The Robotics Institute

A Free Market Architecture for Distributed Control of a Multirobot System

The Robotics Institute

Carnegie Mellon University

M. Bernardine Dias

Tony Stentz

July 26, 2000

The Robotics Institute IAS-6 July 26, 2000

Motivation and Outline

Outline: Introduction Related Work The Free Market Architecture Initial Implementation Results Future Directions Acknowledgements and Questions

Motivation:

Effective control of multi-robot systems

The Robotics Institute IAS-6 July 26, 2000

Software Architecture Models

Centralized Distributed

• optimal• intractable• brittle• sluggish• communication heavy

• suboptimal• tractable• robust• nimble• communication light

The Robotics Institute IAS-6 July 26, 2000

Arkin, R. C., “Cooperation without Communication: Multiagent Schema-Based Robot Navigation” 1992

Arkin, R. C. et al., “AuRA: Principles and Practice in Review” 1997

Brooks, R. A., “Elephants Don’t Play Chess” 1990

Brumitt, B. L. et al., “Dynamic Mission Planning for Multiple Mobile Robots” 1996

Golfarelli, M. et al., “A Task-Swap Negotiation Protocol Based on the Contract Net Paradigm” 1997

Jensen, R. M. et al., “OBDD-based Universal Planning: Specifying and Solving Planning Problems for Synchronized Agents in Non-Deterministic Domains” 1999

Johnson, N. F. et al., “Volatility and Agent Adaptability in a Self-Organizing Market” 1998

Lux, T. et al., “Scaling and Criticality in a Stochastic Multi-Agent Model of a Financial Market” 1999

Matarić, M. J., “Issues and Approaches in the Design of Collective Autonomous Agents” 1995

Pagello, E. et al., “Cooperative Behaviors in Multi-Robot Systems through Implicit Communication” 1999

Parker, L. E., “ALLIANCE: An Architecture for Fault Tolerant Multi-Robot Cooperation” 1998

Schneider-Fontán, M.. Et al., “Territorial Multi-Robot Task Division” 1998

Schneider-Fontán, M. et al., “A Study of Territoriality: The Role of Critical Mass in Adaptive Task Division” 1996

Schwartz, R. et al., “Negotiation On Data Allocation in Multi-Agent Environments” 1997

Shehory, O. et al., “Methods for Task Allocation via Agent Coalition Formation” 1998

Smith, R., “The Contract Net Protocol: High-Level Communication and Control in a Distributed Problem Solver” 1980

Švestka, P. et al., “Coordinated Path Planning for Multiple Robots” 1998

Tambe, M., “Towards Flexible Teamwork” 1997

Veloso, M. et al., “Anticipation: A Key for Collaboration in a Team of Agents” 1998

Wellman, M. et al., “Market-Aware Agents for a Multiagent World” 1998

Zeng, D. et al.., “Benefits of Learning in Negotiation” 1997

Related Work

Sandholm, T. et al., “Issues in Automated Negotiation and Electronic Commerce: Extending the Contract Net Framework” 1995

The Robotics Institute IAS-6 July 26, 2000

Free Market Architecture

Robots in a team are organized as an economy Team mission is best achieved when the economy

maximizes production and minimizes costs Robots interact with each other to exchange money

for tasks to maximize profit Robots are both self-interested and benevolent,

since it is in their self interest to do global good

The Robotics Institute IAS-6 July 26, 2000

Architecture Features

Revenue, cost and profit Negotiation and price Competition vs. cooperation Role determined via comparative advantage Self organization Learning and adaptation

The Robotics Institute IAS-6 July 26, 2000

Simple Reasoning

Robot 1 profit = 20Robot 2 profit = 30

Subcontract: (150 + 110) / 2 = 130Robot 1 profit: 40 (20)Robot 2 profit: 50 (30)

Robot 1

Robot 2

Task A = 120 Task B = 180

50

75

110

100

60

Robot 1

Robot 2

Task A = 120 Task B = 180

50

75

110

100

60

More Complex Reasoning

The Robotics Institute IAS-6 July 26, 2000

Architectural Framework

Resources

Locomotor Sensors CPURadio

RolesMapper Comm Leader

Negotiations

RobotExec

TasksSend

Message to “B”

Map Area “X”

NegotiationProtocol

LearningModule

Other Agents

The Robotics Institute IAS-6 July 26, 2000

Agent Interaction

Operator Exec

Revenue paid

Tasks performed

Operator(GUI)

Robots

The Robotics Institute IAS-6 July 26, 2000

Simple Mapping Simulation

Initial Final

Initial Assignments

R2

R1

Final Tours

R2

R1

The Robotics Institute IAS-6 July 26, 2000

More Complex Mapping Simulation

Initial Final

The Robotics Institute IAS-6 July 26, 2000

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Adaptive Response to Dynamic Conditions

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The Robotics Institute IAS-6 July 26, 2000

Current Status

Mapping example of architecture implemented Robot platforms up and running

The Robotics Institute IAS-6 July 26, 2000

Future Work

Port architecture to robot test-bed Implement roles Synchronous -> asynchronous Limit communication Implement multi-task negotiation Implement broken deals with penalties Implement architecture in other robotic test-beds Benchmark against other architectures

The Robotics Institute IAS-6 July 26, 2000

Acknowledgements

The authors thank the members of the Cognitive Colonies group for their valuable contribution:

Vanessa De Gennaro

Bruce Digney

Brian Fredrick

Martial Hebert

Dave Kachmar

Bart Nabbe

Charles Smart

Scott Thayer