What's Coming Up: PR2 Calibration

In recent posts, we've showcased the rviz 3-D visualizer and navigation stack, two of the many useful libraries and tools included in the ROS Box Turtle distribution. Now, we'd like to highlight what we're developing for future distribution releases.

The first is the PR2 calibration stack. The PR2 has two pairs of stereo cameras, two forearms cameras, one high-resolution camera, and both a tilting and base laser rangefinder. That's a lot of sensor data to combine with the movement of the robot.

The PR2 calibration stack recently made our lives simpler when updating our plugging-in code.  Eight months ago, without accurate calibration between the PR2 kinematics and sensors, the original plugging-in code applied a brute force spiralling approach to determining an outlet's position. Our new calibration capabilities give the PR2 the new-found ability to plug into an outlet in one go.

The video above shows how we're making calibration a simpler, more automated process for researchers. The PR2 robot can calibrate many of its sensors automatically by moving a small checkerboard through various positions in front of its sensors. You can start the process before lunch, and by the time you get back, there's a nicely calibrated robot ready to go.  We're also working on tools to help researchers understand how well each individual sensor is calibrated.

The PR2 calibration stack is still under active development, but can be used by PR2 robot users with Box Turtle. In the future, we hope this stack will become a mature ROS library capable of supporting a wide variety of hardware platforms.