# US 2018/0022386 A1 · Angle sensor and angle sensor system

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- Number: US 2018/0022386 A1
- Document ID: US20180022386A1
- Status: Published application
- Kind: A1
- Application number: 15/649,793
- Filed: 2017-07-14
- Published: 2018-01-25
- Earliest claimed: 2016-07-20
- Assignees: TDK Corporation
- Applicants: TDK Corporation
- Inventors: Kazuya WATANABE; Hiraku HIRABAYASHI
- Web page: https://patentgrep.com/patent/US20180022386A1

## CPC

- B62D 15/0245: {Means or methods for determination of the central position of the steering system, e.g. straight ahead position}
- B62D 5/049: {detecting sensor failures}
- G01B 7/30: for measuring angles or tapers; for testing the alignment of axes
- G01D 5/145: {influenced by the relative movement between the Hall device and magnetic fields (see G01R33/06)}
- G01D 5/2448: {Correction of gain, threshold, offset or phase control}
- G01L 5/221: {to steering wheels, e.g. for power assisted steering}
- B62D: MOTOR VEHICLES; TRAILERS (steering, or guiding on a desired track, of agricultural machines or implements A01B69/00; wheels, castors, axles, increasing wheel adhesion B60B; vehicle tyres, tyre inflation or tyre changing B60C; connections between vehicles of a train or the like B60D; vehicles for use on rail and road, amphibious or convertible vehicles B60F; suspension arrangements B60G; heating, cooling, ventilating or other air treating devices B60H; windows, windscreens, non-fixed roofs, doors or similar devices, protective coverings for vehicles not in use B60J; propulsion plant arrangements, auxiliary drives, transmissions, controls, instrumentation or dashboards B60K; electric equipment or propulsion of electrically-propelled vehicles B60L; power supply for electrically-propelled vehicles B60M; passenger accommodation not otherwise provided for B60N; adaptations for load transportation or to carry special loads or objects B60P; arrangement of signalling or lighting devices, the mounting or supporting thereof or circuits therefor, for vehicles in general B60Q; vehicles, vehicle fittings or vehicle parts not otherwise provided for B60R; servicing, cleaning, repairing, supporting, lifting, or manoeuvring, not otherwise provided for, B60S; brake arrangements, brake control systems or parts thereof B60T; air-cushion vehicles B60V; motor-cycles, accessories therefor B62J, B62K; testing of vehicles G01M)
- G01B: MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
- G01D: MEASURING NOT SPECIALLY ADAPTED FOR A SPECIFIC VARIABLE; ARRANGEMENTS FOR MEASURING TWO OR MORE VARIABLES NOT COVERED IN A SINGLE OTHER SUBCLASS; TARIFF METERING APPARATUS; MEASURING OR TESTING NOT OTHERWISE PROVIDED FOR
- G01L: MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE (weighing G01G)

## 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.

## Claims

### Claim 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.

### Claim 2 (depends on 1)

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

### Claim 3 (depends on 1)

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.

### Claim 4 (depends on 1)

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.

### Claim 5 (depends on 4)

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.

### Claim 6 (depends on 1)

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

### Claim 7 (depends on 1)

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

### Claim 8 (depends on 1)

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.

### Claim 9 (depends on 1)

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.

### Claim 10 (depends on 1)

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.

### Claim 11 (depends on 1)

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.

### Claim 12 (depends on 11)

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 varies with a period equal to the predetermined period, and the second angular error component varies with a period of ½ the predetermined period.

### Claim 13 (depends on 11)

The angle sensor according to claim 11, wherein
the angular error to be reduced by the non-common correction processing contains a third angular error component, and
when the angle to be detected varies with a predetermined period, the third angular error component varies with a period of ¼ the predetermined period.

### Claim 14 (depends on 1)

An angle sensor system comprising:
the angle sensor according to claim 1; and
a physical information generation unit for generating physical information having a correspondence with the angle to be detected,
wherein the detection signal generation unit is configured to generate the plurality of detection signals by detecting the physical information.

### Claim 15 (depends on 14)

The angle sensor system according to claim 14, wherein
the physical information generation unit is a magnetic field generation unit for generating a rotating magnetic field as the physical information, and
the angle to be detected is an angle that a direction of the rotating magnetic field in a reference position forms with respect to a reference direction.

### Claim 16 (depends on 14)

The angle sensor system according to claim 14, wherein a relative position of the physical information generation unit with respect to the angle sensor varies so that the angle to be detected varies.

### Claim 17 (depends on 16)

The angle sensor system according to claim 16, wherein the relative position of the physical information generation unit with respect to the angle sensor varies in such a way as to rotate about a central axis.

### Claim 18 (depends on 16)

The angle sensor system according to claim 16, wherein the relative position of the physical information generation unit with respect to the angle sensor varies in a linear fashion.