JP2013228313A - Encoder and drive device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To detect positional information with high accuracy.SOLUTION: An encoder includes: the n-number of detection elements which output cycle signals in accordance with positional information on a body to be driven and are arranged so that the n-number of output signals having different phases from each other obtained by dividing an 'a' cycle (where |a|=(m-k×n), k is an integer of 1 or more) are obtained in a displaced range of the body to be driven in which an 'm' cycle (where m is an integer of 2 or more) of a cycle signal is obtained; a signal generation unit which generates processing signals having the 'a' cycle on the basis of the n number of output signals outputted by the n number of detection elements; and a detection unit which detects the positional information on the body to be driven on the basis of the processing signals having the 'a' cycle generated by the signal generation unit.

Description

  The present invention relates to an encoder and a drive device.

  In recent years, an encoder is known as a device for detecting position information such as a rotation angle. Such an encoder uses a two-phase signal of a sine wave and a cosine wave obtained from an optical or magnetic detector (see, for example, Patent Document 1). For example, such an encoder performs an arc tangent calculation (arctan interpolation) after processing signals shifted from each other by 90 ° obtained from two detection elements, and calculates a phase difference between the generated detection signal and a reference signal. By detecting, position information such as a rotation angle is detected.

JP 2000-314638 A

However, in the encoder as described above, for example, when a high-order component distortion occurs in the detection signal obtained from the detection element, the generated distortion may be detected as an error in position information.
Thus, the encoder as described above has a problem that it is difficult to detect position information with high accuracy.

  The present invention has been made to solve the above problems, and an object of the present invention is to provide an encoder and a driving apparatus that can detect position information with high accuracy.

  In order to solve the above-described problem, an embodiment of the present invention includes n detection elements that output a periodic signal according to position information of a driven body, and m periods (where m is 2) of the periodic signal. N outputs having different phases obtained by dividing a period (where | a | = (m−k × n), k is an integer equal to or greater than 1) in the displacement range of the driven body from which the above is obtained. N detection elements arranged to obtain a signal, a signal generation unit that generates the processing signal of the period a based on the n output signals output from the n detection elements, An encoder comprising: a detection unit configured to detect position information of the driven body based on the processing signal of the period a generated by the signal generation unit.

  In addition, an embodiment of the present invention is a drive device including the encoder described above and a drive unit that drives the driven body.

  According to the present invention, position information can be detected with high accuracy.

It is a schematic block diagram which shows an example of a structure of the encoder by 1st Embodiment. It is a block diagram which shows the structure of the encoder in 1st Embodiment. It is a figure which shows the output waveform of the magnetic sensor part in 1st Embodiment. It is a figure explaining the reduction | restoration of the distortion component in 1st Embodiment. It is a block diagram which shows the structure of the encoder in 2nd Embodiment. It is a block diagram which shows the structure of the encoder in 3rd Embodiment. It is a block diagram which shows the structure of the encoder in 4th Embodiment. It is a schematic block diagram which shows an example of a structure of the encoder by 5th Embodiment. It is a block diagram which shows the structure of the encoder in 5th Embodiment. It is the schematic of the drive device in this embodiment. It is the schematic of a drive device provided with the reduction gear in this embodiment. It is a schematic block diagram which shows the structure of the encoder by a 1st modification. It is a figure which shows the output waveform of the magnetic sensor part in a 1st modification. It is a schematic block diagram which shows the structure of the encoder by a 2nd modification. It is a figure which shows the output waveform of the magnetic sensor part in a 2nd modification. It is a schematic block diagram which shows the structure of the encoder by a 3rd modification. It is a block diagram which shows the structure of the encoder in a 3rd modification. It is a figure which shows the output waveform of the optical sensor part in a 3rd modification. It is a schematic block diagram which shows the structure of the encoder by a 4th modification. It is a schematic block diagram which shows the structure of the encoder by the 5th modification. It is a figure which shows the output waveform of the optical sensor part in a 5th modification. It is a schematic block diagram which shows the structure of the encoder by the 6th modification. It is a schematic block diagram which shows another structural example of the encoder by a 6th modification. It is a schematic block diagram which shows the structure of the encoder by the 7th modification. It is a schematic block diagram which shows the structure of the encoder by the 8th modification. It is a figure which shows the output waveform of the optical sensor part in the 8th modification. It is a figure which shows the structure of the encoder in a 9th modification, and the output waveform of an optical sensor part. It is a schematic block diagram which shows the structure of the encoder by the 10th modification.

Hereinafter, a position detection device (encoder) according to an embodiment of the present invention will be described with reference to the drawings.
[First Embodiment]
In this embodiment, a magnetic rotary encoder will be described as an example.
FIG. 1 is a schematic configuration diagram showing an example of the configuration of the encoder 1 according to the first embodiment.
In FIG. 1, an encoder 1 includes a rotor 6 having a magnet 5 (9-pole multipole magnet) and a disk 61, and a plurality (for example, 8) magnetic detection elements 11 to 18 and a substrate 7 on which the magnetic detection elements 11 to 18 and other control components are mounted. Here, the position in the vicinity of the magnet 5 is, for example, around the magnet 5 and includes a position sufficient for the magnetic detection elements 11 to 18 to detect a change in the magnetic field strength caused by the magnet 5.

  Here, FIG. 1A shows a front view of the encoder 1 viewed from the rotation axis direction (Z-axis direction) of the rotor 6, and FIG. 1B shows a cross section of the encoder 1 along the line AA ′. The figure is shown.

  The magnet 5 is, for example, a permanent magnet and a multipolar magnet. In the present embodiment, as an example, the magnet 5 is a permanent magnet having a number of magnetic poles of “9”. Here, the “number of magnetic poles” indicates the number of pairs of S (S) poles 5S and N (N) poles 5N. That is, the magnet 5 is a permanent magnet having nine pairs of S poles 5S and N poles 5N (9 poles in one circumference of the rotor 6). The magnet 5 is disposed on the circumference of the rotor 6 in contact with the donut-shaped groove of the disk 61.

  The magnetic detection elements 11 to 18 (detection elements) are, for example, Hall elements (HS), respectively. Hereinafter, the magnetic detection elements 11, 12, 13, 14, 15, 16, 17, 18 are referred to as Hall elements 11, 12, 13, 14, 15, 16, 17, 18 and will be described below. Further, in the case where any Hall element among Hall elements 11, 12, 13, 14, 15, 15, 16, 17, and 18 or a Hall element included in the encoder 1 is simply indicated, the Hall element 10 (detection element). Will be described below. Moreover, in this embodiment, the structure part which shows the whole Hall element 11, 12, 13, 14, 15, 15, 16, 17, 18 corresponds to the magnetic sensor part 20 (sensor part).

  The Hall elements 11 to 18 are arranged so as to face the magnet 5 on the circumference that is equidistant from the rotation axis of the rotor 6 in the above-described donut-shaped groove. The eight Hall elements 11 to 18 each output a periodic signal according to position information of the rotor 6 (driven body). In addition, the eight Hall elements 11 to 18 obtain eight output signals having different phases obtained by equally dividing the period a in the displacement range of the rotor 6 where the period m of the periodic signal is obtained. Are arranged to be. However, | a | = (m−k × n), k is an integer of 1 or more, and m is an integer of 2 or more. Further, n is the number of Hall elements 10, and here, n = 8. Further, the period a is an integer, and when the value of a is negative, it indicates that the phase of the processing signal appearing in aliasing in the discrete Fourier transform described later is rotated by 180 °.

Here, the displacement range of the rotor 6 in which m cycles (eg, 9 cycles) are obtained is the range of one rotation of the rotor 6, and the eight output signals are a cycle (eg, | a | = (9-1 × 8) = 1 period) are arranged so that eight output signals having a phase divided equally can be obtained. The m period and the number n of the Hall elements 10 are set such that an a-period processed signal can be detected from an m-period signal using aliasing (folding distortion) in discrete Fourier transform. In this embodiment, since the period a is one period, the processing signal for detecting position information is a processing signal (fundamental wave (primary) signal) of one period. Note that the “equivalent” described above includes “substantially equal”.
Further, the eight Hall elements 11 to 18 have, for example, the same detection sensitivity and each have the same output level.

  Here, “aliasing” means that, for example, when a signal waveform is sampled at a predetermined sampling frequency (fs), a signal having a frequency different from that of the signal appears when the frequency of the signal becomes higher than (fs / 2). It is a phenomenon. In this embodiment, the signal waveform corresponds to a periodic signal with m periods, and the number of periods (number of cycles) m corresponds to the spatial frequency of the periodic signal. The sampling frequency (fs) corresponds to n, which is the number of Hall elements 10. From this, the m period is a value larger than a half of the number n of the Hall elements 10. For example, when the number of Hall elements 10 is 8, the m period needs to be 4 or more. In addition, in order to detect an a-cycle processing signal having a lower order than the m cycle, which is easy to process, from an m-cycle signal using “aliasing”, the a cycle, m cycle, and n values are: As described above, it is set so as to satisfy | a | = (m−k × n). In the present embodiment, by using this “aliasing”, for example, a period signal of 9 periods (m = 9) is converted into one period (a = 1) by detection signals of eight (n = 8) Hall elements 10. ) Processing signal can be detected.

  In the present embodiment, the m period is an example in the case where the m period is equal to the cycle number (here, 9 cycles) of the periodic signal in the entire displacement range of the rotor 6 (one rotation or one rotation of the rotor 6). is there. Here, the cycle number indicates the number of one cycle of the periodic signal that is the output signal of the Hall element 10, and the cycle number of the periodic signal in the entire displacement range of the rotor 6 corresponds to the number of magnetic poles of the magnet 5.

  In addition, the eight Hall elements 11 to 18 are equally arranged in the displacement range (for example, one rotation) of the rotor 6 in which m periods (for example, nine periods) are obtained. In addition, the eight Hall elements 11 to 18 are arranged so that eight output signals having the same phase difference can be obtained in the displacement range (for example, one rotation) of the rotor 6 in which m periods can be obtained. Yes.

In FIG. 1, when the rotor 6 (driven body) rotates about the rotation axis in the Z-axis direction, the magnet 5 rotates with the rotation of the rotor 6, and the magnet 5 detected by the Hall elements 11 to 18. The magnetic field from The encoder 1 detects the change of the magnetic field by each of the eight hall elements 11 to 18, and detects the position information of the rotor 6 from the detected change amount of the magnetic field.
Here, the “position information” in the present embodiment includes information indicating a rotation angle, a rotation position, a rotation angle, a rotation speed, and the like.

FIG. 2 is a block diagram showing a configuration of the encoder 1 in the present embodiment.
In FIG. 2, the encoder 1 includes a magnetic sensor unit 20, a switch unit 2, an A / D (analog / digital) conversion unit 3, and a signal processing unit 4. Here, the magnetic sensor unit 20 has eight Hall elements 11 to 18.

Each Hall element 10 outputs a sinusoidal output signal of one cycle when the rotor 6 moves within the range of one pole of the magnet 5 (one pitch of the magnet 5). As described above, each Hall element 10 outputs a sinusoidal output signal of 9 periods (the number of cycles 9) when the rotor 6 rotates once.
Hereinafter, the output signal of the Hall element 10 will be described simply as “output signal”.

  The switch unit 2 (switching unit) is, for example, an analog switch that includes at least eight first terminals and one second terminal. The output signal lines of the eight hall elements 10 are connected to the first terminal of the switch unit 2. The switch unit 2 selects one of the eight first terminals based on a control signal output from the switching control unit 41 of the signal processing unit 4 to be described later, and this selected first Are connected to the second terminal. That is, the switch unit 2 outputs an output signal of any one of the Hall elements 11 to 18 to the A / D conversion unit 3 based on the control signal output from the switching control unit 41. For example, the switch unit 2 sequentially switches and outputs eight output signals in a predetermined order.

  The A / D converter 3 is, for example, an analog / digital conversion circuit (A / D converter) that converts an analog signal into a digital signal at a predetermined sampling period. The A / D converter 3 outputs an output signal obtained by converting an analog signal, which is an output signal of the Hall element 10 output from the switch unit 2, into a digital signal, to the signal processor 4.

  The signal processing unit 4 executes signal processing of the encoder 1. The signal processing unit 4 includes a switching control unit 41 and a position detection unit 42.

The switching control unit 41 generates a control signal that is a switching signal (selection signal) of the switch unit 2. That is, the switching control unit 41 outputs a control signal and sequentially outputs the output signals of the Hall elements 11 to 18 to the switch unit 2 by switching the output signals of the Hall elements 11 to 18 in, for example, clockwise order ( (Sequential output).
Note that the sequential output refers to, for example, sequentially (sequentially) outputting the output signals of the Hall elements 11 to 18. In the present embodiment, as an example, the switching control unit 41 switches and outputs the output signals in the order of the output signal of the Hall element 18 from the output signal of the Hall element 11 (in order). Here, “in order” or “sequentially (sequentially)” or “in order” means “in time series” or “selectively one by one from a plurality”.

In the present embodiment, the switching control unit 41, the switch unit 2, and the A / D conversion unit 3 correspond to the signal generation unit 30.
The signal generation unit 30 generates the above-described a-cycle processing signal (eg, fundamental wave signal) based on the eight output signals (detection signals) output from the eight Hall elements 11 to 18. That is, the signal generation unit 30 causes the switch unit 2 to sequentially output eight Hall elements 10 that output an output signal of nine cycles by rotating the rotor 6 once, and a cycle (a = 1). A processing signal (eg, fundamental wave signal) is generated. Here, for example, the signal generation unit 30 uses the aliasing in the discrete Fourier transform described above, thereby converting the nine periodic signals (m = 9) into eight periodic signals (n = 8) as one period (n = 8). A processed signal of a = 1) is generated. The signal generation unit 30 outputs the generated processing signal of one cycle (a = 1) to the signal processing unit 4. Further, the signal generation unit 30 generates an a-cycle processed signal using aliasing in the discrete Fourier transform based on the above-described m cycles and n.

The position detection unit 42 (detection unit) detects the position information of the rotor 6 based on the a-cycle processing signal (here, the fundamental wave signal) generated by the signal generation unit 30. For example, the position detection unit 42 generates Fourier coefficients (a ₁ , b ₁ ) of the order (eg, first order) corresponding to the a period based on the processing signal of the a period, and generates the generated Fourier coefficients (a ₁ , Based on b ₁ ), position information of the rotor 6 (for example, a rotation angle θ) is detected. Note that the rotation angle θ in the present embodiment is an electrical angle, and is information obtained by interpolating a mechanical angle of 40 ° (= 360/9) as 360 °. The position detector 42 counts each time the rotor 6 moves (rotates) by one pole (mechanical angle 40 °), and positions the counted value (count value) and the rotation angle θ (interpolation information) described above. It may be generated as information. The position detector 42 outputs the generated position information (rotation angle θ) to the outside of the encoder 1. Here, a method for detecting position information based on Fourier coefficients (a ₁ , b ₁ ) is referred to as an “inverse Fourier transform method”.
The position detection unit 42 includes a Fourier coefficient generation unit 421 and a position information generation unit 422.

The Fourier coefficient generation unit 421, for example, based on eight output signals in the processing signal of a period, the order (for example, primary (fundamental wave)) Fourier coefficient (a ₁ , b ₁ ) corresponding to the a period. Is generated. The Fourier coefficient generation unit 421 outputs the generated Fourier coefficient to the position information generation unit 422.

The position information generator 422 detects the position information of the rotor 6 based on the Fourier coefficients (a ₁ , b ₁ ) generated by the Fourier coefficient generator 421.
An example of a method for generating position information of the rotor 6 by the position detection unit 42 (Fourier coefficient generation unit 421 and position information generation unit 422) will be described later.

Next, the operation of the encoder 1 in this embodiment will be described.
First, the operation of the signal generation unit 30 will be described.
FIG. 3 is a diagram showing an output waveform of the magnetic sensor unit 20 in the present embodiment.
In FIG. 3, a waveform W1 represents an output waveform of one Hall element 10 (eg, Hall element 11) when the rotor 6 is rotated once, for example. As shown in the waveform W <b> 1, each Hall element 10 outputs a periodic signal with m periods (m = 9) equal to the number of magnetic poles of the magnet 5 by one rotation of the rotor 6.

Outputs MS1 to MS8 indicate output signals corresponding to the Hall elements 11 to 18 when the rotor 6 is stationary. The signal generation unit 30 switches the eight output signals in a predetermined order and sequentially outputs them from the switch unit 2, and based on the sequential output signals output from the switch unit 2, a cycle (a = The processing signal (fundamental wave signal) of 1) is generated. That is, the switching control unit 41 outputs a control signal and sequentially outputs the output signals of the Hall elements 11 to 18 to the switch unit 2 by switching the output signals of the Hall elements 11 to 18 in, for example, clockwise order ( (Sequential output). In this way, the signal generation unit 30 switches the eight output signals in a predetermined order and sequentially outputs them from the switch unit 2, and based on the sequential output signals output from the switch unit 2, a cycle (e.g., a = The processing signal of 1) is generated. This waveform W2 is obtained by detecting the output signal of 9 cycles by the 8 Hall elements 10. As a result, aliasing in the discrete Fourier transform occurs, so that a processed signal (fundamental wave) of 1 cycle was observed. Looks like.
In the present embodiment, the signal generation unit 30 converts the processing signal (fundamental wave signal) of a cycle (a = 1) as a digital value of the outputs MS1 to MS8 via the A / D conversion unit 3. Output to 42.

  Here, the above-described outputs MS1 to MS8 are expressed as the following formula (1).

  As shown in Expression (1), the eight Hall elements 11 to 18 have different phases divided by a period (a = 1) (for example, π (pi) / 4 = 45 ° shifted from each other). It is arranged so that eight output signals can be obtained. Here, the phase difference (π / 4) of each output signal is, for example, the displacement range (1 rotation = 2π) of the rotor 6 in which the m period described above is obtained, and the number n (n = 8) of the Hall elements 10. The value divided by.

  As described above, the encoder 1 in the present embodiment can generate a fundamental processing signal (waveform W2) from a periodic signal of m periods (m = 9) by using aliasing in discrete Fourier transform. . In this case, the outputs MS1 to MS8 can acquire signals having electrical angles of 0 °, 45 °, 90 °, 135 °, 180 °, 225 °, 270 °, and 315 °. The processing signal (waveform W2) obtained by this aliasing has a mechanical angle of 40 ° and an electrical angle of 360 ° (changes by one cycle). That is, the encoder 1 in the present embodiment is an incremental encoder.

Next, the operation of the position detection unit 42 in the present embodiment will be described.
<Position detection operation by inverse Fourier transform method>
The Fourier coefficient generation unit 421 of the position detection unit 42 is based on the outputs MS1 to MS8 output from the signal generation unit 30 as processing signals (fundamental wave signals) of one cycle, and the fundamental wave Fourier coefficients (a ₁ , b _1). ) Is generated.
The Fourier coefficient generation unit 421 generates a fundamental wave Fourier coefficient a ₁ based on the following equation (2).

Here, f1 (θ) to f8 (θ) in Expression (2) correspond to the outputs MS1 to MS8 in Expression (1). Further, cos (0), cos (π / 4), cos (2π / 4), cos (3π / 4), cos (4π / 4), cos (5π / 4), cos (6π) in the formula (2) / 4) and cos (7π / 4) are constants used in calculating the Fourier coefficient a ₁ .

  Further, the Fourier coefficient generation unit 421 generates a fundamental wave Fourier coefficient b1 based on the following equation (3).

Here, f1 (θ) to f8 (θ) in Expression (3) correspond to the outputs MS1 to MS8 of Expression (1). Further, cos (0), sin (π / 4), sin (2π / 4), sin (3π / 4), sin (4π / 4), sin (5π / 4), sin (6π) in the expression (3). / 4) and sin (7π / 4) are constants used in calculating the Fourier coefficient b ₁ .
As an example, “4” in Expression (2) and Expression (3) uses a value obtained by dividing the number “8” of the Hall elements 10 by “2”, but it is not always necessary to use “4”. Good.

Next, the position information generation unit 422 is based on the Fourier coefficients (a ₁ , b ₁ ) generated by the Fourier coefficient generation unit 421 and the following expression (4), and the position information (rotation angle 9θ) of the rotor 6. Is detected as phase information of the fundamental wave.

Next, reduction of the distortion component of the encoder 1 in the present embodiment will be described.
For example, when the rotor 6 (disk 61) has a third-order distortion component, the output signal of the Hall element 10 when the rotor 6 rotates once changes as shown by a waveform W3 in FIG. The waveform W3 is a signal including a third-order distortion component, and the waveform W4 generated by the signal generation unit 30 based on the eight outputs MS1 to MS8 is also a processing signal including a third-order distortion component. . However, the encoder 1 in the present embodiment can separate and process the fundamental wave signal (waveform W5 in FIG. 4) and the third-order distortion component (waveform W6 in FIG. 4). That is, the position detection unit 42 processes only the fundamental wave component by the above-described inverse Fourier transform method, and the third order component is out of the processing band. Therefore, the encoder 1 in the present embodiment can reduce distortion components caused by the rotor 6 (disk 61) and the like. Thus, since the encoder 1 in this embodiment uses discrete Fourier transform, it is possible to reduce the influence of higher-order (harmonic) distortion.

As described above, in the encoder 1 according to the present embodiment, n (for example, n = 8) Hall elements 10 have m periods of a periodic signal (where m is an integer of 2 or more, for example, m = 9). In the displacement range of the rotor 6 where n is obtained, n of different phases obtained by equally dividing a period (where | a | = (m−k × n), k is an integer of 1 or more, for example, a = 1). It arrange | positions so that an output signal may be obtained. The n Hall elements 10 output periodic signals according to the position information of the rotor 6. The signal generation unit 30 generates an a-cycle processing signal based on the n output signals output from the n Hall elements 10. Then, the position detection unit 42 detects the position information of the rotor 6 based on the processing signal (for example, the fundamental wave signal) of a cycle generated by the signal generation unit 30.
Accordingly, the encoder 1 according to the present embodiment executes position detection processing as a processing signal of a cycle lower than m cycles, based on the periodic signal of m cycles, using aliasing in discrete Fourier transform. Therefore, the encoder 1 in the present embodiment can detect position information with high accuracy.

For example, when the processing signal of a cycle is a fundamental wave signal (a = 1), the encoder 1 in this embodiment uses a conventional processing circuit that detects position information from the fundamental wave signal as it is, and has m cycles. The position information can be detected with the resolution of. From this, the encoder 1 in this embodiment can detect position information with high accuracy by signal processing using simple means.
In addition, the encoder 1 according to the present embodiment uses the aliasing in the discrete Fourier transform to detect the position information based on the low-order a-cycle processing signal, so that the high-order distortion component is out of the processing band. Can do. Therefore, the encoder 1 in the present embodiment can reduce position information errors caused by distortion components such as the disk 61, for example. Therefore, the encoder 1 in the present embodiment can detect position information with high accuracy.

In the present embodiment, the m period is larger than half of the number n of the Hall elements 10.
Thereby, the encoder 1 according to the present embodiment can easily generate a processed signal having a period lower than m periods by aliasing.

In the present embodiment, the n Hall elements 10 are equally arranged in the displacement range of the rotor 6 in which m cycles can be obtained. For example, eight Hall elements 11 to 18 are equally arranged in the range of one rotation of the rotor 6 in which nine cycles are obtained.
Thereby, the encoder 1 in the present embodiment can obtain n (for example, 8) output signals having different phases obtained by equally dividing the period a by simple means. Therefore, the encoder 1 in the present embodiment can detect position information with high accuracy.

In the present embodiment, the n Hall elements 10 are arranged so that n output signals having the same phase difference can be obtained in the displacement range of the rotor 6 in which m cycles can be obtained. For example, the eight Hall elements 11 to 18 are arranged so that eight output signals having a phase difference of 45 ° are obtained in the range of one rotation of the rotor 6.
Thereby, the encoder 1 in the present embodiment can obtain n (for example, 8) output signals having different phases obtained by equally dividing the period a by simple means. Therefore, the encoder 1 in the present embodiment can detect position information with high accuracy.

In the present embodiment, the m period (eg, 9 periods) is equal to the number of cycles of the periodic signal in the displacement range (eg, 1 rotation range) of the rotor 6. That is, the m period is equal to the spatial frequency and equal to the number of magnetic poles of the magnet 5.
Thereby, the encoder 1 in the present embodiment can easily change the m cycle. Therefore, the encoder 1 in the present embodiment can appropriately set the m cycle, the number n of the Hall elements 19 and the order (a cycle) of the processing signal by a simple method.

Further, in the present embodiment, the position detection unit 42 uses the Fourier coefficient (a ₁ , b ₁ ) of the order (eg, first order) corresponding to the a period based on the processing signal (eg, fundamental wave signal) of the a period. And position information of the rotor 6 is detected based on the generated Fourier coefficient.
Thereby, the encoder 1 in this embodiment can detect position information correctly with a simple configuration. Therefore, the encoder 1 in the present embodiment can detect position information with high accuracy.

Further, in the present embodiment, the signal generation unit 30 includes the switch unit 2 that sequentially switches and outputs n (for example, 8) output signals in a predetermined order, and outputs the sequential output signals output from the switch unit 2. Based on this, a processing signal of a cycle is generated.
Thereby, the encoder 1 in the present embodiment can generate an a-cycle processing signal from an m-cycle signal with a simple configuration.

Next, a second embodiment will be described with reference to the drawings.
[Second Embodiment]
The encoder 1 in the first embodiment has been described for detecting position information using an inverse Fourier transform method, but the encoder 1a in the present embodiment uses a phase modulation method (sequential ejection method), which will be described later. A case where information is detected will be described.

The arrangement of the Hall element 10 and the number of magnetic poles of the magnet 5 in this embodiment are the same as those of the encoder 1 in the first embodiment shown in FIG.
FIG. 5 is a block diagram showing a configuration of the encoder 1a in the present embodiment.
In FIG. 5, the encoder 1a includes a magnetic sensor unit 20, a switch unit 2, an A / D conversion unit 3, and a signal processing unit 4a. Here, the magnetic sensor unit 20 has eight Hall elements 11 to 18. In the present embodiment, the configuration of the signal processing unit 4a is the same as that of the first embodiment, except that the configuration is different from that of the encoder 1 in the first embodiment. In this figure, the same components as those in FIG. 2 are denoted by the same reference numerals, and the description thereof is omitted.

The signal processing unit 4a includes a switching control unit 41 and a position detection unit 42a.
The position detection unit 42 a (detection unit) detects the position information of the rotor 6 based on the processing signal (a fundamental wave signal in this case) generated by the signal generation unit 30. The position detection unit 42a detects position information (for example, a rotation angle θ) as a phase displacement between the processing signal of the period a and the reference signal (synchronization signal) of the processing signal using the phase modulation method. Note that the rotation angle θ in the present embodiment is an electrical angle, and is information obtained by interpolating a mechanical angle of 40 ° (= 360/9) as 360 °. The position detector 42a counts each time the rotor 6 moves (rotates) by one pole (mechanical angle 36 °), and the counted value (count value) and the rotation angle θ (interpolation information) described above are positioned. It may be generated as information.
The position detection unit 42 a includes a filter unit 423 and a phase detection unit 424.

  The filter unit 423 outputs a detection signal obtained by sequentially outputting the Hall elements 11 to 18 that are processing signals of the period a (eg, a = 1) generated by the signal generation unit 30 to a predetermined frequency including a first-order sine wave. The band is passed and converted into a first-order sine wave signal (fundamental wave signal). That is, the filter unit 423 removes (reduces) higher-order components of the fundamental wave signal from the detection signals (a-cycle processed signals) obtained by sequentially outputting the Hall elements 11 to 18, and converts the fundamental wave signal components. It outputs to the phase detection part 424 as a detection signal.

  The phase detection unit 424 uses a detection signal that is a primary sine wave signal output from the filter unit 423 and uses a method of synchronous detection, phase synchronization, or zero cross point position measurement to generate a reference signal (synchronization signal). Is detected as position information (phase modulation method). The phase detector 424 outputs the generated position information (rotation angle θ) to the outside of the encoder 1a.

Next, the operation of the encoder 1a in this embodiment will be described.
The operation of the signal generation unit 30 in the present embodiment is the same as that in the first embodiment described above. The signal generation unit 30 sequentially outputs eight Hall elements 11 to 18 that output an m-cycle signal and generates an a-cycle processing signal.

  In addition, as described above, the position detection unit 42a detects position information (for example, rotation) as a phase shift between the a-cycle processing signal generated by the signal generation unit 30 and the reference signal (synchronization signal) of the processing signal. Angle θ) is detected. In the position detection unit 42a, for example, the filter unit 423 removes (reduces) the higher-order component of the fundamental wave signal from the a-cycle processed signal), and uses the component of the fundamental wave signal as the detection signal, and the phase detection unit 424. The phase detector 424 detects the phase value (rotation angle θ) with respect to the reference signal (synchronization signal) as position information by the phase modulation method.

  In addition, since the fundamental wave signal is separated and processed by the filter unit 423 to reduce the distortion component of the encoder 1a in the present embodiment, the influence of harmonic distortion is reduced as in the first embodiment. Can do.

As described above, in the encoder 1a in the present embodiment, the position detection unit 42a uses the position information as the phase displacement between the processing signal (eg, fundamental wave signal) of the period a and the reference signal of the processing signal. To detect.
Thereby, the encoder 1a in this embodiment can detect position information correctly with a simple configuration as in the case of the inverse Fourier transform method in the first embodiment. Therefore, the encoder 1a in this embodiment can detect position information with high accuracy.

Next, a third embodiment will be described with reference to the drawings.
[Third Embodiment]
An encoder 1b according to the third embodiment will be described with an example including a correction unit 43 that performs correction processing when the Hall element 10 is misaligned.

The arrangement of the Hall element 10 and the number of magnetic poles of the magnet 5 in this embodiment are the same as those of the encoder 1 in the first embodiment shown in FIG.
FIG. 6 is a block diagram showing a configuration of the encoder 1b in the present embodiment.
In FIG. 6, the encoder 1b includes a magnetic sensor unit 20, a switch unit 2, an A / D conversion unit 3, and a signal processing unit 4a. Here, the magnetic sensor unit 20 has eight Hall elements 11 to 18. In the present embodiment, the configuration of the signal processing unit 4b is the same as that of the first embodiment, except that the configuration is different from that of the encoder 1 in the first embodiment. In this figure, the same components as those in FIG. 2 are denoted by the same reference numerals, and the description thereof is omitted.

  The signal processing unit 4b includes a switching control unit 41, a position detection unit 42b, and a correction information storage unit 431. The position detection unit 42b (detection unit) includes a Fourier coefficient generation unit 421a and a position information generation unit 422a. In the present embodiment, the Fourier coefficient generation unit 421a and the correction information storage unit 431 correspond to the correction unit 43.

The correction information storage unit 431 (storage unit) stores correction information used for correction processing in the present embodiment described later. The correction information stored in the correction information storage unit 431 includes, for example, phase value information (eg, 0 °, N phase signals of N phase signals (where N = n) obtained by equally dividing the above-described a cycle (eg, 1 cycle)). π / 4,..., 7π / 4) and N phase signals as reference signals, N phase signals (eg, outputs MS1 to MS8) and n (eg, 8) Hall elements 11 -18 phase signals and respective phase differences. Here, the phase difference between the phase signal and the output signal of the Hall element 10 is caused by a positional deviation of the Hall element 10 that occurs during manufacturing.
The correction information storage unit 431 stores in advance an offset correction value, which will be described later, which is a correction value for correcting the offset error.

  By the way, in the present embodiment, the range of one rotation of the rotor 6 so that N (eight) phase signals obtained by equally dividing the eight hall elements 11 to 18 into the above-described one period are output as output signals. However, in reality, for example, variations (positional deviation) may occur in the arrangement of the eight Hall elements 11 to 18 due to manufacturing variations. This variation in arrangement (positional deviation) can be detected in the output signal of the Hall element 10 as the above-described phase difference. Here, the phase difference between the phase signal and the output signal of the Hall element 10 is, for example, information acquired in advance at the time of manufacturing inspection (shipment inspection).

  The correction unit 43 uses the eight phase signals and the eight output signals with N (eg, eight) phase signals (for example, N = n) obtained by equally dividing the a cycle (eg, one cycle) as reference signals. Based on the respective phase differences from the (outputs MS1 to MS8) and the eight output signals, the eight output signals are respectively corrected so that the eight output signals become eight phase signals. , Generate corrected output information. The correction unit 43 acquires, for example, from the correction information storage unit 431, the phase difference of the eight output signals with respect to the eight phase signals that are predetermined reference signals. The correction unit 43 includes a Fourier coefficient generation unit 431a.

For example, the Fourier coefficient generation unit 421a has an a period based on the eight output signals and the phase value and phase difference of the phase signal corresponding to each of the eight output signals read from the correction information storage unit 431. A Fourier coefficient (a ₁ , b ₁ ) of a corresponding order (for example, primary (fundamental wave)) is generated as corrected output information. The Fourier coefficients generated here are Fourier coefficients corrected so that the eight output signals become eight phase signals, and the Fourier coefficient generation unit 421a corrects the corrected Fourier coefficients. Generate as output information. The Fourier coefficient generation unit 421a outputs the generated Fourier coefficient to the position information generation unit 422a.

The position information generation unit 422a detects the position information of the rotor 6 based on the Fourier coefficients (a ₁ , b ₁ ) generated by the Fourier coefficient generation unit 421a. Here, the Fourier coefficients (a ₁ , b ₁ ) are the above-described corrected output information, and the offset error needs to be corrected in order to generate the final position information of the rotor 6. Therefore, the position information generation unit 422a generates position information in which the offset error is corrected based on the offset correction value read from the correction information storage unit 431.
As described above, the position detection unit 42b is configured to output the position information (for example, the rotation angle) of the rotor 6 based on the corrected output information (for example, Fourier coefficients (a ₁ , b ₁ )) generated by the correction unit 43. θ). Note that the rotation angle θ in the present embodiment is an electrical angle, and is information obtained by interpolating a mechanical angle of 40 ° (= 360/9) as 360 °. The position detection unit 42a counts each time the rotor 6 moves (rotates) by one pole (mechanical angle 40 °), and the counted value (count value) and the rotation angle θ (interpolation information) described above are positioned. It may be generated as information.
An example of a method for generating position information of the rotor 6 will be described later.

Next, the operation of the encoder 1b in this embodiment will be described.
The operation of the signal generation unit 30 in the present embodiment is the same as that in the first embodiment described above. The signal generation unit 30 sequentially outputs eight Hall elements 11 to 18 that output an m-cycle signal and generates an a-cycle processing signal.

  Next, a correction process when the Hall element 10 is displaced in the encoder 1b according to this embodiment will be described. Here, as an example, a case where the position of the Hall element 12 is shifted by δ will be described.

  In this case, outputs MS1 to MS8 of the eight Hall elements 11 to 18 are expressed by the following formula (5). Here, the output MS2 of the Hall element 12 is output as a phase signal shifted by δ.

The Fourier coefficient generation unit 421a of the correction unit 43 (position detection unit 42b) acquires, for example, from the correction information storage unit 431, the phase differences of the eight output signals with respect to the eight phase signals that are predetermined reference signals. Here, in the correction information storage unit 431, the phase value (π / 4) and the phase difference (δ) of the Hall element 12 described above are stored in advance. The Fourier coefficient generation unit 421a is based on the eight output signals (MS1 to MS8) acquired from the A / D conversion unit 3 and the phase value and phase difference of the phase signal read from the correction information storage unit 431. Next (fundamental wave) Fourier coefficients (a ₁ , b ₁ ) are generated based on the following equations (6) and (7).

First, the Fourier coefficient generator 421a generates based on Fourier coefficients _{a 1} in equation (6) below. Here, when the phase value α and the phase difference δ of the phase signal are set, the Fourier coefficient generation unit 421a changes the constant for calculating the Fourier coefficient a ₁ from cos (α) to cos (α−δ). Thus, the Fourier coefficient a ₁ is calculated. In this case, for example, since the phase value α is “π / 4”, the Fourier coefficient generation unit 421a sets a constant corresponding to the output signal MS2 of the Hall element 12 to cos (π / Instead of 4), cos (π / 4-δ) is used to generate the Fourier coefficient a ₁ .

Further, the Fourier coefficient generation unit 421a generates the Fourier coefficient b ₁ based on the following equation (7). Here, the Fourier coefficient generator 421a includes a constant when calculating the Fourier coefficients _{b 1} to change from sin (alpha) to sin (α-δ), to calculate a Fourier coefficient _{b 1.} In this case, for example, since the phase value α is “π / 4”, the Fourier coefficient generation unit 421a sets a constant corresponding to the output signal MS2 of the Hall element 12 as sin (π / Instead of 4), sin (π / 4-δ) is used to generate the Fourier coefficient b ₁ .

In this way, the Fourier coefficient generation unit 421a corrects the eight output signals to be eight phase signals by correcting the constants when calculating the Fourier coefficients (a ₁ , b ₁ ), The Fourier coefficients (a ₁ , b ₁ ) are output to the position information generator 422a as corrected output information. That is, the correcting unit 43 generates Fourier coefficients (a ₁ , b ₁ ) based on the difference value between the phase value α and the phase difference δ of the phase signal.

When position information is generated based on the corrected Fourier coefficients (a ₁ , b ₁ ) generated by the above-described Fourier coefficient generation unit 421a, the generated position information includes an offset error. This offset error (offset amount) is calculated by the following equation (8). Here, in the present embodiment, this offset amount is calculated in advance based on the following equation (8), and is stored in advance in the correction information storage unit 431 as an offset correction value.

Based on the corrected Fourier coefficients (a ₁ , b ₁ ) and the offset correction value read from the correction information storage unit 431, the position information generation unit 422 a calculates the position of the rotor 6 by the following equation (9). Information (rotation angle θ) is generated. The position information generation unit 422a outputs the generated position information (rotation angle θ) to the outside of the encoder 1b.

As described above, the encoder 1b in the present embodiment includes the correction unit 43. The correction unit 43 uses N phase signals (where N = n, for example, 8) equally divided a period (eg, 1 period) as a reference signal, and N phase signals, n output signals, The n output signals are corrected so that the n output signals become N phase signals based on the respective phase differences and the n output signals. The correction unit 43 corrects each of the n output signals and generates corrected output information (eg, Fourier coefficients (a ₁ , b ₁ )). The position detection unit 42 b detects the position information of the rotor 6 based on the corrected output information generated by the correction unit 43.
Thereby, for example, even when the positional deviation of the Hall element 10 occurs, the correction unit 43 corrects the n output signals so that the n output signals become N phase signals, respectively. The encoder 1b in the present embodiment can detect position information with high accuracy.

Further, in the present embodiment, the correction unit 43 (Fourier coefficient generation unit 421a), based on the difference value (α−δ) between the phase value α and the phase difference δ of the phase signal, Fourier coefficients (a ₁ , b _1). ) Is generated. That is, the correction unit 43 converts the constants into cos (α−δ) and sin (α−δ), for example, according to the equations (6) and (7), and the Fourier coefficients (a ₁ , b ₁ ). Generate.
Thereby, the encoder 1b in this embodiment can correct | amend the error based on the shift | offset | difference of the phase signal by the position shift of the Hall element 10, etc. by a simple means. Therefore, the encoder 1b in the present embodiment can detect the position information with high accuracy by a simple means.

Next, a fourth embodiment will be described with reference to the drawings.
[Fourth Embodiment]
The arrangement of the Hall element 10 and the number of magnetic poles of the magnet 5 in this embodiment are the same as those of the encoder 1 in the first embodiment shown in FIG.
FIG. 7 is a block diagram showing a configuration of the encoder 1c in the present embodiment.
In FIG. 7, the encoder 1 c includes a magnetic sensor unit 20, a switch unit 2, an A / D conversion unit 3, a signal processing unit 4, and a gain adjustment unit 50. Here, the magnetic sensor unit 20 has eight Hall elements 11 to 18. In the present embodiment, the point that the gain adjustment unit 50 is provided is different from the encoder 1 in the first embodiment, and other configurations are the same as those in the first embodiment. In this figure, the same components as those in FIG. 2 are denoted by the same reference numerals, and the description thereof is omitted.

The gain adjustment unit 50 (adjustment unit) is, for example, a gain adjustment type amplifier circuit (amplifier), and adjusts the signal levels of the eight output signals output from the eight hall elements 11 to 18. . For example, the gain adjusting unit 50 adjusts the eight output signals so that the output characteristics of the eight output signals are matched. Here, the output characteristics of the output signal are the amplitude, maximum signal level, minimum signal level, DC offset value, etc. of the output signal. The gain adjusting unit 50 outputs the adjusted eight output signals to the switch unit 2.
In the present embodiment, the operations after the switch unit 2 are the same as those in the first embodiment described above, and a description thereof is omitted here.

As described above, the encoder 1c in the present embodiment includes the gain adjusting unit 50 that adjusts the signal level of n output signals output from n (for example, n = 8) Hall elements 10. Yes.
Thereby, the variation in the output level of the Hall element 10 can be reduced. Therefore, the encoder 1c in this embodiment can reduce an error more than the first embodiment. Therefore, the encoder 1c in this embodiment can detect position information with high accuracy.

Next, a fifth embodiment will be described with reference to the drawings.
[Fifth Embodiment]
In this embodiment, an example will be described in which the present invention is applied to an absolute encoder that detects absolute position information using two incremental encoders similar to those in the first embodiment.

FIG. 8 is a schematic configuration diagram illustrating an example of the configuration of the encoder 1d according to the present embodiment.
Here, FIG. 8A shows a front view of the encoder 1d viewed from the rotation axis direction (Z-axis direction) of the rotor 6, and FIG. 8B shows a cross section of the encoder 1d along the line AA ′. The figure is shown.

  In FIG. 8, an encoder 1d includes a rotor 6 having a disk 61, n1 (for example, eight) Hall elements 111 to 118, n2 (for example, nine) Hall elements 121 to 129, and And a substrate 7 on which Hall elements (111 to 118, 121 to 129) and other control components are mounted.

  The disc 61 (code plate) includes a magnet 51 (9-pole multipole magnet) and a magnet 52 (10-pole multipole magnet). Here, the magnet 51 (9-pole multipole magnet) has a m1 period (eg, 9 periods) periodic signal in the predetermined displacement range (eg, 1 rotation) of the rotor 6 as described above. Corresponds to the magnetic pole pattern (first pattern) obtained as follows. In addition, the magnet 52 (10-pole multipole magnet) has a m2 period (eg, 10 periods) periodic signal as the above-described m period periodic signal within a predetermined displacement range (eg, 1 revolution) of the rotor 6. This corresponds to the obtained magnetic pole pattern (second pattern).

The magnet 51 is a permanent magnet having nine pairs of S poles 5S and N poles 5N (9 poles in one circumference of the rotor 6). The magnet 51 is disposed on the circumference of the rotor 6 in contact with the donut-shaped groove (first groove) of the disk 61.
Further, the magnet 52 is a permanent magnet having 10 pairs of S poles 5S and N poles 5N (10 poles in one circumference of the rotor 6). The magnet 52 is disposed on the circumference of the rotor 6 in contact with the donut-shaped groove (second groove) of the disk 61.
The magnet 51 is disposed on the inner circumference of the disk 61, and the magnet 52 is disposed on the outer circumference of the disk 61.

  The eight Hall elements 111 to 118 are arranged on the circumference of the rotor 6 at positions near the magnet 51 (for example, positions near the inside of the magnet 51). The nine Hall elements 121 to 129 are arranged on the circumference of the rotor 6 at positions near the magnet 52 (for example, positions near the outside of the magnet 52). Here, the position near the magnet 51 is, for example, around the magnet 51 and includes a position sufficient for the Hall elements 111 to 118 to detect a change in magnetic field strength caused by the magnet 51. Further, the position near the magnet 52 is, for example, the periphery of the magnet 52 and includes a position sufficient for the Hall elements 121 to 129 to detect a change in magnetic field strength caused by the magnet 52.

The Hall elements 111 to 118 are arranged so as to face the magnet 51 on the circumference that is equidistant from the rotation axis of the rotor 6 in the above-mentioned donut-shaped groove (first groove). The eight Hall elements 111 to 118 each output a periodic signal according to position information of the rotor 6 (driven body). In addition, the eight Hall elements 111 to 118, for example, have eight output signals with different phases obtained by equally dividing the a1 period in the displacement range of the rotor 6 where the m1 period of the periodic signal described above is obtained. It arrange | positions so that it may be obtained based on the magnetic pole pattern of the magnet 51. FIG. However, | a1 | = (m1−k × n1), k is an integer of 1 or more, and m1 is an integer of 2 or more. Further, n1 is the number of Hall elements 10, and here, n1 = 8. Further, the a1 period is an integer, and when the value of a1 is negative, it indicates that the phase of the processing signal that appears by aliasing in the discrete Fourier transform is rotated by 180 °.
Further, the eight Hall elements 111 to 118 have, for example, the same detection sensitivity, and each have the same output level.

The Hall elements 121 to 129 are arranged so as to face the magnet 52 on the circumference that is equidistant from the rotation axis of the rotor 6 in the above-described donut-shaped groove (second groove). The nine Hall elements 121 to 129 each output a periodic signal according to the position information of the rotor 6 (driven body). In addition, the nine Hall elements 121 to 129 have nine output signals with different phases obtained by equally dividing the a2 period, for example, in the displacement range of the rotor 6 in which the m2 period of the periodic signal described above is obtained. It arrange | positions so that it may be obtained based on the magnetic pole pattern of the magnet 51. FIG. However, | a2 | = (m2−k × n2), k is an integer of 1 or more, and m2 is an integer of 2 or more. N2 is the number of Hall elements 10, and here, n2 = 9. Further, the a2 cycle is an integer, and when the value of a2 is negative, it indicates that the phase of the processing signal that appears in the aliasing in the discrete Fourier transform is rotated by 180 °.
The nine Hall elements 121 to 129 have, for example, the same detection sensitivity, and each have the same output level.

In the present embodiment, since the a1 period and the a2 period are one period, the processing signal for detecting position information is a processing signal (fundamental wave (primary) signal) of one period.
Further, in the case where any Hall element among the Hall elements 111 to 118 and the Hall elements 121 to 129 or a Hall element included in the encoder 1 is simply indicated, it will be referred to as a Hall element 10 and will be described below. Further, in the present embodiment, the constituent parts showing the whole Hall elements 111 to 118 correspond to the sensor group 21 (first detection element group), and the constituent parts showing the whole Hall elements 121 to 129 are the sensor group. 22 (second detection element group).
Thus, the encoder 1d is a vernier type absolute encoder including the two systems of magnets (51, 52) and the sensor groups (21, 22) similar to those of the first embodiment using discrete Fourier transform aliasing. .

FIG. 9 is a block diagram showing the configuration of the encoder 1d in the present embodiment.
In FIG. 9, the encoder 1c includes a magnetic sensor unit 20a, a switch unit (2A, 2B), an A / D conversion unit (3A, 3B), and a signal processing unit 4c. Here, the magnetic sensor unit 20a includes the sensor group 21 and the sensor group 22 described above.
The signal processing unit 4c includes a switching control unit 41a and a position detection unit 42c.

In the present embodiment, the switch units (2A, 2B) have the same configuration as that of the switch unit 2 in the first embodiment, and the A / D conversion units (3A, 3B) have the A / D in the first embodiment. The configuration is the same as that of the D conversion unit 3.
The switching control unit 41a is different from the switching control unit 41 in the first embodiment in that it controls switching of the two switch units (2A, 2B), but the basic functions are the same.
Here, the switching control unit 41a, the switch units (2A, 2B), and the A / D conversion units (3A, 3B) correspond to the signal generation unit 30a.

  The signal generation unit 30a generates a processing signal having an a1 period (eg, a1 = 1) based on n1 (eg, n1 = 8) output signals output from the sensor group 21, and the sensor group 22 outputs the processed signal. Based on n2 (eg, n2 = 9) output signals, a processing signal having a2 period (eg, a2 = 1) is generated. The signal generation unit 30a outputs a processing signal (fundamental wave signal) having an a1 period (e.g., a1 = 1) to the position detection unit 42c as a digital value of the outputs MS11 to MS18 via the A / D conversion unit 3A. In addition, the signal generation unit 30a outputs a processing signal (fundamental wave signal) of a2 period (eg, a1 = 1) to the position detection unit 42c as a digital value of the outputs MS21 to MS29 via the A / D conversion unit 3B. To do.

  Here, the outputs MS11 to MS18 corresponding to the output signals of the Hall elements 111 to 118 are represented by the following formula (10).

  Outputs MS21 to MS19 corresponding to the output signals of the Hall elements 121 to 129 are represented by the following formula (11).

  The position detection unit 42c (detection unit) detects position information indicating the absolute position of the rotor 6 based on the a1 period processing signal and the a2 period processing signal generated by the signal generation unit 30a. In the present embodiment, both the a1 period processing signal and the a2 period processing signal are fundamental wave signals. In the present embodiment, an example in which the position detection unit 42c detects position information using an inverse Fourier transform method will be described, as in the first embodiment. The position detection unit 42c includes a Fourier coefficient generation unit 421b and a position information generation unit 422b.

The Fourier coefficient generation unit 421b, based on the eight output signals (outputs MS11 to MS18) in the processing signal of the a1 period, the Fourier coefficient (a ₁ ) of the order (for example, the first order (fundamental wave)) corresponding to the a1 period. , B ₁ ). The Fourier coefficient generation unit 421b outputs the generated Fourier coefficient to the position information generation unit 422b.
Further, the Fourier coefficient generation unit 421b, based on the nine output signals (MS21 to MS29) in the processing signal of the a2 period, the Fourier coefficient (a of the first order (fundamental wave)) corresponding to the a2 period (a ₁ , b ₁ ). The Fourier coefficient generation unit 421b outputs the generated Fourier coefficient to the position information generation unit 422b.

The position information generation unit 422b detects the position information of the rotor 6 based on the two systems of Fourier coefficients (a ₁ , b ₁ ) generated by the Fourier coefficient generation unit 421b. That is, the position information generating unit 422b, based on the Fourier coefficients based on the processing signal a1 period _{(a 1, b} 1), the Fourier coefficients based on the processing signal a2 period as _{(a 1, b} 1), a rotor Position information (rotation angle θ) indicating the absolute position 6 is detected.

For example, the Fourier coefficient generation unit 421b generates Fourier coefficients (a ₁ , b ₁ ) based on the processed signal of the a1 period by the following formulas (12) and (13).

The position information generation unit 422b uses the Fourier coefficients (a ₁ , b ₁ ) based on the a1 period processed signal generated by the Fourier coefficient generation unit 421b to generate position information ( 1st position information) is generated. The first position information (rotation angle 9θ) is position information detected based on the output signal of the sensor group 21.

Further, the Fourier coefficient generation unit 421b generates Fourier coefficients (a ₁ , b ₁ ) based on the processing signal of the a2 period, for example, by the following formulas (15) and (16).

The position information generation unit 422b uses the Fourier coefficients (a ₁ , b ₁ ) based on the a2 period processing signal generated by the Fourier coefficient generation unit 421b to generate position information ( Second position information) is generated. The second position information (rotation angle 10θ) is position information detected based on the output signal of the sensor group 22.

  Based on the first position information (rotation angle 9θ) and the second position information (rotation angle 10θ), the position information generation unit 422b uses the following formula (18) as position information (rotation angle) as absolute position information. θ) is detected.

  As described above, the position information generation unit 422b has a difference between the first position information detected based on the output signal of the sensor group 21 and the second position information detected based on the output signal of the sensor group 22. To generate absolute position information. That is, the encoder 1d realizes a vernier absolute encoder by comparing the phase information detected by the two sensor groups (21, 22) as described above.

As described above, in the encoder 1d according to the present embodiment, the disk 61 has a m1 period (e.g., 9 periods) periodic signal within the predetermined displacement range (e.g., 1 rotation) of the rotor 6 as described above. A first pattern (eg, a 9-pole magnetic pattern) obtained as a periodic signal of a period and a second signal obtained as an m-periodic signal described above are m2 periods (eg, 10 periods) different from the m1 period. Pattern (10-pole magnetic pattern).
The sensor group 21 includes n1 (e.g., eight) Hall elements 111 to 118 as the n Hall elements 10 described above. Here, in the predetermined displacement range, the n1 Hall elements 111 to 118 have n1 output signals having different phases obtained by equally dividing the a1 period (e.g., one period) as the above-described a period. It is arranged to be obtained based on the pattern.

The sensor group 22 includes n2 (for example, 9) Hall elements 121 to 129 as the n Hall elements 10 described above. Here, the n2 Hall elements 121 to 129 have n2 output signals of different phases obtained by equally dividing the a2 period (e.g., one period) as the above-described a period in the predetermined displacement range. It is arranged to be obtained based on the pattern.
The signal generation unit 30a generates an a1 period processing signal based on the n1 output signals output from the sensor group 21, and generates an a2 period processing signal based on the n2 output signals output from the sensor group 22. Generate. The position detection unit 42c detects position information indicating the absolute position of the rotor 6 based on the a1 period processing signal and the a2 period processing signal generated by the signal generation unit 30a.
Thereby, the encoder 1d in the present embodiment can detect the position information with high accuracy and can detect the position information as absolute position information, as in the first embodiment.

[Sixth Embodiment]
Next, a driving device (motor device, actuator) including the encoder 1 (1a to 1d) in the above-described embodiment will be described.
FIG. 10 is a schematic diagram of the driving device DR in the present embodiment. The drive device DR in the present embodiment includes a motor MTR that rotates the input shaft IAX, and an encoder 1 (1a to 1d) provided on the input shaft IAX (rotor 6). That is, the driving device DR includes an encoder 1 (1a to 1d) and a motor MTR (driving unit) that drives the input shaft IAX (driven body).

  The encoder 1 (1a to 1d) detects the rotational position (angular position) of the input shaft IAX (driven body), and uses the positional information including the rotational position as an encoder signal for a host controller that controls the driving device DR. Output. The host controller controls the driving device DR based on the encoder signal received from the encoder 1 (1a to 1d). Since the encoder 1 (1a-1d) in this embodiment can detect a rotational position with high precision, the drive device DR in this embodiment can position-control the input shaft IAX of the motor MTR with high precision.

  In addition, as shown in FIG. 11, the drive device DR in the present embodiment may have a configuration in which a reduction gear RG (eg, a planetary gear mechanism) is provided on the input shaft IAX of the motor MTR. In this case, the encoder 1 (1a to 1d) in the present embodiment may be arranged on the output shaft OAX of the reduction gear RG, or between the input shaft IAX of the motor MTR and the output shaft OAX of the reduction gear RG. You may make it arrange | position to both.

The present invention is not limited to the above embodiments, and can be modified without departing from the spirit of the present invention.
Hereinafter, modifications of the above embodiments will be described.

<First Modification>
In the first modification, an example will be described in which the number a of processing signal periods is “2” in the first embodiment described above.
FIG. 12 is a schematic configuration diagram showing the configuration of the encoder 1e according to the first modification.
Here, FIG. 12A shows a front view of the encoder 1e viewed from the rotation axis direction (Z-axis direction) of the rotor 6, and FIG. 12B shows a cross section of the encoder 1e along the line AA ′. The figure is shown. 12, the same components as those in FIG. 1 are denoted by the same reference numerals, and the description thereof is omitted.

  In the first modification, the encoder 1e is different from the first embodiment in that it includes a magnet 5a that is a 10-pole multipolar magnet instead of the magnet 5. In this case, since the magnet 5a is a 10-pole multipolar magnet, the above-mentioned m-cycle periodic signal is a 10-cycle periodic signal, and the a-cycle processed signal is 2 cycles (| a | = (10− The processing signal is 1 × 8) = 2).

FIG. 13 is a diagram showing an output waveform of the magnetic sensor unit 20 in the first modification.
In FIG. 13, a waveform W7 indicates an output waveform of one Hall element 10 (eg, Hall element 11) when the rotor 6 is rotated once, for example. As shown in the waveform W7, each Hall element 10 outputs a periodic signal of m periods (m = 10) equal to the number of magnetic poles of the magnet 5a by one rotation of the rotor 6.

  Outputs MS1 to MS8 indicate output signals corresponding to the Hall elements 11 to 18 when the rotor 6 is stationary. In the signal generation unit 30, the switch unit 2 switches the eight output signals in a predetermined order and sequentially outputs them. Based on the sequential output signal output from the switch unit 2, the a cycle (a = 2) of the processing signal (secondary processing signal) is generated. In this case, the point that the Fourier coefficient generation unit 421 generates a second-order Fourier coefficient is different from the first embodiment, but the other processes are the same as those of the first embodiment.

  Thus, the order of the processed signal is not limited to the first order, but may be the second order as described above, or may be a form using a third order or higher order.

Next, a second modification will be described.
<Second Modification>
In the second modified example, in the first embodiment described above, the displacement range of the rotor 6 in which the m period is obtained is a partial range of the entire displacement range of the rotor 6 (for example, one rotation). An example will be described. That is, in the second modification, an example in which the arrangement range of the magnetic sensor unit 20 is not the entire circumference will be described.

FIG. 14 is a schematic configuration diagram illustrating a configuration of an encoder 1f according to a second modification.
Here, FIG. 14A shows a front view of the encoder 1f viewed from the rotation axis direction (Z-axis direction) of the rotor 6, and FIG. 14B shows a cross section of the encoder 1f along the line AA ′. The figure is shown. 14, the same components as those in FIG. 1 are denoted by the same reference numerals, and the description thereof is omitted.

  In the second modification, the encoder 1 f includes a magnet 5 b and a magnetic sensor unit 20 a (Hall elements 11 to 19), which are 40-pole multipolar magnets, instead of the magnet 5 and the magnetic sensor unit 20. Different from the first embodiment. Here, the nine (n = 9) Hall elements 11 to 19 are equally arranged in a range of 10 poles (range of 90 ° mechanical angle) of the magnetic pole pattern. In this case, the periodic signal of m period is a periodic signal of 10 periods, and the processed signal of a period is a processed signal of 1 period (| a | = (10−1 × 9) = 2).

FIG. 15 is a diagram illustrating an output waveform of the magnetic sensor unit 20a in the second modification.
In FIG. 15, a waveform W9 indicates an output waveform of one Hall element 10 (eg, Hall element 11) when the rotor 6 is rotated by 90 °, for example. As shown in the waveform W9, each Hall element 10 outputs a periodic signal of m period (m = 10) equal to the number of magnetic poles in the 90 ° range of the magnet 5b by the 90 ° rotation of the rotor 6.

  Outputs MS1 to MS9 indicate output signals corresponding to the Hall elements 11 to 19 when the rotor 6 is stationary. In this case, in the signal generation unit 30, the switch unit 2 switches the nine output signals in a predetermined order and sequentially outputs them, and based on the sequential output signal output from the switch unit 2, the a cycle as shown in the waveform W10 A processing signal (fundamental wave signal) of (a = 1) is generated. Here, the processing signal indicated by the waveform W10 is a signal in which the electrical angle is displaced by 360 ° (changed by one cycle) with respect to the mechanical angle of 9 ° (= 360 ° / 40). Subsequent processing is the same as in the first embodiment.

  As described above, the displacement range of the rotor 6 in which m cycles can be obtained is not limited to the entire displacement range (for example, one rotation) of the rotor 6, but a partial range (for example, the entire displacement range). , 90 °).

In each of the above embodiments, the encoder 1 (1a to 1f) is a magnetic encoder. However, the present invention is not limited to this. For example, an optical type, a contact type, a capacitance type, An electromagnetic induction type encoder may be used.
Hereinafter, modified examples of the third to sixth modified examples applied to an optical encoder will be described.

<Third Modification>
In the third modification, an example in which the above-described first embodiment is applied to an optical encoder is shown.
FIG. 16 is a schematic configuration diagram showing the configuration of the encoder 8 according to the third modification.
Here, FIG. 16A shows a front view of the encoder 8 viewed from the rotation axis direction (Z-axis direction) of the rotor 6, and FIG. 16B shows a cross section of the encoder 8 along the line AA ′. The figure is shown.

  In FIG. 16, an encoder 8 includes a rotor 6 having a light-dark lattice pattern 81 of 10 periods (m = 10), a light source unit 82, nine (n = 9) light receiving elements 11a to 19a, and the light receiving elements. 11a to 19a and a substrate 7 on which other control components are mounted. Here, when an arbitrary light receiving element among the light receiving elements 11a to 19a or a light receiving element included in the encoder 1 is simply indicated, it will be referred to as a light receiving element 10a (detection element) and will be described below. Moreover, the structure part which shows the whole light receiving elements 11a-19a respond | corresponds to the optical sensor part 20b (sensor part).

The light receiving elements 11a to 19a are equally arranged with respect to the displacement range (one rotation) of the rotor 6 in which 10 cycles (m = 10) are obtained.
The encoder 8 is a transmissive encoder, and as shown in FIG. 16B, the light sensor unit 20b (light receiving element 10a) emits the light emitted from the light source unit 82 via the light / dark lattice pattern 81. Receive light.

FIG. 17 is a block diagram showing a configuration of the encoder 8 in this modification.
In FIG. 17, the encoder 8 includes an optical sensor unit 20b, a switch unit 2, an A / D conversion unit 3, and a signal processing unit 4d. Here, the optical sensor unit 20b includes nine light receiving elements 11a to 19a. In this modification, a light source unit 82 and an optical sensor unit 20b are provided instead of the magnetic sensor unit 20, and the configuration of the signal processing unit 4d is different from that of the encoder 1 in the first embodiment except for the first. This is the same as the embodiment. In this figure, the same components as those in FIG. 2 are denoted by the same reference numerals, and the description thereof is omitted.

  The light source unit 82 is, for example, a light emitting element such as a laser diode that emits laser light, and irradiates the light / dark lattice pattern 81 with irradiation light (laser light) based on a drive signal supplied from a driver unit 44 described later. .

The signal processing unit 4 d includes a switching control unit 41, a position detection unit 42, and a driver unit 44.
The driver unit 44 generates a drive signal (for example, drive current) that drives light emission of the light source unit 82, and supplies the generated drive signal to the light source unit 82.

FIG. 18 is a diagram illustrating an output waveform of the optical sensor unit 20b in the present modification.
In FIG. 18, a waveform W11 indicates an output waveform of one light receiving element 10a (for example, the light receiving element 11a) when the rotor 6 is rotated once, for example. As shown in the waveform W11, each light receiving element 10a outputs a periodic signal of m periods (m = 10) equal to the number of light and dark of the light and dark lattice pattern by one rotation of the rotor 6.

  Outputs PD1 to PD9 indicate output signals corresponding to the light receiving elements 11a to 19a when the rotor 6 is stationary. In this case, in the signal generation unit 30, the switch unit 2 switches the nine output signals in a predetermined order and sequentially outputs them, and based on the sequential output signal output from the switch unit 2, the a cycle as shown in the waveform W12 A processing signal (fundamental wave signal) of (a = 1) is generated. Here, the processing signal indicated by the waveform W12 is a signal in which the electrical angle is displaced by 360 ° (changed by one cycle) with respect to the mechanical angle of 36 ° (= 360 ° / 10). Subsequent processing is the same as in the first embodiment.

  As described above, the basic operation of the encoder 8 is the same as that of the first embodiment except that the light receiving element 10a (optical sensor unit 20b) is used instead of the hall element 10 (magnetic sensor unit 20). Same as 1. Therefore, the encoder 8 has the same effect as the encoder 1 described above.

Next, another example of the optical encoder will be described as a fourth modification.
<Fourth Modification>
In the fourth modification, an example in which the encoder 8 of the third modification described above includes a slit 83 is shown.

FIG. 19 is a schematic configuration diagram showing a configuration of an encoder 8a according to a fourth modification.
Here, FIG. 19A shows a front view of the encoder 8a viewed from the rotation axis direction (Z-axis direction) of the rotor 6, and FIG. 19B shows a cross section of the encoder 8a along the line AA ′. The figure is shown. 19, the same components as those in FIG. 16 are denoted by the same reference numerals, and the description thereof is omitted.

In FIG. 19, the encoder 8a includes a light sensor portion 20b having nine light receiving elements 11a to 19a formed of a donut-shaped sensor array, and includes a slit 83 for adjusting the amount of light received by the light receiving element 10a. ing. The nine light receiving elements 11a to 19a are formed by dividing one rotation of the donut-shaped sensor array into equal areas. Further, one transmission pattern of the slit 83 is formed for each light receiving element 10a, and is equally arranged with respect to one turn of the rotor 6 like the light receiving element 10a.
Moreover, the slit 83 is arrange | positioned between the light-and-dark lattice pattern 81 and the optical sensor part 20b, as shown in FIG.19 (b).
With this configuration, the encoder 8a can detect position information similar to that of the encoder 8 of the third modification described above. Therefore, the encoder 8a has the same effect as the encoder 1 described above.

Next, another example of the optical encoder will be described as a fifth modification.
<Fifth Modification>
In the fifth modification example, in the optical encoder, as in the second modification example described above, the displacement range of the rotor 6 in which m cycles can be obtained is the total displacement range of the rotor 6 (for example, one rotation). An example in the case of a partial range will be described. That is, in the fourth modification, an example in which the arrangement range of the optical sensor unit 20b is not the entire circumference will be described.

FIG. 20 is a schematic configuration diagram showing a configuration of an encoder 8b according to a fifth modification.
Here, FIG. 20A shows a front view of the encoder 8b viewed from the rotation axis direction (Z-axis direction) of the rotor 6, and FIG. 20B shows a cross section of the encoder 8b along the line AA ′. The figure is shown. 20, the same components as those in FIG. 16 are denoted by the same reference numerals, and the description thereof is omitted.

In FIG. 20, an encoder 8b includes a rotor 6 having a 72-period light / dark lattice pattern 81a on the entire circumference, a light source 82, eight (n = 8) light receiving elements 11a to 18a, and the light receiving elements 11a to 11a. 18a and a substrate 7 on which other control components are mounted. Moreover, the structure part which shows the whole light receiving elements 11a-18a respond | corresponds to the optical sensor part 20b (sensor part).
Here, the eight (n = 9) light receiving elements 11a to 18a are equally arranged in the range of nine periods of brightness and darkness (range of 45 ° mechanical angle) of the light and dark lattice pattern 81a. In this case, the periodic signal of m period is a periodic signal of 9 periods, and the processed signal of a period is a processed signal of 1 period (| a | = (9-1 × 8) = 1).

FIG. 21 is a diagram illustrating an output waveform of the optical sensor unit 20b in the fifth modification.
In FIG. 21, a waveform W13 indicates an output waveform of one light receiving element 10a (for example, the light receiving element 11a) when the rotor 6 is rotated by 45 °, for example. As shown in the waveform W13, each light receiving element 10a outputs a periodic signal of m periods (m = 9) equal to the light / dark number in the 45 ° range of the light / dark lattice pattern 81a by the rotation of the rotor 6 by 45 °.

  Outputs PD1 to PD8 indicate output signals corresponding to the light receiving elements 11a to 18a when the rotor 6 is stationary. In this case, in the signal generation unit 30, the switch unit 2 switches the eight output signals in a predetermined order and sequentially outputs them, and based on the sequential output signal output from the switch unit 2, the a cycle as shown in the waveform W14 A processing signal (fundamental wave signal) of (a = 1) is generated. Here, the processing signal indicated by the waveform W14 is a signal in which the electrical angle is displaced by 360 ° (changed by one cycle) with respect to the mechanical angle of 5 ° (= 360 ° / 72). Subsequent processing is the same as in the first embodiment.

  Thus, even in the optical encoder, the displacement range of the rotor 6 in which m cycles can be obtained is not limited to the total displacement range (eg, one rotation) of the rotor 6, May be part of the range (eg 45 °).

Next, another example of the optical encoder will be described as a sixth modification.
<Sixth Modification>
In the sixth modification, an example in which the encoder 8b of the fifth modification described above includes a slit 83 is shown.

FIG. 22 is a schematic configuration diagram showing a configuration of an encoder 8c according to a sixth modification.
Here, FIG. 22A shows a front view of the encoder 8c viewed from the rotation axis direction (Z-axis direction) of the rotor 6, and FIG. 22B shows a cross section of the encoder 8c along the line AA ′. The figure is shown. 22, the same components as those in FIG. 20 are denoted by the same reference numerals, and the description thereof is omitted.

In FIG. 22, the encoder 8 c includes an optical sensor unit 20 b having eight light receiving elements 11 a to 18 a formed by a fan-shaped sensor array, and includes a fan-shaped slit 83 that adjusts the amount of light received by the light receiving element 10 a. I have.
Further, as shown in FIG. 22B, the slit 83 is disposed between the light / dark lattice pattern 81a and the optical sensor unit 20b.
With this configuration, the encoder 8c can detect position information similar to that of the encoder 8b of the fifth modification described above. Therefore, the encoder 8c has the same effect as the encoder 1 described above.

FIG. 23 is a schematic configuration diagram illustrating another configuration example of the encoder 8c according to the sixth modification.
FIG. 23A shows an example in which the encoder 8c includes a lens 84, and the light source unit 82 irradiates the light-dark lattice pattern 81a with parallel light via the lens 84.
FIG. 23B shows an example in which a reflective bright / dark grating pattern 81b is applied to the encoder 8c. In this case, the encoder 8c shows an example when applied to a reflective optical encoder.
FIG. 23C shows an example in which a reflection type light / dark grating pattern 81b is applied to the encoder 8c and a lens 84 is further provided.

As with the encoder 8, the encoder 8 (8a, 8b) can be provided with a lens 84 and a reflection light / dark grating pattern 81b can be applied.
As described above, the encoder 8 (8a to 8c) may be configured to include the lens 84, or may be configured to apply the reflective light-dark lattice pattern 81b.

In the above embodiments, the encoder 1 (1a to 1f) is a rotary encoder. However, the present invention is not limited to this. For example, a linear encoder (linear encoder) may be used. .
Next, as a seventh modification, a modification when applied to a linear encoder will be described.

<Seventh Modification>
FIG. 24 is a schematic configuration diagram showing the configuration of the encoder 9 (9a) according to this modification.
FIG. 24A shows an example in which the encoder 1 according to the first embodiment is applied to a linear encoder 9 (linear encoder).
The encoder 9 includes a scale 6 a (linear scale) instead of the rotor 6 (disk 61) and a magnet 5 c that is a linear multipolar magnet instead of the magnet 5. In FIG. 24A, eight (n = 8) Hall elements 11 to 18 are equally arranged in the displacement range L1 of the scale 6a in which seven periods (m = 7) of the periodic signal are obtained. In this case, the periodic signal of m period is a periodic signal of 7 periods, and the processed signal of a period is a processed signal of 1 period (| a | = (7-1 × 8) = | −1 |). .
The basic operation of the encoder 9 is the same as that of the encoder 1 except that a scale 6a (linear scale) is used instead of the rotor 6 (disk 61). Therefore, the encoder 9 has the same effect as the encoder 1 described above.

FIG. 24B shows an example in which the encoder 1 according to the first embodiment is applied to an optical and linear encoder 9a (linear encoder).
The encoder 9 a includes a scale 6 a (linear scale) instead of the rotor 6 (disk 61) and a light / dark lattice pattern 81 b instead of the magnet 5. The encoder 9a includes a light receiving element 10a (optical sensor unit 20b) instead of the hall element 10 (magnetic sensor unit 20). The scale 6a is irradiated with parallel light from the Z-axis direction.
In FIG. 24B, eight (n = 8) light receiving elements 11a to 18a are equally arranged in the displacement range of the scale 6a in which seven periods (m = 7) of the periodic signal are obtained. In this case, the periodic signal of m period is a periodic signal of 7 periods, and the processed signal of a period is a processed signal of 1 period (| a | = (7-1 × 8) = | −1 |). .

  The encoder 9a uses a scale 6a (linear scale) instead of the rotor 6 (disk 61), and light receiving elements 11a to 18a (optical sensor part 20b) instead of the hall element 10 (magnetic sensor part 20). Except for, the basic operation is the same as that of the encoder 1. Therefore, the encoder 9a has the same effect as the encoder 1 described above.

Further, in each of the above embodiments, the n detection elements (Hall elements 10) have been described as being uniformly arranged in the displacement range of the rotor 6 where m cycles can be obtained. There may be no form, and a form in which the rotor 6 is arranged within a predetermined range (partial range) of the displacement range of the rotor 6 from which m cycles can be obtained may be used.
Next, in the eighth modification to the tenth modification, n detection elements are arranged within a predetermined range (partial range) of the displacement range of the rotor 6 in which m cycles can be obtained. A modification example in the case of the above will be described.

<Eighth Modification>
The eighth modification example shows an example in which the light receiving element 10a is arranged in a part of the displacement range of the rotor 6 in which m cycles can be obtained in the third modification example.
FIG. 25 is a schematic configuration diagram showing a configuration of an encoder 8d according to an eighth modification.
Here, FIG. 25A shows a front view of the encoder 8d viewed from the rotation axis direction (Z-axis direction) of the rotor 6, and FIG. 25B shows a cross section of the encoder 8d along the line AA ′. The figure is shown. As shown in FIG. 25B, the encoder 8d is a reflective optical encoder, and includes a reflective light / dark lattice pattern 81c having a light / dark pattern similar to that of the third modification.

  As shown in FIG. 25A, in this modification, the four light receiving elements 10a arranged at the positions of the broken lines in the third modification are arranged at positions rotated by 180 °. Thereby, the light receiving elements 11a to 19a are arranged in a partial range of the displacement range (one rotation) of the rotor 6 in which 10 cycles are obtained. The nine light receiving elements 11a to 19a are arranged so as to obtain nine output signals having different phases obtained by equally dividing the period a (here, one period) of the processing signal.

FIG. 26 is a diagram illustrating an output waveform of the optical sensor unit 20b in the present modification.
In FIG. 26, a waveform W15 indicates an output waveform of one light receiving element 10a (for example, the light receiving element 11a) when the rotor 6 is rotated once, for example. Outputs PD1 to PD9 indicate output signals corresponding to the light receiving elements 11a to 19a when the rotor 6 is stationary. A waveform W16 indicates a case where the light receiving elements 11a to 19a are switched in the order of arrangement and output.
In the present modification, the signal generation unit 30 changes the order of switching the switch unit 2 to every other one of the arrangement order as shown in FIG. 26, thereby a cycle (a = 1) as shown in the waveform W17. The processing signal (fundamental wave signal) is generated.

<Ninth Modification>
The ninth modification shows another example in the case where the light receiving element 10a is arranged in a part of the displacement range of the rotor 6 in which m cycles can be obtained in the third modification.
FIG. 27 is a schematic configuration diagram showing a configuration of an encoder 8e according to a ninth modification.

Here, FIG. 27A shows a front view of the encoder 8e viewed from the rotation axis direction (Z-axis direction) of the rotor 6. FIG.
As shown in FIG. 27A, in this modification, the three light receiving elements 10a arranged at the position of the lower right broken line in the third modification are arranged at positions rotated by −108 °, In the third modification, the three light receiving elements 10a arranged at the position of the lower left broken line are arranged at a position rotated by 108 °. Thereby, the light receiving elements 11a to 19a are arranged in a partial range of the displacement range (one rotation) of the rotor 6 in which 10 cycles are obtained. The nine light receiving elements 11a to 19a are arranged so as to obtain nine output signals having different phases obtained by equally dividing the period a (here, one period) of the processing signal.

FIG. 27B is a diagram showing an output waveform of the optical sensor unit 20b in this modification.
In FIG. 27B, a waveform W18 indicates an output waveform of one light receiving element 10a (for example, the light receiving element 11a) when the rotor 6 is rotated once, for example. Outputs PD1 to PD9 indicate output signals corresponding to the light receiving elements 11a to 19a when the rotor 6 is stationary. A waveform W19 indicates a case where the light receiving elements 11a to 19a are switched in the order of arrangement and output.
In this modification, the signal generation unit 30 changes the order of switching the switch unit 2 as illustrated in FIG. 27B, thereby processing a signal (a = 1) as illustrated in the waveform W20 (a = 1). Fundamental wave signal).

  The eighth and ninth modifications are cases where the m cycle is 10 cycles. Therefore, the lattice pitch of the light / dark lattice pattern 81c is 36 ° (= 360/10). As described above, when the light receiving element 10a is rotated and arranged, it is rotated by an integral multiple of the grating pitch (36 °). Thereby, even if the position of the light receiving element 10a is changed, the electrical angle obtained by the light receiving element 10a is not changed.

<Tenth Modification>
The tenth modification shows an example in which the same arrangement as that of the eighth and modification examples is applied to a magnetic linear encoder.
FIG. 28 is a schematic configuration diagram showing a configuration of an encoder 9b according to the tenth modification.
As shown in FIG. 28, the encoder 9b shifts four broken lines (Hall elements 12, 14, 16, and 17) when the Hall elements 10 are arranged uniformly within the displacement range L1 of the scale 6a by a distance L3. It is arranged. Here, the distance L3 is a distance that is three times the pitch of the magnetic pole pattern. In this case, the signal generation unit 30 generates a processing signal (fundamental wave signal) having a period (a = 1) by changing the order of switching the switch unit 2 to every other switching order.
In this way, by arranging the eight Hall elements 11 to 18 as shown in FIG. 28, it is possible to obtain a processing signal similar to that of the encoder 9 of FIG.

  When the eighth modification to the tenth modification are applied, the light receiving elements 10a (Hall elements 10) can be arranged in a narrower range than the case where the light receiving elements 10a (Hall elements 10) are arranged uniformly in a displacement range in which m cycles can be obtained. . Therefore, it is possible to reduce the size of the optical sensor unit 20b (magnetic sensor unit 20).

In addition, although each said modification demonstrated the case where it applied with respect to 1st Embodiment, it is not limited to this, You may apply with respect to said each embodiment.
Moreover, although each said embodiment demonstrated the form used independently, the form used combining said each embodiment may be sufficient.

  In the second embodiment, the position detection unit 42a has been described as having the filter unit 423. However, the synchronous detection is directly performed on the fundamental signal (reference signal) without the filter unit 423. Thus, the phase may be obtained, or the phase information may be detected using another method.

  Further, in the third embodiment, the correction unit 43 has been described as correcting in the inverse Fourier transform method, but it is also possible to perform correction in the phase modulation method as in the second embodiment. For example, by generating the output SHn corrected by any one of the following formula (19), formula (20), and formula (21) for the output (fn (θ)) of each Hall element 10 When the positional deviation of the Hall element 10 occurs, the correction process can be performed.

Here, the phase value (θ ^) is a phase value detected by the position detection unit 42a as the previous (latest) position information.
The correction unit 43 may select one of the above formulas (19) to (21) according to the phase difference δ and the required accuracy, and execute the correction process. The correction process may be executed for only one predetermined method among the equations (19) to (21).

  Moreover, in said 1st and 3rd-5th embodiment, the signal production | generation part 30 (30a) may include the production | generation process of a Fourier coefficient, and the form which outputs a Fourier coefficient as a process signal of a period may be sufficient. Moreover, in said 2nd Embodiment, the signal generation part 30 may include the process by a filter, and the form which outputs the output signal of a filter as a processed signal of a period may be sufficient.

In the fourth embodiment, the gain adjustment unit 50 is provided between each Hall element 10 and the switch unit 2. However, the present invention is not limited to this. For example, the gain adjustment unit 50 may be provided between the switch unit 2 and the A / D conversion unit 3, or the signal level may be adjusted after digitization by the A / D conversion unit 3. When the signal level of each Hall element 10 is adjusted in the output signal after the switch unit 2, it can be processed serially, so that the configuration of the gain adjusting unit 50 can be reduced.
In addition, as an example of the adjustment unit that adjusts the signal level, the form using the gain adjustment type amplifier has been described. Good.

Further, in each of the above embodiments, the switching control unit 41 has been described as an example in which the output signal of the Hall element 10 is switched in the clockwise order, for example, but is not limited thereto. For example, the switching control unit 41 may switch the output signal of the Hall element 10 in a predetermined order that is not easily affected by rotation.
In each of the above embodiments, the A / D conversion unit 3 (3A, 3B) has been described as being provided at the subsequent stage of the switch unit 2 (2A, 2B). In another embodiment, each Hall element 10 may include an individual A / D conversion unit 3.

  Further, in the sixth embodiment, as an example of the driving device DR, the case of the motor device that includes the rotary encoder 1 (1a to 1d) and rotates the rotor 6 has been described, but the present invention is not limited thereto. is not. For example, the driving device DR may be a stage device that includes the above-described linear encoder 9 (9a) and drives a stage to which the scale 6a is connected. For example, a machine tool, a precision machine, and a semiconductor chip It may be a mounter, a stepper device, or the like.

  In each of the above-described embodiments, each unit of the signal processing unit 4 (4a to 4c) may be realized by dedicated hardware, and includes a memory and a CPU, and is realized by a program. Also good.

  The above-described encoder 1 (1a to 1f) has a computer system therein. The processing steps of the encoder 1 (1a to 1f) described above are stored in a computer-readable recording medium in the form of a program, and the above processing is performed by the computer reading and executing this program. Here, the computer-readable recording medium means a magnetic disk, a magneto-optical disk, a CD-ROM, a DVD-ROM, a semiconductor memory, or the like. Alternatively, the computer program may be distributed to the computer via a communication line, and the computer that has received the distribution may execute the program.

  1, 1a, 1b, 1c, 1d, 1e, 1f, 8, 8a, 8b, 8c, 8d, 8e, 9, 9a, 9b ... encoder, 6 ... rotor, 6a ... scale, 10, 11, 12, 13 , 14, 15, 16, 17, 18, 19, 111, 112, 112, 113, 114, 115, 116, 117, 118, 121, 122, 122, 123, 124, 125, 126, 127, 128, 129 ... Hall element, 10a, 11a, 12a, 13a, 14a, 15a, 16a, 17a, 18a, 19a ... Light receiving element, 21, 22 ... Sensor group, 30, 30a ... Signal generator, 42, 42a, 42b, 42c ... position detection unit, 43 ... correction unit, 50 ... gain adjustment unit, DR ... drive device, MTR ... motor

Claims (15)

N detection elements that output a periodic signal according to position information of the driven body, and in a displacement range of the driven body in which m periods (where m is an integer of 2 or more) of the periodic signal are obtained. n detection elements arranged so as to obtain n output signals having different phases obtained by dividing a period (where | a | = (m−k × n), k is an integer of 1 or more); ,
A signal generator that generates the processing signal of the period a based on the n output signals output by the n detection elements;
An encoder comprising: a detection unit configured to detect position information of the driven body based on the processing signal of the period a generated by the signal generation unit. The encoder according to claim 1, wherein the m period is larger than half of the n. The n detection elements are:
The encoder according to claim 1 or 2, wherein the encoder is equally arranged in a displacement range of the driven body in which the m period is obtained. The n detection elements are:
4. The arrangement according to claim 1, wherein the n output signals having the same phase difference are obtained in a displacement range of the driven body in which the m period is obtained. 5. An encoder according to claim 1. The n detection elements are:
The encoder according to any one of claims 1 to 3, wherein the encoder is disposed within a predetermined range of a displacement range of the driven body from which the m period is obtained. The encoder according to claim 1, wherein the m period is equal to the number of cycles of the periodic signal in a displacement range of the driven body. The detector is
The encoder according to any one of claims 1 to 6, wherein the position information is detected as a phase shift between the processing signal of the period a and a reference signal of the processing signal. The detector is
The Fourier coefficient of the order corresponding to the a cycle is generated based on the processing signal of the a cycle, and the position information of the driven body is detected based on the generated Fourier coefficient. The encoder according to claim 6. The signal generator is
A switching unit that sequentially switches and outputs the n output signals in a predetermined order, and generates the processing signal of the period a based on the sequential output signal output from the switching unit. The encoder according to any one of claims 1 to 8. The phase difference between the N phase signals and the n output signals, and the n output signals, with N phase signals (where N = n) obtained by equally dividing the period a as reference signals. And a correction unit that corrects the n output signals so that the n output signals become the N phase signals, and generates corrected output information.
The detector is
The encoder according to any one of claims 1 to 9, wherein position information of the driven body is detected based on the corrected output information generated by the correction unit. The encoder according to any one of claims 1 to 10, further comprising an adjustment unit that adjusts a signal level of the n output signals output from the n detection elements. A first pattern in which a periodic signal of m1 period is obtained as the periodic signal of m period in a predetermined displacement range of the driven body, and a periodic signal of m2 period different from the m1 period are used as the periodic signal of m period. A sign plate having a second pattern obtained;
N1 detection elements arranged so that n1 output signals having different phases obtained by equally dividing the a1 period as the a period in the predetermined displacement range are obtained based on the first pattern. A first detection element group having n as the n detection elements;
In the predetermined displacement range, n2 detection elements are arranged so that n2 output signals having different phases obtained by equally dividing the a2 period as the a period are obtained based on the second pattern. A second detection element group having n as the n detection elements;
With
The signal generator is
Based on the n1 output signals output from the first detection element group, the processing signal of the a1 period is generated, and based on the n2 output signals output from the second detection element group, a2 period processing signal is generated,
The detector is
The position information indicating the absolute position of the driven body is detected based on the a1 period processing signal and the a2 period processing signal generated by the signal generation unit. The encoder according to any one of 11. The encoder according to any one of claims 1 to 12, wherein the signal generation unit generates the processing signal of the a cycle using aliasing based on the m cycles and the n. The signal generation unit generates the processing signal of the a cycle from the m output signals of the m cycles of the periodic signal by using aliasing. The encoder according to item. The encoder according to any one of claims 1 to 14,
A drive unit for driving the driven body;
A drive device comprising:

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