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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. Problem / Motivation. Manual Ocean Sampling labor, resource, and time intensive.
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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
Problem / Motivation • 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.
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
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
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)
Domain Definition Domain: Outer Search Area
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
Search Paths Tracks Search Paths
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
Glider Groups Glider Tree: Entities, which paths to use, Comm model.
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>
YAES Simulations • Simulations Performed • 4 Boundary Gliders rotating same direction • 4 Boundary and 6 Interior Sensors, All positioned in ideal/planned position. • 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
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)
Simulation 1: Boundary Test Sink Communication at surface 4 Boundary Gliders
Simulation 2 : Interior Gliders 6 Interior Gliders covering Area 3 Groups, 2 Gliders in each. (Gliders communicate w/ Sink at Surface)
Simulation 3 : Boundary and Interior Gliders Sink Communication at surface 4 Boundary Gliders 6 Interior Gliders Flow adds error (off track) when Glider is at surface
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.
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.
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.
Questions? • Questions / Comments? • Thank you.