Isotherm Tracking by an Autonomous Underwater Vehicle in Drift Mode
| Autor: | Brian Kieft, Jason M. Smith, Monique Messié, John P. Ryan, Francisco P. Chavez, R. McEwen, M. Jordan Stanway, Brett Hobson, Ben Y. Raanan, Thomas C. O Reilly, James G. Bellingham, Yanwu Zhang |
|---|---|
| Rok vydání: | 2017 |
| Předmět: |
0209 industrial biotechnology
Buoyancy 010505 oceanography Mechanical Engineering Stratification (water) Ocean Engineering 02 engineering and technology engineering.material Atmospheric temperature range 01 natural sciences Frame of reference Isothermal process Sea surface temperature 020901 industrial engineering & automation Underwater vehicle Water column Control theory engineering Environmental science Electrical and Electronic Engineering 0105 earth and related environmental sciences Marine engineering |
| Zdroj: | IEEE Journal of Oceanic Engineering. 42:808-817 |
| ISSN: | 2373-7786 0364-9059 |
| DOI: | 10.1109/joe.2016.2625058 |
| Popis: | Studies of marine physical, chemical, and microbiological processes benefit from observing in a Lagrangian frame of reference. Some of these processes are related to specific density or temperature ranges. We have developed a method for a Tethys-class long-range autonomous underwater vehicle (LRAUV) (which has a propeller and a buoyancy engine) to track a targeted isothermal layer (within a narrow temperature range) in a stratified water column when operating in buoyancy-controlled drift mode. In this mode, the vehicle shuts off its propeller and autonomously detects the isotherm and stays with it by actively controlling the vehicle's buoyancy. The LRAUV starts on an initial descent to search for the target temperature. Once the temperature falls in the target center bracket, the vehicle records the corresponding depth and adjusts buoyancy to hold that depth. As long as the temperature stays within a tolerance range, the vehicle continues to hold that depth. If the temperature falls out of the tolerance range, the vehicle will increase or decrease buoyancy to reacquire the target temperature and track it. In a June 2015 experiment in Monterey Bay, CA, USA, an LRAUV ran the presented algorithm to successfully track a target isotherm for 13 h. Over the isotherm tracking duration, the LRAUV mostly remained in the 0.5 $^\circ $ C (peak-to-peak) tolerance range as designed, even though the water column's stratification kept changing. This work paves the way to coupling an LRAUV's complimentary modes of flight and drift—searching for an oceanographic feature in flight mode, and then switching to drift mode to track the feature in a Lagrangian frame of reference. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|