A biorobotic adhesive disc for underwater hitchhiking inspired by the remora suckerfish

Abstract

Remoras of the ray-finned fish family Echeneidae have the remarkable ability to attach to diverse marine animals using a highly modified dorsal fin that forms an adhesive disc, which enables hitchhiking on fast-swimming hosts despite high magnitudes of fluid shear. We present the design of a biologically analogous, multimaterial biomimetic remora disc based on detailed morphological and kinematic investigations of the slender sharksucker (Echeneis naucrates). We used multimaterial three-dimensional printing techniques to fabricate the main disc structure whose stiffness spans three orders of magnitude. To incorporate structures that mimic the functionality of the remora lamellae, we fabricated carbon fiber spinules (270 m base diameter) using laser machining techniques and attached them to soft actuator-controlled lamellae. Our biomimetic prototype can attach to different surfaces and generate considerable pull-off force-up to 340 times the weight of the disc prototype. The rigid spinules and soft material overlaying the lamellae engage with the surface when rotated, just like the discs of live remoras. The biomimetic kinematics result in significantly enhanced frictional forces across the disc on substrates of different roughness. Using our prototype, we have designed an underwater robot capable of strong adhesion and hitchhiking on a variety of surfaces (including smooth, rough, and compliant surfaces, as well as shark skin). Our results demonstrate that there is promise for the development of high-performance bioinspired robotic systems that may be used in a number of applications based on an understanding of the adhesive mechanisms used by remoras.

Pneumatically Attachable Flexible Rails for Track-Guided Ultrasound Scanning in Robotic-Assisted Partial Nephrectomy—A Preliminary Design Study

“…In the attempt to replicate one of the most efficient suction mechanisms in nature, researchers worldwide have investigated several designs of vacuum-based suckers for different robotic applications, e.g., [14], where a soft continuum robotic tentacle that replicates the arm muscles of the octopus during a grasp motion is presented, and [15], where a biomimetic replication of an octopus sucker is used for attachment onto both medical and non-medical environments. Not only the octopus but also the remora suckerfish inspired the design of bio-mimetic suction mechanisms like the 3D printed multi-material adhesive disk presented in [16]. The usefulness of bio-inspired suckers in robotics is evident in [17], where the development of an industrial gripper equipped with vacuum suckers is investigated in the context of unstructured manipulation of soft, rigid and semi-rigid objects.…”

An Introduction to Biomimetic Underwater Adhesion System

“…The hardness value of the sucker structure had been crossed three orders of magnitude, from the soft tissue overlay and soft disc lip (1.0Mpa) to the driving arms and rotation axes of the lamellae (2000Mpa). Through statistical comparison of the adsorption capacity of bionic sucker with different roughness, it was concluded that the lip ring had greater adhesion force on the smooth surface, and on the rough surface, the lamellae bars and spinules had greater effect on the adsorption force [15].…”

Soft wall-climbing robots

“…Although soft robots capable of crawling (32)(33)(34)(35), grabbing objects (36,37), camouflaging (38,39), swimming (40)(41)(42), and growing (43) have recently been developed with pneumatic actuators, shape memory alloys, or dielectric-elastomer actuators, soft wallclimbing robots have not yet been achieved. A recent work reported a tethered soft robot based on pneumatic actuators that could crawl inside a vertical tube (44), but it still could not climb flat walls.…”