TECHNOLOGY AREA(S): Battlespace, Sensors

ACQUISITION PROGRAM: Commander, Naval Meteorology and Oceanography Command

OBJECTIVE: Develop and demonstrate a jellyfish-inspired autonomous ocean observation float that makes oceanographic and water quality measurements, stores and transmits the resulting data, can relay data from Unmanned Underwater Vehicles (UUVs), and is low-power, with power provided by energy scavenging and sustainable energy sources.

DESCRIPTION: Current subsurface oceanographic sensing is provided by expensive UUVs and gliders capable of sampling large areas or by tethered floats or buoys that are for sampling a restricted area.� The typically passive, distributed, battery-operated wireless sensor nodes are not desirable as they have limited station-keeping capability and fixed lifetimes.� The goal of this research is to develop an autonomous, jellyfish-inspired vehicle that is capable of conducting autonomous station-keeping in dynamic environments to act as an oceanographic sensor node for 2-12 months.� These nodes should be inexpensive so that many of them can be deployed in a region of interest.� The strategy adopted to accomplish this goal is to implement methods of underwater propulsion found in biological species.

Nature comprises a variety of animal designs that show promise for surveillance in underwater environments.� They can be mobile, small with various sensory functions, and networked as nodes with other units as well as possess adaptability, maneuverability, and intelligence.� Out of the broad range of choices, jellyfish were selected due to attributes such as their ability to consume little energy owing to a lower metabolic rate than other marine species, survivability in varying water conditions and possession of adequate morphology for carrying payload.� Jellyfish inhabit every major oceanic area of the world and are capable of withstanding a wide range of temperatures and salinities.� Most species are found in shallow coastal waters, but some have been found at depths of 7,000 meters (m).� Furthermore, jellyfish are found in a wide variety of sizes ranging from a few millimeters to over 2 m in diameter [3] as well as displaying a multitude of shapes and colors.

This morphological variability opens options and capabilities for large mass payloads, energy harvesting from solar using a large deployed surface area in the bell, and energy scavenging from the tentacles.� They have the ability to move vertically, correct their heading and position using fluid manipulation to impart turning moments, and utilize ocean currents for horizontal movement.� In addition, the progress achieved in developing microbial fuel cells and understanding of suspension feeding mechanism provides opportunity to develop a sustainable power source for the UUV.� Recently, several laboratories have constructed artificial jellyfish that are propelled by artificial muscles or shape memory actuators, showing the feasibility of this type of mobility.� These artificial jellyfish demonstrated controlled ascent and descent in a laboratory setting.� This combination of simple control and body plans, efficient and effective position control in active environments, and large scales to support large sensor and communication payloads with the required power systems make a jellyfish-inspired robot viable for low cost, high reliability with integrated fault correction, and long-term endurance ocean sensing and communication relay applications.

PHASE I: Conduct a study on the feasibility of a jellyfish-inspired vehicle design, with a focus on mobility mechanism and power source.� This should draw on prior biological research on jellyfish kinematics, dynamics, and fluid interactions to support design of a vehicle with station-keeping in a current of 1-2 cm/sec, and localized maneuver in the water column.� Identify the most promising actuation mechanism, including power requirements and expected lifetime.� Conduct a design study of the feasibility of different sustainable power sources (e.g., solar, mechanical energy scavenging, microbial fuel cells) and specify the expected mission duration.� Identify materials with surfaces that resist fouling.� Develop a Phase II plan.

PHASE II: Fully develop and fabricate a jellyfish-inspired vehicle that has the payload and structural capability to carry oceanographic sensors (e.g., water temperature, salinity, ambient noise and turbidity, GPS), sensors to measure the wave field (directional wave spectra, peak period and direction) and communication electronics and power systems.� Design a means of projecting an antenna capable of supporting Iridium communications.� The ability to relay underwater acoustic communication from another underwater system and transmit data via radio frequency (RF) should be considered.� The power systems identified in Phase I should be able to support equipment payloads, as well as minimal power expenditure for station-keeping and maneuvering.� The vehicle will be able to maintain a position within a 2-meter radius, including maneuvering to correct drift and environmental external impacts.� Demonstrate controlled vertical descent to 50 feet.� Demonstrate the vehicle and a suite of relevant oceanographic sensors in an ocean environment.

PHASE III DUAL USE APPLICATIONS: Implementation control and maneuverability optimization, finalize integrated power systems for efficient motion and increased mission duration, implement energy harvesting such as solar recharging to indefinitely increase power and duration capabilities, and improve design reliability and durability for live aquatic environments.� The improved platform will be tested in simulated and limited live environments to prove final product viability and final changes for optimal performance.� Design a plan of employment for multiple jellyfish vehicles including deployment procedure and strategy for coverage in the face of drift.� Demonstrate the vehicle in a complete mission scenario for ocean sensing within an IPOE (Intelligence Preparation of the Operational Environment).� Commercial applications include scientific oceanography, monitoring of remediation and ecosystem health, fisheries management, and harbor water monitoring.

REFERENCES:

1. Gemmell, BJ, Troolin, DR, Costello, JH, Colin, SP, and Satterlie RA. �Control of vortex rings for maneuverability.� J. R. Soc. Interface 2015 12: 20150389. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4528605/

2. Villanueva, A., Smith, C., and Priya, S. �A biomimetic robotic jellyfish (Robojelly) actuated by shape memory alloy composite actuators.� Bioinspiration & Biomimetics 6(3), 2011, 036004. http://iopscience.iop.org/article/10.1088/1748-3182/6/3/036004/meta

3. Omori, M and Kitamura, M. �Taxonomic review of three Japanese species of edible jellyfish (Scyphozoa: Rhizostomeae).� Plankton Biology and Ecology 51:36-51. http://www.plankton.jp/PBE/issue/vol51_1/vol51_1_036.pdf

4. Priya, S. and Inman, D.J. �Energy Harvesting Technologies.� Springer-Verlag. http://www.springer.com/us/book/9780387764634

5. Tadesse, Y. �Electroactive polymer and shape memory alloy actuators in biomimetics and humanoids.� Proc. SPIE 8687, Electroactive Polymer Actuators and Devices (EAPAD) 2013, 868709. http://proceedings.spiedigitallibrary.org/proceeding.aspx?articleid=1677453

6. Tadesse, Y., Villanueva, A., Haines, C, Novitski, D, Baughman, R., and Priya, S. �Hydrogen-fuel-powered bell segments of biomimetic jellyfish.� Smart Materials and Structures, 21(4), 045013. http://iopscience.iop.org/article/10.1088/0964-1726/21/4/045013/meta

7. Larkin, M. and Tadesse, Y. �HM-EH-RT: Hybrid multimodal energy harvesting from rotational and translational motions.� International Journal of Smart and Nano Materials. 4(4), 257-285. http://www.tandfonline.com/doi/abs/10.1080/19475411.2014.902870

KEYWORDS: Unmanned Underwater Vehicle; Bio-inspired; Low Energy; Energy Harvesting; Oceanographic Sensing; Profiling Floats