METHOD FOR DETERMINING A PIVOTING ANGLE OF A WHEEL UNIT MOUNTED ONTO A SNAP-IN INFLATION VALVE

• US 20130304416A1
• Filed: 12/19/2011
• Published: 11/14/2013
• 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 GmbH (Continental AG)
• Inventors: Vassilieff, Youri
• Granted Patent: US 9,891,045 B2
• Time in Patent Office: Days
• US Class Current: 702/151
• 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 phases;

Phase 1;

observation of a curve C 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,

Phase 2;

deduction of an actual rotation speed ω

of the wheel, and

Phase 3;

determination of the pivoting angle α

according to the formula

2. The method as claimed in claim 1, characterized in that the spectrum analysis is what is known as “

on the fly”

spectrum analysis of the curve C which is assumed to be sinusoidal, by identification between a discrete sampling of the acceleration value and a formal expression of said curve, with continuous adaptation of the sampling frequency.

3. The method for determining a pivoting angle as claimed in claim 1, characterized in that it includes the following steps:

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

4. The method as claimed in claim 3, characterized in that the sampling frequency F_s is determined iteratively by executing steps 1a) to 2b) in a loop until this frequency F_s is equal to the rotation speed calculated in step 2a) of the preceding cycle.

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

16 to 30×

16 Hz.

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

7. The method as claimed in claim 1, characterized in that step 1b) is executed with the aid of a bandpass filter.

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

9. The method as claimed in claim 1, characterized in that, 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.

10. The method as claimed in claim 1, characterized in that it is used if 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 is being made.

11. The method as claimed in claim 1, characterized in that the pivoting angle α

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

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

13. The method for determining a pivoting angle as claimed in claim 2, characterized in that it includes the following steps:

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