Self-tracking method for sensors equipping the wheels of a vehicle

Abstract

The invention relates to a method for self-tracking of a data acquisition sensor equipping a wheel including a tire on a vehicle comprising a plurality of wheels (200) and being equipped with a system comprising an electronic unit (300) for a data acquisition sensor placed in each tire equipped with a radio-frequency transmitter for the purpose of the wireless transmission of said data to a central transmission and reception module (100) placed on the axle or frame of the vehicle, with the central transmission and reception module (100) receiving and decoding the information signals issued by the transmitters of each wheel, each electronic unit (300) being equipped to measure acceleration. The method is remarkable in that it consists of determining the front and rear of a tire by measuring the acceleration.

Claims

1. Self-tracking method for a data acquisition sensor equipping a wheel including a vehicle tire mounted on a vehicle, said vehicle comprising a plurality of wheels (200) said vehicle being equipped with a system comprising an electronic unit (300) for a data acquisition sensor, placed in each tire and equipped with a radio frequency transmitter, the radio frequency transmitter wirelessly transmitting data to a central transmission and reception module (100) placed on the axle or on the frame of the vehicle, the central transmission and reception module (100) receiving and decoding the information signals transmitted by the transmitters on each wheel, each electronic unit (300) being equipped to measure acceleration, said electronic units (300) comprising: a receiving unit receiving radio signals from the central transmission and reception module, the reception unit being capable of measuring the power of the radio signals received from the central transmission and reception module (100), for each electronic unit (300), the method including the following operations: measuring the power of the radio signals issued by the central transmission and reception module (100) and received by the electronic unit, distributing the received radio signals into the two following signal groups: a first group corresponding to the signals received chronologically between the high point and the low point, a second group corresponding to the signals received chronologically between the low point and the high point, such that if a majority of received signals is measured at high power between the high point and the low point, the wheel (200) containing the electronic unit (300) completing this measurement is arranged at the rear of the central transmission and reception module (100), if a majority of signals received is measured at low power between the high point and the low point, the wheel (200) containing the unit completing this measurement is arranged at the front of the central transmission and reception module (100); the method thus determining the front and rear of a tire by measuring the acceleration, the central transmission and reception module (100) being mounted such that when the central transmission and reception module (100) is fixed at the level of an axis of the axle a situation occurs where no majority appears in the signals measured, thus confirming that the wheel (200) containing the electronic unit (300) completing this measurement is placed at the height of the central transmission and reception module (100).

2. Method according to claim 1, CHARACTERIZED IN THAT it comprises causing the transmitter to transmit from the electronic unit (300) when the latter is located properly oriented in relation to the central transmission and reception module (100).

3. Method according to claim 1, CHARACTERIZED IN THAT it comprises causing the central transmission and reception module (100) to transmit to the electronic unit (300) reception device when the latter is well oriented in relation to the central transmission and reception module (100).

4. Method according to claim 1, CHARACTERIZED IN THAT it comprises avoiding causing the transmission units of the electronic units to simultaneously transmit to the electronic units (300) fixed to twinned wheels when they are located in the same zone.

5. Method according to claim 1, CHARACTERIZED IN THAT it comprises a high or low tilt sensor so as to determine in which angular section the unit is located.

6. Method according to claim 1, CHARACTERIZED IN THAT each electronic unit (300) comprises a visual benchmark (310) on its upper surface in order to comply with an orientation during its installation on the wheel.

7. Self-tracking method for a data acquisition sensor equipping a wheel including a vehicle tire, said vehicle comprising a plurality of wheels (200) and being equipped with a system comprising an electronic unit (300) for a data acquisition sensor, placed in each tire and equipped with a radio frequency transmitter for the purpose of wireless transmission of said data to a central transmission and reception module (100) placed on the axle or on the frame of the vehicle, the central transmission and reception module (100) receiving and decoding the information signals transmitted by the transmitters on each wheel, each electronic unit (300) being equipped to measure acceleration, the method including using radio signals in the low frequency spectrum (LF), that is, the portion of the radio electric frequency spectrum comprised between 30 kHz and 300 kHz, varying the power of the low frequency signals (LF); and determining the front and rear of a tire by measuring the acceleration.

8. Method according to claim 7, CHARACTERIZED IN THAT it comprises causing the transmitter to transmit from the electronic unit (300) when the latter is located properly oriented in relation to the central transmission and reception module (100).

9. Method according to claim 7, CHARACTERIZED IN THAT it comprises causing the central transmission and reception module (100) to transmit to the electronic unit (300) reception device when the latter is well oriented in relation to the central transmission and reception module (100).

10. Method according to claim 7, CHARACTERIZED IN THAT it comprises avoiding causing the transmission units of the electronic units to simultaneously transmit to the electronic units (300) fixed to twinned wheels when they are located in the same zone.

11. Method according to claim 7, CHARACTERIZED IN THAT it comprises a high or low tilt sensor so as to determine in which angular section the unit is located.

12. Method according to claim 7, CHARACTERIZED IN THAT each electronic unit (300) comprises a visual benchmark (310) on its upper surface in order to comply with an orientation during its installation on the wheel.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is a schematic drawing of a top view of a six-wheel vehicle in a situation where the method of the invention can be applied;

(2) FIG. 2 is a schematic drawing of a side view of a wheel positioned in front of a central module;

(3) FIG. 3 uses the drawing from FIG. 1 with a greater signal power;

(4) FIG. 4 uses the drawing from FIG. 1 with a lesser signal power;

(5) FIG. 5 is a flow chart illustrating a means for the embodiment of the method of the invention;

(6) FIG. 6 is a schematic drawing of a perspective view of a means for the embodiment of an electronic unit according to the invention;

(7) FIGS. 7a, 7b, 7c and 7d are schematic drawings from an upper view of four different vehicles illustrating the disposition of the reception modules according to the arrangement of the wheels;

(8) FIG. 8 is a schematic drawing from an upper view illustrating the positioning of the sensor units in a vehicle configuration for a vehicle with twinned wheels;

(9) FIG. 9 is a schematic drawing of sinusoidal curves followed by the acceleration measurements.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

(10) As illustrated by the drawing in FIG. 1, a monitoring system for the pressure and/or temperature of tires equips a vehicle represented here in view from above by its six wheels. The system comprising an electronic unit (not illustrated), placed in each tire and equipped with a radio frequency transmitter for the purpose of wireless transmission of said data to a central module 100 transmission and reception module placed on the axle or on the frame of the vehicle. The central transmission and reception module 100 receives and decodes the information signals transmitted by the transmitters on each wheel. Each electronic unit (not illustrated) being equipped to measure acceleration.

(11) FIG. 2 illustrates a wheel 200 placed in front of the central module 100. As explained above, the measurement of acceleration by the electronic unit 300 during rotation (arrow F1) of the wheel 200, namely, during movement of the vehicle, makes it possible to determine two points:

(12) the high point of the wheel corresponding to an acceleration in Z minimal, designated Z min.

(13) the low point of the wheel corresponding to an acceleration in Z maximal, designated Z max.

(14) This determination of high and low points makes it possible to divide the wheel 200, into a forward part and a rear part. As illustrated, the central module 100 transmits in LF.

(15) Each electronic unit 300 comprises:

(16) a receiving unit (not illustrated) receiving radio signals from the central transmission and reception module,

(17) the reception unit being capable of measuring the power of the radio signals received from the central transmission and reception module 100.

(18) According to the invention, each electronic unit 300 implements the following operations: it measures the power of LF radio signals sent by the central transmission and reception module 100. it distributes the received radio signals into the two following signal groups:

(19) first group corresponding to the signals received chronologically between the high point (Z min) and the low point (Z max),

(20) second group corresponding to the signals received chronologically between the low point (Z max) and the high point (Z min). These high and low points are easily found by reading the curve in FIG. 9 where the high and low points of the curves respectively correspond to the minimum and maximum accelerations measured. We also understand that the operation of the tilt sensors would correspond to the direct detection of a single high or low point of accelerations without taking intermediate measurements.

(21) By comparing said groups, and learning the direction of progress F2 of the vehicle,

(22) if a majority of received signals is measured at high power between the high point and the low point, the wheel containing the unit completing this measurement is arranged at the rear of the central module, like the wheels 200 in FIG. 1,

(23) if, as in the example illustrated in FIG. 2, a majority of signals received is measured at low power between the high point and the low point, the wheel 200 containing the unit 300 completing this measurement is arranged at the front of the central module 100.

(24) We also understand that, if no majority of signals is established, the wheels in question are those designated 200 (cf. FIG. 1) located at the height of the central module 100. According to the invention, the central module 100 is positioned at the height of the wheel axis for this purpose.

(25) The part of the wheel between the high point and the low point where signal powers are measured, is used here as a reference. With the understanding that another part could be used. It is also possible to use the high power as a reference and to determine which part of the wheel receives the most high-power signals.

(26) Automatic determination of the front or rear position of the wheels in relation to the central module 100 is used in self-tracking of the wheels by associating it with a left/right localization like those known in the prior art.

(27) Another operation making it possible to refine the front and rear and/or that of left/right localization consists of varying the power of the LF signal issued by the central module 100, as illustrated in the drawings of FIGS. 3 and 4.

(28) The transmission power may also be modulated as a function of the size of the vehicle and of the distance between the wheels.

(29) According to a preferred embodiment, the reception module is positioned centered on the frame as illustrated in the drawings of FIGS. 7a, 7b, 7c and 7d. Depending on whether the wheels are located on an upper or lower radius of two meters in relation to the reception module 100, configurations can vary.

(30) The drawings in FIGS. 7a, 7c and 7d illustrate the locations of wheels installed at least 2 meters from the reception module 100. The drawing in FIG. 7b illustrates a location of wheels exceeding the radius of two meters and thus requiring the presence of a second reception module 100.

(31) According to a preferred, but not limitative, means of embodiment, the method of self-tracking of the wheels of a vehicle such as a truck is done according to the following steps: installation of electronic units on the wheels of the truck, configuration (by using a portable electronic module or with a CAN connection) and installation on a central module on the truck according to a position chosen in relation to the positioning of the vehicle's wheels, when the electronic unit measures a radial acceleration greater than 4 g, lateral localization is implemented (by means of a technical solution known in the prior art), the central module receives data regarding the lateral position of the sensor of the electronic unit (information contained in the message transmitted in RF), the central module probes with a full power LF signal in order to select only the sensors mounted on the vehicle, the central module completes the front/rear localization by LF on the electronic units' sensors according to the flow chart illustrated by the drawing in FIG. 5, the central module memorizes the localizations of the electronic units' sensors.

(32) FIG. 6 illustrates a means of embodiment of an electronic unit making it possible to implement the method of the invention. As illustrated, said unit 300 comprises, on its upper face, an arrow 310 which must always be positioned to indicate the same side of the wheel, namely, the flange side.

(33) Thus, as illustrated in the drawing of FIG. 8, the sensors of the two wheels positioned at the same extremity of the axle are then disposed opposite each other. By systematically orienting the electronic units in the same way as the sensors in the wheels, they are found opposite each other when the wheels are twinned. By knowing the rotation direction of the wheels, it is then possible to differentiate the signals sent from the two twinned wheels.

(34) It is understood that the method and the device, which have just been described and shown hereinabove, were described and shown for the purposes of divulgation, rather than as a limitation. Of course, various arrangements, modifications and improvements can be made to the example hereinabove, without however leaving the scope of the invention.