Bifurcated configurations and their variations of an 8-bar linkage derived from an 8-kaleidocycle

The paper presents an eight-bar linkage derived from a rotatable kaleidocycle, a hinged ring of eight regular tetrahedra with revolute joint axes along common edges. A thorough kinematics study of this eight-bar linkage is conducted with screw system approach and the kinematics closure equation is derived in a simplified way. The bifurcated motion of this two-degree-of-freedom linkage is explored in the joint space for the first time. Based on the sagittal planes of the joint space, the bifurcated sub-motions of a special line and plane symmetric Bricard linkage are analyzed.