James, Kurian; Dr.Saseendran Pillai,P R(Cochin University of Science & Technology, October , 2008)
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Abstract:
ACCURATE sensing of vehicle position and attitude is still a very challenging
problem in many mobile robot applications. The mobile robot vehicle applications
must have some means of estimating where they are and in which direction they are
heading. Many existing indoor positioning systems are limited in workspace and
robustness because they require clear lines-of-sight or do not provide absolute, driftfree
measurements.The research work presented in this dissertation provides a new approach to
position and attitude sensing system designed specifically to meet the challenges of
operation in a realistic, cluttered indoor environment, such as that of an office
building, hospital, industrial or warehouse. This is accomplished by an innovative
assembly of infrared LED source that restricts the spreading of the light intensity
distribution confined to a sheet of light and is encoded with localization and traffic
information. This Digital Infrared Sheet of Light Beacon (DISLiB) developed for
mobile robot is a high resolution absolute localization system which is simple, fast,
accurate and robust, without much of computational burden or significant processing.
Most of the available beacon's performance in corridors and narrow passages are not
satisfactory, whereas the performance of DISLiB is very encouraging in such
situations. This research overcomes most of the inherent limitations of existing
systems.The work further examines the odometric localization errors caused by over
count readings of an optical encoder based odometric system in a mobile robot due to
wheel-slippage and terrain irregularities. A simple and efficient method is investigated and realized using an FPGA for reducing the errors. The detection and correction is
based on redundant encoder measurements. The method suggested relies on the fact
that the wheel slippage or terrain irregularities cause more count readings from the
encoder than what corresponds to the actual distance travelled by the vehicle.The application of encoded Digital Infrared Sheet of Light Beacon (DISLiB)
system can be extended to intelligent control of the public transportation system. The
system is capable of receiving traffic status input through a GSM (Global System
Mobile) modem. The vehicles have infrared receivers and processors capable of
decoding the information, and generating the audio and video messages to assist the
driver. The thesis further examines the usefulness of the technique to assist the
movement of differently-able (blind) persons in indoor or outdoor premises of his
residence.The work addressed in this thesis suggests a new way forward in the
development of autonomous robotics and guidance systems. However, this work can
be easily extended to many other challenging domains, as well.
Description:
Department of Electronics,
Cochin University of Science and Technology