Bellows Suction Cup Equipped With Force Sensing Ability by Direct Coating Thin-Film Resistor for Vacuum Type Robotic Hand

This article proposes a novel object handling device for a robot, in which a conventional vacuum suction cup is equipped with a force sensing ability by coating its surface with a conductive thin-film polymer, poly (3, 4-ethylenedioxythiophene) (PEDOT). It can detect the applied force by measuring the resistance change of the coated conductive thin film. The feature of this article is that the suction cup can work, not only as a grasping tool, but also as a force sensor. PEDOT thin film was prepared using the dip-coating method, which can coat thin film directly on a three dimensional surface. We fabricated the sensing suction cup and evaluated its sensing ability by measuring the signal-to-noise ratio, sensitivity, reliability, and frequency response. The resistance changed linearly with respect to the applied force, showing the device's applicability as a force sensor for a vacuum-type robotic hand. Grasping tests for an inclined object, a misaligned object, and an undulated surface were conducted using two or four sensing suction cups attached to the end of the robot. All suction cups showed positive results and the robot successfully picked up the object in each scenario.