Massachusetts Institute of Technology researchers have crossed a robotic arm with the bottom half of a Segway to make a robot named Cardea that can traverse hallways and push open doors.
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Cardea consists of the Segway base, sonar sensors that help in navigation, a pair of cameras that form a rudimentary vision system, and a single arm capable of five degrees of freedom -- two at the shoulder, one at the elbow, and two at the wrist. It also has a kickstand.

http://www.ai.mit.edu/projects/cardea - Cardea Homepage

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