A Comparison Study on Motion/Force Transmissibility of Two Typical 3-DOF Parallel Manipulators: The Sprint Z3 and A3 Tool Heads

This paper presents a comparison study of two important three-degree-of-freedom (DOF) parallel manipulators, the Sprint Z3 head and the A3 head, both commonly used in industry. As an initial step, the inverse kinematics are derived and an analysis of two classes of limbs is carried out via screw theory. For comparison, three transmission indices are then defined to describe their motion/force transmission performance. Based on the same main parameters, the compared results reveal some distinct characteristics in addition to the similarities between the two parallel manipulators. To a certain extent, the A3 head outperforms the common Sprint Z3 head, providing a new and satisfactory option for a machine tool head in industry.