Method for determining a pivoting angle of a wheel unit mounted onto a snap-in inflation valve

• US 9,891,045 B2
• Filed: 12/19/2011
• Issued: 02/13/2018
• Est. Priority Date: 12/30/2010
• Status: Active Grant

• Current Assignee: Continental Automotive France (Continental AG), Continental Automotive GmbH (Continental AG)
• Original Assignee: Continental Automotive France (Continental AG), Continental Automotive GmbH (Continental AG)
• Inventors: Vassilieff, Youri
• Primary Examiner(s): Lee, Paul D
• Application Number:
  US13/976,626
• Publication Number:
  US 20130304416A1
• Time in Patent Office: 2,248 Days
• Field of Search: 702151
• CPC Class Codes: B60C 23/0481 System diagnostic, e.g. monitoring battery voltage, detecting hardware detachments or identifying wireless transmission failures
• CPC Class Codes: B60C 23/0488 Movement sensor, e.g. for sensing angular speed, acceleration or centripetal force
• CPC Class Codes: B60C 23/0494 Valve stem attachments positioned inside the tyre chamber
• CPC Class Codes: G01B 21/22 for measuring angles or tapers; for testing the alignment of axes

Abstract

A method for determining a pivoting angle (α) of a wheel unit (12) mounted onto a snap-in inflation valve (10) includes the following three phases:

• • observation of a curve representing the effect of gravity on the radial acceleration A_mes of a wheel of the vehicle on a sensing axis Y′ which is related to the wheel unit and is not parallel to the axis of rotation of the wheel, by spectrum analysis of the gravity curve at a sampling frequency F_s greater than an assumed rotation speed ω of the wheel,
  • deduction of the actual rotation speed ω of the wheel, and
  • determination of the pivoting angle α according to the formula

$\cos \alpha =\frac{\stackrel{\_}{A_{\mathrm{mes}}}}{{\omega }^2\times R},$

• •  where ω is the actual angular speed deduced from the observation of the curve, A_mes is a mean value of the corrected radial acceleration, and R is a standardized radius of the wheel.

Claims

1. A method for determining a pivoting angle (α

) of a wheel unit (12) mounted onto a snap-in inflation valve (10), said valve being placed on a wheel of a motor vehicle, said method including the following;

with an inner end (15) of the inflation valve (10) positioned on a rim opening of the wheel and with the wheel unit (12) fastened to a head (19) of the inflation valve (10) so that the wheel unit (12) is mounted fixed to the inflation valve (10) with respect to rotation, rotating the wheel so that a pivoting angle of a wheel unit occurs while the wheel is rotating,

wherein the wheel unit has a measurement axis (Y) for measuring acceleration that allows the wheel unit, in an initial, non-pivoting position, to directly measure a radial acceleration (Arad) of the wheel,

wherein during rotation of the wheel when the wheel unit pivots about the rotation axis (X) in a first direction (P), the measurement axis (Y) is displaced from the initial, measurement position by a pivoting angle α

to a new position corresponding to a sensing axis (Y′

), wherein when the wheel unit pivots about the rotation axis (X), the sensing axis (Y′

) is non-parallel to an axis of rotation of the wheel,

the wheel unit pivots from the measurement axis (Y) to the sensing axis (Y′

) that deviates from the measurement axis (Y) by the pivoting angle α and

measures a radial acceleration (A_mes) on the sensing axis (Y′

), wherein, the method further includes the following phases;

Phase 1;

with the wheel pivoted and in rotation, measuring the radial accelerations (Ames) on the sensing axis (Y′

),

observation of a gravity curve C representing the effect of gravity on the radial acceleration (A_mes) of a wheel of the vehicle on the sensing axis (Y′

), by performing spectrum analysis of the gravity curve at a sampling frequency F_s greater than an assumed rotation speed ω

₀ of the wheel,

Phase 2;

deduction of an actual rotation speed ω

of the wheel, where ω

is the actual angular speed deduced from the observation of the gravity curve, and

Phase 3;

determination of the pivoting angle α

according to the formula

2. The method as claimed in claim 1, wherein in the spectrum analysis the curve C is assumed to be sinusoidal, and the spectrum analysis includes an identification between a discrete sampling of the acceleration value and a sinusoidal expression of said curve, with changing of the sampling frequency to provide convergence towards the actual rotation speed ω

of the wheel.

3. The method for determining a pivoting angle as claimed in claim 2, further comprising the following steps:

1a) measuring a radial acceleration A_mes of the wheel at a predetermined sampling frequency

4. The method for determining a pivoting angle as claimed in claim 1, further comprising the following steps:

1a) measuring a radial acceleration A_mes of the wheel at a predetermined sampling frequency

5. The method as claimed in claim 4, wherein the sampling frequency F_s is changed iteratively by executing steps 1a) to 2b) in a loop until the frequency F_s is equal to the rotation speed calculated in step 2a) of the preceding cycle.

6. The method as claimed in claim 4, wherein step 1b) is executed with the aid of a bandpass filter.

7. The method as claimed in claim 6, characterized in that the bandpass filter is a Butterworth filter.

8. The method as claimed in claim 4, wherein, in step 3a), the mean value of the radial acceleration is determined by measuring the radial acceleration four times per wheel revolution during four to five consecutive wheel revolutions.

9. The method as claimed in claim 1, wherein the initial sampling frequency F_s is within the range from 3×

16 to 30×

16 Hz.

10. The method as claimed in claim 1, wherein the sampling frequency F_s is chosen in such a way that at least sixteen acceleration measurements are made in each period.

11. The method as claimed in claim 1, wherein the method is performed when the vehicle is moving at a steady speed between 50 and 130 km/h without any significant change in speed in the period when the measurement of the radial acceleration (Ames) on the sensing axis (Y′

), is being made.

12. The method as claimed in claim 1, wherein the pivoting angle α

is calculated when the wheel has previously been subjected to an acceleration of 200 g or more.

13. The method as claimed in claim 1, wherein the diameter R of the wheel is standardized to 40.64 cm (16 inches).

14. The method as claimed in claim 1, wherein the wheel unit is comprised of:

temperature and pressure sensors,

an accelerometer,

a microprocessor,

a memory,

a battery,

an RF (radio frequency) transmitter device, and

an LF (low frequency) receiver device, and

the accelerometer is used in measuring the radial acceleration (Ames) on the sensing axis (Y′

).