Developing a Low-Cost Robot Colony Association for the Advancement of Artificial Intelligence November 10, 2007 James Kong Felix Duvallet Austin Buchan Christopher Mar Bradford Neuman Kevin Woo Brian Coltin Eugene Marinelli

2 Colony Project Ongoing undergraduate research project Motivated team of 20 students Housed under the Carnegie Mellon Robotics Club – Building robots for fun since 1984 – Over 150 members

Motivation Why a robot colony? – Emergent behaviors – Cooperative behaviors – Multi-robot advantages Graceful degradation Distributed algorithms 3

4 Goals Open platform Low-cost robots Robust functionality Self-sustainability

5 Overview Colony Robots Behaviors Self-Sustainability Future Research

6 Dragonfly

Colony Robot Basic Features – Atmel ATMega128L – Differential drive – Orb LEDs – LCD expansion – USB interface – Rechargeable battery – Charging contacts – Sharp IR rangefinders 7

8 Colony Robot – Front View Front IR Rangefinders

9 Colony Robots – Back View Side IR Rangefinders

Colony Robot 10 8-bit AVR µcontroller XBee Wireless Module BOM USB Interface IR Rangefinders 5X LCD Screen Orb LEDs Motors/Wheels Functional Diagram

11 Communication Bearing and Orientation Module (BOM) – Localization sensor – IR emitter/detector array – Relative angle measurements to other robots

12 Communication XBee wireless module – 30m indoor range / 100m outdoor range – IEEE (ZigBee) – 2.4 GHz – Low-cost, low-power – Open industry standard

Communication Token Ring Coordination Scheme – Controls BOM activation – Ad-hoc Self-arranging Leaderless 13

Video - Lemmings Follow the Leader – Each robot follows the robot in front of it – Token ring coordination 14

Video - Lemmings 15

Communication Localization – Robots share relative angle data – Connectivity graph – Algorithms Shortest path between robots Determine relative positions 16

17 Cooperative Maze Solving Given a maze and a target, robots cooperate to seek the target Start

18 Cooperative Maze Solving Given a maze and a target, robots cooperate to seek the target Cooperation

19 Cooperative Maze Solving Given a maze and a target, robots cooperate to seek the target Goal

20 Video – Cooperative Maze Solving

21 Towards Self-Sustainability Goal: Self-sustainable robot colony – Long-term tasks Autonomous Recharging Remote Interface

Autonomous Recharging Detect battery levels Autonomously dock with a charging station Resume previous task 22

Autonomous Recharging Hardware – Charging station – Recharging circuitry – Homing system Software – Battery monitoring – Wireless integration 23

24 Autonomous Recharging IR Emitters Homing Beacon Homing Sensor

Left Center Right Max pulse width n 3n 2n Close-range Homing Process Autonomous Recharging

Bay Allocation – Treat charging bays as a resource – Minimize collisions Dynamically assign recharging robots to available bays Maximize distance between allocated bays

Video - Autonomous Recharging

Towards Self-Sustainability Long-term tasks 28

Remote Interface - ColoNet Connects Colony robots to users through the Internet Web interface ColoNet User Server TCP/IP Server Wireless R0R0 R1R1 RnRn Web client

Remote Interface - ColoNet Monitoring Tool – Behavior data – Visually monitor robots Debugging Tool – Direct robot control – Inspect robot states – Visualize connectivity Human-Robot Teams

Ongoing Research Object Manipulation SLAM Larger colony Longer tasks Remote Task Queuing 31

Acknowledgements Association for the Advancement of Artificial Intelligence Carnegie Mellon Robotics Institute – George Kantor – Matt Mason – Howie Choset – Peggy Martin Carnegie Mellon Undergraduate Research Office Carnegie Mellon Robotics Club Botrics LLC Special Thanks – Steve Shamlian – Pras Velagapudi – Aaron Johnson – All our past and current members 32

Contact Information Website – Mailing List – 34