapezoidal shape, that connected in series without intermediate bodies. This is respect to currently found literature and helps increase range motion. We also planar ( x - y θ z ) joint were derived as special versions designs. these tetrahedron elements have degenerated triangular prisms. For detailed investigation developed representations prism proved four constraint stiffness terms depend solely on properties main flexure. Furthermore, equations for compared finite-element simulations, showing good correspondence element Normalized Mean Absolute Error (NMAE) 1.9%. element, showed only capture qualitative behaviour NMAE 34.9%. Also, an equation optimal width regarding rotational stiffness. • Two joints presented. These high-precision joints. elements. enable large motion adding Design insights provided.