JP6649018B2 - Rotary encoder and method for detecting absolute angular position of rotary encoder - Google Patents

Description

  The present invention relates to a rotary encoder for detecting an absolute angular position of a rotating body at an instant, and a method for detecting an absolute angular position of the rotary encoder.

  A first sensor unit and a second sensor unit are provided as a rotary encoder that detects rotation of the rotating body with respect to the fixed body, and a rotary encoder is provided based on a detection result of the first sensor unit and a detection result of the second sensor unit. Thus, a method of detecting the absolute angular position of the rotating body at the moment has been proposed (see Patent Document 1). For example, the first sensor unit includes a first magnet in which one N pole and one S pole are arranged, a first magnetoresistive element facing the first magnet, and a first Hall element facing the first magnet. And a second Hall element arranged at a position shifted by 90 ° in mechanical angle around the rotation center axis with respect to the first Hall element. Further, the second sensor unit includes a second magnet having a plurality of pole pairs arranged around the rotation center axis and a second magnetoresistive element facing the second magnet. Accordingly, if the angular position of the rotating body at the moment is determined based on the absolute angle data of one cycle per rotation in the first sensor unit and the incremental angle data of N cycles per rotation in the second sensor unit, a high resolution can be obtained. Obtainable.

Japanese Patent No. 5666886

  However, when the first sensor unit and the second sensor unit are used as in the configuration described in Patent Literature 1, relative displacement may occur between the first sensor unit and the second sensor unit. If such a position shift occurs, a phase shift occurs between the absolute angle data in the first sensor unit and the incremental angle data in the second sensor unit, and there is a problem that the detection accuracy is reduced. .

  In view of the above problems, an object of the present invention is to provide a first sensor which detects an absolute angular position of a rotating body based on a detection result of a first sensor unit and a detection result of a second sensor unit. It is an object of the present invention to provide a rotary encoder capable of suppressing a reduction in detection due to a relative displacement between a unit and a second sensor unit, and an absolute angular position detection method for the rotary encoder.

  In order to solve the above problem, the present invention provides a first sensor unit, a second sensor unit, and a first absolute unit of one cycle per rotation in the first sensor unit, where N is a positive integer of 2 or more. A rotary encoder for determining an absolute angle position of a rotating body based on second absolute angle data obtained by interpolating and dividing angle data into N pieces of data and incremental angle data for one rotation N cycles in the second sensor unit. A phase comparison unit that compares the phase of the second absolute angle data with the phase of the incremental angle data, and the phase of the second absolute angle data and the phase of the incremental angle data in the comparison result of the phase comparison unit. And a phase correction unit that corrects the second absolute angle data when there is a deviation.

Further, according to the present invention, when the first sensor unit and the second sensor unit are provided and N is a positive integer of 2 or more, the first absolute angle data of one cycle per rotation in the first sensor unit is N. An absolute angle position detection method of a rotary encoder that determines the absolute angle position of the rotating body based on the second absolute angle data interpolated and divided into pieces and the incremental angle data of N cycles per rotation in the second sensor unit. A phase comparing step of comparing a phase of the second absolute angle data with a phase of the incremental angle data; and a step of comparing the phase of the second absolute angle data with the phase of the incremental angle data. And performing a phase correction step of correcting the second absolute angle data.

  According to the present invention, the absolute angular position of the rotating body at the moment is detected based on the detection result of the first sensor unit and the detection result of the second sensor unit. Therefore, the absolute angular position of the rotating body at the moment can be detected with high resolution. Also, the phase of the absolute angle data (second absolute angle data) in the first sensor unit is compared with the phase of the incremental angle data in the second sensor unit. Correction is performed to match the phase of the absolute angle data (second absolute angle data). For this reason, in the rotary encoder of the type that detects the absolute angular position of the rotating body at the moment based on the detection result of the first sensor unit and the detection result of the second sensor unit, the first sensor unit and the second sensor Even if the phase of the absolute angle data (second absolute angle data) and the phase of the incremental angle data are deviated due to a relative positional deviation between the unit and the like, a decrease in detection accuracy is suppressed. be able to.

  In the rotary encoder according to the present invention, when data obtained by interpolating and dividing the first absolute angle data by (2 × N) times is used as third absolute angle data, the phase comparison unit detects the data by the first sensor unit. When the result is an odd-numbered cycle in the third absolute angle data and the detection result by the second sensor unit is equal to or greater than the first threshold in the incremental angle data, the phase of the second absolute angle data advances. And the detection result by the first sensor unit is an even-numbered cycle in the third absolute angle data, and the detection result by the second sensor unit is equal to or less than a second threshold value in the incremental angle data. It is possible to adopt a mode in which it is determined that the phase of the second absolute angle data is delayed. According to this configuration, it is possible to monitor the phase shift based on the detection result of the first sensor unit and the detection result of the second sensor unit. It is possible to suppress a decrease in detection accuracy due to a relative displacement between the second sensor unit and the like.

  In the method for detecting an absolute angular position of a rotary encoder according to the present invention, when data obtained by interpolating and dividing the first absolute angle data by (2 × N) times is used as third absolute angle data, And when the detection result by the first sensor section is an odd-numbered cycle in the third absolute angle data and the detection result by the second sensor section is equal to or greater than a first threshold value in the incremental angle data, It is determined that the phase of the absolute angle data is advanced, and the detection result by the first sensor unit is an even-numbered cycle in the third absolute angle data, and the detection result by the second sensor unit is the incremental angle data. If the second absolute angle data is equal to or less than the second threshold value, the phase of the second absolute angle data may be determined to be late. According to this configuration, it is possible to monitor the phase shift based on the detection result of the first sensor unit and the detection result of the second sensor unit. It is possible to suppress a decrease in detection accuracy due to a relative displacement between the second sensor unit and the like.

In this case, in the rotary encoder according to the present invention, when i is an odd number, the phase correction unit determines that a current detection result of the first sensor unit is an i-th cycle in the third absolute angle data, The period in which the current detection result by the second sensor unit is equal to or greater than the first threshold value in the incremental angle data is set to be the (((i + 1) / 2) -1) -th cycle in the second absolute angle data. The second absolute angle data is corrected at this time, and the current detection result by the first sensor unit is the (i + 1) -th cycle in the third absolute angle data, and the current detection result by the second sensor unit is For a period of time equal to or less than the second threshold value in the incremental angle data, the (((i + 1) / 2) +1) th cycle in the second absolute angle data is used. The second absolute angle data so that it is possible to adopt a mode of correcting.

  In the present invention, it is preferable that the phase comparison unit compares the phase of the second absolute angle data with the phase of the incremental angle data at each preset timing. According to such a configuration, the relative displacement between the first sensor unit and the second sensor unit in the rotary encoder is monitored at a predetermined timing, so that a decrease in detection accuracy can be suppressed.

  In the present invention, the first sensor section includes a first magnet having one N pole and one S pole arranged around a rotation center axis, and a first magnetoresistive element facing in a rotation center axis direction of the first magnet. An element, a first Hall element facing the first magnet, and a second Hall element arranged at a mechanical angle of 90 ° about the rotation axis with respect to the first Hall element. The second sensor unit may include a second magnet in which a plurality of pairs of poles are arranged around a rotation center axis, and a second magnetoresistive element facing the second magnet. .

  In the present invention, the first magnetoresistance element has a sensor substrate provided on a first surface side, and the first magnetoresistance element is provided on a second surface side of the sensor substrate opposite to the first surface. It is preferable that a first amplifier electrically connected to the first magnetoresistive element via a through hole penetrating the sensor substrate is provided at the overlapping position. According to this configuration, since the signal transmission path between the first magnetoresistive element and the first amplifier is short, the analog signal output from the first magnetoresistive element to the first amplifier is affected by the electromagnetic influence from the first magnet. Hard to receive. Therefore, the analog signal output from the first magnetoresistive element to the first amplifier is unlikely to be distorted.

  In the present invention, the second magnetic resistance element is provided on the first surface side of the sensor substrate, and the sensor substrate is provided at a position overlapping the second magnetic resistance element on the second surface side of the sensor substrate. Preferably, a second amplifier electrically connected to the second magnetoresistive element via a through hole penetrating through the second amplifier is provided. According to this configuration, since the signal transmission path between the second magnetoresistive element and the second amplifier is short, the analog signal output from the second magnetoresistive element to the second amplifier is affected by the electromagnetic influence from the second magnet. Hard to receive. Therefore, the analog signal output from the second magnetoresistive element to the second amplifier is unlikely to be distorted.

  According to the present invention, the absolute angular position of the rotating body at the moment is detected based on the detection result of the first sensor unit and the detection result of the second sensor unit. Therefore, the absolute angular position of the rotating body at the moment can be detected with high resolution. The phase comparing section compares the phase of the absolute angle data (second absolute angle data) in the first sensor section with the phase of the incremental angle data in the second sensor section. In this case, a correction is made to match the phase of the incremental angle data with the phase of the absolute angle data (second absolute angle data). For this reason, in the rotary encoder of the type that detects the absolute angular position of the rotating body at the moment based on the detection result of the first sensor unit and the detection result of the second sensor unit, the first sensor unit and the second sensor Even if the phase of the absolute angle data (second absolute angle data) and the phase of the incremental angle data are deviated due to a relative positional deviation between the unit and the like, a decrease in detection accuracy is suppressed. be able to.

FIG. 2 is an explanatory diagram illustrating an appearance and the like of a rotary encoder to which the present invention is applied. FIG. 3 is a side view showing a fixed body of the rotary encoder to which the present invention is applied, with a part thereof cut away. It is an explanatory view showing composition of a sensor part etc. of a rotary encoder to which the present invention is applied. FIG. 3 is an explanatory diagram of a sensor substrate used in a rotary encoder to which the present invention has been applied. FIG. 3 is an explanatory diagram illustrating a detection principle in a rotary encoder to which the present invention has been applied. FIG. 3 is an explanatory diagram illustrating a basic configuration of a method for determining an angular position in a rotary encoder to which the present invention has been applied. FIG. 4 is an explanatory diagram showing a specific configuration of a method for determining an angular position in a rotary encoder to which the present invention has been applied. FIG. 9 is an explanatory diagram in a case where the phase of the absolute angle data is advanced in the rotary encoder to which the present invention is applied. FIG. 7 is an explanatory diagram in a case where the phase of absolute angle data is delayed in the rotary encoder to which the present invention is applied.

  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, as a rotary encoder, a magnetic rotary encoder in which a sensor unit is configured by a magnet and a magnetic sensing element (a magnetoresistive element, a Hall element) will be mainly described. In this case, any of a configuration in which a magnet is provided in a fixed body and a magnetic sensing element is provided in a rotating body, and a configuration in which a magnetic sensing element is provided in a fixed body and a magnet is provided in a rotating body may be adopted. In the following description, a configuration in which a magnetic sensing element is provided on a fixed body and a magnet is provided on a rotating body will be mainly described. Further, in the drawings referred to below, the configurations of the magnet and the magneto-sensitive element are schematically shown, and the number of the magnetic poles in the second magnet is schematically illustrated with a reduced number. Also, the configuration of the magnetoresistive pattern in the magnetoresistive element (magnetic sensing element) is schematically shown with their positions shifted from each other.

(overall structure)
1A and 1B are explanatory views showing the appearance and the like of a rotary encoder to which the present invention is applied. FIGS. 1A and 1B are perspective views of the rotary encoder viewed from one side and the oblique direction of the rotation axis direction, and It is the top view seen from one side of the direction of a rotation axis. FIG. 2 is a side view in which a part of a fixed body of a rotary encoder to which the present invention is applied is cut away.

  The rotary encoder 1 shown in FIGS. 1 and 2 is a device that magnetically detects the rotation of the rotating body 2 around the axis (around the rotation axis) with respect to the fixed body 10. The fixed body 10 is mounted on a frame of a motor device or the like. The rotating body 2 is used while being fixed and connected to a rotation output shaft or the like of a motor device. The fixed body 10 includes a sensor substrate 15 and a plurality of support members 11 that support the sensor substrate 15. In the present embodiment, the support member 11 includes a bottom plate 121 in which a circular opening 122 is formed. And a sensor support plate 13 fixed to the base body 12. The sensor support plate 13 is fixed by screws 191 and 192 to a substantially cylindrical body 123 protruding from the edge of the opening 122 toward one side L1 in the rotation axis direction L of the base body 12. A plurality of terminals 16 protrude from the sensor support plate 13 toward one side L1 in the rotation axis direction L. A projection 124, a hole 125, and the like are formed on an end surface of the body 123 located on one side L1 in the rotation axis direction L, and the sensor board 15 is screwed to the body 123 using the hole 125 and the like. 193 or the like. At this time, the sensor substrate 15 is accurately fixed in a state where the sensor substrate 15 is positioned at a predetermined position by the protrusion 124 or the like. On the sensor board 15, a connector 17 is provided on a surface on one side L <b> 1 in the rotation axis direction L. The rotating body 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 a method such as fitting. Therefore, the rotating body 2 is rotatable around the axis.

(Layout of magnets and magneto-sensitive elements, etc.)
FIG. 3 is an explanatory diagram showing a configuration of a sensor unit and the like of the rotary encoder 1 to which the present invention is applied. FIGS. 4A and 4B are explanatory diagrams of the sensor substrate 15 used in the rotary encoder 1 to which the present invention is applied. FIGS. 4A and 4B are explanatory diagrams of the first surface 151 of the sensor substrate 15 and a sensor. FIG. 3 is an explanatory diagram of a second surface 152 side of a substrate 15. In FIG. 3, since the data processing unit 90 includes a CPU or the like that operates based on a program stored in advance, the configuration of the data processing unit 90 is shown in a functional block diagram.

  As shown in FIG. 3, the rotary encoder 1 of the present embodiment is provided with two sensor units (a first sensor unit 1a and a second sensor unit 1b) described below. The first sensor unit 1a includes a first magnet 20 on the rotating body 2 side, the first magnet 20 turning a magnetized surface 21 in which an N pole and an S pole are magnetized one by one in the circumferential direction toward one side L1 in the rotation axis direction L. have. The first sensor unit 1a includes a first magnetoresistive element 40 on the fixed body 10 side facing the magnetized surface 21 of the first magnet 20 on one side L1 in the rotation axis direction L, and a first magnet A first Hall element 51 that faces the magnetized surface 21 of the first rotation element 20 on one side L1 in the rotation axis direction L; A second Hall element 52 that faces the magnetized surface 21 of one magnet 20 on one side L1 in the rotation axis direction L.

  The second sensor portion 1b is provided on the rotating body 2 at a position radially outside the first magnet 20 at a position radially outwardly and a plurality of N poles and S poles are alternately magnetized in the circumferential direction. It has the second magnet 30 that directs the magnetic surface 31 to one side L1 in the rotation axis direction L. In the present embodiment, on the magnetized surface 31 of the second magnet 30, a plurality of tracks 310 in which N poles and S poles are alternately magnetized in multiple directions in the circumferential direction are arranged in parallel in the radial direction. In the present embodiment, the tracks 310 are formed in two rows. In this embodiment, when N is a positive integer, a total of N pairs of N poles and S poles are formed in the second magnet 30. In the present embodiment, N is, for example, 128.

  The positions of the N pole and the S pole are shifted in the circumferential direction between the two tracks 310, and in the present embodiment, the N pole and the S pole are shifted by one pole in the circumferential direction between the two tracks 310. In addition, the second sensor section 1b includes, on the side of the fixed body 10, a second magnetoresistive element 60 that faces the magnetized surface 31 of the second magnet 30 on one side L1 in the rotation axis direction L.

  The first magnet 20 and the second magnet 30 rotate around the rotation axis integrally with the rotating body 2. The first magnet 20 is formed of a disk-shaped permanent magnet. The second magnet 30 has a cylindrical shape, and is arranged at a position spaced apart from the first magnet 20 on the radially outer side. The first magnet 20 and the second magnet 30 are made of a bonded magnet or the like.

  The first magnetoresistive element 40 includes a phase A (SIN) magnetoresistive pattern and a phase B (COS) magnetoresistive pattern having a phase difference of 90 ° with respect to the phase of the first magnet 20. 1 is a magnetoresistive element. In the first magnetoresistive element 40, the A-phase magnetoresistive pattern has a + a-phase (SIN +) magnetoresistive pattern 43 and a −a-phase (SIN−) that detect the movement of the rotating body 2 with a phase difference of 180 °. A magnetoresistive pattern 41 is provided. The B-phase magnetoresistive pattern includes a + b-phase (COS +) magnetoresistive pattern 44 and a −b-phase (COS−) magnetoresistive pattern 42 for detecting the movement of the rotating body 2 with a phase difference of 180 °. 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 A bridge circuit is configured similarly to the 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 having a phase difference of 90 ° with respect to the phase of the second magnet 30. . In the second magnetoresistive element 60, the A-phase magnetoresistive pattern has a + a-phase (SIN +) magnetoresistive pattern 64 and a −a-phase (SIN−) that detect the movement of the rotating body 2 with a phase difference of 180 °. A magnetoresistive pattern 62 is provided. The B-phase magnetoresistive pattern includes a + b-phase (COS +) magnetoresistive pattern 63 and a −b-phase (COS−) magnetoresistive pattern 61 for detecting the movement 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 constitute a bridge circuit similarly to the first magnetoresistive element 40, and include the + b-phase magnetoresistive pattern 63 and the -b-phase The magnetoresistive pattern 61 forms a bridge circuit as shown in the same manner as the + a-phase magnetoresistive pattern 64 and the −a-phase magnetoresistive pattern 62.

  In the present embodiment, as shown in FIG. 4A, the first magnetoresistive element 40, the first Hall element 51, the second Hall element 52, and the second magnetoresistive element 60 all rotate the sensor substrate 15. It is provided on the first surface 151 located on the other side L2 in the axial direction L. Further, as shown in FIG. 4B, the sensor substrate 15 is placed on the second surface 152 of the sensor substrate 15 opposite to the first surface 151 at a position overlapping the first magnetoresistive element 40 in a plan view. A first amplifier 91 is provided which is electrically connected to the first magnetoresistive element 40 via a through hole (not shown) penetrating therethrough, and overlaps the second magnetoresistive element 60 on the second surface 152 in plan view. At a position, a second amplifier 92 electrically connected to the second magnetoresistive element 60 via a through hole (not shown) penetrating the sensor substrate 15 is provided. Note that the first Hall element 51 and the second Hall element 52 are electrically connected to the first amplifier 91 via through holes (not shown) penetrating the sensor substrate 15.

  According to such a configuration, since the signal transmission path between the first magnetic resistance element 40 and the first amplifier 91 is short, the analog signal output from the first magnetic resistance element 40 to the first amplifier 91 is Less susceptible to electromagnetic effects. Therefore, the analog signal output from the first magnetoresistive element 40 to the first amplifier 91 is unlikely to be distorted. Further, since the signal transmission path between the second magnetoresistive element 60 and the second amplifier 92 is short, the analog signal output from the second magnetoresistive element 60 to the second amplifier 92 is Less susceptible. Therefore, the analog signal output from the second magnetoresistive element 60 to the second amplifier 92 is unlikely to be distorted.

  Here, each of the first magnetoresistive element 40 and the second magnetoresistive element 60 is mounted on the sensor substrate 15 in a state of a magnetic device in which an element substrate on which a magnetoresistive pattern is formed is housed in a predetermined package. In this embodiment, the lid material used for the package is made of a light-transmitting member such as glass. For this reason, when mounting the magnetic device in which the first and second magnetoresistive elements 40 and 60 are housed in a package on the sensor substrate 15, the first and second magnetoresistive elements 40 and the second The device can be mounted on the sensor substrate 15 while confirming the position of the magnetoresistive element 60 directly.

  It is preferable to use an adhesive having elasticity when the element substrate is housed in the package. According to such a configuration, even when a temperature change or the like occurs, the positions of the first magnetoresistance element 40 and the second magnetoresistance element 60 are not easily shifted.

(Detection principle)
FIGS. 5A and 5B are explanatory diagrams showing the principle of detection in the rotary encoder 1 to which the present invention is applied. FIGS. 5A and 5B are explanatory diagrams of signals output from the magnetoresistive element 4 and the like. FIG. 4 is an explanatory diagram showing a relationship between the rotation position and an angular position (electrical angle) of a rotating body. FIG. 6 is an explanatory diagram showing a basic configuration of a method for determining an angular position in the rotary encoder 1 to which the present invention is applied. FIG. 7 is an explanatory diagram showing a specific configuration of a method for determining an angular position in the rotary encoder 1 to which the present invention has been applied. In FIG. 7, reference numerals 1, 2,... N-1, n, n + 1,... Indicate which positions of the second absolute angle data abs-2 correspond to the true angular position. N, and 1, 2,... M-1, m, m + 1... N indicating which position of the cycle of the incremental angle data INC is a true angular position. .

  As shown in FIG. 3, in the rotary encoder 1 according to the present embodiment, 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 from the first amplifier 91, The data is output via a second amplifier 92 and A / D converters 93a, 93b, and 94 to a data processing unit 90 including a CPU for performing interpolation processing and various arithmetic processing. The data processing unit 90 calculates the absolute angular position of the rotating body 2 with respect to the fixed body 10 based on the outputs from the first magnetoresistive element 40, the first Hall element 51, the second Hall element 52, and the second magnetoresistive element 60. Ask for.

More specifically, in the rotary encoder 1, when the rotating body 2 makes one rotation, the first magnet 20 makes one rotation, so that the first magnetoresistive element 40 of the first sensor unit 1 a receives the signal shown in FIG. The sine wave signals sin and cos shown are output for two periods. Therefore, as shown in FIG. 5B, if the data processing unit 90 obtains θ = tan ⁻¹ (sin / cos) from the sine wave signals sin and cos, the angular position θ of the rotating body 2 can be obtained. In the present embodiment, the first Hall element 51 and the second Hall element 52 are arranged in the first sensor section 1a at positions shifted by 90 ° from the center of the first magnet 20. For this reason, since it is known in which section of the sine wave signal sin or cos the current position is located, the absolute angular position of the rotating body 2 is known.

In the rotary encoder 1 of the present embodiment, the second sensor 30 is provided with the second magnet 30 having the annular magnetized surface 31 in which the N pole and the S pole are alternately magnetized in the circumferential direction. The sine wave signals sin and cos are output from the second magnetoresistive element 60 facing the second magnet 30 every time the rotating body 2 rotates by one period of the magnetic pole of the second magnet 30. . Therefore, for the sine wave signals sin and cos output from the second magnetoresistive element 60, θ = tan ⁻¹ (sin / cos) can be obtained from the sine wave signals sin and cos as shown in FIG. For example, the angular position θ of the rotating body 2 within an angle corresponding to one cycle of the magnetic pole of the second magnet 30 can be obtained.

  Therefore, in the present embodiment, the first absolute angle data abs-1 (see FIG. 6A) for one rotation and one cycle in the first sensor unit 1a and the incremental angle data INC for one rotation N cycle in the second sensor unit 1b. (See FIG. 6B), the angular position of the rotating body 2 at the moment is detected. Therefore, even when the resolution of the first absolute angle data abs-1 is low, it is possible to obtain absolute angle data with high resolution as shown in FIG.

  In adopting such a detection method, as shown in FIG. 7A, the first absolute angle data abs-1 shown in FIG. 6A is converted into the number of magnetic pole pairs of the second magnet 30 (N: 2 or more). The second absolute angle data abs-2 interpolated and divided into (positive integers) is created, and the output from the first sensor unit 1a is instantaneously converted to the second absolute angle data abs-2 shown in FIG. , N + 1, n + 1,... N are detected. The output from the second sensor unit 1b at the moment corresponds to any position in the cycles 1, 2,... M-1, m, m + 1... N of the incremental angle data INC shown in FIG. Or to detect. Then, the output of the first sensor unit 1a at the moment is in the cycle of the second absolute angle data abs-2 shown in FIG. 7A as upper data of the digital data. The absolute angle position of the rotating body 2 at the moment is detected by using which position of the incremental angle data INC shown in FIG.

For this reason, the data processing unit 90 shown in FIG. 3 stores the first memory 96 storing the second absolute angle data abs-2 in the first sensor unit 1a and the incremental angle data INC in the first sensor unit 1a. The second memory 97 to be stored, the output from the first sensor unit 1a at the moment, the output from the second sensor unit 1b at the moment, and the second absolute angle data abs- stored in the first memory 96. 2, and an angular position determining unit 95 for determining the absolute angular position of the rotating body 2 at the moment based on the incremental angle data INC stored in the second memory 97.

(Correction of phase shift)
FIG. 8 is an explanatory diagram when the phase of the absolute angle data is advanced in the rotary encoder 1 to which the present invention is applied. FIG. 9 is an explanatory diagram when the phase of the absolute angle data is delayed in the rotary encoder 1 to which the present invention is applied. FIGS. 8 and 9 show symbols 1, 2,... M-1, m, m + 1,... N indicating which position of each cycle of the incremental angle data INC is a true angular position. And 1, 2,... N-1, n, n + 1,... N indicating which position of the second absolute angle data abs-2 corresponds to the true angular position. Then, reference numerals 1, 2,... I−1, i, i + 1... 2N indicating the positions of the periods are given to the true angular positions of each period of the third absolute angle data abs-3. is there. Here, i is an odd number.

  In the rotary encoder 1 of the present embodiment, the relative displacement between the first sensor unit 1a and the second sensor unit 1b, the error in the characteristics of the members constituting the first sensor unit 1a and the second sensor unit 1b, the first The phase of the second absolute angle data abs-2 may be out of phase with the phase of the incremental angle data INC due to a sampling time difference or the like between the sensor unit 1a and the second sensor unit 1b. I do.

  Therefore, in the rotary encoder 1 of the present embodiment, as shown in FIG. 3, the data processing unit 90 compares the phase of the second absolute angle data abs-2 with the phase of the incremental angle data INC at a preset timing. And the phase of the second absolute angle data abs-2 and the incremental angle when the phase of the second absolute angle data abs-2 and the incremental angle data INC are out of phase in the comparison result of the phase comparator 98. There is provided a phase correction unit 99 for performing correction for matching the phase of the data INC. Therefore, the rotary encoder 1 compares the phase of the second absolute angle data abs-2 with the phase of the incremental angle data INC, and the phase of the second absolute angle data abs-2 and the phase of the incremental angle data INC. A phase correction step of correcting the second absolute angle data abs-2 when the phase is out of phase. Here, the phase comparison unit 98 that compares the phase of the second absolute angle data abs-2 with the phase of the incremental angle data INC directly compares the phase of the second absolute angle data abs-2 with the phase of the incremental angle data INC. Instead, as will be described later, a comparison is performed using the third absolute angle data abs-3 interpolated from the first absolute angle data abs-1 and the incremental angle data INC.

  In the present embodiment, the phase comparison unit 98 outputs the third absolute angle data abs-3 (FIG. 8B, which corresponds to the data obtained by interpolating the first absolute angle data abs-1 into (2 × N) pieces). A third absolute angle data generating unit 985 that generates and stores the third absolute angle data in the third memory 986, and a second absolute angle data INC based on the third absolute angle data abs-3. A first determining unit 981 for determining whether or not the phase of the angle data abs-2 is advanced; and a delay of the phase of the second absolute angle data abs-2 with respect to the incremental angle data INC based on the third absolute angle data abs-3. A second determination unit 982 for determining the presence / absence is provided.

In this embodiment, when performing the phase comparison step and the phase correction step at a preset timing, the rotating body 2 is rotated, and the first sensor unit 1a and the second sensor unit 1 at that moment are rotated.
Obtain the data of b.

  Next, in the phase comparison step, as shown in FIGS. 8A and 8B, the first determination unit 981 determines that the detection result of the first sensor unit 1a is an odd-numbered ( For example, in the (i-th) cycle, when the detection result by the second sensor unit 1b is equal to or greater than the first threshold value TH1 in the incremental angle data INC, the phase of the second absolute angle data abs-2 is the phase of the incremental angle data INC. It is determined that the phase is advanced. That is, when the phase of the second absolute angle data abs-2 coincides with the phase of the incremental angle data INC, the detection result of the first sensor unit 1a is an odd number cycle of the third absolute angle data abs-3. In some cases, the detection result by the second sensor unit 1b is smaller than the first threshold value TH1 in the incremental angle data INC. Therefore, according to the above-described processing, the phase of the second absolute angle data abs-2 is the same as that of the incremental angle data INC. It is possible to detect that the phase is ahead of the phase. In the present embodiment, the first threshold value TH1 is 270 deg in electrical angle.

  Further, in the phase comparison step, as shown in FIGS. 9A and 9B, the second determination unit 982 determines that the detection result by the first sensor unit 1a is an even number (for example, the third absolute angle data abs-3). , (I + 1) -th) cycle, and when the detection result of the second sensor unit 1b is equal to or smaller than the second threshold value TH2 in the incremental angle data INC, the phase of the second absolute angle data abs-2 is changed to the incremental angle data INC. Is determined to be behind the phase. That is, when the phase of the second absolute angle data abs-2 coincides with the phase of the incremental angle data INC, the detection result by the first sensor unit 1a is the even-numbered cycle of the third absolute angle data abs-3. In some cases, the detection result by the second sensor unit 1b exceeds the second threshold value TH2 in the incremental angle data INC. Therefore, according to the above-described processing, the phase of the second absolute angle data abs-2 is changed to the phase of the incremental angle data INC. It is possible to detect that the phase is behind the phase. In the present embodiment, the second threshold value TH2 is 90 deg in electrical angle.

  Next, in the phase correction step, the phase correction unit 99 determines that the detection result by the first sensor unit 1a is the i-th (odd-number) cycle in the third absolute angle data abs-3, and that the second sensor unit 1b In the period in which the detection result is equal to or greater than the first threshold value TH1 in the incremental angle data INC, as shown in FIG. 8C, the (((i + 1) / 2) -1) -th in the second absolute angle data abs-2 The second absolute angle data abs-2 is corrected so as to have a period (n-1st period). Therefore, the phase of the incremental angle data INC matches the phase of the corrected second absolute angle data abs-2. The corrected second absolute angle data abs-2 is stored in the first memory 96.

  On the other hand, in the phase correction step, the phase correction unit 99 determines that the detection result by the first sensor unit 1a is the (i + 1) -th (even-numbered) period in the third absolute angle data abs-3, As shown in FIG. 9C, during the period in which the detection result by the sensor unit 1b is equal to or less than the second threshold value TH2 in the incremental angle data INC, (((i + 1) / 2) in the second absolute angle data abs-2. The second absolute angle data abs-2 is corrected so as to be the (+1) th cycle (the (n + 1) th cycle). Therefore, the phase of the incremental angle data INC matches the phase of the corrected second absolute angle data abs-2. The corrected second absolute angle data abs-2 is stored in the first memory 96.

  Therefore, thereafter, the angular position determining unit 95 determines the corrected second absolute angle data abs-2 stored in the first memory 96 and the incremental angle data INC stored in the second memory 97. The absolute angular position of the rotating body 2 at the moment is detected.

(Main effects of this embodiment)
As described above, in the rotary encoder 1 of the present embodiment, the instantaneous absolute angular position of the rotating body 2 is detected based on the detection result of the first sensor unit 1a and the detection result of the second sensor unit 1b. . Therefore, the angular position of the rotating body 2 at the moment can be detected with high resolution.

  Further, the phase comparing unit 98 compares the phase of the absolute angle data (second absolute angle data abs-2) in the first sensor unit 1a with the phase of the incremental angle data INC in the second sensor unit 1b. When the phase is out of phase, the correction unit 99 corrects the phase of the absolute angle data (second absolute angle data abs-2), and compares the phase of the absolute angle data (second absolute angle data abs-2) with the incremental angle. The phase of the data INC is matched. For this reason, in the rotary encoder 1 that detects the absolute angular position of the rotating body 2 at the moment based on the detection result of the first sensor unit 1a and the detection result of the second sensor unit 1b, the first sensor unit The phase of the absolute angle data (the second absolute angle data abs-2) and the phase of the incremental angle data INC occur due to a relative position shift or the like between the first sensor 1a and the second sensor unit 1b. Even in this case, a decrease in detection accuracy can be suppressed.

  Further, in the phase comparing step, the phase comparing unit 98 performs the second comparison based on the detection result by the first sensor unit 1a, the third absolute angle data abs-3, the detection result by the second sensor unit 1b, and the incremental angle data INC. Since the phase of the absolute angle data abs-2 and the phase of the incremental angle data INC are compared, a decrease in the detection accuracy due to a relative displacement between the first sensor unit 1a and the second sensor unit 1b and the like is prevented. Can be suppressed.

  Further, in the phase correction step, the phase correction unit 99 determines in the comparison result in the phase comparison step (phase comparison unit 98) that the detection result of the first sensor unit 1a indicates the number cycle of the third absolute angle data abs-3. The content to be corrected is determined based on the result of the determination. For this reason, the second absolute angle data abs-2 can be easily corrected.

(Other embodiments)
In the magnetic rotary encoder of the above embodiment, the magnet and the magnetoresistive element are used for the first sensor unit 1a and the second sensor unit 1b, but one or both of the first sensor unit 1a and the second sensor unit 1b are used. The present invention may be applied to a case where a resolver is used.

  Although the rotary encoder according to the above embodiment is a magnetic encoder, the present invention may be applied to an optical rotary encoder.

DESCRIPTION OF SYMBOLS 1 Rotary encoder, 1a 1st sensor part, 1b 2nd sensor part, 2 rotating body, 4 magnetoresistive element, 10 fixed body, 15 sensor board, 20 1st magnet, 21 magnetized surface, 30
2nd magnet, 40 1st magnetoresistive element, 51 1st Hall element, 52 2nd Hall element, 60 2nd magnetoresistive element, 90 data processing part, 91 first amplifier, 92 second amplifier, 95 angular position determination part , 98 phase comparator, 99 phase corrector, 151 first surface, 152
2nd surface, 981 first determination unit, 982 second determination unit, 985 third absolute angle data generation unit, abs-1 first absolute angle data, abs-2 second absolute angle data, abs-3 third absolute angle Data, INC Incremental angle data, L Rotation axis direction

Claims (9)

When N is a positive integer of 2 or more,
A first sensor unit;
A second sensor unit;
Based on the second absolute angle data obtained by interpolating and dividing the first absolute angle data of one cycle per rotation in the first sensor unit into N pieces, and the incremental angle data of N cycles per rotation in the second sensor unit, A rotary encoder for determining an absolute angular position of a rotating body,
A phase comparison unit that compares the phase of the second absolute angle data with the 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 out of phase with the phase of the incremental angle data in the comparison result of the phase comparison unit;
A rotary encoder comprising: When data obtained by interpolating and dividing the first absolute angle data by (2 × N) times is used as third absolute angle data,
In the phase comparison unit, a detection result by the first sensor unit is an odd-numbered cycle in the third absolute angle data, and a detection result by the second sensor unit is equal to or greater than a first threshold value in the incremental angle data. In this case, it is determined that the phase of the second absolute angle data is advanced, and the detection result by the first sensor unit is an even-numbered cycle in the third absolute angle data, and the detection result by the second sensor unit is 2. The rotary encoder according to claim 1, wherein when is less than or equal to a second threshold in the incremental angle data, it is determined that the phase of the second absolute angle data is delayed. 3. When i is odd,
The phase correction unit may be configured such that a detection result by the first sensor unit is an i-th cycle in the third absolute angle data, and a detection result by the second sensor unit is equal to or larger than a first threshold value in the incremental angle data. As for the period, the second absolute angle data is corrected so as to be the (((i + 1) / 2) -1) -th cycle in the second absolute angle data, and the detection result by the first sensor unit is the In the (i + 1) -th cycle in the third absolute angle data, and during a period in which the detection result by the second sensor unit is equal to or less than the second threshold in the incremental angle data, (((i + 1)) in the second absolute angle data 3. The rotary engine according to claim 2, wherein the second absolute angle data is corrected so as to be a cycle of () / 2) +1). Over da. Wherein the phase comparison unit, for each timing set in advance, any one of claims 1 to 3, characterized in that a comparison is made between the second absolute angle data of phase with the incremental angle data phase The rotary encoder according to 1. A first magnet in which one N pole and one S pole are arranged around a rotation center axis; a first magnetoresistive element facing in a rotation center axis direction of the first magnet; A first Hall element facing the first magnet; and a second Hall element disposed at a position shifted by 90 ° in mechanical angle around the rotation center axis with respect to the first Hall element.
The said 2nd sensor part is provided with the 2nd magnet with which the several pole pair was arrange | positioned around the rotation center axis, and the 2nd magnetoresistive element facing the said 2nd magnet, The 1st characterized by the above-mentioned. The rotary encoder according to any one of claims 4 to 4. The first magnetic resistance element has a sensor substrate provided on a first surface side,
At a position overlapping the first magnetoresistive element on a second surface side of the sensor substrate opposite to the first surface, the first magnetoresistive element is electrically connected to the first magnetoresistive element via a through hole penetrating the sensor substrate. The rotary encoder according to claim 5, further comprising a first amplifier connected to the rotary encoder. The second magnetoresistive element is provided on the first surface side of the sensor substrate,
A second amplifier electrically connected to the second magnetoresistive element via a through hole penetrating the sensor board is provided at a position overlapping the second magnetoresistive element on the second surface side of the sensor substrate. The rotary encoder according to claim 6, wherein the rotary encoder is provided. Providing a first sensor unit and a second sensor unit;
When N is a positive integer of 2 or more,
Based on the second absolute angle data obtained by interpolating and dividing the first absolute angle data of one cycle per rotation in the first sensor unit into N pieces, and the incremental angle data of N cycles per rotation in the second sensor unit, An absolute angular position detection method for a rotary encoder that determines an absolute angular position of a rotating body,
A phase comparing step of comparing the phase of the second absolute angle data with the phase of the incremental angle data;
A phase correction step of correcting the second absolute angle data when the phase of the second absolute angle data is out of phase with the phase of the incremental angle data;
A method for detecting the absolute angular position of a rotary encoder. When data obtained by interpolating and dividing the first absolute angle data by (2 × N) times is used as third absolute angle data,
In the phase comparison step, a detection result by the first sensor unit is an odd-numbered cycle in the third absolute angle data, and a detection result by the second sensor unit is equal to or greater than a first threshold value in the incremental angle data. In this case, it is determined that the phase of the second absolute angle data is advanced, and the detection result by the first sensor unit is an even-numbered cycle in the third absolute angle data, and the detection result by the second sensor unit is The absolute angle position detection method for a rotary encoder according to claim 8, wherein when is less than or equal to a second threshold value in the incremental angle data, it is determined that the phase of the second absolute angle data is delayed.

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