Structure synthesis of a class of 3-DOF rotational parallel manipulators

The theory of reciprocal screws is used for the enumeration of the feasible limb structures of a class of 3-degree-of-freedom (DOF) rotational parallel manipulators. Geometric conditions for the moving platform to possess finite spherical motion are described. A table of feasible limbs that can be used for the construction of 3-DOF rotational parallel manipulators is developed.