2021/11/18 by Dror Kobo, Bat‐El Pinchasik, Kobo, Dror +1
Engineering · Physics and Astronomy · #Biomimetic flight and propulsion mechanisms #Electrohydrodynamics and Fluid Dynamics #FOS: Computer and information sciences #Micro and Nano Robotics #Modular Robots and Swarm Intelligence #Robotics (cs.RO) #Underwater Vehicles and Communication Systems
paper · pdf · doi:10.48550/arxiv.2111.09648
openalex publication_date 2021/11/18 · openalex created_date 2022/10/27 · openalex updated_date 2026/07/28
The backswimmer fly is an aquatic insect, capable of regulating its buoyancy\nunderwater. Its abdomen is covered with hemoglobin cells, used to bind and\nrelease oxygen, reversibly. Upon entering water, the fly entraps an air bubble\nin a superhydrophobic hairy structure on its abdomen for respiration. This\nbubble, however, can change its volume through regulated oxygen flow from the\nabdominal hemoglobin cells. In this way, it can reach neutral buoyancy without\nfurther energy consumption. In this study, we develop a small, centimeter\nscale, backswimmer inspired robot (BackBot) with auto-buoyancy regulation\nthrough controlled nucleation and release of microbubbles. The bubbles nucleate\nand grow directly on onboard electrodes through electrolysis, regulated by low\nvoltage. We use 3D printing to introduce a three-dimensional bubble-entrapping\ncellular structure, in order to create a stable external gas reservoir. To\nreduce buoyancy forces, the bubbles are released through linear mechanical\nvibrations, decoupled from the robot's body. Through pressure sensing and a\nProportional Integral Derivative control loop mechanism, the robot\nauto-regulates its buoyancy to reach neutral floatation underwater within\nseconds. This mechanism can promote the replacement of traditional and\nphysically larger buoyancy regulation systems, such as pistons and pressurized\ntanks, and to enable the miniaturization of Autonomous Underwater Vehicles.\n