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  1. Where's the name Cardea from and who thought of it?
  2. Why three arms?
  3. Why use a Segway RMP?

Q1: Where's the name Cardea from and who thought of it?

A1: Alexander Moore, a UROP with our group (UROP stands for Undergraduate Research Opportunity Program), suggested the name Cardea. He recalled the name Cardea from playing Dungeons and Dragons as a kid. We did a little poking around the web and found that Cardea is the Roman goddess of thresholds and door-pivots and thus a patroness of changes-of-state. Ovid says of Cardea, apparently quoting a religious formula: "Her power is to open what is shut; to shut what is open."|

Here is the clip from our internal web-based bulletin board:

Thread: Reawakening the name debate
Posted by Alex on May 30, 2003 at 10:29:08:
"Coming *very* late to the fray, might I suggest Cardea?
Cardea was a nymph who lived at the site where Rome was founded. The Roman god Janus stumbled upon her and promptly fell in love with her. He gave her power over doorknobs and door handles."

Q2: Why three arms?

A2: Obviously, three arms can do more than two. Imagine needing to hold something that requires two hands while opening a door; three arms would be ideal! Plus there are 3 pairs of arms when one starts with three. On the whole, the goal was to exploit the advantages of humanoid form without being bound to unnecessary restrictions based on the exact form of humans. Thus Cardea won’t have arms that are the same in length, size or end-effectors. Paul Fitzpatrick, a postdoctural lecturer with the group, was the originator of the three arm idea.

Q3: Why use a Segway RMP?

A3: In a nutshell, the RMP can dynamically balance on a small wheelbase that is able to support a torso, arms and “head” at a human scale height. Without dynamic balancing, a two wheeled base would have to be much wider than the typical width of a person’s “footprint”.


PI: Rodney Brooks
MIT Computer Science and Artificial Intelligence Laboratory (CSAIL)
200 Technology Square - MIT Building NE43 - Cambridge, MA 02139 - USA -

(Note: On July 1, 2003, the AI Lab and LCS merged to form CSAIL.)

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