Inductive position sensor

Patent metadata

Field	Value
Publication number	US-11079291-B2
Application number	US-201815949762-A
Country	US
Kind code	B2
Filing date	Apr 10, 2018
Priority date	Apr 10, 2018
Publication date	Aug 3, 2021
Grant date	Aug 3, 2021

Abstract

Systems, devices, and methods for determining a torque on a target using an inductive torque sensor are described. The inductive torque sensor may include an excitation coil, two rotors, and two or more receive coils. Each of the receive coils and the rotors may be inductively coupled. The two or more receive coils may be configured to generate a received voltage which can be approximated by a sine waveform function based on the angular changes of the coils on each rotor, the distance of the receive coils from the rotors and the distance between the receive coils. An integrated circuit may be configured to determine the torque generated on the target based on calculated differences between the angular rotation of the first rotor versus the second rotor over a given period.

First claim

What is claimed is:

1. An inductive torque sensor, comprising:
a first rotor attached to a first member of a target;
a second rotor attached to a second member of the target;
a stator, aligned relative to the first rotor and the second rotor, comprising:
at least one magnetic field excitation element;
a first receiver comprising a first phased loop with a first geometry configured to output a first received signal (ST); and
a second receiver comprising a second phased loop with the first geometry configured to output a second received signal (SB);

a processor coupled to the stator and configured to:
receive the first received signal (ST) and the second received signal (SB); and
based on the received signals, determine a torque exerted on the target as a function of a delta angle ΔΘ.

2. The inductive torque sensor of claim 1 ,
wherein the target is an axle including the first member and the second member and a torsion bar separates and mechanically connects the first member with the second member.

3. The inductive torque sensor of claim 1 ,
wherein the delta angle (ΔΘ) is representative, at a given time, of a relative angular change between a change in rotational position of the first rotor (Θ RT ) versus a change in rotational position of the second rotor (Θ RB ).

4. The inductive torque sensor of claim 3 ,
wherein the first receiver is approximated as a first resulting average stator;
wherein the second receiver is approximated as a second resulting average stator;
wherein a known distance (D 0 ) exists between the first resulting average stator and the second resulting average stator;
wherein a first distance (D 1 ) arises between the first resulting average stator and the first rotor; and
wherein a second distance (D 2 ) arises between second resulting average stator and the second rotor.

5. The inductive torque sensor of claim 4 ,
wherein a known coupling attenuation (A 0 ) arises from the known distance (D 0 );
wherein a first coupling attenuation (A 1 ) arises from the first distance (D 1 );
wherein a second coupling attenuation (A 2 ) arises from the second distance (D 2 ); and
wherein each of the first received signal (ST) and the second received signal (SB) are a function of each of A 0 , A 1 , A 2 , Θ RT , and Θ RB .

6. The inductive torque sensor of claim 5 ,
wherein the first receiver and the second receiver comprise coils configured for use in at least one of a two-phase configuration and a three-phase configuration;
wherein the first received signal (ST) for a given phase (i) is defined pursuant to the equation:
STi=A 1 *sin(Θ RT +i *δ)− A 0 *A 2 *sin(Θ RB +i *δ)

wherein for a two-phase first receiver configuration,
i=0 or 1, and δ=90; and

wherein for a three-phase first receiver configuration,
i=0, 1 or 2, and δ=120.

7. The inductive torque sensor of claim 6 ,
wherein the second received signal (SB) for a given phase (i) of the second receiver is defined pursuant to the equation:
SBi=A 0* A 1 *sin(Θ RT +i *δ)− A 2 *sin(Θ RB +i *δ)

wherein for a two-phase second receiver configuration,
i=0 or 1, and δ=90; and

wherein for a three-phase second receiver configuration,
i=0, 1 or 2, and δ=120.

8. The inductive torque sensor of claim 7 ,
wherein each of the first receiver and the second receiver are configured in the two-phase configuration; and
wherein the processor is configured to determine the delta angle (ΔΘ) pursuant to the equation:

ΔΘ
=

tan

-
1

⁡

(

[

(

1
-

A
0

2

)

⁢
Z

]

A
0

⁡

(

W
+
X

)

-

(

1
+

A
0

2

)

⁢
Y

)

wherein:
W=the sum of square of the first received signal for each phase i;
X=the sum of square of the second received signal for each phase i;
Y=the sum, for each phase i, of the first received signal multiplied by the second received signal; and

for a low revolution per minute target:
Z=ST 0* SB 1− ST 1* SB 0

wherein:  ST0=the first received signal for an initial phase;  ST1=the first received signal for the first phase;  SB0=the second received signal for the initial phase; and  SB1=the second received signal for a first phase.

9. The inductive torque sensor of claim 7 ,
wherein each of the first receiver and the second receiver are configured in the three-phase configuration; and
wherein the processor is configured to determine the delta angle (ΔΘ) pursuant to the equation:

ΔΘ
=

tan

-
1

⁡

(

3

*

[

(

1
-

A
0

2

)

⁢
Z

]

Assignees

• Semiconductor Components Ind Llc

Inventors

• Bertin Jacques Jean

Classifications

• G01L3/105 Primary

  involving inductive means (G01L3/102, G01L3/104 take precedence) · CPC title

• G01D5/208

  using polyphase currents · CPC title

• G01L5/221

  to steering wheels, e.g. for power assisted steering · CPC title

• G01D5/2093

  using polyphase currents · CPC title