Note: Descriptions are shown in the official language in which they were submitted.
CA 02482691 2004-11-03
SURFACE MATERIAL AND CONDITION SENSING SYSTEM
This application is a. divisional of Canadian
Patent Application 2,233,689 filed October 4, 1996.
. BACKGROUND OF T~iE INVENTION
Field of the Invention
This invention generally relates to vehicle
mounted sensor systems and more particillarly to a
system for determining characteristics of surface
material related to adverse driving conditions from
a vehicle. w
Description of Related Art
A number of attempts have been made to sense
the conditions of raadways, aircraft runways, and,
other surfaces for vehicular: traffic, during
changing adverse weather conditions. For example,
it is known to place conductivity, temperature and
other sensors either in the road surface or adjacent
" 25 the road to monitor the temperature of the road
surface andjar monitor whether there is ice forming
on the surface. This information is fed to the
center for control. and disp<~.tch of trucks to apply .
salt or sand or other deicing mixtures. At airports
these types of warning systems are used to inform
maintenance crews~that the :runways need to be
treated or alert the staff that deicing procedures
need to be implemented. Some canventional systems
have a supply of chemicals and pumps beside the
roadway to automatically spray the road when
triggered by a sensor.
There is also a need for such a warning system
CA 02482691 2004-11-03
2
on road vehicles such as cars and trucks to detect
pending adverse conditions. However,. available
mobile systems are limited to basic moisture
detection and temperature monitoring systems. Some
examples of such systems are disclosed in U.S.
Patent Nos. 4,492,952 and 4,78,056. One particular
system, disclosed in U.S. Patent No. 5;416,476,
employs an infrared sensor which is mounted on the
exterior of the vehicle and sends a signal to a
microprocessor which then can display the
temperature of the road surface. These systems are
simplistic and do not tell the operator the critical
information needed under all conditions, such as, at
what temperature will the particular material
actually on the road surface freeze? Therefore
there is a need for a material sensing apparatus and
system far determining when an actual liquid on a
road surface will freeze and alerting the operator
to such situations before they actually occur so
that the operator can adjust driving techniques
accordingly.
There is also a need for a mobile mounted
sensing apparatus and system for use by road crews
'"' ~ t.o evaluate existing material. on a road surface in
order to determine the amount of additional material
to be applied to the surface in order to reduce the
hazardous driving conditions.
SL7NI~IARY OF THEM TNVENTION
The system in accordance with the present
invention addresses the above described needs. It
is thus an object of the present invention to
provide a unique multipurpase system which includes
a multipurpose sensor mounting platform
accommodating a variety of sensors that enables the
temporary use of materials such as rainwater and
CA 02482691 2004-11-03
3
road conditioning materials actually encountered on a road
surface to determine the condition of t:he road surface. It
is another object of the invention to ~>rovide a system for
detecting the actual materials on a roadway. It is another
object of the invention to provide a system for determining
a characteristic such as friction coefficients or the
actual freezing temperature of a material on a road surface
regardless of the makeup of the material. It is a still
further object of the present invention to provide a
reliable display of information .to the vehicle operator of
actual and pending conditions of the road surface. It is a
still further object of the invention to provide an
apparatus for sensing actual road conditions that can
function automatically or manually.
In one aspect the invention provides a system carried
by a vehicle for sensing and displaying at least one
characteristic of a material deposited on a vehicle travel
surface comprising: a platform on said vehicle for
collecting and temporarily holding a portion of a material
obtained from said vehicle travel surface; a sensing means
mounted to said platform for detecting at least one
characteristic of said collected material on said platform
and for producing a signal corresponding to said character-
istic; a microprocessor carried on said vehicle for
processing and converting said signal into a form suitable
for display and control; and a conduit means connected
between said sensing means and said processor for carrying
said signal to said processor.
In another aspect the invention provides a~
system carried by a vehicle for collecting, sensing
and displaying the freeze temperature of a material
deposited on a vehicle travel surface comprising: a
platform on said vehicle for collecting and
CA 02482691 2004-11-03
3a
temporarily holding a portion of a deposited
material obtained from said vehicle travel surface;
a selectively sealable chamber having a central
thermally conductive portion mounted on said
platform for receiving and containing a portion. of
said collected material in said central conductive
portion of said chamber; a thermoelectric
heater/cooler mounted on said cor_ductive portion of
said chamber for cooling said portion of said
collected material; and a sensor connected to said
central portion for sensing the freeze point of said
collected material as said collected material is
cooled.
One embodiment of the apparatus for sensing
surface material condition in accordance with the
present invention comprises a collection means for
receiving material discharged, for example, from a
vehicle wheel in ccntact with a roadway surface, at
least one sensing means coupled to the collection
means for detecting a characteristic of the received
material such as friction coefficients, temperature,
conductivity, and chemical concentrations and
producing a corresponding signal, processing means
CA 02482691 2004-11-03
4
for converting the corresponding signal, and display
means connected to the.processing means for
providing an indication of surface conditions based
on the material characteristics.
The collection means may include a conventional
mud flap located immediately behind a vehicle wheel
so that a portion of any surface material that is
picked up by the vehicle wheel and thrown against
the flap may be collected. An alternative
collection means is a scoop located in proximity of
the wheel or adjacent the road surface to collect
deposited surface material.
- Another embodiment of the invention does not
require a collection means,. but instead, rembtely
senses directly the surface material characteristics
such as temperature, conductivity, friction
coefficients or chemical concentrations. This
embodiment utilizes a sensor located on the
undercarriage of the vehicle at a preferably fixed
distance from the road surface which senses the
surface temperature and at 7.east one other unique
surface material characteristic so that the specific
material or materials can be identified, the
composition determined, and freezing temperatures
determined.
Another embodiment of the apparatus has a
sensor mud flap which includes a channel leading
into a detection chamber where liquid runoff from
the wheel flap is periodically collected and then
frozen. The freeze point is sensed along with the
temperature of the collected material. This
information is displayed to the operator of the
vehicle. Once the freeze goint is determined, the
frozen material is thawed and discharged from the
chamber so that a new sample may be collected and
analyzed.
CA 02482691 2004-11-03
Another embodiment of the invention includes an
endless belt of liquid absoz:bi:ng material mounted to
the flap. The endless belt collects and absorbs
Liquid collected by the flap, transports it to a
5 collector which extracts the liquid from the belt
and directs it to the sensor: means which also can be
a detection chamber where the chamber contents is
frozen in order to sense the freeze point.
The sensing means may be a single sensor or a
combination, of several sensors to detect particular
parameters of interest. The road conditions are
primarily affected by changes in temperature and
_ material concentrations. Therefore the sensing
means may include resistance temperature detectors,
thermocouple, infrared temperature sensors,
conductivity detectors, close proximity
electromagnetic radiation (~MR) transmitters and
detectors or transceivers, friction measurement
devices, and other material analysis systems such
as a spectrographic analysis system such as a mass
w ~ spectrometer. In the latter case, the mass
spectrometer or other material analysis device would
preferably be mounted inside the vehicle, with a
sample conveying means such as a belt or pump line
directing the sample from the flap or other
collection platform such as a scoop, etc. into the
analysis device, elQ., the vaporizing chamber for
_, the spectrometer. Alternatively, an ultra wide band
doppler radar or any other suitable electromagnetic
radiation (EMR) emission and detection techriique may
be used to remotely ascertain chemical and physical
characteristics of the material on the roadway
surf ace .
The processing means may include a
microprocessor for converting sensed signals to
display signals, store potential material data,
CA 02482691 2004-11-03
6
determining material identity and pertinent material
characteristics, and includes power and signal
transmission means.
The display means may bEr a panel with-
5~ indicators of the freeze point, the ambient
temperature, and connections to more detailed signal
analysis equipment such as chart recorders, tape
recording devices, or other processing equipment.
The display means may also include alarms and inputs
to automatic functions such as activating anti-lock
brake systems, or transfers from two wheel to all-
wheel drive systems, or activating chemical spreader
- control functions, etc.
These and~other objects, features, and
advantages of the system and apparatus of the
present invention will become more apparent from a
reading of the following detailed description when
taken in conjunction with the accompanying drawing
figures . .
BRIEF DESCRIPTION OF TH8 DRAWING
Fig. 1 is a perspective schematic view of a
sensor platform in accordance with a first
embodiment of the invention.. .
Fig. 2 is a black diagram of the first
embodiment of the system in accordance with the
invention.
Fig: 3 is a schematic side view of a vehicle
showing potential locations for the sensor platform
in accordance with the present invention.
Fig. 4 is a partial side view of a second
embodiment of a sensor platform of the present
invention.
Fig. 5 is a perspective view of the second
embodiment of the present invention.
Fig. 6 is a control block,diagram of the second
CA 02482691 2004-11-03
k ,y ,i
7
embodiment of the present invention.
F.ig. 7 is front view of: the display panel in
the second embodiment of the: present invention.
Fig. 8 is a schematic side view of an
alternative colleotion apparatus of a system in
accordance with the present invention.
Fig. 9 is a block diagram of a remote sensing
embodiment of the system in accordance with the
present invention.
DETAIIaED DESCRIPTION OF THE INVEl~I'fION
First Embodiment
~' - Referring now to Figs. 1 through 3, a first
embodiment of the apparatus of the invention
includes a platform 12 which is typically vertically
mounted behind a vehicle wheel 14. This platform 12
replaces and also operates as a conventional mud
flap on the vehicle 10.
As stated above, one of the objects of this
invention is to provide a unique multi-purpose
mounting platform 12, such as is shown in Fig. 1,
that enables the temporary use of materials 16 which
are typically discharged from a vehicle wheel/road
surface interface to measure certain characteristics
of the materials that have left a roadway surface
(surface materials), and to also determine certain
characteristics of the surface itself. The surface
is most commonly a road or aircraft runway surface.
Throughout this specification, use of the terms
surfaee, road, roadway, or runway are
interchangeable and are used to generally mean any
surface upon which a vehicle is operated or is
operable.
The manipulation of the characteristics of
surface materials, for instance freezing the surface
material, is one efficient and accurate way to
6
CA 02482691 2004-11-03
~ ,1
r
obtain information on the surface conditions as well
as determine the conditions of loose surface
material.
The characteristics to be measured may include
but are not limited to:
I. Material volumetric buildup, such as snow,
ice, liquid solution, i.e., depth of
material on the surface.
2. Determination of the constituents of the
chemical solutions and mixtures present,
and characteristics of the solutions and
mixtures, such as percent of a particular
chemical in solution, the freezing point
(temperature) of the solution, and the
amount or percentage of a component in the
solution and/or mixture.
3. Temperatures, both ambient and of the
material solution or mixture sensed.
The methodology of determining the
characteristics described above varies with the
characteristic being tested. For example, the
general type of material buildup may be measured via
resistivity and/or conductivity in conjunction.with
temperature.. The chemical composition of the
material on the road surface may be determined by
spectrographic techniques, or by evaluation of EMR
reflections. The percent of chemicals) in a
solution that has built up on a road surface may be
determined by measuring the resistivity and/or
conductivity of th.e collected material covering the
sensor or by evaluation of EMR reflections. The
freeze point of the solution may be ~deterrnined by a
software comparison, such as a table, look-up, when
the material components are known. The ambient
temperature is measured via a thermometer or
thermocouple which could be remote from the
CA 02482691 2004-11-03
,
9
platform. The temperature o:~ the solution/material
buildup is measured by any known appropriate sensor
means such as a thermometer, thermocouple or
infrared sensor preferably mounted on the
. platform 12.
Alternatively, the freeze point of a solution
can actually be determined b:y actually freezing the
collected solution. The freeze point is determined
~- ..by monitoring a property of 'the solution that
indicates~that the freezing temperature is reached,
such as changes in electrical conductivity. This
could eliminate the need for a look-up table.
- The sensor platform 12 can be made of a
thermoplastic material, or sensor flap material such
as urethanes or teflon, andwhich preferably has the
following characteristics:
impact/abrasion resistant;
- low surface friction to maintain slipperiness
to sheet the discharged material off,af f lap
and sensor surface (s) ;
- pliable and flexible temperature range of
plus 150 - minus ~0 F degrees without melting
or becoming brittle. ~~Operating temperature of
eighty degrees fahrenheit (80F) to minus forty
degrees fahrenheit (- .40F) ; and
- capable of using all sides for mounting of~
sensors and to be formed in such a way as to
make sure that sensed material will be directed
to the various surfaces as needed.
The sensor platform or flap 12, shown in
Fig. 1, illustrates a variety of sensors mounted on
or within it to illustrate the various mounting
configurations for the purpose of making
measurements or sensing certain characteristics of
the material that has left the road surface as a
result of turbulence or surface discharge behind the
CA 02482691 2004-11-03
1
vehicle wheel.
The platform 12 is constructed to carry or have
imbedded therein various sensors 28, 20, 22, and/or
24. These sensors, depending on their.function,~ may
5 protrude outside of or be recessed within the
finished flap 12 so,that they will be exposed to, or
not exposed to, the material to be sensed, or will
have access to the material tro be sensed. As an
alternative, the various sensors could be mounted
l0 with appropriate hardware onto an existing piece of
flap material to achieve the same effect.
For example, sensors 18 and 20 may be a
~) - conductivity detector and/ or a resistance
. temperature detector (RTD) or a thermocouple (TC)
which senses the temperature of the material on the
. surface of the flap 12 and the presence of
conductive solutions in the material such as NaCl or
KC1 or MgCl2 in order to determine the type of
material buildup. The lead wires from the
20. conductivity cell and/or the RTD or TC are either
embedded in -or mounted behind the flap 12 far
protection from abrasion and moisture..
Sensor 22 maybe a sens~r such as an RTD or TC
w mounted within an aperture 26 in the flap 12. The
aperture 26 permits the passing air flow behind the
wheel l4 to bloui clear and thus ensure that new
materiah continuously passes the sensor location.
Other sensor .locations in th.e aperture 26 are shown
in dashed lines. The aperture 26 may also be used
to direct flow of material past a sensor such as an
EMR device. .
The sensor 22A may alternatively be embedded in
the flap 12 with the tip projecting to the front
surface of the flap 12 to accurately measure the
captured material temperature.
Sensor 24 may be a RTD or TC mounted either
CA 02482691 2004-11-03
.l
I1
behind the flap I2 or embedded within it so as to be
representative of the ambient temperature of the
flap 12. Alternative sensor locations may be
incorporated into the sides or top of the f lap 12 as
indicated by the 'TS" thereon.
The flap 12 is preferab:Ly mechanically attached
to the vehicle 10. The sensor flap 12 is designed
to temporarily."catch" the discharge material from
the vehicles wheel 14. Alternatively, a separate
sensor wheel 14A may be provided as shown iri Fig. 3,
for producing material discharge to be collected by
a flap 12A which carries the sensors for making the
- measurements concerning the surface that the vehicle
is riding over as well as~detecting any buildup that
might be on the surface - even after the buildup has
lef t the surf ace .
The incident spray material must not cling to
the flap or plug any pass-through holes as new
samples must periodically be measured/sensed.
Therefore, proper material selection is an important
consideration in this first embodiment.
The sensors are connected to an in-cab display
and control panel 28 via a cable 30 as shown in
. Fig. 2. The control panel 28 is capable of
controlling, communicating with, and powering the
sensors as well as interpreting sensor data and
preferably includes display/input devices which can
display information, accept outside input, store
commands,Yand retrieve data. Alarm and control
3,0 functions are also displayed on this panel. For
example, interpreted data could include a freeze
point prediction or alert notice for the measured
solution and/or material.
Second Embodiment
A second embodiment of the surface condition
CA 02482691 2004-11-03
12
sensing system in accordance.with the invention is
shown in Figs. 4-7. The system in accordance with
the second embodiment is~specificaLly directed to
determining the freezing temperature of a surf ace
material. It includes an apparatus 38 that collects
material from the road surface into a chamber,
freezes it, determines the freezing temperature,
commura.icates the data appropriately to a
display/control console, and then thaws the
material, empties the chamber, and prepares for the
next measurement cycle. The apparatus 38,is mounted
in a location on the platform Z2 as disclosed above.
_ The apparatus 38 associated with this system is
seen i:n a side view in Fig. 4. The apparatus 38
comprises a support structure 40 made of any
suitable materials for instance a laminate of a
thermoplastic material and aluminum, and a capture
and measurement portion 42 supported below and from
the support structure 40. 'The capture portion 42
comprises an elongated chamber 44 having an open top
end 4f and an open bottom end 48 generally having ari
elongated oval cross section. The open top end 46
is for receiving any surface material that collects
above the top end 46 on the support structure 40.
The top end 46 and bottom end 48 of the chamber
44 are preferably made of a flexibly material, such
w as plastic or rubber, which is preferably able to be
selectively opened and pinched closed to allow
material to flow in and out as desired. Selective
opening and closing valve mechanisms 50 are mounted
to the apparatus at the appropriate positions
adjacent the upper and lower ends 46 and 48. When
the bottom end 48 is closed and the top end 46 is
open, collected material builds up in the
chamber 44. When both ends are closed, the
collected material is isolated. When both ends are
CA 02482691 2004-11-03
13
open, the collected material ~.s discharged from the
lower end 48.
Each of the opening and closing mechanisms 50
includes a pinch valve 52 and a solenoid 54. The
top and bottom ends 46, 48 oj the chamber 44 are
selectively opened and closed by pinch-valves 52.
When the upper solenoid 54 is energized, it extends
a shaft 55 outward and pushes a first surface 56,
engaging a flexible portion !a8 of the chamber 44
adjacent the upper open end 46, from one side and
drives the flexible portion !58 towards the other
side, which is in contact with a stationary second
_ surface 60. The open top end 46 of the chamber is
thus pinched closed between 'the first and second
surfaces 56 and 60, causing a preferably impermeable
seal to be formed at the top end of the chamber.
The bottom end 48 of the chamber 44 is closed in a
similar manner using a second solenoid operated
pinch valve 52.
The chamber 44 has a central portion 62 of a
predetermined length and width between the selective
opening and closing mechanisms 50. This portion 62
preferably has an elongated oval cross section and
is made of a conductive material, such as copper.
The central portion 62 of the chamber 44 comprising
a conductive material.is thermally coupled to
opposing plates of a thermo-electric heater/cooler
64 which controls the temperature of the. ceritrah
conductive chamber 44 using, for example, the well
known Peltier effect.
A heat sink 66 surrounds the chamber 44,
preferably on all sides, along the length of the
chamber 44 to facilitate the heating and cooling
process as a result of the operation of the thermo-
electric heater/cooler 64.
A liquid exiting aperture 68 is formed in the
CA 02482691 2004-11-03
__1
~4
chamber 44 above the first surface 56 to allow any
surface material draining into the liquid capture
gap 70 to exit the chamber 44 when the flexible
portion 58 of the chamber 44 is closed during
operation of the thermo-elecaric heater/cooler 64.
The draining liquid flows do>wn over the heat
sinks 66, preferably thereby beneficially affecting
the heat transfer capabilities of the heat sinks 66.
Operation
The operation of this ;second apparatus may be
either automatic or manual. In automatic operation,
_ the apparatus operates continuously or at a
predetermined cycle frequency as determined by the
25 user. Tn manual mode, the user actuates the
apparatus each time road surface condition
information is desired. This second embodiment of
the road surface sensing system is used to collect
surface material and accurately determine the
freezing point of such material regardless of
material composition.
The apparatus is positioned on the vehicle such
that it is exposed to the spray of the surface
material caused by the motion of the vehicle, as is
schematically shown in Fig.3. The apparatus may be
positioned behind front or rear wheels, or may
optionally include a separate wheel or scoop device
to pick up material from the road surface.
Referring now to the perspective view of the
apparatus 42 in Fig.. 5, when a measurement is to be
taken, the bottom end 48 of the chamber 44 is
closed. The surface material_spray contacts the
support structure 401 runs down the support
structure 40 under the inf=Luence of gravity into the
liquid capture gap 70. The surface material
collects in the chamber 44 either for a programmable
CA 02482691 2004-11-03
...,? ~v
y
predetermined period of time, preferably about 5 to
10 seconds, or until the appropriate liquid level is
obtained, at which time the top end 46 is closed by
closure of the upper pinch valve 52 to preclude
5 entry of material that could contaminate the sample
during measurement.
When a sufficient amount of surface material is
collected in the chamber 44 and the upper pinch
valve 52 is closed and the the~no-electric cooler 64
10 is activated to freeze the collected surface
material. The electrical conductivity of the
collected surface material is monitored in the
_ chamber 44 during the cooling process to establish
the freezing point of the. surface material. This
15 freezing point is communicated appropriately to the
processor and display console 72, shown in Fig.
After the freezing point is determined, the
thermo-electric cooler 64 is activated to heat the
conductive chamber portion 62 to melt the surface
material. The bottom end 48 is then opened by de-
energizing the lower pinch valve 52 to allow the
surface material to exit the: chamber 44. The
process can then be repeated to obtain a new
reading.
More particularly, referring to Fig. 6, and to
Fig. 7, automatic operation of the apparatus in
accordance with this embodiment of the invention
proceeds as follows. The user places the
automaticjmanual selector switch 80 in the automatic
position. When the switch Ei0 is placed in the
automatic position, a signal 82 is sent to close the
bottom valve and a signal 84 3s provided to de-
energize the upper solenoid valve 52 so that
collected material may flow into the chamber 44.
The control system then pau;aes for a predetermined
amount of time, such as ten seconds, in block 86.
CA 02482691 2004-11-03
\)
16
At the expiration of this wait period, a signal
88 is sent to close the upper valve 52 in order to
isolate the sensing portion 62 of the chamber 44.
Preferably, another programmable wait period 90 of a
predetermined length of time is conducted after
which the processor tests whether the contents of
the central portion 62 of the chamber 44 is
conductive. This test of conductivity 92 is
necessary in order to sense whether there is any
material collected~~.n the chamber. If the material
collected in the chamber is conductive, a signal 94
is sent to turn on the thermo-electric heater/cooler
64 ~in the cooling mode. Conductivity is continually
monitored in block 96 to determine a significant
change in conductivity, as the material in the
central portion &2 of the chamber 44 is cooled,
which indicates that the threshold to freezing has
been reached. This threshold is normally indicated
by a substantial change in magnitude of the
conductivity aignal. If the threshold of freezing
is detected in block 96, the processor then sends a
signal 98 to turn on the heater until it reaches a
temperature substantially greater than the
threshold, for example, about 50 Fahrenheit. When
this temperature is reached, a control signal 100 is
sent to de-energize both upper and lower solenoid
valves 52 for a programmable period of time
sufficient to permit the collected material to drain
from the chamber 44, for example, ten seconds.
On the other hand, if, in block 96, no
threshold crossing was sensed, an abort action
display message signal 102 is displayed and the
automatic process steps 80 through 96 are repeated.
Referring now to Fig. 7, the display console
includes an on/off switch :L04, a start switch 106, a
purge switch 108, and a display 110. Manual
CA 02482691 2004-11-03
17
operation or automatic operation is selected by
switch 80: When the manual operation is selected,
the purge switch 108 may be .pressed by the operator.
This de-energizes both inlet and outlet valves 52,
allowing any materials contained in the chamber 44
to be discharged. The start switch 106 is pressed
and the automatic or manual control process shown in
the flow chart in Fig. 6 is performed from block 82
through block 100. After th.e chamber temperature
has reached 50° in block x.00, the processor
determines in block 112 whether switch 80 is in the
automatic, or manual position.. If in the manual
_ position, a signal is sent t.o leave both valves 52
open and await further manual instructions. If
switch 80 is in the automatic position, however, the
process is automatically directed to block 82 in
which the bottom valve 52 i~~ closed and the sample
collection and evaluation process is repeated a
programmable number~of times.
Referring now to Fig. E3, the apparatus in
accordance with the second embodiment may be
modified to include a collection apparatus 120 that
incorporates an endless belt 122. In operation, the
endless belt 122 moves in the direction of the
arrow 124. Road debris thrown up by the vehicle
moves and impinges on belt :L22 in the direction .
shown by arrow 126. The lower pulley 128 is
preferably either hydraulic motor driven or
electrically .driven. The upper pulley 130 is
preferably spring biased away from the motor driven
pulley 128 ta.maintain tension on the belt 122. A
collection hopper 132 is positioned below the motor
driven pulley 128 and discharges into the open upper
end 46 of the collection chamber 44 above described.
A scraper 134 is positioned adjacent the front
facing portion of the belt 122 before the belt 122
CA 02482691 2004-11-03
~: __.i ,.1
18
enters the hopper 132 so that as it enters.the
hopper 132, leaves and other solid debris may be
scraped from the belt 122.
A pinch idler pulley 136 is mounted adjacent
~ the motor driven pulley 128. As the belt moves
around the pulleys counterclockwise as shown in Fig.
8, liquid picked up from the road is "~squeegeedt'
into the hopper 132 as the belt 122 passes between
idler pulley 136 and driven pulley 128. A spring-
20 loaded clutch 138' may also be provided on the motor
driven pulley so that the collection apparatus 120
does not operate while the central portion 62 of the
collection chamber 44 is isolated.
Thud~Embod3ment
A block diagram of a third embodiment of the
sensing system in accordance with the present
invention is illustrated in Fig. 9. This third
embodiment is a completely remote sensing apparatus
20, which is mounted on the vehicle. This system 200
includes at least on.e e3:ectromagnetic radiation
transceiver 202 which emits a ultra-wide band (UWB)
impulse radar. A very short electromagnetic impulse
is.propagated from transceiver 202 and echoes that
reflect from the road surface 204 are evaluated.
These reflected signals are set to a depth processor-
206, a density processor 208, and at least a
chemical composition processor 210. The EMR.
reflected pulse may be utilised directly by the
depth processor 20&..to determine the depth of any
surface~layer of material on the roadway. However,
the density processor, and composition processors
208 and 210 rely also on input from a database 212
to determine, by comparison to peak height or phase
shift of the reflected signal versus the incident
signal, ors, output which is unique to a particular
CA 02482691 2004-11-03
19
chemical composition and density. Comparing these
outputs to the database content produces or can
result in quantitative density and composition
information 214 which is, in turn, fed to computer
216 along with depth information 218.
The depth 218 is processed in the computer 216
to provide a display 220 with information necessary
to determine what additional chemicals need to be
deposited on the road surface in order to minimize
the hazardous conditions. In addition, the
computer 216 may provide a direct output to a
control device for automatically dispensing, the
_ appropriate amounts of chemicals to the road surface
as the vehicle drives by.
An infrared transceiver 222 is also mounted on
the vehicle and is directed toward the road surface.
The transceiver 222 provides. an output to a road
temperature processar 224 which in turn also-feeds
an output to the computer 21.6 indicative cf the
actual road surface temperature.
The apparatus 200, in. accordance with the third
embodiment of the present invention, may be
compactly designed for unitary installation in the
cab of a road maintenance vehicle, such as a salt
truck, with the display 220 and a keyboard input
device 226 integrated into i:.he dashboard of the
vehicle. The driver can then input to the
computer 226 desired deicin~~ concentrations or other
desired input information The computer 216 then
can compare the acCual composition and status of the
material actually on the road and either display or
automatically contral the dispensing of additional
chemicals to the road surface.
The apparatus and system in accordance with the
present invention has been described with reference
to particular embodiments thereof. Therefore, the
CA 02482691 2004-11-03
above description is by way of illustration and not
by way of limitation. Accor~ding~.y,.it is intended
that all such alterations anal variations and
modifications to the embodiments are within. the
scope of the present invention as defined by the
appended claims. _
