Method for determining the position of a moving part along an axis, using an inductive sensor

Patent metadata

Field	Value
Publication number	US-2016349084-A1
Application number	US-201615165101-A
Country	US
Kind code	A1
Filing date	May 26, 2016
Priority date	May 27, 2015
Publication date	Dec 1, 2016
Grant date	—

Abstract

A method for determining the position θ of a moving part (T) along an axis (X), using an inductive sensor ( 10 ) including: a primary winding (B 1 ) generating an electromagnetic field; a first secondary winding (R 1 ), generating a first voltage signal (V 1 ), of the sine function type; a second secondary winding (R 2 ), generating a second voltage signal (V 2 ) of the cosine function type; and a calculation unit ( 20 ′), wherein the method includes the steps of calculating and distributing linearization points i on the arctangent function tan(θ) resulting from the ratio of the first voltage signal to the second voltage signal, the linearization points i being distributed according to a sinusoidal function in order to reduce the error on the position (θ) of the target (T) at the ends (E 1 , E 2 ) of the primary and secondary windings (R 1 , R 2 ).

First claim

1 . A method for determining the position of a moving part, called a “target” (T), along an axis (X), using an inductive sensor ( 10 ), said inductive sensor ( 10 ) comprising:
a primary winding (B 1 ) generating an electromagnetic field,
a first secondary winding (R 1 ), generating a first voltage signal (V 1 ) of the sine function type, representing the current induced in said first secondary winding (R 1 ) when the target (T) moves in front of the first secondary winding (R 1 ),
a second secondary winding (R 2 ), generating a second voltage signal (V 2 ) of the cosine function type, representing the current induced in said second secondary winding (R 2 ) when the target moves in front of the second secondary winding (R 2 ),
a calculation unit ( 20 ′),
said determination method including the following steps:
Step 1: calculating an arctangent function (tan(θe)) on the basis of the first voltage signal (V 1 ) and the second voltage signal (V 2 ),
Step 2: calculating an error (ε(θ)) between the arctangent function (tan(θ)) calculated in this way and a predetermined straight line (D L ),
Step 3: calculating the positions of linearization points (θ i ) of the arctangent function (tan(θ)) according to the formula

θ
i

=

(

i
-
1

)

×

C
u

(

n
-
1

)

-

[

sin


(

(

i
-
1

)

×
2
×
π

(

n
-
1

)

)

×
F
×

C
u

]

where:
i is the index of the linearization points, varying from 1 to n,
θ i is the position of the linearization point i as a spatial angle,
F is the spacing factor of the linearization points, where F>0 and F MAX is such that:

F
MAX

<

(

i
-
1

)

×

C
u

(

n
-
1

)

-

[

sin


(

(

i
-
1

)

×
2
×
π

(

n
-
1

)

)

×

C
u

]

C u is the useful travel of the sensor along the axis as a spatial angle.
Step 4: for each value of the arctangent function (tan(θ)), finding an index (i) of the linearization point such that:
θ i <θ<θ i+1

where:
θ i is the position of the linearization point i as a spatial angle,
θ i+1 is the position of the linearization point (i+1) as a spatial angle,
θ is a spatial angle.
Step 5: calculating a correction to be applied to the arctangent function (tan(θ)) according to the formula

Corr


(

tan


(
θ
)

)

=

ɛ


(

θ
i

)

+

[

ɛ


(

θ

i
+
1

)

-

ɛ


(

θ
i

)

Assignees

• Continental Automotive France
• Continental Automotive Gmbh

Inventors

• Gerardiere Olivier
• Blanc Jeremie
• Roux Jean-Louis

Classifications

• G01D5/2448

  Correction of gain, threshold, offset or phase control · CPC title

• G01D5/204 Primary

  by influencing the mutual induction between two or more coils (G01D5/22 takes precedence) · CPC title

• G01D5/22

  differentially influencing two coils · CPC title

• G01B7/02 Primary

  for measuring length, width or thickness (G01B7/004, G01B7/12 take precedence) · CPC title