A suction end effector with multiple pneumatically driven joints composed of flat tubes and link mechanisms

Focusing on use of flat tubes as pneumatic actuators, we propose a pneumatic drive joint unit in which both sides of a rigid link member are sandwiched between flat tubes. The proposed pneumatic joint unit features both smooth drivability and high load-bearing capacity. For the flat tube used in this study, we independently fabricate a commercially available thermoplastic urethane tube by thermal processing, allowing for use of a highly airtight commercial joint and thereby realizing improved operational reliability and lower cost. We confirm that a 175 N force is generated when the fabricated flat tube is pressurized to 0.3 MPa. We also develop a suction end effector with five pneumatically driven joint units connected in series. The developed suction end effector has six suction pads and open-state dimensions of 456 (W) × 200 (D) × 80 (H) mm with mass 3.15 kg. When each flat tube of the suction end effector is pressurized at 0.4 MPa, an opening and closing motion is possible in about 7 seconds. The developed suction end effector is pneumatically driven, so it can follow object shapes and perform in compliance with external forces. Verifications confirm utility of the newly developed suction end effector, which can hold four types of assumed objects by suction or grasping.