  To date, self-driving experimental wheelchair technologies have been either
inexpensive or robust, but not both. Yet, in order to achieve real-world
acceptance, both qualities are fundamentally essential. We present a unique
approach to achieve inexpensive and robust autonomous and semi-autonomous
assistive navigation for existing fielded wheelchairs, of which there are
approximately 5 million units in Canada and United States alone. Our prototype
wheelchair platform is capable of localization and mapping, as well as robust
obstacle avoidance, using only a commodity RGB-D sensor and wheel odometry. As
a specific example of the navigation capabilities, we focus on the single most
common navigation problem: the traversal of narrow doorways in arbitrary
environments. The software we have developed is generalizable to corridor
following, desk docking, and other navigation tasks that are either extremely
difficult or impossible for people with upper-body mobility impairments.
