The invention relates to the technical field of robots, and particularly discloses a bionic humanoid mechanical arm which comprises a
shoulder joint module, a big arm module, an
elbow joint module, a small arm module and a
wrist joint module which are connected in sequence. The
wrist joint module realizes two-degree-of-freedom flexible movement through a regular
octahedron tensegrity structure, and the rotation centers of the
wrist joint module naturally intersect at one point and are connected with the rolling shaft in series to form three-degree-of-freedom concurrent rotation; the length-adjustable supporting rod in the flexible structure changes the joint rigidity in real time and dynamically adapts to the load change so as to enhance the man-
machine interaction safety; an
elbow joint adopts a virtual
pitch circle rolling mechanism, all joint-crossing driving
rope paths are forced to remain unchanged, and multi-joint motion
coupling is eliminated from the mechanical intrinsic level; a driving motor and a
rope wheel
system are arranged on the large arm module in a centralized mode, the
rope tensioning state is continuously optimized in cooperation with a
ratchet wheel type self-locking tension mechanism, and the
tail end
inertia is reduced under the condition that an
elbow and wrist joint motor is completely removed.