A novel electroactive polymer buoyancy control device for bio-inspired underwater vehicles

Um, Tae I.; Chen, Zheng; Bart‐Smith, Hilary

doi:10.1109/icra.2011.5980181

Cited by 24 publications

(4 citation statements)

References 12 publications

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“…Overall, the Backbot ascends and descends while consuming power in the range of dozens of Joules, compared with energy consumption of hundreds and thousands of Joules in other devices. [45][46][47][48] See also Table S1, Supporting Information. The reason for the reduced energy consumption is attributed to the effective density of the device, almost matching the density of water.…”

Section: Bubble Release Through Linear Vibrationsmentioning

confidence: 99%

Backswimmer‐Inspired Miniature 3D‐Printed Robot with Buoyancy Autoregulation through Controlled Nucleation and Release of Microbubbles

Kobo

Pinchasik

2022

Advanced Intelligent Systems

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The backswimmer is an aquatic insect, capable of regulating its buoyancy underwater. When it enters the water, it entraps an air bubble in a superhydrophobic hairy structure covering its abdomen. While this bubble is mainly used for respiration, it also functions as an external inflatable gas reservoir for buoyancy regulation. Namely, hemoglobin is used to store and release oxygen to the entrapped bubble, reversibly. This way, it can reach neutral buoyancy without further energy consumption. Herein, a small, centimeter‐scale, backswimmer‐inspired untethered robot (BackBot) with autobuoyancy regulation through controlled nucleation and release of microbubbles is developed. The bubbles nucleate and grow directly on onboard electrodes through electrolysis, regulated by low voltage. A bubble‐entrapping 3D‐printed canopy is introduced to create a stable external gas reservoir. To reduce buoyancy forces, the bubbles are released through linear mechanical vibrations of the canopy, decoupled from the robot's body. Through pressure sensing and a proportional integral derivative control loop mechanism, the robot autoregulates its buoyancy to reach neutral floatation underwater within seconds. This mechanism can promote the replacement of traditional, and physically larger, buoyancy regulation systems such as pistons and pressurized tanks, and enables the miniaturization of autonomous underwater vehicles.

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Section: Bubble Release Through Linear Vibrationsmentioning

confidence: 99%

Backswimmer‐Inspired Miniature 3D‐Printed Robot with Buoyancy Autoregulation through Controlled Nucleation and Release of Microbubbles

Kobo

Pinchasik

2022

Advanced Intelligent Systems

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“…A third mechanism imitates ray-finned fish, which adjust the volume of their bladders to adjust their buoyancy [12]. They employ polymer buoyancy control device [13]. Electrolysis is used to generate pure hydrogen, which is a clean gas, in order to expand the volume of an artificial bladder leading to a displacement of water and an increase of buoyancy.…”

Section: David Publishingmentioning

confidence: 99%

Depth and Altitude Control of an AUV Using Buoyancy Control Device

Choyekh¹,

Kato²,

Dewantara³

et al. 2016

JEE

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A new method for depth control was developed for a spilled oil and blow out gas tracking autonomous buoy robot called SOTAB-I by adjusting its buoyancy control device. It is aimed to work for any target depth. The new method relies on buoyancy variation model with a depth that was established based on experimental data. The depth controller was verified at sea experiments in the Toyama Bay in Japan and showed good performance. The method could further be adapted to altitude control by combining the altitude data measured from bottom tracking through a progressive depth control. The method was verified at the sea experiments in Toyama in March 2016 and showed that the algorithm succeeded to bring the robot to the target altitude.

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“…Divers' BCD (Buoyancy Control Device) implements a similar concept by inflating bags of air, thus the density is manipulated by volume increase at constant mass. Recent designs [6] are using IPMC transducers as high surface area electrodes for a low power buoyancy engine. Electrolysis at the IPMC electrodes generates hydrogen and oxygen gas which replace the water in the gas chamber resulting in the floatation of the engine.…”

Section: Introductionmentioning

confidence: 99%

Biologically inspired highly efficient buoyancy engine

et al. 2012

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Undersea distributed networked sensor systems require a miniaturization of platforms and a means of both spatial and temporal persistence. One aspect of this system is the necessity to modulate sensor depth for optimal positioning and station-keeping. Current approaches involve pneumatic bladders or electrolysis; both require mechanical subsystems and consume significant power. These are not suitable for the miniaturization of sensor platforms. Presented in this study is a novel biologically inspired method that relies on ionic motion and osmotic pressures to displace a volume of water from the ocean into and out of the proposed buoyancy engine. At a constant device volume, the displaced water will alter buoyancy leading to either sinking or floating. The engine is composed of an enclosure sided on the ocean's end by a Nafion ionomer and by a flexible membrane separating the water from a gas enclosure. Two electrodes are placed one inside the enclosure and the other attached to the engine on the outside. The semi-permeable membrane Nafion allows water motion in and out of the enclosure while blocking anions from being transferred. The two electrodes generate local concentration changes of ions upon the application of an electrical field; these changes lead to osmotic pressures and hence the transfer of water through the semi-permeable membrane. Some aquatic organisms such as pelagic crustacean perform this buoyancy control using an exchange of ions through their tissue to modulate its density relative to the ambient sea water. In this paper, the authors provide an experimental proof of concept of this buoyancy engine. The efficiency of changing the engine's buoyancy is calculated and optimized as a function of electrode surface area. For example electrodes made of a 3mm diameter Ag/AgCl proved to transfer approximately 4mm 3 of water consuming 4 Joules of electrical energy. The speed of displacement is optimized as a function of the surface area of the Nafion membrane and its thickness. The 4mm 3 displaced volume obtained with the Ag/AgCl electrodes required approximately 380 seconds. The thickness of the Nafion membrane is 180µm and it has an area of 133mm 3 .

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A novel electroactive polymer buoyancy control device for bio-inspired underwater vehicles

Cited by 24 publications

References 12 publications

Backswimmer‐Inspired Miniature 3D‐Printed Robot with Buoyancy Autoregulation through Controlled Nucleation and Release of Microbubbles

Backswimmer‐Inspired Miniature 3D‐Printed Robot with Buoyancy Autoregulation through Controlled Nucleation and Release of Microbubbles

Depth and Altitude Control of an AUV Using Buoyancy Control Device

Biologically inspired highly efficient buoyancy engine

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