CN107860404B - Rotary encoder and absolute angle position detection method for rotary encoder - Google Patents

Rotary encoder and absolute angle position detection method for rotary encoder Download PDF

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Publication number
CN107860404B
CN107860404B CN201710851546.1A CN201710851546A CN107860404B CN 107860404 B CN107860404 B CN 107860404B CN 201710851546 A CN201710851546 A CN 201710851546A CN 107860404 B CN107860404 B CN 107860404B
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angle data
absolute angle
phase
absolute
correction
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CN107860404A (en
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奥村宏克
斋藤丰
上甲均
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Nidec Instruments Corp
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Nidec Sankyo Corp
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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01D—MEASURING NOT SPECIALLY ADAPTED FOR A SPECIFIC VARIABLE; ARRANGEMENTS FOR MEASURING TWO OR MORE VARIABLES NOT COVERED IN A SINGLE OTHER SUBCLASS; TARIFF METERING APPARATUS; MEASURING OR TESTING NOT OTHERWISE PROVIDED FOR
    • G01D18/00—Testing or calibrating apparatus or arrangements provided for in groups G01D1/00 - G01D15/00
    • G01D18/002—Automatic recalibration
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01D—MEASURING NOT SPECIALLY ADAPTED FOR A SPECIFIC VARIABLE; ARRANGEMENTS FOR MEASURING TWO OR MORE VARIABLES NOT COVERED IN A SINGLE OTHER SUBCLASS; TARIFF METERING APPARATUS; MEASURING OR TESTING NOT OTHERWISE PROVIDED FOR
    • G01D5/00—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable
    • G01D5/12—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable using electric or magnetic means
    • G01D5/244—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable using electric or magnetic means influencing characteristics of pulses or pulse trains; generating pulses or pulse trains
    • G01D5/249—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable using electric or magnetic means influencing characteristics of pulses or pulse trains; generating pulses or pulse trains using pulse code
    • G01D5/2497—Absolute encoders
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01D—MEASURING NOT SPECIALLY ADAPTED FOR A SPECIFIC VARIABLE; ARRANGEMENTS FOR MEASURING TWO OR MORE VARIABLES NOT COVERED IN A SINGLE OTHER SUBCLASS; TARIFF METERING APPARATUS; MEASURING OR TESTING NOT OTHERWISE PROVIDED FOR
    • G01D5/00—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable
    • G01D5/12—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable using electric or magnetic means
    • G01D5/14—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable using electric or magnetic means influencing the magnitude of a current or voltage
    • G01D5/16—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable using electric or magnetic means influencing the magnitude of a current or voltage by varying resistance

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  • General Physics & Mathematics (AREA)
  • Transmission And Conversion Of Sensor Element Output (AREA)

Abstract

The invention provides an absolute angle position detection method of a rotary encoder, which can restrain the reduction of detection precision caused by relative position deviation between a first sensing part and a second sensing part. As a pre-correction process of the absolute angle position detection operation, first absolute angle data (abs-1) is acquired by a first sensor unit (1a) of a rotary encoder (1), incremental angle data (INC) is acquired by a second sensor unit (1b), and a phase difference (Δ p) between the first absolute angle data and the incremental angle data is acquired. Then, the phase of the first absolute angle data is corrected by the phase difference (Δ p), and phase-corrected first absolute angle data (abs-1p) is calculated. Then, a correction value (Δ q) is obtained based on the difference between the incremental signal conversion absolute angle data (INC-abs) obtained by converting the incremental angle data into absolute angle data of one rotation and the phase correction first absolute angle data (abs-1p), and the phase correction first absolute angle data (abs-1p) is corrected by the correction value (Δ q), thereby obtaining error correction first absolute angle data (abs-1 c).

Description

Rotary encoder and absolute angle position detection method for rotary encoder
Technical Field
The present invention relates to a rotary encoder for detecting an instantaneous absolute angular position of a rotating body and an absolute angular position detection method for the rotary encoder.
Background
Patent document 1 describes a rotary encoder that detects rotation of a rotating body with respect to a fixed body. The rotary encoder of this document includes a first sensor unit and a second sensor unit, and detects an instantaneous absolute angular position of a rotating body based on a detection result of the first sensor unit and a detection result of the second sensor unit. The first sensing unit includes: the Hall sensor includes a first magnet in which N-poles and S-poles are arranged one by one, a first magnetoresistive element arranged to face the first magnet, a first Hall element arranged to face the first magnet, and a second Hall element arranged to face the first magnet and arranged at a position that is offset by a mechanical angle of 90DEG from the first Hall element about a rotation center axis. The second sensor unit includes a second magnet having a plurality of pairs of magnetic poles arranged around the rotation center axis, and a second magnetoresistive element facing the second magnet. The rotary encoder determines an instantaneous angular position of the rotating body based on absolute angle data of one rotation cycle obtained by the first sensor unit and incremental angle data of N rotation cycles obtained by the second sensor unit.
Documents of the prior art
Patent document
Patent document 1: japanese patent No. 5666886
Disclosure of Invention
Technical problem to be solved by the invention
In the rotary encoder including the first sensor unit and the second sensor unit as in patent document 1, there is a case where a relative positional shift occurs between the first sensor unit and the second sensor unit. If the position of each sensor unit is shifted, a phase deviation or an error occurs between the absolute angle data of the first sensor unit and the incremental angle data of the second sensor unit, which leads to a problem of lowering the detection accuracy.
In view of the above-described problems, it is an object of the present invention to provide a rotary encoder and an absolute angular position detection method for a rotary encoder, which can suppress a decrease in detection accuracy due to a relative positional shift between a first sensor unit and a stacked sensor unit even when an absolute angular position of a rotating body is detected based on a detection result of the first sensor unit and a detection result of a second sensor unit.
Technical scheme for solving technical problem
In order to solve the above problem, a rotary encoder according to the present invention includes a first sensor unit that acquires first absolute angle data of 1 cycle of rotation and a second sensor unit that acquires incremental angle data of N cycles of rotation, where N is a positive integer of 2 or more, and detects an absolute angle position based on a first detection result of the first sensor unit and a second detection result of the second sensor unit, the rotary encoder including: a phase difference acquiring unit that acquires a phase difference between the first absolute angle data and the incremental angle data; a conversion absolute angle data calculation unit which converts the incremental angle data of N cycles into absolute angle data of one rotation and calculates incremental signal conversion absolute angle data; a first phase correction unit that corrects the first absolute angle data based on the phase difference and generates phase-corrected first absolute angle data in which a phase of the first absolute angle data matches a phase of the incremental signal conversion absolute angle data; a correction value obtaining section for obtaining a correction value based on a difference between the incremental signal conversion absolute angle data and the phase correction first absolute angle data; a relative error correction unit that corrects the phase-corrected first absolute diagonal data by the correction value to generate error-corrected first absolute diagonal data; and an absolute angle acquisition unit that acquires an absolute angle based on the first detection result, the second detection result, the phase difference, the error correction first absolute angle data, and the incremental angle data.
In the present invention, the instantaneous absolute angle position of the rotating body is detected based on the first detection result (first absolute angle data of 1 cycle of rotation) of the first sensor unit and the second detection result (incremental angle data of N cycles of rotation) of the second sensor unit. Therefore, the instantaneous absolute angular position of the rotating body can be detected with high resolution. In addition, in the present invention, the phase difference between the first absolute angle data and the incremental angle data is acquired, the phase corrected first absolute angle data in which the phase of the first absolute angle data is made to coincide with the phase of the incremental angle data is calculated, the correction value is obtained based on the difference between the incremental signal converted absolute angle data obtained by converting the incremental angle data into the absolute angle data of one rotation and the phase corrected first absolute angle data, and the phase corrected first absolute angle data is corrected by the correction value, so that the error corrected first absolute angle data is obtained. Here, the error correction first absolute angle data is data in which the first absolute angle data is attached with a relative error between the first absolute angle data and the increment angle data of N cycles. Therefore, the error corrects the relative error between the first absolute angle data and the incremental angle data or disappears or is suppressed. Thus, when the absolute angle position is determined by correcting the first absolute angle data and the incremental angle data based on the error, it is possible to suppress a decrease in detection accuracy due to a relative positional shift between the first sensing unit and the second sensing unit.
In the present invention, in order to acquire error-corrected first absolute angle data, the correction value acquisition unit may acquire the correction value by subtracting the phase-corrected first absolute angle data from the incremental signal conversion absolute angle data, and the relative error correction unit may acquire the error-corrected first absolute angle data by adding the phase-corrected first absolute angle data to the correction value.
In the present invention, in order to acquire error-corrected first absolute angle data, the correction value acquisition unit may acquire the correction value by subtracting the incremental signal conversion absolute angle data from the phase-corrected first absolute angle data, and the relative error correction unit may acquire the correction value by subtracting the correction value from the phase-corrected first absolute angle data.
In the present invention, it is preferable that the correction value acquisition unit acquires the correction values corresponding to a plurality of angular positions in 1 cycle of rotation, stores and stores in the storage unit the correction values acquired at the angular positions in association with the respective angular positions, and the relative error correction unit calculates an intermediate correction value of an intermediate angular position between 2 adjacent angular positions based on the correction values acquired at the respective 2 angular positions, and corrects the phase-corrected first absolute angular data using the correction value and the intermediate correction value stored and stored in the storage unit as the correction values. Thus, the phase corrected first absolute angle data can be corrected by the correction value stored and held in the storage unit and the intermediate correction value interpolated between the correction values stored and held in the storage unit, and therefore the error between the error corrected first absolute angle data and the incremental angle data can be further suppressed. Further, since the intermediate correction value can be obtained by calculation, the capacity for storing and holding the correction value can be suppressed.
In the present invention, it is preferable that the absolute angle acquisition unit includes: a second absolute angle data generation unit that interpolates and divides the error correction first absolute angle data into N pieces to generate a second absolute angle; a phase comparison unit that compares a phase of the second absolute angle data with a phase of the incremental angle data; a phase correction unit that corrects the second absolute angle data when the phase of the second absolute angle data is different from the phase of the incremental angle data as a result of the comparison by the phase comparison unit; and an angle position determination unit configured to determine an absolute angle position of the rotating body based on a phase correction first detection result obtained by correcting the first detection result by the phase difference, the second detection result, the second absolute angle data, and the incremental angle data. Thus, even when the error correction first absolute angle data includes an error such as a phase shift from the incremental angle data, the error can be suppressed by the correction. Further, since the absolute angular position is determined by correcting the first detection result by the phase difference using the phase difference phase corrected first detection result obtained by correcting the first detection result of the first sensor unit by the phase difference, it is possible to further suppress a decrease in detection accuracy due to a relative positional shift between the first sensor unit and the second sensor unit, or the like.
In the present invention, the first sensor unit may include: first magnets each having an N pole and an S pole arranged one by one around a rotation center axis; a first magnetoresistive element opposing the first magnet in a rotational center axis direction; a first hall element opposed to the first magnet; a second hall element disposed opposite to the first magnet and at a position shifted from the first hall element by a mechanical angle of 90 ° around a rotation center axis, the second sensor unit including: a second magnet having a plurality of pairs of magnetic poles arranged around the rotation center axis; and a second magnetoresistive element opposing the second magnet.
The present invention also relates to an absolute angle position detection method for a rotary encoder including a first sensor unit and a second sensor unit, the first sensor unit acquiring first absolute angle data of 1 cycle of rotation, and the second sensor unit acquiring incremental angle data of N cycles of rotation, where N is a positive integer of 2 or more, the rotary encoder detecting an absolute angle position based on a first detection result of the first sensor unit and a second detection result of the second sensor unit, the absolute angle position detection method including: a phase difference obtaining step of obtaining a phase difference between the first absolute angle data and the incremental angle data; a conversion absolute angle data calculation step of converting the increment angle data of N cycles into absolute angle data of one rotation to calculate incremental signal conversion absolute angle data; a first phase correction step of correcting the first absolute angle data based on the phase difference and generating phase-corrected first absolute angle data in which a phase of the first absolute angle data coincides with a phase of the incremental signal conversion absolute angle data; a correction value obtaining step of obtaining a correction value based on a difference between the incremental signal conversion absolute angle data and the phase correction first absolute angle data; a relative error correction step of correcting the phase corrected first absolute angle data by the correction value to generate error corrected first absolute angle data; and an absolute angle acquisition step of acquiring an absolute angle based on the first detection result, the second detection result, the phase difference, the error correction first absolute angle data, and the incremental angle data.
In the present invention, the instantaneous absolute angle position of the rotating body is detected based on the first detection result (first absolute angle data of 1 cycle of rotation) of the first sensor unit and the second detection result (incremental angle data of N cycles of rotation) of the second sensor unit. Therefore, the instantaneous absolute angular position of the rotating body can be detected with high resolution. In addition, in the present invention, the phase difference between the first absolute angle data and the incremental angle data is acquired, the phase corrected first absolute angle data in which the phase of the first absolute angle data is made to coincide with the phase of the incremental angle data is calculated, the correction value is obtained based on the difference between the incremental signal converted absolute angle data obtained by converting the incremental angle data into the absolute angle data of one rotation and the phase corrected first absolute angle data, and the phase corrected first absolute angle data is corrected by the correction value, so that the error corrected first absolute angle data is obtained. Here, the error correction first absolute angle data is data in which the first absolute angle data is attached with a relative error between the first absolute angle data and the increment angle data of N cycles. Therefore, the error corrects the relative error between the first absolute angle data and the incremental angle data or disappears or is suppressed. Thus, when the absolute angular position is determined by correcting the first absolute angular data and the incremental angular data based on the error, it is possible to suppress a decrease in detection accuracy due to a relative displacement between the first sensing unit and the second sensing unit.
In the present invention, in order to acquire error-corrected first absolute angle data, the correction value acquisition step may acquire the correction value by subtracting the phase-corrected first absolute angle data from the incremental signal conversion absolute angle data, and the relative error correction step may acquire the error-corrected first absolute angle data by adding the phase-corrected first absolute angle data to the correction value.
In the present invention, in order to acquire error-corrected first absolute angle data, the correction value acquisition step may acquire the correction value by subtracting the incremental signal conversion absolute angle data from the phase-corrected first absolute angle data, and the relative error correction step may acquire the error-corrected first absolute angle data by subtracting the correction value from the phase-corrected first absolute angle data.
In the present invention, it is preferable that the correction value acquisition step acquires the correction values corresponding to a plurality of angular positions in 1 cycle of rotation, stores and stores the correction values acquired at the angular positions in association with the respective angular positions in the storage unit, and the relative error correction step calculates an intermediate correction value of an intermediate angular position between 2 adjacent angular positions based on the correction values acquired at the respective 2 angular positions, and corrects the phase-corrected first absolute angular data using the correction value and the intermediate correction value stored and stored in the storage unit as the correction values. Thus, the phase corrected first absolute angle data can be corrected by the correction value stored and held in the storage unit and the intermediate correction value interpolated between the correction values stored and held in the storage unit, and therefore the error between the error corrected first absolute angle data and the incremental angle data can be further suppressed. Further, since the intermediate correction value can be obtained by calculation, the capacity for storing and holding the correction value can be suppressed.
In the present invention, the absolute angle obtaining step includes: a second absolute angle data generating step of interpolating and dividing the error correction first absolute angle data into N pieces to generate a second absolute angle; a phase comparison step of comparing the phase of the second absolute angle data with the phase of the incremental angle data; a second phase correction step of correcting the second absolute angle data when the phase of the second absolute angle data is deviated from the phase of the incremental angle data as a result of the comparison in the phase comparison step; and an angle position determining step of determining an absolute angle position of the rotating body based on the phase corrected first detection result obtained by correcting the first detection result by the phase difference, the second detection result, the second absolute angle data, and the incremental angle data. Thus, even when the error correction first absolute angle data includes an error such as a phase shift from the incremental angle data, the error can be suppressed by the correction. In addition, since the absolute angular position is determined by correcting the first detection result by the phase difference using the phase difference phase corrected first detection result obtained by correcting the first detection result of the first sensor unit by the phase difference, it is possible to further suppress a decrease in detection accuracy due to a relative displacement between the first sensor unit and the second sensor unit.
In the present invention, it is preferable that the first sensor unit includes: first magnets each having an N pole and an S pole arranged one by one around a rotation center axis; a first magnetoresistive element opposing the first magnet in a rotational center axis direction; a first hall element opposed to the first magnet; a second hall element disposed opposite to the first magnet and at a position shifted from the first hall element by a mechanical angle of 90 ° around a rotation center axis, the second sensor unit including: a second magnet having a plurality of pairs of magnetic poles arranged around the rotation center axis; and a second magnetoresistive element opposing the second magnet.
Effects of the invention
In the present invention, error correction first absolute angle data in which a relative error between first absolute angle data from a first sensor unit and incremental angle data from a second sensor unit is added to the first absolute angle data is acquired, and an absolute angle position is detected based on the error correction first absolute angle data and the incremental angle data. Here, the error corrects the relative error between the first absolute angle data and the incremental angle data, between the first absolute angle data and the incremental angle data of N cycles, or eliminates or suppresses. Therefore, when the absolute angle position is acquired by correcting the first absolute angle data and the incremental angle data based on the error, it is possible to suppress a decrease in detection accuracy due to a relative positional deviation or the like.
Drawings
Fig. 1 is an explanatory diagram showing an appearance and the like of a rotary encoder to which the present invention is applied.
Fig. 2 is a side view showing a part of a fixed body of the rotary encoder of fig. 1 cut away.
Fig. 3 is an explanatory diagram showing the configuration of a sensor unit and the like of the rotary encoder.
Fig. 4 is an explanatory diagram illustrating the principle of detecting the angular position of the rotary encoder.
Fig. 5 is an explanatory diagram showing a basic configuration of an angular position determining method of the rotary encoder.
Fig. 6 is an explanatory diagram of phase difference between the first absolute angle data and the incremental angle data and phase correction of the first absolute angle data.
Fig. 7 is an explanatory diagram of conversion of absolute angle data.
Fig. 8 is an explanatory diagram of the correction value.
Fig. 9 is an explanatory diagram of error correction first absolute angle data.
Fig. 10 is an explanatory diagram showing a specific configuration of the angular position determining method of the rotary encoder.
Fig. 11 is an explanatory diagram in the case where the phase of the second absolute angle data is advanced.
Fig. 12 is an explanatory diagram in the case of phase delay of the second absolute angle data.
Fig. 13 is a flowchart of an absolute angle position detection operation for detecting an absolute angle position.
Detailed Description
Next, an embodiment of a rotary encoder to which the present invention is applied will be described with reference to the drawings. In the following description, a rotary encoder will be described mainly on a magneto-electric rotary encoder in which a sensor portion is composed of a magnet and a magnetic sensor element (a magnetoresistive element or a hall element). In this case, the magnetic induction element may be provided on the fixed body and the magnetic induction element may be provided on the rotating body, or the magnetic induction element may be provided on the fixed body and the magnet may be provided on the rotating body. In the drawings referred to below, the structures of the magnet, the magnetic induction element, and the like are schematically shown, and the number of magnetic poles of the second magnet is reduced. The structure of the magnetoresistive patterns of the magnetoresistive elements (magnetosensitive elements) is also schematically illustrated with their positions shifted from each other.
(Overall Structure)
Fig. 1 is an explanatory diagram showing an appearance and the like of a rotary encoder to which the present invention is applied. Fig. 1(a) is a perspective view of the rotary encoder as viewed from one side in the rotation axis direction and from an oblique direction, and fig. 1(b) is a plan view of the rotary encoder as viewed from one side in the rotation axis direction. Fig. 2 is a side view showing a part of a fixed body of a rotary encoder to which the present invention is applied, in a cut-away manner.
The rotary encoder 1 is a device that magnetically detects rotation of the rotating body 2 about the rotation axis with respect to the fixed body 1. The fixed body 10 is fixed to a frame or the like of the motor device, and the rotating body 2 is used in a state of being connected to a rotation output shaft or the like of the motor device. As shown in fig. 1 and 2, the fixing body 10 includes a sensor substrate 15 and a plurality of support members 11 for supporting the sensor substrate 15. In this example, the support member 11 is composed of a base 12 having a bottom plate 121 formed with a circular opening 122, and a sensor support plate 13 fixed to the base 12.
The sensor support plate 13 is fixed to a substantially cylindrical body portion 123 of the base 12, which projects from an edge portion of the opening 122 in the first direction L1 of the rotation center axis direction L, by screws 191, 192 or the like. A plurality of terminals 16 are provided to project from the sensor support plate 13 in a first direction L1 in the rotation center axis direction L. The body 123 has a projection 124, a hole 125, and the like formed on an end surface thereof in the first direction L1 in the rotation center axis direction L, and the sensor board 15 is fixed to the body 123 by a screw 193 and the like using the hole 125 and the like. In this case, the sensor substrate 15 is fixed with high accuracy in a state of being positioned at a predetermined position by the projection 124 and the like. The sensor substrate 15 is provided with a connector 17 on a surface thereof in a first direction L1 of the rotation center axis direction L. The rotor 2 is a cylindrical member disposed inside the body 123, and a rotation output shaft (not shown) of a motor is connected to the inside thereof by means of engagement or the like. Thereby, the rotary body 2 can rotate about the rotation axis.
(layout of magnet, magnetic induction element, etc.)
Fig. 3 is an explanatory diagram showing the configuration of a sensor unit and the like of the rotary encoder 1 to which the present invention is applied. In fig. 3, the data processing unit 90 includes a CPU or the like that operates based on a program stored in advance. The structure of the data processing unit 90 is shown as a functional block diagram.
The first sensor unit 1a includes a first magnet 20 on the rotor 2 side. The first magnet 20 includes a magnetized surface 21 in which N-pole and S-pole are magnetized in a pole-by-pole manner in the circumferential direction. The magnetized surface 21 faces a first direction L1 of the rotation center axis direction L. The first sensor unit 1a includes, on the fixed body 10 side: a first magnetoresistive element 40 facing the magnetized surface 21 of the first magnet 20 in a first direction L1 of the rotation center axis direction L; a first hall element 51 facing the magnetized surface 21 of the first magnet 20 in a first direction L1 of the rotation center axis direction L; and a second hall element 52 that is opposed to the magnetized surface 21 of the first magnet 20 in a first direction L1 of the rotation center axis direction L and is disposed at a position shifted by a mechanical angle of 90 ° from the first hall element 51 about the rotation axis.
The second sensor unit 1b has a second magnet 30 on the rotor 2 side. The second magnet has an annular magnetized surface 31 having N-poles and S-poles alternately magnetized in the circumferential direction at a position radially outward from the first magnet 20 to form a plurality of magnetic poles. The magnetized surface 31 faces a first direction L1 of the rotation center axis direction L. In this example, on the magnetized surface 31 of the second magnet 30, a plurality of slots 310, in which N poles and S poles are alternately magnetized in a multi-pole manner in the circumferential direction, are arranged in the radial direction. In this example, the gullets 310 form 2 rows. In this example, when N is a positive integer, N poles and S poles of the second magnet 30 form N pairs. In this example, N is, for example, 128. The positions of the N pole and the S pole are shifted in the circumferential direction between the 2 tooth grooves 310, and in this example, the N pole and the S pole are shifted by one pole in the circumferential direction between the 2 tooth grooves 310. The second sensor unit 1b includes, on the fixed body 10 side, a second magnetoresistive element 60 facing the magnetized surface 31 of the second magnet 30 in the first direction L1 of the rotation center axis direction L.
The first magnet 20 and the second magnet 30 rotate integrally with the rotating body 2 about the rotation axis. The first magnet 20 is formed of a permanent magnet having a disk shape. The second magnet 30 is cylindrical and is disposed radially outward of the first magnet 20. The first magnet 20 and the second magnet 30 are formed of bonded magnets or the like.
The first magnetoresistive element 40 is a first magnetoresistive element including an a-phase (SIN) magnetoresistive pattern and a B-phase (COS) magnetoresistive pattern that are 90 ° out of phase with respect to the phase of the first magnet 20. In the first magnetoresistive element 40 described above, the a-phase magnetoresistive pattern includes a + a-phase (SIN +) magnetoresistive pattern 43 and a-phase (SIN-) magnetoresistive pattern 41 that perform movement detection of the rotating body 2 with a phase difference of 180 °. The B-phase magnetoresistive pattern includes a + B-phase (COS +) magnetoresistive pattern 44 and a-B-phase (COS-) magnetoresistive pattern 42 having a phase difference of 180 ° for performing movement detection of the rotating body 2. Here, the + a-phase magnetoresistive pattern 43 and the-a-phase magnetoresistive pattern 41 constitute a bridge circuit, and the + b-phase magnetoresistive pattern 44 and the-b-phase magnetoresistive pattern 42 also constitute a bridge circuit in the same manner as the + a-phase magnetoresistive pattern 43 and the-a-phase magnetoresistive pattern 41.
The second magnetoresistive element 60 includes an a-phase (SIN) magnetoresistive pattern and a B-phase (COS) magnetoresistive pattern that are 90 ° out of phase with respect to the phase of the second magnet 30. In the second magnetoresistive element 60, the a-phase magnetoresistive pattern includes a + a-phase (SIN +) magnetoresistive pattern 64 and a-phase (SIN-) magnetoresistive pattern 62 that have a phase difference of 180 ° and detect movement of the rotating body 2. The B-phase magnetoresistive pattern includes a + B-phase (COS +) magnetoresistive pattern 63 and a-B-phase (COS-) magnetoresistive pattern 61 that perform movement detection of the rotating body 2 with a phase difference of 180 °. Here, the + a-phase magnetoresistive pattern 64 and the-a-phase magnetoresistive pattern 62 form a bridge circuit in the same manner as the first magnetoresistive element 40, and the + b-phase magnetoresistive pattern 63 and the-b-phase magnetoresistive pattern 61 form a bridge circuit in the same manner as the + a-phase magnetoresistive pattern 64 and the-a-phase magnetoresistive pattern 62.
In this example, the first magnetoresistive element 40, the first hall element 51, the second hall element 52, and the second magnetoresistive element 60 are all provided on the first surface 151 of the sensor substrate 15 in the second direction L2 of the rotation center axis direction L. On a second surface 152 on the opposite side of the first surface 151 of the sensor substrate 15, a first amplifier 91 electrically connected to the first magnetoresistive element 40 via a through hole (not shown) penetrating the sensor substrate 15 is provided at a position overlapping the first magnetoresistive element 40 in a plan view. The second amplifier 92 electrically connected to the second magnetoresistive element 60 through a through hole penetrating the sensor substrate 15 is provided on the second surface 152 at a position overlapping the second magnetoresistive element 60 in a plan view. The first hall element 51 and the second hall element 52 are electrically connected to the first amplifier 91 via a through hole penetrating the sensor substrate 15.
(detection principle)
Fig. 4 is an explanatory diagram illustrating a detection principle of the rotary encoder 1 to which the present invention is applied. Fig. 4(a) is an explanatory diagram of signals and the like output from the magnetoresistive element 4, and fig. 4(b) is an explanatory diagram showing a relationship between the signals shown in fig. 4(a) and the angular position (electrical angle) of the rotating body 2. Fig. 5 is an explanatory diagram showing a basic configuration of an angular position determining method of the rotary encoder.
As shown in fig. 3, in the rotary encoder 1 of the present example, the outputs of the first magnetoresistive element 40, the first hall element 51, the second hall element 52, and the second magnetoresistive element 60 are output to the data processing unit 90 via the first amplifier 91, the second amplifier 92, and the a-D converters 93a, 93b, and 94. The data processing unit 90 obtains the absolute angular position of the rotating body 2 with respect to the fixed body 10 based on the outputs of the first magnetoresistive element 40, the first hall element 51, the second hall element 52, and the second magnetoresistive element 60.
More specifically, in the rotary encoder 1, when the rotor 2 rotates once, the first magnet 20 also rotates once, and thus the sinusoidal signals sin and cos of 2 cycles as shown in fig. 4(a) are output from the first magnetoresistive element 40 of the first sensor unit 1 a. Thus, as shown in fig. 4(b), the data processing unit 90 obtains θ ═ tan from the sine wave signals sin and cos-1(sin/cos), the angular position θ of the rotating body 2 can be obtained. In this example, the first sensor unit 1a has the first hall element 51 and the second hall element 52 arranged at positions shifted by 90 ° when viewed from the center of the first magnet 20. Therefore, since it is possible to know which section of the sine wave signals sin and cos the current position is in, the absolute angular position of the rotating body 2 can be known.
In the rotary encoder 1 of the present example, the second sensor unit 1b uses the second magnet 30, and the second magnet 30 has the annular magnetized surface 31 in which the N-pole and the S-pole are alternately magnetized in the circumferential direction to form a plurality of pairs of magnetic poles, and outputs the sine wave signals sin and cos of 2 cycles from the second magnetoresistive element 60 facing the second magnet 30 every time the rotating body 2 rotates by one cycle of the magnetic poles of the second magnet 30. Therefore, the sine wave signals sin and cos output from the second magnetoresistive element 60 may be obtained by obtaining θ tan from the sine wave signals sin and cos, as shown in fig. 4(b)-1(sin/cos), the angular position θ of the rotor 2 within an angle corresponding to 1 cycle of the magnetic poles of the second magnet 30 can be obtained.
Therefore, in this example, the instantaneous angular position of the rotating body 2 is detected based on the first absolute angle data abs-1 (see fig. 5 a) of 1 cycle of rotation, which is the first detection result from the first sensor unit 1a, and the incremental angle data INC (see fig. 5 b) of N cycles of rotation, which is the second detection result from the second sensor unit 1 b. Accordingly, even when the resolution of the first absolute angle data abs-1 is low, high-resolution absolute angle data can be obtained.
In the case of the above detection method, in the rotary encoder 1 of the present example, a phase shift occurs between the first absolute angle data abs-1 (see fig. 5(a)) from the first sensor unit 1a and the incremental angle data INC (see fig. 5(b)) having N cycles of rotation from the second sensor unit 1b due to the relative positional shift between the first sensor unit 1a and the second sensor unit 1b, a characteristic error of a member constituting the first sensor unit 1a and the second sensor unit 1b, a sampling time difference between the first sensor unit 1a and the second sensor unit 1b, and the like. Further, the deviation of the first sensor unit 1a from the rotation axis, the deviation of the second sensor unit 1b from the rotation axis, the characteristics of the first sensor unit 1a, and the characteristics of the second sensor unit 1b cause errors in the outputs of the sensor units 1a and 1b with respect to the actual values (angular positions). Here, when a relative error including a phase deviation occurs between the first absolute angle data abs-1 and the incremental angle data INC, the detection accuracy is degraded.
Therefore, in this example, to detect the absolute angular position, the following pre-correction step is first performed: a phase difference Deltap between the first absolute angle data abs-1 and the incremental angle data INC is acquired, and first absolute angle data abs-1c corrected by suppressing or eliminating a relative error in the phase difference and the phase difference Deltap generated between the first absolute angle data abs-1 and the incremental angle data INC is acquired.
Then, the following absolute angle acquisition steps are carried out: the absolute angular position is acquired based on the first detection result, which is the instantaneous first absolute angle data abs-1 output from the first sensor unit 1a, the second detection result, which is the instantaneous incremental angle data INC output from the second sensor unit 1b, the phase difference Δ p acquired in the pre-correction step, the error-corrected first absolute angle data abs-1c, and the incremental angle data INC.
(control System)
Fig. 6 is an explanatory diagram of the phase difference between the first absolute angle data abs-1 and the incremental angle data INC and the phase-corrected first absolute angle data abs-1 p. Fig. 7 is an explanatory diagram of conversion of absolute angle data. Fig. 8 is an explanatory diagram of the correction value. Fig. 9 is an explanatory diagram of the error correction first absolute angle data abs-1 c. Fig. 10 is an explanatory diagram showing a basic configuration of an angular position determining method of the rotary encoder. In fig. 10, the periods of the second absolute angle data abs-2 are denoted by reference numerals 1, 2, … …, N-1, N +1, … …, N indicating the periods of the actual angular positions, and the periods of the incremental angle data INC are denoted by reference numerals 1, 2, … …, m-1, m +1, … …, N indicating the periods of the actual angular positions. Fig. 11 is an explanatory diagram of correction in the case where the phase of the second absolute angle data is advanced in the rotary encoder. Fig. 12 is an explanatory diagram of correction in the case where the phase of the second absolute angle data is delayed in the rotary encoder.
As shown in fig. 3, the data processing unit 90 includes a pre-correction processing unit 100 that performs a pre-correction step and an absolute angle acquisition unit 101 that performs an absolute angle acquisition step.
(Pre-correction processing section)
The pre-correction processing unit 100 includes a memory (storage unit) 102, a phase difference acquisition unit 103, a converted absolute angle data calculation unit 104, a first phase correction unit 105, a correction value acquisition unit 106, and a relative error correction unit 107.
The phase difference acquisition unit 103 acquires the phase difference Δ p between the first absolute angle data abs-1 from the first sensor unit 1a and the incremental angle data INC from the second sensor unit 1 b. That is, as shown in fig. 6(a) and 6(b), the phase difference acquiring unit 103 acquires, as the phase difference Δ p, an angle difference between a point at the angular position 0 ° of the first absolute angle data abs-1 from the first sensor unit 1a and a point at the angular position 0 ° of the incremental angle data INC closest to the point, on the premise that a phase difference occurs between the first absolute angle data abs-1 from the first sensor unit 1a, which has a period of 1 rotation, and the incremental angle data INC, which has a period of N rotation, from the second sensor unit 1 b. The ideal first absolute angle data abs-1 is the straight-line data as shown in fig. 5 (a). However, the first absolute angle data abs-1 from the first sensor unit 1a is deviated from the ideal data by an error contained therein, as shown in fig. 6(a), for example. The ideal incremental angle data INC is a straight line data as shown in fig. 5 (b). However, the incremental angle data INC from the second sensor unit 1b is deviated from the ideal data by an error contained therein, as shown in fig. 6(b), for example.
As shown in fig. 7, the converted absolute angle data calculation unit 104 converts the N-cycle incremental angle data INC (see fig. 6(b) and 7(a)) from the second sensor unit 1b into 1-cycle incremental signal converted absolute angle data INC-abs (see fig. 7 (b)). That is, the converted absolute angle data calculation unit 104 sequentially accumulates the incremental angle data INC from the point of the angular position 0 ° of the incremental angle data INC closest to the point of the angular position 0 ° of the first absolute angle data abs-1, and finally accumulates the incremental angle data INC of the nth cycle, thereby calculating absolute angle data corresponding to the first absolute angle data with 1 cycle of rotation (incremental signal converted absolute angle data INC-abs).
The first phase correction unit 105 corrects the first absolute angle data based on the phase difference Δ p acquired by the phase difference acquisition unit 103, and generates phase-corrected first absolute angle data abs-1p in which the phase of the first absolute angle data matches the phase of the incremental signal conversion absolute angle data INC-abs. That is, as shown in fig. 6(c), the first phase correction unit 105 generates phase-corrected first absolute angle data abs-1p in which the phase of the first absolute angle data is compensated by the phase difference Δ p. Thus, the angular position 0 ° of the phase correction first absolute angle data abs-1p coincides with the angular position 0 ° of the incremental signal conversion absolute angle data INC-abs.
The correction value acquisition unit 106 acquires a correction value Δ q based on the difference between the incremental signal conversion absolute angle data INC-abs and the phase correction first absolute angle data abs-1 p. In this example, the correction value acquisition unit 106 subtracts the phase correction first absolute angle data abs-1p shown in fig. 8(b) from the incremental signal conversion absolute angle data INC-abs shown in fig. 8(a) to acquire the correction value Δ q 1. The correction value Δ q1 shown in fig. 8(c) is a relative error component of the incremental signal conversion absolute angle data INC-abs and the phase correction first absolute angle data abs-1 p.
Here, the correction value acquisition unit 106 acquires the first correction value Δ q1 for a plurality of angular positions in 1 cycle of rotation as the correction value Δ q 1. The correction value acquisition unit 106 stores the angular position and the first correction value Δ q1 in a table format and stores the same in the memory 102, and in this example, the plurality of angular positions at which the correction value Δ q1 is acquired are each divided at equal intervals by one rotation by the number of pole pairs N of the second magnet 30. The plurality of angular positions at which the correction value Δ q1 is obtained may be each angular position obtained by dividing one rotation by a number 2 times the number of pole pairs of the second magnet 30 at equal intervals.
The relative error correction unit 107 refers to the memory 102, and calculates an intermediate correction value Δ q2 for an intermediate angular position between 2 angular positions based on the correction values Δ q1 acquired at the respective adjacent 2 angular positions. In this example, the intermediate angular position is an angular position at the center of the adjacent 2 angular positions, and the correction value acquisition unit 106 calculates an intermediate correction value Δ q2 for the intermediate angular position by linearly interpolating the correction values Δ q1 for the adjacent 2 angular positions.
As shown in fig. 9, the relative error correction unit 107 also generates error-corrected first absolute angle data abs-1c in which the phase-corrected first absolute angle data abs-1p are corrected by the correction value Δ q1 and the intermediate correction value Δ q2, which are recorded and stored in the memory 102. In this example, the relative error correction unit 107 adds the phase-corrected first absolute angle data abs-1p shown in fig. 9(a) to the correction value Δ q1 and the intermediate correction value Δ q2 shown in fig. 9 (b). Accordingly, the relative error correction unit 107 acquires the error-corrected first absolute angle data abs-1c shown in fig. 9 (c).
Here, the correction value Δ q1 is an error component of the incremental signal converted absolute angle data INC-abs (the N-cycle incremental angle data INC) with respect to the error correction first absolute angle data abs-1p, and the error correction first absolute angle data abs-1c obtained by correcting the phase correction first absolute angle data abs-1p by the correction value Δ q1 and the intermediate correction value Δ q2 has an error component substantially the same as that of the incremental signal converted absolute angle data INC-abs (see fig. 7 (b)). In other words, the error correction first absolute angle data abs-1c has substantially the same error component as the increment angle data INC (see fig. 7 a) for N cycles. Thus, the relative error between the error correction first absolute angle data abs-1c and the incremental angle data INC either disappears or is suppressed. Thus, when the absolute angular position is acquired based on the error correction first absolute angle data abs-1c and the incremental angle data INC, it is possible to suppress a decrease in detection accuracy due to a relative positional shift between the first sensor unit 1a and the second sensor unit 1b or the like.
The correction value acquisition unit 106 may subtract the incremental signal conversion absolute angle data INC-abs from the phase correction first absolute angle data abs-1p to acquire the correction value. In this case, the relative error correction unit 107 subtracts the correction value from the phase corrected first absolute angle data abs-1p to obtain error corrected first absolute angle data abs-1 c.
(Absolute Angle obtaining section)
Next, as shown in fig. 3, the absolute angle acquisition unit 101 includes a second absolute angle data generation unit 110, a first memory 111, a second memory 112, and an angle position determination unit 113. The absolute angle acquisition unit 101 further includes a phase comparison unit 114 and a second phase correction unit 115.
As shown in fig. 10 a, the second absolute angle data generation unit 110 interpolates the error correction first absolute angle data abs-1c obtained in the preprocessing step and divides the data into the number of pairs of magnetic poles (positive integer of N: 2 or more) of the second magnet 30, thereby generating second absolute angle data abs-2. Then, the second absolute angle data generation unit 110 stores and saves the second absolute angle data abs-2 in the first memory 111. Here, the second memory 112 stores and holds incremental angle data INC.
The angular position determining unit 113 determines the instantaneous absolute angular position of the rotating body 2 based on the phase difference Δ p, the first detection result, which is the instantaneous first absolute angle data output from the first sensing unit 1a, the second detection result, which is the instantaneous incremental angle data from the second sensing unit 1b, the second absolute angle data abs-2 stored in the first memory 111, and the incremental angle data INC stored in the second memory 112.
More specifically, when the first detection result (instantaneous first absolute angle data abs-1) from the first sensor unit 1a is acquired, the angular position determination unit 113 calculates a phase-corrected first detection result (instantaneous phase-corrected first absolute angle data abs-1p) obtained by correcting the first detection result by the phase difference Δ p. Then, the angular position determining unit 113 determines the instantaneous absolute angular position of the rotating body 2 by determining, as the upper-level data of the digital data, which cycle of the second absolute angle data abs-2 stored and held in the first memory 111 is the phase-corrected first detection result, and by determining, as the lower-level data of the digital data, which position of the increment angle data INC stored and held in the second memory 112 corresponds to the second detection result (instantaneous increment angle data INC) from the second sensing unit 1 b.
Here, the phase comparison unit 114 compares the phase of the second absolute angle data abs-2 with the phase of the incremental angle data INC at a predetermined timing. When the phase comparison unit 114 determines that the phase of the second absolute angle data abs-2 is out of phase with the incremental angle data INC, the second phase correction unit 115 corrects the second absolute angle data abs-2 so that the phase of the second absolute angle data abs-2 matches the phase of the incremental angle data INC, and stores (rewrites) the corrected second absolute angle data abs-2 in the first memory 111. The predetermined time is, for example, a time point at which the rotary encoder 1 is powered on.
More specifically, as shown in fig. 3, the phase comparison unit 114 includes a third absolute angle data generation unit 116, a first determination unit 117, a second determination unit 118, and a third memory 119.
As shown in fig. 11(b) and 12(b), the third absolute angle data generating unit 116 generates third absolute angle data abs-3 corresponding to the interpolation division of the error correction first absolute angle data abs-1c into (2 × N) pieces, and stores the third absolute angle data abs-3 in the third memory 119.
The first decision unit 117 decides whether or not the second absolute angle data abs-2 has a phase advance with respect to the incremental angle data INC based on the third absolute angle data abs-3. Specifically, as shown in fig. 11 a and 11 b, when the phase correction first detection result is an odd number (for example, i-TH) cycle of the third absolute angle data abs-3 and the second detection result of the second sensor unit 1b is equal to or greater than the first threshold TH1 of the incremental angle data INC, the first determination unit 117 determines that the phase of the second absolute angle data abs-2 is earlier than the phase of the incremental angle data INC. That is, when the phase of the second absolute angle data abs-2 coincides with the phase of the incremental angle data INC, and when the phase correction first detection result is the odd-numbered period of the third absolute angle data abs-3, the second detection result of the second sensor section 1b is smaller than the first threshold TH1 of the incremental angle data INC, it can be detected by the above processing that the phase of the second absolute angle data abs-2 is earlier than the phase of the incremental angle data INC. In this embodiment, the first threshold TH1 is 270 deg.
The second determination section 118 determines whether or not the second absolute angle data abs-2 has a phase delay with respect to the incremental angle data INC based on the third absolute angle data abs-3. Specifically, as shown in fig. 12 a and 12 b, the second determination unit 118 determines that the phase of the second absolute angle data abs-2 is delayed from the phase of the incremental angle data INC when the phase correction first detection result (instantaneous phase correction first absolute angle data abs-1p) obtained by correcting the first detection result of the first sensing unit 1a by the phase difference Δ p is the even-numbered (for example, (i +1) -TH) cycle of the third absolute angle data abs-3 and the second detection result of the second sensing unit 1b is equal to or less than the second threshold TH2 of the incremental angle data INC. That is, when the phase of the second absolute angle data abs-2 coincides with the phase of the incremental angle data INC, and when the phase correction first detection result is the even-numbered cycle of the third absolute angle data abs-3, the second detection result of the second sensor section 1b is larger than the second threshold TH2 of the incremental angle data INC, it is possible to detect that the phase of the second absolute angle data abs-2 is delayed from the phase of the incremental angle data INC by the above-described processing. In this embodiment, the second threshold TH2 is 90 deg.
The second phase correction unit 115 corrects the second absolute angle data abs-2 so that the first detection result of the phase correction is the i-TH (odd-numbered) cycle of the third absolute angle data abs-3 and the second detection result of the second sensing unit 1b becomes the (((i +1)/2) -1) TH cycle (the n-1 TH cycle) of the second absolute angle data abs-2, as shown in fig. 11 c, while the second detection result of the incremental angle data INC is not less than the first threshold TH 1. Thus, the incremental angle data INC coincides with the phase of the corrected second absolute angle data abs-2. Then, the second phase correction unit 115 stores and stores the corrected second absolute angle data abs-2 in the first memory 111.
The second phase correction unit 115 corrects the second absolute angle data abs-2 so that the phase correction first detection result is the (i +1) TH (even) TH cycle of the third absolute angle data abs-3 and the second detection result of the second sensing unit 1b becomes the (((i +1)/2) +1) TH cycle (n +1) TH cycle) of the second absolute angle data abs-2, as shown in fig. 12 c, while the incremental angle data INC is equal to or less than the second threshold TH 2. Thus, the incremental angle data INC coincides with the phase of the corrected second absolute angle data abs-2. Then, the second phase correction section 115 stores and stores the corrected second absolute angle data abs-2 in the first memory 111
The angular position determination unit 113 refers to the second absolute angle data abs-2 stored in the first memory 111 when determining the absolute angular position. Accordingly, the second phase correction unit corrects the second absolute angle data abs-2, stores the corrected second absolute angle data abs-2c in the first memory 111, and then the angular position determination unit 113 determines the absolute angular position based on the corrected second absolute angle data abs-2 c.
(Absolute Angle position acquisition action)
Next, the absolute angular position acquisition operation will be described with reference to fig. 13. The absolute angular position acquisition operation includes a pre-correction step (step ST1) and an absolute angular position acquisition step (step ST 2).
In the pre-correction step (step ST1), the rotating body 2 is rotated, the first absolute angle data abs-1 for 1 cycle of rotation is acquired based on the output of the first sensor unit 1a, and the incremental angle data INC for N cycles of rotation is acquired based on the output of the second sensor unit 1b (step ST 11).
Then, the phase difference acquisition unit 103 acquires the phase difference Δ p between the first absolute angle data abs-1 and the incremental angle data INC (step ST 12: phase difference acquisition step). After the phase difference Δ p is acquired, the converted absolute angle data calculation unit 104 calculates the incremental signal converted absolute angle data INC-abs obtained by converting the incremental angle data INC of N cycles into absolute angle data of one rotation, and the first phase correction unit 105 corrects the first absolute angle data abs-1 based on the phase difference Δ p to generate phase-corrected first absolute angle data abs-1p in which the first absolute angle data abs-1 and the incremental signal converted absolute angle data INC-abs are phase-matched (step ST 13: converted absolute angle data calculation step, first phase correction step).
Then, the correction value acquisition section 106 acquires the correction value Δ q1 based on the difference between the incremental signal conversion absolute angle data INC-abs and the phase correction first absolute angle data abs-1 p. The correction value acquisition unit 106 stores the correction value Δ q1 in a table form in association with the angular position and stores the same in the memory 102. (step ST 14: correction value acquisition step)
When the correction value Δ q1 is acquired, the relative error correction unit 107 corrects the phase-corrected first absolute angle data abs-1p by using the correction value Δ q1 and the intermediate correction value Δ q2 to generate error-corrected first absolute angle data abs-1c (step ST 15: relative error correction step).
Here, the correction value Δ q1 is an error component of the N-cycle incremental angle data INC with respect to the error-corrected first absolute angle data abs-1p, and the error-corrected first absolute angle data abs-1c obtained by correcting the phase-corrected first absolute angle data abs-1p by the correction value Δ q1 and the intermediate correction value Δ q2 has an error component substantially identical to the incremental signal-converted absolute angle data INC-abs (the N-cycle incremental angle data INC). Thus, the relative error between the error correction first absolute angle data abs-1c and the incremental angle data INC either disappears or is suppressed. Thus, in the subsequent absolute angle acquisition step, when the absolute angle position is determined based on the error-corrected first absolute angle data and the incremental angle data, it is possible to suppress a decrease in detection accuracy due to a relative positional shift between the first sensing unit and the second sensing unit. In the pre-correction step, instead of correcting the outputs of the 2 sensor units 1a and 1b with respect to the actual absolute angle, correction is performed to match the outputs of the 2 sensor units 1a and 1 b.
(Absolute Angle obtaining step)
In the absolute angle acquisition step (step ST2), the second absolute angle data generation unit 110 interpolates and divides the error correction first absolute angle data abs-1c into the number of pole pairs (positive integer of N: 2 or more) of the second magnet 30 to generate second absolute angle data abs-2, and stores the second absolute angle data abs-2 in the first memory 111 (step ST 21: second absolute angle data generation step). Thereafter, the rotating body 2 is rotated, and a first detection result of the first sensor unit 1a (instantaneous first absolute angle data output from the first sensor unit 1a) and a second detection result of the second sensor unit 1b (instantaneous incremental angle data output from the second sensor unit 1b) are acquired. The angular position determining unit 113 corrects the first detection result (instantaneous first absolute angle data output from the first sensing unit 1a) by the phase difference Δ p, and calculates a phase-corrected first detection result (instantaneous phase-corrected first absolute angle data).
Here, when the first determination unit 117 and the second determination unit 118 do not determine that the phase of the second absolute angle data abs-2 and the phase of the incremental angle data INC are deviated from each other (when the phase of the second absolute angle data abs-2 and the phase of the incremental angle data INC match each other) (step ST 22: phase comparison step — yes), the angular position determination unit 113 determines which cycle of the second absolute angle data abs-2 stored and held in the first memory 111 as the first data of the digital data as the first detection result of the phase correction, and determines the instantaneous absolute angular position of the rotating body 2 as the second data of the digital data as the position of the incremental angle data INC stored and held in the first memory 111 as the second detection result (step ST 23: angular position determination step).
On the other hand, when the first decision unit 117 determines that the phase of the second absolute angle data abs-2 is earlier than the phase of the incremental angle data INC, or when the superimposition decision unit 118 determines that the phase of the second absolute angle data abs-2 is later than the phase of the incremental angle data INC (step ST 22: phase comparison step-no), the second phase correction unit 115 corrects the second absolute angle data abs-2 so that the phase of the second absolute angle data abs-2 matches the phase of the incremental angle data INC. Then, the corrected second absolute angle data abs-2 is stored in the first time buffer 111 as new second absolute angle data abs-2 (step ST 24: second phase correction step).
Then, the angular position determining unit 113 determines the instantaneous absolute angular position of the rotating body 2 by determining, as the upper level data of the digital data, which cycle of the second absolute angle data abs-2 stored and stored in the first memory 111 is the phase correction first detection result, and by determining, as the lower level data of the digital data, which position of the incremental angle data INC stored and stored in the first memory 111 is the second detection result (step ST 23: angular position determining step).
(modification example)
After the absolute angle acquisition step, a post-correction step of further correcting the absolute angle position detected in the absolute angle acquisition step may be provided. In this case, the error between the absolute angle position detected by the absolute angle acquisition step and the reference absolute angle position acquired by the reference encoder is acquired in advance, stored as position error data in a memory, and the absolute angle position detected by the absolute angle acquisition step is corrected by the position error data so as to match the reference absolute angle position acquired by the reference encoder. The post-correction unit for performing the post-correction step may include: a memory (storage unit); a position error data storage unit that acquires an error between the absolute angle position detected by the absolute angle acquisition step and the reference absolute angle position acquired by the reference encoder, stores the error as position error data, and stores the position error data in a memory (storage unit); and an absolute angle position correction unit that corrects the absolute angle position detected by the absolute angle acquisition unit using the position error data so as to match the reference absolute angle position acquired by the reference encoder.
(other embodiments)
In the magnetoelectric rotary encoder according to the above-described embodiment, the present invention is also applicable to a case where the magnet and the magnetoresistive element are used for the second detection result of the first sensor unit 1a and the second sensor unit 1b, and one or both of the second detection results of the first sensor unit 1a and the second sensor unit 1b is formed of a resolver.
The present invention is also applicable to a resolver of the above-described embodiment using a magneto-electric type or an optical type.
Description of the reference symbols
1 Rotary encoder
1a first sensing part
1b second sensing part
20 first magnet
30 second magnet
40 first magnetoresistive element
51 first Hall element
52 second Hall element
60 second magnetoresistive element
101 absolute angle acquisition unit
102 memory (storage part)
103 phase difference acquisition unit
104 conversion absolute angle data calculating part
105 first phase correcting unit
106 correction value acquisition unit
107 relative error correction unit
110 second absolute angle data generating part
113 angular position determining part
114 phase comparison unit
115 phase correction part
abs-1 first absolute angle data
INC incremental angle data
INC-abs delta signal transformed absolute angle data
L direction of central axis of rotation
Delta p phase difference
Δ q1 correction value
Δ q2 intermediate correction value

Claims (22)

1. A rotary encoder including a first sensor unit that acquires first absolute angle data for 1 cycle of rotation and a second sensor unit that acquires incremental angle data for N cycles of rotation, where N is a positive integer of 2 or more, the rotary encoder detecting an absolute angle position based on a first detection result of the first sensor unit and a second detection result of the second sensor unit, the rotary encoder comprising:
a phase difference acquiring unit that acquires a phase difference between the first absolute angle data and the incremental angle data;
a conversion absolute angle data calculation unit which converts the incremental angle data of N cycles into absolute angle data of one rotation and calculates incremental signal conversion absolute angle data;
a first phase correction unit that corrects the first absolute angle data based on the phase difference and generates phase-corrected first absolute angle data in which a phase of the first absolute angle data matches a phase of the incremental signal conversion absolute angle data;
a correction value obtaining section for obtaining a correction value based on a difference between the incremental signal conversion absolute angle data and the phase correction first absolute angle data;
a relative error correction unit that corrects the phase-corrected first absolute diagonal data by the correction value to generate error-corrected first absolute diagonal data; and
and an absolute angle acquisition unit configured to acquire an absolute angle based on the first detection result, the second detection result, the phase difference, the error correction first absolute angle data, and the incremental angle data.
2. The rotary encoder of claim 1,
the correction value acquisition section acquires the correction value by subtracting the phase correction first absolute angle data from the incremental signal conversion absolute angle data,
the relative error correction unit adds the phase-corrected first absolute angle data to the correction value to obtain the error-corrected first absolute angle data.
3. The rotary encoder of claim 1,
the correction value acquisition section acquires the correction value by subtracting the incremental signal conversion absolute angle data from the phase correction first absolute angle data,
the relative error correction section subtracts the correction value from the phase-corrected first absolute angle data to obtain the error-corrected first absolute angle data.
4. The rotary encoder of claim 2,
and a storage part is also provided, wherein,
the correction value acquisition unit acquires the correction values for a plurality of angular positions in 1 cycle of rotation, stores the correction values in the storage unit in association with the angular positions and the correction values acquired at the angular positions,
the relative error correction section calculates an intermediate correction value of an intermediate angular position between 2 adjacent angular positions based on the correction values acquired at the respective angular positions, and corrects the phase-corrected first absolute angular data using the correction value and the intermediate correction value stored as the correction values and held in the storage section.
5. The rotary encoder of claim 4,
the absolute angle acquisition unit includes:
a second absolute angle data generation unit that generates second absolute angle data obtained by interpolating and dividing the error-corrected first absolute angle data into N pieces;
a phase comparison unit that compares a phase of the second absolute angle data with a phase of the incremental angle data;
a phase correction unit that corrects the second absolute angle data when the phase of the second absolute angle data is different from the phase of the incremental angle data as a result of the comparison by the phase comparison unit; and
and an angle position determination unit configured to determine an absolute angle position of the rotating body based on a phase correction first detection result obtained by correcting the first detection result by the phase difference, the second detection result, the second absolute angle data, and the incremental angle data.
6. The rotary encoder of claim 1,
and a storage part is also provided, wherein,
the correction value acquisition unit acquires the correction values for a plurality of angular positions in 1 cycle of rotation, stores the correction values in the storage unit in association with the angular positions and the correction values acquired at the angular positions,
the relative error correction section calculates an intermediate correction value of an intermediate angular position between 2 adjacent angular positions based on the correction values acquired at the respective angular positions, and corrects the phase-corrected first absolute angular data using the correction value and the intermediate correction value stored as the correction values and held in the storage section.
7. The rotary encoder of claim 1,
the absolute angle acquisition unit includes:
a second absolute angle data generation unit that generates second absolute angle data obtained by interpolating and dividing the error-corrected first absolute angle data into N pieces;
a phase comparison unit that compares a phase of the second absolute angle data with a phase of the incremental angle data;
a phase correction unit that corrects the second absolute angle data when the phase of the second absolute angle data is different from the phase of the incremental angle data as a result of the comparison by the phase comparison unit; and
and an angle position determination unit configured to determine an absolute angle position of the rotating body based on a phase correction first detection result obtained by correcting the first detection result by the phase difference, the second detection result, the second absolute angle data, and the incremental angle data.
8. The rotary encoder of any one of claims 1 to 7,
the first sensor unit includes: a first magnet provided with an N pole and an S pole around a rotation center axis; a first magnetoresistive element opposed to the first magnet in a rotational center axis direction; a first hall element opposed to the first magnet; and a second hall element disposed opposite to the first magnet and at a position shifted from the first hall element by a mechanical angle of 90 ° around the rotation center axis,
the second sensor unit includes: a second magnet having a plurality of pairs of magnetic poles arranged around the rotation center axis; and a second magnetoresistive element opposing the second magnet.
9. The rotary encoder of claim 3,
and a storage part is also provided, wherein,
the correction value acquisition unit acquires the correction values for a plurality of angular positions in 1 cycle of rotation, stores the correction values in the storage unit in association with the angular positions and the correction values acquired at the angular positions,
the relative error correction section calculates an intermediate correction value of an intermediate angular position between 2 adjacent angular positions based on the correction values acquired at the respective angular positions, and corrects the phase-corrected first absolute angular data using the correction value and the intermediate correction value stored as the correction values and held in the storage section.
10. The rotary encoder of claim 9,
the absolute angle acquisition unit includes:
a second absolute angle data generation unit that generates second absolute angle data obtained by interpolating and dividing the error-corrected first absolute angle data into N pieces;
a phase comparison unit that compares a phase of the second absolute angle data with a phase of the incremental angle data;
a phase correction unit that corrects the second absolute angle data when the phase of the second absolute angle data is different from the phase of the incremental angle data as a result of the comparison by the phase comparison unit; and
and an angle position determination unit configured to determine an absolute angle position of the rotating body based on a phase correction first detection result obtained by correcting the first detection result by the phase difference, the second detection result, the second absolute angle data, and the incremental angle data.
11. The rotary encoder of claim 9 or 10,
the first sensor unit includes: a first magnet provided with an N pole and an S pole around a rotation center axis; a first magnetoresistive element opposed to the first magnet in a rotational center axis direction; a first hall element opposed to the first magnet; and a second hall element disposed opposite to the first magnet and at a position shifted from the first hall element by a mechanical angle of 90 ° around the rotation center axis,
the second sensor unit includes: a second magnet having a plurality of pairs of magnetic poles arranged around the rotation center axis; and a second magnetoresistive element opposing the second magnet.
12. An absolute angle position detection method of a rotary encoder including a first sensor unit that acquires first absolute angle data of 1 cycle of rotation and a second sensor unit that acquires incremental angle data of N cycles of rotation, where N is a positive integer of 2 or more, the method detecting an absolute angle position based on a first detection result of the first sensor unit and a second detection result of the second sensor unit, the method comprising:
a phase difference obtaining step of obtaining a phase difference between the first absolute angle data and the incremental angle data;
a conversion absolute angle data calculation step of converting the increment angle data of N cycles into absolute angle data of one rotation to calculate incremental signal conversion absolute angle data;
a first phase correction step of correcting the first absolute angle data based on the phase difference and generating phase-corrected first absolute angle data in which a phase of the first absolute angle data coincides with a phase of the incremental signal conversion absolute angle data;
a correction value obtaining step of obtaining a correction value based on a difference between the incremental signal conversion absolute angle data and the phase correction first absolute angle data;
a relative error correction step of correcting the phase corrected first absolute angle data by the correction value to generate error corrected first absolute angle data; and
an absolute angle acquisition step of acquiring an absolute angle based on the first detection result, the second detection result, the phase difference, the error correction first absolute angle data, and the incremental angle data.
13. The absolute angular position detecting method of a rotary encoder according to claim 12,
the correction value obtaining step of obtaining the correction value by subtracting the phase corrected first absolute angle data from the incremental signal conversion absolute angle data,
in the relative error correction step, the phase corrected first absolute angle data is added to the correction value to obtain the error corrected first absolute angle data.
14. The absolute angular position detecting method of a rotary encoder according to claim 12,
the correction value obtaining step of obtaining the correction value by subtracting the incremental signal conversion absolute angle data from the phase correction first absolute angle data,
in the relative error correction step, the correction value is subtracted from the phase-corrected first absolute angle data to obtain the error-corrected first absolute angle data.
15. The absolute angular position detecting method of a rotary encoder according to claim 13,
the correction value acquisition step acquires the correction values for a plurality of angular positions of 1 cycle of rotation, stores the correction values in a storage unit in association with each angular position and the correction value acquired at the angular position,
in the relative error correction step, an intermediate correction value of an intermediate angular position between 2 adjacent angular positions is calculated based on the correction values acquired at the respective angular positions, and the phase-corrected first absolute angular data is corrected using the correction value and the intermediate correction value stored as the correction values and stored in the storage section.
16. The absolute angular position detecting method of a rotary encoder according to claim 15,
the absolute angle acquiring step includes:
a second absolute angle data generation step of generating second absolute angle data obtained by interpolating and dividing the error correction first absolute angle data into N pieces;
a phase comparison step of comparing the phase of the second absolute angle data with the phase of the incremental angle data;
a second phase correction step of correcting the second absolute angle data when the phase of the second absolute angle data is deviated from the phase of the incremental angle data as a result of the comparison in the phase comparison step; and
an angle position determining step of determining an absolute angle position of the rotating body based on the phase corrected first detection result, the second absolute angle data, and the incremental angle data obtained by correcting the first detection result by the phase difference.
17. The absolute angular position detecting method of a rotary encoder according to claim 12,
the correction value acquisition step acquires the correction values for a plurality of angular positions of 1 cycle of rotation, stores the correction values in a storage unit in association with each angular position and the correction value acquired at the angular position,
in the relative error correction step, an intermediate correction value of an intermediate angular position between 2 adjacent angular positions is calculated based on the correction values acquired at the respective angular positions, and the phase-corrected first absolute angular data is corrected using the correction value and the intermediate correction value stored as the correction values and stored in the storage section.
18. The absolute angular position detecting method of a rotary encoder according to claim 12,
the absolute angle acquiring step includes:
a second absolute angle data generation step of generating second absolute angle data obtained by interpolating and dividing the error correction first absolute angle data into N pieces;
a phase comparison step of comparing the phase of the second absolute angle data with the phase of the incremental angle data;
a second phase correction step of correcting the second absolute angle data when the phase of the second absolute angle data is deviated from the phase of the incremental angle data as a result of the comparison in the phase comparison step; and
an angle position determining step of determining an absolute angle position of the rotating body based on the phase corrected first detection result, the second absolute angle data, and the incremental angle data obtained by correcting the first detection result by the phase difference.
19. The absolute angular position detecting method of a rotary encoder according to any one of claims 12 to 18,
the first sensor unit includes: a first magnet provided with an N pole and an S pole around a rotation center axis; a first magnetoresistive element opposed to the first magnet in a rotational center axis direction; a first hall element opposed to the first magnet; and a second hall element disposed opposite to the first magnet and at a position shifted from the first hall element by a mechanical angle of 90 ° around the rotation center axis,
the second sensor unit includes: a second magnet having a plurality of pairs of magnetic poles arranged around the rotation center axis; and a second magnetoresistive element opposing the second magnet.
20. The absolute angular position detecting method of a rotary encoder according to claim 14,
the correction value acquisition step acquires the correction values for a plurality of angular positions of 1 cycle of rotation, stores the correction values in a storage unit in association with each angular position and the correction value acquired at the angular position,
in the relative error correction step, an intermediate correction value of an intermediate angular position between 2 adjacent angular positions is calculated based on the correction values acquired at the respective angular positions, and the phase-corrected first absolute angular data is corrected using the correction value and the intermediate correction value stored as the correction values and stored in the storage section.
21. The absolute angular position detecting method of a rotary encoder according to claim 20,
the absolute angle acquiring step includes:
a second absolute angle data generation step of generating second absolute angle data obtained by interpolating and dividing the error correction first absolute angle data into N pieces;
a phase comparison step of comparing the phase of the second absolute angle data with the phase of the incremental angle data;
a second phase correction step of correcting the second absolute angle data when the phase of the second absolute angle data is deviated from the phase of the incremental angle data as a result of the comparison in the phase comparison step; and
an angle position determining step of determining an absolute angle position of the rotating body based on the phase corrected first detection result, the second absolute angle data, and the incremental angle data obtained by correcting the first detection result by the phase difference.
22. The absolute angular position detecting method of a rotary encoder according to any one of claims 20 to 21,
the first sensor unit includes: a first magnet provided with an N pole and an S pole around a rotation center axis; a first magnetoresistive element opposed to the first magnet in a rotational center axis direction; a first hall element opposed to the first magnet; and a second hall element disposed opposite to the first magnet and at a position shifted from the first hall element by a mechanical angle of 90 ° around the rotation center axis,
the second sensor unit includes: a second magnet having a plurality of pairs of magnetic poles arranged around the rotation center axis; and a second magnetoresistive element opposing the second magnet.
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Families Citing this family (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP7114315B2 (en) * 2018-04-19 2022-08-08 日本電産サンキョー株式会社 encoder
JP7118809B2 (en) * 2018-08-27 2022-08-16 キヤノン株式会社 Position detection device, device provided with same, position detection method and computer program
CN110567363A (en) * 2019-10-17 2019-12-13 厦门市计量检定测试院 angle detection device and detection method thereof
JP7517927B2 (en) * 2020-09-25 2024-07-17 ニデックインスツルメンツ株式会社 Encoders and Motors
WO2022126596A1 (en) 2020-12-18 2022-06-23 Texas Instruments Incorporated Capacitive-sensing rotary encoder
WO2023240468A1 (en) * 2022-06-14 2023-12-21 华为技术有限公司 Calibration method for angle sensor and sensing system
WO2024134705A1 (en) * 2022-12-19 2024-06-27 デルタ電子株式会社 Magnetic rotary encoder and backup control method therefor

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101115968A (en) * 2005-02-10 2008-01-30 松下电器产业株式会社 Rotation angle detection device and rotation angle correction method
CN101652636A (en) * 2007-04-24 2010-02-17 谐波传动系统有限公司 Magnetic encoder and method of detecting absolute rotational position
JP2013079915A (en) * 2011-10-05 2013-05-02 Mitsutoyo Corp Absolute length measurement type encoder
EP2711663A1 (en) * 2012-09-25 2014-03-26 MCB Industrie High-precision device for magnetic and/or electromagnetic measurement of an angular position of a point
JP5666886B2 (en) * 2010-11-22 2015-02-12 日本電産サンキョー株式会社 Rotary encoder

Family Cites Families (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH09229719A (en) * 1996-02-27 1997-09-05 Mitsubishi Electric Corp Absolute position detector
DE10049502A1 (en) * 2000-10-06 2002-04-11 Heidenhain Gmbh Dr Johannes Method and device for absolute position determination
JP5170046B2 (en) * 2009-09-18 2013-03-27 株式会社安川電機 Rotary encoder, rotary motor, rotary motor system, disk, and method for manufacturing rotary encoder
JP5956207B2 (en) * 2012-03-19 2016-07-27 山洋電気株式会社 Encoder
JP6313571B2 (en) * 2013-11-12 2018-04-18 キヤノン株式会社 POSITION DETECTION DEVICE AND LENS DEVICE AND PHOTOGRAPHING DEVICE HAVING THE SAME
JP2015094682A (en) * 2013-11-13 2015-05-18 キヤノン株式会社 Encoder, device with encoder, position detection method, and position detection processing program

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101115968A (en) * 2005-02-10 2008-01-30 松下电器产业株式会社 Rotation angle detection device and rotation angle correction method
CN101652636A (en) * 2007-04-24 2010-02-17 谐波传动系统有限公司 Magnetic encoder and method of detecting absolute rotational position
JP5666886B2 (en) * 2010-11-22 2015-02-12 日本電産サンキョー株式会社 Rotary encoder
JP2013079915A (en) * 2011-10-05 2013-05-02 Mitsutoyo Corp Absolute length measurement type encoder
EP2711663A1 (en) * 2012-09-25 2014-03-26 MCB Industrie High-precision device for magnetic and/or electromagnetic measurement of an angular position of a point

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