Design of static balancing mechanism for face robot

This paper proposes a static balancing mechanism for a face robot that uses the space mapping method. The joints of the face robot are configured using yaw-pitch-pitch-roll rotations. A design method based on the space mapping is adopted and extended to a multiple-degree-of-freedom (multi-dof) unit gravity compensator space. The joint space and gravity compensator space are determined, and the mapping between the two spaces is obtained using analyses of the potential energy in the spaces to determine the number of unit gravity compensators and their locations. The design is conducted using the multi-dof gravity compensator space and suggests that two unit gravity compensators are necessary, with parallel constraints. Dynamic simulations are conducted; the results show that the proposed gravity compensators effectively counterbalance the gravitational force, and the total potential energy is invariant for all poses.