JP6386368B2 - Rotary encoder, control method and control program for rotary encoder - Google Patents

Description

  The present invention relates to a rotary encoder, a control method for a rotary encoder, and a control program.

  In the above technical field, Patent Document 1 discloses a technique for correcting components of less than 28th order using a total of ten sensors (4 + 7-1 = 10).

Japanese Patent No. 4984269

  However, the technique described in the above-mentioned document cannot improve the measurement accuracy and reduce the number of sensors.

  The objective of this invention is providing the technique which solves the above-mentioned subject.

In order to achieve the above object, a rotary encoder according to the present invention includes:
A rotary encoder that reads the scale provided on the dial with a sensor,
A reference sensor S ₀ provided at a reference position facing the scale plate,
Q sensors S _i (i is an integer not less than 1 and not more than q) (where q is a positive integer greater than or equal to 1) disposed at positions different from the reference sensor S ₀ ;
Have
The reference sensor S ₀ and the sensor S _i, the outer periphery of Ni equal of the graduation plate (N _i is 3 or more positive integer) provided in a position facing the one of the points, the sensor S _i is of n _i number of equally divided points of the outer periphery of the graduation plate and aliquoted n _i, when the 0-th position of the reference sensor S _0, n-th (n is from 1 to (n _i -1) A positive integer, n and N _i are relatively prime)
Based on the measured value of the sensor S _i and the measured values of the reference sensor S _0, the sensor virtually the N _i equal points other than the position and the reference sensor S ₀ and the sensor S _i is located A correction value calculating means for calculating a virtual measurement value when it is assumed to be arranged, and calculating a correction value for calibration from the virtual measurement value ;
And calibration means for calibrating a measured value by using the correction value when the rotational angle measured by the reference sensor S _0,
It has further.

In order to achieve the above object, a method for controlling a rotary encoder according to the present invention includes:
In order to read the scale provided on the scale board with a sensor,
A reference sensor S ₀ provided at a reference position facing the scale plate,
Q sensors S _i (i is an integer not less than 1 and not more than q) (where q is a positive integer greater than or equal to 1) disposed at positions different from the reference sensor S ₀ ;
Have
The reference sensor S ₀ and the sensor S _i, the outer periphery of the N _i equal the graduation plate (N _i is 3 or more positive integer) provided in a position facing the one of the points, the sensor S _i is of the n _i number of equally divided points of the outer periphery of the graduation plate and aliquoted n _i, when the position of the reference sensor S ₀ and 0 th, n-th (n is from 1 (n _i -1) positive integer, and n and n _i a control method for a rotary encoder has been found formed at a position of relatively prime) of
Based on the measured value of the sensor S _i and the measured values of the reference sensor S _0, the sensor virtually the N _i equal points other than the position and the reference sensor S ₀ and the sensor S _i is located A correction value calculating step for calculating a correction value when it is assumed to be arranged;
A calibration step for calibrating a measured value by using the correction value when the rotational angle measured by the reference sensor S _0,
including.

In order to achieve the above object, a control program for a rotary encoder according to the present invention includes:
In order to read the scale provided on the scale board with a sensor,
A reference sensor S ₀ provided at a reference position facing the scale plate,
Q sensors S _i (i is an integer not less than 1 and not more than q) (where q is a positive integer greater than or equal to 1) disposed at positions different from the reference sensor S ₀ ;
Have
The reference sensor S ₀ and the sensor S _i, the outer periphery of the N _i equal the graduation plate (N _i is 3 or more positive integer) provided in a position facing the one of the points, the sensor S _i is of the n _i number of equally divided points of the outer periphery of the graduation plate and aliquoted n _i, when the position of the reference sensor S ₀ and 0 th, n-th (n is from 1 (n _i -1) positive integer, and n and n _i a control program provided et the rotary encoder to the position of the relatively prime) of
Based on the measured value of the sensor S _i and the measured values of the reference sensor S _0, the sensor virtually the N _i equal points other than the position and the reference sensor S ₀ and the sensor S _i is located A correction value calculating step for calculating a correction value when it is assumed to be arranged;
A calibration step for calibrating a measured value by using the correction value when the rotational angle measured by the reference sensor S _0,
Is executed on the computer.

  According to the present invention, the measurement accuracy can be improved and the number of sensors can be reduced.

It is a block diagram which shows the structure of the rotary encoder which concerns on 1st Embodiment of this invention. It is a figure which shows the outline | summary of operation | movement of the rotary encoder which concerns on 2nd Embodiment of this invention. It is a figure which shows the outline | summary of operation | movement of the rotary encoder which concerns on 2nd Embodiment of this invention. It is a figure which shows the outline | summary of operation | movement of the rotary encoder which concerns on 2nd Embodiment of this invention. It is a figure which shows the outline | summary of operation | movement of the rotary encoder which concerns on 2nd Embodiment of this invention. It is a figure which shows the outline | summary of operation | movement of the rotary encoder which concerns on 2nd Embodiment of this invention. It is a block diagram which shows the structure of the rotary encoder which concerns on 2nd Embodiment of this invention. It is a block diagram which shows the structure of the virtual detection value calculation part of the rotary encoder which concerns on 2nd Embodiment of this invention. It is a flowchart which shows the process sequence of the measurement mode of the rotary encoder which concerns on 2nd Embodiment of this invention. It is a flowchart which shows the process sequence of the calibration mode of the rotary encoder which concerns on 2nd Embodiment of this invention. It is a figure which shows the outline | summary of operation | movement of the rotary encoder which concerns on 3rd Embodiment of this invention. It is a block diagram which shows the structure of the rotary encoder which concerns on 3rd Embodiment of this invention. It is a block diagram which shows the structure of the rotary encoder which concerns on 4th Embodiment of this invention. It is a block diagram which shows the structure of the rotary encoder which concerns on 5th Embodiment of this invention.

  DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments for carrying out the present invention will be exemplarily described in detail with reference to the drawings. However, the configuration, numerical values, process flow, functional elements, and the like described in the following embodiments are merely examples, and modifications and changes are free, and the technical scope of the present invention is described in the following description. It is not intended to be limited.

[First Embodiment]
A rotary encoder 100 according to a first embodiment of the present invention will be described with reference to FIG. The rotary encoder 100 is a device that reads a scale provided on a scale board with a sensor and outputs position information.

As shown in FIG. 1, the rotary encoder 100 includes a reference sensor S ₀ 101, a sensor S _i 102, a virtual detection value calculation unit 103, and a correction unit 104. The reference sensor S ₀ 101 is provided at a reference position facing the scale plate.

The sensors S _i 102 are q sensors (q is a positive integer of 1 or more) arranged at positions different from the reference sensor S ₀ 101. Reference sensor S ₀ 101 and the sensor S _i 102 is the outer circumference of the graduation plate N _i equal parts (N _i is 3 or more positive integer) a position facing either of the points of the reference sensor S ₀ 101 Assuming that the position is 0th, the nth (n is a positive integer from 1 to (N _i −1) among the N _i equality points obtained by equally dividing the outer circumference of the scale plate into N _i , n and N _i Are provided at positions that are relatively prime to each other.

Based on the detection value of the reference sensor S ₀ 101 and the detection value of the sensor S _i 102, the virtual detection value calculation unit 103 is configured such as N _i other than the position where the reference sensor S ₀ 101 and the sensor S _i 102 are arranged. All the virtual detection values when it is assumed that the sensor is arranged at the minute point are calculated.

The correction unit 104 uses at least one of the reference sensor S ₀ 101 and the q sensors S _i 102 using the detection values of the reference sensor S ₀ 101 and the sensor S _i 102 and the calculated value by the virtual detection value calculation unit 103. The detected value is corrected by one.

  According to this embodiment, the measurement accuracy can be improved and the number of sensors can be reduced.

[Second Embodiment]
Next, a rotary encoder according to a second embodiment of the present invention will be described with reference to FIGS. 2A to 2E are diagrams for explaining the outline of the operation of the rotary encoder according to the present embodiment. The rotary encoder 200 is a device that reads a scale provided on a scale board with a sensor and outputs position information.

  As shown in FIG. 2A, the rotary encoder 200 takes the difference between the measured value of the sensor H (0) at the 0 ° position and the measured value of the sensor H (2π / N) at the 2π / N position. The difference is shifted by 2π / N clockwise (2π / N phase shift). This difference data of 2π / N phase shift is equal to the difference between the measured values of the next two sensors when the difference is not phase shifted. That is, it becomes equal to the difference between the measured value of the sensor H (4π / N) at the position of 4π / N and the measured value of the sensor H (2π / N) at the position of 2π / N. Then, by repeating this clockwise phase shift sequentially, finally, only the phase shift of the difference between the measured value of the sensor H (2π / N) and the measured values of H (2π / N) and H (0). All other N halves can be represented.

  Next, as shown in FIG. 2B, the rotary encoder 200 calculates the measured value of the sensor H (0) at the 0 ° position and the measured value of the sensor H (2π / N) at the 2π / N position. The difference is taken, and this difference is shifted by 2π / N counterclockwise (-2π / N phase shift). The difference data shifted by -2π / N phase is equal to the difference between the measured values of the next two sensors when the difference is not phase-shifted. That is, it is equal to the difference between the measured value of the sensor H (2π (N−1) / N) at the position of 2π (N−1) / N and the measured value of the sensor H (0) at the position of 0 °. Become. Then, by repeating this counterclockwise phase shift sequentially, finally, only the phase shift of the difference between the measured value of sensor H (0) and the measured values of H (0) and H (2π / N) is obtained. All other N equivalence points can be represented.

  Based on the measured value of the sensor H (2πk / N) at the position of 2πk / N obtained by the above calculation, the rotary encoder 200 has a statistically superior virtual N or the like by taking an average of these values. You can calculate the measured value of the minute. That is, the rotary encoder 200 can virtually calculate an equal division average when N sensors are arranged in an equal division on the circumference. N is a positive integer of 2 or more, and k is an integer of 0 or more and N−1 or less.

  A correction value of less than the Nth order can be created using the virtually calculated N equal averages. That is, compared with the method described in Patent Document 1, even with a small number of sensors (two for N sensors), the same correction value less than the Nth order can be created.

FIG. 2C and FIG. 2D show an example in which correction values are calculated by arranging four sensors (sensor heads) at 0 °, 120 °, 180 °, and 288 ° positions. In this case, a combination of two sensors, sensor H0 and sensor H180, a combination of sensors H0 and H288, and a combination of sensor H180 and sensor H120, and the combination of sensor H0 and sensor H288 is divided into five equal parts. The combination of sensors H180 and H120 at two locations on (N _i = 5) has a configuration of sensors located at two locations on six equal portions (N _i = 6). Further, one reference sensor (sensor H0) and three other sensors (H120, H180, and H288), that is, the number q of sensors other than the reference sensor is two or more.

The method of selecting a combination of a plurality of N _i with these two N _i = 5 and N _i = 6 is such that the combination of numbers is relatively prime, such as “5” and “6” as shown in this example. However, it is not limited to such a relationship. When the method described in Patent Document 1 is used, two sets of two equal halves every 180 ° (0 ° and 180 °) and three sets of three equal halves every 120 ° (0 °, 120 ° Since the sensor H0 is common (two) in 5 groups (0 °, 72 °, 144 ° 216 ° and 288 °) in 5 equal parts every 72 °, the number of sensors The total is 8 (2 + 3 + 5-2 = 8).

  As shown in FIG. 2C, based on the measurement values of the four sensors, the average of the six measurement values (M6) when six sensors are arranged and the measurement value when five sensors are arranged. The average of 5 (M5) is calculated.

  As shown in FIG. 2D, the graph shown in the lower right shows a combination obtained by performing the same combination as in Patent Document 1 and eliminating components up to the 30th order. The angle error in this case is 0.33 [seconds].

  FIG. 2E shows an example calculated using the technique described in Patent Document 1 when the number of sensors is four. Even with the same number of sensors, the angular error in this case is 0.82 [seconds], which is larger than that of the rotary encoder 200.

  FIG. 3 is a block diagram showing a configuration of the rotary encoder 200 according to the present embodiment. The rotary encoder 200 includes an angle detection unit 301, angle calculators 302 and 304, an angle detection unit 303, an origin signal detection unit 305, an origin detection circuit 306, angle data holding units 307 and 308, and a rotation angle detector 309. The rotary encoder 200 further includes an N-order correction value calculator 310, a correction value temporary holding unit 311, a correction value holding unit 312, a correction value complementing unit 314, a controller 313, an angle data calibration circuit 315, an angle data interface (I / F) 316.

  The angle detection unit 301 detects the angle of the reference position, and the angle detection unit 303 detects the angle of the 2πn / N [rad] position. The angle calculator 302 calculates the angle of the reference position, and the angle calculator 304 calculates the angle of 2πn / N [rad] position. The origin signal detection unit 305 detects the origin signal, and the origin detection circuit 306 detects the origin and sends a reset signal to the angle calculator 304 and further to the angle calculator 302 simultaneously.

  The angle data holding unit 307 holds one round of the reference position angle data calculated by the angle calculator 302, and the angle data holding unit 308 calculates the angle data of 2πn / N [rad] position calculated by the angle calculator 304. Hold. The rotation angle detector 309 detects the rotation angle based on the reference position angle input from the angle calculator 302 and sends the detected rotation angle to the angle data holding unit 308 and the correction value complementing unit 314.

  The Nth order correction value calculator 310 calculates an Nth order correction value based on the virtual detector calculation based on the angle data input from the angle data holding units 307 and 308, and uses the calculated correction value as a correction value temporary holding unit 311. Send to. Here, the Nth order correction value calculator 310 is a calculator that corrects orders other than the Nth order and its harmonics, and the Nth order correction value is a correction value that corrects orders other than the Nth order and its harmonics. is there. The correction value temporary holding unit 311 holds the correction value sent from the Nth order correction value calculator 310. The correction value holding unit 312 stores the correction value sent from the correction value temporary holding unit 311. The correction value holding unit 312 holds the correction value even when the rotary encoder is turned off.

  The controller 313 gives a correction value storage instruction to the correction value temporary storage unit 311, communicates with the external device 317, and receives an angle data capture signal from the rotation angle detector 309. The controller 313 determines whether or not data for one round has been prepared based on the received angle data capture signal. The controller 313 sends the data held in the angle data holding units 307 and 308 to the Nth order correction value calculator 310 and calculates the correction value as shown in the calculation control when the data for one round is prepared. Instructs to perform the operation. Further, the controller 313 instructs the angle data calibration circuit 315 to switch between the calibration mode and the measurement mode. The correction value complementing unit 314 receives and stores the correction value from the correction value holding unit 312 and receives the rotation angle from the rotation angle detector 309. The angle data calibration circuit 315 receives the angle calculated from the angle calculator 302 and receives the correction value from the correction value complementing unit 314.

  The angle data calibration circuit 315 calibrates the angle data based on the received angle and the correction value. The angle data calibration circuit 315 sends the calibrated angle data to the angle data interface 316. The angle data interface 316 transmits the calibrated angle data received from the angle data calibration circuit 315 to the external device 317.

  FIG. 4 is a block diagram showing the configuration of the Nth order correction value calculator 310 of the rotary encoder 200 according to this embodiment. The N-order correction value calculator 310 includes an addition averaging circuit 403, a difference calculation circuit 404, a difference data 2πj / N phase shift circuit 405, a (N−2j) / 2N amplification circuit 406, and an addition circuit 407. The Nth order correction value calculator 310 further includes difference calculation circuits 408 and 409, a −2π / N phase shift circuit 410, an averaging circuit 411, and an Nth order correction value holding unit 412.

  The addition averaging circuit 403 adds the reference position angle data 401 and the 2π / N [rad] position angle data 402 to calculate an average value. The difference calculation circuit 404 calculates the difference between the reference position angle data 401 and the 2π / N [rad] position angle data 402. The difference calculation circuit 404 sends the calculated difference to the difference data 2πj / N phase shift circuit 405. The difference data 2πj / N phase shift circuit 405 shifts the phase of the difference data by 2πj / N and sends it to the (N−2j) / 2N-times amplification circuit 406. The (N−2j) / 2N times amplification circuit 406 amplifies the shifted difference data by (N−2j) / 2N times and sends the amplified difference data to the addition circuit 407. The calculation of the virtual N equal average is performed as follows.

真値：

誤差：

基準ヘッドからθずらして設置したヘッドの読み：

Ｎ個のヘッド（ｋ＝０，１，２・・・Ｎ−１）の平均：Ｈ_N
２．２πｋ／Ｎ（ｋ＝０，１・・・Ｎ，Ｎ−１）の位置に取り付けたヘッドを用いた補正

Ｂ^(N,k)（ｘ）（ｋ＝１，２・・・Ｎ）を均等に取り付けたＮ個のヘッドのうちｋ番目と（ｋ−１）番目のヘッドの差分とすると

（ただしＢ^(N,k)（ｘ）を２πｍ／Ｎだけ位相シフトさせた値をＢ^(N,k,m)（ｘ）と置く）
したがって、

これを用いると、

したがって、

同様の手順で、

これを用いると

より、

したがって、

２通りの方法で求めたＨ_N（ｘ）は理論的には等しい値であるはずなので平均をとって、

これより、Ｈ_N（ｘ）は、２つのヘッドＨ⁰（ｘ）およびＨ^2π/N（ｘ）と、その差分Ｂ^(N,1)（ｘ）の位相シフトであるＢ^(N,1,j)（ｘ）から算出できる。以後は各Ｈ_N（ｘ）を用いて通常のSelfAと同様に組み合わせ法で補正値を作成する。 1. Definition head readings:

true value:

error:

Reading of the head installed with θ deviation from the reference head:

Average of N heads (k = 0, 1, 2,... N−1): H _N
Correction using a head mounted at a position of 2.2πk / N (k = 0, 1... N, N−1)

^Let B ^{(N, k)} (x) (k = 1, 2,... N) be the difference between the k-th head and the (k−1) -th head among the N heads evenly attached.

(However, the value obtained by shifting the phase of B ^{(N, k)} (x) by 2πm / N is set as B ^{(N, k, m)} (x))
Therefore,

With this,

Therefore,

In the same way,

With this

Than,

Therefore,

H _N (x) obtained by two methods should theoretically be equal, so take an average,

Thus, H _N (x) is represented by B ^(N, 1,2) which is the phase shift of the two heads H ⁰ (x) and H ^{2π / N} (x) and the difference B ^{(N, 1)} (x) ^{. j) It} can be calculated from (x). Thereafter, a correction value is created by the combination method in the same manner as normal SelfA using each H _N (x).

  Based on the average value sent from the addition averaging circuit 403 and the amplified difference data sent from the (N−2j) / 2N-times amplification circuit 406, the addition circuit 407 is virtually N equally spaced. An average value of N equal intervals when sensors are arranged is calculated.

  The difference calculation circuit 408 calculates a difference between the virtual N equally spaced average value and the reference position angle data. The difference calculation circuit 409 calculates the difference between the virtual N equally spaced average value and the 2πn / N [rad] position angle data, and sends it to the −2π / N phase shift circuit 410. The −2π / N phase shift circuit 410 shifts the phase of the received difference by −2π / N. The addition averaging circuit 411 adds the difference received from the difference calculation circuit 408 and the phase shifted difference received from the −2π / N phase shift circuit 410 to calculate an average value. The Nth order correction value holding unit 412 holds the Nth order correction value calculated by the addition averaging circuit 411.

  FIG. 5 is a flowchart showing a processing procedure of the measurement mode of the rotary encoder 200 according to the present embodiment. In step S501, the rotary encoder 200 turns on the power based on the operation instruction to turn on the power. In step S503, the rotary encoder 200 activates the communication measurement mode. In step S505, the rotary encoder 200 rotates the stage. In step S507, the rotary encoder 200 determines whether the reference sensor has passed the origin. In step S509, the rotary encoder 200 resets the angle data when the origin signal detection unit 305 passes the origin.

  In step S511, the rotary encoder 200 calculates angle data before the angle data is corrected. In step S513, the rotary encoder 200 reads the correction value. In step S515, the rotary encoder 200 complements the calibration value. In step S517, the rotary encoder 200 calibrates the angle data based on the complemented calibration value. In step S519, the rotary encoder 200 outputs the corrected angle data.

  FIG. 6 is a flowchart showing a processing procedure in the calibration mode of the rotary encoder 200 according to the present embodiment. In step S601, the rotary encoder 200 turns on the power based on the operation instruction to turn on the power. In step S603, the rotary encoder 200 activates the communication calibration mode. In step S605, the rotary encoder 200 rotates the stage. In step S607, the rotary encoder 200 determines whether the reference sensor has passed the origin. In step S609, the rotary encoder 200 resets the angle data when the origin signal detection unit 305 passes the origin.

  In step S611, the rotary encoder 200 calculates angle data. In step S613, the rotary encoder 200 determines whether or not it is the take-in angle. In step S615, the rotary encoder 200 holds the angle data if it is a take-in angle. In step S617, the rotary encoder 200 determines whether or not the holding of the angle data has been completed for all the capture angles. In step S619, the rotary encoder 200 calculates the angle correction value when the holding of the angle data of all the capture angles is completed. In step S621, the rotary encoder 200 determines whether or not to store the angle correction value in the correction value holding unit. If the correction value is stored, the rotary encoder 200 ends the process. If the correction value is not saved, the process returns to step S611 and the subsequent processing is repeated.

  According to this embodiment, the measurement accuracy can be improved and the number of sensors can be reduced. Prior to Patent Document 1, correction of less than 28th order was performed by 28 sensor heads. However, less than 28th order was corrected by (4 + 7-1) = 10 sensor heads using the technique described in Patent Document 1. I was able to do it. That is, even with the technique described in Patent Document 1, correction of less than 28th order could not be made unless 10 sensor heads were attached. On the other hand, in this embodiment, if there are at least three sensor heads, correction of less than 28th order can be performed. Moreover, according to this embodiment, the detection value of sensors other than the reference sensor can be corrected.

[Third Embodiment]
Next, a rotary encoder according to a third embodiment of the present invention will be described with reference to FIGS. FIG. 7 is a diagram for explaining an outline of the operation of the rotary encoder 700 according to the present embodiment. The rotary encoder 700 according to this embodiment is different from the second embodiment in that it has six sensors (6-axis head). Since other configurations and operations are the same as those of the second embodiment, the same configurations and operations are denoted by the same reference numerals, and detailed description thereof is omitted.

  The rotary encoder 700 has a total of six sensors at 0 ° (H0), 72 ° (H72), 120 ° (H120), 180 ° (H180), 252 ° (H252) and 300 ° (H300). doing. The sensor H180 is arranged at a position shifted by 180 ° with respect to the rotation axis with respect to the sensor H0. A sensor H252 is arranged at a position shifted by 180 ° with respect to the rotation axis with respect to the sensor H72. The sensor H300 is arranged at a position shifted from the sensor H120 by 180 ° around the rotation axis. The detection values of the six sensors are used to correct the detection values by the sensor H0.

  A graph 701 shows a simulation result (6 axes) by the rotary encoder 700, and a graph 702 shows a simulation result (8 axes) by the patent document 1. The vertical axis indicates error [second angle], and the horizontal axis indicates brown noise. Brown noise has a characteristic that the low frequency is large and the high frequency is small, and represents the individuality of the sensor (head). Compared with Patent Document 1, the rotary encoder 700 reduces the measurement error after reducing the number of heads by two axes.

  FIG. 8 is a block diagram for explaining the configuration of the rotary encoder 700 according to this embodiment. The rotary encoder includes angle detectors 801, 803, 805, 807, 809, 811 for detecting the angle of each angular position, and angle calculators 802, 804, 806, 808, 810, 812 corresponding to these. .

  The rotary encoder 700 further includes angle data holding units 813 to 818 corresponding to the angle calculators 802, 804, 806, 808, 810, and 812, a 6-detector addition averaging circuit 819, and an addition averaging circuit 820 to 822. Have.

  The rotary encoder 700 further includes a sixth-order correction value calculator 823, a tenth-order correction value calculator 824, a 30th-order correction value calculator 825, an angle shift circuit 826, an angle correction value calculator 827, and a calibration. A value complementing unit 828.

  The angle detection unit 801 detects the angle at the 0 [rad] position. The angle detector 803 detects the angle at the 2π / 2 [rad] position. The angle detection unit 805 detects the angle at the 2π / 3 [rad] position. The angle detection unit 807 detects the angle at the 5π / 3 [rad] position. The angle detection unit 809 detects the angle at the 2π / 5 [rad] position. The angle detection unit 811 detects the angle at the 7π / 5 [rad] position.

  The angle detection units 801, 803, 805, 807, 809, 811 send the detected angles to the corresponding angle calculators 802, 804, 806, 808, 810, 812.

  The angle calculator 802 calculates the angle data of the 0 [rad] position based on the received angle. The angle calculator 804 calculates the angle data at the 2π / 2 [rad] position based on the received angle. The angle calculator 806 calculates the angle data at the 2π / 3 [rad] position based on the received angle.

  The angle calculator 808 calculates the angle data at the 5π / 3 [rad] position based on the received angle. The angle calculator 810 calculates the angle data at the 2π / 5 [rad] position based on the received angle. The angle calculator 812 calculates the angle data at the 7π / 5 [rad] position based on the received angle.

  The angle calculators 802, 804, 806, 808, 810, 812 send the calculated angle data to the angle data holding units 813 to 818.

  The angle data holding unit 813 holds angle data at the 0 [rad] position. The angle data holding unit 814 holds angle data at a position of 2π / 2 [rad]. The angle data holding unit 815 holds angle data at a position of 2π / 3 [rad]. The angle data holding unit 816 holds angle data at a position of 5π / 3 [rad]. The angle data holding unit 817 holds angle data at a position of 2π / 5 [rad]. The angle data holding unit 818 holds angle data at a position of 7π / 5 [rad].

  The angle data holding units 813 and 814 send the held angle data to the addition averaging circuit 820. The angle data holding units 815 and 816 send the held angle data to the addition averaging circuit 821. The angle data holding units 817 and 818 send the held angle data to the addition averaging circuit 822.

  The addition averaging circuit 820 to 822 adds the received angle data and calculates an average value. The addition averaging circuit 820 sends the calculated average value to the sixth-order correction value calculator 823 and the tenth-order correction value calculator 824. The addition average circuit 821 sends the calculated average value to the sixth-order correction value calculator 823, and the addition average circuit 822 sends the calculated average value to the tenth-order correction value calculator 824.

  The sixth-order correction value calculator 823 calculates a sixth-order correction value based on the virtual detector calculation based on the received average value, and sends it to the 30th-order correction value calculator 825. The tenth-order correction value calculator 824 calculates a tenth-order correction value based on the virtual detector calculation based on the received average value, and sends it to the thirty-order correction value calculator. The 30th-order correction value calculator 825 calculates a 30th-order correction value by the combination method based on the received 6th-order correction value and 10th-order correction value, and sends the calculation result to the angle shift circuit 826.

  The angle shift circuit 826 shifts the angle based on the received 30th-order correction value, and sends the shift result to the angle correction value calculator 827. The angle correction value calculator 827 calculates an angle correction value based on the received angle shift result.

  The 6-detector addition averaging circuit 819 adds the angle data calculated by the angle calculators 802, 804, 806, 808, 810, and 812 to calculate an average value. The calibration value complementing unit 828 supplements the calibration value based on the data received from the rotation angle detector 309 and the 6-detector addition averaging circuit.

  According to the present embodiment, the measurement accuracy is improved and the number of sensors can be reduced from 8 to 6 as compared with Patent Document 1. In addition, since two sensors that are always symmetrical with respect to the rotational axis can be arranged as a set of sensors, the sensor is not affected by shaft blurring due to eccentricity. Furthermore, since all the sensors are arranged symmetrically, all the sensors can be used for measurement, and the influence of the individuality of the sensors can be averaged to make it smaller.

[Fourth Embodiment]
Next, a rotary encoder according to a fourth embodiment of the invention will be described with reference to FIG. FIG. 9 is a block diagram for explaining the configuration of the rotary encoder 900 according to the present embodiment. In addition, the same code | symbol is attached | subjected about the same structure and operation | movement as said 2nd Embodiment, and the detailed description is abbreviate | omitted. The rotary encoder 900 according to the present embodiment calculates a sixth-order correction value based on three sensors.

  The rotary encoder 900 includes an angle detector 901 at 2π / 2 [rad] position, an angle detector 903 at 2π / 3 [rad] position, an angle calculator 902 at 2π / 2 [rad] position, and 2π / 3. [Rad] position angle calculator 904. The rotary encoder 900 further includes an angle data holding unit 905 at a 2π / 2 [rad] position, an angle data holding unit 906 at a 2π / 3 [rad] position, a secondary correction value calculator 909, and a secondary correction value. An arithmetic unit 910 and a sixth-order correction value arithmetic unit 912 are included. The rotary encoder 900 further includes a two-detector averaging circuit 908, an angle shift circuit 913, and an angle correction value calculator 914.

  The angle detector 901 detects the angle at the 2π / 2 [rad] position, and sends the detected angle to the angle calculator 902 at the 2π / 2 [rad] position. Similarly, the angle detector 903 detects the angle at the 2π / 3 [rad] position, and sends the detected angle to the angle calculator 904 at the 2π / 3 [rad] position.

  The angle calculator 902 calculates the angle data at the 2π / 2 [rad] position based on the received angle, and sends the angle data at the 2π / 2 [rad] position to the angle data holding unit 905. The angle calculator 904 calculates the angle data at the 2π / 3 [rad] position based on the received angle, and sends the angle data at the 2π / 3 [rad] position to the angle data holding unit 906.

  The secondary correction value calculator 909 calculates a secondary correction value based on the angle data received from the angle data holding units 307 and 905. The tertiary correction value calculator 910 calculates a tertiary correction value by virtual detector calculation based on the angle data received from the angle data holding units 307 and 906. The sixth-order correction value calculator 912 is based on the second-order correction value and the third-order correction value received from the second-order correction value calculator 909 and the third-order correction value calculator 910, and the sixth-order correction value based on the combination method. Is calculated.

  The angle shift circuit 913 shifts the angle based on the sixth-order correction value received from the sixth-order correction value calculator 912, and sends the shifted angle to the angle correction value calculator 914. The angle correction value calculator 914 calculates an angle correction value based on the received shift angle.

  According to this embodiment, it is possible to correct up to the sixth order with three sensors, so that the measurement accuracy can be improved and the number of sensors can be reduced.

[Fifth Embodiment]
Next, a rotary encoder according to a fifth embodiment of the invention will be described with reference to FIG. FIG. 10 is a block diagram for explaining the configuration of the rotary encoder 1000 according to the present embodiment. In addition, the same code | symbol is attached | subjected about the same structure and operation | movement as said 2nd Embodiment, and the detailed description is abbreviate | omitted. The rotary encoder 1000 according to the present embodiment performs N × M-order correction based on three sensors.

  The rotary encoder 1000 includes an angle detector 1001 at a 2πm / M [rad] position, an angle calculator 1002 at a 2πm / M position, an angle data holding unit 1003 at a 2πm / M [rad] position, and an M-order correction value calculation. And an N × M-order correction value calculator.

  The angle detector 1001 detects the angle at the 2πm / M [rad] position, and sends the detected angle to the angle calculator 1002 at the 2πm / M [rad] position. The angle calculator 1002 calculates angle data based on the received angle at the 2πm / M [rad] position, and sends the angle data to the angle data holding unit 1003.

  The Mth order correction value calculator 1004 receives the angle data of the reference position and the angle data of the 2πm / M [rad] position from the angle data holding units 307 and 1003, respectively. The M-order correction value calculator 1004 calculates an M-order correction value by virtual detector calculation based on the received angle data, and sends it to the N × M-order correction value calculator 1005. The N × M-th order correction value calculator 1005 performs N × M correction by a combination method based on the N-th order correction value and the M-th order correction value received from the N-order correction value calculator 310 and the M-order correction value calculator 1004. The Mth order correction value is calculated.

  According to the present embodiment, the correction up to the N × M order can be performed with three sensors, so that the measurement accuracy can be improved and the number of sensors can be reduced.

[Other Embodiments]
While the present invention has been described with reference to the embodiments, the present invention is not limited to the above embodiments. Various changes that can be understood by those skilled in the art can be made to the configuration and details of the present invention within the scope of the present invention. In addition, a system or an apparatus in which different features included in each embodiment are combined in any way is also included in the scope of the present invention.

  In addition, the present invention may be applied to a system composed of a plurality of devices, or may be applied to a single device. Furthermore, the present invention can also be applied to a case where an information processing program that implements the functions of the embodiments is supplied directly or remotely to a system or apparatus. Therefore, in order to realize the functions of the present invention on a computer, a program installed in the computer, a medium storing the program, and a WWW (World Wide Web) server that downloads the program are also included in the scope of the present invention. . In particular, at least a non-transitory computer readable medium storing a program for causing a computer to execute the processing steps included in the above-described embodiments is included in the scope of the present invention.

Claims (7)

A rotary encoder that reads the scale provided on the dial with a sensor,
A reference sensor S ₀ provided at a reference position facing the scale plate,
Q sensors S _i (i is an integer not less than 1 and not more than q) (where q is a positive integer greater than or equal to 1) disposed at positions different from the reference sensor S ₀ ;
Have
The reference sensor S ₀ and the sensor S _i, the outer periphery of Ni equal of the graduation plate (N _i is 3 or more positive integer) provided in a position facing the one of the points, the sensor S _i is of n _i number of equally divided points of the outer periphery of the graduation plate and aliquoted n _i, when the 0-th position of the reference sensor S _0, n-th (n is from 1 to (n _i -1) A positive integer, n and N _i are relatively prime)
Based on the measured value of the sensor S _i and the measured values of the reference sensor S _0, the sensor virtually the N _i equal points other than the position and the reference sensor S ₀ and the sensor S _i is located A correction value calculating means for calculating a virtual measurement value when it is assumed to be arranged, and calculating a correction value for calibration from the virtual measurement value ;
And calibration means for calibrating a measured value by using the correction value when the rotational angle measured by the reference sensor S _0,
The rotary encoder further comprising: Q is a positive integer of 2 or more;
The rotary encoder according to claim 1, wherein the N _i are prime to each other. A sensor provided at a position shifted by 180 ° about the rotation axis with respect to at least one of the reference sensor S ₀ and the q sensors S _i ;
Said correction value calculating means, relative to the sensor S _i, further using measurements of sensors provided in positions shifted 180 ° around a rotation axis, and performs the calculation of the correction value The rotary encoder according to claim 1 or 2. The rotary encoder according to claim 1, wherein q = 1 and N ₁ = 3. The rotary encoder according to claim ₁ , wherein q = 2, N ₁ = 3, and N ₂ = 5. In order to read the scale provided on the scale board with a sensor,
A reference sensor S ₀ provided at a reference position facing the scale plate,
Q sensors S _i (i is an integer not less than 1 and not more than q) (where q is a positive integer greater than or equal to 1) disposed at positions different from the reference sensor S ₀ ;
Have
The reference sensor S ₀ and the sensor S _i, the outer periphery of the N _i equal the graduation plate (N _i is 3 or more positive integer) provided in a position facing the one of the points, the sensor S _i is of the n _i number of equally divided points of the outer periphery of the graduation plate and aliquoted n _i, when the position of the reference sensor S ₀ and 0 th, n-th (n is from 1 (n _i -1) positive integer, and n and n _i a control method for a rotary encoder has been found formed at a position of relatively prime) of
Based on the measured value of the sensor S _i and the measured values of the reference sensor S _0, the sensor virtually the N _i equal points other than the position and the reference sensor S ₀ and the sensor S _i is located A correction value calculating step for calculating a correction value when it is assumed to be arranged;
A calibration step for calibrating a measured value by using the correction value when the rotational angle measured by the reference sensor S _0,
The control method characterized by including. A reference sensor S ₀ provided at a reference position facing the scale plate ,
Q sensors S _i (i is an integer not less than 1 and not more than q) (where q is a positive integer greater than or equal to 1) disposed at positions different from the reference sensor S ₀ ;
Have
The reference sensor S ₀ and the sensor S _i, the outer periphery of the N _i equal the graduation plate (N _i is 3 or more positive integer) provided in a position facing the one of the points, the sensor S _i is of the n _i number of equally divided points of the outer periphery of the graduation plate and aliquoted n _i, when the position of the reference sensor S ₀ and 0 th, n-th (n is from 1 (n _i -1) positive integer, and n and n _i a control program provided et the rotary encoder to the position of the relatively prime) of
Based on the measured value of the sensor S _i and the measured values of the reference sensor S _0, the sensor virtually the N _i equal points other than the position and the reference sensor S ₀ and the sensor S _i is located A correction value calculating step for calculating a correction value when it is assumed to be arranged;
A calibration step for calibrating a measured value by using the correction value when the rotational angle measured by the reference sensor S _0,
A control program for causing a computer to execute.

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