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

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

IAS-6 July 26, 2000 Software Architecture Models Centralized Distributed optimal intractable brittle sluggish communication heavy suboptimal tractable robust nimble communication light

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

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

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

IAS-6 July 26, 2000 Simple Reasoning Robot 1 profit = 20 Robot 2 profit = 30 Subcontract: ( ) / 2 = 130 Robot 1 profit: 40 (20) Robot 2 profit: 50 (30) Robot 1 Robot 2 Task A = 120 Task B = Robot 1 Robot 2 Task A = 120 Task B = More Complex Reasoning

IAS-6 July 26, 2000 Architectural Framework Resources Locomotor Sensors CPU Radio Roles Mapper Comm Leader Negotiations Robot Exec Tasks Send Message to “B” Map Area “X” Negotiation Protocol Learning Module Other Agents

IAS-6 July 26, 2000 Agent Interaction Operator Exec Revenue paid Tasks performed Operator (GUI) Robots

IAS-6 July 26, 2000 Simple Mapping Simulation InitialFinal Initial Assignments R2 R1 Final Tours R2 R1

IAS-6 July 26, 2000 More Complex Mapping Simulation Initial Final

IAS-6 July 26, 2000 X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X Adaptive Response to Dynamic Conditions Cities Tours X X X X X X X X X X X X X X X X X X X X

IAS-6 July 26, 2000 Current Status  Mapping example of architecture implemented  Robot platforms up and running

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

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