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Title:
VEHICLE PROXIMITY SENSOR FOR IN-GROUND INSTALLATION
Document Type and Number:
WIPO Patent Application WO/2020/127268
Kind Code:
A1
Abstract:
A vehicle sensor (100) suitable for installation in the ground. The vehicle sensor (100) includes a housing unit comprising a rigid lower part (104) and an upper part (102). The upper part (102) has a resilient, convex upper surface (114). The upper part (102) is sealed onto the lower part (104) using a clamping band (106).

Inventors:
BLEKKEN BRAGE (NO)
MYRHOL AUDUN JAN (NO)
LYKKJA OLA MARTIN (NO)
Application Number:
PCT/EP2019/085654
Publication Date:
June 25, 2020
Filing Date:
December 17, 2019
Export Citation:
Click for automatic bibliography generation   Help
Assignee:
Q FREE ASA (NO)
International Classes:
G01D11/24; E01F11/00; G08G1/14; H03K17/95; G01S7/02; G01S7/481; G01S7/497; G01S7/52; G01S7/521; G01S13/04; G01S13/86; G01S15/04; G08G1/01
Domestic Patent References:
WO2010069002A12010-06-24
Foreign References:
EP1965046A12008-09-03
US4731178A1988-03-15
KR20100013432A2010-02-10
US2236302A1941-03-25
US20160328961A12016-11-10
EP3070491A12016-09-21
US20140343891A12014-11-20
Attorney, Agent or Firm:
DEHNS (GB)
Download PDF:
Claims:
Claims:

1. A vehicle sensor suitable for installation in the ground with a housing unit comprising:

a rigid lower part and an upper part with a resilient, convex upper surface, wherein the upper part is sealed onto the lower part using a clamping band.

2. The vehicle sensor as claimed in claim 1 , wherein the clamping band is made from a metal.

3. The vehicle sensor as claimed in any preceding claim, wherein the lower part comprises at least one ridge and the upper part comprises at least one groove in an area of contact between the upper and lower parts.

4. The vehicle sensor as claimed in any preceding claim, wherein the lower part comprises a ridge located at a base thereof for aiding retention of the clamping band in a desired position.

5. The vehicle sensor as claimed in any preceding claim, wherein the upper and lower parts are made from the same material.

6. The vehicle sensor as claimed in claim 5, wherein the upper and lower parts are made from high density polyurethane.

7. The vehicle sensor as claimed in any preceding claim, comprising a

magnetometer.

8. The vehicle sensor as claimed in any preceding claim, comprising a radar transmitter and/or receiver.

9. The vehicle sensor as claimed in any preceding claim, comprising an ultra wideband radar transmitter and/or receiver. 10. The vehicle sensor as claimed in any preceding claim, comprising an ultrasound ranging sensor or an optical sensor.

Description:
VEHICLE PROXIMITY SENSOR FOR IN-GROUND INSTALLATION

This invention relates to vehicle sensors particularly, but not exclusively, for installation in the ground.

Such sensors are often utilized in car parks and roads to sense vehicles parked or passing. In car parks such sensors allow a determination as to whether a certain space is occupied by a vehicle. This allows for more accurate alerts and directions for drivers to available spaces. Vehicle proximity sensors may also be installed within a road surface, utilized to detect the presence of vehicles on the road which can allow for more efficient toll systems and monitoring of traffic flow without the need for gantry

architecture.

However, vehicle sensors are often subjected to a variety of extreme conditions. Owing to their typical outdoor installation, the sensors must be capable of withstanding a multitude of weather conditions, particularly snow, rain and ice. Moisture and dust infiltrating the housing of the sensor is likely to result in the failure of its electronic systems. Furthermore the sensor must be capable of withstanding the force of heavy vehicles without fracturing of the housing. In situations where sensors are installed in the road surface of a busy road, it may be difficult to replace a faulty sensor and therefore the sensor is required to have a long lifetime as well as resilience to extreme conditions.

The Applicant has appreciated it would be advantageous to provide a sensor with a housing capable of withstanding the aforementioned extreme conditions and large forces so as to minimize the need for re-installation of the sensors.

When viewed from a first aspect the invention provides a vehicle sensor suitable for installation in the ground with a housing unit comprising:

a rigid lower part;

an upper part with a resilient, convex upper surface; wherein the upper part is sealed onto the lower part using a clamping band.

Thus it will be seen by those skilled in the art that in accordance with at least embodiments of the invention, a vehicle sensor has a housing unit which provides beneficial protection of electronic components of the sensor placed inside the housing by preventing the infiltration of moisture and dust.

The resilient, convex upper surface of the upper part increases the robustness of the housing as it allows the upper surface to deform under the force of a heavy vehicle which may help to reduce stress in the material and prevent fractures. The convex upper surface advantageously discourages precipitation from pooling on the sensor which can affect functioning of the vehicle sensor. For example the pooling of water on top of the sensor might hinder the functionality of the sensor and so result in a less accurate measurement of whether a vehicle is above the sensor or not.

Implementing a clamping band may ensure a controlled pressure over the area of contact between the upper part and lower part. Furthermore, the use of the clamping band may obviate the requirement to use an adhesive or o-ring to seal the upper and lower parts together to produce a secure, watertight mating.

In a set of embodiments the clamping band is made from a metal and in a preferred set of embodiments from steel. Flowever, a skilled person will appreciate there are a variety of different materials that would be a suitable material for a clamping band such as aluminium, titanium, nylon etc.

In set of embodiments the lower part comprises at least one ridge in an area of contact between the upper part and lower part. Preferably, the upper part comprises at least one groove in an area of contact between the upper and lower part. In a subset of embodiments the at least one ridge on the lower part corresponds to the at least one groove in the upper part. This allows for the ridge to mate with a corresponding groove to help produce a secure, watertight mating between the upper and lower parts without requiring an adhesive or o-ring. In a set of embodiments the lower part comprises a ridge located at the base of the lower part. This ridge may allow for precise positioning of the of the upper part and lower part. This ridge may also aid the retention of the metal clamping band in the desired position.

The rigid part may be formed from a variety of materials as will be appreciated by a person skilled in the art. For example, the rigid part may be formed from a metal or plastic. In the context of the present invention, the term‘rigid’ implies the part is sufficiently stiff so that it is not deformed under a large force e.g. the weight of a large vehicle such as a lorry. In a set of embodiments the rigid part is formed using a mould.

The upper part may also be formed from a variety of materials. In the context of the present invention,‘resilient’ implies the upper surface of the upper part can be depressed inwards towards the rigid part under a large force e.g. the weight of a vehicle, and upon removal of the force returns to its initial shape.

Whilst the upper and lower parts may be manufactured from different materials, in a set of embodiments the upper and lower parts are made from the same material. In a set of embodiments the upper and lower parts are made from high density polyurethane.

In a set of embodiments, the vehicle sensor comprises a magnetometer. Using a magnetometer allows changes in the local magnetic field caused by a vehicle to be detected. In a set of embodiments, the vehicle sensor comprises a radar sensor. The radar sensor may comprise a radar transmitter and/or receiver. In a set of embodiments the vehicle sensor comprises a ultra wideband radar sensor. The ultra wideband radar sensor may comprise an ultra wideband radar transmitter and/or receiver. Ultra wideband radar is advantageous as it does not use much power and naturally has a short-range, therefore using an ultra wideband radar may allow a better operating lifetime. The vehicle sensor could also comprise an ultrasound ranging sensor or an optical sensor. The use of an optical sensor may require a transparent window in the convex upper surface of the upper part. Certain embodiments of the present invention will now be described, by way of example only, with reference to the accompanying drawings in which:

Figure 1 a shows the external housing of a vehicle sensor in accordance with an embodiment of the invention;

Figure 1 b shows a cross-section of the vehicle sensor;

Figure 2 is a schematic block diagram of the electronic components of the vehicle sensor;

Figure 3 is a flow chart of the installation process of the vehicle sensor in a road surface; and

Figure 4 is an exemplary application of the vehicle sensors as parking sensors.

Figure 1 a shows the external housing of a vehicle sensor 100 embodying the invention and Figure 1 b shows a cross-section through the sensor 100, which is formed primarily from an upper part 102 and a lower part 104 both made for example of a plastic material such as a high density polyurethane. A downwardly open skirt portion of the upper part 102 of the housing fits tightly over the lower part 104 and is secured using a clamping band 106.

The upper part 102 of the housing has a convex surface 1 14 as seen in both Figures 1 a and 1 b. Precipitation on top of the sensor can be problematic as it affects the

propagation of signals used for vehicle detection (as explained below) and can result in an inaccurate reading as to whether a vehicle is above the sensor or not. By

implementing a convex surface, precipitation such as rain is prevented from pooling on top of the sensor, with the water instead running off the convex surface.

The clamping band 106 ensures a controlled pressure over the area of contact between the upper part 102 and the lower part 104. The clamping band 106 may, for example, be made of steel. The clamping band 106 fits in a recess in the outer surface of the upper part 102. The recess helps the clamping band 106 to remain in a fixed position on the upper part 102. To fit the clamping band 106 onto the upper part 102 to secure the upper 102 and lower 104 parts in place, the clamping band may be pulled tightly around the upper part and then crimped. Alternatively, a ratchet mechanism may be

implemented. The skirt portion of the upper part 102 may be undersized to increase the tightness of the fit between it and the lower part 104. One or more small ridges 108, 110 are present on the outer surface of the lower part 104 (e.g. 1 mm height from the outer surface) to engage in corresponding grooves in the upper part 102. These ridges act to deform the upper part 102 to further tighten the fit between the upper part 102 and lower part 104.

A further ridge 112 is located at the base of the lower part 104 for precise positioning of the upper part 102 and the lower part 104. A combination of the clamping band 106 and ridges 108, 110, 112 helps to produce a secure, watertight mating of the upper 102 and lower parts 104 without the need for an adhesive or o-rings. Those skilled in the art will of course appreciate that many other ways of providing a secure fit between the parts may be envisaged.

A circuit board 116 containing the electronics required for the vehicle sensor is located on top of the lower part 104. The circuit board 116 contains all the electronic

components of the sensor. A schematic block diagram of the electronic components of a vehicle sensor is seen in Figure 2. The sensor includes an orientation sensing arrangement 202 which comprises an orientation sensor such as an accelerometer 204 and a microcontroller 206. The accelerometer 204 provides an acceleration

measurement to the microcontroller 206 e.g. every 5 seconds. The microcontroller 206 determines from the output of the accelerometer 204 whether the sensor has had its orientation changed from an initial to a subsequent orientation e.g. when the sensor has been taken from a storage box in which it is stored upside down and fitted in the ground. The microcontroller 206 further tracks the number of acceleration measurements the orientation has remained approximately constant for. This allows the microcontroller 206 to determine that the orientation has intentionally been changed from the initial to the subsequent orientation for installation in a road surface. The microcontroller 206 can alter the power supplied by the battery to a proximity sensing circuit portion 208 and communication circuit portion 212 depending on whether the sensor is in the initial or subsequent orientation. The accelerometer 204 and microcontroller 206 may be powered by a battery 214 also contained within the sensor. This allows the sensor to be powered only when it is ready to be installed and thus maximizes battery life. As seen in Figure 2 the sensor further includes a proximity sensing circuit portion 208 which may comprise a magnetometer 210. The applicant appreciates in other exemplary embodiments the proximity sensing circuit portion may comprise an ultra wideband radar sensor. The proximity sensing circuit portion 208 is supplied with power from the battery 214. The power supplied is controlled by the orientation sensing arrangement 202. The magnetometer 210 detects changes in the local magnetic field caused by a vehicle disturbing the magnetic field in the vicinity of the sensor. The magnetometer 210 may then provide an appropriate signal to the communication interface circuit portion 212 for transmission to a remote device. The communication circuit portion 212 interface thus includes a transmitter 218, and potentially also a receiver 220. These may use the same aerial (not shown).

The proximity sensing circuit portion 208 may comprise a separate microcontroller for determining the presence of a vehicle in the vicinity of the sensor from the

measurements from the magnetometer 210. Alternatively, the same microcontroller 106 as used in the orientation sensing arrangement may be utilized. Provision of a microcontroller allows for a binary signal to be transmitted from the communication circuit portion interface 212 corresponding to either the presence or absence of a vehicle. This can remove the requirement for a remote server to determine whether a vehicle is present from the magnetic field measurement. For example, the

communication circuit portion interface 212 may simply transmit a signal to a receiver connected to a light source, where a signal indicating a vehicle is present above the sensor triggers the receiver to switch off the light source. Additional information may also be included for the benefit of the user and/or operator of the road or car park.

The sensor unit may contain additional sensors 216. Possible additional sensors may include ultrawide band radar, an ultrasound sensor, an infra-red laser or a visible light laser to increase the accuracy of the determination of the presence of a vehicle by the sensor. Other additional sensors which may be installed provide additional information which may be beneficial to the user or operator of a road/car park include temperature and pressure sensors. Figure 3 is a flow chart demonstrating the installation/ commissioning procedure for a vehicle sensor. In first step 302 the sensor is stored in a storage box post manufacture in the initial orientation (i.e. upside down) in order to limit or prevent power from being supplied to the proximity sensing circuit portion 308 or other circuitry in standby mode.

In step 304 the sensor is then removed from the storage box by an installer. In step 306 the installer rotates the sensor through 180 degrees from the initial orientation to the subsequent orientation (i.e. the right way up). In step 308 the sensor is then placed and sealed in a hole in the ground with the top surface of the upper part of the housing of the sensor flush with the surface of the ground. The hole in which the sensor is placed is usually previous dug in the road surface and as roughly the shape of a cylinder with a slightly larger diameter than the sensor. Cement based adhesives or epoxy glue may then be used to secure the sensor within the hole. The convex face of the upper part of the housing sits slightly above the level of the road surface, and should be left uncovered. After a predetermined interval of being in the subsequent orientation, in step 310, power is supplied to the proximity sensing circuit portion 308 and the

communication circuit portion 312, then the sensor is commissioned i.e. functions to detect proximity of a near-by vehicle and to transmit signals indicating this. The sensor is then successful installed in the ground and can be used to detect the presence of vehicles above it.

An example of the disclosed sensors’ implementation as parking sensors is shown in Figure 4. Within a car park 400, a vehicle sensor 402 is installed in each of the parking spaces 404, 406, 408, 410. The vehicle sensor 402 in parking space 404 does not detect the presence of a car, therefore transmits a signal to a remote server that there is no vehicle present in the space. The vehicle sensor 402 in parking space 408 detects the presence of a vehicle 412, and therefore transmits a signal to the remote server that there is a vehicle present in the space. The remote server may then, for example, provide a signal to light sources above an occupied space to be turned off whilst light sources above empty spaces are kept on. Typically to preserve battery life, vehicle presence information is only transmitted when the occupancy state changes.

Thus it will be appreciated by those skilled in the art that the specific embodiments of the inventive concepts described herein provide a reliable, long-life housing for a vehicle sensor. This may provide significant benefits over known systems. It will further be appreciated however that many variations of the specific arrangements described here are possible within the scope of the invention.