GB2480716A

GB2480716A - Road surface and tyre condition monitoring apparatus

Info

Publication number: GB2480716A
Application number: GB1021713A
Authority: GB
Inventors: Per Magnussen
Original assignee: Modulprodukter AS
Current assignee: Modulprodukter AS
Priority date: 2010-05-18
Filing date: 2010-12-22
Publication date: 2011-11-30
Also published as: GB201021713D0

Abstract

A road surface condition monitoring apparatus (10) includes a radiation source arrangement (150, 160) for generating radiation (170) for interrogating a road surface (100), and a detector arrangement (200, 210, 220) for receiving radiation reflected in operation from the road surface (100) to generate a corresponding reflected radiation signal (S3), and a computer arrangement (20) for receiving the reflected radiation signal (S3) for determining frictional properties of the road surface (100). The computer arrangement (20) is operable to compare the reflected radiation signal (S3, R) with a corresponding expected reflected radiation signal (Reap) for a given position for determining the frictional properties of the road surface (100). A mathematical model may be employed based on at least one of: a neural network, a physical model and a measurement database. The apparatus may include a GPS position determining arrangement. Fan and heater arrangements for the radiation tubes are disclosed to reduce blockage thereof by snow and ice. The radiation source may generate modulated radiation and the receiver may be adapted to demodulate the reflected radiation. A similar apparatus is disclosed to determine the frictional properties of a tyre surface wherein the reflected radiation signal for the tyre surface is compared with a corresponding expected reflected signal for the tyre surface.

Description

ROAD SURFACE CONDITION MONITORING APPARATUS

Field of the invention

The present invention relates to road surface condition monitoring apparatus. Moreover, the present invention also concerns methods of monitoring road surface condition. Furthermore, the present invention relates to software products recorded on machine readable data storage media, wherein the software products are executable on computing hardware for implementing aforesaid methods.

Background of the invention

Satisfactory adhesion of vehicle tyres (USA: tires) to road surfaces is generally appreciated by vehicle drivers to be an important safety issue when driving, especially in icy, snowy and wet weather conditions. In contemporary vehicles, automatic braking system (ABS) functionality is routinely provided in top-of-range vehicle models and operates by detecting a sudden angular acceleration of vehicle wheel rotation with an associated sudden drop in wheel torque. ABS functionality operates to maintain a braking force applied to vehicle wheels at just below a threshold where wheel slip occurs. However, ABS does not seek to monitor actual road surface condition and therefore is unable to anticipate potentially hazardous road conditions to be encountered at a future time.

It is known from a published PCT patent application no. W02004/016485 Al (Nederlandse Organisate voor Toegepastnatuurwe Tenschappelijk Onderzoek TNO) to employ a configuration of diverse sensors to sense properties of a road surface and therefrom deduce a potential frictional characteristic of the road surface. HowevQj, the configuration of diverse sensors is potentially costly and complex to implement, and is also potentially degraded by dirt and other contamination often encountered on undersides of vehicles after prolonged use. So far, there appears to be a lack of commercial vehide manufacturers which have attempted to provide road surface condition monitoring functionality in their commercial production vehicles, and a generally tendency amongst contemporary vehicle manufacturers has been to provide solely well-known ABS functionality.

Road surface conditions are prone in practice to vary greatly, with different types of asphalt being employed in different sections of road which has tended to confuse contemporary road surface monitoring apparatus. Moreover, known types of camera-based road inspection systems tend to require considerable computing resources to function, thereby rendering them expensive to manufacture on account of a cost of computer parts required.

Furthermore, camera-based systems are also susceptible to generate false results in an event that their associated camera field of view is obscured by road debris after prolonged use. This variability of road surface conditions has tended to confuse contemporary road surface monitoring apparatus such that reliable detection of films of oil, thin ice layers and slippery organic debris on road surfaces has been difficult to implement reliably. In consequence, road friction monitoring has not substantially advanced beyond ABS.

Summary of the invention

The present invention seeks to provide a road surface condition monitoring apparatus which is more effective and easier to implement than known contemporary road surface condition monitoring apparatus.

Moreover, the present invention seeks to provide a method of monitoring road surface condition which is more reliable and easier to implement.

According to a first aspect of the present invention, there is provided a road surface condition monitoring apparatus as claimed in appended claim 1: there is provided a road surface condition monitoring apparatus including a radiation source arrangement for generating radiation for interrogating a road surface, and a detector arrangement for receiving radiation reflected in operation from the road surface to generate a corresponding reflected radiation signal (S3), and a computer arrangement for receiving the reflected radiation signal (S3) for determining frictional properties of the road surface, characterized in that the computer arrangement is operable to compare the reflected radiation signal (S3, R) with a corresponding expected reflected radiation signal (Rexp) for a given position for determining the frictional properties of the road surface.

The invention is of advantage in that comparing measured and expected radiation for a given position provides an indication of frictional properties without friction being tested by a small degree of slippage as occurs with conventional ABS.

The invention is also beneficial in that it is susceptible to being used to provide advanced warning of road surface friction properties.

Optionally, the apparatus includes one or more radiation tubes for providing a path for the radiation for interrogating the road surface and the radiation reflected from the road surface to propagate from the radiation source arrangement and to the detector arrangement respectively, wherein the apparatus further includes a fan arrangement for providing a flow of air through the one or more radiation tubes for expelling contamination from entering into the one or more tubes.

Optionally, the road surface condition monitoring apparatus is implemented so that the computer arrangement is operable to employ a mathematical model for determining the frictional properties of the road surface from at least the expected reflected radiation signal (Rexp) and the reflected radiation (R), wherein the mathematical model is based upon at least one of: a neural network, a physical model and a measurement database. More optionally, the fan arrangement includes a heater arrangement in an air flow generated by the fan arrangement when in operation, wherein the heater arrangement is arranged to heat the one or more radiation tubes to reduce blockage thereof by snow and ice.

Optionally, the road surface condition monitoring apparatus is implemented in that the radiation source arrangement is operable to generate modulated radiation for interrogating the road surface, and the receiver arrangement is adapted to demodulate the reflected radiation received thereat to generate the reflected radiation signal (S3). Optionally, the road surface condition monitoring apparatus, wherein the radiation source arrangement is operable to generate one or more radiation components within at least one following frequency ranges: 800 nm to 1.5 tm, 250 nm to 800 nm. More optionally, the road surface condition monitoring apparatus is implemented such that the computer arrangement is operable to adjust a phase angle between modulation applied to modulate the radiation for interrogating the road surface, and a reference signal (S2) employed to demodulate the reflected radiation received at the detection arrangement.

Optionally, the road surface condition monitoring apparatus is implemented so that the radiation source arrangement includes one or more of: light emitting diodes, organic light emitting diodes, laser diodes, nanowire light emitting devices, incandescent devices.

Optionally, the road surface condition monitoring apparatus fuither includes a temperature sensor arrangement for measuring a temperature in a proximity of the road surface or of the road surface.

Optionally, the road surface condition monitoring apparatus is implemented such that the temperature sensor arrangement includes an aspirated thermometer for measuring the temperature in the proximity of the road surface.

Optionally, the road surface condition monitoring apparatus further includes a communication arrangement coupled to the computer arrangement for communicating to other apparatus data including geographical position references (x, y) pertaining to the apparatus together with information pertaining to the measured reflected radiation (R) for use by the other apparatus as expected reflected radiation (Rexp). More optionally, the road surface condition monitoring apparatus is implemented so that the communication arrangement includes wireless communication apparatus.

Optionally, the road surface condition monitoring apparatus includes a position determining arrangement implemented by way of at least one of: GPS, GPRS for determining the given position.

According to a second aspect of the invention, there is provided a lyre surface condition monitoring apparatus including a radiation source arrangement for generating radiation for interrogating a lyre surface, and a detector arrangement for receiving radiation reflected in operation from the lyre surface to generate a corresponding reflected radiation signal (S3), and a computer arrangement for receiving the reflected radiation signal (S3) for determining frictional properties of the lyre surface, characterized in that the computer arrangement is operable to compare the reflected radiation signal (S3, R) with a corresponding expected reflected radiation signal (R) for determining the frictional properties of tyre surface: According to a third aspect of the invention, there is provided a road maintenance system including one or more vehicles equipped with apparatus pursuant to the first aspect of the invention, wherein the apparatus is employed to monitor road surfaces and to provide information to road maintenance service facilities for maintaining the road surfaces.

According to a third aspect of the invention, there is provided a method of monitoring a road surface condition using a road surface monitoring apparatus including: (a) using a radiation source arrangement for generating radiation for interrogating a road surface; (b) using a detector arrangement for receiving radiation reflected in operation from the road surface to generate a corresponding reflected radiation signal (S3); and (c) using a computer arrangement for receiving the reflected radiation signal (S3) for determining frictional properties of the road surface, characterized in that the method includes using the computer arrangement to compare the reflected radiation signal (S3, R) with a corresponding expected reflected radiation signal (Rexp) for a given position for determining the frictional properties of the road surface.

Optionally, the method includes using one or more radiation tubes of the apparatus for providing a path for the radiation for interrogating the road surface and the radiation reflected from the road surface to propagate from the radiation source arrangement and to the detector arrangement respectively, and using a fan arrangement of the apparatus for providing a flow of air through the one or more radiation tubes for expelling contamination from entering into the one or more tubes.

It will be appreciated that features of the invention are susceptible to being combined in various combination without departing from the scope of the invention as defined by the appended claims.

Description of the diagrams

Embodiments of the present invention will now be described, by way of example only, with reference to the following diagrams wherein: FIG. I is a schematic illustration of a road surface monitoring apparatus pursuant to the present invention; FIG. 2A is an illustration of a first configuration of a transmitting arrangement and sensing arrangement of the apparatus of FIG. I in front view; FIG. 2B is an illustration of the first configuration of FIG. 2A in side view; FIG. 3 is an illustration of a second configuration of the transmitting arrangement and sensing arrangement of the apparatus of FIG. 1 disposed to a single side of a vehicle wheel; FIG. 4 is an illustration of a practical implementation of component parts of the transmitter arrangement and sensing arrangement of the apparatus for monitoring properties of a road surface; FIG. 5 is an illustration of a practical implementation of component parts of the transmitter arrangement and sensing arrangement of the apparatus for monitoring properties of a tyre (US: tire) to grip onto the road surface; and FIG. 6 is an illustration of a system including the apparatus of FIG. I mounted upon or in vehides coupled via wireless to a server database.

In the accompanying diagrams, an underlined number is employed to represent an item over which the underlined number is positioned oi an item to which the underlined number is adjacent. A non-underlined number relates to an item identified by a line linking the non-underlined number to the item. When a number is non-underlined and accompanied by an associated arrow, the non-underlined number is used to identify a general item at which the arrow is pointing.

Description of embodiments of the invention

In overview, the present invention is concerned with a road surface condition monitoring apparatus which is operable to measure properties of a road surface; the surface is susceptible, depending upon weather conditions, to be one or more of: dry, covered in a layer of ice, covered in a layer of snow, wet, covered in organic debris such as leaves. As a further complication, road surface material in a dry clean state can vary greatly depending upon its age, composition, state of repain for example, cobblestones, asphalt, clay-stone tracks and polymer materials such as paints are often encountered. A contemporary problem with known road surface measuring apparatus is that there is often too much variability in road surface material and condition such that additional surface covering due to precipitation, for example rain and ice, is difficult to detect reliability. In consequence, known road surface monitoring apparatus is potentially susceptible to generate false alarms which can be potentially distracting to a driver of a vehicle fitted with such apparatus.

The present invention addresses such known limitations by employing a simple robust potentially low-cost sensor arrangement coupled to an on-vehicle computer, for example a microcontroller provided with associated data memory. The sensor arrangement provides the computer with measured characteristics of a given road surface, and the computer is provided with a position indication, for example from a GPS and/or GPRS spatial position location apparatus, for determining coordinates of the given position together with a database having data associating spatial positions (x, y) of the vehicle to corresponding expected measured characteristics Rexp(x, y) for the spatial positions (x, y).

Referring' to FIG. 1, there is shown a road surface condition monitoring apparatus indicated generally 10. The apparatus 10 includes a computer 20 including a data processor and data memory for executing software products recorded on a data storage medium for executing methods pursuant to the present invention. The apparatus 10 further includes a transmitter arrangement and sensing arrangement 30, an aspirated thermometer arrangement 40 for sampling air near a road surface 100, together with a GPS and/or GPRS position sensing unit 50. In operation, the apparatus 10 is mounted upon or in a vehicle 5 shown in FIG. 6 and transported around upon or in the vehicle 5 within a given geographical region. The GPS and/or GPRS position senng unit 50 determines a substantially instantaneous position (x, y) of the vehicle 5 within the geographical region and provided corresponding information as a signal S5 to the computer 20. A flow of air 330 is drawn from an immediate vicinity of the road surface 100 into a first end of a flow tube 300 by way of a partial vacuum generated by a fan unit 310, for example a series of one or more axial fans or a miniature centrifugal fan. The flow 330 passes by a thermocouple sensor 320 to generate a signal S4 indicative of road surface temperature to the computer 20. As an alternative or addition to emplong the aspirated thermometer 40, an infrared sensor is directed towards the road surface 100 to assist to generate the signal S4. As aforementioned, the signal S4 is indicative of a surface temperature of the road surface 100.

The computer 20 is operable to generate a strobe signal Si, for example a 1:i mark-space ratio square-wave signal at a frequency in a range of I kHz to 10 kHz at an amplitude of iO Volts peak-to-peak with a minimum OFF potential of 0 Volts and a maximum ON potential of 10 Volts. The signal Si is applied to a current amplifier 150 which controls a corresponding signal SlO which is applied to an arrangement of one or more radiation emitters 160, for example one or more of laser diodes, light emitting diodes (LED), organic LEDs, nanowire-based high efficiency light emitter (for example Zinc Oxide nanowire devices) or similar.

Optionally, the one or more radiation emitters 160 are implemented in a more conventional manner, for example using incandescence sources provided with modulation devices such as light cells or rotating mirrors to modulate light emitted from the incandescent sources. In operation, the arrangement 160 generates negligible radiation when the signal Si is 0 Volts and nearly their maximum light output when the signal Si is 10 Volts. The arrangement 160 includes, for example, an array of light emitting diodes; certain diodes of the arrangement 160 are operable to emit radiation at wavelengths longer than circa 800 nm, for example in a range 800 nm to 1.5 jtm wavelength, namely in a near-infrared band, whereas other of the diodes 160 are operable to emit over a broad spectrum of wavelengths within a human visible radiation spectrum, namely from 800 nm to 250 nm. Optionally, the arrangement 160 is operable to generate near-infrared radiation and/or visible radiation, for example controllable via an additional control signal generated by the computer 20 to complement the signal Si. The arrangement 160 is operable to generate an interrogating beam 170 which impinges in operation onto the road surface 100, wherefrom a portion of the impinging radiation is reflected and received at a detector arrangement 200 including one or more photosensors, for example phototransistores. Beneficially, the arrangement of emitters 160 and the detector arrangement 200 have a temporal bandwidth which is at least an order of magnitude greater than a fundamental frequency of signal components in the signal Si, namely at least an order of magnitude greater frequency response than a frequency of modulation employed. On receiving radiation reflected from the road surface 100, the detector arrangement 200 generates a signal Si 1 which is amplified by an analogue amplifier 210 to generate a corresponding amplified signal which is then demodulated via a synchronous demodulator 220 to generate a demodulated signal 83. The synchronous demodulator is beneficially implemented using one or more analogue switches, for example of a type CD4016 manufactured by various semiconductor manufacturers; alternatively, the synchronous demodulator can be implemented digitally. Use of strobed radiation for implementing the sensing arrangement 30 is beneficial to remove effects from ambient sunlight, from street lights, from other vehicle lights and so forth, so that such pseudo-constant extraneous sources do not contribute to the signal S3.

The synchronous demodulator 220 is provided with a strobe signal S2 generated by the computer 20. The strobe signal S2 is of a similar frequency to the signal Si, but the computer 20 is optionally operable to trim a phase difference between the signals Si, S2 so that a maximum output in any given area of the road surface 100 is adjusted to a maximum; in other words, the computer 20 is operable to adjust a phase difference between the signals Si, S2 to try to compensate for any signal phase changes occurring at the arrangement of emitters 160, at the detector arrangement 200 and at the amplifier 210.

As an alternative to employing strobed radiation, namely strobed modulation, for interrogating the road surface 100, other types of modulation are optionally alternatively or additionally employed, for example: frequency modulation, phase-shift modulation, amplitude modulation when of a different form to the strobed radiation.

The apparatus 10, when installed and functioning on a road vehicle, operates according to a method which includes the following (a) determining a geographical position (x, y) of the vehide by using the position sensing unit 50; (b) measuring reflected radiation from the road surface 100 using the sensing arrangement 30, namely generating a signal R(x, y) where R is the magnitude of the measured reflected radiation; (c) measuring a surface temperature T(x, y) of the road surface 100 using the thermometer 40; (d) determining from preloaded data in the data memory of the computer 20 expected values of reflected radiation Rexp(x, y) from the road surface 100 for the determined position of the vehide; and (e) using a numerical model of the road surface M(x, y, Rexp(X, y), T) programmed into the software executed by the computer 20 to determine a likely frictional property of the road surface 100 in respect of tyre adhesion thereto during driving.

Optionally, temperature sensing can be omitted.

The numerical model is beneficially based on one or more of: (I) measurements of the reflected radiation R of the road surface 100 made under dry conditions at a temperature well above water freezing point (0 °C), for example at 20 (ii) a neural network programmed with previous measurements of road surface friction condition, wherein the neural network is provided with inputs of Rexp, R and T together with an indication of frictional properties of the road surface 100; and (iii) using a physical numerical model based upon temperature, expected reflected radiation R, and measured reflected radiation R. Optionally, a combination of two or more of (i), (ii) and (iii) is employed and the computer 20 is operable to select a most reliable indication amongst them, for example based upon sensitivity analysis determined by applying small perturbations on the parameters R, Rexp and T. Optionally, when the temperature T is well above freezing point, for example 20 °C, the measured values of reflected radiation R(x, y) is employed to update the computer's 20 own database of expected reflected radiation Rexp(X, y), or communicated, for example via wireless 105, to update the expected radiation of other vehicles 5 which are similarly equipped with the apparatus 10.

On account of the apparatus 10 measuring optical reflection, it is desirable that the apparatus be mounted onto the vehicle 5 in such a manner that it is not directly struck by water and particles flung from wheels of the vehide 5 due to centrifugal forces. As illustrated in FIG. 2A and FIG. 2B, the arrangement of emitters 160 and the detector arrangement 200 are spatially positioned away from a plane 410 of a wheel and associated tyre 400 of the vehide 5 in respect of which they are mounted, for example with the arrangement of emitters 160 disposed at a first side of the wheel 400, and the detector arrangement 200 at a second side of the wheel 400 as shown in FIG. 2A. The arrangement of emitters 160 and the detector arrangement 200 are also beneficially placed up-stream or down-stream of the wheel 400 so that the wheel 400 does not obscure radiation beams from the arrangement of emitters 160 and to the detector arrangement 200, for example as illustrated in FIG. 2B. Optionally, the arrangement of emitters 160 and the detector arrangement 200 are mounted to one side of the wheel 400 as illustrated in FIG. 3, with the road surface 100 being sensed up-stream of the tyre 400 or down-stream of the tyre 400, most preferably, the friction is measured up-stream of the tyre in respect of a forward direction of movement of the vehicle 5.

A practical implementation of the arrangement of emitters 160 and the detector arrangement is illustrated in FIG. 4. In FIG. 4, the arrangement of emitters 160 and the detector arrangement 200 are housed within a protective enclosure 480 which includes an optical isolating wall 490 to prevent radiation generated by the arrangement of emitters 160 passing directly to the detector arrangement 200. The enclosure includes a fan arrangement 450, for example implemented using one or more axial fans or a small centrifugal fan, for blowing air through the enclosure 480 and out through its radiation tubes 470 to maintain the enclosure 480 and its tubes 470 free of debris by blowing away any particulate matter thrown up by centrifugal force by rotating wheels of the vehide. Optionally, a particle filter 430 is included up-stream of the fan arrangement 450 to prevent an interior of the enclosure 480 and its internal components from being covered in obscuring particles over a prolonged period of operation. Down-stream of the fan arrangement 450 is an optional heater arrangement 460 controlled by a signal S12 from the computer 20; the heater arrangement 460 is beneficially a ceramic heater element which is energized by commands from the computer 20, for example in an event that the temperature T is less than +5 °C, for warming the enclosure 480 during cold conditions, for example when snowing, to prevent ice and snow forming onto the enclosure 480 of any of its associated radiation tubes 470 when in use at lower temperature near freezing point and below. Beneficially, the tubes 470 are fabricated from extruded aluminium and their inside surface are painted or anodized to exhibit a substantially white colour.

Air blown by the fan arrangement 450 and exiting via the tubes 470 as air jets 420 does not affect or otherwise inhibit or attenuate radiation from the arrangement of emitters 160 reaching the road surface 100, nor affect reflected radiation reflected from the road surface reaching the detection arrangement 200. Such an arrangement avoids a need for using optical windows which tend to become occluded and contaminated by debris which can effect their optical transmission. The tubes 470 are beneficially angularly aligned so that their elongate principal axes are substantially parallel to ray paths of radiation from the arrangement of emitters 160 and to the detection arrangement 200 as illustrated. The tubes 470 beneficially have a length-to-diameter ratio in a range of 2:1 to 10:1, namely the tubes are elongate thin-walled components. Beneficially, the tubes 470 have a diameter in a range of 3 mm to 10 mm, and wall thickness in a range of 0.5 mm to 1.5 mm. Optionally, the tubes 470 are of rectangular cross-section to enables them to be arranged in a bunch of parallel tubes. The enclosure 480 is beneficially mounted within vehicle wheel arches, on an underside of the vehicle 5 facing the road surface, at a rear portion of the vehicle 5, at a front portion of the vehide 5.

Grip of a vehide on the road surface 100 is both a function of the road surface 100 and also a function of status and quality of tyres of the vehide 5. Optionally, the apparatus 10 can be adapted to measure characteristics of surfaces of tyres of the vehide by a variant of the apparatus 10 as illustrated in FIG. 5. In FIG. 5, the arrangement of emitters 160 is implemented by a single source, for example one or more laser diodes 500 providing a collimated strobed beam of aforementioned radiation which is passed via an optical scanning component 510, for example an actuated mirror, and via the tube 470 to scan a surface 520 of a tyre of a wheel 400 of the vehicle. The scanning component 510 is beneficially operable to deflect the beam of radiation from the laser diode 500. Radiation reflected from the tyre is received at the detection arrangement 200 to generate a received signal which is, as aforementioned, synchronously demodulated to generate a signal for the computer 20. The computer 20 is operable to receive the synchronously demodulated signal from the detection arrangement 200 and its synchronous demodulator and therefrom, in association with scanning from the scanning component 510, acquire data which describes a substantially transverse profile of the tyre from which frictional properties can be derived, for example whether the tyre is new or is severely worn.

Beneficially, a plurality of apparatus 10 pursuant to the present invention are furnished with a flow of air from the fan arrangement 450 which is commonly shared by the plurality of apparatus 10. Moreover, analysis data 60 provided by the apparatus 10 in operation is beneficially employed in a system 8 as illustrated in FIG. 6 to provide a driver of the vehicle 5 with warnings regarding potential friction problems of the road surface, for example via visual dash-board display warnings or similar. Beneficially, the data 60 is provided via a communication arrangement, for example, a wireless and/or Internet data communication link 105, to road authorities 505 responsible for maintaining roads; for example, the apparatus 10 is potentially useable for automatically warning road authorities 505 regarding road grifting and road snow clearance activities. The road authorities 505 beneficially support a server-based database for real-time information regarding road surface conditions.

Modifications to embodiments of the invention described in the foregoing are possible without departing from the scope of the invention as defined by the accompanying claims.

Expressions such as "including", comprising", incorporating", "consisting of', "have", "is" used to describe and claim the present invention are intended to be construed in a non-exclusive manner, namely allowing for items, components or elements not explicitly described also to be present. Reference to the singular is also to be construed to relate to the plural. Numerals included within parentheses in the accompanying claims are intended to assist understanding of the claims and should not be construed in any way to limit subject matter claimed by these claims. -12-

Claims

CLAIMS1. A road surface condition monitoring apparatus (10) including a radiation source arrangement (150, 160) for generating radiation (170) for interrogating a road surface (100), and a detector arrangement (200, 210, 220) for receiving radiation reflected in operation from the road surface (100) to generate a corresponding reflected radiation signal (S3), and a computer arrangement (20) for receiving the reflected radiation signal (S3) for determining frictional properties of the road surface (100), characterized in that the computer arrangement (20) is operable to compare the reflected radiation signal (S3, R) with a corresponding expected reflected radiation signal (Rexp) for a given position for determining the frictional properties of the road surface (100).
2. A road surface condition monitoring apparatus (10) as claimed in claim 1, wherein the apparatus (10) includes one or more radiation tubes (270) for providing a path for the radiation (170) for interrogating the road surface (100) and the radiation reflected ftom the road surface (100) to propagate from the radiation source arrangement (160) and to the detector arrangement (200, 210, 220) respectively, wherein the apparatus further includes a fan arrangement (450) for providing a flow of air through the one or more radiation tubes (470) for expelling contamination from entering into the one or more tubes (470).
3. A road surface condition monitoring apparatus (10) as claimed in claim 1, wherein the computer arrangement (20) is operable to employ a mathematical model for determining the frictional properties of the road surface (100) from at least the expected reflected radiation signal (Rexp) and the reflected radiation (R), wherein the mathematical model is based upon at least one of: a neural network, a physical model and a measurement database.
4. A road surface condition monitoring apparatus (10) as claimed in claim 2, wherein the fan arrangement (450) includes a heater arrangement (430) in an air flow generated by the fan arrangement when in operation, wherein the heater arrangement (430) is arranged to heat the one or more radiation tubes (270) to reduce blockage thereof by snow and ice.
5. A road surface condition monitoring apparatus (10) as claimed in claim 1, wherein the radiation source arrangement (150, 160) is operable to generate modulated radiation for interrogating the road surface (100), and the receiver arrangement (200, 210, 220) is -13-adapted to demodulate the reflected radiation received thereat to generate the reflected radiation signal (33).
6. A road surface condition monitoring apparatus (10) as claimed in claim 5, wherein the radiation source arrangement (200, 210, 220) is operable to generate one or more radiation components within at least one following frequency ranges: 800 nm to 1.5 j.tm, 250 nmto800nm.
7. A road surface condition monitoring apparatus (10) as claimed in claim 1, wherein the radiation source arrangement (200, 210, 220) includes one or more of: light emitting diodes, organic light emitting diodes, laser diodes, nanowire light emitting devices, incandescent devices.
8. A road surface condition monitoring apparatus (10) as claimed in claim 5, wherein the computer arrangement (20) is operable to adjust a phase angle between modulation applied to modulate the radiation for interrogating the road surface, and a reference signal (S2) employed to demodulate the reflected radiation received at the detection arrangement (200, 210,220).
9. A road surface condition monitoring apparatus (10) as claimed in claim 1, wherein the apparatus (10) further includes a temperature sensor arrangement (300, 310, 320) for measuring a temperature in a proximity of the road surface (100) or of the road surface (100).
10. A road surface condition monitoring apparatus (10) as claimed in ctaim 1, wherein the temperature sensor arrangement (300, 310, 320) includes an aspirated thermometer for measuring the temperature in the proximity of the road surface (100).
11. A road surface condition monitoring apparatus (10) as claimed in claim 1, wherein the apparatus (10) further includes a communication arrangement (105) coupled to the computer arrangement (20) for communicating to other apparatus data including geographical position references (x, y) pertaining to the apparatus (10) together with information pertaining to the measured reflected radiation (R) for use by the other apparatus as expected reflected radiation (R).
12. A road surface condition monitoring apparatus (10) as claimed in claim 11, wherein the communication arrangement (105) includes wireless communication apparatus.
13. A road surface condition monitoring apparatus (10) as claimed in claim 1, wherein the apparatus (10) includes a position determining arrangement (50) implemented by way of at least one of: GPS, GPRS for determining the given position.
14. A tyre surface condition monitoring apparatus (10) including a radiation source arrangement (150, 160) for generating radiation (170) for interrogating a tyre surface (400), and a detector arrangement (200, 210, 220) for receiving radiation reflected in operation from the tyre surface (100) to generate a corresponding reflected radiation signal (S3), and a computer arrangement (20) for receiving the reflected radiation signal (S3) for determining frictional properties of the tyre surface (100), characterized in that the computer arrangement (20) is operable to compare the reflected radiation signal (S3, R) with a corresponding expected reflected radiation signal (Rexp) for determining the frictional properties of tyre surface (100).
15. A road maintenance system (8) including one or more vehides (5) equipped with apparatus (10) as claimed in any one of claims 1 to 14, wherein the apparatus (10) is employed to monitor road surfaces (100) and to provide information to road maintenance service facilities for maintaining the road surfaces (100).
16. A method of monitoring a road surface condition using a road surface monitoring apparatus (10) including: (a) using a radiation source arrangement (150, 160) foi generating radiation (170) for interrogating a road surface (100); (b) using a detector arrangement (200, 210, 220) for receiving radiation reflected in operation from the road surface (100) to generate a corresponding reflected radiation signal (S3); and (c) using a computer arrangement (20) for receiving the reflected radiation signal (S3) for determining frictional properties of the road surface (100), characterized in that the method includes using the computer arrangement (20) to compare the reflected radiation signal (S3, R) with a corresponding expected reflected radiation signal (Rexp) for a given position for determining the frictional properties of the road surface (100).
17. A method as claimed in claim 16, wherein said method includes using one or more radiation tubes (270) of the apparatus (10) for providing a path for the radiation (170) for interrogating the road surface (100) and the radiation reflected from the road surface (100) to propagate from the radiation source arrangement (160) and to the detector arrangement (200, 210, 220) respectively, and using a fan arrangement (450) of the apparatus (10) for providing a flow of air through the one or more radiation tubes (470) for expelling contamination from entering into the one or more tubes (470).AMENDMENTS TO CLAIMS HAVE BEEN FILED AS FOLLOWS1. A road surface condition monitoring apparatus (10) including a radiation source arrangement (150, 160) for generating radiation (170) for interrogating a road surface (100), and a detector arrangement (200, 210, 220) for receiving radiation reflected in operation from the road surface (100) to generate a corresponding reflected radiation signal (S3), and a computer arrangement (20) for receiving the reflected radiation signal (S3) for determining frictional properties of the road surface (100), wherein the computer arrangement (20) is operable to compare the reflected radiation signal (S3, R) with a corresponding expected reflected radiation signal (Rexp) for a given position for determining the frictional properties of the road surface (100), characterized in that the apparatus (10) includes one or more radiation tubes (270) for providing a path for the radiation (170) for interrogating the road surface (100) and the radiation reflected from the road surface (100) to propagate from the radiation source arrangement (160) and to the *:" detector arrangement (200, 210, 220) respectively, wherein the apparatus further includes a fan arrangement (450) for providing a flow of air through the one or more radiation tubes *.S...* (470) for expelling contamination from entering into the one or more tubes (470). *. * * ** 2. A road surface condition monitoring apparatus (10) as claimed in claim 1, wherein the computer arrangement (20) is operable to employ a mathematical model for determining the frictional properties of the road surface (100) from at least the expected reflected radiation signal (Rexp) and the reflected radiation (R), wherein the mathematical model is based upon at least one of: a neural network, a physical model and a measurement database.3. A road surface condition monitoring apparatus (10) as claimed in claim 1, wherein the fan arrangement (450) includes a heater arrangement (430) in an air flow generated by the fan arrangement when in operation, wherein the heater arrangement (430) is arranged to heat the one or more radiation tubes (270) to reduce blockage thereof by snow and ice.4. A road surface condition monitoring apparatus (10) as claimed in claim 1, wherein the radiation source arrangement (150, 160) is operable to generate modulated radiation for interrogating the road surface (100), and the receiver arrangement (200, 210, 220) is adapted to demodulate the reflected radiation received thereat to generate the reflected radiation signal (S3).5. A road surface condition monitoring apparatus (10) as claimed in claim 4, wherein the radiation source arrangement (200, 210, 220) is operable to generate one or more radiation components within at least one following frequency ranges: 800 nm to 1.5.tm, 250 nm to 800 nm.6. A road surface condition monitoring apparatus (10) as claimed in claim 1, wherein the radiation source arrangement (200, 210, 220) includes one or more of: light emitting diodes, organic light emitting diodes, laser diodes, nanowire light emitting devices, incandescent devices.7. A road surface condition monitoring apparatus (10) as claimed in claim 4, wherein the computer arrangement (20) is operable to adjust a phase angle between modulation applied to modulate the radiation for interrogating the road surface, and a reference signal (S2) employed to demodulate the reflected radiation received at the detection arrangement (200, 210, 220).*: 8. A road surface condition monitoring apparatus (10) as claimed in claim 1, wherein the *:" apparatus (10) further includes a temperature sensor arrangement (300, 310, 320) for measuring a temperature in a proximity of the road surface (100) or of the road surface (100).9. A road surface condition monitoring apparatus (10) as claimed in claim 8 wherein the *:* temperature sensor arrangement (300, 310, 320) includes an aspirated thermometer for measuring the temperature in the proximity of the road surface (100).10. A road surface condition monitoring apparatus (10) as claimed in claim 1, wherein the apparatus (10) further includes a communication arrangement (105) coupled to the computer arrangement (20) for communicating to other apparatus data including geographical position references (x, y) pertaining to the apparatus (10) together with information pertaining to the measured reflected radiation (R) for use by the other apparatus as expected reflected radiation (Rexp).11. A road surface condition monitoring apparatus (10) as claimed in claim 10, wherein the communication arrangement (105) includes wireless communication apparatus.12. A road surface condition monitoring apparatus (10) as claimed in claim 1, wherein the apparatus (10) includes a position determining arrangement (50) implemented by way of at least one of: GPS, GPRS for determining the given position.13. A road maintenance system (8) including one or more vehicles (5) equipped with apparatus (10) as claimed in any one of claims I to 12, wherein the apparatus (10) is employed to monitor road surfaces (100) and to provide information to road maintenance service facilities for maintaining the road surfaces (100).14. A method of monitoring a road surface condition using a road surface monitoring apparatus (10) including: (a) using a radiation source arrangement (150, 160) for generating radiation (170) for interrogating a road surface (100); (b) using a detector arrangement (200, 210, 220) for receiving radiation reflected in operation from the road surface (100) to generate a corresponding reflected radiation signal (S3); and (c) using a computer arrangement (20) for receiving the reflected radiation signal (S3) for determining frictional properties of the road surface (100), * ***** characterized in that the method includes: :.o (d) using the computer arrangement (20) to compare the reflected radiation signal (S3, * R) with a corresponding expected reflected radiation signal (Rexp) for a given position for determining the frictional properties of the road surface (100); and. (e) using one or more radiation tubes (270) of the apparatus (10) for providing a path for the radiation (170) for interrogating the road surface (100) and the radiation reflected from the road surface (100) to propagate from the radiation source arrangement (160) and to the detector arrangement (200, 210, 220) respectively, and using a fan arrangement (450) of the apparatus (10) for providing a flow of air through the one or more radiation tubes (470) for expelling contamination from entering into the one or more tubes (470).