Meeting Abstract

 

31-5  Friday, Jan. 4 14:30 – 14:45  The detachment of remora: kinematics, dynamics, and a bio-robotic model WANG, S; LI, L; CHEN, Y; KENALEY, CP; WAINWRIGHT, DK; WOOD, RJ; WEN, L*; Beihang University; Beihang University; Harvard University; Boston College; Harvard University; Harvard University; Beihang University liwen@buaa.edu.cn http://softrobotics.buaa.edu.cn/

Remoras have the extraordinary ability to attach to a wide variety of marine surfaces as well as to detach rapidly. To investigate how remoras detach, we conducted experiments on living remoras (Echeneis naucrates), and further developed and evaluated a bio-robotic remora disc. We captured and analyzed synchronized high-speed videos, measured external normal and shear forces, and the inner disc chamber pressure of living remoras (body length: 28 ±1.0 cm) during the attachment and detachment processes. Results from the high-speed videos show that living remoras can detach within 220 ms, with a maximum detachment angular velocity of 6.4 rad/s. To achieve rapid detachment, remoras fold down the disc lamellae away from the attached surface, and then curl the disc lip upward (away from attached surface) starting from the disc anterior. Using contrast stained µCT of Remora remora, we showed that the muscle around the soft disc lip can trigger/initiate the disc lip’s curling motion. Based on the described kinematic and morphological features, we developed a multi-material bio-robotic disc (whose stiffness spans from 0.5 Mpa to 200 Gpa) that enables both attachment and detachment. Detachment in the bio-robotic disc mimics the motion of a biological lamellae and the disc lip, and the contact has been visualized through the FTIR approach. During detachment, we found that the pulling force of the robot is reduced by over 250 times compared to that of the fully attached state. Repeated underwater attachment and detachment were demonstrated through incorporating the biomimetic disc on an underwater swimming robot. We hope that this study will inform the development of an untethered robotic system for underwater hitchhiking in realistic aquatic environments.