Spread-Band: A Smart Machine Element Enables Compact Parallel Robot Design

This paper presents a planar parallel robot, built of spread-band elements. The robot has a workspace that exceeds its original size by far. The mass of the mechanical structure is extremely low, allowing accelerations up to 120 m/s². A spread-band element consists of a roll with flanges and a cambered metal tape. The arch form of the cambered band allows the transmission of tensile and compressive forces and of one moment. The flange of the roll changes the orientation of the bending radius axis by 90°. Nevertheless the combination of roll and cambered band retains the bands flexural rigidity against a moment around an axis perpendicular to the longitudinal axis of the cambered band and the axis of the roll. This leads to the possibility of transforming rotation into translation and vice versa using spread-band elements. The combination of several spread-band elements performed in the presented robot results in a rigid mechanical system.