Showing papers on "iRobot Seaglider published in 2014"

High-level fuzzy logic guidance system for an unmanned surface vehicle (USV) tasked to perform autonomous launch and recovery (ALR) of an autonomous underwater vehicle (AUV)

Abstract: There have been much technological advances and research in Unmanned Surface Vehicles (USV) as a support and delivery platform for Autonomous/Unmanned Underwater Vehicles (AUV/UUV) or Remotely Operated Vehicles (ROV). Advantages include extending underwater search and survey operations time and reach, improving underwater positioning and mission awareness, in addition to minimizing the costs and risks associated with similar manned vessel operations. The objective of this paper is to present the design and development a high-level fuzzy logic guidance controller for a WAM-V 14 unmanned surface vehicle (USV) in order to autonomously launch and recover a REMUS 100 autonomous underwater vehicle (AUV). The approach to meeting this objective is to develop ability for the USV to intercept and rendezvous with an AUV that is in transit in order to maximize the probability of a final mobile docking maneuver. Specifically, a fuzzy logic Rendezvous-Docking controller has been developed that generates Waypoint-Heading goals for the USV to minimize the cross-track errors between the USV and AUV. A subsequent fuzzy logic Waypoint-Heading controller has been developed to provide the desired heading and speed commands to the low-level controller given the Waypoint-Heading goals. High-level mission control has been extensively simulated using Matlab and partially characterized in real-time during testing. Detailed simulation, experimental results and findings will be reported in this paper.

Preliminary results in under-ice acoustic navigation for seagliders in Davis Strait

Abstract: This paper presents an under-ice acoustic navigation system developed for Seaglider, a buoyancy-driven autonomous underwater vehicle (AUV), and post-processed navigation results from one of fourteen glider deployments between 2006 and 2014 in Davis Strait. Seagliders typically receive all geolocation information from global positioning system (GPS) signals received while they are at the surface, and perform dead reckoning while underwater. Extended under-ice deployments, where access to GPS is denied due to the inability of the glider to surface, require an alternative source of geolocation information. In the deployments described herein, geolocation information is provided by range measurements from mooring-mounted acoustic navigation sources at fixed, known locations. In this paper we describe the navigation system used in Davis Strait and present navigation results from a six degree-of-freedom Kalman filter using post-processed navigation data.

Seaglider observations of equatorial Indian Ocean Rossby waves associated with the Madden-Julian Oscillation

Abstract: During the CINDY–DYNAMO field campaign of September 2011–January 2012, a Seaglider was deployed at 80°E and completed 10 north-south sections between 3 and 4°S, measuring temperature, salinity, dissolved oxygen concentration, and chlorophyll fluorescence. These high-resolution subsurface observations provide insight into equatorial ocean Rossby wave activity forced by three Madden-Julian Oscillation (MJO) events during this time period. These Rossby waves generate variability in temperature O(1°C), salinity O(0.2 g kg−1), density O(0.2 kg m−3), and oxygen concentration O(10 μmol kg−1), associated with 10 m vertical displacements of the thermocline. The variability extends down to 1000 m, the greatest depth of the Seaglider observations, highlighting the importance of surface forcing for the deep equatorial ocean. The temperature variability observed by the Seaglider is greater than that simulated in the ECCO-JPL reanalysis, especially at depth. There is also marked variability in chlorophyll fluorescence at the surface and at the depth of the chlorophyll maximum. Upwelling from Rossby waves and local wind stress curl leads to an enhanced shoaling of the chlorophyll maximum by 10–25 m in response to the increased availability of nutrients and light. This influence of the MJO on primary production via equatorial ocean Rossby waves has not previously been recognized.

Design and development of an under-ice autonomous underwater vehicle for use in Polar regions

Abstract: Presented here is the initial hardware and software design of the Icefin autonomous underwater vehicle for use in under-ice missions in Antarctica. Exploration of the ocean beneath hundreds of meters of ice in Antarctica is a difficult task. However, many areas of science are interested in obtaining data from this environment and other similar environments including Jupiter's moon Europa. Deployment of an unmanned underwater vehicle to obtain data beneath Earth's ice shelves is much less dangerous and expensive than manned submarines or human diver deployments. However, the under-ice environment presents many unique challenges for an unmanned underwater vehicle including deployment through a small ice hole and extreme temperatures. The Icefin vehicle is designed as a modular, man portable, vertically deployed vehicle able to withstand the environmental challenges of the Polar Regions and the extreme depths required for the missions of interest. The Icefin has been designed with a full sensor suite to facilitate the necessary scientific data collection. The software suite used by the vehicle is designed around the MOOS middleware framework. This vehicle is slated to be deployed in Antarctica starting October 2014.

Diversity-based acoustic communication with a glider in deep water

Abstract: The primary use of underwater gliders is to collect oceanographic data within the water column and periodically relay the data at the surface via a satellite connection. In summer 2006, a Seaglider equipped with an acoustic recording system received transmissions from a broadband acoustic source centered at 75 Hz deployed on the bottom off Kauai, Hawaii, while moving away from the source at ranges up to ∼200 km in deep water and diving up to 1000-m depth. The transmitted signal was an m-sequence that can be treated as a binary-phase shift-keying communication signal. In this letter multiple receptions are exploited (i.e., diversity combining) to demonstrate the feasibility of using the glider as a mobile communication gateway.

Analysis of Autonomous Underwater Gliders Motion for Ocean Research

Abstract: Underwater gliders, a type of highly efficient underwater vehicle which uses gravity and buoyancy for propulsion, has been studied for a long time during the last 3 decades. This paper describes the development of the principle dynamic models of a general underwater glider, including hydrodynamic forces and buoyancy effects. The numerical analysis model was developed for the underwater glider motion. Dynamic forces equations including the model’s buoyancy, gravity, and hydrodynamic forces in gliding are derived. Gliding velocities with changes of the net buoyancy are compared. The numerical method was used to calculate the hydrodynamics coefficient of the glider. Dynamic characteristics of the Seaglider and SLOCUM have been used as validation objects for the numerical method. The glide angle is merely the function of the lift/drag ratio and has no relation to the net buoyancy. The gliding velocity would increase when the buoyancy increases.© 2014 ASME

Operational glider monitoring, piloting, and communications

Abstract: The Glider Operations Center (GOC) at the Naval Oceanographic Office (NAVOCEANO) is responsible for operating a fleet of autonomous unmanned systems, including ocean gliders, in the collection of physical oceanography data. The data collected include ocean temperature, salinity, and optical properties, which are profiled at depth and used by ocean modelers to forecast future environmental ocean conditions. NAVOCEANO then provides these forecasts in near-real time to support strategic, operational, and tactical Navy fleet requirements and activities. The Glider Monitoring, Piloting, and Communications (GLMPC) interface is a tool used by the GOC for command and control of ocean gliders and other unmanned surface vehicles. Vehicles controlled by GLMPC include the Littoral Battlespace Sensing-Glider (shallow and deep varieties), Kongsberg Seaglider, and Liquid Robotics Wave Glider. GLMPC provides the glider pilot with the ability to change and adjust missions, plan and adjust routes, review vehicle data profiles and statistics, compare dives and profiles of multiple vehicles in one area, and view vehicle diagnostics. Each type of autonomous vehicle is produced by the respective manufacturer with its own user interface, complete with a special set of commands only that type of vehicle can understand. GLMPC provides a pilot the ability to communicate with multiple types of vehicles simultaneously via a graphical user interface (GUI). GLMPC converts the GUI instructions into the specific commands expected by each vehicle type. This significantly reduces the number of commands a pilot is required to manually issue to vehicles and increases the number and types of vehicles that can be effectively operated at once. Future enhancements to GLMPC are planned to include Glider Observation Strategies (GOST) software, developed by the Naval Research Laboratory, which will automate the generation of planned vehicle tracks to be ingested by GLMPC. Other enhancements to GLMPC include the ability to display quality-controlled data and raw data for comparison purposes. Currently only raw data are displayed. Display of real-time weather and/or wind forecast data is also being explored.

Underwater topography measurement and observation in Southwest Taiwan using unmanned underwater vehicles

Abstract: With the depletion of land resources, marine resources development and utilization become increasingly apparent. Accompanied by the development of marine resources from nearshore extension to the deep ocean, Unmanned Underwater Vehicles (UUVs) become key instruments. Generally, UUVs include autonomous and tethered types; each has its advantages and disadvantages. Through the use of combined vehicle systems, we could take advantages of both systems. With the recent advent of seafloor observatories, deep submergence science is poised to enter a new research era where scientists will gain a more detailed understanding of various seafloor features. In this study, the Autonomous Underwater Vehicle (AUV) path planning in west Good Weather Ridge (119 55', 22 15') with the multi-beam echo sounder to obtain underwater topography. In order to observation the environment, the Remotely Operated Vehicle (ROV) is hired to carry out the terrain image at 1350m water depth in detailed. This experience will help to build future underwater investigation capabilities.

Bio-optical and hydrographic characteristics of the western Pacific Ocean for undersea warfare using SEAGLIDER data

Abstract: : Analysis of hydrographic and optical variability in the western Pacific Ocean region is conducted using data collected by Naval Oceanographic Office (NAVOCEANO) from March 2008 to November 2011. Temporal and spatial patterns of temperature, salinity, optical scattering, and fluorescence were examined. Vertical charts of each variable were produced for environmental and operational characterization. Histograms of the maxima and minima were plotted to examine the frequency of these variables. Furthermore, the vertical correlations among the variables were identified.

Study on Structural and Hydrodynamics of Autonomous Underwater Gliders

Abstract: Underwater gliders are autonomous underwater vehicles that use buoyancy to convert horizontal to vertical displacement to propel underwater. The most famous and common AUGs in the market are Slocum, Seaglider, Spray, and LiberdadeXray. All these gliders serve at different operating depth and payload. However, external forces and hydrodynamic forces are important to define the operational capacity of an AUG. Experimentally, it is expensive and difficult to determine the behaviour of structural and hydrodynamic forces. Therefore simulation is used to optimize the structural and hydrodynamics of the AUGs. There are two types of analysis proposed to compare both Slocum and Seaglider which are structural FEA and hydrodynamic CFD analysis. For structural FEA analysis, CATIA Dessault software is used meanwhile ANSYS FLUENT is used to analysis hydrodynamic performance of these AUGs. For the structural analysis, FEA modelling has been used to test the Von Mises stress and buckling of three types of materials on the AUGs hull body. On the other hand, hydrodynamic performance of the AUGs are tested to interpret the coefficient of lift, coefficient of drag and lift to drag ratio generated on Slocum and Seaglider at different angle of attacks (-15° − +15°). For this project, these findings are to be compared between the chosen gliders based on structural and hydrodynamic performance. From structural perspective, it is found that Seaglider has better hull body performance compared to Slocum because Seaglider is designed at thicker hull thickness and higher buckling resistance compare to Slocum. Based on hydrodynamic performance, Seaglider also has higher performance than Slocum because Seaglider produced less drag and higher lifted when simulated at different angles of attacks. This is because an AUG shape greatly influences its hydrodynamic performance. Seaglider has shape more closely to NACA airfoil design which performs to have less drag and higher lift.

Autonomous Underwater Vehicles for Cooperative Surveys of Deep-Water Sites

Abstract: Experimental results obtained with the Autonomous Underwater Vehicles developed in the “Thesaurus” project are reported. The Thesaurus AUVs, “Typhoon”, are low-cost torpedo-shaped 300 m depth-rated vehicles implementing a distributed communication and localization scheme based on acoustic modems, one of them with Ultra Short Base Line (USBL) capabilities. Communication and localization results obtained in the experimentation of the Thesaurus project and the CMRE (NATO Ctr. Maritime Res. Exp.) cruise CommsNet13 show that the modem-based acoustic localization has the capacity of correcting the navigation drift of low-cost inertial units even at the very low and time-varying communication rates encountered in experimental conditions.

Autonomous Underwater Vehicle System Implementation in Xingda Harbor

Abstract: In the recent decades, Autonomous Underwater Vehicles (AUVs) are remarkable machines that revolutionized the process of gathering ocean data. AUV systems have been developed, operated, marketed, produced, sold and utilized in water for various purposes. Accordingly, in this study, the IVER2 AUV which configuration by Taiwan Ocean Research Institute (TORI) and built by OceanServer is discussed. The IVER2 performs routine operations sea surface; all the components are rated to 100 m.

Development of underwater mobile robot AQUA-X with new maneuvering method

Abstract: Article history: Received 20 November 2013 Received in revised form 24 January 2014 Accepted 29 January 2014 Available online 25 February 2014

Autonomous underwater vehicle system trajectory tracking in Xingda harbor

Abstract: Underwater data collection by using Autonomous Underwater Vehicles (AUVs) is increasing within the oceanographic research community AUVs are remarkable machines that processed data for gathering local bathymetric information, which have been developed, investigated and utilized for various purposes In this study, the Iver2 AUV is examined to accomplish location mapping by well-planned trajectory while executing missions The goal is to collect a large-scale Xingda harbor side-scan data Therefore, in this study, the Iver2 AUV configured by Taiwan Ocean Research Institute (TORI) and built by OceanServer is discussed The Iver2 performs routine operations at sea surface; all the components are rated to 100 meters

Online Coordinated Decentralized Localization of the Seaglider with Intermittent Observations

Abstract: As we discussed in Chap. 9 , packet drops in sensor networks can be modeled by random networks. We then developed a coordinated decentralized estimation procedure in the presence of packet drops.