Assistive Mobile Manipulation for Self-Care Tasks Around the Head

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Date
2014Author
Hawkins, Kelsey P.
Grice, Phillip M.
Chen, Tiffany L.
King, Chih-Hung
Kemp, Charles C.
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Show full item recordAbstract
Human-scale mobile robots with arms have the
potential to assist people with a variety of tasks. We present
a proof-of-concept system that has enabled a person with
severe quadriplegia named Henry Evans to shave himself in his
own home using a general purpose mobile manipulator (PR2
from Willow Garage). The robot primarily provides assistance
by holding a tool (e.g., an electric shaver) at user-specified
locations around the user’s head, while he/she moves his/her
head against it. If the robot detects forces inappropriate for
the task (e.g., shaving), it withdraws the tool. The robot also
holds a mirror with its other arm, so that the user can see
what he/she is doing. For all aspects of the task, the robot and
the human work together. The robot uses a series of distinct
semi-autonomous subsystems during the task to navigate to
poses next to the wheelchair, attain initial arm configurations,
register a 3D model of the person’s head, move the tool
to coarse semantically-labeled tool poses (e.g, “Cheek”), and
finely position the tool via incremental movements. Notably,
while moving the tool near the user’s head, the robot uses an
ellipsoidal coordinate system attached to the 3D head model. In
addition to describing the complete robotic system, we report
results from Henry Evans using it to shave both sides of his face
while sitting in his wheelchair at home. He found the process to
be long (54 minutes) and the interface unintuitive. Yet, he also
found the system to be comfortable to use, felt safe while using
it, was satisfied with it, and preferred it to a human caregiver.