Developing a Low-Cost Robot Colony Felix Duvallet, James Kong, Eugene Marinelli, Kevin Woo, Austin Buchan, Brian Coltin, Christopher Mar, Bradford Neuman 20 mins pres + 5 mins questions = 25 minutes AAAI Fall Symposium 2007 November 10, 2007 Fix CMU logo – it looks out of place right now (probably move RC logo up or down)

Outline Motivation and Goals Robots Sensors Infrastructure Behaviors Sustainability Future work

Motivation and Goals Motivations – A low-cost experimental platform for multi-agent research – Tool for testing AI algorithms Need capable robots – Open-source software to promote similar research elsewhere Goal: Develop a colony of robots – Low-cost robots – Homogeneous architecture – Distributed algorithms Motivation and Goals Two hard things: experimental, and low-cost Remove open-source software?

Colony Robot BOMDragonfly Board Motors ORBs Range- Finders XBee Module Charging Contacts Robots Cheap (~$350) but capable

Colony Brains ATMega 128 – 8MHz max – 128Kbytes program memory Programmed in C – arv-libc, avr-gcc – open-source, multi- platform tools Robots

Sensors Sharp IR rangefinders BOM Also used: – Bump sensors – Pyroelectric sensors Sensors

BOM – Bearing and Orientation Module IR emitter/detector ring Emitter mode – All emitters are powered simultaneously (beacon) Detector mode – Detectors can be polled individually for analog intensity readings – Most excited sensor indicates bearing to emitting robot Co-planarity assumption Must coordinate BOMs Build connectivity graphs 1 20 Sensors

Wireless Infrastructure Integrate BOM and wireless network – Beaconing robot sends wireless message – Receiving robots know when to poll BOM Token-ring coordination scheme Share information about neighbors – Propagate global connectivity graph Infrastructure

Swarming Local obstacle avoidance Low coordination Highly scalable Behaviors

Lemmings Simple follow-the- leader Medium Coordination Variant: – Cooperative maze solving Behaviors

Towards Self-Sustainability Goal is to develop a self-sustainable robot colony that can operate unassisted for long periods of time Requirements – Autonomous recharging – Remote monitoring and control Sustainability

Autonomous Recharging Robots must request charging resources from a charging station Additional sensor aids homing sequence Daughter-board controls battery charging process Video? Sustainability

Bay Allocation Maximize distance between occupied bays – Minimize likelihood of collisions Can you really spend a whole slide explaining this? – perhaps if you make a very nice diagram Sustainability

Probably remove slide – diagram isn’t useful with time constraint

ColoNet Towards Remote Monitoring Autonomous recharging makes extended-duration tasks possible Need tools to: – Monitor progress – Identify and resolve problems Added bonus – Useful debugging tool User Server TCP/IP Server Wireless R0R0 R1R1 RnRn Sustainability Web client

Future Work Increase task complexity – Coordinated manipulation – Environment exploration Increase trial duration – Days or weeks Increase Colony scale I don’t think you should put SLAM here, it’s very (very x 100) far away from working, and you don’t want to make promises you can’t keep Future Work

Colony Members Duncan Alexander Ben Berkowitz Austin Buchan Brian Coltin Felix Duvallet Siyuan Feng Aaron Johnson Jason Knichel James Kong Christopher Mar Eugene Marinelli Brad Neuman Suresh Nidhiry Justin Scheiner Greg Tress Kevin Woo Cornell Wright Prof. George Kantor

Questions? Can we get an updated picture like this one?