METHOD FOR DETERMINING THE ANGULAR POSITION OF AN ELECTRONIC MODULE FIXED TO THE INNER FACE OF THE TREAD OF A TIRE

• US 20140007683A1
• Filed: 07/08/2013
• Published: 01/09/2014
• Est. Priority Date: 07/06/2012
• Status: Active Grant

• Current Assignee: Continental Automotive France (Continental AG), Continental Automotive GmbH (Continental AG)
• Original Assignee: Continental Automotive GmbH (Continental AG), Continental Automotive Incorporated (Continental AG)
• Inventors: GUINART, Nicolas, BOISSET, Jean-Philippe
• Granted Patent: US 9,632,106 B2
• Time in Patent Office: Days
• US Class Current: 73/514.02
• CPC Class Codes: B60C 23/0416 allocating a corresponding wheel position on vehicle, e.g. front/left or rear/right
• CPC Class Codes: B60C 23/0459 self triggered by motion sensor
• CPC Class Codes: B60C 23/0489 for detecting the actual angular position of the monitoring device while the wheel is turning
• CPC Class Codes: B60C 23/0493 for attachment on the tyre
• CPC Class Codes: B60C 23/064 comprising tyre mounted deformation sensors, e.g. to determine road contact area
• CPC Class Codes: G01P 15/165 for measuring angular accelerations

Abstract

Method for determining the angular position of an electronic module fixed to the inner face of the tread of a tire fitted to a wheel of a vehicle. A sensor for measuring the radial acceleration of the wheel is integrated into the electronic module, measuring at least one measurement of the radial acceleration for determining the value of the period of revolution of the wheel, and detecting a variation of the radial acceleration representative of a position of the electronic module contacting the ground, the position of the electronic module in which the variation is detected is assigned the origin function of a frame of reference defined by the origin and a reference unit formed by an angular sector whose length is substantially shorter than the mean length of the footprint of the grounded tire, and the angular positions of the electronic module in the frame of reference are determined.

Claims

1. Method for determining, during the rotation of a wheel (2) of a vehicle (1) fitted with a tire (4), the angular position of an electronic module (5) fixed to the inner face of the tread (4a) of said tire, characterized in that:

a sensor (12) for measuring the radial acceleration of the wheel (2) is integrated into the electronic module (5),

at least one measurement of the radial acceleration is made in order to determine the value T of the period of revolution of the wheel (2),

the radial acceleration of the wheel (2) is measured with a predetermined sampling period adapted to detect a variation of said radial acceleration representative of a position of the electronic module (5) in contact with the ground,

the position of the electronic module (5) in which a variation of the radial acceleration is detected is assigned the origin function So of a frame of reference defined by said origin and a reference unit formed by an angular sector Su, called the unit sector, whose length is at least substantially shorter than the mean length of the footprint Lfp of the tire (4) on the ground,

and the angular positions of the electronic module (5) are determined in the frame of reference (So, Su) defined by the origin So and the unit sector Su.

2. Method according to claim 1, characterized in that, in order to detect the origin point So, the radial acceleration of the wheel (2) is measured with a sampling period equal to T/x, in such a way that said origin point is the position of an origin sector So having the same length as the unit sector Su.

3. Method according to claim 1, characterized in that the measurements of radial acceleration are made with a sampling period T/x equal to T/20.

4. Method according to claim 1, characterized in that the frame of reference defined by the origin sector So and the unit sector Su is used for the determination of the angular positions of the electronic module (5) in which the transmission of signals between said electronic module and a central unit (14) on board the vehicle (1) is commanded.

5. Method according to claim 1, characterized in that a series of measurements are made in the origin sector So, after at least one revolution of the wheel (2) following the detection of said origin sector, with a sampling frequency adapted to allow the subsequent detection of a variation in radial acceleration corresponding to a falling edge followed by a variation in radial acceleration corresponding to a rising edge, and in that the length of the footprint Lfp of the tire (4) on the ground is deduced from the distance between these two edges.

6. Method according to claim 1, characterized in that, for the determination of the period of rotation,

at least three successive measurements of the radial acceleration are made,

the measured values are compared in order to discard any measured value which is smaller than the other measured values by at least a predetermined threshold value,

the mean value of the validated measured values is calculated, and the value T of the period of revolution of the wheel (2) is determined using this mean value.

7. Method according to claim 6, characterized in that the value T of the period of revolution of the wheel (2) is determined on the basis of values of radial acceleration measured at time intervals which are at least substantially equal to 30 milliseconds.

8. Method according to claim 2, characterized in that the measurements of radial acceleration are made with a sampling period T/x equal to T/20.

9. Method according to claim 2, characterized in that the frame of reference defined by the origin sector So and the unit sector Su is used for the determination of the angular positions of the electronic module (5) in which the transmission of signals between said electronic module and a central unit (14) on board the vehicle (1) is commanded.

10. Method according to claim 2, characterized in that the frame of reference defined by the origin sector So and the unit sector Su is used for the determination of the angular positions of the electronic module (5) in which the transmission of signals between said electronic module and a central unit (14) on board the vehicle (1) is commanded.

11. Method according to claim 3, characterized in that the frame of reference defined by the origin sector So and the unit sector Su is used for the determination of the angular positions of the electronic module (5) in which the transmission of signals between said electronic module and a central unit (14) on board the vehicle (1) is commanded.

12. Method according to claim 2, characterized in that a series of measurements are made in the origin sector So, after at least one revolution of the wheel (2) following the detection of said origin sector, with a sampling frequency adapted to allow the subsequent detection of a variation in radial acceleration corresponding to a falling edge followed by a variation in radial acceleration corresponding to a rising edge, and in that the length of the footprint Lfp of the tire (4) on the ground is deduced from the distance between these two edges.

13. Method according to claim 3, characterized in that a series of measurements are made in the origin sector So, after at least one revolution of the wheel (2) following the detection of said origin sector, with a sampling frequency adapted to allow the subsequent detection of a variation in radial acceleration corresponding to a falling edge followed by a variation in radial acceleration corresponding to a rising edge, and in that the length of the footprint Lfp of the tire (4) on the ground is deduced from the distance between these two edges.

14. Method according to claim 2, characterized in that, for the determination of the period of rotation,

at least three successive measurements of the radial acceleration are made,

the measured values are compared in order to discard any measured value which is smaller than the other measured values by at least a predetermined threshold value,

the mean value of the validated measured values is calculated, and the value T of the period of revolution of the wheel (2) is determined using this mean value.

15. Method according to claim 3, characterized in that, for the determination of the period of rotation,

at least three successive measurements of the radial acceleration are made,

the measured values are compared in order to discard any measured value which is smaller than the other measured values by at least a predetermined threshold value,

the mean value of the validated measured values is calculated, and the value T of the period of revolution of the wheel (2) is determined using this mean value.

16. Method according to claim 4, characterized in that, for the determination of the period of rotation,

at least three successive measurements of the radial acceleration are made,

the measured values are compared in order to discard any measured value which is smaller than the other measured values by at least a predetermined threshold value,

the mean value of the validated measured values is calculated, and the value T of the period of revolution of the wheel (2) is determined using this mean value.

17. Method according to claim 5, characterized in that, for the determination of the period of rotation,

at least three successive measurements of the radial acceleration are made,

the measured values are compared in order to discard any measured value which is smaller than the other measured values by at least a predetermined threshold value,

the mean value of the validated measured values is calculated, and the value T of the period of revolution of the wheel (2) is determined using this mean value.