JP6535292B2 - Abnormality diagnosis device, abnormality diagnosis method, and program - Google Patents

Description

The present invention, an abnormality diagnosis apparatus, abnormality diagnosis method, and you and the program.

Conventionally, non-contact rotation angle sensors have been known which detect changes in the magnetic field in the X direction and Y direction and detect the rotation angle of a rotating magnet or the like based on the detection results (for example, Patent Documents 1 to 3 and Non Patent Document 1). Further, in order to prevent simultaneous failure of such rotation angle sensors, a redundant configuration has been known in which a plurality of different types of rotation angle sensors are provided.
Patent Document 1: Japanese Patent Application Publication No. 2011-106935 Patent Document 2: Japanese Patent Application Publication No. 2012-194193 Patent Document 3: US Patent No. 6,426,712 Non-Patent Document 1 RS Popovic, "Hall Effect Devices", Inst of Physics Pub Inc, May 1991

  Among such rotation angle sensors, a rotation angle sensor using a magnetoresistive element or the like has a small dynamic range, and the detection accuracy of the magnetic field may decrease depending on the magnetic field environment. In addition, a rotation angle sensor using a magnetoresistive element or the like can not detect a failure in which the magnetic field environment changes, such as dropping of a magnet. That is, the rotation angle sensor using the magnetoresistive element or the like had to separately measure whether or not it was an appropriate magnetic field environment. Therefore, in the redundant configuration including the rotation angle sensor using the magnetoresistive element or the like, the number of sensors increases and the control circuit or the like becomes complicated.

In a first aspect of the present invention, a first angle signal of a rotating body, which is output by a first signal detection device in accordance with a detection signal of a first rotation angle sensor that detects magnetic fields in different two directions, is obtained Second acquisition of a second angle signal and an amplitude signal of a rotating body output by a second signal detection device according to detection signals of a second rotation angle sensor that detects magnetic fields in at least two directions different from one acquisition unit And a first abnormality determination unit that determines abnormality of the first angle signal based on the amplitude signal, the first abnormality determination unit determining whether the amplitude signal is less than the first threshold or the amplitude signal is the first threshold Provided is an abnormality diagnosis apparatus, an abnormality diagnosis method, and a program for determining that the first angle signal is abnormal when larger than a second threshold larger than the second threshold .

  According to a second aspect of the present invention, there is provided a first rotation angle sensor for detecting magnetic fields in at least two different directions, and a first rotation angle sensor for outputting a first angle signal of a rotor according to a detection signal of the first rotation angle sensor. Second signal detection that outputs a second angle signal and an amplitude signal of a rotating body according to detection signals of a signal detection device, a second rotation angle sensor that detects different magnetic fields in at least two directions, and a second rotation angle sensor And the second rotation angle sensor provides an angle detection device having a larger dynamic range than the first rotation angle sensor.

  Note that the above summary of the invention does not enumerate all the necessary features of the present invention. In addition, a subcombination of these feature groups can also be an invention.

The structural example of the 1st rotation angle sensor 100 which concerns on this embodiment, and the 1st signal detection apparatus 200 is shown. The structural example of the magnetoresistive element 10 which concerns on this embodiment is shown. The structural example of the 1st rotation angle sensor 100 which concerns on this embodiment is shown. An example of an output signal to an external applied magnetic field of the 1st rotation angle sensor 100 concerning this embodiment is shown. The structural example of the rotation angle measurement system 20 which concerns on this embodiment is shown. An example of an operation flow of rotation angle measuring system 20 concerning this embodiment is shown. The modification of abnormality diagnosis device 1000 concerning this embodiment is shown. An example of an operation flow of rotation angle measurement system 20 in which abnormality diagnosis device 1000 of a modification concerning a present embodiment was provided is shown. The modification of rotation angle measuring system 20 concerning this embodiment is shown. The 1st modification of the 1st signal detection apparatus 200 which concerns on this embodiment, and the 2nd signal detection apparatus 400 is shown with the 1st rotation angle sensor 100 and the 1st signal detection apparatus 200. FIG. The 2nd modification of the 1st signal detection apparatus 200 concerning this embodiment and the 2nd signal detection apparatus 400 is shown with the 1st rotation angle sensor 100 and the 1st signal detection apparatus 200. As shown in FIG. An example of the hardware constitutions of the computer 1900 which functions as the abnormality diagnosis apparatus 1000 which concerns on this embodiment is shown.

  Hereinafter, the present invention will be described through the embodiments of the invention, but the following embodiments do not limit the invention according to the claims. Moreover, not all combinations of features described in the embodiments are essential to the solution of the invention.

  FIG. 1 shows a configuration example of a first rotation angle sensor 100 and a first signal detection device 200 according to the present embodiment. The first rotation angle sensor 100 detects, for example, the rotation angle of a rotating body rotating around a rotation axis in the vicinity of the sensor. The rotating body may be a rotating magnet, and the first rotation angle sensor 100 detects magnetic fields in at least two different directions of rotating magnetic fields formed by the rotating body. The first rotation angle sensor 100 detects, for example, a magnetic field in a first direction and a magnetic field in a second direction. The first rotation angle sensor 100 includes a first sensor 110 and a second sensor 120.

  For example, the first sensor 110 detects a magnetic field in a first direction, and the second sensor 120 detects a magnetic field in a second direction different from the first direction. In the present embodiment, a plane substantially perpendicular to the rotation axis of the rotating body is an XY plane, the first sensor 110 detects a magnetic field in the X direction, and the second sensor 120 detects the magnetic field in the Y direction substantially perpendicular to the X direction. An example of detecting a magnetic field will be described. The first sensor 110 and the second sensor 120 may be a magnetoresistive element (MR), a giant magnetoresistive element (GMR), a tunnel effect magnetoresistive element (TMR), an anisotropic magnetoresistive element (AMR) or the like. The first sensor 110 outputs the detection result Xch of the magnetic field in the X direction, and the second sensor 120 outputs the detection result Ych of the magnetic field in the Y direction as a detection signal of the first rotation angle sensor 100.

  The first signal detection device 200 outputs a first angle signal of the rotating body according to the detection signal of the first rotation angle sensor 100. The first signal detection device 200 outputs the rotation angle of the rotating magnet, for example, based on the detection result of the magnetic field in two directions. The first signal detection apparatus 200 includes an AD conversion unit 210, an AD conversion unit 212, and an angle detection unit 220.

  The AD conversion unit 210 and the AD conversion unit 212 convert the detection signal output from the first rotation angle sensor 100 into a digital signal. The first signal detection device 200 may be provided with a number corresponding to the number of detection signals output from the first rotation angle sensor 100 as the AD conversion unit. As one example, the AD conversion unit 210 receives a detection signal of the magnetic field in the X direction output by the first sensor 110, and converts the received detection signal into a digital signal. Also, as an example, the AD conversion unit 212 receives a detection signal of the magnetic field in the Y direction output by the second sensor 120, and converts the received detection signal into a digital signal. The AD conversion unit 210 and the AD conversion unit 212 may have a delta sigma type AD converter.

  The angle detection unit 220 calculates and outputs a first angle signal φ of the rotating body based on detection signals of magnetic fields in the X direction and the Y direction. Such first rotation angle sensor 100 and first signal detection device 200 can detect the rotation angle of the rotating body without contact. In addition, although the 1st rotation angle sensor 100 demonstrated the example provided with the 1st sensor 110 and the 2nd sensor 120, you may provide 3 or more sensors. The first sensor 110 and the second sensor 120 will be described next.

  FIG. 2 shows a configuration example of the magnetoresistive element 10 according to the present embodiment. The magnetoresistive element 10 is an example of a sensor element included in each of the first sensor 110 and the second sensor 120. The magnetoresistive element 10 may be TMR. The magnetoresistive element 10 has a pinned layer 12, an insulating layer 14 and a free layer 16.

  The pinned layer 12 is a ferromagnetic layer whose magnetization direction is fixed. FIG. 2 shows an example in which the pinned layer 12 is stacked in the Z-axis direction and magnetized in a predetermined direction in the XY plane. The magnetoresistive element 10 is arranged such that the magnetization direction of the pinned layer 12 is oriented in a predetermined direction.

  An insulating layer 14 is formed on the upper surface of the pinned layer 12. The insulating layer 14 is formed, for example, between the pinned layer 12 and the free layer 16 in the Z-axis direction, and electrically insulates the pinned layer 12 and the free layer 16. The insulating layer 14 may be formed to a thickness of about several nanometers.

  The free layer 16 is a ferromagnetic layer whose magnetization direction changes in accordance with an externally applied magnetic field. The free layer 16 is formed on the upper surface of the insulating layer 14, and the magnetization direction changes in a plane substantially parallel to the XY plane in which the pinned layer 12 is formed. The free layer 16 may change the magnetization direction by 360 degrees in the XY plane, following the direction of the external magnetic field.

  In such a magnetoresistive element 10, when a voltage is applied in the Z direction of the stacking direction, a current flows due to the tunnel effect. The electrical resistance of the magnetoresistive element 10 depends on the magnetization directions of the pinned layer 12 and the free layer 16. For example, when the magnetization directions of the pinned layer 12 and the free layer 16 are substantially the same, the electric resistance is low, and when the magnetization directions are opposite, the electric resistance is high. That is, in the magnetoresistive element 10, the electric resistance is lowest when the magnetization direction of the free layer 16 with respect to the pinned layer 12 is 0 °, and the electric resistance is highest when the magnetization direction is 180 °.

  Therefore, the resistance value of the magnetoresistive element 10 changes in accordance with the direction of the external magnetic field. The first sensor 110 and the second sensor 120 detect a rotating magnetic field using such a magnetoresistive element 10. An example of the first sensor 110 and the second sensor 120 using the magnetoresistive element 10 will now be described.

  FIG. 3 shows a configuration example of the first rotation angle sensor 100 according to the present embodiment. FIG. 3 shows an example of the first rotation angle sensor 100 formed on a substrate or the like, and a plane parallel to the substrate surface is taken as an XY plane. The first sensor 110 and the second sensor 120 are connected between the power supply unit and the reference potential, and respectively output a voltage according to the potential difference between the power supply unit and the reference potential. The first sensor 110 and the second sensor 120 may each have four magnetoresistive elements. The first sensor 110 includes a first magnetoresistive element 112, a second magnetoresistive element 114, a third magnetoresistive element 116, and a fourth magnetoresistive element 118.

  Each of the first magnetoresistive element 112, the second magnetoresistive element 114, the third magnetoresistive element 116, and the fourth magnetoresistive element 118 is an element that operates substantially the same as the magnetoresistive element 10 described in FIG. is there. Arrows shown in the elements of FIG. 3 indicate examples of the magnetization direction of the pinned layer 12 of each element. For example, the magnetization directions of the pinned layers 12 of the first magnetoresistance element 112 and the third magnetoresistance element 116 are respectively 180 ° (−X direction), and the magnetization directions of the second magnetoresistance element 114 and the fourth magnetoresistance element 118 The magnetization directions of the pinned layers 12 are the 0 ° direction (+ X direction), respectively.

  Here, for example, when a magnetic field B (θ = 0 °) in the + X direction is applied from the outside, the magnetization direction of each free layer 16 of the magnetoresistive element included in the first rotation angle sensor 100 is in the + X direction. . In this case, the magnetization directions of the free layer 16 with respect to the pinned layer 12 of the first magnetoresistance element 112 and the third magnetoresistance element 116 are respectively 180 °, and the respective electric resistances become the highest. In addition, the magnetization directions of the free layer 16 with respect to the pinned layer 12 of the second magnetoresistance element 114 and the fourth magnetoresistance element 118 are each 0 °, and the respective electric resistances become the lowest.

  Here, it is assumed that the first magnetoresistance element 112, the second magnetoresistance element 114, the third magnetoresistance element 116, and the fourth magnetoresistance element 118 change the range of substantially the same resistance value. When a rotating magnetic field B (θ) is applied from the outside, the change in the resistance value of the magnetoresistive element is represented by the inner product of the magnetization vector of the free layer 16 and the magnetization vector of the pinned layer 12.

When the magnetization vector of the free layer 16 follows the rotating magnetic field B (θ), for example, the magnitude of the magnetization vector of the free layer 16 with respect to the pinned layer 12 of the first magnetoresistance element 112 is expressed as A · cos (θ) Can. Further, since the magnetization vector of the pinned layer 12 is shifted by π with respect to the magnetization vector of the free layer 16 of the first magnetoresistance element 112, the change of the resistance value is A · cos (θ) · cos (π) It can be expressed as + R ₀ = −A · cos (θ) + R ₀ . That is, the resistance value of the first magnetoresistance element 112 changes between the minimum value −A + R ₀ (θ = 0) and the maximum value A + R ₀ (θ = π).

On the other hand, the change in the resistance value of the second magnetoresistance element 114 is A · cos (θ) · cos0 + R ₀ = A · cos (θ) + R ₀ . Also, the third magnetoresistive element 116 is substantially the same as the change in the resistance value of the first magnetoresistive element 112, and the fourth magnetoresistive element 118 is substantially the same as the change in the resistance value of the second magnetoresistive element 114. is there.

Since the potential difference V between the power supply unit and the reference potential is divided by two combinations of the first and second magnetoresistance elements 112 and 114 and the third and fourth magnetoresistance elements 116 and 118, respectively. The voltage V ₁ between the first magnetoresistance element 112 and the second magnetoresistance element 114 is V ₁ = V · (−A · cos (θ) + R ₀ ) / (2 · R ₀ ).

Similarly, the voltage V ₂ between the third magnetoresistance element 116 and the fourth magnetoresistance element 118 is V ₂ = V · (A · cos (θ) + R ₀ ) / (2 · R ₀ ). Therefore, the output voltage Xch of the first sensor 110 is Xch = V ₂ −V ₁ = V · A · cos (θ) / R ₀ . That is, the first sensor 110 outputs the output voltage Xch proportional to cos θ when the rotating magnetic field B (θ) is applied from the outside.

  The second sensor 120 includes a fifth magnetoresistive element 122, a sixth magnetoresistive element 124, a seventh magnetoresistive element 126, and an eighth magnetoresistive element 128. Each of the fifth magnetoresistive element 122, the sixth magnetoresistive element 124, the seventh magnetoresistive element 126, and the eighth magnetoresistive element 128 is an element that performs substantially the same operation as the magnetoresistive element 10 described in FIG. is there. The fifth magnetoresistive element 122, the sixth magnetoresistive element 124, the seventh magnetoresistive element 126, and the eighth magnetoresistive element 128 are the first magnetoresistive element 112, the second magnetoresistive element 114, and the third magnetoresistive element 116. , And the magnetization direction of the pinned layer 12 of the fourth magnetoresistive element 118 are each shifted by + 90 °.

Therefore, in the second sensor 120, when the rotating magnetic field B (θ) is applied from the outside, the difference between the magnetization direction of the pinned layer 12 of the fifth magnetoresistive element 122 and the direction of the rotating magnetic field B (θ = 0 °) Is 270 °, the change in the resistance value of the fifth magnetoresistance element 122 is −A · sin (θ) + R ₀ . Similarly, the change in the resistance value of the sixth magnetoresistance element 124 is A · sin (θ) + R ₀ . The seventh magnetoresistive element 126 is substantially the same as the change in resistance value of the fifth magnetoresistive element 122, and the eighth magnetoresistive element 128 is substantially the same as the change in resistance value of the sixth magnetoresistive element 124. is there.

The voltage V ₃ between the fifth magnetoresistive element 122 and the sixth magnetoresistive element 124 is V ₃ = V · (−A · sin (θ) + R ₀ ) / (2 · R ₀ ). Similarly, the voltage V ₄ between the seventh magnetoresistance element 126 and the eighth magnetoresistance element 128 is V ₄ = V · (A · sin (θ) + R ₀ ) / (2 · R ₀ ). Therefore, the output voltage Ych of the second sensor 120 is Ych = V ₄ −V ₃ = V · A · sin (θ) / R ₀ . That is, the second sensor 120 outputs the output voltage Ych proportional to sin θ when the rotating magnetic field B (θ) is applied from the outside.

Therefore, the angle detection unit 220 can calculate the first angle signal φ (θ) corresponding to the rotation angle θ of the rotating body according to the following equation using the above output voltages Xch and Ych.
(1)
φ (θ) = tan ⁻¹ (Ych / Xch)

  As described above, the first rotation angle sensor 100 and the first signal detection device 200 according to the present embodiment can calculate and output the first angle signal φ of the rotating body. However, in the magnetoresistive element included in the first rotation angle sensor 100, the dynamic range of the input magnetic field is small, and the detection accuracy of the magnetic field may decrease depending on the magnetic field environment.

  FIG. 4 shows an example of an output signal to an externally applied magnetic field of the magnetoresistive element according to the present embodiment. The horizontal axis of FIG. 4 indicates the magnitude of the applied magnetic field from the outside, and the vertical axis indicates the output signal output from the magnetoresistive element. FIG. 4 shows an example of input / output characteristics of magnetoresistance elements such as MR, GMR, TMR, and AMR by “xMR”.

  In the magnetoresistive element, when the external magnetic field is a relatively weak magnetic field, the direction of the magnetization of the free layer 16 does not follow the direction of the external magnetic field, and the detection accuracy may be degraded. When the external magnetic field is a relatively strong magnetic field, the magnetization direction of the free layer 16 follows the external magnetic field, but the magnetization direction of the pinned layer 12 also fluctuates following the external magnetic field, and the detection accuracy is degraded. Will occur. For example, although the magnetoresistive element can detect the magnetic field with high detection accuracy when the magnitude of the external magnetic field is in the range from the first threshold to the second threshold, the detection accuracy is degraded for the magnetic field outside the range Resulting in.

  Therefore, when measuring a magnetic field with a certain detection accuracy or more, the magnetoresistive element monitors whether or not the magnitude of the external magnetic field is within a predetermined range to determine whether the detection accuracy is degraded or not. Must. In addition, since the magnetoresistive element tends to saturate the characteristics of the output signal with respect to the external magnetic field, it is difficult to determine whether the detection accuracy has deteriorated based on the magnitude of the output signal of the magnetoresistive element. It is.

  In addition, the first rotation angle sensor 100 using the magnetoresistive element can not detect a failure in which the magnetic field environment changes, such as displacement, damage, or detachment of the magnet. Therefore, when the magnetic field is detected using the first rotation angle sensor 100, a device or the like separately monitoring the magnitude of the magnetic field applied to the magnetoresistive element is required. In particular, in the case of a redundant configuration in which a plurality of rotation angle sensors are provided for the purpose of improving reliability and ensuring safe operation, sensors etc. that detect an external magnetic field increase, and control circuits etc. become complicated.

  Therefore, the rotation angle measurement system according to the present embodiment has such a redundant configuration, acquires the magnitude of the external magnetic field without increasing the number of sensors for measuring the magnetic field environment, and the detected angle signal is normal. Diagnose whether or not. The rotation angle measurement system diagnoses whether or not the angle signal is normal by setting at least one of the plurality of types of rotation angle sensors as a rotation angle sensor using a Hall element. Such a rotation angle measurement system will be described next.

  FIG. 5 shows a configuration example of the rotation angle measurement system 20 according to the present embodiment. The rotation angle measurement system 20 includes a first rotation angle sensor 100, a first signal detection device 200, a second rotation angle sensor 300, a second signal detection device 400, and an abnormality diagnosis device 1000. The first rotation angle sensor 100 and the first signal detection device 200 have substantially the same operation as the operation of the rotation angle sensor using the magnetoresistive element described with reference to FIGS. 1 to 4, and thus the description thereof is omitted here. In addition, the first signal detection device 200 may be included in the abnormality diagnosis device 1000, and for example, the form in which the operation etc. processed in the first signal detection device 200 is processed in the abnormality diagnosis device 1000 is included. The same applies to the other examples according to the present embodiment.

  The second rotation angle sensor 300 detects magnetic fields in at least two different directions. The second rotation angle sensor 300 has a larger dynamic range of the input magnetic field than the first rotation angle sensor 100. Similar to the first rotation angle sensor 100, the second rotation angle sensor 300 detects the rotation angle of the rotating body that rotates around the rotation axis. The second rotation angle sensor 300 detects, for example, the magnetic field in the first direction and the magnetic field in the second direction. The second rotation angle sensor 300 may detect a magnetic field in a direction different from that of the first rotation angle sensor 100. The second rotation angle sensor 300 has a third sensor 310 and a fourth sensor 320.

  For example, the third sensor 310 detects a magnetic field in a first direction, and the fourth sensor 320 detects a magnetic field in a second direction different from the first direction. In the present embodiment, an example will be described in which the third sensor 310 detects a magnetic field in the X direction, and the fourth sensor 320 detects a magnetic field in the Y direction substantially perpendicular to the X direction. The third sensor 310 and the fourth sensor 320 may have Hall elements. The Hall element is, for example, an element that generates an electromotive force (Hall effect) in the Y-axis direction according to the magnetic field input in the Z-axis direction when current flows in the X-axis direction. The Hall element may be formed of a semiconductor or the like.

  An example in which the third sensor 310 and the fourth sensor 320 according to this embodiment each have a Hall element pair will be described. The third sensor 310 is, as an example, a pair of Hall elements arranged in the first direction. The fourth sensor 320 is, for example, a pair of Hall elements arranged in the second direction.

  The second rotation angle sensor 300 may have a magnetic focusing plate or the like that bends and converges the input magnetic field. The magnetic focusing plate is formed of a magnetic material or the like, and for example, the third sensor 310 having a magnetic field in the X-axis direction and / or the Y-axis direction bent to generate a component in the Z-axis direction and having sensitivity in the Z-axis direction. And the fourth sensor 320 respectively. The magnetic focusing plate may be formed on the upper surface of the substrate on which the second rotation angle sensor 300 is formed, or may be formed above the substrate via an insulating layer or the like.

  As an example, the magnetic focusing plate bends the magnetic field input in the + X direction, generates a magnetic field in the + Z direction in one Hall element of the third sensor 310, and generates a magnetic field in the -Z direction in the other Hall element, and inputs them. . Here, when the Hall element pair of the third sensor 310 is formed of substantially the same shape and substantially the same material, the magnetic sensitivities of the respective Hall elements are approximately equal. In addition, since the magnetic flux densities input to the respective Hall elements are opposite to each other, the generated Hall EMFs have different positive and negative signs.

  Therefore, by calculating the difference between the Hall EMF signals of the respective Hall elements, it is possible to output the magnetic field detection signal HallXch according to the magnetic field vector input in the X-axis direction. Further, since the magnetic field detection signal HallXch is the difference between the Hall electromotive forces of the Hall elements, the Hall elements are generated by the magnetic field having the same absolute value (in the + Z axis direction or the −Z axis direction) and the same absolute value. Hall electromotive force is offset and becomes almost zero.

  Similarly, the fourth sensor 320 arranges the second pair of Hall elements in the Y-axis direction, and calculates the magnetic field in the Y-axis direction by calculating the difference between the Hall EMF signals in the same manner as the third sensor 310. Can. That is, the second rotation angle sensor 300 can output the magnetic field detection signal HallYch according to the magnetic field vector input in the Y-axis direction using the fourth sensor 320. Therefore, the second rotation angle sensor 300 outputs the magnetic field detection signals HallXch and HallYch corresponding to the X axis component and the Y axis component of the input magnetic field vector.

Here, output signals from the third sensor 310 and the fourth sensor 320 are output according to the rotation angle θ of the rotating body. That is, as an example, the second rotation angle sensor 300 outputs a magnetic field detection signal represented by the following equation. Here, A is an amplitude value of each signal.
(2)
HallXch (θ) = A · cos (θ)
HallYch (θ) = A · sin (θ)

Therefore, the second angle signal ψ (θ) corresponding to the rotation angle θ of the rotating body can be calculated by the following equation, as an example.
(Number 3)
ψ (θ) = tan ⁻¹ {HallYch (θ) / HallXch (θ)}

  The two magnetic field detection signals of equation (2) are signals whose amplitude value, offset, and orthogonality are ideal, and are assumed to have no error. However, such an error may occur and the angle signal ψ (θ) may not coincide with the rotation angle θ. Therefore, the second signal detection device 400 performs closed loop processing so as to reduce the angular error signal ε (= ψ (θ) −θ), and detects the angle signal ψ (θ) of the second rotation angle sensor 300. Do.

  The second signal detection device 400 outputs the second angle signal and the amplitude signal of the rotating body in accordance with the detection signal of the second rotation angle sensor 300. The second signal detection device 400 may output an amplitude signal for determining an abnormality of the first angle signal φ output by the first signal detection device 200. The second signal detection apparatus 400 includes a first switching unit 410, a second switching unit 412, an amplification unit 420, an amplification unit 422, an AD conversion unit 430, an AD conversion unit 432, a first multiplication unit 440, a loop filter 450, and an angle update. The unit 460 includes a storage unit 470, a second multiplication unit 480, and an integration unit 490.

  The first switching unit 410 and the second switching unit 412 switch the direction of the current supplied to the Hall element of the second rotation angle sensor 300 based on the spinning current clock that repeats the first phase and the second phase, according to the magnetic field input. Invert the polarity of the signal component due to the signal component and the offset. Since the Hall element outputs an output signal including an offset signal specific to the element, the first switching unit 410 and the second switching unit 412 are described in Non-Patent Document 1 in order to reduce such an offset signal. The direction of the current flowing through the Hall element is switched using a spinning current method or the like.

For example, in the first phase, + the Z direction of the magnetic field input B, + first Hall element is energized in the X direction from the + Y direction side of the terminal generating holes electromotive force signal + V _S (in the -Y direction side with generating holes electromotive force signal -V _S) from the terminal, and outputs an offset voltage + _{V O} in the + Y direction. In this case, the first Hall element generates a hall electromotive force signal + V _S from the terminal on the + X direction side when the same magnetic field input in the + Z direction is energized in the −Y direction in the second phase (−X The Hall EMF signal -V _S is generated from the direction terminal, and the offset voltage + V _O in the + X direction is output. Therefore, to get the output voltage V _h11 from the Y-axis direction of the terminal of the Hall element in a first phase, by acquiring the output voltage V _h12 from the X-axis direction of the terminal of the Hall element in a second phase, the magnetic field of the Hall element The detection signal of B is expressed by the following equation.
(Number 4)
V _h11 = + 2 V _S + V _O
V _h12 = -2V _S + V _O

As described above, when the first switching unit 410 switches the conduction direction of the third sensor 310, the sign of the signal component of the Hall EMF signal V _S among the detection signals of the Hall element as shown in Equation 4. Can be inverted in the first phase and the second phase. That is, the spinning current method modulates the Hall electromotive force signal V _S with the spinning current clock to make it a modulation signal, and the offset voltage V _O is a DC signal output, so that two signals can be separated in the frequency domain Ideally, the offset signal can be removed using a filter or the like. Further, as in the case of the first switching unit 410, the second switching unit 412 may switch the conduction direction of the fourth sensor 320 to separate the Hall electromotive force signal and the offset voltage.

  The amplification unit 420 receives the modulation signal output from the first switching unit 410, and amplifies the modulation signal with a predetermined amplification factor. The amplification unit 420 supplies the amplified modulation signal to the AD conversion unit 430. The AD converter 430 converts the received modulated signal into a digital signal. The AD conversion unit 430 may include a delta sigma type AD converter. The AD conversion unit 430 may further include a demodulation unit that demodulates the converted digital signal using a spinning current clock and outputs a digital value Vx of the magnetic field detection signal HallXch. The demodulated digital value Vx is superimposed with a component obtained by modulating the DC offset, and therefore the demodulation unit may have a filter or the like to remove the modulated component of the DC offset.

  Similarly, the amplification unit 422 receives the modulation signal output from the second switching unit 412 and amplifies it with a predetermined amplification factor. The amplification unit 422 supplies the amplified modulation signal to the AD conversion unit 432. The AD converter 432 converts the received modulated signal into a digital signal. The AD conversion unit 432 may include a delta sigma type AD converter. The AD conversion unit 432 may further include a demodulation unit that demodulates the converted digital signal using a spinning current clock and outputs a digital value Vy of the magnetic field detection signal HallYch. The demodulated digital value Vy is superimposed with a component obtained by modulating a DC offset, so the demodulation unit may include a filter or the like to remove the modulated component of the DC offset.

The first multiplication unit 440 multiplies the digital signal Vx by the sine wave signal sin (ψ). The first multiplication unit 440 also multiplies the digital signal Vy by the cosine wave signal cos (cos). The sine wave signal sin (ψ) and the cosine wave signal cos (ψ) will be described later. The first multiplication unit 440 outputs the difference between the two multiplication results as an angular error signal ε, as shown by the following equation. Here, the amplification degree of the amplification unit 420 and the amplification unit 422 is 1.
(Number 5)
ε = −sin (ψ) · Vx + cos (ψ) · Vy

When the magnetic field detection signal is ideal, the angular error signal ε is expressed as follows.
(Number 6)
ε = −A · sin (ψ) · cos (θ) + A · cos (ψ) · sin (θ)
= A · sin (θ-ψ)
A A (θ-ψ)

  Here, since the second signal detection device 400 outputs the second angle signal ψ so as to follow the angle θ indicated by the magnetic field detection signal, the value of θ−ψ is given by sin (θ−ψ) ≒ (θ− The value is small enough to approximate to ψ). Therefore, the angular error signal ε calculated by the first multiplier 440 approximates to a value A · (θ−ψ) that is proportional to the phase difference of the second angle signal 角度 with respect to the angle θ, as shown by equation (6) it can. The first multiplication unit 440 supplies the calculated angular error signal ε to the loop filter 450.

  Loop filter 450 passes frequency components below the predetermined frequency in angular error signal ε. The loop filter 450 may be a low pass filter. The loop filter 450 may reduce quantization noise and the like generated by the AD conversion unit 430 and the AD conversion unit 432. Further, when the magnetic field detection signals HallXch and HallYch include components obtained by converting the DC offset signal into harmonic components by a spinning current method, the loop filter 450 may reduce the harmonic components. The loop filter 450 may be omitted if quantization noise and harmonic components included in the angular error signal ε can be ignored.

  The angle updating unit 460 increases or decreases the second angle signal 応 じ in accordance with the angle error signal ε that has passed through the loop filter 450. The angle updating unit 460 updates the second angle signal ψ so that the angle error signal ε approaches zero. The angle updating unit 460 may include, for example, two integrating units. In this case, the second signal detection device 400 is a type 2 servo circuit including two integrating units in the closed loop circuit. The angle updating unit 460 includes, as an example, two integrating units and a digitally controlled oscillator (DCO) circuit.

  When the angle error signal ε input to the angle update unit 460 is output as a bit stream by the AD conversion unit 430 and the AD conversion unit 432 as an example, the angle update unit 460 performs the first integration of the angle error signal ε The units may be integrated into a digital signal having a plurality of bits for each clock. Further, since the angular error signal ε is an angular difference such as A · (θ−ψ), the angular difference for each clock (that is, every unit time) is an angular velocity ω (rad / s) which is a time derivative of the angle. It will have a dimension.

  The angle updating unit 460 supplies the signal of the angular velocity ω to the DCO circuit to output a frequency signal corresponding to the angular velocity ω, and the second integration unit integrates the frequency signal to generate a second angle signal ψ. Generate The second integration unit may include an up-down counter that performs up-counting and down-counting operations, and integrates the current count value to the count value of the frequency signal up to the previous time to generate a second angle signal ψ. Do. That is, the angle updating unit 460 integrates the current phase difference (θ−ψ) with the previous second angle signal ψ, and calculates a second angle signal ψ closer to the current rotation angle θ.

  The storage unit 470 stores, in advance, sine wave signals sin (ψ) and cosine wave signals cos (ψ) corresponding to the plurality of second angle signals ψ. The storage unit 470 supplies the first multiplication unit 440 with the sine wave signal sin (ψ) and the cosine wave signal cos (ψ) corresponding to the received second angle signal ψ. That is, the storage unit 470 feeds back the corresponding sine wave signal sin (ψ) and cosine wave signal cos (ψ) to the first multiplication unit 440 according to the acquired second angle signal ψ.

  The second signal detection apparatus 400 of the present embodiment outputs the second angle signal ψ brought closer by θ by the feedback loop that has passed through the first multiplication unit 440, the loop filter 450, the angle update unit 460, and the storage unit 470. can do. In addition, the second signal detection device 400 outputs an amplitude signal A (ψ) of the angle error signal ε based on the second angle signal ψ.

  In this case, the AD conversion unit 430 supplies the digital signal Vx to the first multiplication unit 440 and also supplies the digital signal Vx to the second multiplication unit 480. Similarly, the AD conversion unit 432 supplies the digital signal Vy to the first multiplication unit 440 and also supplies the digital signal Vy to the second multiplication unit 480. Further, the storage unit 470 supplies the sine wave signal sin (ψ) and the cosine wave signal cos (ψ) corresponding to the second angle signal に to the second multiplication unit 480.

The second multiplication unit 480 multiplies the digital signal Vx by the cosine wave signal cos (ψ). Further, the second multiplication unit 480 multiplies the digital signal Vy by the sine wave signal sin (ψ). The second multiplication unit 480 outputs the sum of the two multiplication results as an amplitude signal A (ψ) via the integration unit 490, as shown by the following equation. Here, the amplification degree of the amplification unit 420 and the amplification unit 422 is 1.
(Number 7)
A (ψ) = cos (ψ) · Vx + sin (ψ) · Vy

When the magnetic field detection signal is an ideal signal and the second angle signal ψ has a value substantially equal to θ, the amplitude signal A (ψ) is expressed as follows.
(Number 6)
A (ψ) = [A ² · {cos (θ)} ² + A ² · {sin (θ)} ² ] ^1/2 = A

  As described above, by using the second rotation angle sensor 300 using the Hall element and the servo operation by the second signal detection device 400, the second angle signal ψ corresponding to the rotation angle θ of the rotating body and the amplitude signal of the magnetic field are It is possible to output with high accuracy. Thus, the rotation angle measurement system 20 has a redundant configuration including the first rotation angle sensor 100 and a second rotation angle sensor 300 of a type different from the first rotation angle sensor 100, and the second rotation Since the amplitude signal of the magnetic field input by the angle sensor 300 is detected, the abnormality of the first angle signal φ detected by the first rotation angle sensor 100 can be determined using the amplitude signal.

  The abnormality diagnosis device 1000 diagnoses an abnormality of the first angle signal φ output by the first rotation angle sensor 100 based on the second angle signal ψ and the amplitude signal output by the second signal detection device 400. In addition, the abnormality diagnosis device 1000 may diagnose an abnormality of the second angle signal ψ. The abnormality diagnosis apparatus 1000 includes a first acquisition unit 1010, a second acquisition unit 1020, and a first abnormality determination unit 1030.

  The first acquisition unit 1010 acquires the first angle signal φ of the rotating body output by the first signal detection device 200. The first acquisition unit 1010 may be connected to the first signal detection device 200 by wire, wireless, or a network, and may acquire the first angle signal φ. In addition, the first acquisition unit 1010 may be connected to a storage device or the like, and may acquire the output of the first signal detection apparatus 200 stored in the storage device or the like. The first acquisition unit 1010 supplies the acquired first angle signal φ to the first abnormality determination unit 1030.

  The second acquisition unit 1020 acquires the second angle signal ψ and the amplitude signal of the rotating body output from the second signal detection device 400. The second acquisition unit 1020 may be connected to the second signal detection device 400 by wire, wireless, or a network, and may acquire the second angle signal ψ. Also, the second acquisition unit 1020 may be connected to a storage device or the like, and may acquire the output of the second signal detection device 400 stored in the storage device or the like. The second acquisition unit 1020 supplies the acquired second angle signal ψ and the amplitude signal to the first abnormality determination unit 1030.

  The first abnormality determination unit 1030 determines the abnormality of the first angle signal φ based on the amplitude signal. For example, in the magnetoresistive element used by the first rotation angle sensor 100, as described in FIG. 4, the detection accuracy decreases when the magnitude of the external magnetic field is less than the first threshold or exceeds the second threshold. On the other hand, since the Hall element used by the second rotation angle sensor 300 is not a sensor based on the magnetization of the pinned layer, the free layer or the like, the accuracy deterioration due to the magnitude of the external magnetic field is unlikely to occur.

  As shown by “Hall” in FIG. 4 as an example of the input / output characteristics of the Hall element, the magnitude of the output signal with respect to the external magnetic field is substantially linear. Therefore, the Hall element can detect the magnetic field with high accuracy in a wide intensity range of the external magnetic field as compared with the magnetoresistive element. For example, the Hall element can detect the external magnetic field with high accuracy in the range from the 0th threshold to the 3rd threshold. As shown in FIG. 4, the zeroth threshold is smaller than the first threshold, and the third threshold is larger than the second threshold. As an example, the zeroth threshold is 10 mT, the first threshold is 20 mT, the second threshold is 40 mT, and the third threshold is 60 mT.

  Therefore, the first abnormality determination unit 1030 can determine, using the amplitude signal of the second rotation angle sensor 300, whether or not the detection accuracy of the first rotation angle sensor 100 is lowered. The first abnormality determination unit 1030 determines that at least the first angle signal φ is abnormal, for example, when the amplitude signal is smaller than the first threshold or the amplitude signal is larger than the second threshold larger than the first threshold. In the present embodiment, the nth threshold value of the amplitude signal is a threshold value corresponding to the nth threshold value of the external magnetic field shown in FIG. In addition, the first abnormality determination unit 1030 may determine whether to perform the abnormality determination of the angle signal based on the first angle signal φ and the second angle signal ψ.

  The rotation angle measurement system 20 according to the present embodiment as described above diagnoses whether or not the detected angle signal is normal without increasing the number of sensors that measure the magnetic field environment. The operation of such a rotation angle measurement system 20 will now be described.

  FIG. 6 shows an example of the operation flow of the rotation angle measurement system 20 according to the present embodiment. The rotation angle measurement system 20 executes the operation flow shown in FIG. 6 to detect whether the rotation angle of the rotating body is detected, and whether or not the accuracy of the detected first angle signal φ and second angle signal ψ is lowered. Determine In the present embodiment, the rotation angle measurement system 20 determines that the angle signal detected when the detection accuracy is lowered is “abnormal”, but instead, the rotation angle measurement system 20 “fails”. It may be determined that

  First, the rotation angle measurement system 20 detects the rotation angle of the rotating body (S710). As described in FIGS. 1 to 4, the first signal detection device 200 outputs the first angle signal φ of the rotating body in accordance with the detection signal of the first rotation angle sensor 100. Further, as described in FIG. 5, the second signal detection device 400 outputs the second angle signal ψ and the amplitude signal of the rotating body in accordance with the detection signal of the second rotation angle sensor 300. Then, the first acquisition unit 1010 acquires the first angle signal φ, and the second acquisition unit 1020 acquires the second angle signal ψ and the amplitude signal.

Next, the first abnormality determination unit 1030 determines whether the angle signal is normal based on the first angle signal φ and the second angle signal ψ (S720). If the absolute value | φ− 第 | of the difference between the first angle signal φ and the second angle signal 以下 is smaller than or equal to a predetermined angle signal threshold θ _th, the first abnormality determination unit 1030 determines the first angle signal φ and the first angle signal φ. It is determined that the second angle signal 正常 is normal and the abnormality determination is not performed (S720: Yes).

  In this case, the rotation angle measurement system 20 may output the first angle signal φ and / or the second angle signal 外部 to the outside as the measurement result of the rotation angle. Also, the rotation angle measurement system 20 may return to S710 and continue detection of the rotation angle. Further, the rotation angle measurement system 20 may end the detection of the rotation angle according to a predetermined number of times, time, instructions or the like.

In addition, when the absolute value | φ− は | of the difference between the first angle signal φ and the second angle signal 超_え exceeds the angle signal threshold θ _th , the first abnormality determination unit 1030 determines the first angle signal φ and the first angle signal φ At least one of the two angle signals 判断 is determined to be abnormal, and the determination of abnormality is executed (S720: No). That is, the first abnormality determination unit 1030 has a difference exceeding the angle signal threshold θ _th in the first angle signal φ and the second angle signal で あ る, which are detection results of substantially the same rotation angle with respect to the same rotating body. Therefore, it is determined that abnormality has occurred in at least one of the first angle signal φ and the second angle signal 、, and the abnormality determination is performed.

The first abnormality determination unit 1030 determines that the first angle signal φ or the second angle signal 異常 is abnormal when the amplitude signal satisfies the third condition which is equal to or more than the first threshold and equal to or less than the second threshold (S730: Yes). judge. That is, although the amplitude signal indicates that the detection accuracy of the first rotation angle sensor 100 is in a good range, the first abnormality determination unit 1030 outputs the first angle signal φ and the second angle signal ψ. Since a difference exceeding the angle signal threshold θ _th occurs, it is determined that the first angle signal φ or the second angle signal ψ is abnormal. In this case, the first abnormality determination unit 1030 may output an error signal indicating that the first angle signal φ or the second angle signal 異常 is abnormal (S750), and the detection of the rotation angle may be ended.

  When the amplitude signal does not satisfy the third condition (S730: No), the first abnormality determination unit 1030 determines whether the amplitude signal satisfies the following second condition (S740). The first abnormality determination unit 1030 determines that the first angle signal φ and the second angle signal 異常 are abnormal if the amplitude signal is less than the zeroth threshold or the second condition that the amplitude signal is larger than the third threshold is satisfied. (S740: Yes).

  That is, in response to the amplitude signal indicating that the first abnormality determination unit 1030 is a range in which the detection accuracy of the first rotation angle sensor 100 and the detection accuracy of the second rotation angle sensor 300 are both reduced, the first angle signal φ and It is determined that the second angle signal ψ is abnormal. In this case, the first abnormality determination unit 1030 may output an error signal indicating that the first angle signal φ and the second angle signal 異常 are abnormal (S750), and the detection of the rotation angle may be ended.

  If the amplitude signal does not satisfy the second condition (S740: No), that is, the first abnormality determination unit 1030 determines that the amplitude signal is equal to or greater than the zeroth threshold and less than the first threshold, or the amplitude signal is the second threshold If the first condition larger than the third threshold value is satisfied, the first angle signal φ is determined to be abnormal. That is, in response to the amplitude signal indicating that the first abnormality determination unit 1030 is in a range where the detection accuracy of the second rotation angle sensor 300 is good and the detection accuracy of the first rotation angle sensor 100 is lowered. It is determined that the first angle signal φ is abnormal.

  In this case, the first abnormality determination unit 1030 outputs an error signal indicating that the first angle signal φ is abnormal (S760). Further, the rotation angle measurement system 20 may output the second angle signal ψ based on the detection result of the second rotation angle sensor 300, which has good detection accuracy, to the outside as the measurement result of the rotation angle. The rotation angle measurement system 20 may return to S710 and continue detection of the rotation angle because the second rotation angle sensor 300 has good detection accuracy. Further, the rotation angle measurement system 20 may end the detection of the rotation angle according to a predetermined number of times, time, instructions or the like.

  As described above, the rotation angle measurement system 20 according to the present embodiment uses the second rotation angle sensor 300 using the Hall element to acquire the amplitude signal in addition to the angle signal of the rotating magnetic field, thereby to obtain the magnetoresistance. The detection accuracy of the first rotation angle sensor 100 using an element can be determined. The rotation angle measurement system 20 can also determine the detection accuracy of the second rotation angle sensor 300 using the amplitude signal. Therefore, the rotation angle measurement system 20 has a redundant configuration, and prevents a failure in changing the magnetic field environment such as a decrease in detection accuracy and a dropout of a magnet while preventing an increase in the number of sensors and an increase in complicated control circuits. It can be detected.

  The above-described rotation angle measurement system 20 according to the present embodiment has a redundant configuration having one first rotation angle sensor 100 using a magnetoresistive element and one second rotation angle sensor 300 using a Hall element. explained. Alternatively, the rotation angle measurement system 20 may further include a magnetoresistive element, a Hall element, and / or another measurement element or the like.

  FIG. 7 shows a modification of the abnormality diagnosis apparatus 1000 according to the present embodiment. The abnormality diagnosis apparatus 1000 of the present modification executes a more detailed abnormality determination. Further, the abnormality diagnosis apparatus 1000 of the present modification corrects the first angle signal φ in accordance with the abnormality determination of the first angle signal φ. The abnormality diagnosis apparatus 1000 of the present modification further includes a correlation signal calculation unit 1040, a second abnormality determination unit 1050, a correction unit 1060, a storage unit 1070, a third abnormality determination unit 1080, and an output unit 1090. Prepare.

  The correlation signal calculation unit 1040 calculates a correlation signal between a measured signal based on the amplitude signal and a predetermined periodic signal. The correlation signal calculation unit 1040 calculates an Nth power signal (N is a natural number of 1 or more) of the amplitude signal as a signal to be measured. For example, the correlation signal calculation unit 1040 sets the amplitude signal A (ψ) as a signal to be measured. Instead of this, the correlation signal calculation unit 1040 may use the square of the amplitude signal A (ψ) as the signal to be measured. Further, the correlation signal calculation unit 1040 Fourier-transforms the amplitude signal to calculate a correlation signal.

  The second abnormality determination unit 1050 determines the abnormality of the second angle signal 基 づ き based on the correlation signal. As an example, the second abnormality determination unit 1050 determines that the second angle signal 異常 is abnormal when the absolute value of the predetermined frequency component of the correlation signal exceeds the correlation signal threshold. The second abnormality determination unit 1050 determines that the second angle signal ψ is normal when the absolute value of the predetermined frequency component of the correlation signal is less than or equal to the correlation signal threshold.

  When the amplitude signal satisfies the first condition, the correction unit 1060 corrects the first angle signal φ output by the first signal detection device 200 based on the amplitude signal. The correction unit 1060 corrects the detection signal of the first rotation angle sensor 100 according to the magnitude of the amplitude signal because the detection accuracy of the amplitude signal output from the second signal detection device 400 is good. The correction unit 1060 may correct the detection signal using a correction value that is predetermined according to the magnitude of the amplitude signal.

  The storage unit 1070 corresponds to the magnitude of the amplitude signal, and stores the correction value that the correction unit 1060 uses for correction. The storage unit 1070 may store data and the like generated by the abnormality diagnosis device 1000. In addition, the storage unit 1070 may store intermediate data and the like to be processed in the process of generating the data and the like. Further, the storage unit 1070 may supply the stored data to the request source in response to a request from each unit in the abnormality diagnosis apparatus 1000.

The third abnormality determination unit 1080 determines that the absolute value of the difference between the first angle signal φ ′ corrected by the correction unit 1060 and the second angle signal す る output by the second signal detection device 400 exceeds the angle signal threshold θ _th . In this case, it is determined that the first angle signal φ is abnormal. The third abnormality determination unit 1080 determines that the first angle signal φ is normal if the absolute value of the difference between the corrected first angle signal φ ′ and the second angle signal 以下 is less than or equal to the angle signal threshold θ _th. Good.

  The output unit 1090 rotates the angle signal output from the other of the first angle signal φ and the second angle signal 応 じ in response to the determination that one of the first angle signal φ and the second angle signal 異常 is abnormal. Output as an angle signal of the body. The output unit 1090 may output the first angle signal φ and / or the second angle signal 応 じ in response to the determination that the first angle signal 角度 and the second angle signal 正常 are normal. The output unit 1090 issues an error signal in response to the first angle signal φ and the second angle signal 判定 being determined to be abnormal.

  FIG. 8 shows an example of the operation flow of the rotation angle measurement system 20 provided with the abnormality diagnosis device 1000 of the modification according to the present embodiment. The rotation angle measurement system 20 executes the operation flow shown in FIG. 8 to detect whether the rotation angle of the rotating body is detected, and whether or not the accuracy of the detected first angle signal φ and second angle signal ψ is lowered. Determine In the operation flow of FIG. 8, the same reference numerals are given to the same parts as the operation of the operation flow shown in FIG. 6 and the description will be omitted.

  First, the rotation angle measurement system 20 detects the rotation angle of the rotating body (S710). The first acquisition unit 1010 acquires a first angle signal φ, and the second acquisition unit 1020 acquires a second angle signal ψ and an amplitude signal A (ψ).

Next, when the absolute value | φ− は | of the difference between the first angle signal φ and the second angle signal 以下 is equal to or less than a predetermined angle signal threshold θ _th , the first abnormality determination unit 1030 determines the first angle The signal φ and the second angle signal 判断 are determined to be normal, and the abnormality determination is not performed (S720: Yes). In this case, the output unit 1090 may output the first angle signal φ and / or the second angle signal 外部 to the outside as a measurement result of the rotation angle. Also, the rotation angle measurement system 20 may return to S710 and continue detection of the rotation angle.

In addition, when the absolute value | φ− は | of the difference between the first angle signal φ and the second angle signal 超_え exceeds the angle signal threshold θ _th , the first abnormality determination unit 1030 determines the first angle signal φ and the first angle signal φ At least one of the two angle signals 判断 is determined to be abnormal, and the determination of abnormality is executed (S720: No). The first abnormality determination unit 1030 determines that the first angle signal φ or the second angle signal 異常 is abnormal when the amplitude signal satisfies the third condition which is equal to or more than the first threshold and equal to or less than the second threshold (S730: Yes). judge.

In this case, the correlation signal calculation unit 1040 calculates a correlation signal (S732). Here, when an abnormality occurs in the second angle signal に よ っ て also by the servo operation of the second signal detection device 400, the amplitude value, the offset, and / or the orthogonality of the two magnetic field detection signals of equation (2) An error is considered to be the cause. For example, consider the case where the offset error of the third sensor 310 causes an abnormality of the second angle signal ψ. In this case, digital values output from the AD conversion unit 430 and the AD conversion unit 432 can be expressed as the following equation. V _{os — x} indicates an offset error.
(Number 7)
V _X (ψ) = A · cos (ψ) + V _{os_x}
V _Y (ψ) = A · sin (ψ)

In this case, the amplitude signal A (ψ) is calculated as follows. Here, Cx indicates a constant.
(Equation 8)
A (ψ) = {V _X (ψ) ² + V _Y (ψ) ² } ^1/2
= {A ² + V _{os x} ² + 2 · A · V _{os x x} cos (ψ)} ^1/2
C Cx + V _{os_x} · cos (ψ)

Thus, the amplitude signal A (ψ) has a component that varies as a cosine function according to the rotation angle ψ. Similarly, consider the case where the offset error of the fourth sensor 320 is the cause. In this case, digital values output from the AD conversion unit 430 and the AD conversion unit 432 can be expressed as the following equation. V _{os — y} indicates an offset error.
(Number 9)
V _X (ψ) = A · cos (ψ)
V _Y (ψ) = A · sin (ψ) + V _{os_y}

In this case, the amplitude signal A (ψ) is calculated as follows. Here, Cy represents a constant.
(Number 10)
A (ψ) = {V _X (ψ) ² + V _Y (ψ) ² } ^1/2
= {A ² + V _{os_y} ² + 2 · A · V _{os_y} · sin (ψ)} ^1/2
Cy Cy + V _{os_y} · sin (ψ)

  Thus, the amplitude signal A (ψ) has a component that changes like a sine function according to the rotation angle ψ. That is, when the magnetic field detection signal includes an offset error to the extent that an abnormality occurs in the second angle signal ψ, the amplitude signal A (ψ) has a component that fluctuates like a sine function and / or a cosine function. That is, the amplitude signal A (ψ) has frequency components substantially the same as the frequency ψ / (2π).

Instead of this, the correlation signal calculation unit 1040 may use the square of the amplitude signal A (ψ) as the signal to be measured. In this case, for example, the square of the amplitude signal A (ψ) of the equation (8) and the equation (10) is calculated as the equation (11) and the equation (12). That is, the amplitude signal A (ψ) ² has a component that varies as a sine function and / or a cosine function.
(Equation 11)
A (ψ) ² = V _X (ψ) ² + V _Y (ψ) ²
= A ² + V _{os _ x} ² + 2 · A · V _{os _ x} · cos (ψ)
(12)
A (ψ) ² = V _X (ψ) ² + V _Y (ψ) ²
= A ² + V _{os_y} ² + 2 · A · V _{os_y} · sin (ψ)

Next, consider the case where the mismatch of the magnetic sensitivity of the third sensor 310 causes the abnormality of the second angle signal ψ. In this case, digital values output from the AD conversion unit 430 and the AD conversion unit 432 can be expressed as the following equation. Here, the amplitude values of the detection signals of the third sensor 310 and the fourth sensor 320 are A _x and A _y, and the average value of A _x and A _y is A _avg .
(Equation 13)
V _X (ψ) = {A _avg + (A _x −A _y ) / 2} · cos (ψ)
V _Y (ψ) = {A _avg + (A _x + A _y ) / 2} · sin (ψ)

In this case, the amplitude signal A (ψ) is calculated as follows.
(Equation 14)
A (ψ) = {V _X (ψ) ² + V _Y (ψ) ² } ^1/2
AA _avg + {(A _x −A _y ) / 2} · cos (2ψ)

  Thus, the amplitude signal A (ψ) has a component that varies like a double-angle cosine function according to the rotation angle ψ. That is, the amplitude signal A (ψ) has frequency components substantially the same as the frequency ψ / π.

Now consider the case where the third sensor 310 contains non-orthogonality error between the signal corresponding to the first axis and the signal corresponding to the second axis and causes an anomaly of the second angle signal ψ. . In this case, digital values output from the AD conversion unit 430 and the AD conversion unit 432 can be expressed as the following equation. Here, the non-orthogonality error of the third sensor 310 and the fourth sensor 320 is α.
(Equation 15)
Vx (ψ) = A · cos (θ)
Vy (ψ) = A · sin (θ + α)

In this case, the amplitude signal A (ψ) is calculated as follows.
(Equation 16)
A (ψ) = {Vx (ψ) ² + Vy (ψ) ² } ^1/2
= A · {cos ² (ψ) + sin ² (ψ + α)} ^1/2
A A · [1 + α · {sin (2 ψ)} / 2]

  Thus, the amplitude signal A (ψ) has a component that fluctuates like a double angle sine function according to the rotation angle ψ. That is, the amplitude signal A (ψ) has frequency components substantially the same as the frequency ψ / π.

As described above, when the magnetic field detection signal includes an error of the amplitude value, the offset, and / or the orthogonality and an abnormality occurs in the second angle signal 、, the amplitude signal A (ψ) has a frequency ψ / π or ψ / A frequency component of approximately the same frequency as 2π is generated. Therefore, the correlation signal calculation unit 1040 uses the amplitude signal A (ψ) as a signal to be measured, and outputs a signal obtained by Fourier transforming the signal to be measured as a correlation signal. Further, the correlation signal calculation unit 1040 may set the amplitude signal A (ψ) ² as a signal to be measured, and output a signal obtained by Fourier transforming the signal to be measured as a correlation signal. Thereby, the second abnormality determination unit 1050 can determine from the correlation signal the presence / absence of a frequency component having a frequency substantially the same as the frequency ψ / π or ψ / 2π.

  Next, the second abnormality determination unit 1050 determines the abnormality of the second angle signal 基 づ き based on the correlation signal (S734). Since the correlation signal calculation unit 1040 converts the signal to be measured into a signal in the frequency domain and sets it as a correlation signal, the second abnormality determination unit 1050 is based on the magnitude of the frequency component corresponding to the error of the second rotation angle sensor 300. , And the abnormality of the second angle signal ψ can be determined.

  For example, when the component of the frequency ψ / 2π exceeds a predetermined correlation signal threshold, the second abnormality determination unit 1050 determines that the offset error is large and the second angle signal 異常 is abnormal. In addition, for example, when the component of the frequency ψ / π exceeds a predetermined correlation signal threshold, the second abnormality determination unit 1050 has a large mismatch in magnetic sensitivity and / or a non-orthogonality error, and the second angle signal Determine that the hemorrhoids are abnormal. In addition, when the magnitude of the other frequency component of the correlation signal exceeds the correlation signal threshold, the second abnormality determination unit 1050 may determine that some abnormality has occurred, and also in this case, the second angle signal ψ. May be determined to be abnormal.

  Since the first abnormality determination unit 1030 determines that the amplitude signal satisfies the third condition and the first angle signal φ or the second angle signal 異常 is abnormal, the second abnormality determination unit 1050 determines that the second angle When the signal ψ is determined to be abnormal, it can be determined that the first angle signal ψ is normal. In addition, when there is no frequency component exceeding the correlation signal threshold in the correlation signal, the second abnormality determination unit 1050 may determine that the second angle signal ψ is normal and the first angle signal 異常 is abnormal.

  The output unit 1090 outputs the angle signal determined by the second abnormality determination unit 1050 as normal as the angle signal of the rotating body (S736). Further, the output unit 1090 may output the information of the angle signal determined as abnormal by the second abnormality determination unit 1050 to the outside as an error signal. The rotation angle measurement system 20 may return to S710 and continue detection of the rotation angle because one of the rotation angle sensors has good detection accuracy. Further, the rotation angle measurement system 20 may end the detection of the rotation angle according to a predetermined number of times, time, instructions or the like.

  When the amplitude signal does not satisfy the third condition (S730: No), the first abnormality determination unit 1030 determines whether the amplitude signal satisfies the following second condition (S740). The first abnormality determination unit 1030 determines that the first angle signal φ and the second angle signal 異常 are abnormal if the amplitude signal is less than the zeroth threshold or the second condition that the amplitude signal is larger than the third threshold is satisfied. (S740: Yes). In this case, the first abnormality determination unit 1030 may output an error signal indicating that the first angle signal φ and the second angle signal 異常 are abnormal (S750), and the detection of the rotation angle may be ended.

  If the amplitude signal does not satisfy the second condition (S740: No), that is, the first abnormality determination unit 1030 determines that the amplitude signal is equal to or greater than the zeroth threshold and less than the first threshold, or the amplitude signal is the second threshold If the first condition larger than the third threshold value is satisfied, the first angle signal φ is determined to be abnormal.

  Here, the correction unit 1060 corrects the first angle signal φ determined to be abnormal (S742). The correction unit 1060, for example, calculates the magnitude of the external magnetic field from the amplitude signal, and corrects the first angle signal φ based on the calculated correction value corresponding to the external magnetic field. As an example, when the first rotation angle sensor 100 is configured by TMR or GMR and the intensity of the external magnetic field is strong (when the amplitude signal is larger than the second threshold and smaller than the third threshold), the first sensor In the pinned layers 12 of the sensor 110 and the second sensor 120, the magnetization direction fluctuates following the external magnetic field, and the detection accuracy is degraded.

In this case, since the magnetization vector of the pinned layer 12 generates a component that fluctuates following the external magnetic field, the change in the resistance value of the magnetoresistive elements of the first magnetoresistive element 112 and the third magnetoresistive element 116 is It can be expressed by a formula. Note that θ is the application direction of the external magnetic field, and α and β are functions of the magnetic field.
(17)
A · cos (θ) · {(1−α (B)) · cos (π) + β (B) · cos (θ)
+ R ₀ '

Similarly, the change in the resistance value of the magnetoresistive elements of the second magnetoresistive element 114 and the fourth magnetoresistive element 118 can be expressed by the following equation.
(Number 18)
A · cos (θ) · {(1−α (B)) · cos (0) + β (B) · cos (θ)
+ R ₀ '

In this case, the digital value Vx of the magnetic field detection signal HallXch and the digital value Vy of the magnetic field detection signal HallYch can be approximated as in the following equation. That is, the terms of A2 'and B2' are superimposed as an error.
(Equation 19)
Vx ≒ A1 · cos (θ) + A2 · cos ³ (θ)
= A1 '· cos (θ) + A2' · cos (3θ)
Vy B B1 · sin (θ) + B2 · sin ³ (θ)
= B1 '· sin (θ) + B2' · sin (3θ)

Further, the first angle signal φ output from the first signal detection device 200 can be approximated as in the following equation. That is, the angular error (φ−θ) becomes C1 · sin (4θ).
(Equation 20)
φ = tan ⁻¹ (Vy / Vx)
Θ θ + C1 · sin (4θ)

  As described above, if the values of A2 ′ and B2 ′ corresponding to the magnitude of the external magnetic field are known, the fluctuations of the magnetic field detection signal and the first angle signal φ can be calculated. Also, if the value of C1 is known, the fluctuation of the first angle signal φ can be calculated. Therefore, the abnormality diagnosis apparatus 1000 obtains in advance values such as A2 ′, B2 ′, and C1 corresponding to the magnitude of the external magnetic field, and stores them in the storage unit 1070 as correction values. The abnormality diagnosis device 1000 may store a plurality of correction values calculated from the measured magnitude of the external magnetic field in the storage unit 1070, complement the correction values, and store more correction values in the storage unit 1070. May be The interpolation may be linear interpolation or the like.

The correction unit 1060 may correct using the correction value as in the following equation.
(21)
Vx ′ = Vx−A2 ′ · cos (3θ)
Vy ′ = Vy−B2 ′ · sin (3θ)
φ '= φ-C1 · sin (4θ)

Next, the third abnormality determination unit 1080 determines whether the first angle signal φ ′ after the correction by the correction unit 1060 is properly corrected (S744). When the absolute value | φ′−ψ | of the difference between the corrected first angle signal φ ′ and the second angle signal 超 え exceeds the angle signal threshold θ _th , the third abnormality determination unit 1080 calculates the first angle signal. It is determined that φ is abnormal. That is, the third abnormality determination unit 1080 determines that an abnormality has occurred to such an extent that the first angle signal φ can not be corrected. Further, the third abnormality determination unit 1080 sets the first angle when the absolute value | φ′−ψ | of the difference between the corrected first angle signal φ ′ and the second angle signal ψ is less than or equal to the angle signal threshold θ _th. Signal φ is determined to be a correctable abnormality.

Next, the output unit 1090 outputs a second angle signal ψ (S746). Further, when | φ′−ψ | exceeds the angle signal threshold θ _th , the output unit 1090 outputs an error signal to the outside indicating that an abnormality that can not be corrected to the first angle signal φ occurs. You may Is less than or equal to the angle signal threshold θ _th , the output unit 1090 may externally output an error signal indicating that a correctable abnormality has occurred in the first angle signal φ. .

  As described above, the abnormality diagnosis apparatus 1000 of the modification according to the present embodiment can determine in more detail which of the first angle signal φ and the second angle signal 異常 has an abnormality. In addition, abnormality diagnosis apparatus 1000 of the present modification can determine whether first angle signal φ is equal to or greater than the amount that can be corrected, and can correct and output it if it can be corrected. .

  FIG. 9 shows a modification of the rotation angle measurement system 20 according to the present embodiment. In the rotation angle measurement system 20 of the present modification, substantially the same operations as those of the rotation angle measurement system 20 according to the present embodiment shown in FIG. 5 and the abnormality diagnosis apparatus 1000 according to the present embodiment shown in FIG. Are given the same reference numerals and explanation thereof is omitted.

  In the rotation angle measurement system 20 of the present modification, the first signal detection device 200 executes the correction of the first angle signal φ. In this case, the second signal detection device 400 supplies the amplitude signal A (ψ) to the first signal detection device 200 and the abnormality diagnosis device 1000. The first signal detection device 200 corrects the first angle signal φ detected by the angle detection unit 220 when the received amplitude signal A (ψ) satisfies the first condition. The first signal detection device 200 further includes a correction unit 1060 and a storage unit 1070.

  The correction unit 1060 corrects the first angle signal φ using the correction value stored in the storage unit 1070. The correction operation of the correction unit 1060 has been described with reference to FIG. The correction unit 1060 supplies the corrected first angle signal φ ′ to the third abnormality determination unit 1080 of the abnormality diagnosis device 1000.

  When the amplitude signal A (ψ) satisfies the first condition, the abnormality diagnosis device 1000 receives the corrected first angle signal φ ′ from the first signal detection device 200. The third abnormality determination unit 1080 determines whether or not the received corrected first angle signal φ ′ has been corrected normally. The operations of the third abnormality determination unit 1080 and the output unit 1090 have been described with reference to FIG. As described above, the rotation angle measurement system 20 of the present modification can correct and output the first angle signal φ detected by the first signal detection device 200.

  In the rotation angle measurement system 20 according to the present embodiment described above, the second angle signal 400 is updated and output so that the second signal detection device 400 has a type 2 servo circuit and the angle error signal ε approaches zero. An example has been described. In addition to this, the rotation angle measurement system 20 updates and outputs the first angle signal φ so that the first signal detection device 200 also has a type 2 servo circuit, and brings the angle error signal ε closer to 0. It is also good. Also, instead of this, the first signal detection device 200 and the second signal detection device 400 may output the angle signal and the amplitude signal by another circuit.

  FIG. 10 shows a first modification of the first signal detection device 200 and the second signal detection device 400 according to the present embodiment, together with the first rotation angle sensor 100 and the first signal detection device 200. The first signal detection device 200 and the second signal detection device 400 of the first modification may output an angle signal and an amplitude signal using an algorithm. The first signal detection apparatus 200 includes an AD conversion unit 210, an AD conversion unit 212, a filter unit 230, a filter unit 232, and a first calculation unit 240. The AD conversion unit 210 and the AD conversion unit 212 are substantially the same as the operation described with reference to FIG.

  The filter unit 230 filters the digital data received from the AD conversion unit 210. The filter unit 232 filters the digital data received from the AD conversion unit 212. The filter unit 230 and the filter unit 232 may be decimation filters and may perform digital data thinning processing.

  The first operation unit 240 includes a CORDIC (Coordinate Rotation Digital Computing) circuit. The CORDIC circuit calculates an angle signal φ from the input signal based on an algorithm that performs various operations such as trigonometric function, multiplication, and division. The CORDIC circuit may be an integrated circuit such as a field-programmable gate array (FPGA) and an application specific integrated circuit (ASIC) on which the CORDIC algorithm is mounted.

  The second signal detection apparatus 400 includes a first switching unit 410, a second switching unit 412, an amplification unit 420, an amplification unit 422, an AD conversion unit 430, an AD conversion unit 432, a filter unit 510, a filter unit 512, and a second operation. It has a part 520. The first switching unit 410, the second switching unit 412, the amplification unit 420, the amplification unit 422, the AD conversion unit 430, and the AD conversion unit 432 are substantially the same as the operations described with reference to FIG.

  The filter unit 510 filters digital data received from the AD conversion unit 430. The filter unit 512 filters the digital data received from the AD conversion unit 432. The filter unit 510 and the filter unit 512 may be decimation filters and may perform digital data thinning processing.

  Second operation unit 520 includes a CORDIC circuit. The CORDIC circuit calculates an angle signal ψ and an amplitude signal A (ψ) from an input signal based on an algorithm that performs various operations such as trigonometric function, multiplication, and division. The CORDIC circuit may be an integrated circuit such as an FPGA or an ASIC equipped with a CORDIC algorithm. The first signal detection device 200 and the second signal detection device 400 can also be realized using such an integrated circuit.

  FIG. 11 shows a second modification of the first signal detection device 200 and the second signal detection device 400 according to the present embodiment, together with the first rotation angle sensor 100 and the first signal detection device 200. The first signal detection device 200 and the second signal detection device 400 of the second modification may output an angle signal and an amplitude signal using a vector sequential rotation circuit. The first signal detection apparatus 200 includes a filter unit 250, a filter unit 252, and a first circuit 260.

  The filter unit 250 filters the analog signal received from the first sensor 110. The filter unit 252 filters the analog signal received from the second sensor 120. The filter unit 250 and the filter unit 252 may be low-pass filters and may attenuate frequency components exceeding a predetermined frequency.

  The first circuit 260 includes a vector sequential rotation circuit. The vector sequential rotation circuit implements an algorithm that sequentially updates a representative vector while rotating a representative vector from vector data supplied one after another, and calculates an angle signal φ from an input signal. The first circuit 260 may output an angle signal φ of a digital signal.

  The second signal detection apparatus 400 includes a first switching unit 410, a second switching unit 412, an amplification unit 420, an amplification unit 422, a filter unit 530, a filter unit 532, and a second circuit 540. The first switching unit 410, the second switching unit 412, the amplification unit 420, and the amplification unit 422 are substantially the same as the operations described with reference to FIG.

  The filter unit 530 filters the analog signal received from the third sensor 310. The filter unit 532 filters the analog signal received from the fourth sensor 320. The filter unit 530 and the filter unit 532 may be low-pass filters and may attenuate frequency components exceeding a predetermined frequency.

  The second circuit 540 includes a vector sequential rotation circuit. The vector sequential rotation circuit implements an algorithm that sequentially updates a representative vector while rotating a representative vector from sequentially provided vector data, and calculates an angle signal ψ and an amplitude signal A (A) from an input signal. The second circuit 540 may output an angle signal ψ and an amplitude signal A (ψ) of the digital signal. The first signal detection device 200 and the second signal detection device 400 can also be realized using such a circuit.

  FIG. 12 shows an example of a hardware configuration of a computer 1900 that functions as the abnormality diagnosis apparatus 1000 according to the present embodiment. The computer 1900 according to this embodiment is connected to the host controller 2082 by the input / output controller 2084 and the CPU peripheral unit having the CPU 2000, the RAM 2020, the graphic controller 2075, and the display device 2080 mutually connected by the host controller 2082. An I / O unit having a communication interface 2030, a hard disk drive 2040, and a DVD drive 2060, and a legacy I / O unit having a ROM 2010, a flexible disk drive 2050, and an I / O chip 2070 connected to the I / O controller 2084; Equipped with

  The host controller 2082 connects the RAM 2020 to the CPU 2000 and the graphic controller 2075 which access the RAM 2020 at a high transfer rate. The CPU 2000 operates based on the programs stored in the ROM 2010 and the RAM 2020 to control each part. The graphic controller 2075 acquires image data generated by the CPU 2000 or the like on a frame buffer provided in the RAM 2020 and causes the display device 2080 to display the image data. Instead of this, the graphic controller 2075 may internally include a frame buffer for storing image data generated by the CPU 2000 or the like.

  The input / output controller 2084 connects the host controller 2082 with the communication interface 2030, the hard disk drive 2040, and the DVD drive 2060, which are relatively high-speed input / output devices. The communication interface 2030 communicates with other devices via a network. The hard disk drive 2040 stores programs and data used by the CPU 2000 in the computer 1900. The DVD drive 2060 reads a program or data from the DVD-ROM 2095 and provides it to the hard disk drive 2040 via the RAM 2020.

  Further, to the input / output controller 2084, the ROM 2010, the flexible disk drive 2050, and relatively low-speed input / output devices of the input / output chip 2070 are connected. The ROM 2010 stores a boot program executed when the computer 1900 starts up, and / or a program depending on the hardware of the computer 1900, and the like. The flexible disk drive 2050 reads a program or data from the flexible disk 2090 and provides it to the hard disk drive 2040 via the RAM 2020. The input / output chip 2070 connects the flexible disk drive 2050 to the input / output controller 2084 and, for example, inputs / outputs various input / output devices via parallel port, serial port, keyboard port, mouse port, etc. Connect to the controller 2084.

  The program provided to the hard disk drive 2040 via the RAM 2020 is stored in a recording medium such as the flexible disk 2090, the DVD-ROM 2095, or an IC card and provided by the user. The program is read from the recording medium, installed in the hard disk drive 2040 in the computer 1900 via the RAM 2020, and executed by the CPU 2000.

  The program is installed in the computer 1900, and the computer 1900 includes a first acquisition unit 1010, a second acquisition unit 1020, a first abnormality determination unit 1030, a correlation signal calculation unit 1040, a second abnormality determination unit 1050, a correction unit 1060, and a storage unit. 1070 to function as the third abnormality determination unit 1080 and the output unit 1090.

  The information processing described in the program is read by the computer 1900, and the first acquisition unit 1010, the second acquisition unit 1020, and the second acquisition unit are specific means in which the software and the various hardware resources described above cooperated. 1 functions as an abnormality determination unit 1030, a correlation signal calculation unit 1040, a second abnormality determination unit 1050, a correction unit 1060, a storage unit 1070, a third abnormality determination unit 1080, and an output unit 1090. And, by realizing calculation or processing of information according to the purpose of use of the computer 1900 in this embodiment by this specific means, a unique abnormality diagnosis device 1000 according to the purpose of use is constructed.

  As an example, when communication is performed between the computer 1900 and an external device etc., the CPU 2000 executes the communication program loaded on the RAM 2020, and based on the processing content described in the communication program, the communication interface It instructs communication processing to 2030. Under the control of the CPU 2000, the communication interface 2030 reads out transmission data stored in a transmission buffer area or the like provided on a storage device such as the RAM 2020, the hard disk drive 2040, the flexible disk 2090, or the DVD-ROM 2095 to the network. Alternatively, it writes data received or received from the network into a reception buffer area or the like provided on the storage device. As described above, the communication interface 2030 may transfer transmission / reception data to / from the storage device by the DMA (direct memory access) method, and instead, the storage device or communication interface 2030 of the transfer source from the CPU 2000. The transmission / reception data may be transferred by reading the data from the memory and writing the data to the communication interface 2030 or storage device of the transfer destination.

  In addition, the CPU 2000 may use all or necessary portions of files or databases stored in an external storage device such as a hard disk drive 2040, a DVD drive 2060 (DVD-ROM 2095), a flexible disk drive 2050 (flexible disk 2090). Are read into the RAM 2020 by DMA transfer or the like, and various processing is performed on the data on the RAM 2020. Then, the CPU 2000 writes the processed data back to the external storage device by DMA transfer or the like. In such processing, the RAM 2020 can be considered to temporarily hold the contents of the external storage device, so in the present embodiment, the RAM 2020 and the external storage device are collectively referred to as a memory, a storage unit, or a storage device. Various kinds of information such as various kinds of programs, data, tables, databases, and the like in the present embodiment are stored on such a storage device and become an object of information processing. The CPU 2000 can hold a part of the RAM 2020 in a cache memory, and can read and write on the cache memory. Even in such a mode, since the cache memory takes part of the function of the RAM 2020, in the present embodiment, the cache memory is also included in the RAM 2020, the memory, and / or the storage device unless otherwise indicated. Do.

  In addition, the CPU 2000 performs various operations described in this embodiment on data read from the RAM 2020 and specified by a program instruction sequence, including various operations, information processing, condition determination, information search / replacement, etc. And write back to the RAM 2020. For example, in the case where the CPU 2000 makes a condition determination, whether the various variables described in the present embodiment satisfy the condition such as greater than, less than, equal to, or less than or equal to other variables or constants. If the condition is satisfied (or not satisfied), branch to a different instruction sequence or call a subroutine.

  The CPU 2000 can also search information stored in a file or database in the storage device. For example, in the case where a plurality of entries in which the attribute value of the second attribute is associated with the attribute value of the first attribute are stored in the storage device, the CPU 2000 can generate a plurality of entries stored in the storage device. Search for an entry that matches the condition for which the attribute value of the first attribute is specified from among them, and by reading out the attribute value of the second attribute stored in the entry, it is associated with the first attribute that satisfies the predetermined condition An attribute value of the second attribute can be obtained.

  The programs or modules described above may be stored in an external recording medium. As the recording medium, in addition to the flexible disk 2090, the DVD-ROM 2095, an optical recording medium such as DVD, Blu-ray (registered trademark) or CD, a magneto-optical recording medium such as MO, a tape medium, a semiconductor such as an IC card A memory or the like can be used. Alternatively, a storage device such as a hard disk or a RAM provided in a server system connected to a dedicated communication network or the Internet may be used as a recording medium, and the program may be provided to the computer 1900 via the network.

  As mentioned above, although this invention was demonstrated using embodiment, the technical scope of this invention is not limited to the range as described in the said embodiment. It is apparent to those skilled in the art that various changes or modifications can be added to the above embodiment. It is also apparent from the scope of the claims that the embodiments added with such alterations or improvements can be included in the technical scope of the present invention.

The execution order of each process such as operations, procedures, steps, and steps in the apparatuses, systems, programs, and methods shown in the claims, the specification, and the drawings is particularly “before”, “preceding” It is to be noted that “it is not explicitly stated as“ etc. ”and can be realized in any order as long as the output of the previous process is not used in the later process. With regard to the flow of operations in the claims, the specification and the drawings, even if it is described using “first,” “next,” etc. for convenience, it means that it is essential to carry out in this order. It is not a thing.
According to the present application, the following items are also disclosed.
(Item 1)
A first acquisition unit that acquires a first angle signal of a rotating body, which is output by a first signal detection device according to a detection signal of a first rotation angle sensor that detects magnetic fields in at least two different directions;
A second acquisition unit that acquires a second angle signal and an amplitude signal of the rotating body, which is output by a second signal detection device according to a detection signal of a second rotation angle sensor that detects magnetic fields in at least two different directions;
A first abnormality determination unit that determines an abnormality of the first angle signal based on the amplitude signal;
Equipped with
Abnormality diagnosis device.
(Item 2)
The first abnormality determination unit determines that at least the first angle signal is abnormal when the amplitude signal is smaller than a first threshold or the amplitude signal is larger than a second threshold larger than the first threshold. The abnormality diagnosis device according to 1.
(Item 3)
The first abnormality determination unit determines whether the amplitude signal is greater than or equal to a 0th threshold smaller than the first threshold and less than the first threshold, or the amplitude signal is greater than the second threshold, and The abnormality diagnosis device according to Item 2, wherein the first angle signal is determined to be abnormal when a first condition equal to or less than a third threshold value, which is larger than a second threshold value, is determined.
(Item 4)
The first abnormality determination unit determines whether the first angle signal and the second angle signal are lower if the amplitude signal satisfies the second condition which is smaller than the zeroth threshold or the amplitude signal is larger than the third threshold. The abnormality diagnosis device according to Item 3, which determines an abnormality.
(Item 5)
The first abnormality determination unit determines that the first angle signal or the second angle signal is abnormal when the amplitude signal satisfies a third condition which is equal to or more than the first threshold and equal to or less than the second threshold. The abnormality diagnosis device according to Item 3 or 4.
(Item 6)
A correlation signal calculation unit that calculates a correlation signal between a measured signal based on the amplitude signal and a predetermined periodic signal;
A second abnormality determination unit that determines an abnormality of a second angle signal based on the correlation signal;
The abnormality diagnosis device according to any one of Items 3 to 5, comprising:
(Item 7)
The abnormality diagnosis device according to Item 6, wherein the correlation signal calculation unit performs Fourier transform on the amplitude signal to calculate the correlation signal.
(Item 8)
The abnormality diagnosis device according to Item 6 or 7, wherein the second abnormality determination unit determines that the second angle signal is abnormal when the absolute value of the correlation signal exceeds a correlation signal threshold.
(Item 9)
The correction method according to any one of items 3 to 8, further comprising: a correction unit configured to correct a first angle signal output from the first signal detection device based on the amplitude signal when the amplitude signal satisfies the first condition. Abnormality diagnosis device.
(Item 10)
The abnormality diagnosis device according to Item 9, wherein the correction unit corrects the detection signal of the first rotation angle sensor in accordance with the magnitude of the amplitude signal.
(Item 11)
The abnormality diagnosis device according to Item 9 or 10, comprising a storage unit corresponding to the magnitude of the amplitude signal and storing a correction value used by the correction unit for correction.
(Item 12)
When the absolute value of the difference between the first angle signal corrected by the correction unit and the second angle signal output by the second signal detection device exceeds an angle signal threshold, the first angle signal is determined to be abnormal The abnormality diagnosis device according to any one of Items 9 to 11, further comprising a third abnormality determination unit.
(Item 13)
When the absolute value of the difference between the first angle signal and the second angle signal exceeds an angle signal threshold value, the first abnormality determination unit performs the abnormality determination in any one of the items 1 to 12 Abnormality diagnosis device described.
(Item 14)
When one of the first angle signal and the second angle signal is determined to be abnormal, an angle signal output from the other of the first angle signal and the second angle signal is an angle signal of the rotating body. The abnormality diagnosis device according to any one of Items 1 to 13, further comprising an output unit configured to output as.
(Item 15)
A first rotation angle sensor for detecting magnetic fields in at least two different directions;
A first signal detection device that outputs a first angle signal of a rotating body according to a detection signal of the first rotation angle sensor;
A second rotation angle sensor for detecting magnetic fields in at least two different directions;
A second signal detection device that outputs a second angle signal and an amplitude signal of the rotating body according to a detection signal of the second rotation angle sensor;
Equipped with
The second rotation angle sensor is an angle detection device in which a dynamic range of an input magnetic field is larger than that of the first rotation angle sensor.
(Item 16)
The first rotation angle sensor includes a magnetoresistive element.
16. The angle detection device according to item 15, wherein the second rotation angle sensor has a Hall element.
(Item 17)
15. The angle detection device according to Item 15 or 16, wherein the second signal detection device outputs the amplitude signal for determining an abnormality of the first angle signal output by the first signal detection device.
(Item 18)
Acquiring a first angle signal of the rotating body, which is output by the first signal detection device according to the detection signal of the first rotation angle sensor which detects magnetic fields in at least two different directions;
Acquiring a second angle signal and an amplitude signal of the rotating body, which is output by a second signal detection device according to a detection signal of a second rotation angle sensor that detects magnetic fields in at least two different directions;
Determining an abnormality of the first angle signal based on the amplitude signal;
Equipped with
Abnormality diagnosis method.
(Item 19)
The step of determining an abnormality of the first angle signal includes performing an abnormality determination when an absolute value of a difference between the first angle signal and the second angle signal exceeds an angle signal threshold. Abnormality diagnosis method.
(Item 20)
In the step of determining the abnormality of the first angle signal, the amplitude signal is greater than or equal to a zero threshold and less than a first threshold greater than the zero threshold, or the amplitude signal is greater than the first threshold. The abnormality diagnosis method according to items 18 and 19, wherein the first angle signal is determined to be abnormal when a first condition which is larger than the second threshold value and equal to or less than a third threshold value larger than the second threshold value is satisfied.
(Item 21)
In the step of determining the abnormality of the first angle signal, when the amplitude signal satisfies a second condition smaller than the zeroth threshold or the amplitude signal satisfies a second condition larger than the third threshold, the first angle signal and the first angle signal are determined. The abnormality diagnosis method according to Item 20, wherein the second angle signal is determined to be abnormal.
(Item 22)
In the step of determining the abnormality of the first angle signal, the first angle signal or the second angle signal is satisfied when the amplitude signal satisfies a third condition which is equal to or more than the first threshold and equal to or less than the second threshold. The abnormality diagnosis method according to Item 20 or 21, wherein it is determined that the abnormality is abnormal.
(Item 23)
When the amplitude signal satisfies the third condition and the first angle signal or the second angle signal is determined to be abnormal,
Calculating a correlation signal between the measured signal based on the amplitude signal and a predetermined periodic signal;
Determining an abnormality of the second angle signal based on the correlation signal;
The abnormality diagnosis method according to item 22, comprising:
(Item 24)
The abnormality diagnosis method according to Item 23, wherein the step of calculating the correlation signal performs Fourier transform on the amplitude signal to calculate the correlation signal.
(Item 25)
The abnormality diagnosis method according to Item 23 or 24, wherein, in the step of determining the abnormality of the second angle signal, the second angle signal is determined to be abnormal when the absolute value of the correlation signal exceeds a correlation signal threshold.
(Item 26)
When the amplitude signal satisfies the first condition, the method according to any one of items 20 to 25 further comprising: correcting the first angle signal output from the second signal detection device based on the amplitude signal. Abnormality diagnosis method.
(Item 27)
The abnormality diagnosis method according to Item 26, wherein the step of correcting the first angle signal corrects the detection signal of the first rotation angle sensor according to the magnitude of the amplitude signal.
(Item 28)
The abnormality diagnosis method according to Item 26 or 27, wherein the step of correcting the first angle signal corrects the first angle signal using a correction value corresponding to the magnitude of the amplitude signal.
(Item 29)
If the absolute value of the difference between the first angle signal corrected by the step of correcting the first angle signal and the second angle signal output by the second signal detection device exceeds an angle signal threshold, the first The abnormality diagnosis method according to any one of items 26 to 28, further comprising the step of determining that the angle signal is abnormal.
(Item 30)
When one of the first angle signal and the second angle signal is determined to be abnormal, an angle signal output from the other of the first angle signal and the second angle signal is an angle signal of the rotating body. 30. The abnormality diagnosis method according to any one of items 18 to 29, further comprising the step of: outputting.
(Item 31)
The program which makes a computer perform the abnormality-diagnosis method as described in any one of item 18-30.

DESCRIPTION OF SYMBOLS 10 magnetoresistive element, 12 pinned layer, 14 insulating layer, 16 free layer, 20 rotation angle measurement system, 100 1st rotation angle sensor, 110 1st sensor, 112 1st magnetoresistive element, 114 2nd magnetoresistive element, 116 Third magnetoresistance element, 118 fourth magnetoresistance element, 120 second sensor, 122 fifth magnetoresistance element, 124 sixth magnetoresistance element, 126 seventh magnetoresistance element, 128 eighth magnetoresistance element, 200 first signal Detection device, 210 AD conversion unit, 212 AD conversion unit, 220 angle detection unit, 230 filter unit, 232 filter unit, 240 first operation unit, 250 filter unit, 252 filter unit, 260 first circuit, 300 second rotation angle Sensor, 310 third sensor, 320 fourth sensor, 400 second signal detection device, 410 first switching unit, 41 Second switching unit, 420 amplification unit, 422 amplification unit, 430 AD conversion unit, 432 AD conversion unit, 440 first multiplication unit, 450 loop filter, 460 angle updating unit, 470 storage unit, 480 second multiplication unit, 490 Integration Unit, 510 filter unit, 512 filter unit, 520 second operation unit, 530 filter unit, 532 filter unit, 540 second circuit, 1000 abnormality diagnosis device, 1010 first acquisition unit, 1020 second acquisition unit, 1030 first abnormality Judgment unit, 1040 correlation signal calculation unit, 1050 second abnormality judgment unit, 1060 correction unit, 1070 storage unit, 1080 third abnormality judgment unit, 1090 output unit, 1900 computer, 2000 CPU, 2010 ROM, 2020 RAM, 2030 communication interface , 2040 hard disk drive 2050 flexible disk drive, 2060 DVD drive, 2070 input / output chip, 2075 graphic controller, 2080 display device, 2082 host controller, 2084 input / output controller, 2090 flexible disk, 2095 DVD-ROM

Claims (27)

A first acquisition unit that acquires a first angle signal of a rotating body, which is output by a first signal detection device according to a detection signal of a first rotation angle sensor that detects magnetic fields in at least two different directions;
A second acquisition unit that acquires a second angle signal and an amplitude signal of the rotating body, which is output by a second signal detection device according to a detection signal of a second rotation angle sensor that detects magnetic fields in at least two different directions;
A first abnormality determination unit that determines an abnormality of the first angle signal based on the amplitude signal;
Equipped with
The first abnormality determination unit determines that the first angle signal is abnormal if the amplitude signal is smaller than a first threshold or the amplitude signal is larger than a second threshold larger than the first threshold. apparatus. The first abnormality determination unit determines whether the amplitude signal is greater than or equal to a 0th threshold smaller than the first threshold and less than the first threshold, or the amplitude signal is greater than the second threshold, and if the third threshold value or less in the first condition is satisfied is greater than the second threshold value, the abnormality diagnostic device according to judges claim 1 wherein the first angle signal is abnormal. The first abnormality determination unit determines whether the first angle signal and the second angle signal are lower if the amplitude signal satisfies the second condition which is smaller than the zeroth threshold or the amplitude signal is larger than the third threshold. The abnormality diagnosis device according to claim 2, wherein it is determined that the abnormality is present. The first abnormality determination unit determines that the first angle signal or the second angle signal is abnormal when the amplitude signal satisfies a third condition which is equal to or more than the first threshold and equal to or less than the second threshold. The abnormality diagnosis device according to claim 2 or 3 . A correlation signal calculation unit that calculates a correlation signal between a measured signal based on the amplitude signal and a predetermined periodic signal;
A second abnormality determination unit that determines an abnormality of a second angle signal based on the correlation signal;
The abnormality diagnosis device according to any one of claims 2 to 4 , comprising: The abnormality diagnosis device according to claim 5 , wherein the correlation signal calculation unit calculates the correlation signal by performing Fourier transform on the amplitude signal. The second abnormality determination unit, wherein when the absolute value of the correlation signal exceeds a correlation signal threshold, the abnormality diagnostic device according to claim 5 or 6 determines the second angle signal abnormal. The correction device according to any one of claims 2 to 7 , further comprising: a correction unit configured to correct a first angle signal output from the first signal detection device based on the amplitude signal when the amplitude signal satisfies the first condition. Abnormality diagnosis device. The abnormality diagnosis device according to claim 8 , wherein the correction unit corrects a detection signal of the first rotation angle sensor according to a magnitude of the amplitude signal. Wherein corresponding to the magnitude of the amplitude signal, the correction unit abnormality diagnosis apparatus according to claim 8 or 9 comprising a storage unit that stores a correction value used for correction. When the absolute value of the difference between the first angle signal corrected by the correction unit and the second angle signal output by the second signal detection device exceeds an angle signal threshold, the first angle signal is determined to be abnormal The abnormality diagnosis device according to any one of claims 8 to 10 , further comprising a third abnormality determination unit. Said first abnormality determination unit, the absolute value of the difference between the first angle signal and the second angle signal, if it exceeds the angle signal threshold, any one of claims 1 to 11 to perform the determination of abnormality The abnormality diagnosis device described in. When one of the first angle signal and the second angle signal is determined to be abnormal, an angle signal output from the other of the first angle signal and the second angle signal is an angle signal of the rotating body. The abnormality diagnosis device according to any one of claims 1 to 12 , further comprising an output unit configured to output as. Acquiring a first angle signal of the rotating body, which is output by the first signal detection device according to the detection signal of the first rotation angle sensor which detects magnetic fields in at least two different directions;
Acquiring a second angle signal and an amplitude signal of the rotating body, which is output by a second signal detection device according to a detection signal of a second rotation angle sensor that detects magnetic fields in at least two different directions;
Determining an abnormality of the first angle signal based on the amplitude signal;
Equipped with
In the step of determining the abnormality of the first angle signal, the first angle signal is abnormal if the amplitude signal is smaller than a first threshold or the amplitude signal is larger than a second threshold larger than the first threshold. Abnormality diagnosis method to determine The abnormality determining step of the first angle signal, the amplitude signal is small 0th threshold higher than the first threshold value, and, before Symbol less than the first threshold value, or the amplitude signal before Symbol second threshold The abnormality diagnosis method according to claim 14 , wherein the first angle signal is determined to be abnormal if a first condition which is larger than the third threshold value and larger than the second threshold value is satisfied. In the step of determining the abnormality of the first angle signal, when the amplitude signal satisfies a second condition smaller than the zeroth threshold or the amplitude signal satisfies a second condition larger than the third threshold, the first angle signal and the first angle signal are determined. The abnormality diagnosis method according to claim 15 , wherein the second angle signal is determined to be abnormal. In the step of determining the abnormality of the first angle signal, the first angle signal or the second angle signal is satisfied when the amplitude signal satisfies a third condition which is equal to or more than the first threshold and equal to or less than the second threshold. The abnormality diagnosis method according to claim 15 or 16 , wherein the abnormality is determined to be abnormal. When the amplitude signal satisfies the third condition and the first angle signal or the second angle signal is determined to be abnormal,
Calculating a correlation signal between the measured signal based on the amplitude signal and a predetermined periodic signal;
Determining an abnormality of the second angle signal based on the correlation signal;
The abnormality diagnosis method according to claim 17 , comprising: The abnormality diagnosis method according to claim 18 , wherein the step of calculating the correlation signal Fourier-transforms the amplitude signal to calculate the correlation signal. The abnormality determining step of the second angle signal, when the absolute value of the correlation signal exceeds a correlation signal threshold, the abnormality diagnostic method according to claim 18 or 19 determines the second angle signal abnormal. 21. The method according to any one of claims 15 to 20 , comprising the step of correcting the first angle signal output by the second signal detection device based on the amplitude signal when the amplitude signal satisfies the first condition. Method of diagnosis of 22. The abnormality diagnosis method according to claim 21 , wherein the step of correcting the first angle signal corrects the detection signal of the first rotation angle sensor in accordance with the magnitude of the amplitude signal. It said step of correcting the first angle signal, the abnormality diagnostic method according to claim 21 or 22 corrects the first angle signal using a correction value corresponding to the magnitude of the amplitude signal. If the absolute value of the difference between the first angle signal corrected by the step of correcting the first angle signal and the second angle signal output by the second signal detection device exceeds an angle signal threshold, the first The abnormality diagnostic method according to any one of claims 21 to 23 , further comprising the step of determining that the angle signal is abnormal. The step of determining an abnormality in the first angle signal executes an abnormality determination when an absolute value of a difference between the first angle signal and the second angle signal exceeds an angle signal threshold value. The abnormality diagnosis method according to any one of the above. When one of the first angle signal and the second angle signal is determined to be abnormal, an angle signal output from the other of the first angle signal and the second angle signal is an angle signal of the rotating body. 26. The abnormality diagnosis method according to any one of claims 14 to 25 , further comprising the step of: outputting. A program that causes a computer to execute the abnormality diagnosis method according to any one of claims 14 to 26 .

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