Robotic Wheelchair
From: NASA Tech Briefs Insider - 10/29/2008

MIT researchers are developing an autonomous wheelchair that can learn all
about the locations in a given building, and then take its occupant to a
given place in response to a verbal command. The wheelchair user would be
able to avoid the need to control every twist and turn of the route and could
sit back and relax as the chair moves from one place to another, based on a
map stored in its memory.  

"It's a system that can learn and adapt to the user," says Nicholas Roy,
assistant professor of aeronautics and astronautics and co-developer of the
wheelchair. "People have different preferences and different ways of
referring to places and objects," he says, and the aim is to have each
wheelchair personalized for its user and the user's environment.  

The robotic wheelchair prototype relies on a Wi-Fi system to make its maps
and then navigate through them, which requires setting up a network of Wi-Fi
nodes around the facility in advance. Outdoors, such a system can rely on a
GPS receiver. In either case, the MIT system can learn about its environment
in much the same way as a person would: By being taken around once on a
guided tour, with important places identified along the way. 

Link:
Robot wheelchair finds its own way
http://web.mit.edu/newsoffice/2008/wheelchair-0919.html
http://web.mit.edu/newsoffice/2008/techtalk53-3.pdf

Developing wheelchair responding to verbal commands
http://www.newsindia-times.com/ArticleText.aspx?article=03_10_2008_011_001&mode=1