Angle sensor and angle sensor system

Patent metadata

Field	Value
Publication number	US-2018022386-A1
Application number	US-201715649793-A
Country	US
Kind code	A1
Filing date	Jul 14, 2017
Priority date	Jul 20, 2016
Publication date	Jan 25, 2018
Grant date	—

Abstract

An angle sensor includes a detection signal generation unit for generating detection signals, an angle detection unit for generating a detected angle value on the basis of the detection signals, and a condition determination apparatus. The condition determination apparatus includes a determination value generation unit for generating a determination value to be used for determining the condition of the angle sensor, and a determination unit for determining the condition of the angle sensor. The angle detection unit includes a common correction processing unit for performing common correction processing for converting uncorrected signals, which have correspondence with the detection signals, into common corrected signals to be used for the generation of the detected angle value and the generation of the determination value. The common correction processing reduces an angular error occurring in the detected angle value, and narrows the variation range of the determination value.

First claim

What is claimed is:

1 . An angle sensor comprising:
a detection signal generation unit for generating a plurality of detection signals each of which has a correspondence with an angle to be detected; an angle detection unit for generating a detected angle value on the basis of the plurality of detection signals, the detected angle value having a correspondence with the angle to be detected; and a condition determination apparatus, wherein the condition determination apparatus includes: a determination value generation unit for generating a determination value to be used for determining whether the angle sensor is in a predetermined condition; and a determination unit for determining whether the angle sensor is in the predetermined condition on the basis of the determination value, the angle detection unit includes a common correction processing unit for performing common correction processing for converting a plurality of uncorrected signals, which have correspondence with the plurality of detection signals, into a plurality of common corrected signals to be used for the generation of the detected angle value and the generation of the determination value, the determination value generation unit is configured to generate the determination value on the basis of the plurality of common corrected signals, and the common correction processing is processing for converting the plurality of uncorrected signals into the plurality of common corrected signals so that an angular error occurring in the detected angle value is reduced relative to the case where the detected angle value is generated using the plurality of uncorrected signals without the application of the common correction processing, and so that a range over which the determination value varies depending on the angle to be detected is narrower than in the case where the determination value is generated using the plurality of uncorrected signals without the application of the common correction processing.

2 . The angle sensor according to claim 1 , wherein the predetermined condition is a condition in which the angle sensor has not failed.

3 . The angle sensor according to claim 1 , wherein
the plurality of common corrected signals are a first common corrected signal and a second common corrected signal, when the angle to be detected varies with a predetermined period, each of the first and second common corrected signals contains an ideal component which varies periodically in such a manner as to trace an ideal sinusoidal curve, the ideal component of the first common corrected signal and the ideal component of the second common corrected signal have a phase difference of 90°, the first common corrected signal and the second common corrected signal are of the same amplitude, and the determination value generation unit is configured to generate the determination value by performing an operation including determining a sum of a square of the first common corrected signal and a square of the second common corrected signal.

4 . The angle sensor according to claim 1 , wherein
the angle to be detected is an angle that a direction of a rotating magnetic field in a reference position forms with respect to a reference direction, the detection signal generation unit includes a plurality of detection circuits for generating the plurality of detection signals, and each of the plurality of detection circuits includes at least one magnetic detection element for detecting the rotating magnetic field.

5 . The angle sensor according to claim 4 , wherein
the at least one magnetic detection element includes a plurality of magnetoresistance elements connected in series, and each of the plurality of magnetoresistance elements includes a magnetization pinned layer whose magnetization direction is pinned, a free layer whose magnetization direction varies depending on the direction of the rotating magnetic field, and a nonmagnetic layer located between the magnetization pinned layer and the free layer.

6 . The angle sensor according to claim 1 , wherein the common correction processing includes processing for correcting offsets of the plurality of uncorrected signals.

7 . The angle sensor according to claim 1 , wherein the common correction processing includes processing for normalizing the amplitudes of the plurality of uncorrected signals.

8 . The angle sensor according to claim 1 , wherein
the plurality of uncorrected signals are a first uncorrected signal and a second uncorrected signal, the plurality of common corrected signals are a first common corrected signal and a second common corrected signal, when the angle to be detected varies with a predetermined period, each of the first uncorrected signal, the second uncorrected signal, the first common corrected signal and the second common corrected signal contains an ideal component which varies periodically in such a manner as to trace an ideal sinusoidal curve, and the common correction processing includes processing for making a phase difference between the ideal components of the first and second common corrected signals be 90° irrespective of a phase difference between the ideal components of the first and second uncorrected signals, and making the first and second common corrected signals be of the same amplitude.

9 . The angle sensor according to claim 1 , wherein
when the angle to be detected varies with a predetermined period, each of the plurality of detection signals contains an ideal component which varies periodically in such a manner as to trace an ideal sinusoidal curve, and an error component corresponding to a third harmonic of the ideal component, and the angle detection unit further includes a conversion processing unit for performing conversion processing for converting the plurality of detection signals into the plurality of uncorrected signals each containing a reduced error component relative to the error component contained in each of the plurality of detection signals.

10 . The angle sensor according to claim 1 , wherein
when the angle to be detected varies with a predetermined period, each of the plurality of uncorrected signals contains an ideal component which varies periodically in such a manner as to trace an ideal sinusoidal curve, and an error component corresponding to a third harmonic of the ideal component, and the common correction processing includes processing for causing each of the plurality of common corrected signals to contain a reduced error component relative to the error component contained in each of the plurality of uncorrected signals.

11 . The angle sensor according to claim 1 , wherein
the angle detection unit further includes a non-common correction processing unit for performing non-common correction processing for converting the plurality of common corrected signals into a first angle operation signal and a second angle operation signal which are used for an operation for generating the detected angle value and not used for the generation of the determination value, and the non-common correction processing is processing for reducing an angular error occurring in the detected angle value relative to the case where the detected angle value is generated using the plurality of common corrected signals without the application of the non-common correction processing.

12 . The angle sensor according to claim 11 , wherein
the angular error to be reduced by the non-common correction processing contains at least one of a first angular error component and a second angular error component, and when the angle to be detected varies with a predetermined period, the first angular error component vari

Assignees

• Tdk Corp

Inventors

• Watanabe Kazuya
• Hirabayashi Hiraku

Classifications

• G01L5/221

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

• B62D5/049

  detecting sensor failures · CPC title

• G01B7/30

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

• B62D15/0245 Primary

  Means or methods for determination of the central position of the steering system, e.g. straight ahead position · CPC title

• G01D5/145

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