Transcript View - Carnegie Mellon Robotics Club

Towards an Autonomously Recharging Robot Colony
Duncan Alexander
Christopher Mar
Austin Buchan
Eugene Marinelli
Brian Coltin
Bradford Neuman
Robot Platform
Felix Duvallet
Siyuan Feng
Suresh Nidhiry
Justin Scheiner
Advisor: George Kantor
Jason Knichel
Gregory Tress
James Kong
Kevin Woo
Autonomous Recharging
Dragonfly
Abstract
Charging Station
Docking Bays
At the foundation of each Colony robot
is the Dragonfly circuit board.
Power management is becoming an increasingly important area in
mobile robotics. In groups of robots, power concerns are compounded
by a large number of agents sharing limited resources, requiring
methods for power management. We have developed specialized
hardware and algorithms that allow our colony of robots to
autonomously locate and dock with a charging station and recharge
their batteries. Using only simple locomotion, limited sensing and
onboard processing capabilities, we have demonstrated autonomous
recharging for a group of small low-cost robots. These advances will
allow the Colony to operate over extended periods of time and perform
tasks without the need for human intervention.
The Charging Station manages docking
requests and allocates docking bays
Docking bays guide in robots and
supply power for battery charging.
Features:
• ATMega128 microcontroller
• XBee wireless module
• Manages up to 8 docking bays
Features:
• Linear BOM
• Homing Beacon
• Charging Contacts
Features:
• ATMega128 microcontroller
• XBee wireless module
• USB interface
• 5 Sharp IR rangefinders
• 2 Tri-color LEDs
• Support for encoders and servos
Dragonfly
BOM
ARCHS Board
Charge Contacts
Homing Sensor
BOM Sensor
Colony robots use the BOM (Bearing
and Orientation Module) to locate other
robots and charging stations.
• Coplanar ring of IR
LEDs and IR detectors
• Provides localization
data
Overview of the
Autonomous
Recharging System
Robot 2
Robot 1
Wireless Token
Ring
ARCHS Charging Board
Charging
Algorithm
ARCHS (Autonomous ReCharging and Homing System) is a separate circuit
board that facilitates the recharging process. ARCHS relays homing data to the
Dragonfly and regulates battery recharging.
Features:
• ATTiny861 microcontroller
• Homing Sensor
• Charge contact sensing
• Charging current regulator
• Temperature and voltage monitoring
• Inter-Integrated Circuit Protocol (I2C)
communication
Dragonfly
Scheduler:
Task and
Charging
FSMs
Docking Bays
BOM and Homing Signals
Charge
Request
Charging Station
Charge
Accept/Deny
Homing Beacon
Emitters
Charging Contacts
Recharging Process
…
I 2C
Linear BOM Segment
Robot 4
Robot 3
Robot 0
Charge Board
Control Circuitry
Bay Allocation Manager
1. Robot detects low battery
2. Robot requests a bay from the
charging station over wireless
3. Charging station accepts or
denies the request
• Bay allocation algorithm assigns
bay based on availability
4. Robot moves towards the bay
• BOM sensor guidance until
homing signal is detected
• Homing sensor guidance for finetuned docking movement
5. Regulated battery charging
• ARCHS monitors the temperature
and voltage of the battery
• Robot signaled when charge is
complete
6. Robot leaves the docking bay and
continues its task
Behaviors
•
•
•
•
•
ColoNet
ColoNet Overview
An Internet interface between the Colony and the world.
Features:
• Remote control and monitoring of the Colony
over the Internet
• Manual control of individual robots or the entire colony
• Global Colony task queuing
• Monitoring and recording of wireless communications
• Web-based Java GUI
ColoNet Interconnections
• Multiple clients
connect to the
TCP/IP
server via TCP/IP
Client
• Server parses
information from
clients
• Server relays data over
wireless to and from the robots
Behaviors written as tasks using finite state machines (FSM) to control execution
Tasks include activities such as avoiding obstacles, seeking light, solving mazes
Tasks run normally until a low battery is detected
Program switches to the Charging FSM to handle autonomous recharging
Charging FSM
• Handles wireless communication with the charging station and I2C
communication with the ARCHS charging board
• Controls docking and departing movement
• Relinquishes control to task FSM once recharging process is complete
Acknowledgments
Wireless
Server
Robots
We first would like to thank our advisor George Kantor. We would also like to thank
Howie Choset and Peggy Martin for their help and support, as well as Brian Kirby, Tom
Lauwers, Prasanna Velagapudi, Steven Shamlian, and Cornell Wright for their
contributions to the project.
This project was funded in part by Carnegie Mellon’s Undergraduate Office. The
results represent the views of the authors and not those of Carnegie Mellon University.