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RFID-and-GPS-Integrated-Navigation-System
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（完整内容请下载后查看）RFID and GPS Integrated Navigation System
for the Visually Impaired
Kumar Yelamarthi, Daniel Haas, Daniel Nielsen, Shawn Mothersell
School of Engineering and Technology
Central Michigan University
Mt Pleasant, MI 48859
Email:
additional cost of a guide dog. Even after training and
implementation costs, a guide dog can provide only limited
assistance.
Abstract—ꢀThis paper describes an RFID and GPS integrated
navigation system, Smart-Robot (SR) for the visually impaired.
The SR uses RFID and GPS based localization while operating
indoor and outdoor respectively. The portable terminal unit is
an embedded system equipped with an RFID reader, GPS, and
analog compass as input devices to obtain location and
orientation. The SR can guide the user to a predefined
destination, or create a new route on-the-fly for later use. While
in navigation mode, the SR reaches the destination by avoiding
Navigation in unfamiliar spaces is a problem for the
visually impaired [7], but learning is relatively rapid. So
applications that support navigation in unfamiliar places are
very helpful for the visually impaired [8]. Integration of
current technology such as position recognition, obstacle
obstacles using ultrasonic and infrared sensor inputs. The SR detection, and embedded systems accommodates the design of
also provides user feedback through a speaker, and vibrating
motors on the glove. The SR prototype has been successfully
implemented and is operational.
a navigation system to help the visually impaired navigate
easily.
This paper presents the design and implementation of a
Radio Frequency Identification (RFID) and Global Positioning
System (GPS) integrated navigation system; Smart-Robot
(SR) to operate in both familiar and new environments. This
navigation system helps the visually impaired people solve
many problems such as, leaving home by themselves in a safe
and convenient way, participate in more social and civic
activities to improve their quality of life. At the same time, the
reliable aid system for the visually impaired represents a
civilized, harmonious, progressive society, and a service-
oriented project for the engineers [9].
I.
INTRODUCTION
The National Center for Health Statistics states that
approximately 1.3 million people in the United States are
visually impaired [1]. The following specifics put the visually
impaired person dilemma into perspective and the challenges
faced in the United States [2] alone: (1) Number of working
age blind who are unemployed: 74% [3]; (2) Estimated annual
cost of blindness to the US government: $4 billion [4]; (3)
Lifetime cost of support and unpaid taxes for one blind
person: $916,000 [5].
II. PREVIOUS WORK
Given the persistence of gaps, it is not surprising that
engineers can help the visually impaired person in their daily
activities such as commuting. A visually impaired person in
most cases uses a white cane to navigate and find the way.
This traditional method is passive in that they must find their
way using marking. If they fail to find the appropriate
marking, they may face some problems. Also, in situations
where this person has sensory organ problems or in
emergencies, this is not a reliable method. An active
navigation method with appropriate feedback to the user may
be helpful for the visually impaired. Some visually impaired
people use guide dog as an alternative. However, the dog must
be trained for at least two years and the cost of training
$38,000 is too high for many [6]. The American Foundation
for the Blind states that over half of the legally blind people in
the United States are unemployed, relying on their families for
financial assistance [1]. Many families cannot afford the
Over the past three decades, research has been conducted
to design new navigation devices for the visually impaired.
Benjamin et al. [10] built a laser cane that uses optical
triangulation with three laser diodes. The first laser points at
the ground detecting a drop in elevation, the second points
straight in front of the user parallel to the ground, and the third
points straight ahead at an angle of 45o from the ground to
protect the user from overhanging obstacles. Bissit and Heyes
[11] developed a hand-held sonar device that gives the user
auditory feedback with eight discrete levels. Shoval et. al [12]
developed the Belt, an obstacle avoidance wearable computer
for indoor navigation. Na [13] proposed an interactive guide
system for indoor positioning, and Farrah [14] proposed the
virtual reality technology to capture images of the house using
cameras, and uses this information for indoors navigation.
Kulyukin [15] proposed a closely related work, the robot-
assisted navigation method for indoor environments.
978-1-4244-7773-9/10/$26.00 ©2010 IEEE
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While these devices have shown promise, they have microcontroller. Indoor navigation is performed using a
several limitations. The laser cane provides no navigational SkyeTek DKM9 RFID system, and outdoor navigation is
assistance; a tone is triggered to indicate a drop off even for a performed using a Garmin OEM 18x GPS. A simple 4x4 hex
small change in ground level (example: puddle); difference in keypad is used to enter to the destination information.
the cane orientation with respect of the ground changes the Obstacle detection is performed using two Sharp GP2D12
direction of the lasers causing false audio cues etc. The hand- infrared (IR) sensors and one MAXBotix MaxSonar EZ0
held sonar device does not provide navigation assistance, and ultrasonic sensor. Also, a Robson 1655 analog compass is
cannot detect drop-offs such as curbs, steps etc. The used to keep track of SR’s movement during obstacle
interactive guide system proposed by Na [13] works only
indoors and does not detect obstacles in the travel path. The
virtual reality technology proposed by Farrah [14] requires
extensive image processing capabilities, and does not work in
new or busy outdoor environments. The robot-assisted
navigation by Kulyukin et al. [15] is closely related to our
work, but has limitations such as: works only in structured
indoor environments, and uses expensive lasers to classify the
environment into cells of free space for navigation.
avoidance maneuvers.
The Smart-Robot entails two feedback signals, one from a
small speaker, and the other from a glove with 10-mm shaft-
less vibration motors on the index, middle and ring fingers.
These vibration motors are included to increase the reliability
of feedback signals in noisy environment, and to
accommodate for users with audio sensory impairment. The
GPS antenna, RFID antenna, and the three obstacle detection
sensors (ultrasonic and infrared) are mounted outside the
Also, many of these existing systems increase the user’s chassis, and other hardware including the battery is enclosed
navigation-related physical load, as they require the user to
wear additional body gear [12], contributing to physical
fatigue. Based on the principles of universal design [16], the
navigation systems for the blind should encompass design
characteristics such as: equitable use, flexibility, simple and
intuitive, perceptible information, tolerance for error, low
physical efforts, size and space for approach and use, and
acceptable process. In accordance with these guidelines, this
paper presents the Smart-Robot, a RFID and GPS integrated
navigation system for the visually impaired.
inside the chassis as in Fig 2.
As all the components of SR require different voltage
levels, ranging from 3.3 to 12 volts, a power bus has been
designed as in Fig 3. The GPS, Ultrasonic sensors, IR sensors,
and RFID operate at 5 volts. As the high frequency RFID
system consumes a relatively large amount of current, an
independent voltage regulator and fuse have been used. The
DC motors, microcontroller and vibration motors all operate at
12, 9 and 3.3 volts respectively. Polymeric Temperature
Coefficient (PTC) resettable fuses have been used throughout
to prevent design failure. A switch in the power bus will allow
the user to turn the SR on and off.
III. SMART-ROBOT DESIGN IMPLEMENTATION
The Smart-Robot is classified into input module and output
module as shown in Fig 1. The input module comprises of
user input device, obstacle detection sensors, and navigation
and orientation unit. The output module comprises of user
feedback devices, the SR motors for movement, display screen
for troubleshooting, and a data storage unit. Both these
The components of SR have a combined maximum current
consumption of 3A. However, rarely will the device require
maximum power. Based on this assumption and heuristic
analysis, the SR uses a 6600 mAH 14.8 V Lithium ion battery
sufficient to allow the user commute for at least three hours on
a single charge.
modules are interfaced using
a
Motorola 68HCS12
Figure 1: Block Diagram of Smart-Robot
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If the user intends to use a predefined route, the system
will ask for route origin and destination. Upon input from the
user, the system will fetch the route coordinates from the
appropriate route file, and load them on a route array “ra =
{i,i+1,…..,k}”. Next, the system obtains the current longitude
and latitude coordinates ‘x’ from the GPS/RFID, and
computes the distance and direction from ‘x’ to the next
landmark ‘i’. Upon computation of these parameters, the
microcontroller sends appropriate signals to the robot motors
for navigation.
While in operation, the SR continuously checks for
obstacles using the ultrasonic and infrared sensors mounted on
the top of design chassis. The ultrasonic sensor detects
obstacles relatively straight ahead while the two infrared
sensors detect obstacles at a 22.5o angle relative to the front of
the robot. To avoid an obstacle, the SR uses inputs from all
three sensors. Upon identifying any obstacle in its path, the SR
computes a new route to avoid obstacles, and overwrites the
route array ‘ra’. If only the ultrasonic sensor detects an
obstacle, the SR would have to turn left or right appropriately
and continue until the opposite infrared sensor clears the
object. If only one infrared sensor detects an obstruction, the
distance is calculated relative to the robot, and a new routing
coordinates are calculated and overwritten on the route array
‘ra’. The output of each sensor with respect to its distance is
shown in Fig 5.
Figure 2: Smart-Robot Chassis
With primary constraints of the SR design being simple
and cost effective, off-the-shelf components have been used
through the design. While operating outdoors, the GPS
accuracy of ≤2m is high enough to keep the user on the
sidewalk. When the user enters a building, the RFID system
will activate to guide the user to appropriate destination.
While indoors, the SR always moves close to the right wall for
better RFID signal reception. Accordingly, the user can
successfully use the SR to navigate safely both indoors and
outdoors.
During travel, the SR provides continuous feedback to the
user through the speaker and vibrating motors on the glove.
When the SR is about to turn left or right, the motors present
on the index finger and ring finger of the glove vibrate to
inform the user of appropriate movement. Upon reaching each
landmark, the speaker announces the appropriate location
information.
IV. SMART-ROBOT OPERATION
The navigation algorithm for the Smart-Robot is shown in
Fig 4. Operation of the SR starts by turning on the master
power switch that supplies energy to the power regulator
board as in Fig 3. After the device has been powered on, the
system will beep and vibrate all finger motors to notify the
user that the device is ready for navigation assistance.
Through the speaker, the system will ask if the user intends to
use a predefined route, or create a new route.
Figure 4: Navigation Algorithm of Smart-Robot
Figure 3: Power-bus Schematic
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currently in progress to reduce this variation in travel time by
developing effective localization algorithms.
VI. CONCLUSION
The concept of utilizing RFID and GPS for navigation
assistance to the visually impaired is both technically and
economically feasible. The barrier to entry for this technology
is low after efficient RFID and GPS localization algorithms
are developed. This Smart-Robot system helps the visually
impaired person become less dependent on others to commute,
and shows promising incentive in improving the quality of
life. Overall, the Smart-Robot could make these routine tasks
simple and feasible for a visually impaired person.
Figure 5: Obstacle Detection Range
REFERENCES
[1] Facts and Figures on Americans with Vision Loss, American
Foundation for the Blind, New York, NY. 2008.
If the user intends to create a new route, the system will
ask the user for route origin and destination. Accordingly, the
direction buttons (left, right, forward, and backwards) will be
activated. Later, the user can use these buttons to move the SR
to the appropriate destination. Throughout the duration of this
travel, the system will record the longitude and latitude
coordinates periodically from the RFID while indoors, or from
the GPS while outdoors and store them in a route array “ra =
{i,i+1,…..,k}”. Upon reaching the destination, the user presses
the “#” button to indicate the destination. Accordingly, the
route array ‘ra’ will be saved into an appropriate route file in
the system memory. The route file is then closed and the
system returns to the start sequence.
[2] S. Willis, S. Helal, “RFID information grid for blind navigation and
wayfinding,” Proceedings of IEEE International Symposium on
Wearable Computers, Dec 2005.
[3] Kirchner and Schneidler, Journal of Visual Impairement and Blindness,
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[4] Prevent
Blindness
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Internet:
[5] Figured using SSI& SSDI average payments and unpaid tax estimates.
[6] Guide Dogs, Internet: http://www.guidedogsofamerica.org/faq.html,
Guide Dogs of America, Sylmar, CA. 2009
[7] D. Baldwin, “Wayfinding technology: A road map to the future,”
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the visually impaired using RFID technology”, Proceedings of Health
Informatics New Zealand Annual Conference and Exhibition, Oct
2008.
V. PILOT EXPERIMENTS
The Smart-Robot is a work-in-progress and has yet to be
tested extensively. To test the system’s ability in addressing
the user’s needs, the design team has created appropriate
[9] B. Ding, H. Yuan, L. Jiang, X. Zang, “The research on blind navigation
system based on RFID,” Proceedings of International Conference on
Wireless Communications, Networking, and Computing, Sep 2007.
experiments to quantify the performance of SR under a [10] J. M, Benjamin, N. A. Ali, and A. F. Schepis, “A laser cane for the
blind,” Proceedings of San Diego Medical Symposium, 1973.
controlled environment. Data was collected and analyzed to
validate the reliability of implementing the SR.
[11] D. Bissit, A. Heyes, “An application of biofeedback in the
rehabilitation of the blind,” Applied Ergonomics, vol. 11, no.1, pp.31-
33, 1980.
The pilot experiments focused on reaching destination
[12] S. Shoval, J. Borenstein, Y. Koren, “Mobile robot obstacle avoidance in
with minimum input from the user. The SR was deployed for
operation between three buildings on the university campus.
Thirty RFID tags were placed outside the walls of a few
a computerized travel aid for the blind,” Proceedings of the IEEE
International Conference on Robotics and Automation, May 1994.
[13] J. Na, “The blind interactive guide system using RFID-based indoor
rooms in each building using small pieces of cardboard to
insulate from metal or dirt. Information from these RFID tags
is used as landmarks indoor, and GPS coordinates are used
for landmarks outdoor.
positioning system,” Lecture Notes in Computer Science, Springer
Publications, vol. 4061, pp. 1298-1305, 2006.
[14] W. Farrah, R. Nagarajan, Y. Sazali, “Application of stereovision in a
navigation aid for the blind people,” Proceedings of ICICS-PCM 2003,
Dec 2003.
Three different routes were created and recorded on the [15] V. Kuljukin, C. Gharpure, J. Nicholson, G. Osborne, “Robot-assisted
wayfinding for the visually impaired in structured indoor
environments,” Autonomous Robots, vol. 21, no.1, pp: 29-41, 2006.
system using the algorithm presented in Fig. 4. The design
team tested these routes four times with low traffic indoors
and outdoors. It was observed that SR reaches the destination
with slight variation in travel time. This is due to limited
[16] The Center for Universal Design, “The principles of universal design,”
North Carolina State University.
accuracy (≈2m) of the GPS, and RFID system. Research is
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