Robotic Eels Using Electrolytic Hydraulics For Long-Duration Autonomous Soil Surveying
Abstract
The sea floor is made of many different sediment types, from clays to biogenous oozes. Information about the sea floor at a build site is important in marine geotechnical engineering, since it dictates design decisions such as which type of anchor or pile to install for a marine structure. This information is expensive, however: marine geotechnical surveys are much more difficult than corresponding land-based surveys. Physical soil samples are an important part of geotechnical surveys, but they are difficult to retrieve, and sample quality suffers during the retrieval process. Surveying devices tethered to a ship, such as corers and ROVs, suffer loss of accuracy, require constant attendance, and are subject to weather related issues. Autonomous Underwater Vehicles (AUVs) solve these issues, and have been used for some surveying tasks, but are not generally used for physical soil sampling. Current methods of physical soil sampling are energy intensive, and AUVs are limited by their battery life. An AUV with capability to do soil sampling for a full site would both reduce survey expense and give better information for construction decisions. Engineering this capability requires more efficient sampling methods and better energy storage.Modeling a soft AUV based on bioinspiration from a Garden Eel should allow us to build an anguilliform swimmer that can quickly move between soil sampling points. The artificial eel can than use undulatory and peristaltic motion to aid in burrowing and pressure-meter analysis of the local seafloor mechanical properties. Aiding in the operational lifetime of this artificial eel will be the multifunctional use of Redox Flow Battery (RFB) hydraulic fluids as actuators. Based on prior work, we believe this RFB Artificial Eel could sample soil for more than 40 hours before needing to be recharged. Based on our prior work, the eel should be able to swim at a rate well in excess of 0.1 m s-1. Digging efficiencies will need to be determined and optimized.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- May 08, 2020
- Source ID
- N000142012438
Entities
People
- Robert F Shepherd
Organizations
- Cornell University
- Office of Naval Research
- United States Navy