Abstract
An assistive robotic wheelchair system should allow its
user to travel more efficiently and with greater ease.
While standard electric wheelchairs can be used by people
with limited upper body mobility, some tasks such as
door opening and moving around corners require fine
joystick control that these users often find difficult. This
paper reports initial work in the development of a semiautonomous
robotic wheelchair system. The robotic
wheelchair system described in this paper, Wheelesley,
automates many common navigational tasks for the user.
The system consists of a standard electric wheelchair with
an on-board computer, sensors and a graphical user
interface running on a mounted notebook computer.
Introduction
Assistive robotics can improve the quality of life for
disabled people. This project aims to develop a robotic
wheelchair system that will assist its user with
navigational tasks while supplying information about the
world to the user. Electric wheelchairs can be used by
people with limited upper body mobility through joystick
control. However, the joystick requires fine control that
the person may have difficulty accomplishing. Our
system allows the user to tell the robot where to move in
gross terms and will then carry out that navigational task
using common sensical constraints such as avoiding
collisions. For example, it may be easy for a disabled person
to gesture in the direction of a doorway, but it may be
difficult for that person to do the fine navigation required
to direct the wheelchair through a doorway that is barely
wider than the wheelchair. To move through a doorway
using our system, the user will tell the robot that there is
a doorway ahead using our graphical user interface. The
robot will then move through the doorway for the user.
Our robotic wheelchair system is intended to be a
general purpose navigational assistant in environments
with accessible features such as ramps and doorways of
sufficient width to allow a wheelchair to pass. We will
not rely on maps for our navigation, which will allow the
wheelchair system to be used in any accessible building.
We believe that a robotic wheelchair system should not be
limited to one particular location, either by requiring maps
or by environment modification. The current focus of the
research is indoor navigation, but we are also developing
navigational assistance for outdoor use. The tasks of the
wheelchair include navigating down busy corridors,
moving through doorways, pulling up to desks and tables,
and moving up and down ramps.
This work is based on previous research in robot
path planning and mobile robotics. The primary focus of
mobile robotics research is autonomy. However, a
robotic wheelchair must interact with its user, making the
robotic system semi-autonomous rather than completely
autonomous. A mobile robot is often only given its
goal destination and a map. The wheelchair can not
subscribe to this method. The user may decide to change
course during traversal of the path -- as he starts to go by
the library on the way to the mail room, he decides to
stop at the library to look for a book he needs.

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