Angle sensor and angle sensor system

Patent metadata

Field	Value
Publication number	US-11313666-B2
Application number	US-202017000484-A
Country	US
Kind code	B2
Filing date	Aug 24, 2020
Priority date	Aug 30, 2019
Publication date	Apr 26, 2022
Grant date	Apr 26, 2022

Abstract

An angle sensor includes a first magnetic sensor that outputs a first signal, a second magnetic sensor that outputs a second signal, and a processor that performs processing for generating an angle detection value. The processing for generating the angle detection value includes first processing for determining a first candidate value of the angle detection value, second processing for performing processing for determining an (n+1)th candidate value either once or more than once while incrementing n in value by one each time, the (n+1)th candidate value being determined by performing second computing processing using the first and second signals, first and second strengths, and an nth candidate value of the angle detection value, where n is an integer of 1 or more, and third processing for assuming the candidate value last determined by the second processing as the angle detection value.

First claim

What is claimed is:

1. An angle sensor configured to generate an angle detection value having a correspondence with an angle to be detected, the angle sensor comprising:
a first magnetic sensor that detects a first composite magnetic field at a first detection position, and outputs at least one first signal having a correspondence with an angle that a direction of the first composite magnetic field forms with respect to a reference direction, the first composite magnetic field being a composite magnetic field of a magnetic field to be detected and a noise magnetic field other than the magnetic field to be detected;
a second magnetic sensor that detects a second composite magnetic field at a second detection position different from the first detection position, and outputs at least one second signal having a correspondence with an angle that a direction of the second composite magnetic field forms with respect to the reference direction, the second composite magnetic field being a composite magnetic field of the magnetic field to be detected and the noise magnetic field; and
a processor that obtains the at least one first signal and the at least one second signal, and performs processing for generating the angle detection value, wherein
at the first and second detection positions, a direction of the magnetic field to be detected changes with the angle to be detected,
the magnetic field to be detected has a first strength at the first detection position,
the magnetic field to be detected has a second strength different from the first strength at the second detection position, and
the processing for generating the angle detection value includes
first processing for determining a first candidate value of the angle detection value by performing first computing processing using the at least one first signal, the at least one second signal, and the first and second strengths,
second processing for performing processing for determining an (n+1)th candidate value either once or more than once while incrementing n in value by one each time until n reaches a predetermined value, the (n+1)th candidate value being determined by performing second computing processing using the at least one first signal, the at least one second signal, the first and second strengths, and an nth candidate value of the angle detection value, where n is an integer of 1 or more, and
third processing for determining, when the second processing ends upon determining a last candidate value when n reaches the predetermined value, the angle detection value to be the last candidate value determined by the second processing.

2. The angle sensor according to claim 1 , wherein:
the at least one first signal is a signal including information about a first initial angle detection value indicating the angle that the direction of the first composite magnetic field forms with respect to the reference direction; and
the at least one second signal is a signal including information about a second initial angle detection value indicating the angle that the direction of the second composite magnetic field forms with respect to the reference direction.

3. The angle sensor according to claim 2 , wherein the first computing processing is processing for calculating the first candidate value by substituting the first and second initial angle detection values and a ratio of the first strength to the second strength into a first function for determining the angle detection value.

4. The angle sensor according to claim 2 , wherein the second computing processing is processing for calculating the (n+1)th candidate value by substituting the first and second initial angle detection values, a ratio of the first strength to the second strength, and the nth candidate value into a second function for determining the angle detection value.

5. The angle sensor according to claim 4 , wherein the second function includes a coefficient expressed by an equation using the nth candidate value of the angle detection value and at least one parameter.

6. The angle sensor according to claim 5 , wherein the at least one parameter includes a first parameter representing a ratio of a strength of the noise magnetic field to the first strength, a second parameter representing a ratio of the strength of the noise magnetic field to the second strength, and a third parameter representing an angle that a direction of the noise magnetic field forms with respect to the reference direction.

7. The angle sensor according to claim 5 , wherein the processor determines the at least one parameter by using a plurality of pairs of the first and second initial angle detection values obtained when the direction of the magnetic field to be detected makes at least one rotation in a predetermined direction of rotation, and a plurality of the first candidate values corresponding to the plurality of pairs or a plurality of the angle detection values corresponding to the plurality of pairs.

8. The angle sensor according to claim 1 , wherein:
the at least one first signal includes two signals having a correspondence with a cosine and a sine of the angle that the direction of the first composite magnetic field forms with respect to the reference direction; and
the at least one second signal includes two signals having a correspondence with a cosine and a sine of the angle that the direction of the second composite magnetic field forms with respect to the reference direction.

9. An angle sensor system comprising:
the angle sensor according to claim 1 ; and
a magnetic field generation unit for generating the magnetic field to be detected,
wherein the first and second detection positions are at mutually different distances from the magnetic field generation unit.

10. The angle sensor system according to claim 9 , wherein the first and second of detection positions are mutually different positions on an imaginary straight line passing through the magnetic field generation unit.

Assignees

• Tdk Corp

Inventors

• Antoku Yosuke

Classifications

• G01D5/145

  influenced by the relative movement between the Hall device and magnetic fields (see G01R33/06) · CPC title

• G01D5/16

  by varying resistance · CPC title

• G01B7/30 Primary

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