JP2019219297A - Rotational angle detector - Google Patents

Abstract

To provide a rotational angle detector which allows the reduction of the size of data.SOLUTION: A rotational angle detector 10 includes: a sensor 11 for outputting according to the angle of rotation of a rotational body; a division unit 31 for outputting the result of division by dividing output of the sensor 11; a data table Ta holding a correction value for correcting the result of division to a target output; and an operation unit 33 for operating the angle of rotation, using the data table Ta. Holding the correction value in the data table Ta can reduce the width of data and the data size.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a rotation angle detection device that detects a rotation angle of a rotating body.

  Conventionally, a rotation angle detection device that detects a rotation angle of a rotating body is well known. In the rotation angle detection device described in Patent Literature 1, a magnet that rotates integrally with a rotating body and a magnetic sensor corresponding to the magnet are provided. As the direction of the magnetic flux emitted from the magnet changes according to the rotation of the rotating body, a detection signal corresponding to the change in the direction of the magnetic flux is output from the magnetic sensor. The rotation angle detection device calculates the rotation angle of the rotating body based on the detection signal.

JP 2017-075852 A

  By the way, in such a rotation angle detection device, a data table in which rotation angles corresponding to the detection signals are arranged is stored in order to calculate the rotation angle from the detection signals. The rotation angle detection device compares a detection signal of the magnetic sensor with a data table and obtains a rotation angle corresponding to the detection signal. Here, when trying to increase the resolution of the rotation angle, there is a concern that the size of the data table becomes large. Therefore, there is a need to reduce the data size of the data table.

  SUMMARY OF THE INVENTION It is an object of the present invention to provide a rotation angle detection device that can reduce the data size.

  A rotation angle detection device for solving the above-mentioned problem includes a detection unit whose output changes in accordance with the rotation angle of a rotating body, a calculated value of the rotation angle obtained from an output of the detection unit, and a target calculated value. A data table in which a correction value to be corrected is associated with a value; and a calculation unit that calculates a rotation angle of the rotating body using the data table.

  According to this configuration, the correction values are arranged in the data table. Thus, the size of the data table can be reduced by using the correction value data smaller than the target value data. Therefore, the data size can be reduced.

  In the rotation angle detection device, it is preferable that, in the data table, in each of the regions obtained by dividing the operation value in a predetermined range, the correction value is shared by the regions set as a set.

  According to this configuration, since the data table shares the correction values in a plurality of areas, it is not necessary to hold another correction value for the shared portion. This contributes to a reduction in data size.

  In the rotation angle detection device, in the data table in which the correction values are shared, in the data table before the correction values are shared, the area is inverted at a specified position on the index side of the calculated value. In this case, it is preferable that one or more areas overlap each other and the correction values are shared in the overlapped areas.

  According to this configuration, when the correction value is shared, the region is inverted and the overlapped region is shared, so that the range of the correction value is likely to be approximated. Therefore, it is easy to suppress the deviation of the correction value. Thereby, the error of the rotation angle caused by the deviation of the correction value can be suppressed, which contributes to securing the calculation accuracy of the rotation angle.

  The rotation angle detection device may further include a correction value conversion unit that converts the correction value shared for each group into an ideal value to be taken in each region using a coefficient set for each region. preferable.

  According to this configuration, when sharing the correction value, the deviation of the correction value can be corrected by the coefficient. This further contributes to ensuring the calculation accuracy of the rotation angle.

  The rotation angle detection device according to the present invention enables the data size to be reduced.

FIG. 1 is a configuration diagram of a rotation angle detection device according to a first embodiment. 4 is a graph showing an output from a sensor. 7 is a graph showing the result of division. 4 is a graph showing a relationship between a division result and a target output. 5 is a flowchart illustrating a flow of rotation angle detection according to the first embodiment. Regarding the size of the data table, (a) is a table when target outputs are arranged, and (b) is a table when correction values are arranged. 9 is a graph showing correction values in divided regions. FIG. 6 is a configuration diagram of a rotation angle detection device according to a second embodiment. 9 is a flowchart illustrating a flow of rotation angle detection according to the second embodiment. The figure which shows conversion of the correction value by a coefficient.

<First embodiment>
Hereinafter, a first embodiment of a rotation angle detection device will be described with reference to FIGS.
As shown in FIG. 1, the rotation angle detection device 10 includes a sensor 11 as a detection unit that detects rotation of a rotating body. The sensor 11 is preferably a magnetic sensor that detects the direction of the magnetic flux of a magnet (not shown) that rotates integrally with the rotating body. As the sensor 11, for example, a so-called MR sensor in which four magnetoresistive elements are connected in a bridge shape can be adopted. The sensor 11 includes a first bridge circuit 12 and a second bridge circuit 13 which is inclined by 45 ° in the direction of the detection surface with respect to the first bridge circuit 12. The first bridge circuit 12 (and the second bridge circuit 13) has a circuit configuration by connecting two sets of two magnetoresistive elements arranged in series and connecting them in parallel. The voltage at is output. One end of the two sets of connection points connected in parallel is connected to the power supply via the input terminal Vcc, and the other end is connected to the ground via the input terminal GND.

  In the first bridge circuit 12 and the second bridge circuit 13, a voltage of a predetermined level is applied from a power supply between the input terminal Vcc and the input terminal GND. When a magnetic field is applied from the outside, the resistance value of the magnetoresistive elements constituting the first bridge circuit 12 and the second bridge circuit 13 changes according to the magnetic field (more precisely, the direction of the magnetic flux). The first bridge circuit 12 and the second bridge circuit 13 change the magnetic field applied to them, that is, the midpoint voltage that changes according to the change in the direction of the magnetic flux generated from the magnet rotating integrally with the rotating body. Is output. The sensor 11 differentially amplifies the midpoint voltages output from the first bridge circuit 12 and the second bridge circuit 13, respectively, and outputs a sine wave signal Vs and a cosine wave signal Vc. Note that the combination of the first bridge circuit 12 and the second bridge circuit 13 and the sine wave signal Vs and the cosine wave signal Vc can be appropriately changed.

  As shown in FIG. 2, the sine wave signal Vs and the cosine wave signal Vc output from the sensor 11 change continuously according to the rotation angle θ of the rotating body. The sine wave signal Vs and the cosine wave signal Vc have waveforms that change repeatedly in each cycle. The phase of the cosine wave signal Vc is shifted from the sine wave signal Vs by 1/4 cycle.

  The rotation angle detection device 10 includes a first A / D converter 21 and a second A / D converter 22 that convert the sine wave signal Vs and the cosine wave signal Vc into digital signals and output the digital signals to the microcomputer 20. Hereinafter, the signals (sine wave signal Vs and cosine wave signal Vc) processed by the microcomputer 20 are all digital signals.

  The microcomputer 20 calculates the rotation angle θ of the rotating body based on the inputs from the first A / D converter 21 and the second A / D converter 22. The microcomputer 20 includes a divider 31 for dividing the sine wave signal Vs and the cosine wave signal Vc input from the first A / D converter 21 and the second A / D converter 22. The division unit 31 of the present example divides the absolute value of the sine wave signal Vs and the absolute value of the cosine wave signal Vc into the divisor and the smaller one into the dividend, thereby calculating the division result D.

  As shown in FIG. 3, the division result D repeatedly rises and falls at a predetermined cycle with respect to the rotation angle θ of the rotating body. In the case of this example, the division result D repeatedly rises and falls in the range of “0 to 1” every time the rotation angle θ rotates 45 °. Note that the division result D corresponds to the calculated value of the rotation angle obtained from the output of the detection unit.

  As shown in FIG. 4, the division result D takes a curve that increases from “0” to “1” as the rotation angle θ increases in the range of the rotation angle θ of 0 to 45 °. When the rotation angle θ is obtained from the division result D, the division result D may be converted into a target output Dt (shown by a broken line in FIG. 4) proportional to the rotation angle θ. The target output Dt takes a value in which the output value increases linearly from 0 to 1 when the rotation angle θ increases from 0 to 45 °.

  Returning to FIG. 1, the rotation angle detection device 10 includes a data table Ta used when calculating a rotation angle calculation value from the output of the sensor 11. The data table Ta of the present example is stored in the storage unit 32 of the microcomputer 20. The data table Ta includes a calculated value of the rotation angle θ obtained from the output of the sensor 11 (division result D in this example) and a correction value C for correcting the calculated value to a target value (target output Dt in this example). It is an associated correction table.

  As shown in FIG. 4, in the data table Ta, correction values C corresponding to all the division results D are arranged in the range of the division result D “0 to 1”. The correction value C in this example is set based on the difference between the division result D and the target output Dt. The correction value C is as shown by a dashed line in FIG. The correction value C plotted with respect to the rotation angle θ has a portion where the correction value C increases and a portion where the correction value C decreases as the rotation angle θ increases. Further, the range of the correction value C is smaller than the range of the division result D (“0 to 1” in this example).

  Returning to FIG. 1, the microcomputer 20 includes a calculation unit 33 that calculates the rotation angle θ of the rotating body using the data table Ta. When receiving the division result D, the calculation unit 33 obtains a correction value C corresponding to the division result D by referring to the data table Ta. The data table Ta of this example is prepared when the rotation angle θ is in the range of “0 to 45 °”. The calculation unit 33 calculates the rotation angle θ of the rotating body by applying the rotation angle θ ′ obtained in the range of “0 to 45 °” to one rotation (360 °). The arithmetic unit 33 corrects the division result D to the target output Dt by adding the correction value C to the division result D, and obtains the rotation angle θ ′ in the range of “0 to 45 °”.

  The calculation unit 33 converts the rotation angle θ ′ in the range of “0 to 45 °” into the rotation angle θ in the range of “0 to 360 °”. The arithmetic unit 33 determines whether the division result D is within 360 ° based on the sign of the sine wave signal Vs and the cosine wave signal Vc and the magnitude relationship between the absolute value of the sine wave signal Vs and the absolute value of the cosine wave signal Vc. It is determined which of the eight quadrants at 45 ° intervals falls. Then, the rotation angle θ ′ is converted into the rotation angle θ according to the corresponding quadrant. Thereby, the rotation angle θ in the range of “0 to 360 °” can be obtained only with the data table Ta in the range of “0 to 45 °”.

Next, the operation and effect of the rotation angle detection device 10 according to the first embodiment will be described with reference to FIGS.
As shown in FIG. 5, in step S101, when the sine wave signal Vs and the cosine wave signal Vc are input from the first A / D converter 21 and the second A / D converter 22, the division unit 31 divides these signals. The division result D is output.

In step S102, when the calculation unit 33 receives the division result D, the calculation unit 33 obtains a correction value C corresponding to the division result D with reference to the data table Ta stored in the storage unit 32.
In step S103, after calculating the target value Dt by adding the correction value C to the division result D, the calculation unit 33 obtains the rotation angle θ ′ in the range of “0 to 45 °” based on the target output Dt.

  In step S104, the calculation unit 33 determines which of the eight quadrants at 45 ° intervals the division result D corresponds to. Then, the rotation angle θ ′ is converted into the rotation angle θ according to the corresponding quadrant. Thus, the rotation angle detection device 10 obtains the rotation angle θ of the rotating body using the data table Ta.

  Here, the data size of the data table Ta is determined by the number of data points (address) and the data width of the data to be arranged (the correction value C in this example). The number of data points depends on the resolution of the rotation angle detection device 10. The resolution refers to an ability to indicate how fine an analog signal input to the first A / D converter 21 and the second A / D converter 22 is converted into a digital signal, and uses a bit as a unit. . The number of bits after conversion is the data width. As the number of bits is larger, the digital signal is obtained by finely dividing the analog signal. For example, when the input range of the analog signal is decomposed by 8 bits, the decomposition number is “2 ＾ 8 = 256”, and when the input range is decomposed by 9 bits, the decomposition number is “2 ＾ 9 = 512”. That is, as the number of bits increases by one, the number of decompositions doubles. In the data table Ta of this example, data (correction values C) are arranged corresponding to all the division results D, so that the number of data points (address) is equal to the number of decompositions.

  The data width of the data arranged in the data table Ta depends on the value range of the data. If the target output Dt for the division result D is directly arranged in the data table Ta (in the case of the conventional allocation table), the data range is "0 to 1" corresponding to "0 to 45 degrees" of the rotation angle θ. Range. This is equal to the range “0 to 1” of the division result D. On the other hand, in the case of the present example (in the case of the correction table of the present example), the correction values C are arranged in the data table Ta. Since the range of the correction value C is smaller than the range “0 to 1” of the division result D, the correction value C can be expressed by only the lower few bits of the bits forming the division result D. For example, when the division result D is composed of eight bits, the correction value C is composed of only lower three bits.

  As shown in FIG. 6A, when the target output Dt for the division result D is arranged in the data table Ta (in the case of the conventional allocation table), the data width is equal to the number of bits of the division result D. Therefore, for example, when the resolution is “8 bits”, the data width of the rotation angle θ arranged in the data table Ta is also “8 bits”, and the data size of the data table Ta is “2048 bits”. On the other hand, as shown in FIG. 6B, when the correction values C are arranged in the data table Ta (in the case of the correction table of the present example), the data width is smaller than the division result D. Therefore, for example, when the resolution is “8 bits”, the data width of the correction values C arranged in the data table Ta is “3 bits”, and the data size of the data table Ta is “768 bits”. As described above, when the correction values C are arranged in the data table Ta, the data size can be made smaller than when the target output Dt (or the rotation angle θ) is arranged in the data table Ta. Note that the address of the data table Ta is the same as when the target output Dt (rotation angle θ) is arranged and when the correction value C is arranged, so that the resolution of the rotation angle detection device 10 is ensured.

  In this example, a data table Ta in which a division result D and a correction value C for correcting the division result D to a target output Dt are associated with each other, and an operation of calculating the rotation angle θ of the rotating body using the data table Ta is performed. A part 33 is provided. According to this configuration, when the correction values C are arranged in the data table Ta, the data width can be smaller than when the target output Dt is arranged in the data table Ta. As a result, the data size can be reduced.

<Second embodiment>
Next, a second embodiment of the present invention will be described with reference to FIGS. Note that the second embodiment mainly differs from the first embodiment in that the range of the rotation angle θ ′ is divided into a plurality of regions. Therefore, the same components as those in the first embodiment are denoted by the same reference numerals, detailed description thereof will be omitted, and only different portions will be described in detail.

  FIG. 7 shows an image of a data table (common data table Ta1) in which the correction value C is shared among a plurality of regions R obtained by dividing the division result D within a prescribed range. In the case of this example, the common data table Ta1 is superimposed on the data table before the correction value C is standardized by inverting the region R at a specified position on the index side of the operation value (division result D). One or more regions R are created, and the correction values C are shared in the overlapping regions. In the common data table Ta1 of this example, the correction value C is made common in the overlapping region by inverting at the center position of the rotation angle θ.

  In the case of this example, the region R has four regions of a first region R1, a second region R2, a third region R3, and a fourth region R4 in the range of the rotation angle θ ′, that is, in the range of “0 to 45 °”. Is divided into Here, when the curve of the correction value C in the fourth region R4 is inverted, the curve approximates the curve of the correction value C in the first region R1. When the curve of the correction value C in the third region R3 is inverted, the curve approximates the curve of the correction value C in the second region R2. That is, the range of the correction value C is similar between the first region R1 and the fourth region R4, and the range of the correction value C is similar between the second region R2 and the third region R3.

  In the common data table Ta1, in each region R, the correction value C is shared between the regions set as a set. In the case of this example, the first region R1 and the fourth region R4 are set as a set. That is, the correction value C is shared by the first region R1 and the fourth region R4. The second region R2 and the third region R3 are set as a set. That is, the correction value C is shared by the second region R2 and the third region R3. For example, when the division result D corresponds to the fourth area R4 (third area R3), the arithmetic unit 33 determines the division result so that a part corresponding to the first area R1 (second area R2) in the common data table Ta1 can be referred to. Processing such as inverting D may be performed.

  As shown in FIG. 8, the rotation angle detection device 10 includes an area determination unit 34 that determines which of the areas R the division result D corresponds to. The region determining unit 34 determines which region R corresponds to the size of the division result D.

  The storage unit 32 stores a common data table Ta1 in which the correction values C are shared among a plurality of regions R. Upon receiving the division result D based on the determination result of the area determination unit 34, the calculation unit 33 refers to the common data table Ta1 and specifies a correction value C corresponding to the division result D.

  The rotation angle detection device 10 includes a correction value conversion unit 35 that converts the correction value C shared for each group into an ideal value to be taken in each region using a coefficient set for each region R. . When calculating the correction value C corresponding to the division result D with reference to the common data table Ta1, the correction value converter 35 outputs a correction value C ′ obtained by multiplying the correction value C by a coefficient. The coefficients include a coefficient α set in the first region R1, a coefficient β set in the second region R2, a coefficient γ set in the third region R3, and a coefficient δ set in the fourth region R4. For example, when the area determination unit 34 determines that the division result D corresponds to the first area R1, the correction value conversion unit 35 multiplies the correction value C derived from the common data table Ta1 by the coefficient α to obtain the correction value C. Is output.

  When the correction value C ′ is input from the correction value conversion unit 35, the calculation unit 33 adds the correction value C ′ to the division result D to calculate the rotation angle θ ′ in the range of “0 to 45 °”. Then, the calculation unit 33 converts the rotation angle θ ′ into a rotation angle θ in a range of “0 to 360 °” based on the eight quadrants.

Next, the operation and effect of the rotation angle detection device 10 according to the second embodiment will be described with reference to FIGS.
As shown in FIG. 9, in step S201, the division unit 31 outputs a division result D.

In step S202, the region determination unit 34 determines which of the regions R the division result D corresponds to based on the size of the division result D.
In step S203, the calculation unit 33 refers to the common data table Ta1 according to the region R determined by the region determination unit 34. Then, a correction value C corresponding to the division result D is obtained.

In step S204, when the correction value conversion unit 35 receives the correction value C, the correction value conversion unit 35 multiplies the correction value C by a coefficient corresponding to the region R and outputs a correction value C ′ to the calculation unit 33.
In step S205, the calculation unit 33 adds the correction value C ′ to the division result D to obtain a rotation angle θ ′ in a range of “0 to 45 °”.

In step S206, the calculation unit 33 determines the rotation angle θ ′ in the range of “0 to 360 °” based on the eight quadrants.
As described above, the data size of the common data table Ta1 is determined by the number of data points (addresses) and the data width. Since the common data table Ta1 shares the correction value C between the regions R set as a set, it is not necessary to store a data table of a portion corresponding to the third region R3 and the fourth region R4. The number of data points (addresses) can be reduced. Therefore, the data size can be further reduced than in the first embodiment. At this time, since the regions where the range (curve) of the correction value C is approximated are paired, the correction value C is approximated, so that it is possible to suppress the correction value C from becoming a large erroneous value. However, strictly speaking, even when the range of the correction value C is the same, a difference may occur between different regions R due to a different correlation between the division result D and the correction value C.

  As shown in FIG. 10, for example, when the correction value C is shared by the first region R1 and the fourth region R4, the common data is compared with the ideal correction value for correcting the division result D to the target output Dt. A shift may occur in the correction values C arranged in the table Ta1. The ideal correction value is as shown by the solid line in FIG. For example, in the case of the first region R1, the correction value C deviates from the ideal correction value as shown by a chain line in FIG. Further, for example, in the case of the fourth region R4, the correction value C deviates from the ideal correction value as shown by a two-dot chain line in FIG.

  In the case of the present example, the correction value C is converted to the correction value C ′ using the coefficient α in the first region R1 so that the deviation between the correction value C and the ideal correction value is reduced. Further, in the case of the fourth region R4, the correction value C is converted to the correction value C ′ using the coefficient δ such that the difference between the correction value C and the ideal correction value is reduced. As a result, the calculation unit 33 can calculate the rotation angle θ using the correction value C ′ in which the deviation is reduced, so that the calculation accuracy of the rotation angle θ can be ensured.

  In this example, in the common data table Ta1, in the region R obtained by dividing the division result D in a specified range, the correction value C is shared between the regions R set as a set. According to this configuration, it is not necessary to hold another correction value C for the common region R, and the number of data points (addresses) can be reduced. This contributes to a reduction in data size.

  In this example, the correction value C is shared between the areas where the calculated value (division result D) is inverted at the specified position on the index side. According to this configuration, when the correction value C is shared by different regions R, the region R is inverted and shared by the overlapped regions R, so that the range of the correction value C is likely to be approximated. Therefore, it is easy to suppress the deviation of the correction value C. Thereby, the error of the rotation angle θ caused by the deviation of the correction value C can be suppressed, and this contributes to securing the calculation accuracy of the rotation angle θ.

  In the present example, a correction value conversion unit 35 that corrects the common correction value C with the correction coefficient set for each region R is provided. According to this configuration, the shift of the correction value C can be corrected by the correction value conversion unit 35 when sharing the common data table Ta1 in different regions R. This further contributes to ensuring the calculation accuracy of the rotation angle θ.

This embodiment can be implemented with the following modifications. The present embodiment and the following modifications can be implemented in combination with each other within a technically consistent range.
-In 2nd Embodiment, a coefficient can be set arbitrarily. Further, the correction value C is not limited to being multiplied by a coefficient, and the correction value C can be converted by an arbitrary arithmetic method.

  In the second embodiment, the conversion of the correction value C into the correction value C ′ by the coefficient by the correction value conversion unit 35 can be omitted from the configuration requirements. However, the conversion by the correction value converter 35 is advantageous for ensuring the calculation accuracy of the rotation angle θ.

  In the second embodiment, the division position of the region R and the number of divisions are not particularly limited. For example, the range of “0 to 45 °” may be divided into four equal parts, or the range of the correction value C may be divided so as to make a set equal.

  In the second embodiment, how to set the different regions R as a set is not particularly limited. In short, as long as the correction value C can be shared, the combination of the regions R as a set is arbitrary. However, when the region R is inverted at the specified position on the index side of the calculated value and the regions overlapped with each other are grouped, the range of the correction value C is likely to be approximated, so that the deviation of the correction value C is easily suppressed.

  In the second embodiment, in the case of the fourth region R4 (third region R3), the common correction value C is obtained by referring to the portion corresponding to the first region R1 (second region R2) of the common data table Ta1. Is extracted, but the method of extracting the correction value C is not particularly limited. It is sufficient that the common data table Ta1 can be shared by a plurality of regions R. For example, the common data table Ta1 may be subjected to arithmetic processing such as inverting the arrangement of the common data table Ta1.

  In the second embodiment, the data width of the correction value (see FIG. 6) is a guide and is not limited to this. It can be changed as appropriate according to the purpose of reducing the data size or securing the calculation accuracy of the rotation angle θ.

  In each embodiment, the distribution map in which the correction value C is distributed with respect to the index (for example, the rotation angle θ) of the operation value (division result D) has a substantially parabolic waveform characteristic having a peak as a peak. Not limited.

  In the second embodiment, the specified position for inverting the region R is not limited to the center position of the rotation angle θ that is the index on the horizontal axis in the distribution map of the correction values C. For example, the peak position of the correction value C may be inverted as a specified position according to the waveform characteristics of the distribution map.

  In each embodiment, the division result D is divided into any of eight quadrants based on the magnitude relationship between the sign of the sine wave signal Vs and the cosine wave signal Vc and the absolute value of the sine wave signal Vs and the absolute value of the cosine wave signal Vc. , And applying the range “0 to 45 °” of the data table Ta to one rotation (360 °) can be omitted from the components. However, by expanding the detection range using the eight quadrants, the data size of the data table Ta to be held is reduced, which contributes to a reduction in the data size.

  In each embodiment, the correction values C arranged in the data table Ta and the common data table Ta1 are not limited to those based on the difference between the division result D and the target output Dt. For example, it may be based on the ratio between the division result D and the target output Dt. That is, the correction value C may be any value that corrects the division result D to the target output Dt.

  In each embodiment, the method of correcting the operation value (division result D) to the target value (target output Dt) using the correction value C is not limited to adding the correction value C to the division result D, and And the other arithmetic methods. Further, the numerical value of the correction value C can be changed as appropriate.

  -In each embodiment, the operation value obtained from the output of the detection unit is not limited to the division result D. Any calculation value obtained by calculating the detection signals (sine wave signal Vs and cosine wave signal Vc) of the sensor 11 may be used. Also, the numerical value is not limited to “0” from “0” but can be changed as appropriate.

-In each embodiment, the output of the sensor 11 is not limited to the sine wave signal Vs and the cosine wave signal Vc. It can be changed appropriately according to the specifications of the sensor 11.
In each embodiment, the sensor 11, the first A / D converter 21, the second A / D converter 22, and the microcomputer 20 are not limited to being assembled in the same unit. They may be installed as separate members.

-In each embodiment, the sensor 11 is not limited to a magnetic sensor. For example, various sensors, such as an optical sensor, that changes the output according to the rotation angle of the rotating body can be used.
In each embodiment, the resolution of the rotation angle detection device 10 is not particularly limited. For example, it may be 12 bits or more or 8 bits or less. In addition, the number of data points (addresses) of the correction value C for the resolution is not limited, and may not be the same as the number of decompositions. This can be changed as appropriate according to the specifications. However, by setting the number of data points (address) of the correction value C to be the same as the number of decompositions, the calculation accuracy of the rotation angle θ is secured.

In each embodiment, the detection range of the rotation angle θ is not limited to “0 to 360 °”. In addition, the range of the data table Ta can be changed as appropriate.
In each embodiment, the reference position (zero point) of the rotation of the sensor 11 can be arbitrarily adjusted. The arrangement of the data table Ta (common data table Ta1) can also be adjusted by zero point adjustment.

  In each embodiment, the detection target of the rotation angle detection device 10 is not particularly limited. For example, the present invention is applicable to a rotation angle detection device that detects a rotation mode of a general rotating body such as a steering sensor that detects a rotation angle of a steering.

Next, technical ideas that can be grasped from the above-described embodiment and its modifications will be described below together with their effects.
(A) In the rotation angle detection device, the detection unit outputs a sine wave signal and a cosine wave signal that change with the rotation of the rotator, and the calculated value is the sine wave signal and the cosine wave signal. Taking a value that repeats for each quadrant obtained by dividing one rotation of the rotator into a plurality of quadrants based on the data table, the data table arranges the correction values corresponding to the calculated values in one of the quadrants, The unit determines which of the quadrants the calculated value corresponds to, and applies the rotation angle in the quadrant calculated using the data table to the rotation angle in one rotation of the rotator. According to this configuration, it is not necessary to store the correction values corresponding to the entire range of one rotation of the rotator in the quadrant. This contributes to a reduction in data size.

DESCRIPTION OF SYMBOLS 10 ... rotation angle detection apparatus, 11 ... sensor, 12 ... 1st bridge circuit, 13 ... 2nd bridge circuit, 20 ... microcomputer, 21 ... 1st A / D converter, 22 ... 2nd A / D converter, 31 ... Division unit, 32 storage unit, 33 operation unit, 34 area determination unit, 35 correction value conversion unit, Ta data table, Ta1 common data table.

Claims (4)

A detection unit whose output changes according to the rotation angle of the rotating body,
A data table in which a calculated value of the rotation angle obtained from an output of the detection unit and a correction value for correcting the calculated value to a target value are associated with each other;
A calculation unit for calculating a rotation angle of the rotator using the data table. 2. The rotation angle detection device according to claim 1, wherein in the data table, in each area obtained by dividing the operation value in a prescribed range, the correction value is shared between the areas set as a set. The data table in which the correction values are shared is overlapped with each other by inverting the area at a specified position on the index side of the calculated value in the data table before the correction values are shared. The rotation angle detecting device according to claim 2, wherein one or more regions are created, and the correction values are shared in the overlapping regions. The rotation according to claim 2, further comprising a correction value conversion unit configured to convert the common correction value for each set into an ideal value to be taken in each region using a coefficient set for each region. Angle detector.