System and method for determining at least one parameter of at least one rotating member by means of an absolute position signal

• US 20050110625A1
• Filed: 11/12/2004
• Published: 05/26/2005
• Est. Priority Date: 11/21/2003
• Status: Active Grant

• Current Assignee: SNR Roulements
• Original Assignee: SNR Roulements
• Inventors: Duret, Christophe, Nicot, Christophe
• Granted Patent: US 7,283,925 B2
• Time in Patent Office: Days
• US Class Current: 340/445
• CPC Class Codes: B60C 23/0408 transmitting the signals by non-mechanical means from the wheel or tyre to a vehicle body mounted receiver

Abstract

The invention concerns a system for determining at least one parameter of at least one member (1) rotating with respect to a fixed structure (2), comprising, for each rotating member (1), an assembly comprising a transponder (3), a coder (5), an absolute position sensor (6) and a device (4) for detecting the parameter or parameters issuing from the transponder (3); the said system also comprising an activation device (7) which is connected to each sensor (6) and to each detection device (4), the said activation device being able, according to the absolute position of the coder, to activate the detection device (4) of an assembly when the transponder (3) of the assembly is in the transmission/reception cone of the communication means of the said detection device.

Claims

1. A system for determining at least one parameter of at least one member (1) rotating with respect to a fixed structure (2), said system comprising, for each rotating member (1), an assembly comprising:

a transponder (3) rotationally fixed to the rotating member (1), the transponder being able to measure the parameter or parameters to be determined;

a coder (5) rotationally fixed to the rotating member (1), the coder comprising a main track and a rotation pulse track, the rotation pulse track comprising a reference singularity whose angular position is indexed with respect to the angular position of the transponder (3) on the rotating member (1);

a sensor (6) fixed to the fixed structure (2), the sensor being disposed opposite to and at a reading distance from the coder (5), the sensor comprising an electronic circuit able to deliver a signal representing the angular position of the coder (5) with respect to the fixed structure (2) and a rotation pulse signal comprising a reference pulse corresponding to the detection of the reference singularity, the circuit also comprising means or resetting the coder position signal with respect to the position of the singularity so as to deliver an absolute position signal of the said coder (5) with respect to the singularity;

a device (4) for detecting the parameter or parameters issuing from the transponder (3), the device being fixed to the fixed structure (2) and comprising a communication means for sending an excitation signal to the transponder (3) and for receiving the measurement or measurements; and

an activation device (7) which is connected to each sensor (6) and to each detection device (4), the activation device being able, according to the absolute position of the coder, to activate the detection device (4) of an assembly when the transponder (3) of the assembly is in the transmission/reception cone of the communication means of the detection device.

2. A system according to claim 1, characterised in that the coder (5) is formed from a magnetic ring comprising on its surface the main track and the rotation pulse track which are concentric, the tracks comprising a succession of s North and South poles, the reference singularity being produced by a magnetic transition which is different from the others.

3. A system according to claim 1, characterised in that the reference singularity is indexed with respect to all the possible angular positions of the to transponder (3) on the rotating member (1), the activation device (7) being able to activate the detection device (4) when each possible angular position of the transponder (3) is in the transmission/reception cone of the communication means.

4. A system according to any one of claims 1 to 3, characterised in that each coder (5) also comprises means or coding the pulse which are different from one coder (5) to another, the activation device (7) comprising means or identifying the coding so as to activate the detection device (4) of the assembly of the coder (5) from which the pulse came.

5. A system according to claim 4, characterised in that the coding means comprise a number of supplementary singularities which are distributed over the coder (5).

6. A method of determining at least one parameter of at least one member (1) rotating with respect to a fixed structure (2) by a system according to claim 1, in which the activation device (7) compares the absolute position of the coder (5) with an activation position and, when the two positions are equal, the device activates or enables the activation of the detection device (4).

7. A method according to claim 6, characterised in that the activation position is equal, at least initially, to the indexed position of the transponder (3) with respect to the reference singularity.

8. A method according to claim 6, characterised in that it comprises an iterative procedure of optimising the activation position in which the quality of the signal issuing from the detection device (4) is analysed, and, if the quality is below a first threshold, the activation position is incremented and/or s decremented by a given step in order to determine a new optimised position which is used subsequently by the activation device (7) as the new activation position.

9. A method according to any one of claims 6 to 8, characterised in that, when to the activation device (7) enables activation, the latter is effected at variable interrogation periods which are determined as a function of operating conditions of the rotating member (1).

10. A method according to any one of claims 6 to 8, characterised in that the is indexed position of the transponder (3) with respect to the reference singularity is previously stored in the activation device (7).

11. A method according to any one of claims 6 to 8, characterised in that it comprises a prior procedure of indexing the position of the reference singularity with respect to the angular position of the transponder (3) on the rotating member (1).

12. A method according to claim 11, characterised in that the indexing procedure is effected by activation of the detection device (4) at fixed frequency and, when the signal measured by the said device is satisfactory, determination of the indexed position which is equal to the absolute position of the coder (5).

13. A method according to claim 8, characterized in that it comprises a prior procedure of indexing the position of the reference singularity with respect to the angular position of the transponder (3) on the rotating member (1), in which, if the quality of the signal is below a second threshold which is lower than the first threshold, the indexing procedure is carried out in place of the optimisation procedure.

14. A motor vehicle comprising a system according to any one of claims 1 to 3, each assembly being disposed so as to determine at least one parameter of a tyre (1) of the vehicle.

15. A vehicle according to claim 14, characterised in that the communication means is housed in the arch of the wheel on which the tyre (1) is mounted and in that the transponder (3) is housed in the valve of the tyre (1).

16. A method according to claim 13, characterised in that the indexing procedure is effected by activation of the detection device (4) at fixed frequency and, when the signal measured by the said device is satisfactory, determination of the indexed position which is equal to the absolute position of the coder (5).

17. A motor vehicle comprising a system according to claim 4, each assembly being disposed so as to determine at least one parameter of a tyre (1) of the vehicle.

18. A vehicle according to claim 17, characterised in that the communication means is housed in the arch of the wheel on which the tyre (1) is mounted and in that the transponder (3) is housed in the valve of the tyre (1).

19. A motor vehicle comprising a system according to claim 5, each assembly being disposed so as to determine at least one parameter of a tyre (1) of the vehicle.

20. A vehicle according to claim 19, characterised in that the communication means is housed in the arch of the wheel on which the tyre (1) is mounted and in that the transponder (3) is housed in the valve of the tyre (1).