ADLIF: a new large-displacement beam-based flexure joint

A flexure joint is an important component in flexure mechanisms. Most of well known flexure joints have always a trade-off among such performances as precision, stiffness, and stroke, which heavily affect the overall performances of flexure mechanisms. In this paper, a new flexure joint, named an anti-symmetric double leaf-type isosceles-trapezoidal flexure joint (ADLIF), is introduced. The joint is constructed by two leaf-type isosceles-trapezoidal flexure (LITF) building blocks in an anti-symmetrical form. In order to investigate such characteristics as precision, stiffness and stroke, two ADLIFs with different structural parameters are compared with a cartwheel hinge. In addition, a simple and accurate pseudo-rigid body (PRB) joint model of the ADLIF is formulated to simplify the parametric model and achieve the structural optimization. The results show that the ADLIF can gain a great improvement in precision as well as maintain other characteristics such as stiffness and ranges of motion similar. Even the ADLIF gets more than 16 times improvement in precision in the case that the rotational angle is less than five degrees (5 degrees). The ADLIF can thus be used for the replacement of the cartwheel joint in some precision application fields.