Robonaut Head Subsystem
Robonaut's head is still a work in progress, but the existing systemincludes an articulated neck that allows the teleoperator to pointRobonaut's face. The head holds two small color cameras that deliverstereo vision to the operator's helmet display, yielding a form ofdepth perception. The interocular spacing of the cameras is matched totypical human eye spacing, with a fix vergence at arm's reach. Theneck drives are commanded using a 6 axis Polhemus sensor mounted on theteleoperator's helmet, and can track the velocities of typical humanneck motions.
Like the arms, the neck's endoskeleton is covered in a fabric skin,which is fitted into and under the helmet. The helmeted approach isunusual in the robotics world, where cameras are typically mounted inexposed locations on pan-tilt-verge units. Robonaut's requirements fora rugged design, working with astronauts in cluttered environmentsdrove the design towards a better protection system, such as thehelmets that humans where here on Earth. The helmet is made of anepoxy resin, "grown" using a stereo lithography machine at the Johnsonspace center. As you can see, the design was inspired by Centurianarmor, giving Robonaut some attitude.The neck joints are similar to the joints and are controlled withthe same real-time control system. Their kinematics is based on a pan-tilt serial chain, with the first rotation about Robonaut's spine, andthen a pitch motion about a lateral axis. The pitch motion axis doesnot pass through the camera sensors, but is instead 3 inches below, like the Atlas joint in the human neck. This offset (actually aD-H link length) allows the cameras to translate forward, lettingRobonaut see down over its chest.