JP7256610B2 - Detection device, method, system, calculation device, and calculation method - Google Patents

Description

The present invention relates to detection devices, methods, systems, calculation devices, and calculation methods.

2. Description of the Related Art A detection device is known that detects the rotation angle of a rotating member such as a motor shaft based on the output of a two-phase sine wave sensor. In such a detection device, the angle error for one rotation of the rotating shaft of the motor is obtained in advance as a numerical string and stored, and when the actual rotation angle is detected, the stored numerical string is read out to correct the detected value. There is a way. Further, in the detection device, the coefficient obtained by Fourier series expansion of the angle error information is stored in advance, and when the detection device is started, etc., the coefficient is read out and the angle error data obtained by inverse Fourier transform is used to There is a method of correcting the detected value (see Patent Document 1). There is also a method of individually improving components that cause detection errors by increasing assembly accuracy of motors and the like.
Patent Document 1 Japanese Patent Application Laid-Open No. 4-125409

However, the correction based on the angle error data sometimes has a lower correction accuracy due to an assembly error or the like. In addition, the adjustment cost increases in order to improve the assembly accuracy.

In order to solve the above problems, in a first aspect of the present invention, there is provided a detection device for detecting a rotation angle of a rotating body, which acquires first magnetic field data that changes according to rotation of the rotating body. an acquisition unit, a second acquisition unit that acquires second magnetic field data that changes in a phase different from the first magnetic field data according to the rotation of the rotating body, and an angle signal based on the first magnetic field data and the second magnetic field data. A detection device is provided that includes an angle calculation unit that outputs an angle signal, and a correction unit that corrects an angle signal using an inclination of the angle signal.

According to a second aspect of the present invention, there is provided a method for detecting a rotation angle of a rotating body, comprising the steps of obtaining first magnetic field data that changes according to the rotation of the rotating body; Acquiring second magnetic field data that changes in phase different from the first magnetic field data; outputting an angle signal based on the first magnetic field data and the second magnetic field data; and compensating for .

In a third aspect of the present invention, a motor, a first magnetic field sensor that outputs first magnetic field data that changes according to the rotation of the motor, and a phase that is different from that of the first magnetic field data that changes according to the rotation of the motor a second magnetic field sensor for outputting second magnetic field data, a detecting device according to the first aspect for detecting the rotation angle of the motor based on the first magnetic field data and the second magnetic field data, and the detection result of the rotation angle of the motor and a motor control circuit for controlling rotation of the motor in response.

In a fourth aspect of the present invention, there is provided a calculation device for calculating a correction parameter for correcting an angle signal indicating an electrical angle having a plurality of cycles per rotation of a rotating body, wherein at least one of the plurality of cycles a slope calculation unit that calculates the slope of the angle signal of the period; and the difference between the angle signal of at least one period and the straight line having the slope of the angle signal of the at least one period is subjected to Fourier series expansion to obtain a correction coefficient. and an offset calculation unit for calculating an offset at a transition point of a plurality of cycles of the angle signal obtained by matching the slopes of the angle signals of a plurality of cycles per rotation of the rotating body. A computing device is provided that outputs correction parameters including the slope of the angle signal, a correction factor, and an offset.

According to a fifth aspect of the present invention, there is provided a calculation method for calculating a correction parameter for correcting an angle signal indicating an electrical angle having a plurality of cycles per rotation of a rotating body, wherein at least one of the plurality of cycles a slope calculation step of calculating the slope of the angle signal of the period; performing Fourier series expansion on the difference between the angle signal of at least one period and the straight line having the slope of the angle signal of the at least one period to obtain a correction factor an offset calculation step of calculating an offset at transition points of a plurality of cycles of the angle signal in which the slopes of the angle signals of a plurality of cycles per rotation of the rotating body are matched; a slope of the angle signal; and outputting correction parameters including correction factors and offsets.

It should be noted that the above summary of the invention does not list all the necessary features of the invention. Subcombinations of these feature groups can also be inventions.

1 shows the configuration of a system 10 according to this embodiment. An example of angle signals of detected electrical angles and mechanical angles is shown. The configuration of a detection device 50 according to the present embodiment is shown. 4 shows a flow of calculation of correction parameters in the detection device 50 of the present embodiment. An example of the angle signal corrected in the correction parameter calculation flow in the detection device 50 of the present embodiment is shown. The flow of the actual detection operation in the detection device 50 of this embodiment is shown. An example of the angle signal corrected in the correction parameter calculation flow of another embodiment is shown. 3 shows another configuration of the detection device 50 according to this embodiment. 19 illustrates an example computer 1900 in which aspects of the present embodiments may be implemented in whole or in part.

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. Also, not all combinations of features described in the embodiments are essential for the solution of the invention.

FIG. 1 shows the configuration of a system 10 according to this embodiment. The system 10 calculates an electrical angle indicating the rotation angle of a rotating body such as the motor 20 based on signals output from the first magnetic field sensor 30 and the second magnetic field sensor 40, and calculates a mechanical angle based on the electrical angle. You can The system 10 controls rotation of the motor 20 according to the calculated mechanical angle. The rotating body is, for example, the rotating shaft of the motor 20 or the gear of the motor 20 .

Here, the electrical angle is an angle when one cycle of the sinusoidal or cosine wave signal from the first magnetic field sensor 30 or the second magnetic field sensor 40 is 360 degrees (one cycle). The mechanical angle is an angle (rotational angle of the rotating body) when one rotation of the rotating body is 360 degrees. One cycle of the mechanical angle may correspond to a plurality of cycles of the electrical angle.

The system 10 comprises a motor 20 , a first magnetic field sensor 30 , a second magnetic field sensor 40 , a sensing device 50 and a motor control circuit 60 .

The motor 20 may rotate a gear connected to a rotating shaft to drive a machine tool, an industrial robot, or the like. The gears of the motor 20 may contain magnetic material.

The first magnetic field sensor 30 and the second magnetic field sensor 40 have, for example, Hall elements that detect magnetic fields. The first magnetic field sensor 30 and the second magnetic field sensor 40 are arranged, for example, near the gear and between the magnet and the gear. The rotation of the gear changes the distance between the first magnetic field sensor 30 and the second magnetic field sensor 40 and the gear, and a magnetic field that changes the magnetic flux density is applied to the first magnetic field sensor 30 and the second magnetic field sensor 40. be. The first magnetic field sensor 30 and the second magnetic field sensor 40 may be arranged at mutually shifted positions so that the applied magnetic field has a phase difference. The first magnetic field sensor 30 outputs first magnetic field data that changes according to the rotation of the motor 20 . The second magnetic field sensor 40 outputs second magnetic field data that changes in a phase different from that of the first magnetic field data according to the rotation of the motor 20 . The first magnetic field sensor 30 and the second magnetic field sensor 40 generate, for example, sine wave or cosine wave electrical signals (A phase signal and B phase signal) having a phase difference of 90 degrees with respect to the magnetic flux density of the applied magnetic field. ) are output as magnetic field data.

The detection device 50 is wired or wirelessly connected to the first magnetic field sensor 30 and the second magnetic field sensor 40 . The detection device 50 receives the first magnetic field data and the second magnetic field data from the first magnetic field sensor 30 and the second magnetic field sensor 40, and determines the rotation angle of the motor 20 based on the first magnetic field data and the second magnetic field data. To detect. The detection device 50 includes a first acquisition section 100 , a second acquisition section 110 , an electrical angle calculation section 120 , an electrical angle correction section 130 , a mechanical angle calculation section 140 and a mechanical angle correction section 150 .

The first acquisition unit 100 and the second acquisition unit 110 acquire first magnetic field data and second magnetic field data from the first magnetic field sensor 30 and the second magnetic field sensor 40, respectively. The electrical angle calculation unit 120 is connected to the first acquisition unit 100 and the second acquisition unit 110, and calculates the electrical angle based on the first magnetic field data and the second magnetic field data. The electrical angle correction section 130 is connected to the electrical angle calculation section 120 and corrects the calculated electrical angle. The mechanical angle calculator 140 is connected to the electrical angle corrector 130 and calculates a mechanical angle from the corrected electrical angle. The mechanical angle corrector 150 is connected to the mechanical angle calculator 140 , corrects the calculated mechanical angle, and outputs an angle signal indicating the corrected mechanical angle to the motor control circuit 60 .

The motor control circuit 60 is wired or wirelessly connected to the detection device 50 and the motor 20 , and controls the rotation speed, rotation direction, etc. of the motor 20 according to the angle signal from the detection device 50 . The motor control circuit 60 may control the current that flows through each coil of the motor 20 .

FIG. 2 shows an example of angle signals of electrical angles and mechanical angles detected by the detection device 50 . FIG. 2 shows a signal for one rotation of the rotating body, and shows, as an example, a case in which one mechanical angle cycle corresponds to three electrical angle cycles. In (a) and (d) of FIG. 2, the horizontal axis represents time and the vertical axis represents voltage. (a) and (d) of FIG. 2 show an ideal value and an actual pulse waveform obtained by comparing the sine wave of the first magnetic field data acquired by the first acquisition unit 100 using the center voltage of the sine wave as a threshold. shows the detected value of In (b), (c), (e), and (f) of FIG. 2, the horizontal axis indicates time and the vertical axis indicates angle. (b) and (e) of FIG. 2 show the ideal value and the actual detected value of the angular signal of the electrical angle calculated by the detection device 50 based on the first magnetic field data and the second magnetic field data. (c) and (f) of FIG. 2 show the ideal value and the actual detected value of the angle signal of the mechanical angle calculated by the detection device 50 based on the electrical angle.

The ideal values in (a), (b) and (c) of FIG. 2 are values when there is no assembly error of the motor 20 and no error occurs in detection by the detection device 50 . When there is no assembly error or the like, the plurality of cycles of the sine wave of the first magnetic field data output by the first magnetic field sensor 30 are uniform. A plurality of periods of the pulse wave to be generated are uniform. The same applies to the second magnetic field data output by the second magnetic field sensor 40 in this case. As shown in (b) of FIG. 2, the electrical angle calculated based on the first magnetic field data and the second magnetic field data similarly has a uniform length over a plurality of periods, and is shown in (c) of FIG. As shown, the mechanical angle calculated based on such an electrical angle has a linear ideal value over one cycle.

In actual detection, there are errors in the assembly of the motor 20 and the like, so errors occur in the values detected by the detection device 50 as shown in (d), (e) and (f) of FIG. The actual detected values in (e) and (f) of FIG. 2 are values detected by the detecting device 50 and not corrected by the electrical angle corrector 130 and the mechanical angle corrector 150 . If there is an assembly error or the like, a plurality of cycles of the sinusoidal wave of the first magnetic field data output by the first magnetic field sensor 30 varies per rotation of the rotating body. Furthermore, the lengths of the plurality of cycles of the pulse wave detected by the detection device 50 similarly vary per rotation of the rotating body. In such a case, as shown in (e) of FIG. 2, the electrical angle calculated based on the first magnetic field data and the second magnetic field data similarly has non-uniform lengths in a plurality of cycles, and As shown in (f) of 2, the mechanical angle calculated based on the electrical angle has an error corresponding to the disturbance of the periodicity of the electrical angle.

Therefore, if the errors in the detected values are corrected on the premise that the lengths of a plurality of cycles of the electrical angle per one rotation of the rotating body are uniform, the values shown in (d), (e) and (f) of FIG. 2 are obtained. Periodic disturbances such as those shown degrade the accuracy of the electrical or mechanical angle correction.

FIG. 3 shows a more detailed configuration of the detection device 50 according to this embodiment. The detection device 50 corrects the angle signal with a correction parameter calculated using the inclination of each period of the electrical angle, and detects the rotation angle of the rotating body. The detection device 50 uses the stored correction parameter to detect the detected angle signal in the correction parameter calculation operation of calculating and storing the correction parameter using the inclination of the angle signal in advance, and in the rotation control of the motor 20 and the like. and the actual detection operation of correcting and outputting.

The detection device 50 includes a first acquisition unit 100, a second acquisition unit 110, a first comparator 300, a second comparator 310, a counter 320, a signal adjustment unit 330, an electrical angle calculation unit 120, It includes an electrical angle correction section 130 , a mechanical angle calculation section 140 , a mechanical angle correction section 150 and a storage section 340 . In the detection device 50, the components other than the electrical angle correction section 130, the mechanical angle correction section 150, and the storage section 340 perform the same processing in the correction parameter calculation operation and the actual detection operation. good.

At least one of the electrical angle calculator 120 and the mechanical angle calculator 140 may function as an angle calculator, and at least one of the electrical angle corrector 130 and the mechanical angle corrector 150 may function as a corrector.

The first acquisition unit 100 acquires first magnetic field data from the first magnetic field sensor 30 and outputs the first magnetic field data to the signal adjustment unit 330 and the first comparator 300 . The second acquisition unit 110 acquires the second magnetic field data from the second magnetic field sensor 40 and outputs the second magnetic field data to the signal adjustment unit 330 and the second comparator 310 . The first acquisition unit 100 and the second acquisition unit 110 may receive the first magnetic field data and the second magnetic field data by wire or wirelessly, amplify them, and output them.

The first comparator 300 and the second comparator 310 are connected to the first acquisition unit 100 and the second acquisition unit 110, respectively, and compare the voltages of the signals of the first magnetic field data and the second magnetic field data with the threshold voltage. , output a pulse signal indicating the comparison result. The threshold voltage may be, for example, the center voltage between the maximum voltage and the minimum voltage of the signal of the first magnetic field data or the second magnetic field data, and may be 0V as an example.

A counter 320 is connected to the first comparator 300 and the second comparator 310 . The counter 320 may count up the rising and falling edges of the pulse signals from the first comparator 300 and the second comparator 310 and output wave number information. Wavenumber information is, for example, the accumulated number of rising and falling edges, or information indicating to which cycle of the electrical angle per rotation of the rotating body the acquired magnetic field data belongs (for example, the electrical angle in one cycle of the mechanical angle period number, etc.).

The signal conditioning unit 330 is connected to the first acquisition unit 100 and the second acquisition unit 110 . The signal adjuster 330 has analog-to-digital converters 331 and 332 , an offset/gain/phase calculator 339 , offset adjusters 333 and 334 , gain adjusters 335 and 336 , and phase adjusters 337 and 338 .

The analog-to-digital converters 331 and 332 convert analog signals of the magnetic field data from the first acquisition section 100 and the second acquisition section 110 into digital signals. Offset/gain/phase calculator 339 is connected to analog-to-digital converters 331 and 332 , counter 320 , and storage 340 . The offset/gain/phase calculator 339 calculates the offset, gain, and phase adjustment parameters of the digital signals from the analog-to-digital converters 331 and 332 according to the wavenumber information from the counter 320, and outputs them to the storage unit 340. . Note that the offset/gain/phase calculator 339 may calculate an adjustment parameter independent of the wavenumber information without using the wavenumber information from the counter 320 .

The offset adjustment units 333 and 334 are connected to the analog-to-digital converters 331 and 332 and the storage unit 340, and adjust the offset of the digital signal according to adjustment parameters. As an example, the offset adjustment units 333 and 334 adjust the offset so that the center voltage between the maximum voltage and the minimum voltage of the digital signal is 0V. The gain adjustment units 335 and 336 are connected to the offset adjustment units 333 and 334 and the storage unit 340, and adjust the gain of the digital signal according to the adjustment parameters. For example, the gain adjusters 335 and 336 adjust gains so that the amplitude of the digital signal of the first magnetic field data and the amplitude of the digital signal of the second magnetic field data are the same. Phase adjusters 337 and 338 are connected to gain adjusters 335 and 336 and memory 340 and adjust the phase of the digital signal according to the adjustment parameter. As an example, the phase adjusters 337 and 338 adjust the phase difference between the digital signal of the first magnetic field data and the digital signal of the second magnetic field data to be a predetermined phase difference. Phase adjusters 337 and 338 output adjusted signals A and B. FIG.

The electrical angle calculator 120 is connected to the signal adjuster 330 and calculates an electrical angle ΘE0 based on the signal A of the first magnetic field data and the signal B of the second magnetic field data. The electrical angle calculator 120 may calculate an electrical angle (electrical interpolation angle) ΘE0 from the signals A and B using the arctangent, and output the angle signal ΘE0. The angle signal ΘE0 may indicate an electrical angle having a plurality of cycles per rotation of the rotating body.

The electrical angle correction section 130 is connected to the electrical angle calculation section 120 and corrects the angle signal .THETA.E0 from the electrical angle calculation section 120 using the inclination of the angle signal .THETA.E0. The electrical angle correction unit 130 may correct the angle signal ΘE0 using different slopes of the angle signal ΘE0 depending on which of a plurality of cycles each electrical angle ΘE0 during one rotation of the rotating body is positioned. . The electrical angle corrector 130 has a tilt calculator 350 , a straight line generator 351 , a difference calculator 352 , a coefficient calculator 353 , a difference corrector 354 , and a tilt corrector 355 .

The inclination calculator 350 is connected to the electrical angle calculator 120 and the counter 320, receives the angle signal ΘE0 from the electrical angle calculator 120, and calculates the inclination of the angle signal ΘE0 in at least one cycle out of a plurality of cycles. do. In the correction parameter calculation operation, the tilt calculator 350 receives the angle signal ΘE0 indicating the electrical angle for a plurality of cycles per rotation of the rotating body, and calculates the tilt k0 of the angle signal ΘE0 for each cycle of the electrical angle. , to the storage unit 340 and the straight line generation unit 351 .

Straight line generator 351 is connected to slope calculator 350 and counter 320 . In the correction parameter calculation operation, the straight line generator 351 generates a straight line of the reference electrical angle ΘEref having the slope k0 received from the slope calculator 350 and outputs the reference electrical angle ΘEref for each cycle of the electrical angle. good.

The difference calculator 352 is connected to the electrical angle calculator 120 and the straight line generator 351, and has an angle signal ΘE0 of at least one cycle out of a plurality of cycles and a slope k0 of the angle signal ΘE0 of the at least one cycle. Calculate the difference information between the straight line. In the correction parameter calculation operation, the difference calculator 352 may output the difference obtained by subtracting the corresponding reference electrical angle ΘEref from the detected electrical angle ΘE0 for each period of the electrical angle, as difference information. .

The coefficient calculator 353 is connected to the difference calculator 352 , the counter 320 and the straight line generator 351 . The coefficient calculator 353 performs Fourier series expansion on the difference between the angle signal .THETA.E0 of at least one cycle and the straight line having the slope k0 of the angle signal .THETA.E0 of the at least one cycle, and calculates the correction coefficient. In the correction parameter calculation operation, the coefficient calculator 353 may calculate a correction coefficient for each electrical angle cycle by performing Fourier series expansion on the difference for at least one electrical angle cycle calculated by the difference calculator 352 . . The coefficient calculation unit 353 outputs the calculated correction coefficient and stores it in the storage unit 340 .

Difference correction section 354 is connected to electrical angle calculation section 120 and storage section 340 . The difference correction unit 354 corrects the angle signal ΘE0 from the electrical angle calculation unit 120 using difference information obtained from the inverse Fourier function to which the correction coefficients stored in the storage unit 340 are applied. During the correction parameter calculation operation and before the actual detection operation, the difference correction unit 354 reads the correction coefficient corresponding to the period of the electrical angle ΘE0 to be corrected from the storage unit 340, and applies the correction coefficient to the inverse Fourier function. , and the difference information at the time point corresponding to the electrical angle ΘE0 to be corrected may be derived. The difference correction unit 354 may correct the electrical angle ΘE0 based on the difference information in the correction parameter calculation operation and the actual detection operation, and output an angle signal ΘE1 indicating the corrected electrical angle.

The tilt correction unit 355 is connected to the difference correction unit 354 and the storage unit 340, and matches the tilts of the angle signals of a plurality of cycles per rotation of the rotating body. In the correction parameter calculation operation, the tilt correction unit 355 receives the electrical angles ΘE1 for a plurality of cycles in one rotation of the rotating body from the difference correction unit 354, and reads the tilt k0 for each cycle of the electrical angle from the storage unit 340. , the electrical angle .THETA.E1 may be corrected so that the slope k0, which differs for each cycle of the electrical angle, is matched. In the correction parameter calculation operation, the tilt correction section 355 may store the difference in electrical angle before and after the tilt correction in the storage section 340 as a correction parameter. On the other hand, in the actual detection operation, the tilt correction unit 355 may read the difference between the electrical angles before and after the tilt correction or the tilt k0 for each period from the storage unit 340 as a correction parameter, and correct the electrical angle ΘE1. The electrical angle tilt corrector 355 may output the corrected electrical angle ΘE2.

Mechanical angle calculator 140 is connected to electrical angle corrector 130 and memory 340 and calculates mechanical angle ΘM0 from electrical angle ΘE2 and wavenumber information from counter 320 . Mechanical angle calculator 140 derives from the wave number information in which cycle the electrical angle . The mechanical angle ΘM0 can be calculated from . The mechanical angle calculator 140 outputs an angle signal ΘM0 indicating the calculated mechanical angle.

Mechanical angle correction section 150 is connected to mechanical angle calculation section 140 and output terminal OUT, and corrects angle signal ΘM0 from mechanical angle calculation section 140 . The mechanical angle corrector 150 has an offset calculator 360 and an offset adder 361 .

The offset calculation unit 360 is connected to the mechanical angle calculation unit 140 and the storage unit 340, and calculates offsets at transition points of a plurality of periods of the angle signals of the electrical angles whose tilts are matched by the tilt correction unit 355. FIG. Here, the transition point is the time point at which the electrical angle transitions to different adjacent cycles, and the offset at the transition point is the mechanical angle offset at the time point corresponding to the transition point. In the operation of calculating the correction parameter, the offset calculator 360 combines the offset ΘMoff of the mechanical angle ΘM0 at the portion corresponding to the transition point of a plurality of cycles of the electrical angle with the mechanical angle ΘM0 calculated by the mechanical angle calculator 140 and the ideal It may be calculated using the mechanical angle ΘMi. The offset calculator 360 may store in advance the ideal mechanical angle ΘMi externally input by the user or the like during the initial adjustment of the detection device 50 or the like. Here, the ideal mechanical angle ΘMi may be the same as that shown in FIG. 2C, and may be a mechanical angle when there is no assembly error of the motor 20 and no error occurs in detection by the detection device 50. . The offset calculation unit 360 outputs the calculated offset ΘMoff to the storage unit 340 for storage.

Offset addition section 361 is connected to storage section 340 and mechanical angle calculation section 140 , and adds offset ΘMoff at transition points of a plurality of cycles of the angle signal to angle signal ΘM 0 from mechanical angle calculation section 140 . The offset adder 361 may read from the storage 340 the offset ΘMoff corresponding to the angle signal ΘM0 and different for each period of the electrical angle before the actual detection operation. In an actual detection operation, the offset adding section 361 may add an electrical angle period offset ΘMoff corresponding to the angle signal ΘM0.

The storage unit 340 may be, for example, a nonvolatile memory such as a nonvolatile RAM, ROM, or hard disk. Storage unit 340 is connected to counter 320 , offset/gain/phase calculator 339 , slope calculator 350 , coefficient calculator 353 , and offset calculator 360 . In the correction parameter calculation operation, the storage unit 340 stores the correction coefficient received from the coefficient calculation unit 353, the slope k0 from the slope calculation unit 350, the difference from the slope correction unit 355, and the offset received from the offset calculation unit 360. ΘMoff and at least one correction parameter may be stored in association with the period of the corresponding electrical angle. The storage unit 340 may determine from the wavenumber information from the counter 320 which electrical angle period in one rotation of the rotor corresponds to the correction parameter, and associate the correction parameter with the electrical angle period. The storage unit 340 may read the correction parameter for each electrical angle period before the actual detection operation.

FIG. 4 shows the flow of the correction parameter calculation operation in the detection device 50 according to this embodiment. In this embodiment, as an example, one cycle of the mechanical angle corresponds to three cycles of the electrical angle. Here, the detection device 50 may calculate the correction parameters during calibration of the detection device 50 or the like. Further, the detection device 50 may calculate the correction parameter using the magnetic field data or the angle signal detected in the previous detection operation.

In S400, the first acquisition unit 100 and the second acquisition unit 110 acquire first magnetic field data and second magnetic field data from the first magnetic field sensor 30 and the second magnetic field sensor 40, respectively. Signal adjusting section 330 adjusts the acquired first magnetic field data and second magnetic field data, respectively, and outputs first magnetic field data signal A and second magnetic field data signal B to electrical angle calculating section 120 .

In S410, the electrical angle calculation unit 120 may calculate the electrical angle ΘE0 from the signals A and B using the arctangent equation (Equation 1).
(Number 1)
ΘE0=Atan2(A, B)

In S420, the electrical angle correction unit 130 performs difference correction of the electrical angle ΘE0. The electrical angle corrector 130 may calculate the correction parameter for each cycle of the mechanical angle or for each cycle of the electrical angle.

As an example, the slope calculator 350 may calculate the slope k0 of a straight line connecting the starting point and the ending point of each cycle of the electrical angle ΘE0. Further, the slope calculator 350 may calculate the slope of a straight line obtained by approximating the electrical angle ΘE0 by the method of least squares as the slope k0 in each cycle. The straight line generator 351 generates, for example, a straight line of the reference electrical angle ΘEref having a slope k0 from the slope calculator 350, and outputs the reference electrical angle ΘEref at the point corresponding to the electrical angle ΘE0. The difference calculation unit 352 may calculate the difference by subtracting the reference electrical angle ΘEref from the calculated electrical angle ΘE0 using Equation (2).
(Number 2)
Difference = ΘE0 - ΘEref

As an example, the coefficient calculation unit 353 performs Fourier series expansion on the difference from the difference calculation unit 352 for each period of the electrical angle to calculate the correction coefficients a1 to a8 using Equation (3). The coefficient calculation unit 353 causes the storage unit 340 to store the calculated correction coefficients a1 to a8.
(Number 3)
ΘE0−ΘEref≈a1×sinΘ+a2×cosΘ+a3×sin2Θ+a4×cos2Θ+a5×sin3Θ+a6×cos3Θ+a7×sin4Θ+a8×cos4Θ

As an example, the difference correction unit 354 derives the difference from the inverse Fourier function to which the correction coefficients a1 to a8 read from the storage unit 340 are applied, and subtracts the difference from the electrical angle ΘE0 to correct the difference, using equation (4). do. The difference corrector 354 outputs the corrected electrical angle ΘE1 to the tilt corrector 355 .
(Number 4)
ΘE1=ΘE0−(a1×sinΘE0+a2×cosΘE0+a3×sin2ΘE0+a4×cos2ΘE0+a5×sin3ΘE0+a6×cos3ΘE0+a7×sin4ΘE0+a8×cos4ΘE0)

Here, the electrical angle correction section 130 may perform difference correction multiple times. The electrical angle correction unit 130, for example, processes the electrical angle ΘE1 corrected by the difference correction unit 354 again with the inclination calculation unit 350, the straight line generation unit 351, the difference calculation unit 352, and the coefficient calculation unit 353 to obtain a correction coefficient. a1-2 to a8-2 may be calculated. The electrical angle corrector 130 may correct the electrical angle ΘE1 by using the correction coefficients a1-2 to a8-2 by the difference corrector 354 in the same manner as described above.

In S430, the tilt corrector 355 corrects the tilt of the electrical angle ΘE1. The inclination corrector 355 makes a plurality of cycles of the electrical angle ΘE1 in one cycle of the mechanical angle substantially the same slope (for example, the same slope as the cycle of the ideal electrical angle as shown in FIG. 2B). can be corrected as follows. For example, the tilt correction unit 355 receives the corresponding tilt k0 from the tilt calculator 350 for each period of the electrical angle, generates the reciprocal 1/k0, and converts the reciprocal 1/k0 to the tilt k0 of the electrical angle ΘE1. Multiply. As a result, the inclination corrector 355 can correct the inclination of the electrical angle ΘE1 over a plurality of periods to be approximately 1.

Here, the tilt correction unit 355 may similarly correct the tilt of the electrical angle ΘE1 corrected by the difference correction unit 354 using the tilt k1 recalculated by the tilt calculation unit 350 .

The tilt corrector 355 outputs the corrected electrical angle ΘE2 to the mechanical angle calculator 140 . The inclination corrector 355 may obtain the difference between the electrical angle ΘE1 and the electrical angle ΘE2 and store it in the storage 340 as a correction parameter.

In S440, the mechanical angle calculator 140 calculates a mechanical angle ΘM0 from the received electrical angle ΘE2 and wavenumber information. As an example, in this embodiment, the mechanical angle calculator 140 converts the electrical angle of 0 to 360 degrees into the mechanical angle of 0 to 120 degrees when the wave number information indicates the first cycle of the electrical angle during one rotation of the rotating body. Since they correspond, the mechanical angle ΘM0 may be calculated from the electrical angle ΘE2. The mechanical angle calculator 140 outputs the calculated mechanical angle ΘM0 to the mechanical angle corrector 150 .

In S450, the offset calculator 360 calculates an offset ΘMoff of a portion corresponding to a transition point between a plurality of cycles of the electrical angle in one cycle of the mechanical angle. As an example, the offset calculator 360 calculates an offset ΘMoff between the ideal mechanical angle ΘMi and the calculated mechanical angle ΘM0. The offset calculation unit 360 causes the storage unit 340 to store the calculated offset ΘMoff.

When the detection device 50 calculates the correction parameters for at least one cycle of the mechanical angle, the detection device 50 may end the calculation operation of the correction parameters.

FIG. 5 shows an example of the angle signal corrected in the correction parameter calculation flow in the detection device 50 of the present embodiment. In (a) to (e) of FIG. 5, the horizontal axis indicates time and the vertical axis indicates angle. In (a) of FIG. 5, the electrical angle ΘE0 calculated in S410 is indicated by a solid line, and the reference electrical angle ΘEref is indicated by a dotted line. As shown in FIG. 5A, the first, second, and third periods of the electrical angle .THETA.E0 have different lengths due to an assembly error of the motor 20 or the like.

FIG. 5(b) shows the electrical angle .theta.E1 after difference correction in S420 with a solid line, and the electrical angle .theta.E0 before the difference correction with a dotted line. As shown in FIG. 5B, the difference correction unit 354 subtracts the difference from the linear reference electrical angle ΘEref (dotted line in FIG. 5A) having the slope k0 of each period from the electrical angle ΘE0. Therefore, the electrical angle .theta.E1 after the difference correction is substantially the same linear shape as the reference electrical angle .theta.Eref. Here, the difference calculator 352 calculates the difference between the electrical angle ΘE0 in the first period and the reference electrical angle ΘEref1, the electrical angle ΘE0 in the second period and the electrical angle ΘEref2 in the third period, and the electrical angle ΘE0 in the third period. and the reference electrical angle ΘEref3 may be calculated.

FIG. 5(c) shows the electrical angle .THETA.E2 corrected in S430 by a solid line, and the electrical angle .THETA.E1 before the tilt correction by a dotted line. As shown in (c) of FIG. 5, the first, second, and third cycles of the electrical angle ΘE1 are corrected so that the slopes k0 are the same.

In (d) of FIG. 5, the mechanical angle ΘM0 for one period calculated in S440 is indicated by a solid line, and the ideal mechanical angle ΘMi is indicated by a dotted line. Since the inclination is corrected in S430, the calculated mechanical angle .THETA.M0 has an offset .THETA.Moff with respect to the ideal mechanical angle .THETA.Mi at the position corresponding to the transition point of each cycle of the electrical angle. The mechanical angle ΘM0 is at a position corresponding to the transition point between the first and second periods of the electrical angle, and the offset ΘMoff1 is at a position corresponding to the transition point between the second and third periods of the electrical angle. An offset ΘMoff2 occurs at .

FIG. 5(e) shows the mechanical angle .THETA.M1 offset-corrected in S450 by a solid line, and the mechanical angle .THETA.M0 before offset correction by a dotted line. The offset calculator 360 calculates the offset ΘMoff1 and the offset ΘMoff2 based on the ideal mechanical angle ΘMi. The offset adder 361 adds an offset ΘMoff of the period of the corresponding electrical angle to the mechanical angle ΘM0. As shown in FIG. 5(e), the corrected mechanical angle .THETA.M1 has substantially the same value as the ideal mechanical angle .THETA.Mi.

The detection device 50 of the present embodiment as described above can calculate and store a correction parameter that takes into consideration the disturbance of the periodicity of the electrical angle per mechanical angle cycle.

FIG. 6 shows the flow of the actual detection operation in the detection device 50 of this embodiment. Note that S600, S610, and S630 of FIG. 6 are the same as the processing of S400, S410, and S440 of FIG. 4, respectively, so detailed description thereof will be omitted.

In S620, the electrical angle correction unit 130 corrects the electrical angle ΘE0. The difference correction unit 354 reads the correction coefficient from the storage unit 340 before the detection operation, for example, when the power of the detection device 50 is turned on, derives the difference by the inverse Fourier function to which the correction coefficient is applied, and calculates the mechanical angle 1 A period's difference may be stored in the difference correction unit 354 . The difference corrector 354 may correct the electrical angle ΘE0 calculated by the electrical angle calculator 120 by subtracting the difference at the time corresponding to the electrical angle ΘE0. The difference corrector 354 outputs the corrected electrical angle ΘE1 to the tilt corrector 355 .

The tilt correction unit 355 may read correction parameters for one cycle of the mechanical angle from the storage unit 340 before the detection operation, for example, when the power of the detection device 50 is turned on. The tilt correction unit 355 may read out from the storage unit 340 the difference in electrical angle before and after the tilt correction in the correction parameter calculation operation. Further, the tilt correction unit 355 may read the tilt k0 corresponding to each cycle of the electrical angle ΘE1 from the storage unit 340, and derive the difference between the electrical angles before and after the tilt correction from the tilt k0. For example, the tilt correction unit 355 may obtain the difference at each point between a straight line with a slope of k0 and a straight line with a slope of 1, which have the same origin. Then, the tilt corrector 355 may apply (for example, add) the difference, which is a correction parameter, to the electrical angle ΘE1 in the detection operation. In addition, the inclination correction unit 355 may correct the electrical angle ΘE1 in the same manner as S430 in the correction parameter calculation operation flow.

In S640, the offset adder 361 performs offset correction of the mechanical angle ΘM0. The offset adder 361 reads the offset ΘMoff of the mechanical angle ΘM0 for one cycle of the mechanical angle from the storage 340 before the detection operation, for example, when the power of the detector 50 is turned on. can be stored inside. The offset adder 361 may correct the mechanical angle ΘM0 calculated by the mechanical angle calculator 140 by subtracting the offset ΘMoff corresponding to the mechanical angle ΘM0. For example, the offset adder 361 uses the offset ΘMoff1 shown in FIG. may be offset-corrected using the offset ΘMoff2 shown in FIG. 5(d).

In S650, the offset adding section 361 outputs the angle signal ΘM1 of the corrected mechanical angle from the output terminal OUT. Thereby, for example, the motor control circuit 60 can control the rotation of the motor 20 in accordance with the angle signal ΘM1 output from the output terminal OUT of the detection device 50 .

With the detection operation of the detection device 50 of the present embodiment as described above, it is possible to correct the detected angle signal in consideration of the disturbance of the periodicity of the electrical angle, and to output the angle signal with high accuracy.

FIG. 7 shows an example of the angle signal corrected in the correction parameter calculation flow in the detection device 50 of another embodiment. The embodiment of FIG. 7 does not correct for the electrical angle, but corrects for the mechanical angle.

(a) of FIG. 7 shows the electrical angle calculated from the magnetic field data detected by the detector 50 . As shown in FIG. 7A, the first, second, and third cycles of the detected electrical angle have different lengths.

FIG. 7(b) shows the mechanical angle for one cycle calculated from the electrical angle of FIG. 7(a) by the detecting device 50 with a solid line, and the reference mechanical angle ΘMref with a dotted line. As shown in FIG. 7B, since the electrical angle is not corrected, the electrical angle error remains in the mechanical angle.

In (c) of FIG. 7, the mechanical angle after the difference correction is indicated by a solid line, and the mechanical angle before the difference correction is indicated by a dotted line. The detection device 50 may correct the mechanical angle using a different inclination for each portion corresponding to each cycle of the electrical angle. For example, the detection device 50 obtains the slope of a straight line connecting the start point and the end point for each portion corresponding to each cycle of the electrical angle, and calculates the relationship between the reference mechanical angle ΘMref having the slope and the calculated mechanical angle. can be calculated. The detection device 50 calculates a reference mechanical angle ΘMref1 for the mechanical angle corresponding to the first cycle of the electrical angle, a reference mechanical angle ΘMref2 for the mechanical angle corresponding to the second cycle of the electrical angle, and a reference mechanical angle ΘMref2 for the mechanical angle corresponding to the second cycle of the electrical angle. The difference may be calculated using the reference mechanical angle ΘMref3 for the mechanical angle corresponding to the third cycle.

The detection device 50 may perform Fourier series expansion on the difference between the reference mechanical angle ΘMref and the calculated mechanical angle to calculate a correction coefficient, and store the correction coefficient in the storage unit 340, as in S420. The detection device 50 may derive the difference from the inverse Fourier function to which the correction coefficient read from the storage unit 340 is applied, and subtract the difference from the mechanical angle for correction, as in S420. As shown in (c) of FIG. 7, the mechanical angle after the difference correction is linear like the reference mechanical angle ΘMref, but the inclination differs for each portion corresponding to each cycle of the electrical angle.

In (d) of FIG. 7, the tilt-corrected mechanical angle is indicated by a solid line, and the ideal mechanical angle ΘMi is indicated by a dotted line. The detection device 50 may correct the inclination of the mechanical angle for each portion corresponding to each period of the electrical angle. As an example, the detection device 50 multiplies the slope calculated for each portion corresponding to each cycle of the electrical angle by the reciprocal of the slope, thereby obtaining a plurality of slopes of the mechanical angle corresponding to a plurality of cycles of the electrical angle. match. As shown in FIG. 7(d), since the tilt is corrected, offsets ΘMoff1 and ΘMoff2 are generated with respect to the ideal mechanical angle ΘMi at portions corresponding to transition points between a plurality of cycles of the electrical angle.

(e) of FIG. 7 shows the offset-corrected mechanical angle with a solid line, and the mechanical angle before the offset correction with a dotted line. Since the offset correction in (e) of FIG. 7 is the same processing as S450 and S640, detailed description thereof will be omitted.

With the detecting device 50 of the present embodiment as described above, it is possible to obtain a correction parameter capable of accurately correcting the mechanical angle in consideration of the disturbance of the periodicity of the electrical angle. The detection device 50 can apply the correction parameter for the mechanical angle calculated in this embodiment to the actual detection operation in the same manner as the correction for the electrical angle and the mechanical angle in FIG.

Note that the detection device 50 of the present embodiment includes at least one of the inclination calculator 350, the straight line generator 351, the difference calculator 352, the coefficient calculator 353, and the offset calculator 360, which are used to calculate the correction parameters. You don't have to. The detection device 50 may store correction parameters calculated in advance by an external device such as a microcomputer in the storage unit 340, and correct the angle signal using the stored correction parameters in an actual detection operation.

Also, the detection device 50 of this embodiment may not have the first comparator 300 , the second comparator 310 and the counter 320 . In this case, the detection device 50 may receive information such as the rotation angle from another detection device provided to detect the rotation angle of the same detection target rotating body, and obtain the wave number information from the information.

At least one of tilt correction and offset correction is not essential for the detection device 50 of the present embodiment, and at least one of the tilt correction unit 355, the offset calculation unit 360, and the offset addition unit 361 is not provided. good too. Further, the detection device 50 of this embodiment may change the order of the correction by the difference correction unit 354 and the correction by the tilt correction unit 355 .

3 includes an offset/gain/phase calculator 339, a slope calculator 350, a straight line generator 351, a difference calculator 352, a coefficient calculator 353 and an offset calculator 360. It is not necessary to have a block for The correction parameter calculation block may be configured as a calculation device separate from the detection device 50 .

The calculation device may receive data detected by the detection device 50, and based on the data, calculate a correction parameter for correcting an angle signal indicating an electrical angle having a plurality of cycles per rotation of the rotating body. The calculator includes an offset/gain/phase calculator 339 , a slope calculator 350 , a straight line generator 351 , a difference calculator 352 , a coefficient calculator 353 and an offset calculator 360 . These configurations may function similarly to the configuration of detection device 50 . The calculation device may output the calculated correction parameters and store them in the storage unit 340 of the detection device 50 . The correction parameters may be used for initial adjustment at the time of shipment of mass production of the detection device 50 .

FIG. 8 shows another configuration of the detection device 50 according to this embodiment. The detection device 50 of FIG. 8 has the same configuration as the detection device 50 of FIG.

The first comparator 300 and the second comparator 310 are connected to the phase adjusters 337 and 338 of the signal adjuster 330, respectively, and compare the signals A and B from the phase adjusters 337 and 338 with the threshold values to obtain a comparison result. A pulse signal indicating the result may be output.

FIG. 9 illustrates an example computer 1900 upon which aspects of the invention may be implemented in whole or in part. Programs installed on the computer 1900 may cause the computer 1900 to function as one or more sections of an operation or apparatus associated with an apparatus according to embodiments of the invention, or may Sections may be executed and/or computer 1900 may be caused to execute processes or steps of such processes according to embodiments of the present invention. Such programs may be executed by CPU 2000 to cause computer 1900 to perform certain operations associated with some or all of the blocks in the flowcharts and block diagrams described herein.

The computer 1900 according to the present embodiment includes a CPU peripheral section having a CPU 2000, a RAM 2020, a graphic controller 2075, and a display device 2080, which are interconnected by a host controller 2082, and an input/output controller 2084, which is connected to the host controller 2082. and a legacy input/output unit having a ROM 2010, a flash memory drive 2050, and an input/output chip 2070 connected to an input/output controller 2084. .

Host controller 2082 connects RAM 2020 to CPU 2000 and graphics controller 2075 that access RAM 2020 at a high transfer rate. The CPU 2000 operates based on programs stored in the ROM 2010 and RAM 2020, and controls each section. 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 . Alternatively, the graphics controller 2075 may internally include a frame buffer for storing image data generated by the CPU 2000 or the like.

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

The I/O controller 2084 is also connected to the ROM 2010 , the flash memory drive 2050 and the I/O chip 2070 , which are relatively low-speed I/O devices. The ROM 2010 stores a boot program executed by the computer 1900 at startup and/or a program depending on the hardware of the computer 1900, and the like. Flash memory drive 2050 reads programs or data from flash memory 2090 and provides them to hard disk drive 2040 via RAM 2020 . The input/output chip 2070 connects the flash memory drive 2050 to the input/output controller 2084 and inputs/outputs various input/output devices via, for example, parallel ports, serial ports, keyboard ports, mouse ports, 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 flash memory 2090, DVD 2095, or IC card and provided by the user. The program is read from the recording medium, installed in hard disk drive 2040 in computer 1900 via RAM 2020, and executed in CPU 2000. FIG. The information processing described in these programs is read by computer 1900 and provides cooperation between the software and the various types of hardware resources described above. An apparatus or method may be configured by implementing the manipulation or processing of information in accordance with the use of computer 1900 .

As an example, when communicating between the computer 1900 and an external device or the like, the CPU 2000 executes a communication program loaded on the RAM 2020, and based on the processing content described in the communication program, the communication interface. 2030 is instructed to perform communication processing. 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 flash memory 2090, or the DVD 2095, and transmits the transmission data to the network. Alternatively, the received data received from the network is written into a receive buffer area or the like provided on the storage device. In this way, the communication interface 2030 may transfer data to and from a storage device using a DMA (direct memory access) method. The transmission/reception data may be transferred by reading the data from and writing the data to the communication interface 2030 or storage device of the transfer destination.

The CPU 2000 also DMAs all or necessary portions of files or databases stored in external storage devices such as the hard disk drive 2040, DVD drive 2060 (DVD 2095), and flash memory drive 2050 (flash memory 2090). The data is read into the RAM 2020 by transfer or the like, and various processes are performed on the data on the RAM 2020 . Then, the CPU 2000 writes the processed data back to the external storage device by DMA transfer or the like. In such processing, the RAM 2020 can be regarded as temporarily holding the contents of the external storage device. Therefore, in this embodiment, the RAM 2020 and the external storage device are collectively referred to as a memory, a storage unit, or a storage device.

Various kinds of information such as various programs, data, tables, databases, etc. in this embodiment are stored in such a storage device, and are subject to information processing. Note that the CPU 2000 can also hold part of the RAM 2020 in cache memory and perform reading and writing on the cache memory. Even in such a form, the cache memory is responsible for part of the functions of the RAM 2020, so in this embodiment, unless otherwise indicated, the cache memory is also included in the RAM 2020, memory, and/or storage device. do.

In addition, the CPU 2000 performs various operations, including various calculations, information processing, condition determination, information search/replacement, etc., which are specified by the instruction sequence of the program, on the data read from the RAM 2020, and which are described in the present embodiment. and write it back to the RAM 2020 . For example, when performing conditional judgment, the CPU 2000 compares the various variables shown in this embodiment with other variables or constants to determine whether or not the conditions such as greater, lesser, greater than, less than or equal to are satisfied. If the condition is satisfied (or not satisfied), branch to a different instruction sequence or call a subroutine.

The CPU 2000 can also search for information stored in a file, database, or the like in the storage device. For example, when a plurality of entries in which attribute values of a first attribute are respectively associated with attribute values of a second attribute are stored in the storage device, the CPU 2000 performs processing of the plurality of entries stored in the storage device. An entry whose attribute value of the first attribute matches the specified condition is searched from among the entries, and the attribute value of the second attribute stored in that entry is read out to associate it with the first attribute that satisfies the predetermined condition. It is possible to obtain the attribute value of the given second attribute.

Also, when a plurality of elements are listed in the description of the embodiment, elements other than the listed elements may be used. For example, when it is stated that "X performs Y using A, B and C," X may perform Y using D in addition to A, B and C.

Although the present invention has been described above using the embodiments, the technical scope of the present invention is not limited to the scope described in the above embodiments. It is obvious to those skilled in the art that various modifications and improvements can be made to the above embodiments. It is clear from the description of the scope of claims that forms with such modifications or improvements can also be included in the technical scope of the present invention.

The execution order of each process such as actions, procedures, steps, and stages in the device, system 10, program, and method shown in the claims, the specification, and the drawings is particularly "before", "before", and "before". It should be noted that it can be implemented in any order unless it is expressly stated as such and the output of a previous process is used in a later process. Regarding the operation flow in the claims, the specification, and the drawings, even if the description is made using "first," "next," etc. for the sake of convenience, it means that it is essential to carry out in this order. not a thing

10 system 20 motor 30 first magnetic field sensor 40 second magnetic field sensor 50 detection device 60 motor control circuit 100 first acquisition unit 110 second acquisition unit 120 electrical angle calculation unit 130 electrical angle correction unit 140 mechanical angle calculation unit 150 mechanical angle correction Section 300 First Comparator 310 Second Comparator 320 Counter 330 Signal Adjustment Sections 331 and 332 Analog-to-Digital Converters 333 and 334 Offset Adjustment Sections 335 and 336 Gain Adjustment Sections 337 and 338 Phase Adjustment Section 339 Offset/Gain/Phase Calculation Section 340 Storage unit 350 Inclination calculation unit 351 Straight line generation unit 352 Difference calculation unit 353 Coefficient calculation unit 354 Difference correction unit 355 Inclination correction unit 360 Offset calculation unit 361 Offset addition unit 1900 Computer 2000 CPU
2010 ROM
2020 RAM
2030 communication interface 2040 hard disk drive 2050 flash memory drive 2060 DVD drive 2070 input/output chip 2075 graphic controller 2080 display device 2082 host controller 2084 input/output controller 2090 flash memory 2095 DVD

Claims (8)

A detection device for detecting the rotation angle of a rotating body,
a first acquisition unit that acquires first magnetic field data that changes according to the rotation of the rotating body;
a second acquisition unit that acquires second magnetic field data that changes in a phase different from that of the first magnetic field data according to the rotation of the rotating body;
an angle calculation unit that outputs an angle signal indicating an electrical angle having a plurality of cycles per rotation of the rotating body based on the first magnetic field data and the second magnetic field data;
a correction unit that corrects the angle signal using the slope of the angle signal, which is the slope of a straight line approximating the electrical angle of at least one cycle of the plurality of cycles;
The correction unit has an offset addition unit that adds an offset at transition points of the plurality of cycles of the angle signal to the angle signal,
The correction unit corrects the angle signal using different inclinations of the angle signal according to which of the plurality of cycles each electrical angle during one rotation of the rotating body is positioned. A detection device for detecting the rotation angle of a rotating body,
a first acquisition unit that acquires first magnetic field data that changes according to the rotation of the rotating body;
a second acquisition unit that acquires second magnetic field data that changes in a phase different from that of the first magnetic field data according to the rotation of the rotating body;
an angle calculation unit that outputs an angle signal indicating an electrical angle having a plurality of cycles per rotation of the rotating body based on the first magnetic field data and the second magnetic field data;
a correction unit that corrects the angle signal using the slope of the angle signal, which is the slope of a straight line approximating the electrical angle of at least one cycle of the plurality of cycles;
The correction unit has a slope calculation unit that calculates a slope of the angle signal in at least one of the plurality of cycles,
The correction unit corrects the angle signal using different inclinations of the angle signal according to which of the plurality of cycles each electrical angle in one rotation of the rotating body is positioned. The correction unit is
a tilt correction unit that matches the tilts of the angle signals of the plurality of cycles per rotation of the rotating body;
2. The detection device according to claim 1 , further comprising an offset calculation unit that calculates the offsets at transition points of a plurality of cycles of the angle signal with the slopes matched. A method for detecting the rotation angle of a rotating body, comprising:
obtaining first magnetic field data that varies according to the rotation of the body of rotation;
acquiring second magnetic field data that changes in phase different from the first magnetic field data according to the rotation of the rotating body;
outputting an angle signal indicating an electrical angle having a plurality of cycles per rotation of the rotating body based on the first magnetic field data and the second magnetic field data;
correcting the angle signal using the slope of the angle signal, which is the slope of a straight line approximating the electrical angle of at least one of the plurality of cycles;
The correcting step includes:
adding offsets at the transition points of the plurality of periods of the angle signal to the angle signal;
correcting the angle signal using a different slope of the angle signal according to which of the plurality of cycles each electrical angle in one rotation of the rotating body is positioned. A method for detecting the rotation angle of a rotating body, comprising:
obtaining first magnetic field data that varies according to the rotation of the body of rotation;
acquiring second magnetic field data that changes in phase different from the first magnetic field data according to the rotation of the rotating body;
outputting an angle signal indicating an electrical angle having a plurality of cycles per rotation of the rotating body based on the first magnetic field data and the second magnetic field data;
correcting the angle signal using the slope of the angle signal, which is the slope of a straight line approximating the electrical angle of at least one of the plurality of cycles;
The correcting step includes:
calculating a slope of the angle signal for at least one period of the plurality of periods;
correcting the angle signal using a different slope of the angle signal according to which of the plurality of cycles each electrical angle in one rotation of the rotating body is positioned. a motor;
a first magnetic field sensor that outputs first magnetic field data that changes according to rotation of the motor;
a second magnetic field sensor that outputs second magnetic field data that changes in a phase different from that of the first magnetic field data according to the rotation of the motor;
The detection device according to any one of claims 1 to 3 , which detects the rotation angle of the motor based on the first magnetic field data and the second magnetic field data;
A system comprising: a motor control circuit that controls rotation of the motor according to a detection result of a rotation angle of the motor. A calculation device for calculating a correction parameter for correcting an angle signal indicating an electrical angle having a plurality of cycles per rotation of a rotating body,
a slope calculation unit that calculates a slope of the angle signal, which is a slope of a straight line approximating the electrical angle of at least one of the plurality of cycles;
a coefficient calculator for calculating a correction coefficient by Fourier series expansion of the difference between the angle signal of at least one cycle and the straight line having the slope of the angle signal of at least one cycle;
an offset calculation unit that calculates an offset at a transition point of the plurality of cycles of the angle signal that matches the slopes of the angle signal of the plurality of cycles per rotation of the rotating body;
The computing device outputs the correction parameters including the slope, the correction factor, and the offset of the angle signal. A calculation method for calculating a correction parameter for correcting an angle signal indicating an electrical angle having a plurality of cycles per rotation of a rotating body, comprising:
a slope calculation step of calculating a slope of the angle signal, which is a slope of a straight line approximating the electrical angle of at least one of the plurality of cycles;
a coefficient calculation step of calculating a correction coefficient by Fourier series expansion of the difference between the angle signal of at least one cycle and the straight line having the slope of the angle signal of at least one cycle;
an offset calculation step of calculating an offset at a transition point of the plurality of cycles of the angle signal in which slopes of the angle signal of the plurality of cycles are matched per one rotation of the rotating body;
and outputting said correction parameters comprising said slope, said correction factor and said offset of said angle signal.

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