Transcript Slide 1

Vehicle Safety Modifications
Design Review Presentation
May06-21
Client
Senior design
Faculty Advisor
Dr. Gary Tuttle
Team Members
Joshua Bruening EE
Mei-Ling Liew
EE
Fei Liu
EE
Brian Phillips CprE
Adams Sutanto EE
December 8, 2005
Blind Spots
• Driver vision can be restricted by vehicle
architecture, mirror image resolution, the
driver's field of vision, and the driver's
personal mobility, thereby creating blind
spots.
• Vehicle structure and visibility constraints
are two factors that create blind spots and
cause lane change accidents.
Common Mirrors
• Adjusting mirrors correctly
• Minimizing the blind-spots not eliminating
Blind-spot Eliminators
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Improved the driver’s view of what is in front of, to the side of, and behind
the vehicle
Eliminated the potential danger for accidents when entering freeways and
backing up
Solved lane-changing problem
Blind-spot Eliminators
• The blind-spot mirror is an angled add-on
mirror that attaches to an existing side
mirror to increase the blind spot visibility
range by 75% without distortion.
Technology A
• Driver presses a button
• The exterior mirror moves slightly outward,
reflecting the blind spot
• Releases the button, and the mirror
returns to its standard field-of-view.
• Simple and safe
Technology B
• A red LED directional arrow into the mirror
glass.
• Additional warning to traffic when the
driver wants to make lane change.
• Not a distraction when driving at night.
Technology B
• Drivers are not subjected to the full
brightness of the LED technology.
Technology C
• Two digital cameras and advanced computer software
• When another vehicle enters the zone – an area of 9.5
meters by 3.0 meters – a yellow warning light comes on
beside the appropriate door mirror in the driver's
peripheral view
Technology C
• The system will not function in conditions
of poor visibility, for instance in fog or
flying snow
• Too expensive
Technology D
• A single radar sensor on each side of the vehicle
continuously scans the adjacent lane of traffic
from the rear view mirror to about one or more
car length behind the rear bumper.
• Drivers are notified of potential risks by a lighted
icon warning light in the outside rear-view mirror
and can be augmented by an audio tone inside
the vehicle, at the driver's option.
Technology E
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The easy-to-apply lens is 6 "x 8" and designed for the inside of the back
window on SUVs, VANs and MiniVANS, Station Wagons and Trucks with
rear-windowed shells. Made of optical grade PVC (polyvinyl Chloride), it can
be peeled off and re-applied at your discretion.
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The lens is made from a clear, flexible PVC material. The lens is soft and
may be damaged and discolored by harsh cleansers.
A driver's blind spot is that corner of where your peripheral vision is cut off and your
rear view mirror does not spread wide enough to see.
Diagram showing the angle of incidence (i) and angle of reflection (r).
Car manufacturers are required to provide flat, unit magnification mirrors on the driver's side of
the car. Even the inside rear-view mirror also is flat and shows objects without distortion.
• Engineers have found out that the convex side-view mirror on passenger-side affords drivers a
much clearer view of the passenger-side of the car. This is because of the advantage of convex
mirrors - they allow a much wider angle of vision.
• The average radius of curvature not be less than 35" and no greater than 65".
The blind spot eliminator will be a simple 3 inch x 3 inch convex panel mirror added directly on top of the
preexisting side view mirror. The mirror will be paced so that the angle of incidence is set to pick up objects
picked up by the original mirror as well as objects in the preexisting blind spot. The final product will look similar
to the figure below.
Other sensor types considered:
1. Infrared - They can be affected by humidity and water, they can be
expensive and dust and dirt can coat the optics and impair
response. We want sensors that can operate in all
weather.
2. Inductive proximity – They are ideal for virtually all metal sensing
applications, including detecting all metals or nonferrous metals only. We want to detect any type of object.
3. Capacitive proximity – These are used to detect change in the
environment rather than to detect the absolute presence
or
absence of an object. They do not give a direct indication
of
how far away the detected object is.
4. Magnetoresistive – These are the type of sensors found in a metal
detector. We want to detect any type of object.
Fundamental Ultrasonic
Properties
• Ultrasonic sound is a vibration at a frequency above the
range of human hearing, usually >20 kHz. The
microphones and loudspeakers used to receive and
transmit the ultrasonic sound are called transducers.
• Most ultrasonic sensors use a single transducer to both
transmit the sound pulse and receive the reflected echo,
typically operating at frequencies between 40 kHz and
250 kHz.
• A variety of different types of transducers are used in
these systems.
Choosing an Ultrasonic Sensor for Proximity or
Distance Measurement
• Variation in the speed of sound as a function of both temperature and the composition
of the transmission medium, usually air, and how these variations affect sensor
measurement accuracy and resolution
• Variation in the wavelength of sound as a function of both sound speed and
frequency, and how this affects the resolution, accuracy, minimum target size, and the
minimum and maximum target distances of an ultrasonic sensor
• Variation in the attenuation of sound as a function of both frequency and humidity, and
how this affects the maximum target distance for an ultrasonic sensor in air
• Variation of the amplitude of background noise as a function of frequency, and how
this affects the maximum target distance and minimum target size for an ultrasonic
sensor
• Variation in the sound radiation pattern (beam angle) of both the ultrasonic transducer
and the complete sensor system, and how this affects the maximum target distance and
helps eliminate extraneous targets
• Variation in the amplitude of the return echo as a function of the target distance,
geometry, surface, and size, and how this affects the maximum target distance
attainable with an ultrasonic sensor
Background Noise
• The level of background ultrasonic noise
diminishes as the frequency increases.
• The reason is that less noise at the higher
frequencies is produced in the
environment, and the noise that is
produced is greatly attenuated as it travels
through the air.
Target Range Measurement
• For each application, it is important to select a
sensor that will detect the desired targets when
they are located within a specified area in front
of the sensor, but ignore all targets outside this
area.
• A lower frequency sensor should be selected for
longer ranges of detection and a higher
frequency sensor should be used for shorter
range, higher resolution measurements.
• Sensor beam angles should be selected to
cover the desired detection geometry, and to
reject unwanted targets.
*The major benefit of ultrasonic sensors is their ability to measure
difficult targets such as solids, liquids, powders and even transparent
and highly reflective material.
Limitations
• Ultrasonic devices do have some limitations. Foam and other
attenuating surfaces may absorb most of the sound, significantly
decreasing measuring range.
• Extremely rough surfaces may diffuse the sound excessively,
decreasing range and resolution. However, an optimal resolution is
usually guaranteed up to a surface roughness of 0.2 mm.
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Ultrasonic sensors emit a wide sonic cone, limiting their usefulness
for small target measurement and increasing the chance of receiving
feedback from interfering objects.
• Some ultrasonic devices offer a sonic cone angle as narrow as 6º,
permitting detection of much smaller objects and sensing of targets
through narrow spaces such as bottle necks, pipes, and ampoules
Ultrasonic sensors
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A picture of two ultrasonic sensors is shown below:
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Two sensors work in unison, one as the transmitter and one as the receiver. The
transmitter typically sends out a constant beam of sound at a frequency of 40KHz
(note that the human hearing barely goes above 17KHz).
The receiver detects any sounds coming in and gives us a voltage out. So, what
happens is the transmitter sends out a signal. If there isn't an object in front of it,
then the sound wave will carry on (note there is a limit to the distance here!). If, and
only if, there is an object in the way, the sound waves will bounce back along the
same path, and so be picked up by our receiver
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