Method for detecting an intruder object under a motor vehicle

Abstract

The invention relates to a method for detecting an intruder object under a vehicle (10) equipped with a tire pressure monitoring system comprising at least two wheel units (16a, 16b) and a central unit (12) comprising a communication device (24) for communicating with each of said wheel units, characterized in that it comprises a probing step comprising a transmission phase which consists in transmitting at least one probe signal from the first wheel unit (16a) to the second wheel unit (16b) through a transmission channel (C1), and an analysis step which consists in comparing and measuring differences in properties between said probe signal received by the second wheel unit (16b) and a previously defined reference signal, and in determining whether said measured differences are characteristic of the presence of an intruder object present on said transmission channel used by said probe signal. Figure for abstract: Figure 1

Description

Title of the invention: Method for detecting an intruder object under a motor vehicle Technical field

[0001] The present patent application relates to a method for detecting an intruding object under a motor vehicle which is equipped with a tire pressure monitoring system. Prior art

[0002] For safety purposes, it is known to equip a motor vehicle with a monitoring system known as "TPMS", the English acronym for "Tyre Pressure Monitoring System", or in French "Tire Pressure Monitoring System".

[0003] Such a monitoring system, which is for example described in document FR3045498, generally comprises a central computing unit mounted on the vehicle and wheel units which each equip an associated wheel of the vehicle.

[0004] The central unit includes an electronic calculator known as “ECU”, the English acronym for “Electronic Control Unit”.

[0005] Also, the vehicle's central unit is equipped with a radio receiver adapted to communicate with each wheel unit.

[0006] Each wheel unit is responsible for regularly acquiring the physical quantities representative of operating parameters of the associated wheel, in particular to detect an anomaly of the associated wheel.

[0007] Also, each wheel unit transmits, to the central unit of the vehicle, messages comprising pressure, temperature and acceleration data of the associated wheel, as well as an identification code of the transmitting wheel unit.

[0008] For this purpose, each wheel unit comprises a tire inflation pressure sensor, a temperature sensor, an accelerometer and a radio transmitter.

[0009] Furthermore, each wheel unit is equipped with a battery for power supply and a microcontroller comprising a data storage memory and a microprocessor.

[0010] Upon receipt of this data by the vehicle's central unit, in the event of a significant deviation in pressure from the pressure recommended by the manufacturer, the TPMS system will warn the driver of the vehicle of under-inflation of one of the wheels, by means of an alert message displayed on the vehicle's dashboard, for example.

[0011] A technical problem that remains is the detection of the presence of an intruding object present under the motor vehicle.

[0012] The intruding object is, for example, a living being, and more particularly an animal, which has slipped under the vehicle before or after the driver gets behind the wheel.

[0013] However, when starting the motor vehicle, the driver is not able to know if there is an intruder under the car.

[0014] Even if a visual check is carried out by the driver, this is not sufficient because there is a latency time between the moment the check is carried out and the moment the vehicle starts, during which time an animal can place itself under the vehicle.

[0015] Similarly, with regard to electric motor vehicles which are equipped with a battery recharged by induction, we seek to avoid the presence of an intruding object under the vehicle to avoid harming this object if it is a living being.

[0016] Indeed, exposure to electromagnetic fields can have undesirable biological effects on living beings.

[0017] Also, we seek to avoid the presence of an intruding object which is arranged under the electric vehicle and which is interposed between the induction charger and the vehicle, to avoid disturbing the recharging of the vehicle by induction. Statement of the invention

[0018] The aim of the present invention is to solve the problem of detecting the presence of an intruder object under a motor vehicle, in particular when starting the vehicle or when inductively charging the vehicle.

[0019] This objective, as well as others which will appear on reading the following description, is achieved with a method for detecting an intruding object under a motor vehicle which is equipped with a tire pressure monitoring system, said system comprising at least: • a first wheel unit which equips a first wheel of the motor vehicle and which comprises a first radio communication device comprising a transmitter and a receiver, • a second wheel unit which equips a second wheel of the motor vehicle and which comprises a second communication device comprising a radio transmitter and receiver, and • a central unit which comprises a computer and a communication device adapted to communicate with each of said wheel units, characterized in that it comprises at least: • a probing step which successively comprises a transmission phase which consists of emitting at least one probe signal from the first wheel unit to the second wheel unit, through a transmission channel which extends between the first wheel unit and the second wheel unit, then a phase of reception of said probe signal by the second wheel unit, and • an analysis step which consists of comparing and measuring differences in properties between said probe signal received by the second wheel unit and a previously defined reference signal, and determining whether said measured differences are characteristic of the presence of an intruder object present on said transmission channel used by said probe signal.

[0020] Thus, the present invention makes it possible to detect an intruding object present under the vehicle without having to get out of the vehicle to check visually.

[0021] According to other optional characteristics of the invention, taken alone or in combination:

[0022] - the properties measured during the analysis step concern the variation of power as a function of the probe signal frequency;

[0023] - the properties measured during the analysis step concern the variation of phase as a function of the frequency of the probe signal;

[0024] - the method comprises a step of determining the reference signal which is carried out at least once before the probing step and which successively comprises a transmission phase which consists of transmitting the probe signal from the first wheel unit to the second wheel unit through said transmission channel, then a phase of receiving and recording the probe signal received by the second wheel unit as being said reference signal;

[0025] - the communication devices of each wheel unit and the central unit function operate according to the Bluetooth® standard. Indeed, the Bluetooth® standard allows two-way exchange between two devices;

[0026] - in a minimal example of embodiment of the invention, the first wheel unit and the second wheel unit are arranged diagonally on the motor vehicle, so that the transmission channel between them passes through the middle of the vehicle;

[0027] - the motor vehicle comprises four wheel units which each equip a wheel of the vehicle, the transmission phase of the probing step consisting of transmitting at least one probe signal from each wheel unit to each of the three other wheel units, and the analysis step consisting of comparing and measuring differences in properties between the probe signal received by each wheel unit with a previously defined associated reference signal, and determining whether said measured differences are characteristic of the presence of an intruder object present on the transmission channel used by the probe signal concerned;

[0028] - the method is executed by the motor vehicle when a procedure of starting of said vehicle is detected;

[0029] - said motor vehicle is an electric motor vehicle powered by a battery, said method being performed when an induction charging procedure battery is detected.

[0030] The invention also relates to a motor vehicle which comprises at least one central unit and two wheel units duly programmed to implement the method described above. Brief description of the drawings

[0031] Other characteristics, aims and advantages of the invention will appear on reading the detailed description which follows for the understanding of which reference will be made to the appended drawings in which:

[0032] [Fig-1] [Fig.l] is a schematic top view of a motor vehicle equipped with a central unit and four wheel units duly programmed to implement the method according to the invention;

[0033] [Fig.2] [Fig.2] is a graph with the abscissa axis representing the communication channels graduated in mega Hertz (MHz) and the ordinate axis graduated in decibel (dB), representative of the variation in power as a function of the frequency of the reference signal received by the second wheel unit and emitted by the first wheel unit;

[0034] [Fig.3] [Fig.3] is a graph similar to that of [Fig.2], representative of the variation in power as a function of the frequency of the probe signal received by the second wheel unit and emitted by the first wheel unit;

[0035] [Fig.4] [Fig.4] is a graph with the abscissa axis representing the communication channels graduated in mega Hertz (MHz) and the ordinate axis graduated in degrees of angle (°), representative of the phase variation as a function of the frequency of the reference signal received by the second wheel unit and emitted by the first wheel unit;

[0036] [Fig.5] [Fig.5] is a graph similar to that of [Fig.4], representative of the phase variation as a function of the frequency of the probe signal received by the second wheel unit and emitted by the first wheel unit;

[0037] [Fig.6] [Fig.6] is a flowchart which illustrates the sequence of steps of the method according to the invention.

[0038] Throughout these figures, identical or similar elements are identified by identical or similar reference signs. Description of the embodiments

[0039] [Fig.l] schematically shows a motor vehicle 10 according to the invention, which comprises a central unit 12 and four wheels 14a, 14b, 14c, 14d which are each equipped with a wheel unit 16a, 16b, 16c, 16d respectively.

[0040] In order not to make the description too long, only the first wheel unit 16a is described below, the four wheel units 16a, 16b, 16c, 16d having a similar design and operation.

[0041] The wheel unit 16a belongs to a tire pressure monitoring system matics known by the English acronym “TPMS”, for “Tyre Pressure Monitoring System”.

[0042] The wheel unit 16a comprises a housing which contains a microcontroller equipped with a processor, a battery, a memory and a set of sensors dedicated to measuring operating parameters of the wheel unit 16a.

[0043] This set of sensors comprises for example a temperature sensor and a pressure sensor capable of measuring the inflation pressure of the tire of the associated wheel 14a.

[0044] The measurements taken by the sensors can be transmitted to the central unit 12 of the motor vehicle 10.

[0045] For this purpose, the wheel unit 16a comprises a radio communication device 18 which comprises a transmitter 20 and a receiver 22.

[0046] Similarly, the central unit 12 comprises a radio communication device 24 which is adapted to communicate with each of the wheel units 16a, 16b, 16c, 16d and which comprises a transmitter 26 and a receiver 28.

[0047] According to an exemplary embodiment, the communication device 18 of each wheel unit 16a, 16b, 16c, 16d and the communication device 24 of the central unit 12 operate according to the Bluetooth® standard which allows a short-distance bidirectional exchange of data using radio waves.

[0048] In addition, the central unit 12 of the motor vehicle 10 comprises an electronic computer 30 and a memory 32.

[0049] In this exemplary embodiment of the invention, the motor vehicle 10 is an electric motor vehicle powered by a battery (not shown).

[0050] The invention relates to a method for detecting an intruder object located under the motor vehicle 10, the sequence of steps of which is illustrated in [Fig.6].

[0051] The term "intruding object" means both a living being, such as an animal, and an inanimate object.

[0052] The method according to the invention comprises a first probing step E1 which successively comprises a transmission phase followed by a reception phase.

[0053] The transmission phase consists of transmitting a probe signal successively from each wheel unit 16a, 16b, 16c, 16d, to each of the three other wheel units 16a, 16b, 16c, 16d.

[0054] The reception phase consists of receiving the probe signal emitted successively by each wheel unit 16a, 16b, 16c, 16d, by each of the three other wheel units 16a, 16b, 16c, 16d.

[0055] The wheel units 16a, 16b, 16c, 16d are connected two by two by a transmission channel through which the signals are transmitted.

[0056] The term "transmission channel" refers to the path through which data are transmitted between a transmitter and a receiver.

[0057] In the context of a Bluetooth® type communication according to the invention, the transmission channel is the path by which the radio signals pass between the connected wheel units 16a, 16b, 16c, 16d.

[0058] As can be seen in [Fig. 1], a first channel C1 extends between the first wheel unit 16a and the second wheel unit 16b, a second channel C2 extends between the first wheel unit 16a and the third wheel unit 16c, a third channel C3 extends between the first wheel unit 16a and the fourth wheel unit 16d, a fourth channel C4 extends between the second wheel unit 16b and the fourth wheel unit 16d, a fifth channel C5 extends between the second wheel unit 16b and the third wheel unit 16c and a sixth channel C6 extends between the third wheel unit 16c and the fourth wheel unit 16d.

[0059] According to a preferred embodiment of the invention, the first probing step E1 consists of executing a “channel probing” function which is known by the English terminology “channel sounding” and which is specific to Bluetooth® technology.

[0060] The "channel sounding" function is generally implemented to measure the quality and conditions of the transmission channel, including interference, noise and other parameters.

[0061] The first probing step E1 is followed by a second analysis step E2 which consists of comparing and measuring differences in properties between the probe signal received by each wheel unit 16a, 16b, 16c, 16d with a previously defined reference signal which is associated with each receiving wheel unit 16a, 16b, 16c, 16d.

[0062] This second analysis step E2 is carried out by the computer 30 of the central unit 12.

[0063] For this purpose, the probe signal to be analyzed is transmitted by radio communication to the central unit 12, which analyzes said probe signal with the corresponding reference signal which is recorded in the memory 32 of the central unit 12.

[0064] For example, the probe signal received by the second wheel unit 16b and sent from the first wheel unit 16a through the first transmission channel Cl, is compared to the reference signal which is associated with this pair of wheel units 16a, 16b and with the associated channel Cl.

[0065] Each reference signal is a signal which is characteristic of an “idle” transmission between the transmitter of a wheel unit 16a, 16b, 16c, 16d and the receiver of another wheel unit 16a, 16b, 16c, 16d, that is to say when the transmission channel used by the signal is not disturbed by the presence of an intruder object.

[0066] Indeed, the transmission channel can be affected by various factors such as radio interference, electromagnetic noise and physical obstacles.

[0067] The analysis step E2 makes it possible to determine whether the differences measured between the probe signal received by the wheel unit 16a, 16b, 16c, 16d concerned with the associated reference signal are characteristic of the presence of an intruder object present on the transmission channel used.

[0068] According to an exemplary embodiment of the invention, the properties measured during the analysis step E2 relate to the variation in power as a function of the frequency of the probe signal being received.

[0069] As an example, [Fig.2] shows a graph representing the variation in power as a function of the frequency of the reference signal received by the second wheel unit 16b, and emitted by the first wheel unit 16a.

[0070] Also, [Fig.3] represents a graph similar to that of [Fig.2], representative of the variation in power as a function of the frequency of the probe signal received by the second wheel unit 16b, and emitted by the first wheel unit 16a.

[0071] Significant differences can be observed between the graph in [Fig.2] and that in [Fig.3], differences which are characteristic of the presence of an intruder object present on the transmission channel Cl used.

[0072] The properties measured during the analysis step E2 also concern the phase variation as a function of the frequency of the probe signal in reception, we speak of phase signature.

[0073] As an example, [Fig.4] shows a graph representing the phase variation as a function of the frequency of the reference signal received by the second wheel unit 16b, and emitted by the first wheel unit 16a.

[0074] In other words, the graph of [Fig.4] represents the phase signature of the reference signal received by the second wheel unit 16b.

[0075] In this exemplary embodiment, the Bluetooth® communication uses a frequency band of 80 mega Hertz between 2402 and 2480 mega Hertz, or forty channels spaced two mega Hertz apart.

[0076] As a non-limiting example, it will be noted that the communication devices 18, 24 can operate according to other technologies which make it possible to have information on the transmission channel in amplitude and phase, for example in Wifi or in Ultra Wide Band UWB.

[0077] Also, [Fig.5] represents a graph similar to that of [Fig.4], representative of the phase variation as a function of the frequency of the probe signal received by the second wheel unit 16b, and emitted by the first wheel unit 16a.

[0078] Significant differences can be observed between the graph in [Fig.4] and that in [Fig.5], differences which are characteristic of the presence of an intruder object present on the transmission channel Cl used.

[0079] Preferably, the method according to the invention is executed by the motor vehicle 10 when a vehicle start procedure is detected.

[0080] Thus, if during the analysis step E2 an intruder object is detected, the starting of the motor vehicle 10 is prevented and / or an alert message is displayed on the dashboard of the vehicle.

[0081] Similarly, the method according to the invention can be executed by the motor vehicle 10 when an induction charging procedure of the vehicle battery is detected, or during the induction charging procedure.

[0082] If during the analysis step E2 an intruder object is detected, the recharging of the motor vehicle 10 is prevented or suspended, and / or an alert message is displayed on the dashboard of the vehicle.

[0083] Finally, the method according to the invention comprises a step of determining the reference signal E0 which is carried out before the probing step E1.

[0084] For example, the step of determining the reference signal E0 is carried out in the factory when the motor vehicle 10 is equipped with its four wheel units 16a, 16b, 16c, 16d.

[0085] However, the step of determining the reference signal E0 can be carried out during the life of the motor vehicle 10, for example when one or more wheel units 16a, 16b, 16c, 16d are replaced.

[0086] The step of determining the reference signal E0 comprises a transmission phase which consists of transmitting the probe signal successively from each wheel unit 16a, 16b, 16c, 16d, to each of the three other wheel units 16a, 16b, 16c, 16d.

[0087] Also, the step of determining the reference signal E0 comprises a reception phase consisting of the reception of the probe signal emitted successively by each wheel unit 16a, 16b, 16c, 16d, by each of the three other wheel units 16a, 16b, 16c, 16d.

[0088] This reception phase is followed by a phase of recording the received probe signal as being the reference signal, and of associating the reference signal with the pair of wheel units concerned.

[0089] Of course, the step of determining the reference signal E0 is carried out when no intruding object is present under the motor vehicle 10.

[0090] Thus, the method according to the invention makes it possible to detect the presence of an intruding object present under the motor vehicle 10 by scanning a large area between the four wheel units 16a, 16b, 16c, 16d.

[0091] By way of non-limiting example, in a minimal configuration of the method according to the invention, the method is carried out between only two wheel units 16a, 16b which are arranged diagonally, so that the transmission channel C1 which separates them passes through the middle of the motor vehicle 10.

[0092] Naturally, the invention is described in the foregoing by way of example. It is it is understood that a person skilled in the art is able to carry out different variant embodiments of the invention without departing from the scope of the invention.

Claims

Claims

1. Method for detecting an intruder object under a motor vehicle (10) which is equipped with a tire pressure monitoring system, said system comprising at least: • a first wheel unit (16a) which equips a first wheel (14a) of the motor vehicle (10) and which comprises a first radio communication device (18) comprising a transmitter (20) and a receiver (22), • a second wheel unit (16b) which equips a second wheel (14b) of the motor vehicle (10) and which comprises a second communication device comprising a transmitter and a radio receiver, and • a central unit (12) which comprises a computer (30) and a communication device (24) adapted to communicate with each of said wheel units (16a, 16b),characterized in that it comprises at least: • a probing step (El) which successively comprises a transmission phase which consists of transmitting at least one probe signal from the first wheel unit (16a) to the second wheel unit (16b), through a transmission channel (Cl) which extends between the first wheel unit (16a) and the second wheel unit (16b), then a phase of reception of said probe signal by the second wheel unit (16b), and • an analysis step (E2) which consists of comparing and measuring differences in properties between said probe signal received by the second wheel unit (16b) and a previously defined reference signal, and determining whether said measured differences are characteristic of the presence of an intruder object present on said transmission channel (Cl) used by said probe signal.,

2. Method for detecting an intruder object according to claim 1, characterized in that the properties measured during the analysis step (E2) relate to the variation in power as a function of the frequency of the probe signal.

3. Method for detecting an intruder object according to any one of preceding claims, characterized in that the properties measured during the analysis step (E2) relate to the phase variation as a function of the frequency of the probe signal.

4. Method for detecting an intruder object according to any one of the preceding claims, characterized in that it comprises a step of determining the reference signal (EO) which is carried out at least once before the probing step (El) and which successively comprises a transmission phase which consists of transmitting the probe signal from the first wheel unit (16a) to the second wheel unit (16b) through said transmission channel (Cl), then a phase of receiving and recording the probe signal received by the second wheel unit (16b) as being said reference signal.

5. Method for detecting an intruder object according to any one of the preceding claims, characterized in that the communication devices (18) of each wheel unit (16a, 16b) and of the central unit (12) operate according to the Bluetooth® standard.

6. Method for detecting an intruder object according to any one of the preceding claims, characterized in that the first wheel unit (16a) and the second wheel unit (16b) are arranged diagonally on the motor vehicle (10), so that the transmission channel (Cl) which separates them passes through the middle of the vehicle.

7. Method for detecting an intruder object according to any one of the preceding claims, characterized in that the motor vehicle (10) comprises four wheel units (16a, 16b, 16c, 16d) which each equip a wheel (14a, 14b, 14c, 14d) of the vehicle, the transmission phase of the probing step (El) consisting of transmitting at least one probe signal from each wheel unit (16a, 16b, 16c, 16d) to each of the three other wheel units, and the analysis step (E2) consisting of comparing and measuring differences in properties between the probe signal received by each wheel unit (16a, 16b, 16c, 16d) with a previously defined associated reference signal, and determining whether said measured differences are characteristic of the presence of an intruder object present on the channel (C1, C2, C3, C4, C5, C6) of transmission taken by the probe signal concerned.

8. Method for detecting an intruder object according to any one of the preceding claims, characterized in that it is executed by the motor vehicle (10) when a starting procedure of said vehicle is detected.

9. Method for detecting an intruder object according to any one of the preceding claims, characterized in that said motor vehicle (10) is an electric motor vehicle powered by a battery, said method being executed when an induction charging procedure of the battery is detected.

10. Motor vehicle (10) which comprises at least one central unit (12) and two wheel units (16a, 16b) duly programmed to implement the method according to any one of claims 1 to 9.

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