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DE-102017116297-B4 - Angle sensor and angle sensor system

DE102017116297B4DE 102017116297 B4DE102017116297 B4DE 102017116297B4DE-102017116297-B4

Abstract

Angle sensor (1), comprising: a detection signal generation unit (2) for generating a plurality of detection signals, each of which corresponds to an angle to be detected; an angle detection unit (3) for generating a detection angle value based on the plurality of detection signals, wherein the detection angle value corresponds to the angle to be detected; and a condition monitoring device (4), characterized by the fact that The state determination device (4) comprises: a determination value generation unit (41) for generating a determination value to be used to determine whether the angle sensor (1) is in a predetermined state; and a determination unit (42) for determining whether the angle sensor (1) is in a predetermined state based on the determination value. the angle detection unit (3) comprises a common correction processing unit (32) for carrying out common correction processing to convert a plurality of uncorrected signals corresponding to the plurality of detection signals into a plurality of jointly corrected signals to be used for generating the detection angle value and the determination value, the determination value generation unit (41) is configured to generate the determination value based on the plurality of jointly corrected signals, and the joint correction processing is a processing operation to convert the plurality of uncorrected signals into the plurality of jointly corrected signals, such that an angular error occurring in the detection angle value is reduced compared to the case where the detection angle value is generated using the plurality of uncorrected signals without the application of the joint correction processing, and such that a range over which the determination value varies depending on the angle to be detected is smaller than in the case where the determination value is generated using the plurality of uncorrected signals without the application of the joint correction processing. the angle detection unit (3) further comprises a non-common correction processing unit (33) for performing non-common Correction processing to convert the multitude of jointly corrected signals into a first angle operation signal and a second angle operation signal, which are used for an operation to generate the detection angle value and are not used for generating the determined value. The non-common correction processing is a processing to reduce an angular error that occurs in the acquisition angle value, compared to the case where the acquisition angle value is generated using the plurality of jointly corrected signals without the application of the non-common correction processing, and the non-common correction processing unit (33) is configured to convert the plurality of jointly corrected signals into the first and second angular operation signals, such that the range over which the determined value varies depending on the angle to be acquired, in the case where the determined value is generated using the first and second angular operation signals, is greater than or equal to the range over which the determined value varies, in the case where the determined value is generated using the plurality of jointly corrected signals.

Inventors

  • Kazuya Watanabe
  • Hiraku Hirabayashi

Assignees

  • TDK CORPORATION

Dates

Publication Date
20260513
Application Date
20170719
Priority Date
20160720

Claims (19)

  1. Angle sensor (1), comprising: a detection signal generation unit (2) for generating a plurality of detection signals, each of which corresponds to an angle to be detected; an angle detection unit (3) for generating a detection angle value based on the plurality of detection signals, wherein the detection angle value corresponds to the angle to be detected; and a state determination device (4), characterized in that the state determination device (4) comprises: a determination value generation unit (41) for generating a determination value to be used to determine whether the angle sensor (1) is in a predetermined state; and a determination unit (42) for determining whether the angle sensor (1) is in a predetermined state based on the determination value, the angle detection unit (3) comprising a common correction processing unit (32) for performing common correction processing to convert a plurality of uncorrected signals corresponding to the plurality of detection signals into a plurality of jointly corrected signals to be used for generating the detection angle value and the determination value, the determination value generation unit (41) is configured to generate the determination value based on the plurality of jointly corrected signals, and the common correction processing is a processing operation to convert the plurality of uncorrected signals into the plurality of jointly corrected signals, such that an angular error occurring in the detection angle value is reduced compared to the case where the detection angle value is generated using the plurality of uncorrected signals without the application of the common correction correction processing, and such that the range over which the determined value varies depending on the angle to be detected is smaller than in the case where the determined value is generated using the plurality of uncorrected signals without the application of joint correction processing, the angle detection unit (3) further comprises a non-joint correction processing unit (33) for performing non-joint correction processing to convert the plurality of jointly corrected signals into a first angle operation signal and a second angle operation signal, which are used for an operation to generate the detection angle value and are not used for generating the determined value, the non-joint correction processing being a processing to reduce an angular error that occurs in the detection angle value, compared to the case where the detection angle value is generated using the plurality of jointly corrected signals without the application of non-joint correction processing, and the non-joint correction processing unit (33) is configured to convert the plurality of jointly corrected signals into the first and second angle operation signals to convert so that the range over which the determined value varies depending on the angle to be measured, in the case where the determined value is generated using the first and second angle operation signals, is greater than or equal to the range over which the determined value varies, in the case where the determined value is generated using the multitude of jointly corrected signals.
  2. Angle sensor (1) according to Claim 1 , where the specified state is a state in which the angle sensor (1) has not failed.
  3. Angle sensor (1) according to Claim 1 or 2 , wherein the plurality of jointly corrected signals are a first jointly corrected signal and a second jointly corrected signal, where the angle to be detected varies with a predetermined period, the first and the second jointly corrected signal each contain an ideal component which varies periodically such that it follows an ideal sinusoidal curve, the ideal component of the first jointly corrected signal and the ideal component of the second jointly corrected signal have a phase difference of 90°, the first jointly corrected signal and the second jointly corrected signal have the same amplitude, and the determination value generation unit (41) is configured to generate the determination value by performing an operation comprising determining a sum of a square of the first jointly corrected signal and a square of the second jointly corrected signal.
  4. Angle sensor (1) according to one of the Claims 1 until 3 , wherein the angle to be detected is an angle formed by a direction of a rotating magnetic field at a reference position with respect to a reference direction, the detection signal generation unit (2) comprises a plurality of detection circuits (10, 20, 30) for generating the plurality of detection signals, and each of the plurality of detection circuits (10, 20, 30) comprises at least one magnetic detection element for detecting the rotating magnetic field.
  5. Angle sensor (1) according to Claim 4 , wherein the at least one magnetic sensing element comprises a plurality of series-connected magnetic resistance elements (50), and each of the plurality of magnetic resistance elements (50) comprises a pinned magnetic layer (53) whose magnetization direction is pinned, a free layer (51) whose magnetization direction varies depending on the direction of the rotating magnetic field, and a non-magnetic layer (52) located between the pinned magnetic layer (53) and the free layer (51).
  6. Angle sensor (1) according to one of the Claims 1 until 5 , wherein the joint correction processing includes processing to correct offsets of the multitude of uncorrected signals.
  7. Angle sensor (1) according to one of the Claims 1 until 6 , wherein the joint correction processing includes processing to normalize the amplitudes of the multitude of uncorrected signals.
  8. Angle sensor (1) according to one of the Claims 1 until 7 , wherein the plurality of uncorrected signals is a first uncorrected signal and a second uncorrected signal, the plurality of jointly corrected signals is a first jointly corrected signal and a second jointly corrected signal, where the angle to be detected varies with a predetermined period, the first uncorrected signal, the second uncorrected signal, the first jointly corrected signal, and the second jointly corrected signal each contain an ideal component that varies periodically such that it follows an ideal sinusoidal curve, and the joint correction processing includes processing to correct a phase difference between the ideal components of the first and second to set the jointly corrected signal to 90° regardless of any phase difference between the ideal components of the first and second uncorrected signal, and to ensure that the first and second jointly corrected signal have the same amplitude.
  9. Angle sensor (1) according to one of the Claims 1 until 8 , wherein if the angle to be detected varies with a predetermined period, each of the plurality of detection signals contains an ideal component which varies periodically such that it follows an ideal sinusoidal curve, and an error component which corresponds to a third harmonic of the ideal component, and the angle detection unit (3) further comprises a conversion processing unit (31) for performing conversion processing to convert the plurality of detection signals into the plurality of uncorrected signals, each of which contains a reduced error component compared to the error component contained in each of the plurality of detection signals.
  10. Angle sensor (1) according to one of the Claims 1 until 8 , wherein if the angle to be detected varies with a predetermined period, each of the plurality of uncorrected signals contains an ideal component that varies periodically such that it follows an ideal sinusoidal curve, and an error component corresponding to a third harmonic of the ideal component, and the joint correction processing comprises processing to bring about that each of the plurality of jointly corrected signals contains a reduced error component compared to the error component contained in each of the plurality of uncorrected signals.
  11. Angle sensor (1) according to one of the Claims 1 until 10 , wherein the angular error to be reduced by the non-common correction processing contains at least one consisting of a first angular error component and a second angular error component, and if the angle to be measured 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 1/2 the predetermined period.
  12. Angle sensor (1) according to Claim 11 , wherein the angular error to be reduced by the non-common correction processing includes the first angular error component, the non-common correction processing unit (33) is configured to convert the plurality of jointly corrected signals into the first and second angular operation signals, such that the first angular operation signal contains a first correction parameter, and the second angular operation signal contains a second correction parameter, wherein the first correction parameter is a parameter that causes an offset in the first angular operation signal, and wherein the second correction parameter is a parameter that causes an offset in the second angular operation signal.
  13. Angle sensor (1) according to Claim 11 , wherein the angular error to be reduced by the non-common correction processing includes the second angular error component, the non-common correction processing unit (33) is configured to convert the plurality of jointly corrected signals into the first and second angular operation signals, such that the first angular operation signal contains a third correction parameter, and the second angular operation signal contains a fourth correction parameter, the third correction parameter being a parameter that produces a phase difference between the first angular operation signal and the second angular operation signal of a value other than 90°, and the fourth correction parameter being a parameter that causes an amplitude of the first angular operation signal and an amplitude of the second angular operation signal to differ from each other.
  14. Angle sensor (1) according to one of the Claims 1 until 13 , wherein the angular error to be reduced by the non-common correction processing includes a third angular error component, and if the angle to be captured varies with a predetermined period, the third angular error component varies with a period of 1/4 of the predetermined period.
  15. Angle sensor system comprising: the angle sensor (1) according to Claim 1 ; and a physical information generation unit (5) for generating physical information corresponding to the angle to be detected, wherein the detection signal generation unit (2) is configured to generate the plurality of detection signals by detecting the physical information.
  16. Angle sensor system according to Claim 15 , where the physical information generation unit (5) is a magnetic field generation unit for generating a rotating magnetic field as physical information, and the angle to be detected is an angle formed by a direction of a rotating magnetic field at a reference position with respect to a reference direction.
  17. Angle sensor system according to Claim 15 or 16 , wherein a relative position of the physical information generation unit (5) with respect to the angle sensor (1) varies, so that the angle to be detected varies.
  18. Angle sensor system according to Claim 17 , wherein the relative position of the physical information generation unit (5) with respect to the angle sensor (1) varies such that it rotates about a central axis.
  19. Angle sensor system according to Claim 17 , wherein the relative position of the physical information generation unit (5) with respect to the angle sensor (1) varies linearly.

Description

BACKGROUND OF THE INVENTION 1. Technical field of the invention The present invention relates to an angle sensor and an angle sensor system, each comprising a state determination device. 2. Description of related technology In recent years, angle sensors have become widely used in various applications, such as detecting the rotational position of a steering wheel or a power steering motor in a motor vehicle. Angle sensors generate a detection angle value corresponding to a target angle. One example of an angle sensor is a magnetic angle sensor. An angle sensor system using a magnetic angle sensor typically includes a magnetic field generation unit to produce a rotating magnetic field whose direction changes in response to the rotation or linear motion of an object. The magnetic field generation unit could be, for example, a magnet. The angle to be detected by the magnetic angle sensor is, for example, the angle formed by the direction of the rotating magnetic field at a reference position relative to a reference direction. Known angle sensors include an angle sensor that comprises a detection signal generation unit for generating a multitude of detection signals of different phases and produces a detection angle value by performing an operation using the multitude of detection signals. In a magnetic angle sensor, the detection signal generation unit comprises a multitude of magnetic detection elements. Each of the multitude of magnetic detection elements includes, for example, a spin-valve magnetoresistive (MR) element comprising a pinned magnetic layer whose magnetization direction is pinned, a free layer whose magnetization direction varies depending on the direction of the rotating magnetic field, and a non-magnetic layer located between the pinned magnetic layer and the free layer. In the event of an angle sensor failure, caused by a failure of the detection signal generation unit or other factors, errors exceeding a permissible range may occur in the measured angle value. Therefore, the angle sensor must be equipped with a function to detect such failures. The resulting error in the measured angle value is subsequently referred to as the angle error. JP 2012-021842A This describes a technology for detecting the failure of a rotation angle sensing device that measures rotation angle based on two phase signals with phases shifted by 90°. The technology detects the failure by monitoring the sum of the squares of the two phase signals. JP 2012-021842A It also describes a technology for detecting the failure of a rotation angle sensing device that detects a rotation angle based on three or more phase signals with uniformly shifted phases. The technology detects the failure by monitoring the sum of the three or more phase signals. EP 2873951 A1 This describes a technology for detecting the failure of a rotation angle sensing device that measures a rotation angle based on first and second sinusoidal signals with a phase difference other than 90° or 180°. The technology detects the failure based on the first and second sinusoidal signals and the phase difference between them. According to the respective in JP 2012-021842A and EP 2873951 A1 In the described technology, a determination value indicating whether the rotary angle sensing device has failed is generated by performing an operation using a multitude of sensing signals. If the determination value exceeds a predefined range, it is determined that the rotary angle sensing device has failed. If the rotary angle sensing device has not failed, the determination value ideally shows a constant value, independent of the angle being measured. In the event of a failure of the rotary angle sensing device, the determination value will differ from the ideal value. For the angle sensor, which uses such a reference value to determine whether the angle sensor has failed, there are cases in which an angle error occurs and the reference value differs from the ideal value, even if the angle sensor has not failed. This can occur, for example, if the mean value and/or the amplitude and/or the phase of at least one of the detection signals deviates from its desired value. For example, in the case of a magnetic angle sensor, ideally the multitude of detection signals each have a waveform of a sinusoidal curve (comprising a sine waveform). and a cosine waveform) when the direction of the rotating magnetic field changes at a constant angular velocity and the angle to be detected varies with a predetermined period. However, there are cases where the waveforms of the detection signals are distorted with respect to a sinusoidal curve. Examples of causes for distortion of the detection signal waveforms include magnetic anisotropy of the free layer in the MR element in the magnetization direction of the pinned magnetic layer of the MR element, or variations in the magnetization direction of the pinned magnetic layer of the MR element due to the effect of the rotating magnetic field