Compact modular variable rigidity joint

The invention relates to a compact modular variable rigidity joint which comprises a joint housing, a main driving module, an elastic module and a rigidity adjusting module. The elastic module comprises a variable rigidity pedestal, a linear spring module and two lever assemblies; the rigidity adjusting module is driven by an output end of the main driving module to rotate; the two lever assemblies that are arranged in axial symmetry are rotatably arranged on the variable rigidity pedestal, each lever assembly is provided with a chute, and the linear spring module is slidably arranged on the variable rigidity pedestal; the rigidity adjusting module comprises a rigidity adjusting driver, a bevel gear pair, a cam disc base, a cam disc, a slide block and a first cam bearing follower; the rigidity adjusting driver is mounted on the joint housing, the cam disc base is rotatably arranged in the joint housing, two slide blocks are slidably arranged in the joint housing, and the first cam bearing followers are mounte