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

Patent metadata

Field	Value
Publication number	US-9891045-B2
Application number	US-201113976626-A
Country	US
Kind code	B2
Filing date	Dec 19, 2011
Priority date	Dec 30, 2010
Publication date	Feb 13, 2018
Grant date	Feb 13, 2018

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
⁢

⁢
α

=

A
mes

_

ω

2
⁢

×
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.

First claim

The invention claimed is:

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

cos
⁢

⁢
α

=

A
mes

_

ω
2

×
R

,

 where A mes is a mean value of the measured radial accelerations, and R is a standardized radius of the wheel.

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

F
s

=

16
×

ω
0

2
×
π

,

where ω 0 is the assumed rotation speed of the wheel,
1b) filtering and determining a first sinusoidal curve C representing the variations of the radial acceleration sampled in step 1a), as a function of the rotation of the wheel, by eliminating noise and centering this curve on the origin,
1c) determining a surface area S 1 of this first sinusoidal curve C and a surface area S 2 of a second sinusoidal curve representing the integral of the first sinusoidal curve,
2a) determining a rotation speed ω 1 of the wheel by finding the ratio of these two surface areas according to the formula

S
1

S
2

=

ω
1

,

2b) verifying that the determined rotation speed ω 1 does match the sampling frequency F s of step 1a), and:
3a) when the determined rotation speed ω 1 is verified to match the sampling frequency F s of step 1a), determining the pivoting angle α after determination of a mean value of the radial acceleration A mes according to the relation:

cos
⁢

⁢
α

=

A
mes

_

ω
1
2

×
R

where
A mes is the mean value of the radial acceleration, ω 1 is the actual rotation speed of the wheel determined in step 2a, and R is a standardized radius of the wheel, and
3b) if this is not the case, repeating steps 1a) to 2b).

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

F
s

=

16
×

ω
0

2
×
π

,

where ω 0 is the assumed rotation speed of the wheel,
1b) filtering and determining a first sinusoidal curve C representing the variations of the radial acceleration sampled in step 1a), as a function of the rotation of the wheel, by eliminating noise and centering this curve on the origin,
1c) determining a surface area S 1 of this first sinusoidal curve C and a surface area S 2 of a second sinusoidal curve representing the integral of the first sinusoidal curve,
2a) determining a rotation speed ω 1 of the wheel by finding the ratio of these two surface areas according to the formul

Assignees

• Vassilieff Youri
• Continental Automotive France
• Continental Automotive Gmbh

Inventors

• Vassilieff Youri

Classifications

• B60C23/0481 Primary

  System diagnostic, e.g. monitoring battery voltage, detecting hardware detachments or identifying wireless transmission failures · CPC title

• G01B21/22 Primary

  for measuring angles or tapers; for testing the alignment of axes · CPC title

• B60C23/0494

  Valve stem attachments positioned inside the tyre chamber · CPC title

• B60C23/0488

  Movement sensor, e.g. for sensing angular speed, acceleration or centripetal force · CPC title