Motion instant center adjustable type prosthetic multiaxial joint

The invention relates to a motion instant center adjustable type prosthetic multiaxial joint and belongs to the technical field of biomedical engineering and rehabilitation assistance. The multiaxial joint comprises a leg connection rod, a rear joint arm, an upper joint body and a front joint arm, wherein every two of the leg connection rod, the rear joint arm, the upper joint body and the front joint arm are hinged to form a quadrilateral structure with a connection rod; the crossed point of the extension lines of the axial lines of the front joint arm and the rear joint arm in a motion plane is a prosthetic motion instant center; the rear joint arm, the upper joint body and the front joint arm are adjustable in length, so that the motion instant centers in different positions can be obtained; and the multiaxial joint is connected with a receiving cavity through the upper joint body and connected with a leg through the leg connection rod. According to the multiaxial joint, other connection rods except for a frame are all enabled to be adjustable in length on the basis of the original multiaxial knee joint, different joint motion instant centers can be obtained by adjusting the rod length, and absolutely stable, cooperatively stable and flexibly controllable prostheses are changed over through centrode transformation.