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irobotcreate [2011/02/11 21:43] (current)
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 +===== iRobot Create, Deluxe Edition =====
 +
 +We built a few add-ons for the iRobot Create to allow it be used as a drop-in replacement for more expensive robots in the ROS framework.
 +
 +{{roomba.jpg?300}} {{solidworks_irobot_create.jpg?300}}
 +
 +==== Mechanical ====
 +
 +The iRobot Create has a few mounting holes on the back side of it. I designed a lasercut wooden box that bolts to these holes, and has mount points for the other stuff we need.
 +
 +There are just a few parts to lasercut:
 +
 +{{roomba-box-layout.jpg?400}}
 +
 +The forward-facing webcam mount needs to be fixed (see photo above), but would be easy to do. CAD for Solidworks 2008, as well as a DXF of the layout, are here: {{irobot-create-fitpc2.zip}}.
 +
 +==== Electrical ====
 +
 +I made a silly little PCB which plugs directly into the iRobot Create's DB25 "open interface" connector. It holds a 15-watt +12V DC-DC module and does USB-serial conversion (using the great [[http://ftdichip.com/Products/FT232R.htm|FTDI 232R]] chip). This just saves space and cleans things up a bit.
 +
 +==== Sensing ====
 +
 +(Joint work with Jim Lin.) The idea is for the robot to be cheap. As a result, we are using the [[http://www.hitl.washington.edu/artoolkit/|ARToolKit]] package to recognize fiducials (letter-size printouts of Chinese characters) taped to the ceiling of our lab.
 +
 +However, robots with only ceiling cameras can't sense obstacles until they hit them with their bumpers. So, we are using a two-phase approach: first, a robot equipped with both a ceiling-mounted camera and a laser scanner creates a map of obstacles and walls in the environment, annotated with the positions of the ceiling-mounted fiducials. Then, this map can be used to localize robots equipped only with ceiling-mounted cameras.
 +
 +The lead robot has a Hokuyo [[http://www.hokuyo-aut.jp/02sensor/07scanner/utm_30lx.html|UTM-30LX]] sensor. All robots have one (or two) [[http://www.logitech.com/index.cfm/notebook_products/webcams/devices/5868&cl=us,en|Logitech webcams]]. Those work well under Linux (via the UVC driver) and take decent pictures.
 +
 +==== Computation ====
 +
 +The robot carries around a [[http://fit-pc2.com|Fit-PC2]] computer, which runs the Intel Atom (netbook) processor in a single-board form factor. It runs Ubuntu with no problems. You can buy it from [[http://www.amazon.com/CompuLab-FIT-PC2-Linux-Nettop-PC/dp/B002BUVPWE|Amazon]]; they're $350 or so.
 +
 +==== Software ====
 +
 +  * [[http://ros.org|ROS]]
 +  * [[http://www.hitl.washington.edu/artoolkit/|ARToolKit]]
 +  * A modified version of the ROS/Player AMCL localization module (to appear online soon)