IR sensors for the Texai, Auto calibration for the PR2

Ze'ev Klapow, our summer intern from Petaluma High School, tackled several challenges to help improve the PR2, Texai, and ROS.

As Texai move into environments outside the Willow Garage offices, it is reasonable to expect that they'll encounter stairs and other potentially hazardous drop-offs. Ze'ev set out to design a low-cost and effective solution to help Texai avoid these hazards. He was able to use multiple, cheap IR sensors -- less than $10 each -- to create an infrared sensor array for the Texai. The prototype uses a ATmega168 microcontroller and three GP2D12/GP2D120 IR rangefinders in a short, medium, and long-range configuration, in order to slow the robot before approaching a drop-off and stop it if gets too close.

Ze'ev also worked on automating more of the PR2 calibration process. PR2 already automates some of its own calibration, including waving a small checkerboard in front of its sensors. However, there are steps that required the help of a person, such as waving a larger checkerboard around for the wide stereo cameras and moving a small checkerboard from the left gripper to the right. With the new "auto calibration" code, the process is now just setup and go. PR2 drives around the large checkerboard on its own and is able to move the small checkerboard from one gripper to the other.

Another project that Ze'ev worked on was making it easier to setup ROS packages with XCode and Cocoa on OS X. You can find more information here.