EP2310881A2 - Proximity detection device for a motor vehicle - Google Patents

Proximity detection device for a motor vehicle

Info

Publication number
EP2310881A2
EP2310881A2 EP09772701A EP09772701A EP2310881A2 EP 2310881 A2 EP2310881 A2 EP 2310881A2 EP 09772701 A EP09772701 A EP 09772701A EP 09772701 A EP09772701 A EP 09772701A EP 2310881 A2 EP2310881 A2 EP 2310881A2
Authority
EP
European Patent Office
Prior art keywords
bumper
transmitting
detection device
motor vehicle
receiving
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP09772701A
Other languages
German (de)
French (fr)
Inventor
Jean-Marcel Aubry
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Flex N Gate France SAS
Original Assignee
Faurecia Bloc Avant SAS
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Faurecia Bloc Avant SAS filed Critical Faurecia Bloc Avant SAS
Publication of EP2310881A2 publication Critical patent/EP2310881A2/en
Withdrawn legal-status Critical Current

Links

Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01V—GEOPHYSICS; GRAVITATIONAL MEASUREMENTS; DETECTING MASSES OR OBJECTS; TAGS
    • G01V3/00—Electric or magnetic prospecting or detecting; Measuring magnetic field characteristics of the earth, e.g. declination, deviation
    • G01V3/15—Electric or magnetic prospecting or detecting; Measuring magnetic field characteristics of the earth, e.g. declination, deviation specially adapted for use during transport, e.g. by a person, vehicle or boat
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01V—GEOPHYSICS; GRAVITATIONAL MEASUREMENTS; DETECTING MASSES OR OBJECTS; TAGS
    • G01V3/00—Electric or magnetic prospecting or detecting; Measuring magnetic field characteristics of the earth, e.g. declination, deviation
    • G01V3/08—Electric or magnetic prospecting or detecting; Measuring magnetic field characteristics of the earth, e.g. declination, deviation operating with magnetic or electric fields produced or modified by objects or geological structures or by detecting devices
    • G01V3/088—Electric or magnetic prospecting or detecting; Measuring magnetic field characteristics of the earth, e.g. declination, deviation operating with magnetic or electric fields produced or modified by objects or geological structures or by detecting devices operating with electric fields
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60R—VEHICLES, VEHICLE FITTINGS, OR VEHICLE PARTS, NOT OTHERWISE PROVIDED FOR
    • B60R19/00—Wheel guards; Radiator guards, e.g. grilles; Obstruction removers; Fittings damping bouncing force in collisions
    • B60R19/02—Bumpers, i.e. impact receiving or absorbing members for protecting vehicles or fending off blows from other vehicles or objects
    • B60R19/48—Bumpers, i.e. impact receiving or absorbing members for protecting vehicles or fending off blows from other vehicles or objects combined with, or convertible into, other devices or objects, e.g. bumpers combined with road brushes, bumpers convertible into beds
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60W—CONJOINT CONTROL OF VEHICLE SUB-UNITS OF DIFFERENT TYPE OR DIFFERENT FUNCTION; CONTROL SYSTEMS SPECIALLY ADAPTED FOR HYBRID VEHICLES; ROAD VEHICLE DRIVE CONTROL SYSTEMS FOR PURPOSES NOT RELATED TO THE CONTROL OF A PARTICULAR SUB-UNIT
    • B60W40/00—Estimation or calculation of non-directly measurable driving parameters for road vehicle drive control systems not related to the control of a particular sub unit, e.g. by using mathematical models
    • B60W40/02—Estimation or calculation of non-directly measurable driving parameters for road vehicle drive control systems not related to the control of a particular sub unit, e.g. by using mathematical models related to ambient conditions
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60R—VEHICLES, VEHICLE FITTINGS, OR VEHICLE PARTS, NOT OTHERWISE PROVIDED FOR
    • B60R19/00—Wheel guards; Radiator guards, e.g. grilles; Obstruction removers; Fittings damping bouncing force in collisions
    • B60R19/02—Bumpers, i.e. impact receiving or absorbing members for protecting vehicles or fending off blows from other vehicles or objects
    • B60R19/48—Bumpers, i.e. impact receiving or absorbing members for protecting vehicles or fending off blows from other vehicles or objects combined with, or convertible into, other devices or objects, e.g. bumpers combined with road brushes, bumpers convertible into beds
    • B60R19/483—Bumpers, i.e. impact receiving or absorbing members for protecting vehicles or fending off blows from other vehicles or objects combined with, or convertible into, other devices or objects, e.g. bumpers combined with road brushes, bumpers convertible into beds with obstacle sensors of electric or electronic type

Definitions

  • Proximity detection device for a motor vehicle
  • the present invention relates to a device for detecting the presence of an object in a detection zone near a motor vehicle by measuring a capacity variation caused by the presence of said object.
  • the invention also relates to a bumper comprising such a detection device, as well as to a motor vehicle comprising such a bumper.
  • Such devices are known and allow for example to assist the driver to park his motor vehicle by informing him of the proximity of the obstacles surrounding the vehicle. In general, such a device informs the driver of the presence of obstacles around the vehicle when driving.
  • the known devices of the "capacitive" type comprise one or more detection plates functioning as an oscillating circuit. A measurement of the capacitance between the detection plate (s) and the earth is made. The objects entering the detection zone of the device cause a variation of the measured capacity, for example an increase in the capacity, which makes it possible to determine the presence of the object and to evaluate its distance with respect to the vehicle as a function of the variation of the capacity between the plate (s) and the earth.
  • Such devices can detect the presence of obstacles only when the vehicle and the obstacle are moving relative to each other, that is to say when the obstacle moves relative to each other. to a stationary vehicle or when the vehicle is moving in relation to a fixed obstacle or when the vehicle and the obstacle are moving. If the obstacle and the vehicle are fixed relative to each other, the measured capacity is constant and the obstacle is not detected.
  • the invention aims to overcome these disadvantages by providing a detection device for detecting moving obstacles and obstacles. fixed with respect to the vehicle and providing an enlarged detection area compared to existing devices.
  • the invention relates to a detection device of the aforementioned type, comprising an emission element of an electric field, an element for receiving an electric field disposed at a distance from the emission element, and means for measuring the coupling capacitance between the transmitting element and the receiving element, the transmitting element emitting an electrical signal which is then received by the receiving element so that a coupling capacitance a predetermined value is established between the transmitting element and the receiving element when no object is present in the detection zone, a variation of the coupling capacitance between the transmitting element and the receiving element indicating the movement of an object in the detection zone and restoring a capacitance of a value different from the predetermined value indicating the presence of a static object in the detection zone.
  • Measuring the capacitance between a transmitter element and a receiver element provides information on moving obstacles and fixed obstacles relative to the vehicle. Indeed, when an obstacle is in motion and approaches the vehicle, the measured capacity increases, as for known devices, and when the obstacle is fixed, the capacity is established at a value different from that which is measured when no obstacle is present in the detection zone contrary to the known devices. Thus, a variation of the capacitance indicates the presence of a moving obstacle, while a capacitance of a value different from the capacitance measured without obstacle indicates a fixed obstacle.
  • the detection of a fixed obstacle is particularly advantageous, for example when the vehicle is parked and an obstacle could damage the vehicle when opening the vehicle doors.
  • the detection of fixed obstacles is also advantageous before committing the movement of the vehicle, for maneuvers in forward or reverse.
  • the detection zone is enlarged because it is easier to supply the emission element with large AC voltages, which makes it possible to have a large signal-to-noise ratio at the receiving element and thus to increase the sensitivity of the device to large distances.
  • the electric field extending between the transmitting element and the receiving element has a semicircular shape, which provides a more detection area oriented towards a zone of interest of obstacle detection. According to other characteristics of the detection device:
  • the detection device comprises a second emission element and a second element for receiving an electric field, said pair of elements being arranged to calibrate the detection device with respect to the ground and to carry out complementary measurements with the first transmission and reception elements;
  • the two pairs of transmission and reception elements are arranged to operate at different frequencies
  • the transmission element transmits a modulated signal
  • the reception element or a control electronics comprising a synchronous demodulation device making it possible to demodulate the signal received by the reception element
  • the detection device comprises a signal generator transmitting a square or sinusoidal signal to the transmission element and a square signal to the demodulation device of the reception element;
  • the detection device comprises calculation means arranged to determine the distance of the object with respect to the motor vehicle as a function of the capacitance or the capacitance variation measured on the two pairs of transmission and reception elements.
  • the invention also relates to a motor vehicle bumper comprising a detection device as described above. According to other features of the bumper:
  • the emission element is fastened to an internal transverse end portion of the bumper and the receiving element is arranged at the other internal transverse end portion of the bumper;
  • the emission element and the receiving element are embedded in the material of the bumper;
  • the second transmission and reception elements are arranged under the first transmission and reception elements of the detection device.
  • the bumper comprises at least one conductive or partially conductive surface disposed on the bumper and interposed between the emission element and the receiving element of the detection device, said surface being connected to the ground of said detection device.
  • the invention also relates to a motor vehicle comprising a bumper as described above.
  • the motor vehicle comprises a second bumper as defined above, one of the bumper being attached to the front of the motor vehicle and the other bumper being attached to the vehicle. rear of said vehicle.
  • FIG. 1 is a schematic representation of a bumper of a motor vehicle comprising a detection device according to the invention
  • FIG. 2 is a schematic representation of an equivalent electrical circuit illustrating the operation of the detection device according to the invention when no object is present in the detection zone
  • FIG. 3 is a schematic representation of an equivalent electrical circuit illustrating the operation of the detection device according to the invention, when an object is present in the detection zone.
  • FIG. 1 With reference to FIG. 1, there is described a bumper 1 intended to be fixed to the front or rear of a motor vehicle (not shown). It should be noted that the invention applies both to the front and to the rear of the vehicle, the detection device of the invention being particularly advantageous when it is installed at the front and at the rear of the vehicle. vehicle to provide a larger detection area.
  • the inner face 2 of the bumper 1 is visible.
  • the detection device described here can also be applied to the sides of the vehicle, in particular in the side rods, in order to further increase the detection zone. Lateral detection is then achieved by coupling and combining the front, rear and side devices.
  • a detection device 4 is shown schematically in FIG. 1.
  • This device comprises a transmission element 6 of an electric field, a receiving element 8 of an electric field and a control electronics 10, not shown in detail.
  • the emission element 6 is fixed, for example glued, to a transverse end portion 12 of the inner face 2 of the bumper 1, in an upper zone thereof.
  • the receiving element 8 is fixed, for example bonded, to the other transverse end portion 14 of the inner face 2 of the bumper, in an upper zone thereof.
  • These elements 6 and 8 comprise a conductive material on at least one of their faces or on both their faces.
  • the elements 6 and 8 may also be conductive surfaces applied to the inner or outer surface of the bumper or other element of the motor vehicle.
  • the elements 6 and 8 can also be embedded in the material of the part to which they are secured. According to one embodiment, the elements 6 and 8 are each formed of a plurality of transmission and reception elements.
  • the emission element 6 is connected to the control electronics 10 so as to emit an electric field which will then be received by the receiver element 8.
  • the emission element 6 is arranged to emit square modulated electrical signals or sinusoidal.
  • the control electronics 10 comprises a signal generator (not shown) transmitting a square or sinusoidal signal to the transmission element 6.
  • the emitted signal has, for example, a voltage of a substantially peak-to-peak amplitude. equal to 20V.
  • the signal emitted by the transmission element 6 operates for example at a frequency of between 50 KHz and 200 KHz. It will be understood that other frequencies can be used by adapting the control electronics 10.
  • the modulation of the emitted signal makes it possible to distinguish it from other surrounding signals, for example coming from devices for detecting other vehicles or the like, so that the receiving element 8 processes the signal emitted by the transmitting element 6 and not another. This avoids the processing of spurious signals.
  • the receiving element 8 is arranged to receive the electrical signal emitted by the transmission element 6 and to demodulate it synchronously or to transmit the received signal to the control electronics in charge of the synchronous demodulation in order to extract the signal from the surrounding noise.
  • the reception element 8 or the control electronics 10 comprises a synchronous demodulation device (not shown), known in itself, which receives a square signal from the signal generator of the signal generator.
  • the signal transmitted to the demodulation device has the same frequency as the signal transmitted to the transmitter element, that is to say between 50 KHz and 200 KHz according to the example mentioned above.
  • the receiving element 8 is for example made using an inverting amplifier associated with a tuned circuit.
  • the output is connected to the demodulation device, itself connected to a low-pass filter.
  • the tuned circuit limits the bandwidth of the receiving element to the frequency of interest of the received signal. This eliminates the large noise components that could disturb the measurement.
  • the demodulation device and the low-pass filter act as a narrow-band filter. Synchronous demodulation makes it possible to obtain a very important signal-to-noise ratio, which makes it possible to receive the transmitted signal even when it is very weak. The detection distance can thus be increased, as will be described later.
  • the control electronics 10 comprises means for measuring the coupling capacitance between the transmitting element 6 and the receiving element 8 from the signal emitted by the transmitting element 6 and the signal demodulating by the synchronous demodulation device.
  • the operation of the device described above is the following: - when no obstacle is in the detection zone, that is to say the emission zone of the electric field by the element of emission, the transmitting element 6 and the receiving element 8 are equivalent to two capacitors in series, respectively Ci and C 2 .
  • the coupling capacitance C as shown in FIG. 2, between the transmitting element 6 and the receiving element 8 then has a predefined fixed value measured by the measuring means.
  • the device when an obstacle enters the detection zone, it is equivalent to a capacitor C3 connected on the one hand to earth and connected on the other hand between the capacitor Ci of the emission element 6 and the capacitor C 2 the receiving element 8, as shown in FIG. 3.
  • the measured coupling capacity varies.
  • the coupling capacity is equal to a value different from the preset fixed value measured when no obstacle is in the detection zone.
  • the device makes it possible to determine the presence of a fixed or moving obstacle in the detection zone.
  • a transmitting element and a receiving element Due to the use of a transmitting element and a receiving element, it is possible to supply the transmission element with large voltages, which improves the quality of the transmitted signal.
  • the use of synchronous demodulation optimally isolates the signal received from the noise.
  • the transmission elements 6 and reception 8 can operate alternately by means of an electronic tilt device. These elements can also operate in purely capacitive elements.
  • the detection device 4 comprises a second pair of transmission elements 16 and reception elements 18.
  • This second pair of elements 16 and 18 also makes it possible to calculate the distance of an object in the detection zone and its position.
  • the control electronics 10 comprises calculation means arranged to determine the distance of the obstacle with respect to the bumper 1 as a function of the signals emitted by the transmission elements 6 and 16 and received and by the elements of FIG. reception 8 and 18.
  • the second pair of elements has the same structure and operates according to the same principle as the transmission element 6 and the receiving element 8 described above.
  • the signal generator of the control electronics transmits signals at a different frequency to the second pair. This frequency is also for example between 50 KHz and 200 KHz.
  • each pair operates independently of each other and the signals are not mixed.
  • the second transmission elements 16 and receiving 18 are each arranged at an end portion 12, 14 of the bumper under the transmission elements 6 and receiving 8. This second pair makes it possible to calibrate the first pair while carrying out the measurement. variations in the ground level so that the driver is not informed of these variations when determining the presence of an obstacle in the detection zone.
  • a layer of "primer”, or “primer” or “primer”, conductive is deposited on the bumper to ensure better adhesion of paint or a particular orientation of color particles .
  • the presence of this layer may have the consequence that the transmission element 6 transmits a signal to the reception element 8 directly through the primer layer without substantially sending a signal to the outside of the vehicle, which can deteriorate the detection performance of the detection device 4.
  • a conductive or partially conductive surface 20 is disposed on the inner face of the bumper 1 between the emission element 6 and the receiving element 8. This surface 20 is connected to the ground of the control electronics.
  • the surface 20 extends for example over the entire height of the bumper and is also interposed between the second transmission element 16 and receiving 18.
  • the detection device 4 described above comprises an information device of the driver of the vehicle informing it of the presence of a moving or fixed obstacle around the motor vehicle. This device can also inform the distance of this obstacle relative to the vehicle. This device informs the driver as a function of the signal emitted by the detection device, this signal indicating whether a variation of the coupling capacity or an establishment of a capacity of a different value occurs.
  • the transmitting and receiving elements may also be disposed on the outer face of the bumper or integrated within the bumper material as previously described. According to other embodiments, the transmitting and receiving elements can be placed on other parts of the vehicle, such as shock absorbers, side sticks, beams, bands, etc.
  • the detection device described above is particularly advantageous because it makes it possible to have a large detection zone around the motor vehicle, particularly if two devices are used, namely one at the front of the vehicle and the other at the vehicle. back. In addition, it can detect both moving obstacles and fixed obstacles.

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  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Remote Sensing (AREA)
  • Environmental & Geological Engineering (AREA)
  • Geology (AREA)
  • General Life Sciences & Earth Sciences (AREA)
  • General Physics & Mathematics (AREA)
  • Geophysics (AREA)
  • Mechanical Engineering (AREA)
  • Electromagnetism (AREA)
  • Automation & Control Theory (AREA)
  • Transportation (AREA)
  • Mathematical Physics (AREA)
  • Measurement Of Length, Angles, Or The Like Using Electric Or Magnetic Means (AREA)
  • Radar Systems Or Details Thereof (AREA)
  • Geophysics And Detection Of Objects (AREA)
  • Emergency Alarm Devices (AREA)
  • Switches That Are Operated By Magnetic Or Electric Fields (AREA)
  • Traffic Control Systems (AREA)

Abstract

This device (4) allows the detection of the presence of an object in a detection zone by measuring a variation in capacitance brought about by the presence of said object. It comprises an element (6) for emitting an electric field, an element (8) for receiving an electric field, and means for measuring the coupling capacitance between the emission element (6) and the reception element (8), the emission element (6) emitting an electrical signal received by the reception element (8) so that a coupling capacitance of a predetermined value is established between the emission element (6) and the reception element (8) when no object is present in the detection zone, a variation in the coupling capacitance indicating the displacement of an object in the detection zone and the establishment of a capacitance of a different value from the predetermined value indicating the presence of a static object.

Description

Dispositif de détection de proximité pour véhicule automobile Proximity detection device for a motor vehicle
La présente invention concerne un dispositif de détection de la présence d'un objet dans une zone de détection à proximité d'un véhicule automobile par la mesure d'une variation de capacité entraînée par la présence dudit objet. L'invention concerne également un pare-choc comprenant un tel dispositif de détection, ainsi qu'un véhicule automobile comprenant un tel pare-choc.The present invention relates to a device for detecting the presence of an object in a detection zone near a motor vehicle by measuring a capacity variation caused by the presence of said object. The invention also relates to a bumper comprising such a detection device, as well as to a motor vehicle comprising such a bumper.
De tels dispositifs sont connus et permettent par exemple d'assister le conducteur à garer son véhicule automobile en l'informant de la proximité des obstacles entourant le véhicule. De manière générale, un tel dispositif informe le conducteur de la présence d'obstacles autour du véhicule lors de la conduite.Such devices are known and allow for example to assist the driver to park his motor vehicle by informing him of the proximity of the obstacles surrounding the vehicle. In general, such a device informs the driver of the presence of obstacles around the vehicle when driving.
Les dispositifs connus de type « capacitifs » comprennent une ou plusieurs plaques de détection fonctionnant comme un circuit oscillant. Une mesure de la capacité entre la ou les plaques de détection et la terre est effectuée. Les objets entrant dans la zone de détection du dispositif entraîne une variation de la capacité mesurée, par exemple une augmentation de la capacité, ce qui permet de déterminer la présence de l'objet et d'évaluer sa distance par rapport au véhicule en fonction de la variation de la capacité entre la ou les plaques et la terre.The known devices of the "capacitive" type comprise one or more detection plates functioning as an oscillating circuit. A measurement of the capacitance between the detection plate (s) and the earth is made. The objects entering the detection zone of the device cause a variation of the measured capacity, for example an increase in the capacity, which makes it possible to determine the presence of the object and to evaluate its distance with respect to the vehicle as a function of the variation of the capacity between the plate (s) and the earth.
Cependant, de tels dispositifs ne permettent de détecter la présence d'obstacle que lorsque le véhicule et l'obstacle sont en mouvement l'un par rapport à l'autre, c'est-à-dire lorsque l'obstacle se déplace par rapport à un véhicule immobile ou lorsque le véhicule se déplace par rapport à un obstacle fixe ou lorsque le véhicule et l'obstacle sont en mouvement. Si l'obstacle et le véhicule sont fixes l'un par rapport à l'autre, la capacité mesurée est constante et l'obstacle n'est pas détecté.However, such devices can detect the presence of obstacles only when the vehicle and the obstacle are moving relative to each other, that is to say when the obstacle moves relative to each other. to a stationary vehicle or when the vehicle is moving in relation to a fixed obstacle or when the vehicle and the obstacle are moving. If the obstacle and the vehicle are fixed relative to each other, the measured capacity is constant and the obstacle is not detected.
En outre, de tels dispositifs ne permettent pas d'obtenir une zone de détection très importante autour du véhicule et seuls les obstacles proches du véhicule sont détectés. Le conducteur n'obtient donc l'information de la présence d'un obstacle que lorsque celui-ci est proche, ce qui peut être trop tard pour adapter la conduite à la présence de cet obstacle.In addition, such devices do not provide a very large detection area around the vehicle and only obstacles close to the vehicle are detected. The driver thus obtains the information of the presence of an obstacle when it is close, which may be too late to adapt the pipe to the presence of this obstacle.
L'invention vise à pallier ces inconvénients en proposant un dispositif de détection permettant de détecter les obstacles en mouvement et les obstacles fixes par rapport au véhicule et offrant une zone de détection agrandie par rapport aux dispositifs existants.The invention aims to overcome these disadvantages by providing a detection device for detecting moving obstacles and obstacles. fixed with respect to the vehicle and providing an enlarged detection area compared to existing devices.
A cet effet, l'invention concerne un dispositif de détection du type précité, comprenant un élément d'émission d'un champ électrique, un élément de réception d'un champ électrique disposé à distance de l'élément d'émission, et des moyens de mesure de la capacité de couplage entre l'élément d'émission et l'élément de réception, l'élément d'émission émettant un signal électrique qui est ensuite reçu par l'élément de réception de sorte qu'une capacité de couplage d'une valeur prédéterminée est établie entre l'élément d'émission et l'élément de réception lorsque aucun objet n'est présent dans la zone de détection, une variation de la capacité de couplage entre l'élément d'émission et l'élément de réception indiquant le déplacement d'un objet dans la zone de détection et rétablissement d'une capacité d'une valeur différente de la valeur prédéterminée indiquant la présence d'un objet statique dans la zone de détection. Le fait de mesurer la capacité entre un élément émetteur et un élément récepteur permet d'obtenir une information sur les obstacles en mouvement et sur les obstacles fixes par rapport au véhicule. En effet, lorsqu'un obstacle est en mouvement et s'approche du véhicule, la capacité mesurée augmente, comme pour les dispositifs connus, et lorsque l'obstacle est fixe, la capacité s'établie à une valeur différente de celle qui est mesurée lorsque aucun obstacle n'est présent dans la zone de détection au contraire des dispositifs connus. Ainsi, une variation de la capacité indique la présence d'un obstacle en mouvement, tandis qu'une capacité d'une valeur différente de la capacité mesurée sans obstacle indique un obstacle fixe. Le fait de détecter un obstacle fixe est particulièrement avantageux, par exemple lorsque le véhicule est garé et qu'un obstacle pourrait endommager le véhicule à l'ouverture des portes du véhicule. La détection d'obstacles fixes est également avantageuse avant d'engager le déplacement du véhicule, pour des manœuvres en marche avant ou arrière.To this end, the invention relates to a detection device of the aforementioned type, comprising an emission element of an electric field, an element for receiving an electric field disposed at a distance from the emission element, and means for measuring the coupling capacitance between the transmitting element and the receiving element, the transmitting element emitting an electrical signal which is then received by the receiving element so that a coupling capacitance a predetermined value is established between the transmitting element and the receiving element when no object is present in the detection zone, a variation of the coupling capacitance between the transmitting element and the receiving element indicating the movement of an object in the detection zone and restoring a capacitance of a value different from the predetermined value indicating the presence of a static object in the detection zone. Measuring the capacitance between a transmitter element and a receiver element provides information on moving obstacles and fixed obstacles relative to the vehicle. Indeed, when an obstacle is in motion and approaches the vehicle, the measured capacity increases, as for known devices, and when the obstacle is fixed, the capacity is established at a value different from that which is measured when no obstacle is present in the detection zone contrary to the known devices. Thus, a variation of the capacitance indicates the presence of a moving obstacle, while a capacitance of a value different from the capacitance measured without obstacle indicates a fixed obstacle. The detection of a fixed obstacle is particularly advantageous, for example when the vehicle is parked and an obstacle could damage the vehicle when opening the vehicle doors. The detection of fixed obstacles is also advantageous before committing the movement of the vehicle, for maneuvers in forward or reverse.
En outre, la zone de détection est agrandie car il est plus facile d'alimenter l'élément d'émission à des tensions alternatives importantes, ce qui permet d'avoir un grand rapport signal sur bruit au niveau de l'élément de réception et ainsi d'augmenter la sensibilité du dispositif à des distances importantes. En outre, le champ électrique s'étendant entre l'élément d'émission et l'élément de réception présente une forme semi-circulaire, qui permet d'obtenir une zone de détection plus orientée vers une zone d'intérêt de détection d'obstacles. Selon d'autres caractéristiques du dispositif de détection :In addition, the detection zone is enlarged because it is easier to supply the emission element with large AC voltages, which makes it possible to have a large signal-to-noise ratio at the receiving element and thus to increase the sensitivity of the device to large distances. In addition, the electric field extending between the transmitting element and the receiving element has a semicircular shape, which provides a more detection area oriented towards a zone of interest of obstacle detection. According to other characteristics of the detection device:
- le dispositif de détection comprend un deuxième élément d'émission et un deuxième élément de réception d'un champ électrique, ladite paire d'éléments étant agencée pour calibrer le dispositif de détection par rapport au sol et pour réaliser des mesures complémentaires avec les premiers éléments d'émission et de réception ;the detection device comprises a second emission element and a second element for receiving an electric field, said pair of elements being arranged to calibrate the detection device with respect to the ground and to carry out complementary measurements with the first transmission and reception elements;
- les deux paires d'éléments d'émission et de réception sont agencées pour fonctionner à des fréquences différentes ;the two pairs of transmission and reception elements are arranged to operate at different frequencies;
- l'élément d'émission émet un signal modulé, l'élément de réception ou une électronique de commande comprenant un dispositif de démodulation synchrone permettant de démoduler le signal reçu par l'élément de réception ;the transmission element transmits a modulated signal, the reception element or a control electronics comprising a synchronous demodulation device making it possible to demodulate the signal received by the reception element;
- le dispositif de détection comprend un générateur de signaux transmettant un signal carré ou sinusoïdal à l'élément d'émission et un signal carré au dispositif de démodulation de l'élément de réception ; etthe detection device comprises a signal generator transmitting a square or sinusoidal signal to the transmission element and a square signal to the demodulation device of the reception element; and
- le dispositif de détection comprend des moyens de calculs agencés pour déterminer la distance de l'objet par rapport au véhicule automobile en fonction de la capacité ou de la variation de capacité mesurées sur les deux paires d'éléments d'émission et de réception.the detection device comprises calculation means arranged to determine the distance of the object with respect to the motor vehicle as a function of the capacitance or the capacitance variation measured on the two pairs of transmission and reception elements.
L'invention concerne également un pare-choc de véhicule automobile comprenant un dispositif de détection tel que décrit ci-dessus. Selon d'autres caractéristiques du pare-choc :The invention also relates to a motor vehicle bumper comprising a detection device as described above. According to other features of the bumper:
- l'élément d'émission est fixé à une partie extrême transversale interne du pare-choc et l'élément de réception est disposé à l'autre partie extrême transversale interne du pare-choc ;the emission element is fastened to an internal transverse end portion of the bumper and the receiving element is arranged at the other internal transverse end portion of the bumper;
- l'élément d'émission et l'élément de réception sont noyés dans la matière du pare-choc ; etthe emission element and the receiving element are embedded in the material of the bumper; and
- les deuxièmes éléments d'émission et de réception sont disposés sous les premiers éléments d'émission et de réception du dispositif de détection ; etthe second transmission and reception elements are arranged under the first transmission and reception elements of the detection device; and
- le pare-choc comprend au moins une surface conductrice ou partiellement conductrice disposée sur le pare-choc et interposée entre l'élément d'émission et l'élément de réception du dispositif de détection, ladite surface étant reliée à la masse dudit dispositif de détection.the bumper comprises at least one conductive or partially conductive surface disposed on the bumper and interposed between the emission element and the receiving element of the detection device, said surface being connected to the ground of said detection device.
L'invention concerne également un véhicule automobile comprenant un pare-choc tel que décrit ci-dessus. Selon une autre caractéristique du véhicule, le véhicule automobile comprend un deuxième pare-choc tel que défini ci-dessus, l'un des pare-choc étant fixé à l'avant du véhicule automobile et l'autre pare-choc étant fixé à l'arrière dudit véhicule.The invention also relates to a motor vehicle comprising a bumper as described above. According to another characteristic of the vehicle, the motor vehicle comprises a second bumper as defined above, one of the bumper being attached to the front of the motor vehicle and the other bumper being attached to the vehicle. rear of said vehicle.
D'autres aspects et avantages de l'invention apparaîtront à la lecture de la description qui suit, donnée à titre d'exemple et faite en référence aux dessins annexés, dans lesquels : représentant schématiqueOther aspects and advantages of the invention will appear on reading the description which follows, given by way of example and with reference to the appended drawings, in which: schematic representative
- la Fig. 1 est une représentation schématique d'un pare-choc d'un véhicule automobile comprenant un dispositif de détection selon l'invention,FIG. 1 is a schematic representation of a bumper of a motor vehicle comprising a detection device according to the invention,
- la Fig. 2 est une représentation schématique d'un circuit électrique équivalent illustrant le fonctionnement du dispositif de détection selon l'invention lorsque aucun objet n'est présent dans la zone de détection,FIG. 2 is a schematic representation of an equivalent electrical circuit illustrating the operation of the detection device according to the invention when no object is present in the detection zone,
- la Fig. 3 est une représentation schématique d'un circuit électrique équivalent illustrant le fonctionnement du dispositif de détection selon l'invention, lorsqu'un objet est présent dans la zone de détection. Dans la description, les termes « transversal », « interne », « externe »,FIG. 3 is a schematic representation of an equivalent electrical circuit illustrating the operation of the detection device according to the invention, when an object is present in the detection zone. In the description, the terms "transversal", "internal", "external",
« au-dessus », « en dessous », etc. sont définis par rapport aux directions usuelles d'un véhicule automobile monté."Above", "below", etc. are defined with respect to the usual directions of a motor vehicle mounted.
En référence à la Fig. 1 , on décrit un pare-choc 1 destiné à être fixé à l'avant ou à l'arrière d'un véhicule automobile (non représenté). On notera que l'invention s'applique aussi bien à l'avant qu'à l'arrière du véhicule, le dispositif de détection de l'invention étant particulièrement avantageux lorsqu'il est installé à l'avant et à l'arrière du véhicule afin de fournir une plus grande zone de détection. Sur la Fig. 1 , la face interne 2 du pare-choc 1 est visible. Le dispositif de détection décrit ici peut également s'appliquer sur les côtés du véhicules, notamment dans les baguettes latérales, afin d'augmenter encore la zone de détection. La détection latérale est alors réalisée par le couplage et la combinaison des dispositifs avant, arrière et latéraux. Un dispositif de détection 4 est représenté de façon schématique sur la Fig. 1. Ce dispositif comprend un élément d'émission 6 d'un champ électrique, un élément de réception 8 d'un champ électrique et une électronique de commande 10, non représentés en détail. L'élément d'émission 6 est fixé, par exemple collé, à une partie extrême transversale 12 de la face interne 2 du pare-choc 1 , dans une zone supérieure de celle-ci. L'élément de réception 8 est fixé, par exemple collé, à l'autre partie extrême transversale 14 de la face interne 2 du pare-choc, dans une zone supérieure de celle-ci. Ces éléments 6 et 8 comprennent un matériau conducteur sur au moins une de leurs faces ou sur leurs deux faces. Les éléments 6 et 8 peuvent également être des surfaces conductrices appliquée en surface interne ou externe du pare-choc ou d'un autre élément du véhicule automobile. Les éléments 6 et 8 peuvent également être noyés dans la matière de la pièce à laquelle ils sont solidarisés. Selon un mode de réalisation, les éléments 6 et 8 sont chacun formés d'une pluralité d'éléments d'émission et de réception.With reference to FIG. 1, there is described a bumper 1 intended to be fixed to the front or rear of a motor vehicle (not shown). It should be noted that the invention applies both to the front and to the rear of the vehicle, the detection device of the invention being particularly advantageous when it is installed at the front and at the rear of the vehicle. vehicle to provide a larger detection area. In FIG. 1, the inner face 2 of the bumper 1 is visible. The detection device described here can also be applied to the sides of the vehicle, in particular in the side rods, in order to further increase the detection zone. Lateral detection is then achieved by coupling and combining the front, rear and side devices. A detection device 4 is shown schematically in FIG. 1. This device comprises a transmission element 6 of an electric field, a receiving element 8 of an electric field and a control electronics 10, not shown in detail. The emission element 6 is fixed, for example glued, to a transverse end portion 12 of the inner face 2 of the bumper 1, in an upper zone thereof. The receiving element 8 is fixed, for example bonded, to the other transverse end portion 14 of the inner face 2 of the bumper, in an upper zone thereof. These elements 6 and 8 comprise a conductive material on at least one of their faces or on both their faces. The elements 6 and 8 may also be conductive surfaces applied to the inner or outer surface of the bumper or other element of the motor vehicle. The elements 6 and 8 can also be embedded in the material of the part to which they are secured. According to one embodiment, the elements 6 and 8 are each formed of a plurality of transmission and reception elements.
L'élément d'émission 6 est relié à l'électronique de commande 10 de sorte à émettre un champ électrique qui sera ensuite reçu par l'élément récepteur 8. L'élément d'émission 6 est agencé pour émettre des signaux électriques modulés carrés ou sinusoïdaux. A cet effet, l'électronique de commande 10 comprend un générateur de signaux (non représenté) transmettant un signal carré ou sinusoïdale à l'élément d'émission 6. Le signal émis présente par exemple une tension d'une amplitude crête à crête sensiblement égale à 20V. Plus la surface du matériau conducteur de l'élément d'émission 6 est grande, plus la tension alternative du signal émis peut être réduite pour obtenir un résultat équivalent. Le signal émis par l'élément d'émission 6 fonctionne par exemple à une fréquence comprise entre 50 KHz et 200 KHz. On comprendra que d'autres fréquences puissent être utilisées en adaptant l'électronique de commande 10. La modulation du signal émis permet de distinguer celui-ci d'autres signaux environnants, par exemple provenant de dispositif de détection d'autres véhicules ou autre, afin que l'élément récepteur 8 traite le signal émis par l'élément d'émission 6 et pas un autre. On évite ainsi le traitement de signaux parasites.The emission element 6 is connected to the control electronics 10 so as to emit an electric field which will then be received by the receiver element 8. The emission element 6 is arranged to emit square modulated electrical signals or sinusoidal. For this purpose, the control electronics 10 comprises a signal generator (not shown) transmitting a square or sinusoidal signal to the transmission element 6. The emitted signal has, for example, a voltage of a substantially peak-to-peak amplitude. equal to 20V. The larger the surface of the conductive material of the emitting element 6, the lower the alternating voltage of the emitted signal can be to obtain an equivalent result. The signal emitted by the transmission element 6 operates for example at a frequency of between 50 KHz and 200 KHz. It will be understood that other frequencies can be used by adapting the control electronics 10. The modulation of the emitted signal makes it possible to distinguish it from other surrounding signals, for example coming from devices for detecting other vehicles or the like, so that the receiving element 8 processes the signal emitted by the transmitting element 6 and not another. This avoids the processing of spurious signals.
L'élément de réception 8 est agencé pour recevoir le signal électrique émis par l'élément d'émission 6 et pour démoduler celui-ci de façon synchrone ou pour transmettre le signal reçu à l'électronique de commande chargée de la démodulation synchrone afin d'extraire le signal du bruit environnant. A cet effet, afin de réaliser la démodulation synchrone, l'élément de réception 8 ou l'électronique de commande 10 comprend un dispositif de démodulation synchrone (non représenté), connu en soit, qui reçoit un signal carré du générateur de signal de l'électronique de commande 10. Le signal transmis au dispositif de démodulation présente la même fréquence que le signal transmis à l'élément émetteur, c'est-à-dire compris entre 50 KHz et 200 KHz selon l'exemple mentionné ci-dessus. De façon connue, l'élément de réception 8 est par exemple réalisé en utilisant un amplificateur inverseur associé à un circuit accordé. La sortie est reliée au dispositif de démodulation, lui-même relié à un filtre passe-bas. Le circuit accordé permet de limiter la bande passante de l'élément de réception à la fréquence d'intérêt du signal reçu. On élimine ainsi les grosses composantes de bruit qui pourraient perturber la mesure. Le dispositif de démodulation et le filtre passe-bas agissent comme un filtre à bande étroite. La démodulation synchrone permet d'obtenir un rapport signal sur bruit très important, ce qui permet de recevoir le signal émis même lorsque celui-ci est très faible. La distance de détection peut ainsi être augmentée, comme cela sera décrit ultérieurement.The receiving element 8 is arranged to receive the electrical signal emitted by the transmission element 6 and to demodulate it synchronously or to transmit the received signal to the control electronics in charge of the synchronous demodulation in order to extract the signal from the surrounding noise. For this purpose, in order to perform the synchronous demodulation, the reception element 8 or the control electronics 10 comprises a synchronous demodulation device (not shown), known in itself, which receives a square signal from the signal generator of the signal generator. Control electronics 10. The signal transmitted to the demodulation device has the same frequency as the signal transmitted to the transmitter element, that is to say between 50 KHz and 200 KHz according to the example mentioned above. In known manner, the receiving element 8 is for example made using an inverting amplifier associated with a tuned circuit. The output is connected to the demodulation device, itself connected to a low-pass filter. The tuned circuit limits the bandwidth of the receiving element to the frequency of interest of the received signal. This eliminates the large noise components that could disturb the measurement. The demodulation device and the low-pass filter act as a narrow-band filter. Synchronous demodulation makes it possible to obtain a very important signal-to-noise ratio, which makes it possible to receive the transmitted signal even when it is very weak. The detection distance can thus be increased, as will be described later.
L'électronique de commande 10 comprend des moyens de mesure de la capacité de couplage entre l'élément d'émission 6 et l'élément de réception 8 à partir du signal émis par l'élément d'émission 6 et du signal démoduler par le dispositif de démodulation synchrone.The control electronics 10 comprises means for measuring the coupling capacitance between the transmitting element 6 and the receiving element 8 from the signal emitted by the transmitting element 6 and the signal demodulating by the synchronous demodulation device.
En référence aux Fig. 2 et 3, le fonctionnement du dispositif décrit ci-dessus est le suivant : - lorsque aucun obstacle ne se trouve dans la zone de détection, c'est-à- dire la zone d'émission du champ électrique par l'élément d'émission, l'élément d'émission 6 et l'élément de réception 8 sont équivalents à deux capacités en série, respectivement Ci et C2. La capacité de couplage C, comme représentée sur la Fig. 2, entre l'élément d'émission 6 et l'élément de réception 8 présente alors une valeur fixe prédéfinie mesurée par les moyens de mesure.With reference to Figs. 2 and 3, the operation of the device described above is the following: - when no obstacle is in the detection zone, that is to say the emission zone of the electric field by the element of emission, the transmitting element 6 and the receiving element 8 are equivalent to two capacitors in series, respectively Ci and C 2 . The coupling capacitance C, as shown in FIG. 2, between the transmitting element 6 and the receiving element 8 then has a predefined fixed value measured by the measuring means.
- lorsqu'un obstacle pénètre dans la zone de détection, il est équivalent à une capacité C3 reliée d'une part à la terre et connectée d'autre part entre la capacité Ci de l'élément d'émission 6 et la capacité C2 de l'élément de réception 8, comme représenté sur la Fig. 3. Plus l'obstacle se rapproche du pare-choc 1 , plus C3 augmente, ce qui entraîne une variation de la capacité de couplage mesurée et permet de déterminer la présence d'un obstacle dans la zone de détection. Lorsque l'obstacle est en mouvement par rapport au véhicule automobile, la capacité de couplage mesurée varie. Lorsque l'obstacle est fixe par rapport au véhicule, la capacité de couplage est égale à une valeur différente de la valeur fixe prédéfinie mesurée lorsque aucun obstacle ne se trouve dans la zone de détection. Ainsi le dispositif permet de déterminer la présence d'un obstacle fixe ou en mouvement dans la zone de détection.when an obstacle enters the detection zone, it is equivalent to a capacitor C3 connected on the one hand to earth and connected on the other hand between the capacitor Ci of the emission element 6 and the capacitor C 2 the receiving element 8, as shown in FIG. 3. The more the obstacle approaches the bumper 1, the more C 3 increases, which causes a variation in the measured coupling capacity and makes it possible to determine the presence of an obstacle in the detection zone. When the obstacle is moving relative to the motor vehicle, the measured coupling capacity varies. When the obstacle is fixed relative to the vehicle, the coupling capacity is equal to a value different from the preset fixed value measured when no obstacle is in the detection zone. Thus, the device makes it possible to determine the presence of a fixed or moving obstacle in the detection zone.
Du fait de l'utilisation d'un élément d'émission et d'un élément de réception, il est possible d'alimenter l'élément d'émission à des tensions importantes, ce qui améliore la qualité du signal émis. De plus, l'utilisation de la démodulation synchrone permet d'isoler de façon optimale le signal reçu du bruit. Ces facteurs permettent d'obtenir une grande zone de détection s'étendant en avant ou en arrière du pare-choc selon que c'est un pare-choc avant ou un pare-choc arrière. On obtient également avantageusement une zone de détection s'étendant sur les côtés du pare-choc 1 avant ou arrière et sur les côtés latéraux du véhicule automobile. La zone de détection présente sensiblement une forme de demi- cercle. Par exemple, la détection d'un obstacle se fait jusqu'à 1 ,5 m autour du pare-choc. Selon un autre exemple, la détection se fait, selon les réglages, jusqu'à une distance de 4 m ou plus.Due to the use of a transmitting element and a receiving element, it is possible to supply the transmission element with large voltages, which improves the quality of the transmitted signal. In addition, the use of synchronous demodulation optimally isolates the signal received from the noise. These factors make it possible to obtain a large detection zone extending in front of or behind the bumper depending on whether it is a front bumper or a rear bumper. Advantageously, a detection zone extending on the sides of the front or rear bumper 1 and on the lateral sides of the motor vehicle is advantageously obtained. The detection zone has substantially a half-circle shape. For example, the detection of an obstacle is up to 1.5 m around the bumper. In another example, the detection is, depending on the settings, up to a distance of 4 m or more.
Selon un mode de réalisation, les éléments d'émission 6 et de réception 8 peuvent fonctionner en alternance au moyen d'un dispositif électronique de basculement. Ces éléments peuvent également fonctionner en éléments purement capacitifs.According to one embodiment, the transmission elements 6 and reception 8 can operate alternately by means of an electronic tilt device. These elements can also operate in purely capacitive elements.
Si l'élément d'émission 6 et l'élément de réception 8 décrits ci-dessus sont utilisés seuls, il est possible que les variations de niveau du sol par rapport au pare-choc soient considérés comme des obstacles entrant dans la zone de détection. Pour pallier cet inconvénient, le dispositif de détection 4 comprend une deuxième paire d'éléments d'émission 16 et de réception 18.If the transmitting element 6 and the receiving element 8 described above are used alone, it is possible that the variations of ground level with respect to the bumper are considered as obstacles entering the detection zone. . To overcome this drawback, the detection device 4 comprises a second pair of transmission elements 16 and reception elements 18.
Cette deuxième paire d'éléments 16 et 18 permet également de réaliser un calcul de la distance d'un objet dans la zone de détection et sa position. A cet effet, l'électronique de commande 10 comprend des moyens de calculs agencés pour déterminer la distance de l'obstacle par rapport au pare-choc 1 en fonction des signaux émis par les éléments d'émission 6 et 16 et reçus et par les éléments de réception 8 et 18. La deuxième paire d'éléments présente la même structure et fonctionne selon le même principe que l'élément d'émission 6 et l'élément de réception 8 décrits ci-dessus. Afin de permettre aux deux paires de fonctionner en même temps, le générateur de signal de l'électronique de commande transmet des signaux à une fréquence différente à la deuxième paire. Cette fréquence est également par exemple comprise entre 50 KHz et 200 KHz. Selon un exemple particulier, si l'élément d'émission 6 et l'élément de réception 8 fonctionnent à une fréquence de 80 KHz, l'élément d'émission 16 et l'élément de réception 18 fonctionnent à une fréquence de 170 KHz. Ainsi, chaque paire fonctionne indépendamment l'une de l'autre et les signaux ne sont pas mélangés. Les deuxièmes éléments d'émission 16 et de réception 18 sont disposés chacun à une partie extrême 12, 14 du pare-choc sous les éléments d'émission 6 et de réception 8. Cette deuxième paire permet de calibrer la première paire en effectuant la mesure des variations de niveau du sol de sorte que le conducteur ne soit pas informé de ces variations lors de la détermination de la présence d'un obstacle dans la zone de détection.This second pair of elements 16 and 18 also makes it possible to calculate the distance of an object in the detection zone and its position. In this Indeed, the control electronics 10 comprises calculation means arranged to determine the distance of the obstacle with respect to the bumper 1 as a function of the signals emitted by the transmission elements 6 and 16 and received and by the elements of FIG. reception 8 and 18. The second pair of elements has the same structure and operates according to the same principle as the transmission element 6 and the receiving element 8 described above. In order to allow both pairs to operate at the same time, the signal generator of the control electronics transmits signals at a different frequency to the second pair. This frequency is also for example between 50 KHz and 200 KHz. In a particular example, if the transmitting element 6 and the receiving element 8 operate at a frequency of 80 KHz, the transmitting element 16 and the receiving element 18 operate at a frequency of 170 KHz. Thus, each pair operates independently of each other and the signals are not mixed. The second transmission elements 16 and receiving 18 are each arranged at an end portion 12, 14 of the bumper under the transmission elements 6 and receiving 8. This second pair makes it possible to calibrate the first pair while carrying out the measurement. variations in the ground level so that the driver is not informed of these variations when determining the presence of an obstacle in the detection zone.
Lorsque le pare-choc est peint, une couche de « primer », ou « primaire » ou « apprêt », conductrice est déposée sur le pare-choc afin d'assurer une meilleur adhésion de la peinture ou une orientation particulière des particules de couleur. La présence de cette couche peut avoir pour conséquence que l'élément d'émission 6 transmet un signal à l'élément de réception 8 directement par la couche de primer sans pratiquement envoyer de signal vers l'extérieur du véhicule, ce qui peut détériorer les performances de détection du dispositif de détection 4. Pour pallier cet inconvénient, une surface conductrice ou partiellement conductrice 20 est disposée sur la face interne du pare-choc 1 entre l'élément d'émission 6 et l'élément de réception 8. Cette surface 20 est reliée à la masse de l'électronique de commande. La surface 20 s'étend par exemple sur toute la hauteur du pare-choc et est également interposée entre les deuxièmes éléments d'émission 16 et de réception 18. Les inventeurs ont constaté que cette surface 20 permet d'éliminer les effets de la couche de primer en empêchant une transmission directe du signal par cette couche. La surface 20 est par exemple réalisée par une encre ou une peinture conductrice déposée sur la face interne du pare-choc 1. Une feuille d'aluminium peut également être envisagée. Le dispositif de détection 4 décrit ci-dessus comprend un dispositif d'information du conducteur du véhicule informant celui-ci de la présence d'un obstacle en mouvement ou fixe autour du véhicule automobile. Ce dispositif peut également informer de la distance de cet obstacle par rapport au véhicule. Ce dispositif informe le conducteur en fonction du signal émis par le dispositif de détection, ce signal indiquant si une variation de la capacité de couplage ou un établissement d'une capacité d'une valeur différente se produit.When the bumper is painted, a layer of "primer", or "primer" or "primer", conductive is deposited on the bumper to ensure better adhesion of paint or a particular orientation of color particles . The presence of this layer may have the consequence that the transmission element 6 transmits a signal to the reception element 8 directly through the primer layer without substantially sending a signal to the outside of the vehicle, which can deteriorate the detection performance of the detection device 4. To overcome this drawback, a conductive or partially conductive surface 20 is disposed on the inner face of the bumper 1 between the emission element 6 and the receiving element 8. This surface 20 is connected to the ground of the control electronics. The surface 20 extends for example over the entire height of the bumper and is also interposed between the second transmission element 16 and receiving 18. The inventors have found that this surface 20 eliminates the effects of the primer layer by preventing direct transmission of the signal by this layer. The surface 20 is for example made by an ink or a conductive paint deposited on the inner face of the bumper 1. An aluminum foil can also be envisaged. The detection device 4 described above comprises an information device of the driver of the vehicle informing it of the presence of a moving or fixed obstacle around the motor vehicle. This device can also inform the distance of this obstacle relative to the vehicle. This device informs the driver as a function of the signal emitted by the detection device, this signal indicating whether a variation of the coupling capacity or an establishment of a capacity of a different value occurs.
On comprendra que les éléments d'émission et de réception peuvent également être disposés sur la face externe du pare-choc ou intégrés à l'intérieur de la matière du pare-choc comme décrit précédemment. Selon d'autres modes de réalisation, les éléments d'émission et de réception peuvent être placés sur d'autres parties du véhicule, comme les absorbeurs de choc, les baguettes latérales, les poutres, les bandeaux, etc.It will be appreciated that the transmitting and receiving elements may also be disposed on the outer face of the bumper or integrated within the bumper material as previously described. According to other embodiments, the transmitting and receiving elements can be placed on other parts of the vehicle, such as shock absorbers, side sticks, beams, bands, etc.
Le dispositif de détection décrit ci-dessus est particulièrement avantageux car il permet d'avoir une grande zone de détection autour du véhicule automobile, particulièrement si deux dispositifs sont utilisés, à savoir un à l'avant du véhicule et l'autre à l'arrière. De plus, il permet de détecter à la fois les obstacles en mouvement et les obstacles fixes. The detection device described above is particularly advantageous because it makes it possible to have a large detection zone around the motor vehicle, particularly if two devices are used, namely one at the front of the vehicle and the other at the vehicle. back. In addition, it can detect both moving obstacles and fixed obstacles.

Claims

REVENDICATIONS
1.- Dispositif de détection (4) de la présence d'un objet dans une zone de détection à proximité d'un véhicule automobile par la mesure d'une variation de capacité entraînée par la présence dudit objet, caractérisé en ce qu'il comprend un élément d'émission (6) d'un champ électrique, un élément de réception (8) d'un champ électrique disposé à distance de l'élément d'émission (6), et des moyens de mesure de la capacité de couplage entre l'élément d'émission (6) et l'élément de réception (8), l'élément d'émission (6) émettant un signal électrique qui est ensuite reçu par l'élément de réception (8) de sorte qu'une capacité de couplage d'une valeur prédéterminée est établie entre l'élément d'émission (6) et l'élément de réception (8) lorsque aucun objet n'est présent dans la zone de détection, une variation de la capacité de couplage entre l'élément d'émission (6) et l'élément de réception (8) indiquant le déplacement d'un objet dans la zone de détection et rétablissement d'une capacité d'une valeur différente de la valeur prédéterminée indiquant la présence d'un objet statique dans la zone de détection, un dispositif d'information du conducteur du véhicule informant ledit conducteur de la présence d'un obstacle en mouvement ou fixe autour du véhicule automobile.1.- Device for detecting (4) the presence of an object in a detection zone near a motor vehicle by measuring a variation in capacity caused by the presence of said object, characterized in that it comprises an element for emitting (6) an electric field, an element for receiving (8) an electric field arranged at a distance from the emitting element (6), and means for measuring the capacitance of coupling between the transmitting element (6) and the receiving element (8), the transmitting element (6) transmitting an electrical signal which is then received by the receiving element (8) so that 'a coupling capacitance of a predetermined value is established between the transmitting element (6) and the receiving element (8) when no object is present in the detection zone, a variation in the capacitance of coupling between the transmitting element (6) and the receiving element (8) indicating the movement of an object in the detection zone and reestablishing a capacitance of a value different from the predetermined value indicating the presence of a static object in the detection zone, a vehicle driver information device informing said driver of the presence of a moving or fixed obstacle around the motor vehicle.
2.- Dispositif de détection selon la revendication 1 , caractérisé en ce qu'il comprend un deuxième élément d'émission (16) et un deuxième élément de réception (18) d'un champ électrique, ladite paire d'éléments (16, 18) étant agencée pour calibrer le dispositif de détection (4) par rapport au sol et pour réaliser des mesures complémentaires avec les premiers éléments d'émission (6) et de réception (8).2.- Detection device according to claim 1, characterized in that it comprises a second transmitting element (16) and a second receiving element (18) of an electric field, said pair of elements (16, 18) being arranged to calibrate the detection device (4) relative to the ground and to carry out additional measurements with the first transmitting (6) and receiving (8) elements.
3.- Dispositif de détection selon la revendication 2, caractérisé en ce que les deux paires d'éléments d'émission et de réception (6, 8, 16, 18) sont agencées pour fonctionner à des fréquences différentes.3.- Detection device according to claim 2, characterized in that the two pairs of transmitting and receiving elements (6, 8, 16, 18) are arranged to operate at different frequencies.
4.- Dispositif de détection selon l'une quelconque des revendications 1 à 3, caractérisé en ce que l'élément d'émission (6, 16) émet un signal modulé, l'élément de réception (8, 18) ou une électronique de commande (10) comprenant un dispositif de démodulation synchrone permettant de démoduler le signal reçu par l'élément de réception (8, 18).4.- Detection device according to any one of claims 1 to 3, characterized in that the transmitting element (6, 16) emits a modulated signal, the receiving element (8, 18) or electronics control unit (10) comprising a synchronous demodulation device making it possible to demodulate the signal received by the reception element (8, 18).
5.- Dispositif de détection selon la revendication 4, caractérisé en ce qu'il comprend un générateur de signaux transmettant un signal carré ou sinusoïdal à l'élément d'émission (6, 16) et un signal carré au dispositif de démodulation de l'élément de réception (8, 18).5.- Detection device according to claim 4, characterized in that it comprises a signal generator transmitting a square or sinusoidal signal to the transmitting element (6, 16) and a square signal to the demodulation device of the receiving element (8, 18).
6.- Dispositif de détection selon l'une quelconque des revendications 2 à 5, caractérisé en ce qu'il comprend des moyens de calculs agencés pour déterminer la distance de l'objet par rapport au véhicule automobile en fonction de la capacité ou de la variation de capacité mesurées sur les deux paires d'éléments d'émission et de réception (6, 8, 16, 18).6.- Detection device according to any one of claims 2 to 5, characterized in that it comprises calculation means arranged to determine the distance of the object relative to the motor vehicle as a function of the capacity or the capacitance variation measured on the two pairs of transmitting and receiving elements (6, 8, 16, 18).
7.- Pare-choc (1 ) de véhicule automobile comprenant un dispositif de détection (4) de la présence d'un objet dans une zone de détection à proximité d'un véhicule automobile sur lequel le pare-choc (1 ) est monté, caractérisé en ce que le dispositif de détection (4) est selon l'une quelconque des revendications 1 à7.- Bumper (1) of a motor vehicle comprising a device (4) for detecting the presence of an object in a detection zone near a motor vehicle on which the bumper (1) is mounted , characterized in that the detection device (4) is according to any one of claims 1 to
6.6.
8.- Pare-choc selon la revendication 7, caractérisé en ce que l'élément d'émission (6) est fixé à une partie extrême transversale interne (12) du pare-choc et l'élément de réception est disposé à l'autre partie extrême transversale interne (14) du pare-choc.8.- Bumper according to claim 7, characterized in that the transmitting element (6) is fixed to an internal transverse end part (12) of the bumper and the receiving element is arranged at the other internal transverse end part (14) of the bumper.
9.- Pare-choc selon la revendication 7 ou 8, caractérisé en ce que l'élément d'émission (6) et l'élément de réception (8) sont noyés dans la matière du pare- choc. 9.- Bumper according to claim 7 or 8, characterized in that the transmitting element (6) and the receiving element (8) are embedded in the material of the bumper.
10.- Pare-choc selon l'une quelconque des revendications 7 à 9, lorsqu'elles dépendent de la revendication 2 ou 3, caractérisé en ce que les deuxièmes éléments d'émission et de réception (16, 18) sont disposés sous les premiers éléments d'émission et de réception (6, 8) du dispositif de détection.10.- Bumper according to any one of claims 7 to 9, when they depend on claim 2 or 3, characterized in that the second transmitting and receiving elements (16, 18) are arranged under the first transmitting and receiving elements (6, 8) of the detection device.
11.- Pare-choc selon l'une quelconque des revendications 7 à 10, caractérisé en ce qu'il comprend au moins une surface conductrice ou partiellement conductrice (20) disposée sur le pare-choc (1 ) et interposée entre l'élément d'émission (6) et l'élément de réception (8) du dispositif de détection (4), ladite surface (20) étant reliée à la masse dudit dispositif de détection (4).11.- Bumper according to any one of claims 7 to 10, characterized in that it comprises at least one conductive or partially conductive surface (20) disposed on the bumper (1) and interposed between the element transmitting element (6) and the receiving element (8) of the detection device (4), said surface (20) being connected to the ground of said detection device (4).
12.- Véhicule automobile comprenant au moins un pare-choc (1 ), caractérisé en ce que le pare-choc (1 ) est selon l'une quelconque des revendications 7 à 11.12.- Motor vehicle comprising at least one bumper (1), characterized in that the bumper (1) is according to any one of claims 7 to 11.
13.- Véhicule automobile selon la revendication 11 , caractérisé en ce qu'il comprend un deuxième pare-choc (1 ) selon l'une quelconque des revendications 7 à 10, l'un des pare-choc (1 ) étant fixé à l'avant du véhicule automobile et l'autre pare-choc étant fixé à l'arrière dudit véhicule. 13.- Motor vehicle according to claim 11, characterized in that it comprises a second bumper (1) according to any one of claims 7 to 10, one of the bumpers (1) being fixed to the front of the motor vehicle and the other bumper being fixed to the rear of said vehicle.
EP09772701A 2008-06-06 2009-06-05 Proximity detection device for a motor vehicle Withdrawn EP2310881A2 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FR0853781A FR2932281B1 (en) 2008-06-06 2008-06-06 PROXIMITY DETECTION DEVICE FOR MOTOR VEHICLE
PCT/FR2009/051063 WO2010001019A2 (en) 2008-06-06 2009-06-05 Proximity detection device for a motor vehicle

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EP (1) EP2310881A2 (en)
JP (1) JP2011526677A (en)
KR (1) KR101551263B1 (en)
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KR101551263B1 (en) 2015-09-08
KR20110033185A (en) 2011-03-30
FR2932281A1 (en) 2009-12-11
JP2011526677A (en) 2011-10-13
US20110156890A1 (en) 2011-06-30
WO2010001019A2 (en) 2010-01-07
FR2932281B1 (en) 2010-12-10
MX2010013417A (en) 2010-12-21
US8791801B2 (en) 2014-07-29
WO2010001019A3 (en) 2010-12-16
CN102099707A (en) 2011-06-15

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