A Novel Reconfigurable Revolute Joint with Adjustable Stiffness

In this paper, a novel revolute joint of adjustable stiffness with reconfigurability (JASR) is presented. The JASR is designed with zero-length base link four-bar linkage, and allows adjusting its stiffness to achieve soft- and hard-spring behaviour. The new joint has a compact and light-weight structure and can be integrated in robot and transmissions for different applications. In the paper, mathematical models are developed for the JASR, with which influences of design parameters on stiffness performance are analyzed. A prototype of JASR is constructed and preliminary test results demonstrate the compliance properties of the new joint.