The PR2 robot is a 34 degree of freedom robot designed as part of an open source robotics platform. The head is one of the primary sensor locations, with a sweeping laser range finder on a tilt axis, and a stereo camera able to pan 350° and tilt 115°. Additionally provisions for other, potentially heavy sensors to be mounted were included. To accomplish quick movement of heavy sensors through the range of motion, a special, low backlash drive train was developed, including internal sensing that is able to sense the position of the head to less than 0.01°. 6 Machines was primary designer of the breadboard and alpha prototypes.
Photos from Willow Garage