Robotic Wheelchair from Chiba Tech Turns Wheels into Legs and Climbs over
  Steps
From: Evaluation Engineering
By: Don Kennedy and Ryo Osuga

At the Chiba Institute of Technology, a group led by Shuro Nakajima has
developed a robot wheelchair that can climb over steps.

This robot can make a variety of movements, using its four-wheel drive and
five axes. Normally, it rolls along on its wheels, but if there's a step or
ditch, it can get over the obstacle by using its wheels as legs. All the user
needs to do is tell it which direction to go, using a joystick. The robot
automatically assesses the surrounding terrain and moves appropriately.

Read the entire article and view a video (2:41) at:
http://www.diginfo.tv/v/12-0174-r-en.php

Links:
Japanese engineer creates wheelchair that can walk up stairs (with video 1:38)
http://www.rawstory.com/rs/2012/10/23/japanese-engineer-creates-wheelchair-that-can-walk-up-stairs/

Robot wheelchair that can climb stairs and descend steep terrain
http://www.damngeeky.com/2012/10/16/6251/robot-wheelchair-that-can-climb-stairs-and-descend-steep-terrain.html#more