Unmanned Mobile Sensor Net- Ben Snively

Unmanned Underwater Gliders

Survey and extensions to work from:COOPERATIVE CONTROL OF COLLECTIVE MOTION FOR OCEAN SAMPLING WITH AUTONOMOUS VEHICLES; Derek A. Paley

University of Central Florida

Manual Ocean Sampling labor, resource, and time intensive.

Objectives/Sensing Gradient Climbing Feature Tracking Boundary Monitoring Perimeter Surveillance Mapping

Autonomous Distributed Agents both reduce over costs, improve accuracy, and reduce latency for critical data.

Problem / Motivation

University of Central Florida

Marine Sensing Equipment

NOAA Manual Ocean Survey Ships with complex survey equipment Performs in both shallow and deep

water collections.

AUV – Autonomous Underwater Vehicle Shallow water survey using GPS and

Satellite communication

University of Central Florida

Sensor Network Details

Sink Satellite Communication

Agents/Sensors Mobile Gliders Every Glider in Range of Sink / GPS

Satellite only communicate with satellite when at surface

Cannot control movement at surface (just floats) – has control only when submerged.

GCCS – Glider Coordinated Control System GCCS steers groups/sets of gliders Gliders controlled remotely No Agenda/Beliefs/Planning

GCCS

University of Central Florida

Overview

“Apply a cooperative control methodology to control a fleet of autonomous underwater gliders. Underwater gliders soar through the water on a pair of fixed wings, collecting valuable oceanographic data for weeks at a time. We describe the Glider Coordinated Control System (GCCS), which steers multiple gliders to a set of coordinated trajectories. The GCCS automatically controlled up to six gliders continuously for over three weeks in a 800 km2 region in California’s Monterey Bay in August 2006. The GCCS enables oceanographers to specify and adapt glider sampling patterns with minimal human intervention.”(Paley)

University of Central Florida

Mobile Sensors and Sink

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Domain Definition

Domain:Outer Search Area

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Domain Example<domain>

<rectangle><x>

<units>deg</units><value>-122.3817</value>

</x><y>

<units>deg</units><value>36.9765</value>

</y><a>

<units>met</units><value>20000</value>

</a><b>

<units>met</units><value>10000</value>

</b><ori>

<units>deg</units><value>137</value>

</ori>

</rectangle></domain>

Center Point Longitude

Center Point Longitude

Width

Height

Angle

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Search Paths

Tracks Search Paths

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Tracks Example<tracks>

<superellipse><name>track1</name><x>

<units>deg</units><value>-122.2713</value>

</x><y>

<units>deg</units><value>36.8950</value>

</y><a>

<units>met</units><value>10000</value>

</a><b>

<units>met</units><value>6667</value>

</b><ori>

<units>deg</units><value>47</value>

</ori><p>

<value>3</value></p>

</superellipse></tracks>

Shape/Name

Center Point

Width

Height

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Glider Groups

Glider Tree:Entities, which paths to use,Comm model.

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Glider Groups Example

<group><group>

<phase> <value>0</value> <units>pct</units>

</phase><glider>

<mnf>w</mnf> <!-- Manufacturer --><sn>7</sn> <!-- Serian Number --><model>e</model><track>track1</track><direction>1</direction><phase> <!-- Curve Phase -->

<value>0</value><units>pct</units>

</phase><control> sellipse control </control>

</glider><glider> . . . </glider>

</group></group>

University of Central Florida

YAES Simulations

Simulations Performed

1. 4 Boundary Gliders rotating same direction

2. 4 Boundary and 6 Interior Sensors, All positioned in ideal/planned position.

3. 4 Boundary and 6 Interior Gliders, all starting from hub location

Actual software from research done in Matlab. Software allows for both simulated and real tests

University of Central Florida

Background Information on Simulation

XML Configurations drive simulation setup and context. Much like the Real system, xml configuration files define gliders,

tracks, and other system configuration. (The XML Schema was slightly modified in order to simplify configuration)

Main Simulation class allows for selection of which simulation to perform.

JAXB used to parse XML Input / Java 1.6 SDK/Runtime(JAXB = Java API for XML Binding)

University of Central Florida

Simulation 1: Boundary Test

Sink Communication at surface4 Boundary Gliders

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Simulation 2 : Interior Gliders

6 Interior Gliders covering Area3 Groups, 2 Gliders in each.(Gliders communicate w/ Sink at Surface)

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Simulation 3 : Boundary and Interior Gliders

Sink Communication at surface4 Boundary Gliders6 Interior Gliders

Flow adds error (off track) when Glider is at surface

University of Central Florida

Extending Network

Current Limitations Central control/Planning Planning communication only done at surface

(when gliders are floating and have no control – drift) Limited Inter-glider communication.

Extending Sensor network principals to the system Gliders become agents with beliefs, agendas, and planning Sensor communication models and MDP principals

(Specifically Partially Observable - MDP) This is critical due to the fluxations and inconsistencies in the robot

control.

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Glider Agents

Key Difference Glider has Agenda, Goal, and isn’t pure input/sensing device.

Glider communicate with each other Goal:

Cover area (and plan) that hasnot been covered by other agents.

Inform others plan/area covered.

Single Sink transmitter could be at surface, to bridge under-water to satellite gap.

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Planning / Decision Process

PO-MDP (Partially Observable Mark-ov Decision Process. Outcome from Glider commands uncertain.

Policy mapping between States / Actions Perceived new State.

Routing issues isn’t applicable due to every glider having access to the sink (via satellite). Routing issues could be introduced in a more complex system where

messages between gliders and to sink are transmitted.

University of Central Florida

Questions?

Questions / Comments?

Thank you.