JP2016061708A - Calibration method of rotation angle sensor, calibration method of rotation angle sensor module, calibration parameter generation device, rotation angle sensor, rotation angle sensor module and program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce an angle non-linearity error specific to a rotation angle sensor and the angle non-linearity error occurring when the rotation angle sensor is assembled.SOLUTION: A calibration method of a rotation angle sensor detects a magnetic field in an X-axis direction on an X-Y plane, and a magnetic field in a Y-axis direction thereon, and detects a rotation angle on the X-Y plane of a rotation magnet rotating around a rotation axis. The calibration method of the rotation angle sensor and program are provided that comprise: an installation stage of installing the rotation angle sensor on the X-Y plane; a magnetic field application stage of, on the X-Y plane, applying to the rotation angle sensor the magnetic fields in N directions (N is an integer equal to three or more) different by an angle obtained by dividing a 360-degree angle into N equal angles, respectively; an acquisition stage of acquiring an output signal to be output in response to each application of the magnetic field in the N direction thereto; a calculation stage of calculating a calibration parameter calibrating the rotation angle sensor on the basis of the output signal; and a storage stage of causing a storage unit of the rotation angle sensor to store the calibration parameter.SELECTED DRAWING: Figure 13

Description

  The present invention relates to a rotation angle sensor calibration method, a rotation angle sensor module calibration method, a calibration parameter generation device, a rotation angle sensor, a rotation angle sensor module, and a program.

Conventionally, a non-contact rotation angle sensor that detects a change in a magnetic field in the X direction and the Y direction and detects a rotation angle of a rotating magnet based on the detection result has been known. And since such a rotation angle sensor has an angle nonlinearity error, adjustment and calibration of an error, etc. were performed (for example, refer to patent documents 1-6).
Patent Document 1 Japanese Patent Publication No. 2002-71381 Patent Document 2 US Patent Application Publication No. 2006/0290545 Patent Document 3 JP 2011-158488 A Patent Document 4 International Publication No. 2007/031167 Patent Document 5 JP 2012 JP-A No. 181188 Patent Document 6 JP 2007-304000 A

  However, when the calibrated rotation angle sensor is combined with a magnet or the like as the rotation angle sensor module, if an assembly error or the like occurs in the arrangement with the magnet, an angle nonlinearity error is caused by the assembly error. Therefore, a method and an apparatus for easily calibrating the angular nonlinearity error of the rotation angle sensor and the angular nonlinearity error generated when assembled as a module have been desired.

  In the first aspect of the present invention, the rotation angle sensor detects the rotation angle in the XY plane of the rotating magnet that rotates around the rotation axis by detecting the magnetic field in the X-axis direction and the magnetic field in the Y-axis direction on the XY plane. In a calibration method, a magnetic field in an N direction (N is an integer of 3 or more) having different directions by an angle equal to 360 degrees divided into N on the XY plane and an installation stage in which the rotation angle sensor is installed on the XY plane, A magnetic field application step for applying to each rotation angle sensor, an acquisition step for acquiring an output signal output in response to each application of a magnetic field in the N direction from the rotation angle sensor, and a rotation angle sensor based on the output signal A rotation angle sensor calibration method and program comprising: a calculation step for calculating a calibration parameter to be calibrated; and a storage step for storing the calibration parameter in a storage unit of the rotation angle sensor.

  In the second aspect of the present invention, the rotation angle of the rotating magnet in the XY plane is detected by detecting the rotating magnet rotating around the rotation axis, the magnetic field in the X-axis direction on the XY plane, and the magnetic field in the Y-axis direction. A rotation angle sensor module comprising a rotation angle sensor, wherein the rotation magnet is rotated by 360 degrees by an angle equal to N, and magnetic fields in N directions (N is an integer of 3 or more) having different directions are rotated. A magnetic field application step for applying to the rotation angle sensor; an acquisition step for acquiring an output signal output in response to each application of a magnetic field in the N direction; and a rotation angle sensor based on the output signal. A calculation method for calculating a calibration parameter for calibrating the rotation angle sensor, and a storage step for storing the calibration parameter in a storage unit of the rotation angle sensor. To provide.

  In the third aspect of the present invention, the rotation angle sensor detects the rotation angle in the XY plane of the rotating magnet that rotates around the rotation axis by detecting the magnetic field in the X-axis direction and the magnetic field in the Y-axis direction on the XY plane. An acquisition unit that acquires an output signal, a calculation unit that calculates a calibration parameter for calibrating the rotation angle sensor based on the output signal, a parameter supply unit that supplies and stores the calibration parameter in the storage unit of the rotation angle sensor, The acquisition unit outputs in response to application of magnetic fields in N directions (N is an integer of 3 or more) having different directions by an angle obtained by equally dividing 360 degrees into N on the XY plane. Provided is a calibration parameter generation device that obtains an output signal to be output from a rotation angle sensor.

  In the fourth aspect of the present invention, an X-axis signal output unit that outputs a magnetic field detection signal in the X-axis direction by magnetoelectrically converting the magnetic field in the X-axis direction, and a Y-axis direction by magnetoelectrically converting the magnetic field in the Y-axis direction. A Y-axis signal output unit that outputs a magnetic field detection signal of the sensor, a storage unit that stores at least one calibration parameter for calibrating the error of the angle signal, and magnetic fields in the X-axis direction and the Y-axis direction based on the calibration parameter An error correction unit that corrects an error in the detection signal and outputs error correction signals in the X-axis direction and the Y-axis direction, and a corrected angle signal is calculated based on the error correction signals in the X-axis direction and the Y-axis direction. An angle signal calculation unit and a rotation angle sensor and a rotation angle sensor module are provided.

  In the fifth aspect of the present invention, an X-axis signal output unit that outputs a magnetic field detection signal in the X-axis direction by magnetoelectrically converting the magnetic field in the X-axis direction, and a Y-axis direction by magnetoelectrically converting the magnetic field in the Y-axis direction. A Y-axis signal output unit that outputs a magnetic field detection signal of the X-axis, an angle signal calculation unit that calculates an angle signal based on the magnetic field detection signals in the X-axis direction and the Y-axis direction, and at least for calibrating the error of the angle signal Provided are a rotation angle sensor and a rotation angle sensor module including a storage unit that stores one calibration parameter, and an error correction unit that corrects an error of an angle signal based on the calibration parameter.

  It should be noted that the above summary of the invention does not enumerate all the necessary features of the present invention. In addition, a sub-combination of these feature groups can also be an invention.

The structural example of the rotation angle sensor 100 which concerns on this embodiment is shown. An example in which the first Hall element pair 110 according to the present embodiment detects a magnetic field in the first direction is shown. An example of the rotation angle sensor 100 is shown together with a schematic configuration of a circuit inside the rotation angle sensor 100. An example of the Hall electromotive force signal (V _X , V _Y ) having an offset V _{os —} x in the X-axis direction is shown. An example of the amplitude of the Hall electromotive force signal (V _X , V _Y ) having an offset V _{os_x} in the X-axis direction is shown. An example of an angular non-linearity error of a Hall electromotive force signal (V _X , V _Y ) having an offset V _{os —} x in the X-axis direction is shown. An example of the Hall electromotive force signal (V _X , V _Y ) having an offset V _{os_y} in the Y-axis direction is shown. An example of an angular non-linearity error of a Hall electromotive force signal (V _X , V _Y ) having an offset V _{os_y} in the Y-axis direction is shown. An example of Hall electromotive force signals (V _X , V _Y ) having a magnetic sensitivity mismatch is shown. An example of an angular nonlinearity error of Hall electromotive force signals (V _X , V _Y ) having a magnetic sensitivity mismatch is shown. An example of the Hall electromotive force signal (V _X , V _Y ) having a non-orthogonal error α is shown. An example of an angular non-linearity error of a Hall electromotive force signal (V _X , V _Y ) having a non-orthogonal error α will be shown. An example of the rotation angle sensor 100 according to the present embodiment is shown together with the calibration parameter generation device 200. The 1st operation | movement flow of the calibration parameter production | generation apparatus 200 which concerns on this embodiment is shown. A magnetic field application device 30 according to the present embodiment is shown together with a rotation angle sensor 100 and a calibration parameter generation device 200. The magnetic field application apparatus 30 which concerns on this embodiment shows the 1st example of the magnetic field applied to the rotation angle sensor 100. FIG. The magnetic field application apparatus 30 which concerns on this embodiment shows the 2nd example of the magnetic field applied to the rotation angle sensor 100. FIG. A modification of the rotation angle sensor 100 according to the present embodiment is shown together with a corresponding calibration parameter generation device 200. An example of the rotation angle sensor module 300 according to the present embodiment is shown together with the calibration parameter generation device 200. An example of an assembly error in which a center axis shift has occurred in the rotation angle sensor module 300 according to the present embodiment is shown. An example of an assembly error in which eccentricity has occurred in the rotation angle sensor module 300 according to the present embodiment is shown. An example of an assembly error in which the rotation magnet 410 is inclined in the rotation angle sensor module 300 according to the present embodiment is shown. The 2nd operation | movement flow of the calibration parameter production | generation apparatus 200 which concerns on this embodiment is shown. The 1st example of the rotation position of the rotating magnet 410 of this embodiment is shown. The 2nd example of the rotation position of the rotating magnet 410 of this embodiment is shown. An example in which magnetic fields in eight directions are applied to the rotation angle sensor 100 of the ideal rotation angle sensor module 300 will be described. The example which applied the magnetic field of 8 directions to the rotation angle sensor 100 of the rotation angle sensor module 300 which has an assembly error of a center axis | shaft deviation, respectively is shown. An example of the Hall electromotive force signal (V _X , V _Y ) having a center axis deviation is shown. An example of the result of having simulated the angle nonlinearity error which rotation angle sensor module 300 concerning this embodiment generates is shown. An example of a magnetic field detection signal (V _X (θ _n ), V _Y (θ _n )) acquired by the acquisition unit 210 according to the present embodiment from the rotation angle sensor 100 is shown. An example of the measurement result of the angle nonlinear error of the rotation angle sensor 100 according to the present embodiment is shown. The angular nonlinear error after the rotation angle sensor 100 which concerns on this embodiment performs calibration is shown. An example of the measurement result of the angle nonlinear error of the rotation angle sensor 100 according to the present embodiment is shown. The angular nonlinear error after the rotation angle sensor 100 which concerns on this embodiment performs calibration is shown. An example of a hardware configuration of a computer 1900 functioning as the calibration parameter generation apparatus 200 according to the present embodiment is shown.

  Hereinafter, the present invention will be described through embodiments of the invention, but the following embodiments do not limit the invention according to the claims. In addition, not all the combinations of features described in the embodiments are essential for the solving means of the invention.

  FIG. 1 shows a configuration example of a rotation angle sensor 100 according to the present embodiment. The rotation angle sensor 100 detects, for example, the rotation angle of a rotating magnet that rotates around the rotation axis in the vicinity of the sensor without contact. The rotation angle sensor 100 includes a substrate 10, a first Hall element pair 110, a second Hall element pair 120, and a magnetic convergence plate 130.

  The substrate 10 is formed of a semiconductor such as silicon and includes a semiconductor circuit and a semiconductor element. The substrate 10 may be an IC chip. In this case, the substrate 10 includes a terminal and is electrically connected to an external substrate, circuit, wiring, and the like. In FIG. 1, one surface of the substrate 10 is an XY plane having an X axis and a Y axis, and an axis perpendicular to the XY plane is a Z axis. That is, the X, Y, and Z axes are coordinate systems orthogonal to each other.

  The first Hall element pair 110 is formed on the substrate 10 and connected to a circuit or the like formed on the substrate 10. As an example, the first Hall element pair 110 is arranged in the first direction. Here, the first direction in the present embodiment is the X-axis direction (first axis) in FIG. The first Hall element pair 110 includes a first Hall element 112 and a second Hall element 114, and the two Hall elements are arranged in parallel to the X axis (for example, on the X axis).

  As an example, the first Hall element 112 and the second Hall element 114 are elements that generate an electromotive force (Hall effect) in the Y-axis direction corresponding to a magnetic field input in the Z-axis direction when a current flows in the X-axis direction. . The first hall element 112 and the second hall element 114 may be formed of a semiconductor or the like.

  As an example, the first Hall element 112 and the second Hall element 114 are arranged line-symmetrically with respect to the Y axis on the substrate 10. Alternatively, the first Hall element 112 and the second Hall element 114 may be arranged point-symmetrically with respect to the origin on the substrate 10. In the present embodiment, an example in which the first Hall element 112 and the second Hall element 114 are arranged symmetrically with respect to the Y axis will be described.

  Similar to the first Hall element pair 110, the second Hall element pair 120 is formed on the substrate 10 and connected to a circuit or the like formed on the substrate 10. For example, the second Hall element pair 120 is arranged in the second direction. Here, the second direction in the present embodiment is the Y-axis direction (second axis) in FIG. The third direction is the Z-axis direction (third axis) in FIG. The second Hall element pair 120 includes a third Hall element 122 and a fourth Hall element 124, and the two Hall elements are arranged in parallel to the Y axis (for example, on the Y axis).

  As an example, the third Hall element 122 and the fourth Hall element 124 are elements that generate an electromotive force (Hall effect) in the X-axis direction corresponding to a magnetic field input in the Z-axis direction when a current flows in the Y-axis direction. . As an example, the third Hall element 122 and the fourth Hall element 124 are arranged symmetrically with respect to the X axis on the substrate 10. Alternatively, the third Hall element 122 and the fourth Hall element 124 may be arranged point-symmetrically with respect to the origin on the substrate 10. In the present embodiment, an example in which the third Hall element 122 and the fourth Hall element 124 are arranged symmetrically with respect to the X axis will be described.

  The first Hall element pair 110 and the second Hall element pair 120 may be alternately energized in the X-axis direction and in the Y-axis direction in order to cancel the offset output. Such an offset canceling method is known as the Spinning Current method.

  The magnetic flux concentrating plate 130 is disposed above the first Hall element pair 110 and the second Hall element pair 120 and bends the magnetic field input to the rotation angle sensor 100. The magnetic converging plate 130 is formed of a magnetic material or the like, and for example, a first hole having a sensitivity in the Z-axis direction by bending a magnetic field in the X-axis direction and / or the Y-axis direction so as to generate a component in the Z-axis direction. Input is made to the element pair 110 and the second Hall element pair 120. The magnetic flux concentrating plate 130 may be formed on the upper surface of the substrate 10, or alternatively, may be formed above the substrate 10 via an insulating layer or the like.

  The above rotation angle sensor 100 outputs output signals (Hall electromotive force) from the first Hall element pair 110 and the second Hall element pair 120 to the outside. Here, output signals from the first Hall element pair 110 and the second Hall element pair 120 are output according to the rotation angle of the rotating magnet. The output signal will be described with reference to FIG.

  FIG. 2 shows an example in which the first Hall element pair 110 according to the present embodiment detects a magnetic field in the first direction. In FIG. 2, the horizontal direction (the horizontal direction of the paper surface) is the X axis, and the vertical direction (the vertical direction of the paper surface) is the Z axis direction.

Here, the magnetic field vector H (H _X , H _Y , H _Z ) input to the rotation angle sensor 100 is bent by the magnetic converging plate 130 and input to the first Hall element 112, the magnetic flux density vector B (Hall, X 1). Is expressed by the following equation using the magnetic permeability Mu (Hall, X1) at the position of the first Hall element 112. Here, the magnetic permeability Mu (Hall, X1) is a second-order tensor (matrix with 3 rows and 3 columns).

Similarly, the magnetic flux density vector B (Hall, X2) input to the second Hall element 114 is expressed by the following equation using the magnetic permeability Mu (Hall, X2) at the position of the second Hall element 114.

The first hall element 112 and the second hall element 114 detect a magnetic field in the Z-axis direction. Therefore, the first Hall element 112 and the second Hall element 114, as shown in the following equation, thereby to detect the magnetic flux density B _Z of the Z-axis direction that is bent by the magnetic flux concentrator 130.

Here, as shown in FIG. 2, an example in which a magnetic field vector H _in (H _X , 0, 0) _{in the} + X-axis direction is input above the rotation angle sensor 100 will be described. As an example, the magnetic converging plate 130 bends the input magnetic field as shown by a magnetic flux density vector B in the drawing, and causes the first Hall element 112 to input a magnetic flux in the + Z-axis direction.

Further, since the magnetic permeability of the magnetic flux concentrating plate 130 made of a magnetic material or the like is higher than the magnetic permeability of air, the magnetic flux in the magnetic converging plate 130 is compared with the magnetic flux density in the air. Density increases. For example, the magnetic flux density in the Z-axis direction at the position of the first Hall element 112 is approximately 1. as compared with the magnetic flux density obtained by multiplying the input magnetic field _HZ by the air permeability μ, as shown by the following equation. About 4 times higher.

Similarly, as an example, the magnetic flux concentrating plate 130 causes the second Hall element 114 to generate a magnetic flux in the −Z-axis direction, and the magnetic flux density in the Z-axis direction at the position of the second Hall element 114 is expressed by the following equation.

  The first Hall element 112 and the second Hall element 114 thus generate Hall electromotive force according to the magnetic flux density input in the Z-axis direction. Here, when the 1st Hall element 112 and the 2nd Hall element 114 are formed with substantially the same shape and the substantially same material, each magnetic sensitivity becomes substantially equal. Further, since the magnetic flux densities input to the first Hall element 112 and the second Hall element 114 are opposite to each other, the generated hall electromotive forces have different signs.

Therefore, when the magnetic sensitivity is S, the Hall electromotive force signal V _X of the first Hall element pair 110 is converted into the Hall electromotive force V _sig (Hall, X1) of the first Hall element 112 and the Hall electromotive force of the second Hall element 114. It can be defined as the following equation, which is the difference between the power V _sig (Hall, X2).

Thus, the rotation angle sensor 100 outputs the Hall electromotive force according to the magnetic field vector H _in (H _X , 0, 0) input in the X-axis direction by calculating the Hall electromotive force signal V _X. be able to. Further, since the Hall electromotive force signal V _X is the difference between the Hall electromotive forces of the Hall elements, the first Hall element 112 and the second Hall element 114 are in the same direction (+ Z axis direction or −Z axis direction), and The Hall electromotive force generated by the magnetic field having substantially the same absolute value is canceled out and becomes substantially zero.

That is, the rotation angle sensor 100 calculates the Hall electromotive force signal V _X , so that even if a magnetic field vector H _XZ (H _X , 0, H _Z ) in a direction parallel to the XZ plane is input, The Hall electromotive force corresponding to the magnetic field vector component H _X (H _X , 0, 0) can be calculated. The first Hall element 112 and the second Hall element 114 are insensitive to the magnetic field in the Y-axis direction, and the magnetic focusing plate 130 ideally converts the magnetic field in the Y-axis direction into the Z-axis direction. do not do. Therefore, the rotation angle sensor 100 calculates the Hall electromotive force signal V _X so that the three orthogonal components are not zero (in any direction) magnetic field vectors H _XYZ (H _X , H _Y , H _Z ). Is input, it is possible to detect the Hall electromotive force according to the component H _X (H _X , 0, 0) of the magnetic field vector in the X-axis direction.

Similarly, the second Hall element pair 120 arranged in the Y-axis direction can calculate the magnetic field in the Y-axis direction. In other words, the rotation angle sensor 100 uses the second Hall element pair 120 to calculate the Hall electromotive force signal V _Y of the following equation, so that the magnetic field vector H _XYZ (H _X , H _Y , H _Z ) is input. However, it is possible to calculate the Hall electromotive force according to the component H _Y (0, H _Y , 0) of the magnetic field vector in the Y-axis direction.

Similarly, the first Hall element 112 and the second Hall element 114 generate Hall electromotive force according to the magnetic flux density input in the Z-axis direction. Then, the Hall electromotive force signal _{V Z} of the first hall element pair 110, Hall electromotive force _V sig of the first Hall element 112 (Hall, X1) and Hall electromotive force _V sig of the second Hall element 114 (Hall, X2) May be calculated as the sum of. The rotation angle sensor 100 of the present embodiment will describe an example in which the Hall electromotive force signals V _X and V _Y are output, and the Hall electromotive force signal V _Z will be omitted, but the rotation angle sensor 100 is not related to the Hall electromotive force signal. for even V _Z, it may be output like the Hall electromotive force signal _{V X} and _{V Y.}

As described above, the rotation angle sensor 100 is based on the output signals of the first Hall element pair 110 and the second Hall element pair 120, and the X-axis component of the input magnetic field vector H _XYZ (H _X , H _Y , H _Z ). Hall electromotive force signals V _X and V _Y corresponding to H _X (H _X , 0,0) and Y axis component H _Y (0, H _Y , 0) are output. That is, the rotation angle sensor 100 can calculate the Hall electromotive force corresponding to the magnetic field in the direction parallel to the XY plane by decomposing it into an X-axis component and a Y-axis component.

The rotation angle sensor 100 can detect, for example, a magnetic field caused by rotation of a rotating magnet whose rotation axis is parallel to the Z axis in a plane parallel to the XY plane, and output a Hall electromotive force signal corresponding to the rotation angle. it can. For example, the rotation angle sensor 100 receives a rotating magnetic field expressed by the following equation. Here, H ₀ is the amplitude value of the magnetic field, and is a constant that may be normalized (for example, 1) when calculating the rotation angle θ.
(Equation 8)
H _X = H ₀ · cos θ
H _Y = H ₀ · sin θ

As an example, the rotation angle sensor 100 outputs a Hall electromotive force signal (V _X , V _Y ) expressed by the following equations with respect to a rotating magnetic field as expressed by Equation (8). Here, A _x and A _y are amplitude values of each signal, θ is a rotation angle of the rotating magnet, α is a non-orthogonality error between signals, and V _{os_x} and V _{os_y} are offsets of each signal.
(Equation 9)
V _X (θ) = A _x · cos (θ) + V _os — _x
V _Y (θ) = A _y · sin (θ + α) + V _{os_y}

Using the Hall electromotive force signals (V _X , V _Y ) as described above, an angle signal φ (θ) corresponding to the rotation angle θ of the rotating magnet can be calculated by the following equation as an example.
(Equation 10)
φ (θ) = tan ⁻¹ {V _Y (θ) / V _X (θ)}

  Here, it has been described that the rotation angle sensor 100 detects a magnetic field in a plane parallel to the XY plane, but a change in a magnetic field in another plane may be detected. The rotation angle sensor 100 can also detect a magnetic field in the Z-axis direction. For example, the rotation angle sensor 100 detects a magnetic field generated by rotation of a rotating magnet whose rotation axis is parallel to the Y-axis in a plane parallel to the XZ plane. A Hall electromotive force signal corresponding to the angle θ can be output. Similarly, the rotation angle sensor 100 detects a magnetic field generated by rotation of a rotating magnet whose rotation axis is parallel to the X axis in a plane parallel to the YZ plane, and outputs a Hall electromotive force signal corresponding to the rotation angle θ. You can also.

  Further, since the rotation angle sensor 100 can detect a three-dimensional magnetic field of the XYZ axes, it detects a magnetic field due to rotation in a plane that can be expressed by the XYZ axes, and outputs a Hall electromotive force signal corresponding to the rotation angle θ. can do. An example in which the rotation angle sensor 100 according to the present embodiment outputs a Hall electromotive force signal expressed by Equation (9) will be described.

  FIG. 3 shows an example of the rotation angle sensor 100 together with a schematic configuration of a circuit inside the rotation angle sensor 100. The rotation angle sensor 100 includes a first Hall element pair 110, a second Hall element pair 120, an X-axis signal output unit 140, a Y-axis signal output unit 150, and an angle signal calculation unit 160. The first Hall element pair 110 and the second Hall element pair 120 are substantially the same as the Hall element pair described in FIG. 1 and FIG. The X-axis signal output unit 140, the Y-axis signal output unit 150, and the angle signal calculation unit 160 may be formed inside the substrate 10 described with reference to FIG.

The X-axis signal output unit 140 magnetoelectrically converts the magnetic field in the X-axis direction and outputs a magnetic field detection signal in the X-axis direction. The X-axis signal output unit 140 includes an amplification unit 142 and an AD conversion unit 144. The amplification unit 142 is connected to the first Hall element pair 110 and amplifies the received Hall electromotive force signal with a predetermined amplification degree. The amplification unit 142 supplies the amplified Hall electromotive force signal to the AD conversion unit 144. The AD converter 144 is connected to the amplifier 142 and converts the received Hall electromotive force signal into a digital signal. AD conversion unit 144, supplies the angle signal calculation section 160 the converted digital signal _{V X} as a magnetic field detection signal.

The Y-axis signal output unit 150 magnetoelectrically converts a magnetic field in the Y-axis direction and outputs a magnetic field detection signal in the Y-axis direction. The Y-axis signal output unit 150 includes an amplification unit 152 and an AD conversion unit 154. The amplifying unit 152 is connected to the second Hall element pair 120 and amplifies the received Hall electromotive force signal with a predetermined amplification degree. The amplification unit 152 supplies the amplified Hall electromotive force signal to the AD conversion unit 154. The AD conversion unit 154 is connected to the amplification unit 152 and converts the received Hall electromotive force signal into a digital signal. The AD conversion unit 154 supplies the converted digital signal V _y to the angle signal calculation unit 160 as a magnetic field detection signal.

  The angle signal calculation unit 160 calculates an angle signal based on the magnetic field detection signals in the X-axis direction and the Y-axis direction. The angle signal calculation unit 160 calculates the equation (10) or an equivalent equation and outputs the angle signal φ (θ). As an example, the angle signal calculation unit 160 may include a calculation circuit such as a CORDIC (COORDINATE ROTATION DIGITAL COMPUTER) circuit based on a trigonometric function calculation model. The CORDIC circuit executes a predetermined CORDIC algorithm to calculate the angle signal φ (θ).

In the equation (9), the angle signal calculation unit 160 is, for example, _ideal when V _{os_x} and V _{os_y} are substantially zero, A _x is substantially equal to A _y , and α is substantially zero. When a Hall electromotive force signal (V _X , V _Y ) is obtained, an angle signal φ (θ) that substantially matches the rotation angle θ of the rotating magnet is output. However, if at least one of the offsets V _os — _x , V _os — _y , the difference between amplitude values (A _x −A _y ), and the non-orthogonality error α is not substantially zero, the angle signal φ (θ) output by the angle signal calculation unit 160 ) Does not coincide with the rotation angle θ, and the difference between φ (θ) and θ (φ (θ) −θ) becomes an angle nonlinearity error of the rotation angle sensor 100. The angle nonlinearity error will be described with reference to FIGS.

FIG. 4 shows an example of the Hall electromotive force signal (V _X , V _Y ) having an offset V _{os_x} in the X-axis direction. The horizontal axis of FIG. 4 shows a Hall electromotive force signal V _X of the X-axis direction, the vertical axis represents the Hall electromotive force signal V _Y of the Y-axis direction. A signal indicated by a dotted line is an ideal Hall electromotive force signal, and has a substantially circular shape on the XY plane. A signal indicated by a solid line is a Hall electromotive force signal having an offset V _{os_x} in the X-axis direction, and a substantially circular shape is translated in the V _X direction by a distance corresponding to the offset V _{os_x} . Next, the amplitude of the Hall electromotive force signal (V _X , V _Y ) in the example shown in FIG. 4 will be described.

FIG. 5 shows an example of the amplitude of the Hall electromotive force signal (V _X , V _Y ) having an offset V _{os_x} in the X-axis direction. Here, the amplitude signal A is an amplitude value calculated by (A _x ² + A _y ² ) ^1/2 . In response to the rotation of the rotating magnet by 360 °, the rotation angle sensor 100 outputs a Hall electromotive force signal (V _X , V _Y ) having a period of 360 °. FIG. 5 shows the Hall electromotive force signals (V _X , V _Y ) in this case, where the horizontal axis is the angular position θ of the rotating magnet and the vertical axis is the amplitude.

In the case of an ideal Hall electromotive force signal, the amplitude A is constant. However, as the Hall electromotive force signal V _X indicated by the dotted line, one of the Hall electromotive force signal V _X may include an offset V _{Os_x,} the amplitude A will vary depending on θ as indicated by one-dot chain lines. As shown in the example of FIG. 5, the fluctuation is generated by the sum of a sine wave signal and a cosine wave signal having an offset, and thus the fluctuation is synchronized with a cosine wave signal having a period of 360 °, and the cosine wave signal having a period of 360 °. The correlation with is stronger.

FIG. 6 shows an example of the angular non-linearity error of the Hall electromotive force signal (V _X , V _Y ) having the offset V _{os_x} in the X-axis direction shown in FIGS. 4 and 5. The horizontal axis in FIG. 6 indicates the angular position θ of the rotating magnet, and the vertical axis indicates the angle nonlinearity error (φ−θ). For example, when the angle position θ is 0 °, the angle signal φ (0 °) calculated according to the Hall electromotive force signal (V _X = A + V _{os — x} , V _Y = 0) is also 0 °, and the angle nonlinearity error is 0 °. When the angle position θ is 90 °, the angle signal φ (90 °) calculated according to the Hall electromotive force signal (V _X = V _os — _x , V _Y = A) is smaller than 90 °, and the angle nonlinearity The error is a value smaller than 0 °.

When the angular position θ is 180 °, the angle signal φ (180 °) calculated according to the Hall electromotive force signal (V _X = −A + V _os — _x , V _Y = 0) is also 180 °, and the angle nonlinearity error Becomes 0 °. When the angular position θ is 270 °, the angle signal φ (270 °) calculated according to the Hall electromotive force signal (V _X = V _os — _x , V _Y = −A) is larger than 270 °, and the angle nonlinearity The sex error is a value greater than 0 °. Thus, the angle nonlinearity error fluctuates so as to indicate −sin (θ) with respect to the angle position θ.

FIG. 7 shows an example of the Hall electromotive force signal (V _X , V _Y ) having an offset V _{os_y} in the Y-axis direction. Similar to FIG. 4, the horizontal axis of FIG. 7 shows the Hall electromotive force signal V _X of the X-axis direction, the vertical axis represents the Hall electromotive force signal V _Y of the Y-axis direction. A signal indicated by a dotted line is an ideal Hall electromotive force signal, and has a substantially circular shape on the XY plane. A signal indicated by a solid line is a Hall electromotive force signal having an offset V _{os_y} in the Y-axis direction, and a substantially circular shape is translated in the V _Y direction by a distance corresponding to the offset V _{os_y} .

As described above, when the Hall electromotive force signal V _Y includes the offset V _{os_y} , the amplitude A varies according to θ, similarly to the amplitude A illustrated in FIG. Since the fluctuation is generated by the sum of the cosine wave signal and the sine wave signal having an offset, the fluctuation is synchronized with the sine wave signal having a period of 360 °, and the correlation with the sine wave signal having a period of 360 ° is strengthened. The angle nonlinearity error corresponding to the correlation will be described with reference to FIG.

FIG. 8 shows an example of the angular non-linearity error of the Hall electromotive force signal (V _X , V _Y ) having the offset V _{os_y} in the Y-axis direction shown in FIG. Similar to FIG. 6, the horizontal axis in FIG. 8 represents the angular position θ of the rotating magnet, and the vertical axis represents the angle nonlinearity error (φ−θ). For example, when the angle position θ is 0 °, the angle signal φ (0 °) calculated according to the Hall electromotive force signal (V _X = A, V _Y = V _os — _y ) is larger than 0 °, and the angle nonlinearity The error is greater than 0 °. When the angle position θ is 90 °, the angle signal φ (90 °) calculated according to the Hall electromotive force signal (V _X = 0, V _Y = A + V _os — _y ) is 90 °, and the angle nonlinearity error is 0 °.

When the angle position θ is 180 °, the angle signal φ (180 °) calculated according to the Hall electromotive force signal (V _X = −A, V _Y = V _os — _y ) is smaller than 180 °, and the angle nonlinearity The sex error is less than 0 °. When the angle position θ is 270 °, the angle signal φ (270 °) calculated according to the Hall electromotive force signal (V _X = 0, V _Y = −A + V _os — _y ) is 270 °, and the angle nonlinearity error Becomes 0 °. As described above, the angle nonlinearity error fluctuates so as to indicate cos (θ) with respect to the angle position θ.

FIG. 9 shows an example of the Hall electromotive force signal (V _X , V _Y ) having a magnetic sensitivity mismatch. Similar to FIG. 4, the horizontal axis of FIG. 9 represents the Hall electromotive force signal V _X in the X-axis direction, and the vertical axis represents the Hall electromotive force signal V _Y in the Y-axis direction. A signal indicated by a dotted line is an ideal Hall electromotive force signal, and has a substantially circular shape on the XY plane. A signal indicated by a solid line is a Hall electromotive force signal having a magnetic sensitivity mismatch (A _x −A _y ≠ 0), and shows an example of A _x <A _y . In this case, the Hall electromotive force signal (V _X , V _Y ) has an elliptical shape having a major axis in the Y-axis direction.

  Thus, when the Hall electromotive force signal has a magnetic sensitivity mismatch, the amplitude A varies according to θ. The fluctuation is generated by the sum of the cosine wave signal and the sine wave signal having a different amplitude value from the cosine wave signal. Become stronger. The angle nonlinearity error corresponding to the correlation will be described with reference to FIG.

FIG. 10 shows an example of the angle nonlinearity error of the Hall electromotive force signal (V _X , V _Y ) having a magnetic sensitivity mismatch shown in FIG. Similar to FIG. 6, the horizontal axis of FIG. 10 indicates the angular position θ of the rotating magnet, and the vertical axis indicates the angle nonlinearity error (φ−θ). For example, when the angle position θ is 0 °, the angle signal φ (0 °) calculated according to the Hall electromotive force signal (V _X = A _x , V _Y = 0) is 0 °, and the angle nonlinearity error is 0 °. Similarly, when the angular position θ is 90 °, 180 °, or 270 °, the angle signal φ (θ) calculated according to the Hall electromotive force signal is also 0 °, and the angle nonlinearity error is 0 °.

When the angular position θ is 45 °, the angle signal φ (() calculated according to the Hall electromotive force signal (V _X = A _x · 2 ^−1/2 , V _Y = A _y · 2 ^−1/2 ) 45 °) is greater than 45 ° (A _x <A _y ), and the angle nonlinearity error is greater than 0 °. When the angular position θ is 135 °, the angle signal φ calculated according to the Hall electromotive force signal (V _X = −A _x · 2 ^−1/2 , A _y · V _Y = 2 ^−1/2 ). (135 °) is smaller than 135 °, and the angle nonlinearity error is smaller than 0 °. Thus, the angle nonlinearity error fluctuates so as to indicate sin (2θ) with respect to the angle position θ.

FIG. 11 shows an example of the Hall electromotive force signal (V _X , V _Y ) having a non-orthogonal error α. Similar to FIG. 4, the horizontal axis of FIG. 11 represents the Hall electromotive force signal V _X in the X-axis direction, and the vertical axis represents the Hall electromotive force signal V _Y in the Y-axis direction. A signal indicated by a dotted line is an ideal Hall electromotive force signal, and has a substantially circular shape on the XY plane. A signal indicated by a solid line is a Hall electromotive force signal having a non-orthogonality error α, and an example in which α> 0 is shown. In this case, the Hall electromotive force signal (V _X , V _Y ) has an elliptical shape having a major axis.

  Thus, when the Hall electromotive force signal has a non-orthogonal error α, the amplitude A varies according to θ. The fluctuation is caused by the sum of the cosine wave signal and a sine wave signal having a phase different from that of the cosine wave signal. Therefore, the fluctuation is synchronized with the cosine wave signal having a period of 180 ° and has a strong correlation with the double angle cosine wave signal. Become.

FIG. 12 shows an example of the angular nonlinearity error of the Hall electromotive force signal (V _X , V _Y ) having the non-orthogonal error α shown in FIG. Similar to FIG. 6, the horizontal axis of FIG. 12 indicates the angular position θ of the rotating magnet, and the vertical axis indicates the angle nonlinearity error (φ−θ). When the Hall electromotive force signal has a non-orthogonal error α, as shown in FIG. 12, it fluctuates so as to indicate cos (2θ) with respect to the angular position θ.

As described above, the rotation angle sensor 100 has −sin (θ) for the offset V _{os_x in} the X-axis direction, cos (θ) for the offset V _{os_y in the} Y-axis direction, and the magnetic sensitivity mismatch. Sin (2θ) and cos (2θ) with respect to the non-orthogonality error α, respectively, the angular nonlinearity error varies according to the angular position θ. Therefore, the rotation angle sensor 100 of the present embodiment is calibrated to reduce the angle nonlinearity error by using a calibration parameter for calibrating the angle nonlinearity error. Here, the calibration parameter is generated by a calibration parameter generation device or the like based on the correlation between the output of the rotation angle sensor 100 and a predetermined periodic function.

  FIG. 13 shows an example of the rotation angle sensor 100 according to this embodiment together with the calibration parameter generation device 200. The rotation angle sensor 100 includes a first Hall element pair 110, a second Hall element pair 120, an X-axis signal output unit 140, a Y-axis signal output unit 150, an angle signal calculation unit 160, and an input / output unit 170. A storage unit 180 and an error correction unit 190. The first Hall element pair 110 and the second Hall element pair 120 are substantially the same as the Hall element pair described in FIG. 1 and FIG. The X-axis signal output unit 140, the Y-axis signal output unit 150, the angle signal calculation unit 160, the input / output unit 170, the storage unit 180, and the error correction unit 190 may be formed inside the substrate 10 described with reference to FIG. .

The X-axis signal output unit 140 magnetoelectrically converts the magnetic field in the X-axis direction and outputs a magnetic field detection signal in the X-axis direction. The X-axis signal output unit 140 includes an amplification unit 142 and an AD conversion unit 144. The amplification unit 142 is connected to the first Hall element pair 110 and amplifies the received Hall electromotive force signal with a predetermined amplification degree. The amplification unit 142 supplies the amplified Hall electromotive force signal to the AD conversion unit 144. The AD converter 144 is connected to the amplifier 142 and converts the received Hall electromotive force signal into a digital signal. AD conversion unit 144 supplies the error correction unit 190 the converted digital signal _{V X} as a magnetic field detection signal.

The Y-axis signal output unit 150 magnetoelectrically converts a magnetic field in the Y-axis direction and outputs a magnetic field detection signal in the Y-axis direction. The Y-axis signal output unit 150 includes an amplification unit 152 and an AD conversion unit 154. The amplifying unit 152 is connected to the second Hall element pair 120 and amplifies the received Hall electromotive force signal with a predetermined amplification degree. The amplification unit 152 supplies the amplified Hall electromotive force signal to the AD conversion unit 154. The AD conversion unit 154 is connected to the amplification unit 152 and converts the received Hall electromotive force signal into a digital signal. AD conversion unit 154 supplies the error correction unit 190 the converted digital signal _{V X} as a magnetic field detection signal.

  The angle signal calculation unit 160 calculates the angle signal φ (θ) based on the magnetic field detection signals in the X-axis direction and the Y-axis direction. The angle signal calculation unit 160 calculates the equation (10) or an equivalent equation and outputs the angle signal φ (θ). As an example, the angle signal calculation unit 160 may include a calculation circuit such as a CORDIC circuit based on a trigonometric function calculation model. The CORDIC circuit executes a predetermined CORDIC algorithm to calculate the angle signal φ (θ).

In the equation (9), the angle signal calculation unit 160 is, for example, _ideal when V _{os_x} and V _{os_y} are substantially zero, A _x is substantially equal to A _y , and α is substantially zero. When a Hall electromotive force signal (V _X , V _Y ) is obtained, an angle signal φ (θ) that substantially matches the rotation angle θ of the rotating magnet is output. In addition, when the Hall electromotive force signal (V _X , V _Y ) is corrected to an ideal signal, the angle signal calculation unit 160 outputs an angle signal φ (θ) that substantially matches the rotation angle θ of the rotating magnet. To do.

  The input / output unit 170 is connected to an external device or the like, and exchanges calibration parameters with the external device or the like. The input / output unit 170 may be an interface circuit of the rotation angle sensor 100. In this case, in addition to the calibration parameters, other parameters and data used inside the rotation angle sensor 100 may be exchanged. The input / output unit 170 supplies calibration parameters received from the outside to the storage unit 180. Further, the input / output unit 170 supplies the calibration parameters stored in the storage unit 180 to the outside.

The storage unit 180 stores calibration parameters. At least one calibration parameter for calibrating the error of the angle signal calculated by the rotation angle sensor 100 is stored. The storage unit 180 has an error parameter that reduces an error proportional to at least one of the sine of the angle signal, the cosine of the angle signal, the sine of twice the angle signal, and the cosine of twice the angle signal. May be stored as calibration parameters. The storage unit 180 may store an error parameter and a calibration parameter. Calibration parameters, the offset V _{Os_x} the X-axis _{direction, Y} axis direction of the offset V _{Os_y,} mismatch of the magnetic sensitivity, and among the angular nonlinear error based on non-orthogonality errors alpha, is a parameter for reducing at least one error .

  The error correction unit 190 corrects errors in the magnetic field detection signals in the X-axis direction and the Y-axis direction based on the calibration parameters, and outputs error correction signals in the X-axis direction and the Y-axis direction, respectively. The error correction unit 190 is connected to the X-axis signal output unit 140 and the Y-axis signal output unit 150 and receives a magnetic field detection signal. The error correction unit 190 is connected to the storage unit 180 and corrects the received magnetic field detection signal using the calibration parameters read from the storage unit 180. The error correction unit 190 supplies the corrected magnetic field detection signal to the angle signal calculation unit 160 as an error correction signal.

  Thereby, the angle signal calculation unit 160 receives the error correction signal supplied from the error correction unit 190 as a magnetic field detection signal, and outputs the angle signal φ (θ). That is, the angle signal calculation unit 160 calculates a corrected angle signal based on the error correction signals in the X-axis direction and the Y-axis direction. Here, when the error correction signal is an appropriately corrected signal, the angle signal calculation unit 160 outputs an angle signal φ (θ) that substantially matches the rotation angle θ.

  The rotation angle sensor 100 according to the present embodiment described above corrects the angle signal using the calibration parameter generated by the calibration parameter generation device 200 connected to the input / output unit 170. The calibration parameter generation device 200 of the present embodiment includes an acquisition unit 210, a calculation unit 220, and a parameter supply unit 230.

  The acquisition unit 210 acquires the output signal of the rotation angle sensor 100. The acquisition unit 210 in FIG. 13 will describe an example in which the magnetic field detection signals output from the X-axis signal output unit 140 and the Y-axis signal output unit 150 are acquired as output signals. In this case, the acquisition unit 210 may be connected to the X-axis signal output unit 140 and the Y-axis signal output unit 150 to acquire a magnetic field detection signal. When the angle signal calculation unit 160 outputs a magnetic field detection signal, the acquisition unit 210 may be connected to the angle signal calculation unit 160 and acquire the magnetic field detection signal. The acquisition unit 210 may store the acquired magnetic field detection signal in a storage unit or the like inside the calibration parameter generation device 200.

The calculation unit 220 calculates calibration parameters for calibrating the rotation angle sensor 100 based on the output signal. The calculation unit 220 receives a magnetic field detection signal, which is an output signal, from the acquisition unit 210 or the storage unit in the calibration parameter generation device 200, and the X-axis direction offset V _{os_x} , the Y-axis direction offset V _{os_y} , and the magnetic sensitivity mismatch. , And a calibration parameter that reduces at least one of the non-linearity errors based on the non-orthogonality error α. The generation of the calibration parameter will be described later.

  The parameter supply unit 230 supplies calibration parameters to the storage unit 180 of the rotation angle sensor 100 for storage. The parameter supply unit 230 is connected to the calculation unit 220 and receives calibration parameters from the calculation unit 220. The parameter supply unit 230 is connected to the input / output unit 170 of the rotation angle sensor 100, supplies calibration parameters to the storage unit 180 via the input / output unit 170, and causes the storage unit 180 to store the calibration parameters.

  In addition, when the calibration parameter is stored in the storage unit 180, the parameter supply unit 230 calibrates the calibration parameter when the calibration parameter creation date and time received from the calculation unit 220 is newer than the stored calibration parameter creation date and time. May be updated. Instead, the parameter supply unit 230 may linearly combine a plurality of calibration parameters and store them in the storage unit 180 as new calibration parameters.

  The calibration parameter generation device 200 of the present embodiment described above generates a calibration parameter based on the magnetic field detection signal acquired from the rotation angle sensor 100. The generation of calibration parameters of the calibration parameter generation apparatus 200 will be described with reference to FIG.

  FIG. 14 shows a first operation flow of the calibration parameter generation apparatus 200 according to the present embodiment. The calibration parameter generation device 200 executes the first operation flow shown in FIG. 14, acquires the magnetic field detection signal from the rotation angle sensor 100, and sets the calibration parameter for correcting the magnetic field detection detection signal of the rotation angle sensor 100. Generate.

  First, the rotation angle sensor 100 is installed on the XY plane (S300). Here, the XY plane on which the rotation angle sensor 100 is installed is a plane substantially parallel to the direction of the magnetic field detected by the rotation angle sensor 100. Further, it is desirable that the plane is substantially coincident with the plane formed by the direction of the magnetic field detected by the rotation angle sensor 100.

  Next, a magnetic field is applied to the rotation angle sensor 100, and the calibration parameter generation apparatus 200 acquires an output signal of the rotation angle sensor 100 (S310). Here, the magnetic field applied to the rotation angle sensor 100 is a magnetic field in the N direction (N is an integer of 3 or more) whose direction is different by an angle obtained by equally dividing 360 degrees into N on the XY plane. For example, the rotation angle sensor 100 is applied with magnetic fields in three directions on the XY plane having angles of 0 °, 120 °, and 240 ° with respect to predetermined directions on the XY plane. An example of an apparatus for applying such a magnetic field will be described with reference to FIG.

  FIG. 15 shows the magnetic field application device 30 according to the present embodiment together with the rotation angle sensor 100 and the calibration parameter generation device 200. FIG. 15 shows an example in which the magnetic field application apparatus 30 applies to the rotation angle sensor 100 magnetic fields in four directions whose directions are different by an angle (90 °) obtained by dividing 360 degrees into four equal parts. The magnetic field application device 30 includes a first coil unit 42, a second coil unit 44, a third coil unit 46, and a fourth coil unit 48.

  The first coil portion 42 and the third coil portion 46 may be Helmholtz coils formed of substantially the same shape and material and having substantially the same central axis. FIG. 15 shows an example in which the central axes of the first coil portion 42 and the third coil portion 46 are arranged substantially parallel to the Y-axis direction. The first coil unit 42 and the third coil unit 46 switch and apply magnetic fields in the + Y axis direction and the −Y axis direction to the rotation angle sensor 100 according to the direction of the flowing current. The first coil portion 42 and the third coil portion 46 can adjust the magnitude of the magnetic field to be applied by controlling the magnitude of the flowing current. That is, the first coil unit 42 and the third coil unit 46 apply a magnetic field having angles of about 90 ° and about 270 ° to the rotation angle sensor 100 with respect to the + X axis direction.

  The second coil portion 44 and the fourth coil portion 48 may be Helmholtz coils formed of substantially the same shape and material and having substantially the same central axis. FIG. 15 shows an example in which the central axes of the second coil portion 44 and the fourth coil portion 48 are arranged substantially parallel to the X-axis direction. The second coil unit 44 and the fourth coil unit 48 switch and apply magnetic fields in the + X axis direction and the −X axis direction to the rotation angle sensor 100 according to the direction of the flowing current. That is, the second coil portion 44 and the fourth coil portion 48 apply a magnetic field having angles of approximately 0 ° and approximately 180 ° to the rotation angle sensor 100 with respect to the + X axis direction.

  FIG. 15 shows an example in which the rotation angle sensor 100 is arranged at the intersection of the central axes of the first coil portion 42 and the third coil portion 46 and the central axes of the second coil portion 44 and the fourth coil portion 48. Show. As described above, the magnetic field application device 30 has a magnetic field in the N direction (N is an integer of 3 or more) having different directions by an angle obtained by equally dividing 360 degrees into N on the XY plane according to the arrangement of the plurality of coil units. Can be applied to the rotation angle sensor 100, respectively.

  FIG. 16 shows a first example of a magnetic field applied to the rotation angle sensor 100 by the magnetic field application device 30 according to the present embodiment. FIG. 16 shows an example in which the magnetic field application device 30 has three Helmholtz coils and applies three magnetic field vectors in different directions at equal intervals of 120 ° to the rotation angle sensor 100. Here, each magnetic field vector may have an offset of a predetermined angle with respect to the + X axis direction. FIG. 16 shows an example in which the offset is δ. That is, FIG. 16 is an example in which the magnetic field application device 30 applies magnetic field vectors in three directions of angles δ, δ + 120 °, and δ + 240 ° to the rotation angle sensor 100 in the XY plane.

  FIG. 17 shows a second example of the magnetic field applied to the rotation angle sensor 100 by the magnetic field application device 30 according to this embodiment. FIG. 17 shows an example in which the magnetic field application device 30 has two Helmholtz coils and applies four magnetic field vectors in different directions at equal intervals of 90 ° to the rotation angle sensor 100 as in FIG. 15. Here, each magnetic field vector may have an offset δ of a predetermined angle with the + X-axis direction. FIG. 17 shows an example in which the magnetic field application device 30 applies magnetic field vectors in four directions of angles δ, δ + 90 °, δ + 180 °, and δ + 270 ° to the rotation angle sensor 100 in the XY plane.

As described above, the magnetic field application device 30 applies the N-direction magnetic field having the angle θ _n with respect to the + X-axis direction to the rotation angle sensor 100 as shown in the following equation in order to calibrate the rotation angle sensor 100.

In this way, the acquisition unit 210 applies each of the magnetic fields in the N direction (N is an integer of 3 or more) having different directions by an angle obtained by equally dividing 360 degrees into N on the XY plane. The output signal output in response is acquired from the rotation angle sensor 100. That is, the acquisition unit 210 of the present embodiment corresponds to each angle θ _n (n = 0, 1, 2,..., N−1) of the magnetic field in the N direction with respect to a predetermined direction on the XY plane. The magnetic field detection signals (V _X (θ _n ), V _Y (θ _n )) in the X-axis direction and Y-axis direction of the rotation angle sensor 100 that are output in this manner are acquired.

Next, the calculation unit 220 calculates calibration parameters for calibrating the rotation angle sensor based on the magnetic field detection signals (V _X (θ _n ), V _Y (θ _n )) (S320). The calculation unit 220 calculates a calibration parameter based on the correlation between the magnetic field detection signals in the X-axis direction and the Y-axis direction and a predetermined periodic function into which the angle θ _n is substituted. As described with reference to FIGS. 4 to 12, the rotation angle sensor 100 has an angular nonlinearity error that has a strong correlation with a predetermined periodic function. Therefore, the calculation unit 220 uses the periodic function to generate a magnetic field detection signal and Thus, an error parameter corresponding to the angle nonlinearity error is calculated.

More specifically, the calculation unit 220, as in the correlation function represented by the following expression, each of the magnetic field detection signals (V _X (θ _n ), V _Y (θ _n )), a sine wave function, and a cosine wave function Correlate with each.

As shown by the equation (12), the calculation unit 220 calculates the sum of multiplications of N periodic functions obtained by changing 360 degrees by N equally divided angles as a correlation function, so that most terms cancel each other. As a result, the number of terms is 1 for all the calculation results. Then, the calculation unit 220 can calculate a magnetic sensitivity mismatch (A _x −A _y ) by calculating the following equation.

Similarly, the calculation unit 220, by calculating the following equation, non-orthogonality errors alpha, it is possible to calculate the offset _{V Os_x} the X-axis direction, and the offset _{V Os_y} the Y-axis direction.

As described above, the calculation unit 220 generates an error based on the magnetic field detection signals (V _X (θ _n ), V _Y (θ _n )) output from the rotation angle sensor 100 in accordance with the magnetic field applied by the magnetic field application device 30. Parameters (V _os — _x , V _os — _y , A _x −A _y , α) can be calculated. Then, the calculation unit 220 calculates a calibration parameter for canceling the error parameter.

For example, the calculation unit 220 uses −V _{os_x} as a first parameter for calibrating the offset of the magnetic field detection signal in the X-axis direction, and −V _{os_y} as a second parameter for calibrating the offset of the magnetic field detection signal in the Y-axis direction. , Respectively. Thereby, the rotation angle sensor 100 corrects the offset of the magnetic field detection signals (V _X (θ _n ), V _Y (θ _n )) using the first parameter and the second parameter as in the following equation. Can do.

The calculation unit 220 may calculate (A _x / A _y ) as a third parameter for calibrating the sensitivity mismatch of the magnetic field detection signals in the X-axis direction and the Y-axis direction. Accordingly, the rotation angle sensor 100 can correct the sensitivity mismatch of the magnetic field detection signals (V _X (θ _n ), V _Y (θ _n )) using the third parameter as in the following equation.

Further, the calculation unit 220 may calculate −tan (α) as a fourth parameter for calibrating non-orthogonality errors of the magnetic field detection signals in the X-axis direction and the Y-axis direction. Thereby, the rotation angle sensor 100 can correct the non-orthogonality error of the magnetic field detection signals (V _X (θ _n ), V _Y (θ _n )) using the fourth parameter as in the following equation. it can. As above. The calculation unit 220 calculates a calibration parameter including at least one of the four parameters from the first parameter to the fourth parameter.

  Next, the parameter supply unit 230 supplies the calibration parameters calculated by the calculation unit 220 to the storage unit 180 of the rotation angle sensor 100 for storage (S330). As described above, the calibration parameter generation apparatus 200 according to the present embodiment applies a magnetic field in a plurality of predetermined directions to the rotation angle sensor 100 using the magnetic field application apparatus 30 and corresponds to the generated angle nonlinearity error. Using the correlation function, a calibration parameter that corrects the angle nonlinearity error of the rotation angle sensor 100 can be generated.

Thereby, the rotation angle sensor 100 can correct | amend an angle nonlinearity error using the said calibration parameter. That is, the error correction unit 190 uses the calibration parameters for the magnetic field detection signals (V _X , V _Y ) supplied from the X-axis signal output unit 140 and the Y-axis signal output unit 150 from (Equation 16). The calculation of equation (18) is executed and an error correction signal (V _X ', V _Y ') is output. Then, the angle signal calculation unit 160 calculates the angle signal using the error correction signals (V _X ′, V _Y ′) (that is, the corrected magnetic field detection signal) in the X-axis direction and the Y-axis direction. An accuracy signal with reduced angular nonlinearity error can be output.

  FIG. 18 shows a modification of the rotation angle sensor 100 according to the present embodiment, together with a corresponding calibration parameter generation device 200. In the rotation angle sensor 100 of the present modification, the same reference numerals are given to the substantially same operations as those of the rotation angle sensor 100 according to the present embodiment shown in FIG. 13, and the description thereof is omitted. The rotation angle sensor 100 of the present modification corrects the angle signal φ (θ) using the calibration parameter calculated based on the angle signal φ (θ) calculated by the angle signal calculation unit 160.

That is, the angle signal calculation unit 160 of the present modification calculates the angle signal φ (θ) based on the magnetic field detection signals (V _X , V _Y ) in the X axis direction and the Y axis direction. Then, the error correction unit 190 corrects the error of the angle signal φ (θ) based on the calibration parameter, thereby reducing the angle nonlinearity error (φ (θ) −θ) of the rotation angle sensor 100. Here, the angle nonlinearity error (φ (θ) −θ) fluctuates so as to show a predetermined periodic function as described with reference to FIGS. it can.

Here, the four coefficients A to D are error parameters (A, B, C, D) whose values are determined according to the magnitudes of the corresponding angular nonlinear errors. For example, when the angle non-linearity error due to the offset V _{os_x} in the X-axis direction is larger than other angle non-linearity errors, the coefficient A is larger than the other coefficients B to D. When the angle signal φ (θ) output from the rotation angle sensor 100 is an ideal output that is substantially the same as the angular position θ, the error parameters (A, B, C, D) are all substantially zero.

  The calibration parameter generation device 200 corresponding to the rotation angle sensor 100 of the present modification acquires the angle signal φ (θ) output from the angle signal calculation unit 160 as an output signal of the rotation angle sensor 100. That is, the acquisition unit 210 is connected to the angle signal calculation unit 160 and acquires the angle signal φ (θ). Instead, the acquisition unit 210 may be connected to the error correction unit 190 and acquire the angle signal φ (θ).

The calibration parameter generation device 200 performs the rotation when the magnetic field application device 30 applies magnetic fields in N directions (N is an integer of 3 or more) having different directions by 360 degrees to the rotation angle sensor 100. An output signal of the angle sensor 100 (an angle signal in the case of this modification) is acquired. That is, the acquisition unit 210 outputs the rotation corresponding to each angle θ _n (n = 0, 1,..., N−1) of the magnetic field in the N direction with respect to a predetermined direction on the XY plane. N angle signals φ (θ _n ) of the angle sensor 100 are acquired.

Then, the calculation unit 220 calculates calibration parameters based on error parameters (A, B, C, D) obtained by substituting the angle θ _n and the angle signal φ (θ _n ) into a predetermined periodic function. . More specifically, the calculation unit 220 calculates each difference (φ (θ _n ) −θ _n ) between the angle signal φ (θ _n ) and the angular position θ _n of the applied magnetic field, as in the correlation function represented by the following equation. And the correlation between the sine wave function and the cosine wave function are calculated, and error parameters (A, B, C, D) are obtained.

Then, the calculation unit 220 calculates a calibration parameter for canceling the error parameter from each of the angle signals φ (θ _n ). For example, the calculation unit 220 uses -A as a first parameter for calibrating the offset of the magnetic field detection signal in the X-axis direction, and -B as a second parameter for calibrating the offset of the magnetic field detection signal in the Y-axis direction. calculate. Similarly, the calculation unit 220 sets -C as a third parameter for calibrating the sensitivity mismatch of the magnetic field detection signals in the X-axis direction and the Y-axis direction, and non-orthogonal values of the magnetic field detection signals in the X-axis direction and the Y-axis direction. -D may be calculated as a fourth parameter for calibrating the sex error.

As described above, the calculation unit 220 calculates calibration parameters including at least one of the four parameters from the first parameter to the fourth parameter. The parameter supply unit 230 supplies the calibration parameters calculated by the calculation unit 220 to the storage unit 180 of the rotation angle sensor 100 for storage. Thereby, the rotation angle sensor 100 can correct the non-orthogonality error of the angle signal φ (θ _n ) using the first parameter to the fourth parameter as in the following equation.

  Here, the rotation angle sensor 100 may store a plurality of types of calibration parameters in the storage unit 180 to reduce angular nonlinearity errors based on a plurality of types of factors. For example, the storage unit 180 of the rotation angle sensor 100 is proportional to at least two of the sine of the angle signal, the cosine of the angle signal, the sine of twice the angle signal, and the cosine of twice the angle signal. The error parameter that reduces the error is stored as a calibration parameter. The error correction unit 190 linearly combines error parameters corresponding to at least two of the sine of the angle signal, the cosine of the angle signal, the sine of twice the angle signal, and the cosine of twice the angle signal. Then, the angle signal may be corrected by subtracting the linearly combined value from the angle signal.

  As described above, the rotation angle sensor 100 according to the present modification can output an angle signal in which the angle nonlinearity error is reduced by using the calibration parameter generated by the corresponding calibration parameter generation device 200. That is, the calibration parameter generation apparatus 200 can generate a calibration parameter that reduces the angle nonlinearity error of the rotation angle sensor 100 using the magnetic field application apparatus 30 and can calibrate the rotation angle sensor 100.

  FIG. 19 shows an example of the rotation angle sensor module 300 according to this embodiment together with the calibration parameter generation device 200. The rotation angle sensor module 300 includes the rotation angle sensor 100, a rotating magnet 410, a rotating shaft 412, and a motor 420. Since the rotation angle sensor 100 has been described with reference to FIGS. 1 to 18, the schematic configuration and calibration are omitted here.

  The rotating magnet 410 rotates around the rotating shaft 412. FIG. 19 shows an example in which the rotating magnet 410 is provided above the rotation angle sensor 100. For example, the rotating magnet 410 has a disk shape and rotates on a plane substantially parallel to the XY plane. The rotating magnet 410 may be divided into two regions each having a semicircular cross section substantially parallel to the XY plane, and forms a magnet in which one region is an S pole and the other region is an N pole. The rotating magnet 410 causes the rotating angle sensor 100 to generate a rotating magnetic field represented by, for example, the equation (8) by rotating on a plane substantially parallel to the XY plane.

  The rotation shaft 412 is formed in a direction substantially perpendicular to the XY plane. As an example, the rotation axis 412 has an intersection of the X axis passing through the first Hall element pair 110 and the Y axis passing through the second Hall element pair 120 on the extension line of the central axis on the rotation angle sensor 100 side. Formed. The rotating shaft 412 has one end connected to the rotating magnet 410 and the other end connected to the motor 420. The motor 420 rotates the rotating shaft 412 and the rotating magnet 410 connected to the rotating shaft.

  The rotation angle sensor module 300 is formed by assembling a calibrated rotation angle sensor 100 and a rotating magnet 410 that rotates about the rotation axis 412. That is, the rotation angle sensor 100 detects the magnetic field in the X-axis direction and the magnetic field in the Y-axis direction on the XY plane, and detects the rotation angle on the XY plane of the rotating magnet 410 that rotates about the rotation axis 412.

  The rotation angle sensor 100 can be calibrated as shown in FIG. 14 before being assembled as the rotation angle sensor module 300. However, if an assembly error occurs in the process of assembling the rotation angle sensor module 300, the rotation angle sensor 100 generates an angle nonlinearity error due to the assembly error. 20 to 22 show examples of such assembly errors.

  FIG. 20 shows an example of an assembly error in which the center axis shift occurs in the rotation angle sensor module 300 according to the present embodiment. FIG. 21 shows an example of an assembly error in which eccentricity occurs in the rotation angle sensor module 300 according to this embodiment. FIG. 22 shows an example of an assembly error in which the rotation magnet 410 is inclined in the rotation angle sensor module 300 according to the present embodiment.

  Even when such an error occurs, the rotation angle sensor 100 generates an angular non-linearity error that varies so as to indicate a periodic function according to the angular position θ of the rotating magnet 410, as will be described later. Therefore, the calibration parameter generation apparatus 200 according to the present embodiment calibrates the angle nonlinearity error caused by the assembly error of the rotation angle sensor module 300 as in the case of generating the calibration parameter for calibrating the rotation angle sensor 100. Is generated.

  FIG. 23 shows a second operation flow of the calibration parameter generation device 200 according to the present embodiment. The calibration parameter generation device 200 executes the second operation flow shown in FIG. 23, acquires an output signal from the rotation angle sensor 100, and generates a calibration parameter for correcting the output signal of the rotation angle sensor module 300.

  First, the rotation angle sensor module 300 is installed to operate (S500). For example, the rotation angle sensor module 300 is installed on a plane substantially parallel to the XY plane. Here, the installation of the rotation angle sensor module 300 is, for example, assembling the module by combining the rotation angle sensor 100, the rotating magnet 410, the rotating shaft 412, and the motor 420. Thereby, the rotation angle sensor 100 is installed on the XY plane.

  Next, the rotation magnet 410 is rotated to a predetermined rotation angle, and the output of the rotation angle sensor 100 when a magnetic field in a plurality of directions is applied to the rotation angle sensor 100 is acquired (S510). That is, the rotating magnet 410 is rotated by an angle equal to 360 degrees divided by N, and magnetic fields in N directions (N is an integer of 3 or more) having different directions are applied to the rotation angle sensor 100, respectively. The predetermined rotation angle of the rotating magnet 410 may ideally be an angle that generates the same magnetic field as the plurality of magnetic fields applied to the rotation angle sensor 100 by the magnetic field application device 30 described in FIG.

  FIG. 24 shows a first example of the rotational position of the rotating magnet 410 in the rotational angle sensor module 300 of the present embodiment. FIG. 24 shows an example in which the motor 420 rotates the rotating magnet 410 by 90 ° and applies four magnetic field vectors corresponding to the four rotating positions of the rotating magnet 410 to the rotation angle sensor 100. Here, an example in which the rotational position of each rotary magnet 410 has an offset of a predetermined angle δ with respect to the + X axis direction is shown. When the rotation angle sensor module 300 is ideally assembled, when the rotation magnet 410 is positioned as shown in FIG. 24, the rotation magnet 410 has an angle δ, δ + 90 °, δ + 180 ° with respect to the + X axis direction in the XY plane. And magnetic field vectors in four directions of δ + 270 ° can be applied to the rotation angle sensor 100.

  However, when an assembly error occurs in the rotation angle sensor module 300, a magnetic field is directed to the rotation angle sensor 100 in a direction different from a predetermined direction. That is, FIG. 24 shows that when the rotating magnet 410 is at four rotational positions of angles δ, δ + 90 °, δ + 180 °, and δ + 270 ° with respect to the + X-axis direction, An example in which a magnetic field vector is applied to the rotation angle sensor 100 is shown.

  FIG. 25 shows a second example of the rotational position of the rotating magnet 410 in the rotational angle sensor module of the present embodiment. FIG. 25 shows an example in which the motor 420 rotates the rotating magnet 410 by 45 ° and applies eight magnetic field vectors corresponding to the eight rotating positions of the rotating magnet 410 to the rotation angle sensor 100. Here, an example in which the rotational position of each rotary magnet 410 has an offset of a predetermined angle δ with respect to the + X axis direction is shown. That is, FIG. 25 shows that each of the rotating magnets 410 has eight rotating positions at an angle δ + n · 45 ° (n = 0, 1, 2,..., 7) with respect to the + X-axis direction. An example is shown in which eight magnetic field vectors corresponding to the rotational positions are applied to the rotation angle sensor 100.

The acquisition unit 210 acquires, from the rotation angle sensor 100, an output signal that is output in response to application of a magnetic field in the N direction. The acquisition unit 210 is input to the rotation angle sensor 100 at each rotation position of a predetermined angle θ _n (n = 0, 1,..., N−1) of the rotary magnet 410 on the XY plane. N magnetic field detection signals (V _X (θ _n ), V _Y (θ _n )) of the rotation angle sensor 100 output corresponding to the magnetic field may be acquired, and instead of this, the angle signal φ (θ _n ) may be obtained. An example in which the acquisition unit 210 according to the present embodiment acquires N magnetic field detection signals (V _X (θ _n ), V _Y (θ _n )) will be described. That is, in this case, the schematic configuration of the rotation angle sensor 100 is substantially the same as the schematic configuration shown in FIG.

Next, the calculation unit 220 calculates calibration parameters for calibrating the rotation angle sensor 100 based on the output signal of the rotation angle sensor 100 (S520). Similar to the calibration of the rotation angle sensor 100, the calculation unit 220 calculates the correlation between the magnetic field detection signals in the X-axis direction and the Y-axis direction and a predetermined periodic function into which the angle θ _n that is the rotation position of the magnet is substituted. Based on this, a calibration parameter is calculated. That is, the calculation unit 220 calculates the error parameters (V _os — _x , V _os — _y , A _x −A _y , α) and the calibration parameters using the equations (12) to (18).

  Since the rotation angle sensor 100 generates an angular non-linearity error that varies so as to indicate a periodic function according to the angular position θ of the rotating magnet 410, the calculation unit 220 uses the mathematical formula used to calibrate the rotation angle sensor 100. Thus, the calibration parameter can be calculated. Here, the generation of the angle nonlinearity error of the rotation angle sensor 100 will be described with reference to FIGS. 26 and 27. FIG.

  FIG. 26 shows an example in which magnetic fields in eight directions are applied to the rotation angle sensor 100 of the ideal rotation angle sensor module 300, respectively. That is, FIG. 26 shows, by arrows, the directions of magnetic fields generated on the XY plane where the rotation angle sensor 100 is installed when the rotating magnet 410 rotates at 45 ° intervals. A plurality of circles in FIG. 26 respectively indicate the rotating magnets 410, and squares indicated by dotted lines in the circles indicate the positions of the rotation angle sensor 100. Since the rotation angle sensor module 300 has an ideal arrangement relationship, the center of the circle coincides with the center of the quadrangular region indicated by the dotted line. It can be seen that as the rotation angle changes from 0 ° to 315 ° by 45 °, the direction of the magnetic field vector generated in the region where the rotation angle sensor 100 is positioned also rotates by 45 °.

  FIG. 27 shows an example in which magnetic fields in eight directions are respectively applied to the rotation angle sensor 100 of the rotation angle sensor module 300 having the assembly error of the center axis deviation. That is, FIG. 27 shows the magnetic field generated in the XY plane on which the rotation angle sensor 100 is installed when the rotation magnet 410 rotates at 45 ° intervals in the rotation angle sensor module 300 in which the center axis deviation shown in FIG. The direction is indicated by arrows. A plurality of circles in FIG. 27 respectively indicate the rotating magnets 410 as in FIG. 26, and a quadrangle indicated by a dotted line in the circle indicates the position of the rotation angle sensor 100. Since the center axis shift has occurred, a shift has occurred between the center of the circle and the center of the quadrangular region indicated by the dotted line.

  When the rotating magnet 410 is rotated, when the rotation angle θ is 45 °, 135 °, 225 °, or 315 °, a magnetic field vector in a direction different from the rotation angle θ of the rotating magnet 410 is generated in the rectangular region. It can be seen that an angle nonlinearity error occurs. On the other hand, when the rotation angle θ is 0 °, 90 °, 180 °, or 270 °, the direction of the magnetic field vector generated in the rectangular region and the direction of the applied magnetic field substantially coincide with each other, so that the angle nonlinearity error is reduced. I understand that. That is, it can be seen that the direction of the magnetic field input to the rotation angle sensor 100 varies according to the rotation angle θ of the rotating magnet 410, and the variation varies so as to indicate sin (2θ) with respect to the angle θ.

FIG. 28 shows an example of the Hall electromotive force signal (V _X , V _Y ) having a center axis shift. Such distortion of the Hall electromotive force signal _(V X, _{V Y)} is similar to an example of a Hall electromotive force signal having a mismatch of magnetic sensitivity shown in FIG. _{9 (V X, V Y)} , ( Equation 13) And the calibration parameter can be calculated using the equation (17). Similarly, even when the rotation angle sensor module 300 has an assembly error that causes eccentricity and inclination of the rotating magnet 410, when the fluctuation of the generated angle nonlinearity error indicates a periodic function related to the rotation angle of the rotating magnet 410, The calculation unit 220 can calculate the calibration parameter using Equations (12) to (18).

  Next, the parameter supply unit 230 supplies the calibration parameters calculated by the calculation unit 220 to the storage unit 180 of the rotation angle sensor 100 for storage (S530). As described above, the calibration parameter generation apparatus 200 according to the present embodiment rotates the rotating magnet 410 to a predetermined rotation angle, applies a magnetic field in a plurality of directions to the rotation angle sensor 100, and generates an angular nonlinearity error. Can be used to generate calibration parameters that correct angular non-linearity errors due to assembly errors of the rotation angle sensor module 300. Thereby, the rotation angle sensor 100 can correct | amend the angle nonlinearity error resulting from an assembly error using the said calibration parameter.

The calibration parameter generation device 200 according to the present embodiment described above acquires magnetic field detection signals (V _X (θ _n ), V _Y (θ _n )) as output signals from the rotation angle sensor 100 with respect to the rotational position θ _n of the magnet. The example to do was explained. Instead of this, the calibration parameter generation device 200 may acquire the angle signal φ (θ _n ) as an output signal. In this case, the schematic configuration of the rotation angle sensor 100 is substantially the same as the schematic configuration shown in FIG.

In this case, the calibration parameter generation apparatus 200 responds to the acquisition unit 210 applying the magnetic field in the N direction to the rotation angle sensor 100 by rotating the rotating magnet 410 and setting it to N angles θ _n. The angle signal φ (θ _n ) output from the rotation angle sensor 100 is acquired. Then, the calculation unit 220 calculates a calibration parameter based on an error parameter obtained by substituting the angle θ _n and the angle signal φ (θ _n ) into a predetermined periodic function. More specifically, the calculation unit 220 calculates an error parameter (A, B, C, D) using Equation (19), and calculates a calibration parameter for canceling the error parameter.

  As described above, the calibration parameter generation apparatus 200 of the present embodiment can generate calibration parameters for calibrating the rotation angle sensor 100 and the rotation angle sensor module 300, respectively. Further, by applying a magnetic field in a plurality of directions to the rotation angle sensor 100 using the magnetic field applying device 30 and the rotating magnet 410, the calibration parameter generating device 200 can generate each calibration parameter by the same procedure. it can.

  Thus, for example, first, the calibration parameter generation device 200 generates calibration parameters for the rotation angle sensor 100 to calibrate the rotation angle sensor 100, and then assembles the rotation angle sensor module 300, and after the assembly, When the calibration parameter generation device 200 generates and calibrates the calibration parameters of the rotation angle sensor 100, the rotation angle sensor module 300 can output an angle signal with reduced angle nonlinearity error. Further, the calibration of the rotation angle sensor module 300 is performed after the rotation angle sensor module 300 is assembled without performing the calibration of the rotation angle sensor 100, so that the angle non-linearity error and the rotation angle in the rotation angle sensor 100 are performed. It is possible to collectively calibrate angular non-linearity errors caused by assembly errors when the sensor module 300 is assembled.

  FIG. 29 shows an example of a simulation result of an angular non-linearity error generated by the rotation angle sensor module 300 according to this embodiment. FIG. 29 shows an angle non-linearity error (φ (θ) −θ) when a center axis deviation occurs between the rotating magnet 410 and the rotation angle sensor 100. In FIG. 29, the horizontal axis represents the rotation angle θ of the rotating magnet 410, and the vertical axis represents the angle nonlinearity error (φ (θ) −θ) calculated by simulation. Angular nonlinearity that occurs as the amount of misalignment increases as 0.5 mm (square plot in the figure), 1.0 mm (diamond plot), and 2.0 mm (triangle plot) It can be seen that the sex error also increases and fluctuates to indicate sin (2θ) with respect to the rotation angle θ.

30 to 32 show examples of experimental results obtained by actually calibrating the rotation angle sensor 100 of the present embodiment. The magnetic field application device 30 applies magnetic fields in a plurality of directions to the rotation angle sensor 100. FIG. 30 shows an example of the magnetic field detection signals (V _X (θ _n ), V _Y (θ _n )) acquired from the rotation angle sensor 100 by the acquisition unit 210 according to the present embodiment. The horizontal axis in FIG. 30 indicates the angular position of the input magnetic field to the rotation angle sensor 100, and the vertical axis indicates the magnetic field detection intensity of the Hall element pair. It can be seen from FIG. 30 that the rotation angle sensor 100 detects magnetic field detection signals (V _X (θ _n ), V _Y (θ _n )) that change periodically according to the rotating magnetic field.

FIG. 31 shows an example of the measurement result of the angle nonlinear error of the rotation angle sensor 100 according to this embodiment. FIG. 31 shows angular nonlinear errors corresponding to the measurement results of the magnetic field detection signals (V _X (θ _n ), V _Y (θ _n )) shown in FIG. The horizontal axis in FIG. 31 indicates the angular position of the input magnetic field to the rotation angle sensor 100, and the vertical axis indicates the magnitude of the angle nonlinear error (φ (θ) −θ). Figure 31 is an offset V _{Os_x} the X-axis _{direction, Y} axis direction of the offset V _{Os_y,} exhibits an angular nonlinear error when a mismatch of the magnetic sensitivity, and non-orthogonality errors α are mixed, varies with respect to the angular position θ is Periodic functions overlap to show complex shapes.

The calibration parameter generation apparatus 200 according to the present embodiment acquires the magnetic field detection signals (V _X (θ _n ), V _Y (θ _n )) illustrated in FIG. 30, and formulas (Equation 12) to (Equation 15). The error parameters (V _os — _x , V _os — _y , A _x −A _y , α) are used (−0.052 (% FS), −0.107 (% FS), −0.490 ( % FS), -0.0146 °). Here, “FS” means full scale, and “% FS” indicates percentage intensity with respect to full scale. The calibration parameter generation device 200 calculates a calibration parameter from the error parameter using Equations (16) to (18), and the rotation angle sensor 100 performs calibration using the calibration parameter.

  FIG. 32 shows an angle nonlinear error after the rotation angle sensor 100 according to the present embodiment has executed calibration. The horizontal axis in FIG. 32 indicates the angular position of the input magnetic field to the rotation angle sensor 100, and the vertical axis indicates the magnitude of the angle nonlinear error (φ (θ) −θ). It can be seen that the angle nonlinear error is reduced as compared with FIG.

  FIG. 33 and FIG. 34 show an example of experimental results obtained by actually calibrating the rotation angle sensor module 300 of the present embodiment. FIG. 33 shows an example of the measurement result of the angle nonlinear error of the rotation angle sensor 100 according to this embodiment. The horizontal axis in FIG. 33 indicates the angular position of the rotating magnet 410, and the vertical axis indicates the magnitude of the angle nonlinear error. FIG. 33 shows a measurement result of the angle nonlinear error in a state where the rotation angle sensor 100 calibrated using the calibration parameters is assembled into the rotation angle sensor module 300.

  More specifically, FIG. 33 shows the measurement result of the angle nonlinear error when an assembly error having a center axis deviation of about 5 mm occurs between the rotation angle sensor 100 and the rotation magnet 410. That is, among the fluctuations of the angle non-linear error with respect to the angular position θ of the rotating magnet 410 of the angle non-linear error in FIG. 33, the component that fluctuates as sin (2θ) indicates the fluctuation of the center axis deviation. Further, the fluctuation component different from sin (2θ) among fluctuations of the angle nonlinear error is fluctuation caused by eccentricity and the inclination of the rotating magnet 410.

The calibration parameter generation device 200 according to the present embodiment includes the angle signal φ (θ _{n of the} rotation angle sensor module 300 having the angle nonlinearity error illustrated in FIG. 33 at N angular positions θ _n as rotation positions of the rotating magnet 410. ) And the error parameters (A, B, C, D) are calculated as (0.564 °, 0.185 °, -1.99 °, 0.398 °) using the equation (20). did. The calibration parameter generation apparatus 200 calculates a calibration parameter from the error parameter, and the rotation angle sensor 100 performs calibration using the calibration parameter and the equation (21).

  FIG. 34 shows an angle nonlinear error after the rotation angle sensor 100 according to the present embodiment has executed calibration. The horizontal axis in FIG. 34 indicates the angular position of the rotating magnet 410, and the vertical axis indicates the magnitude of the angle nonlinear error (φ (θ) −θ). Compared with FIG. 33, it can be seen that the angle nonlinear error is reduced. As described above, the calibration parameter generation device 200 uses the magnetic field application device 30 and the rotating magnet 410 to generate a calibration parameter that reduces the angle nonlinearity error of the rotation angle sensor 100 and the rotation angle sensor module 300, and performs the rotation. The angle sensor 100 and the rotation angle sensor module 300 can be calibrated.

In addition, the calibration parameter generation apparatus 200 can generate calibration parameters that reduce angular nonlinearity errors based on a plurality of factors. In addition, the calibration parameter generation apparatus 200 performs calculations using substantially the same correlation function before and after the assembly of the rotation angle sensor module 300, thereby calibrating the rotation angle sensor 100 and the rotation angle sensor module 300. Parameters can be generated.
Further, the calibration of the rotation angle sensor module 300 is performed after the rotation angle sensor module 300 is assembled without performing the calibration of the rotation angle sensor 100, so that the angle non-linearity error and the rotation angle in the rotation angle sensor 100 are performed. It is possible to collectively calibrate angular non-linearity errors caused by assembly errors when the sensor module 300 is assembled.

  The rotation angle sensor 100 of the above embodiment has been described as an example including the first Hall element pair 110 and the second Hall element pair 120. Here, the rotation angle sensor 100 detects an error of the rotation angle sensor that outputs the angle signal and the amplitude signal of the rotating body according to the detection result of the magnetic field of the first axis and the magnetic field of the second axis. The magnetic field detection element is not limited to a Hall element. For example, the rotation angle sensor 100 may include a plurality of GMR (Giant Magneto-Resistance) elements and / or TMR (Tunnel Magneto-Resistance) elements that detect the magnetic field of the first axis and the magnetic field of the second axis. Good.

  FIG. 35 shows an example of a hardware configuration of a computer 1900 that functions as the calibration parameter generation apparatus 200 according to the present embodiment. A computer 1900 according to this embodiment is connected to a CPU peripheral unit having a CPU 2000, a RAM 2020, a graphic controller 2075, and a display device 2080 that are connected to each other by a host controller 2082, and to the host controller 2082 by an input / output controller 2084. An input / output unit having a communication interface 2030, a hard disk drive 2040, and a DVD drive 2060; a legacy input / output unit having a ROM 2010, a flexible disk drive 2050, and an input / output chip 2070 connected to the input / output controller 2084; Is provided.

  The host controller 2082 connects the RAM 2020 to the CPU 2000 and the graphic controller 2075 that access the RAM 2020 at a high transfer rate. The CPU 2000 operates based on programs stored in the ROM 2010 and the RAM 2020 and controls each unit. 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 displays it on the display device 2080. Instead of this, the graphic controller 2075 may 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 to 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.

  The input / output controller 2084 is connected to the ROM 2010, the flexible disk drive 2050, and the relatively low-speed input / output device of the input / output chip 2070. The ROM 2010 stores a boot program that the computer 1900 executes at startup and / or a program that depends on the hardware of the computer 1900. 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 inputs / outputs various input / output devices via, for example, a parallel port, a serial port, a keyboard port, a mouse port, and the like. Connect to controller 2084.

  A 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 causes the computer 1900 to function as the acquisition unit 210, the calculation unit 220, and the parameter supply unit 230.

  The information processing described in the program is read into the computer 1900, whereby the acquisition unit 210, the calculation unit 220, and the parameter supply unit 230, which are specific means in which the software and the various hardware resources described above cooperate. Function as. And by this specific means, the calculation or processing of information according to the purpose of use of the computer 1900 in the present embodiment is realized, whereby the specific calibration parameter generation device 200 according to the purpose of use is constructed.

  As an example, when communication is performed between the computer 1900 and an external device or the like, the CPU 2000 executes a communication program loaded on the RAM 2020 and executes a communication interface based on the processing content described in the communication program. A communication process is instructed to 2030. Under the control of the CPU 2000, the communication interface 2030 reads 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, and sends it to the network. The reception data transmitted or received from the network is written 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. Instead, the CPU 2000 transfers the storage device or the communication interface 2030 as the transfer source. The transmission / reception data may be transferred by reading the data from the data and writing the data to the communication interface 2030 or the storage device of the transfer destination.

  In addition, the CPU 2000 includes all or necessary portions of files or databases stored in an external storage device such as the hard disk drive 2040, DVD drive 2060 (DVD-ROM 2095), and flexible disk drive 2050 (flexible disk 2090). Are read into the RAM 2020 by DMA transfer or the like, and various processes are performed on the data on the RAM 2020. Then, CPU 2000 writes the processed data back to the external storage device by DMA transfer or the like. In such processing, since the RAM 2020 can be regarded as temporarily holding the contents of the external storage device, 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 types of information such as various programs, data, tables, and databases in the present embodiment are stored on such a storage device and are subjected to information processing. Note that the CPU 2000 can also store a part of the RAM 2020 in the cache memory and perform reading and writing on the cache memory. Even in such a form, the cache memory bears a part of the function of the RAM 2020. Therefore, in the present embodiment, the cache memory is also included in the RAM 2020, the memory, and / or the storage device unless otherwise indicated. To do.

  In addition, the CPU 2000 performs various operations, such as various operations, information processing, condition determination, information search / replacement, etc., described in the present embodiment, specified for the data read from the RAM 2020 by the instruction sequence of the program. Is written back to the RAM 2020. For example, when performing the condition determination, the CPU 2000 determines whether the various variables shown in the present embodiment satisfy the conditions such as large, small, above, below, equal, etc., compared to other variables or constants. When the condition is satisfied (or not satisfied), the program branches to a different instruction sequence or calls a subroutine.

  Further, the CPU 2000 can search for 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 displays the plurality of entries stored in the storage device. The entry that matches the condition in which the attribute value of the first attribute is specified is retrieved, and the attribute value of the second attribute that is stored in the entry is read, thereby associating with the first attribute that satisfies the predetermined condition The attribute value of the specified second attribute can be obtained.

  The program or module shown above may be stored in an external recording medium. As a recording medium, in addition to the flexible disk 2090 and the DVD-ROM 2095, an optical recording medium such as a DVD, Blu-ray (registered trademark), or a CD, a magneto-optical recording medium such as an MO, a tape medium, a semiconductor such as an IC card, etc. A memory or the like can be used. Further, 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 will be apparent to those skilled in the art that various modifications or improvements can be added to the above-described embodiment. It is apparent from the scope of the claims that the embodiments added with such changes or improvements can be included in the technical scope of the present invention.

  The order of execution of each process such as operations, procedures, steps, and stages in the apparatus, system, program, and method shown in the claims, the description, and the drawings is particularly “before” or “prior to”. It should be noted that the output can be realized in any order unless the output of the previous process is used in the subsequent process. Regarding the operation flow in the claims, the description, 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.

DESCRIPTION OF SYMBOLS 10 Board | substrate, 30 Magnetic field application apparatus, 42 1st coil part, 44 2nd coil part, 46 3rd coil part, 48 4th coil part, 100 rotation angle sensor, 110 1st Hall element pair, 112 1st Hall element, 114 2nd Hall element, 120 2nd Hall element pair, 122 3rd Hall element, 124 4th Hall element, 130 Magnetic focusing plate, 140 X-axis signal output unit, 142 Amplifying unit, 144 AD conversion unit, 150 Y-axis signal Output unit, 152 amplification unit, 154 AD conversion unit, 160 angle signal calculation unit, 170 input / output unit, 180 storage unit, 190 error correction unit, 200 calibration parameter generation device, 210 acquisition unit, 220 calculation unit, 230 parameter supply unit 300 rotation angle sensor module, 410 rotating magnet, 412 rotating shaft, 420 motor, 1900 controller 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 (24)

A method for calibrating a rotation angle sensor that detects a magnetic field in the X-axis direction and a magnetic field in the Y-axis direction on the XY plane, and detects a rotation angle in the XY plane of a rotating magnet that rotates around the rotation axis,
An installation step of installing the rotation angle sensor on the XY plane and a magnetic field in N directions (N is an integer of 3 or more) having different directions by an angle equal to 360 degrees divided into N on the XY plane Applying a magnetic field to each of the sensors;
Obtaining an output signal output from the rotation angle sensor in response to application of the magnetic field in the N direction;
A calculation step of calculating a calibration parameter for calibrating the rotation angle sensor based on the output signal;
Storing the calibration parameter in the storage unit of the rotation angle sensor;
A method for calibrating a rotation angle sensor. The obtaining step outputs the angle θ _n (n = 0, 1,..., N−1) corresponding to each angle θ _n of the magnetic field in the N direction with respect to a predetermined direction on the XY plane. Obtain N angle signals φ (θ _n ) of the rotation angle sensor,
2. The rotation angle according to claim 1, wherein the calculating step calculates the calibration parameter based on an error parameter obtained by substituting the angle θ _n and the angle signal φ (θ _n ) into a predetermined periodic function. Sensor calibration method. The rotation angle sensor calibration method according to claim 2, wherein the calibration parameter is a parameter for canceling the error parameter from each of the angle signals φ (θ _n ). The acquisition step is output corresponding to each angle θ _n (n = 0, 1,..., N−1) of the magnetic field in the N direction with respect to a predetermined direction on the XY plane. Obtaining magnetic field detection signals in the X-axis direction and the Y-axis direction of the rotation angle sensor;
The calculation step calculates the calibration parameter based on a correlation between the magnetic field detection signals in the X-axis direction and the Y-axis direction and a predetermined periodic function into which the angle θ _n is substituted. The rotation angle sensor calibration method according to claim 1. The calibration parameter is:
A first parameter for calibrating an offset of the magnetic field detection signal in the X-axis direction, a second parameter for calibrating an offset of the magnetic field detection signal in the Y-axis direction, and the magnetic field detection signals in the X-axis direction and the Y-axis direction. 5. The method according to claim 4, further comprising: at least one of a third parameter that calibrates a sensitivity mismatch and a fourth parameter that calibrates a non-orthogonality error of the magnetic field detection signal in the X-axis direction and the Y-axis direction. Calibration method of rotation angle sensor. A rotation magnet that rotates around a rotation axis, and a rotation angle sensor that detects a rotation angle of the rotation magnet in the XY plane by detecting a magnetic field in the X-axis direction and a magnetic field in the Y-axis direction on the XY plane. A method for calibrating an angular sensor module, comprising:
A magnetic field applying step of rotating the rotating magnet by 360 degrees by N equal angles and applying magnetic fields in different directions in N directions (N is an integer of 3 or more) to the rotation angle sensor;
Obtaining an output signal output from the rotation angle sensor in response to application of the magnetic field in the N direction;
A calculation step of calculating a calibration parameter for calibrating the rotation angle sensor based on the output signal;
Storing the calibration parameter in the storage unit of the rotation angle sensor;
A method for calibrating a rotation angle sensor module. In the obtaining step, the rotation angle output corresponding to each angle θ _n (n = 0, 1,..., N−1) of the rotating magnet with respect to a predetermined direction on the XY plane. Obtain N angle signals φ (θ _n ) of the sensor,
The rotation angle according to claim 6, wherein the calculating step calculates the calibration parameter based on an error parameter obtained by substituting the angle θ _n and the angle signal φ (θ _n ) into a predetermined periodic function. Sensor module calibration method. The rotation angle sensor module calibration method according to claim 7, wherein the calibration parameter is a parameter for canceling the error parameter from each of the angle signals φ (θ _n ). The obtaining step outputs the rotation corresponding to each angle θ _n (n = 0, 1,..., N−1) of the rotating magnet with respect to a predetermined direction on the XY plane. Obtaining magnetic field detection signals in the X-axis direction and the Y-axis direction of the angle sensor;
The calibration step calculates the calibration parameter based on a correlation between the magnetic field detection signals in the X-axis direction and the Y-axis direction and a predetermined periodic function into which the angle θ _n is substituted. The rotation angle sensor module calibration method according to claim 1. The calibration parameter is:
A first parameter for calibrating an offset of the magnetic field detection signal in the X-axis direction, a second parameter for calibrating an offset of the magnetic field detection signal in the Y-axis direction, and the magnetic field detection signals in the X-axis direction and the Y-axis direction. 10. The method according to claim 9, further comprising: at least one of a third parameter for calibrating a sensitivity mismatch of the first and a fourth parameter for calibrating a non-orthogonality error of the magnetic field detection signal in the X-axis direction and the Y-axis direction. Calibration method of rotation angle sensor module. A rotation angle sensor calibration step of performing the rotation angle sensor calibration method according to claim 1;
An assembly step of assembling a rotation angle sensor module comprising the calibrated rotation angle sensor and a rotating magnet that rotates about a rotation axis;
A rotation angle sensor module calibration stage for executing the rotation angle sensor module calibration method according to any one of claims 6 to 8,
A method for calibrating a rotation angle sensor module. A rotation angle sensor calibration stage for performing the rotation angle sensor calibration method according to any one of claims 1, 4, and 5;
An assembly step of assembling a rotation angle sensor module comprising the calibrated rotation angle sensor and a rotating magnet that rotates about a rotation axis;
A rotation angle sensor module calibration stage for performing the rotation angle sensor module calibration method according to any one of claims 6, 9 and 10.
A method for calibrating a rotation angle sensor module. An acquisition unit that detects a magnetic field in the X-axis direction and a magnetic field in the Y-axis direction on the XY plane, and acquires an output signal of a rotation angle sensor that detects a rotation angle in the XY plane of the rotating magnet that rotates around the rotation axis;
A calculation unit for calculating a calibration parameter for calibrating the rotation angle sensor based on the output signal;
A parameter supply unit that supplies the calibration parameter to the storage unit of the rotation angle sensor and stores the calibration parameter;
With
The acquisition unit outputs a magnetic field in an N direction (N is an integer of 3 or more) having different directions by an angle obtained by dividing 360 degrees into N on the XY plane in response to application to the rotation angle sensor. A calibration parameter generation device that obtains an output signal to be obtained from the rotation angle sensor. The acquisition unit is output corresponding to each angle θ _n (n = 0, 1,..., N−1) of the magnetic field in the N direction with respect to a predetermined direction on the XY plane. Obtain N angle signals φ (θ _n ) of the rotation angle sensor,
The calibration parameter according to claim 13, wherein the calculation unit calculates the calibration parameter based on an error parameter obtained by substituting the angle θ _n and the angle signal φ (θ _n ) into a predetermined periodic function. Generator. The calibration parameter generation device according to claim 14, wherein the calibration parameter is a parameter for canceling the error parameter from each of the angle signals φ (θ _n ). The acquisition unit is output corresponding to each angle θ _n (n = 0, 1, 2,..., N−1) of the magnetic field in the N direction with respect to a predetermined direction on the XY plane. Obtaining magnetic field detection signals in the X-axis direction and the Y-axis direction of the rotation angle sensor,
The calculation unit calculates the calibration parameter based on a correlation between the magnetic field detection signals in the X-axis direction and the Y-axis direction and a predetermined periodic function into which the angle θ _n is substituted. The calibration parameter generating device according to claim 1. The calibration parameter is:
A first parameter for calibrating an offset of the magnetic field detection signal in the X-axis direction, a second parameter for calibrating an offset of the magnetic field detection signal in the Y-axis direction, and the magnetic field detection signals in the X-axis direction and the Y-axis direction. 17. The method according to claim 16, further comprising: at least one of a third parameter that calibrates a sensitivity mismatch and a fourth parameter that calibrates a non-orthogonality error of the magnetic field detection signal in the X-axis direction and the Y-axis direction. Calibration parameter generator. An X-axis signal output unit that magnetoelectrically converts a magnetic field in the X-axis direction and outputs a magnetic field detection signal in the X-axis direction;
A Y-axis signal output unit that magnetoelectrically converts a magnetic field in the Y-axis direction and outputs the magnetic field detection signal in the Y-axis direction;
A storage for storing at least one calibration parameter for calibrating the error of the angle signal;
An error correction unit that corrects errors in the magnetic field detection signals in the X-axis direction and the Y-axis direction based on the calibration parameters and outputs error correction signals in the X-axis direction and the Y-axis direction, respectively;
An angle signal calculation unit that calculates the corrected angle signal based on the error correction signals in the X-axis direction and the Y-axis direction;
A rotation angle sensor. An X-axis signal output unit that magnetoelectrically converts a magnetic field in the X-axis direction and outputs a magnetic field detection signal in the X-axis direction;
A Y-axis signal output unit that magnetoelectrically converts a magnetic field in the Y-axis direction and outputs the magnetic field detection signal in the Y-axis direction;
An angle signal calculation unit that calculates an angle signal based on the magnetic field detection signals in the X-axis direction and the Y-axis direction;
A storage unit for storing at least one calibration parameter for calibrating the error of the angle signal;
An error correction unit for correcting an error of the angle signal based on the calibration parameter;
A rotation angle sensor.   The storage unit reduces an error proportional to at least one of the sine of the angle signal, the cosine of the angle signal, the sine of twice the angle signal, and the cosine of twice the angle signal. The rotation angle sensor according to claim 19, wherein an error parameter to be stored is stored as the calibration parameter. The storage unit reduces an error proportional to at least two of a sine of the angle signal, a cosine of the angle signal, a sine of twice the angle signal, and a cosine of twice the angle signal. An error parameter to be stored as the calibration parameter,
The error correction unit includes the error parameter corresponding to at least two of a sine of the angle signal, a cosine of the angle signal, a sine of twice the angle signal, and a cosine of twice the angle signal. Are linearly combined,
The rotation angle sensor according to claim 19, wherein the angle signal is corrected by subtracting the linearly combined value from the angle signal. The rotation angle sensor according to any one of claims 18 to 21,
A rotating magnet having a rotation axis in a direction substantially perpendicular to the XY plane and provided above the rotation angle sensor;
A rotation angle sensor module.   The program which makes a computer perform the calibration method of the rotation angle sensor as described in any one of Claim 1 to 5.   The program which makes a computer perform the calibration method of the rotation angle sensor module as described in any one of Claims 6-10.

Images