1 Magnus Egerstedt - Summer 2009 Cooperative Foraging Among Bottlenose Dolphins: Search, Detect, and...

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Magnus Egerstedt - Summer 2009

Cooperative Foraging Among Bottlenose Dolphins: Search, Detect, and Capture

GRITSLabElectrical and Computer Engineering

Georgia Institute of Technologywww.ece.gatech.edu/~magnus

Magnus Egerstedt

Outline:

1. Bio-inspiration

2. Bottlenose dolphins

3. Foraging

4. Beyond biology

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My Comfort Zone

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Inspiration From Biology

• Thanks to Musad Haque (fearless graduate student) and Lori Marino (dolphin scientist) Bottlenose Dolphins, Tursiops truncatus, provide an exciting source of bio-inspiration of the hammer (rather than nail) variety

• Intelligent: Use tools, 2nd in EQ (among mammals)

• Complex social behaviors: Well-defined hierarchy, form alliances, advertise resources

• Mating: Form varied levels of alliances (alliances between alliances shift – only animal other than humans to do so)

• Foraging and capturing prey: Wall method, Carousel method

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Back to Biology

• The Simulated Dolphinarium - a synthetic environment that contains – interaction models – behavioral models – alliance forming – heterogeneity

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The Foraging Process

• Three Phases

– Search: Depends on threat level

– Detect: Depends on availability of fish

– Capture: Depends on number of dolphins

• Idea: Use tools from hybrid systems and networked control systems

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The Foraging Process: A Hybrid Model

• Threat level is assessed by leader agent to select search method

• If fish is found, agents converge to location of “advertizer”

• Leader takes a weighted poll to select a capturing method

• Foraging is halted whenever threat becomes too high

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Capture Phase: Methods

• Wall Method: Drive fish to a barrier• Four variations: Fish in front, Two columns, Dolphins as barrier, Two frontal attacks

• Horizontal Carousel: Encircle the school of fish• Tighten the encirclements to constrict maneuverability of prey• When circle is small enough, charge through to feed

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Dolphin-Fish Local Interaction Rules

fish

escape directionpredator set

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Horizontal Carousel

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Dolphin Group as Wall

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Two Columns

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Zone of No Escape

• “Theorem: Initial conditions from which the fish can never escape the dolphins”

• Single barrier:

• Double barrier:

fish are faster than dolphins dolphins are faster than fish

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P4 = Perpetual Porpoise Ping-Pong

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Beyond Dolphins - Conclusions

• Looking for meaningful “nails”

• Synchronized decisions? (no “backsies”)

• How use roles more efficiently?

• Automatically generated roles?

THANKS

Musad Haque(student – GT)

Amir Rahmani(postdoc – GT)

Lori Marino(professor - Emory)

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