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5 CONCLUSIONS
This paper presented the implementation of a robotic
Intelligent Wheelchair, simulating its behavior in an
adapted Cyber-Mouse simulator. This agent resulted
of a modular system composed of three modules.
The first one is a shared control that merges user
commands with the information received by the IW
sensors. This advantage prevents the collision with
objects in its way becoming movement system more
reliable and safe. The algorithms developed use a
subsumption architecture: once there are objects
close to the wheelchair, the user commands are
disabled and deflect commands are sent to the
motors, ensuring a safe motion.
A module was develop using the A* algorithm as
path generator to calculate the shortest path from the
robot’s actual position to the objective point. The
third module was implemented to plan some usual
tasks in a hospital environment, using Strips
planning to solve these interactions. In most of the
cases Strips proved to be efficient, delivering
complete plans, with exceptions presented under
Sussman anomaly effects, where one operation
cancels other in the plan.
It was also demonstrated that Cyber-Mouse is a
friendly tool to test control algorithms, IW
navigation and its interaction with hospital
environment.
Future research directions include the
improvement to non-linear planning and upgrade
from A* to D* algorithm, once it’s preferable in
such a dynamic environment. To be fully intelligent,
it’s not enough the wheelchair to plan its own path
or share its control. It is also necessary to
communicate with other intelligent wheelchairs and
devices like doors activation systems, elevators and
lights. Due to this, it is intended to perform an in
depth study in proper methodologies to implement
these capacities in the wheelchair, and this way,
implement some functions as cooperative behavior
among a group of IW and collaboration among the
user and the system. In Cyber-Mouse it is necessary
to increase its present simulation capacities, from its
actual three IW, enabling hybrid systems test, where
real and virtual IW interact with each other. These
interactions make possible high complexity tests
with a substantial number of devices and
wheelchairs, representing a reduction in the project
costs, once there wouldn’t be necessary a large
number of real IW. Still, in Cyber-Mouse, it is
necessary to implement noise treatment in the
motors and sensors to have actions in the simulated
wheelchair closer to those of real wheelchairs.
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