Aerial-aquatic robots capable of crossing the air-water boundary and hitchhiking on surfaces

Abstract

Many real-world applications for robots—such as long-term aerial and underwater observation, cross-medium operations, and marine life surveys—require robots with the ability to move between the air-water boundary. Here, we describe an aerial-aquatic hitchhiking robot that is self-contained for flying, swimming, and attaching to surfaces in both air and water and that can seamlessly move between the two. We describe this robot’s redundant, hydrostatically enhanced hitchhiking device, inspired by the morphology of a remora ( Echeneis naucrates ) disc, which works in both air and water. As with the biological remora disc, this device has separate lamellar compartments for redundant sealing, which enables the robot to achieve adhesion and hitchhike with only partial disc attachment. The self-contained, rotor-based aerial-aquatic robot, which has passively morphing propellers that unfold in the air and fold underwater, can cross the air-water boundary in 0.35 second. The robot can perform rapid attachment and detachment on challenging surfaces both in air and under water, including curved, rough, incomplete, and biofouling surfaces, and achieve long-duration adhesion with minimal oscillation. We also show that the robot can attach to and hitchhike on moving surfaces. In field tests, we show that the robot can record video in both media and move objects across the air/water boundary in a mountain stream and the ocean. We envision that this study can pave the way for future robots with autonomous biological detection, monitoring, and tracking capabilities in a wide variety of aerial-aquatic environments.

Advanced Bionic Attachment Equipment Inspired by the Attachment Performance of Aquatic Organisms: A Review

“…Finally, they discovered a new mechanism-redundant attachment mechanism: A suction cup of a remora could attach to complex surfaces and achieve long-term attachment. As a result, a new robot based on redundant attachment that could swim, fly, and hitchhike across media was born [ 22 ]. As shown in Figure 4 d, compared with the previously designed one, the new bionic remora suction cup robot could operate underwater and in air.…”

“…The first and second generations of bionic attachment robots have been developed through the exploration of the attachment mechanism of the remora. The first-generation bionic attachment robot can attach to moving objects to hitchhike underwater while the second generation, which is better, can realize cross-border flight and attachment fixation both underwater and in the air [ 21 , 22 ]. The loadable bidirectional crawling bionic robot that is inspired by rock-climbing fish can achieve free forward and backward movement in the horizontal, vertical, and inverted planes [ 23 ].…”

Experimental verification of seafloor crustal deformation observations by UAV-based GNSS- A

“…The scienti c applications of UAVs are rapidly increasing [24][25][26][27][28]. In marine engineering, data collection using a helicopter-type UAV has been proposed [29,30] and the development of actual ocean observations has begun [31][32][33].…”

Enhanced Adhesion of Synthetic Discs with Micro-Patterned Margins

“…Conventional suckers function using the pressure differential between the inside and outside of the cavity, both in atmospheric and aquatic environments. The main source of adhesion of natural sucker-like adhesion organs is similar to that of conventional suckers [ 1 , 5 , 6 ]; however, micro-/nano-scale structures found in different parts of the organs also play an important role in the system, despite the different types and forms of natural discs [ 7 , 8 , 9 , 10 , 11 , 12 ]. The suction cups covering octopus tentacles have microscale protuberances in the cavity.…”

“…These protuberances cause liquid to flow into the cavity, which creates additional capillary forces to supplement the adhesion force, increasing the adhesion strength of the suction cups [ 11 ]. The adhesive discs on the back of remora consist of several rows of macroscale parallel lamellae, which increase the remora’s resistance to slippage and enhances friction to maintain attachment to a moving host [ 10 , 12 ]. In addition, a typical multiscale combination is the ’fin-ray-papillae’ system, which is found in the clingfish and hillstream loach.…”