JP2006234723A - Method of correcting rotation angle in rotation angle detector - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of correcting a rotation angle in a rotation angle detector, in a rotation angle detecting device for an handle with multiple revolutions used for a car body control system, that corrects mechanical errors, electrical errors, and magnetic errors with less correction data with high precision. <P>SOLUTION: The method uses a motor 9 for rotating a shaft 1 to be inspected, a motor controller 14 for controlling the rotation angle of the motor 9, and an encoder 10 for detecting the rotation angle of the motor 9. By using them, a difference between the rotation angle of the shaft 1 to be inspected that is actually rotated by the motor 9 and a calculated rotation angle of the shaft 1 determined by rotation angle detecting sections 3, 7 is stored in a nonvolatile memory 11 as a correction angle. With the correction angle, the calculated rotation angle of the shaft 1 is corrected. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a rotation angle correction method of a multi-turn steering wheel rotation angle detection device used in a vehicle body control system of an automobile.

  Conventionally, as an apparatus for detecting the rotation angle of a rotating body that rotates multiple times, such as an absolute encoder, a rotation angle measuring method for detecting the rotation angle of a test shaft from the rotation angles of a plurality of rotating bodies having phase differences, The device exists.

As prior art document information related to the invention of this application, for example, Patent Document 1 is known.
JP 63-118614 A

  However, the above-described apparatus has a problem that the detection accuracy of the rotation angle of the shaft to be measured is deteriorated due to the alignment accuracy of the gears, the center deflection, and the detection error in the rotation angle detection unit.

  The present invention is for solving this problem, and an object of the present invention is to provide a highly accurate rotation angle correction method for a rotation angle detector that corrects mechanical errors of gears and electrical errors of a rotation angle detector. To do.

  In order to achieve the above object, the present invention has the following configuration.

  The invention according to claim 1 of the present invention includes a first rotation angle detector disposed at a position facing a target connected to a test shaft, a mechanism for decelerating the rotation of the test shaft, and the speed reduction. A rotation angle detecting device for calculating a rotation angle of the test shaft based on signals from the first rotation angle detection unit and the second rotation angle detection unit. A motor that rotates the test shaft, a motor controller that controls the rotation angle of the motor, and an encoder that detects the rotation angle of the motor. The difference between the rotation angle and the calculated rotation angle of the test axis obtained from the first and second rotation angle detectors is stored in a nonvolatile memory as a correction angle, and the calculation of the test axis is performed with this correction angle. The rotation angle is corrected.

  According to a second aspect of the present invention, the correction angle is stored in a nonvolatile memory for each predetermined rotation angle in the entire detection range to correct the calculated rotation angle of the test shaft, and between the predetermined rotation angles, Correction is performed with a correction angle estimated from an approximate straight line obtained with correction angles stored before and after.

  According to a third aspect of the present invention, the target is a multipolar ring magnet that is magnetized so that the magnetic poles are inverted at equal intervals in the circumferential direction of the test shaft, and a rotation range corresponding to each magnetic pole width. The average error of each magnetic pole is stored in a nonvolatile memory as a correction angle common to each magnetic pole, and the calculated rotation angle of the test axis is corrected by this correction angle.

  In the invention according to claim 4 of the present invention, the target is a gear having convex portions arranged at equal intervals in the circumferential direction of the shaft to be tested, and the average error of each tooth in the rotation range corresponding to each tooth width. The value is stored in a nonvolatile memory as a correction angle common to each tooth, and the calculated rotation angle of the test axis is corrected by this correction angle.

  In the invention according to claim 5 of the present invention, the target is provided with concave portions so that non-concave portions are formed at equal intervals in the circumferential direction of the test shaft, and each concave portion has a rotation range corresponding to each concave portion width. The average value of the errors is stored in a nonvolatile memory as a correction angle common to the respective recesses, and the calculated rotation angle of the test axis is corrected by this correction angle.

  According to a sixth aspect of the present invention, a correction angle common to each target is stored in a nonvolatile memory for each predetermined rotation angle in a rotation range corresponding to the target interval, and the calculated rotation angle of the test axis is corrected. Between the predetermined rotation angles, correction is performed with a correction angle estimated from an approximate straight line obtained with correction angles stored before and after the predetermined rotation angle.

  According to these inventions, correction data with a smaller capacity is stored in a non-volatile memory, and the calculated rotation angle of the test shaft is corrected with this correction data. The operational effect is obtained that the detection accuracy of the calculated rotation angle of the test axis including the magnetic error due to the variation and the electrical error of the rotation angle detection unit and the detection circuit unit can be greatly improved.

  According to the present invention, the decrease in the rotation angle detection accuracy caused by the mechanical error, magnetic error, electrical error, etc. of the multipolar ring magnet and the rotation angle detection unit can be reduced with the correction angle stored in the nonvolatile memory having a smaller capacity. By correcting the rotation angle, the rotation angle detection device capable of improving the rotation angle detection accuracy of the test shaft can be provided in a simple form.

(Embodiment 1)
Hereinafter, Embodiment 1 of the present invention will be described with reference to FIGS.

  FIG. 1 is a configuration diagram of a rotation angle detection device according to Embodiment 1 of the present invention, and FIG. 2 is a configuration diagram of a correction system of the rotation angle detection device. FIG. 3 is a diagram illustrating a signal of the first rotation angle detection unit arranged at a position facing the multipolar ring magnet. FIG. 4 is a diagram showing the relationship between the rotational electrical angle obtained from the Sin signal and Cos signal for one cycle of the first rotational angle detector and the rotational mechanical angle of the test shaft. FIG. 5 is a principle diagram for calculating the multi-rotation rotational mechanical angle of the test shaft from the signal of the first rotation angle detection unit and the signal of the second rotation angle detection unit. FIG. 6 is a diagram showing an example of data obtained by calculating the error included in the calculated rotary mechanical angle of the test shaft for each rotary mechanical angle corresponding to the magnetic pole pitch of the multipolar ring magnet. FIG. 7 is a diagram showing a method for obtaining a corrected approximate straight line from the rotating machine angle error. FIG. 8 is a diagram showing an example of rotating machine angle error data corrected with an average value of rotating machine angle errors of each magnetic pole. FIG. 9 is a diagram showing a method of obtaining a correction approximate straight line from the average value of the rotating machine angle error of each magnetic pole.

  In FIG. 1, a multipolar ring magnet 2 as a target is connected to a test shaft 1, and a first rotation angle detection unit 3 is disposed at a position facing the multipolar ring magnet 2. A worm gear 4 is connected to the shaft 1 to be tested, and a wheel gear 5 is engaged with the worm gear 4. A magnet 6 is disposed at the center of the wheel gear 5, and a second rotation angle detection unit 7 that detects a rotation angle is disposed at a position facing the magnet 6. The motor 9 is attached to the end surface of the test shaft 1, and the encoder 10 detects the rotating mechanical angle of the test shaft 1 by the motor 9.

  In FIG. 2, a non-volatile memory (EEPROM) 11 is for storing correction angles and the like. The CPU 12 is connected to the nonvolatile memory (EEPROM) 11 and the first and second rotation angle detectors 3 and 7 and calculates the rotation angle. The CPU 12 and the motor controller 14 are connected by a serial communication line 13 that transmits and receives an angle signal and a command signal so that signals can be transmitted and received. A motor 9 is attached to the shaft 1 to be tested, and its rotation is driven and controlled with high accuracy by a motor controller 14. The rotation angle of the shaft 1 to be detected is detected with high accuracy by the encoder 10 and is transmitted to the motor controller 14.

  In FIG. 3, the horizontal axis indicates the rotational mechanical angle of the test shaft 1, and the vertical axis indicates the output signal of the first rotation angle detection unit 3. A Sin signal 15 and a Cos signal 16 are output according to the rotation of the test shaft 1.

  In FIG. 4, the horizontal axis indicates the rotational mechanical angle of the test shaft 1, and the vertical axis indicates the rotational electrical angle obtained from the Sin signal 15 and the Cos signal 16 shown in FIG.

  In FIG. 5, the horizontal axis indicates the rotation mechanical angle of the shaft 1 to be detected over the detection range, and the vertical axis indicates the rotation electrical angle obtained from the first rotation angle detection unit 3 in the upper stage and the second in the middle stage. The rotation electrical angle obtained from the rotation angle detection unit 7 is calculated by combining the rotation electrical angles calculated from the signals of the first rotation angle detection unit 3 and the second rotation angle detection unit 7 in the lower stage. 1 shows a rotating mechanical angle.

  Next, a method of detecting the rotation angle of the test shaft 1 with the above configuration will be described.

  In FIG. 1, when the test shaft 1 rotates, the multipolar ring magnet 2 connected to the test shaft 1 rotates. A signal corresponding to the rotation angle of the multipolar ring magnet 2 can be obtained from the first rotation angle detector 3. In the case of this embodiment, since the number of magnetic poles of the multipolar ring magnet 2 is 30, the rotational mechanical angle per magnetic pole is 12 deg (= 360 deg / 30 poles). As shown in FIG. 3, with respect to the rotational mechanical angle (12 deg) per magnetic pole of the multipolar ring magnet 2 attached to the test shaft 1, a Sin signal 15 that is a signal of the first rotational angle detector 3 and The Cos signal 16 changes by one cycle (corresponding to 360 deg of rotation electrical angle). In FIG. 4, an ideal rotating machine angle obtained from the rotating electrical angle 17 calculated from the signal of the first rotation angle detecting unit 3 shown in FIG. The rotating mechanical angle obtained from the rotating electrical angle 17 due to the influence of the magnetization variation and eccentricity of the polar ring magnet 2 or the sensitivity variation and position variation of the first rotation angle detector 3 is the ideal rotational mechanical angle 18. An error is included like the rotating mechanical angle 19. Then, as shown in the upper diagram of FIG. 5, the rotational mechanical angle 19 from 0 deg to 12 deg of the shaft 1 to be measured is obtained with high accuracy and high resolution from the rotational electrical angle 17 obtained from the first rotational angle detector 3. Can do.

  On the other hand, the worm gear 4 connected to the test shaft 1 rotates, and the wheel gear 5 also rotates at a certain reduction ratio. In this example, the reduction ratio is 1/4. The rotation angle of the wheel gear 5 is calculated from a signal from the second rotation angle detector 7 that detects the magnetic field direction of the magnet 6. As shown in the middle of FIG. 5, a rotary mechanical angle 21 of 0 deg to 720 deg, which is the detection range of the shaft 1 to be measured, is obtained from the rotary electrical angle 20 obtained from the Sin signal and Cos signal of the second rotation angle detector 7. be able to. As shown in the lower part of FIG. 5, the rotation obtained from the second rotation angle detection unit 7 indicates which period (magnetic pole) the value of the rotation mechanical angle 19 obtained from the first rotation angle detection unit 3 belongs to. The rotational mechanical angle 22 of the test shaft 1 is determined by determining from the mechanical angle 21. Also in the lower part of FIG. 5, due to the same effect described in FIG.

  Next, a method for improving the rotation angle detection accuracy of the test shaft 1 in the above configuration (reducing the error) will be described.

  FIG. 6 shows a rotary mechanical angle 19 calculated from a rotary electrical angle 17 obtained by inversely converting a Tan signal (= Sin / Cos) calculated from a Sin signal and a Cos signal, which are signals of the first rotation angle detector 3, on the horizontal axis. The rotary machine angle error 24, which is the difference between the rotary machine angle 18 where the test shaft 1 is actually rotated and the rotary machine angle 19, is taken on the vertical axis. In the motor controller 14, the rotation mechanical angle 18 of the test shaft 1 detected by the encoder 10 and the test shaft 1 calculated by the CPU 12 built in the rotation angle detection device 8 obtained via the serial communication line 13. The rotating mechanical angle 19 can be stored synchronously. That is, the motor controller 14 can determine the rotational mechanical angle error 24 with respect to the rotational mechanical angle 19 of the shaft 1 calculated by the rotational angle detection device 8 using (Equation 1).

(Rotational mechanical angle error 24) = (Calculated rotational mechanical angle 19 of the test shaft 1) − (Rotational mechanical angle 18 at which the test shaft 1 is actually rotated) (Equation 1)
FIG. 7 shows an example of data of the rotational machine angle error 24 actually acquired.

  The motor controller 14 transmits the rotary machine angle error 24 to the CPU 12 via the serial communication line 13, and the CPU 12 stores the rotary machine angle error 24 in the nonvolatile memory (EEPROM) 11 for each rotary machine angle 19. Therefore, the CPU 12 can correct the rotational mechanical angle 19 of the shaft 1 to be constantly calculated by using the rotational mechanical angle error 24 (Equation 2).

(Rotating mechanical angle 18 at which the test shaft 1 is actually rotated) = (Calculated rotating mechanical angle 19 of the test shaft 1) − (Rotating mechanical angle error 24) (Equation 2)
However, a large-capacity nonvolatile memory (EEPROM) 11 is required to store the rotating machine angle error 24 over the entire rotation detection range. When the rotation detection range is 720 deg and the resolution is 1 deg, a non-volatile memory capacity of 720 is required.

  Therefore, if the rotating machine angle error 24 obtained every predetermined rotating machine angle (every 3 degrees in the example of FIG. 7) is stored in the nonvolatile memory (EEPROM) 11, the capacity is reduced to 240 (720/3). it can. The rotating machine angle error 24 between certain predetermined rotating machine angles is estimated by an approximate straight line obtained from the rotating machine angle error 24 every 3 degrees.

  Let x be the rotating machine angle between 3 deg and c be the rotating machine angle every 3 deg closest to x. That is, c <x <c + 3. Let m be the rotating machine angle error 24 at (c + 3) and n be the rotating machine angle error 24 at c. An approximate straight line of the rotating machine angle error 24 based on these values is expressed by (Equation 3).

y = (mn). (xc) / 3 + n (Formula 3)
The motor controller 14 rotates the motor 9 and acquires the rotary mechanical angle 18 of the shaft 1 to be tested in synchronization with the encoder 10 every 3 degrees of the rotary mechanical angle 19 obtained from the serial communication line 13. In FIG. 7, the rotational mechanical angle error 24 (n) when the rotational mechanical angle 19 (c) is 0 deg is 0.001 deg, and the rotational mechanical angle error 24 (when the rotational mechanical angle 19 (c + 3) is 3 deg) ( m) is 0.012 deg. The formula for obtaining the rotary mechanical angle error 24 every 0.5 deg when the rotary mechanical angle 19 is 0 deg to 3 deg is obtained by substituting these values into (Equation 3). Y = (0.012-0.001) · (x −0) /3+0.001
= 0.0036 · x + 0.001 (Formula 4)
It becomes. For example, the rotational mechanical angle error 24 when the rotational mechanical angle 19 is 1 deg is 0.0046 deg according to (Equation 4). The rotational mechanical angle error 24 for each deg when the rotational mechanical angle 19 is 3 deg to 6 deg is also obtained by the same method. The rotational mechanical angle 19 of the test shaft 1 calculated based on the rotational mechanical angle error 24 thus obtained is corrected by (Equation 1).

  Further, in order to reduce the capacity of the nonvolatile memory, as shown in FIG. 6, the rotating machine angle (which is one magnetic pole pitch) with respect to the calculated rotating machine angle 19 of the average value 25 of the rotating machine angle error 24 of each magnetic pole (this In the embodiment, it is obtained by (Equation 5) every 12 deg).

Average value 25 = (sum of rotating machine angle errors 24 from 1 to N magnetic poles at a certain rotating machine angle 19) / N (Expression 5)
From the average value 25, a rotary machine angle error 26 is obtained by (Equation 6).

(Rotational mechanical angle error 26) = (Calculated rotational mechanical angle 19 of the test shaft 1) − (Rotational mechanical angle 18 at which the test shaft 1 actually rotates) − (Average value of the rotational mechanical angle error of each magnetic pole) 25) ... (Formula 6)
FIG. 8 is a plot of the rotational machine angle error 26 calculated by substituting the data of FIG. 6 into (Equation 6). Since there is a correlation in the tendency of occurrence of the rotating machine angle error 24 of each magnetic pole shown in FIG. 6, the variation of the rotating machine angle error 26 shown in FIG. It is reduced to ± 0.1 deg or less.

  In the motor controller 14, the rotary mechanical angle 18 of the test shaft 1 detected by the encoder 10 and the rotary mechanical angle 19 of the test shaft 1 calculated by the CPU 12 built in the rotational angle detection device 8 obtained via the serial communication line 13 Thus, the average value 25 of the rotating machine angle error 24 of each magnetic pole obtained from (Equation 1) can be calculated by (Equation 5). This average value 25 is transmitted to the CPU 12 through the serial communication line 13 and stored in the nonvolatile memory (EEPROM) 11 by the CPU 12. Therefore, the CPU 12 always corrects the calculated rotational mechanical angle 19 of the test shaft 1 by using the average value 25 of the rotational mechanical angle error, including the rotational mechanical angle error 26, using (Equation 7). be able to.

(Rotating machine angle 18 at which the test shaft 1 is actually rotated) + (Rotating mechanical angle error 26) = (Calculated rotating mechanical angle 19 of the test shaft 1) − (Average value 25 of rotating mechanical angle error) ... (Formula 7)
Further, a method for reducing the capacity of the nonvolatile memory (EEPROM) 11 will be described with reference to FIG. FIG. 9 is an enlarged view of a part of FIG. If the average value 25 of the rotational mechanical angle error of each magnetic pole as plotted in FIG. 9 is stored in the nonvolatile memory (EEPROM) 11 in the range of 0 deg to 12 deg at intervals of 0.5 deg. 24 capacity is required, but the average value 25 of the rotational mechanical angle error of each magnetic pole obtained for each predetermined rotational mechanical angle (every 2 deg in the example of FIG. 9) is a non-volatile memory (EEPROM) 11. Can be reduced to a capacity of 6 (= 12/2). The average value 25 between certain predetermined rotating machine angles is estimated by an approximate straight line obtained from the average value 25 every 2 degrees.

  Let x be the rotating mechanical angle between two degs, and c1 be the rotating mechanical angle every 2 deg closest to x. That is, c1 <x <c1 + 2. Let m1 be the value of the average value 25 at (c1 + 2) and n1 be the value of the average value 25 at c1. An approximate straight line of the average value 25 based on these values is expressed by (Equation 8).

y1 = (m1-n1). (x-c1) / 2 + n1 (Formula 8)
The motor controller 14 rotates the motor 9, acquires the rotary mechanical angle 19 every 2 deg from the serial communication line 13, and acquires the rotary mechanical angle 18 of the test shaft 1 from the encoder 10. The rotary machine angle error 24 is obtained from the rotary machine angle 18, the rotary machine angle 19 and (Equation 1), and the average value 25 is obtained by (Equation 5).

  In FIG. 9, the value (n1) of the average value 25 when the value (c1) of the rotating machine angle 19 is 0 deg is 0.031 deg, and the average value when the value (c1 + 2) of the rotating machine angle 19 is 2 deg. The value (m1) of 25 is 0.042 deg.

The formula for obtaining the average value 25 every 0.5 deg when the rotational mechanical angle 19 is 0 deg to 2 deg is obtained by substituting these values into (Equation 8). Y1 = (0.042−0.031) · (x−0) ) /2+0.031=0.0055·x+0.031 (Formula 9)
It becomes. For example, the value of the average value 25 when the value of the rotating mechanical angle 19 is 1 deg is 0.0365 deg from (Equation 9). The value of the average value 25 every 0.5 deg from the 2 deg to 4 deg value of the rotating mechanical angle 19 is also obtained in the same manner. The rotational mechanical angle 19 of the test shaft 1 calculated with the average value 25 thus determined is corrected by (Equation 7). Even if the average value 25 shown in FIG. 6 is estimated by the approximate straight line of (Equation 8) and the rotary machine angle error 26 is obtained by (Equation 6), the result is almost the same as the rotary machine angle error 26 shown in FIG. Got.

(Embodiment 2)
Hereinafter, a second embodiment of the present invention will be described with reference to FIG.

  FIG. 10 is a perspective view of the target in the second embodiment. On the outer peripheral surface of the target 27, convex portions made of a magnetic material are arranged at equal intervals in the circumferential direction. The rotation angle detection device including the target 27 has the same shape as the signal of the first rotation angle detection unit in the first embodiment, and the rotation angle can be calculated from this signal. In addition, since the rotation angle detection apparatus using the target of this Embodiment 2 is the same as that of the rotation angle detection apparatus which concerns on Embodiment 1 mentioned above, the description is abbreviate | omitted.

(Embodiment 3)
Hereinafter, Embodiment 3 of the present invention will be described with reference to FIG.

  FIG. 11 is a perspective view of a target in the third embodiment. The target 28 has a cylindrical portion, and concave portions are arranged on the outer peripheral surface of the cylindrical portion so that non-recessed portions are formed at equal intervals in the circumferential direction. The rotation angle detection device including the target 28 has the same shape as the signal of the first rotation angle detection unit in the first embodiment, and the rotation angle can be calculated from this signal. In addition, since the rotation angle detection apparatus using the target of this Embodiment 3 is the same as that of the rotation angle detection apparatus which concerns on Embodiment 1 mentioned above, the description is abbreviate | omitted.

  As described above, the rotation angle detection device according to the present embodiment stores a correction angle for the calculated rotation angle of the test shaft 1 in a non-volatile memory in the detection range or in the rotation range corresponding to each magnetic pole width of the multipolar ring magnet. EEPROM) 11 or a method of storing the correction angle in a non-volatile memory (EEPROM) 11 for every certain rotation angle, a magnetic error, mechanical error, electrical error of a multipolar ring magnet or a rotation angle detector. By correcting the decrease in the rotation angle detection accuracy due to an error with a non-volatile memory having a smaller capacity, it is possible to improve the accuracy of the detected rotation angle of the test shaft.

  The rotation angle correction method of the rotation angle detection device according to the present invention has the effect of being able to detect multiple rotations of the test shaft with high accuracy with a simple configuration using a nonvolatile memory with a smaller capacity. Therefore, it is suitable for use as a rotation angle correction method of a rotation angle detection device used in vehicle power steering or the like.

Configuration diagram of rotation angle detection device according to Embodiment 1 of the present invention Configuration diagram of a correction system of a rotation angle detection device in Embodiment 1 of the present invention The figure which shows the signal of the 1st rotation angle detection part in Embodiment 1 of this invention. The figure which shows the relationship between the rotation electrical angle of the test shaft and rotation mechanical angle in Embodiment 1 of this invention. FIG. 2 is a principle diagram for calculating a multi-rotation rotating mechanical angle of a test shaft in the first embodiment of the present invention. The figure which shows an example of the error contained in the rotation mechanical angle of the calculated test shaft in Embodiment 1 of this invention. The figure which shows the method of calculating | requiring a correction | amendment approximate straight line from the rotation machine angle error in Embodiment 1 of this invention. The figure which shows an example of the rotation machine angle error after correct | amending with the average value of the rotation machine angle error of each magnetic pole in Embodiment 1 of this invention. The figure which shows the method of calculating | requiring a correction | amendment approximate straight line from the average value of the rotation machine angle error of each magnetic pole in Embodiment 1 of this invention. The perspective view of the target in Embodiment 2 of this invention The perspective view of the target in Embodiment 3 of this invention

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Test shaft 2 Multipolar ring magnet 3 1st rotation angle detection part 4 Worm gear 5 Wheel gear 6 Magnet 7 2nd rotation angle detection part 8 Rotation angle detection apparatus 9 Motor 10 Encoder 11 Non-volatile memory (EEPROM)
12 CPU
13 Serial communication line 14 Motor controller 15 Sin signal 16 Cos signal 17, 20 Rotating electrical angle 18, 19, 21, 22 Rotating mechanical angle 23 Ideal rotating mechanical angle 24, 26 Rotating mechanical angle error 25 Average value 27, 28 Target

Claims (6)

A first rotation angle detector disposed at a position facing the target connected to the test shaft, a mechanism for decelerating the rotation of the test shaft, and a second rotation angle detection for detecting the decelerated rotation angle A rotation angle detecting device that calculates a rotation angle of the test shaft based on signals from the first rotation angle detection unit and the second rotation angle detection unit, and a motor that rotates the test shaft, Using a motor controller that controls the rotation angle of the motor and an encoder that detects the rotation angle of the motor, the rotation angle of the test shaft actually rotated by the motor and the first and second rotation angles A rotation angle detection device that stores a difference from the calculated rotation angle of the test axis obtained from the detection unit in a nonvolatile memory as a correction angle, and corrects the calculated rotation angle of the test axis with the correction angle. Rotation angle correction method. The correction angle is stored in a non-volatile memory for each predetermined rotation angle in the entire detection range, and the calculated rotation angle of the test axis is corrected, and between the predetermined rotation angles, from the approximate straight line obtained with the correction angles stored before and after the predetermined rotation angle The rotation angle correction method of the rotation angle detection device according to claim 1, wherein the correction is performed with an estimated correction angle. The target is a multipolar ring magnet that is magnetized so that the magnetic poles are reversed at equal intervals in the circumferential direction of the test shaft, and the average value of the error of each magnetic pole is common to each magnetic pole in the rotation range corresponding to each magnetic pole width. The rotation angle correction method of the rotation angle detection device according to claim 1, wherein the correction angle is stored in a non-volatile memory and the calculated rotation angle of the test axis is corrected by the correction angle. The target is a gear having convex portions arranged at equal intervals in the circumferential direction of the axis to be examined, and a non-volatile memory having an average value of error of each tooth in a rotation range corresponding to each tooth width as a correction angle common to each tooth The rotation angle correction method of the rotation angle detection device according to claim 1, wherein the rotation angle is stored and the calculated rotation angle of the test shaft is corrected by the correction angle. It is assumed that the target is arranged with recesses so that non-recesses are formed at equal intervals in the circumferential direction of the test shaft, and the average error value of each recess in the rotation range corresponding to each recess width is the correction angle common to each recess. The rotation angle correction method for a rotation angle detection device according to claim 1, wherein the rotation angle correction device stores the data in a non-volatile memory and corrects the calculated rotation angle of the test axis by the correction angle. A correction angle common to each target is stored in a non-volatile memory for each predetermined rotation angle in a rotation range corresponding to the target interval, and the calculated rotation angle of the test axis is corrected, and is stored before and after the predetermined rotation angle. 6. The rotation angle correction method for a rotation angle detection device according to claim 3, wherein the correction is performed using a correction angle estimated from an approximate straight line obtained from the correction angle.

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