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FIELD JOURNAL
Robonaut - He's the man by Lori Keith
July 30, 2000 I hope you all are having a great summer. I have been busy doing many things. I just got back from a week in Panama City Beach, Florida, for vacation. It was so pretty there, especially about ten miles in from the beach. I now know where I want to retire to, in about 30 or 40 years :-) . Besides trying to touch base with all of STO's JSC experts, I have also spent time supporting an online robotics course presented by NASA and the University of North Dakota. I assisted with chat moderation. For this project, I read aloud questions sent in by students during class time. (These classes were broadcast live on the Internet.) These questions were then answered during the class time, which made the online course interactive. Of course, I had to decide which questions that came in were relevant for the time that we had online, as we only had two hours each session. Some questions and comments were reserved for the expert presenter to answer or comment on offline. Because I actually attended these sessions, I learned a bit about robotics and I thought I'd share it with you. I found most of the sessions to be quite interesting.
The wrist has 2 DOF; the hand has 12 DOF, and 5-pound fingertip strength -- allowing for finger joint position control and finger tip force control. These attributes become important when using certain tools, like drills, etc. It also allows Robonaut to be able to pick up small objects, like a washer, with a pair of tweezers. It is powerful enough to lift a 21-pound weight on the Earth's surface giving it considerable capabilities in a zero-G environment. The hand and forearm weigh about six pounds. In the 8-inch forearm are 14 electric motors, 13 circuit boards, 12 five-element drive trains for the fingers, two two-element drives for the wrist, 42 base-level sensors which provide information on the position and velocity of each actuator. Tactile sensors, which will allow the hand operator a degree of feeling, will be added soon. The hand has 12 DOF - one 3 DOF in the thumb, two 3 DOF primary fingers, two 1 DOF gripping fingers and one palm degree of freedom. This makes Robonaut's hand a remarkable wonder with what it is capable of doing, and how it is capable of emulating a human hand. The first two fingers and the thumb make up the dexterous work side. They have three degrees of freedom -- they can open and close as well as spread apart, essentially like human fingers. The remaining two fingers only open and close, and are used for grasping. The palm can cup to help grasp tools, too. It had to be functional enough to work with a variety of tools and other devices. It had to be rugged enough to survive the space environment. It had to be extremely compact, much like a human hand, wrist and arm.
  NASA's Automation, Robotics & Simulation Division (AR&SD) is developing a way to operate Robonaut, called telepresence. Telepresence uses virtual reality display technology to visually take the operator into the robot's workspace. This is done using images captured from cameras positioned in the robot. This way the teleoperator feels as if he or she is in the place of the robot. The teleoperator's head and arm movements will make Robonaut's head and arms move. Visual feedback will be provided by a stereo display helmet and will include live video, from the robot's head cameras. Gloves with finger sensors will provide the feedback for the arm, hand and finger movements. The operator would then perform the arm, head and hand motions for the required tasks and Robonaut duplicates the same motions. This becomes important because Robonaut will be able to do some of the more dangerous jobs, allowing the astronauts to be in a safer environment. Robonaut is a pretty big deal, and is also quite new to the NASA scene. His big debut was June 8, here at the Johnson Space Center.
Neat sites to visit for more information on Robonaut and its technology:RobonautCNN.com - Space - Robonaut prepares for spacewalking duties |
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One
of the coolest sessions was about Robonaut. Robonaut is a robot designed
for working in space. Dr. Ron Diftler, who works for Lockheed Martin,
here at JSC, gave the presentation. Dr. Diftler, with Lockheed Martin's
Automation and Robotics Department, worked on the development of the wrist
and forearm packaging. The neat thing about Robonaut is that it has a
hand with moving capabilities similar to a human. As humans, our bodies
can move in degrees of freedom (DOF) -- 80 joints (including the fingers)
with a total of 135 degrees of freedom. A degree of freedom is equal to
each individual controlled motion, measured as translational degrees of
freedom x, y, z; as well as three rotational degrees of freedom, or rotation
around the axes x, y and z. (For more on the technical aspects, you can
visit some of the links listed below.) Though not nearly on a human scale,
this robot has 7 DOF in its arms, 5 fingered dexterous hands, 2 DOF in
the neck, and 3 DOF in the waist. 
