JP2013124909A - Encoder and driver - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce erroneous detection of the position of a driven object.SOLUTION: An encoder comprises a code disc having a pattern indicating positional information of a driven object, a plurality of detection element for detecting the pattern of the code disc, a converter which converts a detection signal detected by each of the plurality of detection elements into a binary signal, an adjustment control section which allows the converter to adjust the detection signal for each detection element on the basis of adjustment information determined for each detection element, and a position detection section which detects a position of the driven object.

Description

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

  In recent years, an encoder that detects the position of a driven body such as a rotor having a pattern based on a detection signal obtained by detecting a pattern indicating position information by a detection unit is known (for example, see Patent Document 1). reference). In such an encoder, the detection unit includes a plurality of detection elements, and detects the position of the driven body based on a detection signal obtained by shaping the detection signal detected by the plurality of detection elements.

JP-A-5-203463

However, for example, in the encoder as described above, when the detection unit includes a light source and a light receiving element is used as the detection element, the distance of the optical path from the light source to the plurality of light receiving elements through the pattern varies depending on each light receiving element. Sometimes. In such a case, the output values of detection signals detected by a plurality of light receiving elements may vary depending on each light receiving element. For this reason, the encoder as described above may erroneously detect the position of the driven body when a disturbance such as noise occurs, for example.
Thus, the encoder as described above has a problem that the position of the driven body may be erroneously detected.

  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 device that can reduce erroneous detection of the position of a driven body.

  In order to solve the above problem, an embodiment of the present invention includes a code plate having a pattern indicating position information of a driven body, a plurality of detection elements for detecting the pattern of the code plate, and the plurality of detections. A conversion unit that converts a detection signal detected by each element into a binary signal, and an adjustment control that causes the conversion unit to adjust the detection signal for each detection element based on adjustment information determined for each detection element And a position detector that detects the position of the driven body based on the binarized signal.

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

  According to the present invention, erroneous detection of the position of the driven body can be reduced.

It is a block diagram which shows the encoder by 1st Embodiment. It is a figure which shows the switching operation | movement of the detection signal of the light receiving element in this embodiment. It is a figure which shows adjustment operation | movement of the detection signal of the encoder in 1st Embodiment. It is a block diagram which shows the encoder by 2nd Embodiment. It is a figure which shows adjustment operation | movement of the detection signal of the encoder by 2nd Embodiment. It is a block diagram which shows the encoder by 3rd Embodiment. It is a figure which shows adjustment operation | movement of the detection signal of the encoder in 3rd Embodiment. It is a block diagram which shows the encoder by 4th Embodiment. It is a block diagram which shows the encoder by 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.

Hereinafter, an encoder according to an embodiment of the present invention will be described with reference to the drawings.
[First Embodiment]
FIG. 1 is a block diagram showing an encoder 100 according to the present embodiment.
In FIG. 1, an encoder 100 includes a code plate 2, a light receiving unit 3, a switching unit 4, a signal converting unit 5, a signal processing unit 6, a light source 10, a driver unit 11, an amplifier (12, 13), and a nonvolatile storage unit 14. It has. In the embodiment, as an example, an example in which the encoder 100 is a transmissive optical absolute encoder will be described.

The code plate 2 is, for example, a rotary code plate mounted on a rotor (driven body) or the like, and has a pattern indicating position information of the rotor. For example, the code plate 2 is provided with an incremental pattern 22 used for interpolation processing and an absolute pattern 21 indicating position information as an absolute position in order from the outer peripheral side in a disc shape. In this embodiment, as an example, a rotary type encoder in which the code plate 2 rotates will be described.
Here, the position information is information indicating a movement angle (eg, rotation angle), a movement position (eg, rotation position), and the like. The absolute position is, for example, the absolute angular position or the absolute movement position (eg, absolute rotation position) of the rotor.

  For example, the absolute pattern 21 and the incremental pattern 22 form a pattern indicating position information by a transmissive pattern region that transmits light and a non-transmissive pattern region that does not transmit light. The absolute pattern 21 and the incremental pattern 22 are disposed between the light source 10 and the light receiving unit 3 so that the light receiving unit 3 can receive light irradiated through the transmission pattern region from the light source 10. The absolute pattern 21 and the incremental pattern 22 transmit light emitted from the light source 10 according to the transmission pattern region, and cause the light receiving unit 3 to receive the transmitted light.

The light receiving unit 3 (detecting unit) is disposed to face the code plate 2 and receives light emitted from the light source 10 via the absolute pattern 21 and the incremental pattern 22, thereby causing the absolute pattern 21 and the incremental pattern 22 to be received. To detect.
The light receiving unit 3 includes an absolute light receiving unit 30 and an incremental light receiving unit 37.

  The incremental light receiving unit 37 is disposed so as to face the incremental pattern 22 provided on the code plate 2. The incremental light receiving unit 37 receives light emitted from the light source 10 via the incremental pattern 22 and detects the incremental pattern 22 based on the received light quantity. The incremental light receiving unit 37 outputs two detection signals corresponding to the detected incremental pattern 22, and outputs an A phase detection signal and a B phase detection signal that are 90 degrees out of phase with each other. The incremental light receiving unit 37 outputs the A phase detection signal to the amplifier 12 and the B phase detection signal to the amplifier 13, respectively.

The absolute light receiving unit 30 is arranged to face the absolute pattern 21 provided on the code plate 2, receives light emitted from the light source 10 through the absolute pattern 21, and based on the received light quantity, the absolute pattern 21. Is detected. The absolute light receiving unit 30 includes, for example, a plurality of (for example, six) light receiving elements 31 to 36 having a minimum reading pitch corresponding to the absolute pattern 21. The absolute light receiving unit 30 outputs each detection signal detected by a plurality of (for example, six) light receiving elements 31 to 36 to the switching unit 4.
Each of the light receiving elements 31 to 36 (detection elements) is, for example, a photodiode, a phototransistor, or the like, and forms the absolute light receiving unit 30 in a form adjacent to each other in an arrangement corresponding to the absolute pattern 21.

The distance of the optical path from the light source 10 to the light receiving elements 31 to 36 through the absolute pattern 21 varies depending on the arrangement of the light receiving elements 31 to 36. Therefore, the detection signals output from the light receiving elements 31 to 36 may have nonuniform signal levels. That is, since the distance of the optical path of the light receiving elements (31, 36) located at both ends of the absolute light receiving unit 30 is longer than the distance of the optical path of the light receiving elements (33, 34) disposed in the center, the light receiving elements (31, 36) The signal level of the output signal 36) is lower than the signal level of the output signal of the light receiving element (33, 34).
In order to reduce the nonuniformity of the signal level in the plurality of light receiving elements (31 to 36), the encoder 100 in the present embodiment performs control for adjusting the detection signal. The control for adjusting the detection signal will be described later in detail.

  The switching unit 4 is disposed between the absolute light receiving unit 30 and the signal converting unit 5, and any one of the six light receiving elements 31 to 36 is selected based on a switching signal supplied from the signal processing unit 6. Switches whether to output a detection signal (ABS phase detection signal). That is, the switching unit 4 sequentially switches one of the six light receiving elements 31 to 36 according to the switching signal supplied from the signal processing unit 6 and outputs an ABS phase detection signal. The switching unit 4 includes a switch unit 41 including a plurality of (for example, six) switches and a switch control unit 42.

  The switch unit 41 includes, for example, six switches corresponding to the light receiving elements 31 to 36, respectively. Based on the control signal supplied from the switch control unit 42, the six switches convert one of the six detection signals, which are detection signals corresponding to the light receiving element 36, from the detection signal corresponding to the light receiving element 31 to the ABS. Selectively output as phase detection signal.

  The switch control unit 42 switches one of the six detection signals described above according to the switching signal supplied from the signal processing unit 6, and supplies the control signal to be output as the ABS phase detection signal to the switch unit 41. To do. For example, the switch control unit 42 switches the output of the absolute light receiving unit 30 one signal at a time in order and outputs the signal from the switch unit 41.

The signal conversion unit 5 amplifies the ABS phase detection signal output from the switching unit 4 and converts it into a binary signal. That is, the signal converter 5 converts the detection signals detected by the six light receiving elements 31 to 36 described above into binary signals. Here, binarization means that a detection signal, which is an analog signal, is converted into a first signal level (for example, L (low) level) and a second signal level (for example, based on a predetermined threshold voltage (threshold level)). For example, conversion to a signal (digital signal) having two signal levels (H (high) level). Note that the first signal level and the second signal level correspond to logic states in the digital signal. Here, for example, it is assumed that the L level corresponds to the logical state “0” and the H level corresponds to the logical state “1”.
The signal conversion unit 5 supplies a binary signal obtained by converting the ABS phase detection signal to the signal processing unit 6. The signal conversion unit 5 includes an amplifier 51 and a binarization unit 52.

The amplifier 51 (amplifying unit) amplifies the ABS phase detection signal and outputs the amplified signal (ABS phase detection signal) to the binarization unit 52. The amplifier 51 is, for example, a gain adjustment type amplification circuit, and changes the gain (gain) of signal amplification based on the gain adjustment signal supplied from the signal processing unit 6.
The binarization unit 52 is, for example, a comparator (comparator), and converts the ABS phase detection signal amplified by the amplifier 51 into a binarized signal based on a predetermined threshold voltage. For example, when the signal level of the amplified ABS phase detection signal is equal to or higher than a predetermined threshold voltage, the binarization unit 52 outputs an H level as a binarization signal. For example, when the signal level of the amplified ABS phase detection signal is less than a predetermined threshold voltage, the binarization unit 52 outputs an L level as a binarized signal. The binarization unit 52 supplies the converted binarized signal to the signal processing unit 6.

The amplifier 12 is, for example, an amplifier circuit, amplifies the A phase detection signal output from the incremental light receiving unit 37, and supplies the amplified A phase detection signal to the signal processing unit 6.
The amplifier 13 is, for example, an amplifier circuit, amplifies the B phase detection signal output from the incremental light receiving unit 37, and supplies the amplified B phase detection signal to the signal processing unit 6.

The driver unit 11 generates a drive signal for driving the light source 10 based on the control signal supplied from the signal processing unit 6, and supplies the generated drive signal to the light source 10.
The light source 10 is a light emitting element such as an LED (light emitting diode), for example, and irradiates light to the absolute pattern 21 and the incremental pattern 22 of the code plate 2 based on a drive signal supplied from the driver unit 11.

  The non-volatile storage unit 14 (storage unit) is a storage unit such as an EEPROM (Electrically Erasable Programmable Read-Only Memory) or a flash memory, and stores adjustment information described later. The nonvolatile storage unit 14 stores adjustment information determined for each light receiving element (31 to 36). In the present embodiment, the nonvolatile storage unit 14 stores adjustment information supplied from a setting device 200 (adjustment information setting unit 210) described later.

  The signal processing unit 6 controls each unit in the encoder 100 and performs signal processing. For example, the signal processing unit 6 generates a control signal that causes the light source 10 to output a drive signal, and supplies the generated control signal to the driver unit 11. Further, the signal processing unit 6 performs signal processing for calculating (detecting) position information (for example, the position of the rotating body) based on, for example, the A phase detection signal, the B phase detection signal, and the binarized signal. The calculated rotational position is output to the outside of the encoder 100. Here, the A phase detection signal and the B phase detection signal are supplied from the incremental light receiving unit 37 via the amplifiers (12, 13), and the binarized signal is supplied from the absolute light receiving unit 30 to the switching unit 4 and the signal converting unit 5. This corresponds to the ABS phase detection signal supplied via.

In addition, the signal processing unit 6 performs adjustment control for causing the signal conversion unit 5 to adjust the detection signal for each light receiving element (31 to 36) based on adjustment information determined for each light receiving element (31 to 36), for example. Do. Details of this adjustment control will be described later.
The signal processing unit 6 includes an adjustment control unit 60, a D / A (digital / analog) unit 61, A / D (analog / digital) units (62, 63), and a position detection unit 7.

The A / D unit 62 is, for example, an analog / digital converter, which converts an A phase detection signal that is an analog signal supplied from the amplifier 12 into a digital signal, and converts the converted digital signal (A phase detection signal) to a position. It supplies to the detection part 7.
The A / D unit 63 is, for example, an analog / digital converter, which converts a B-phase detection signal that is an analog signal supplied from the amplifier 13 into a digital signal, and converts the converted digital signal (B-phase detection signal) to a position. It supplies to the detection part 7.

  Based on the A phase detection signal and the B phase detection signal supplied from the A / D unit (62, 63) and the binarized signal supplied from the signal conversion unit 5, the position detection unit 7 For example, the position of the rotating body) is detected. The position detection unit 7 outputs the detected position information to the outside of the encoder 100. The position detection unit 7 includes an absolute address processing unit 71, an interpolation processing unit 72, and a synthesis processing unit 73.

The absolute address processing unit 71 generates absolute position information in which the absolute pattern 21 is detected based on the binarized signal supplied from the signal conversion unit 5. The absolute address processing unit 71 outputs a switching signal to the switch control unit 42 of the switching unit 4. For example, the absolute address processing unit 71 supplies a switching signal to the switch control unit 42 to sequentially output the detection signals of the light receiving elements 31 to 36 as ABS phase detection signals, and the signal phase conversion unit 5 outputs the ABS phase detection signals. A binarized binarized signal is acquired. Since the binarized signal corresponds to a signal obtained by binarizing the detection signal corresponding to the pattern formed in the absolute pattern 21, the absolute address processing unit 71 acquires the binarized signal in order. Thus, 6-bit pattern data detected by the light receiving elements 31 to 36 is acquired. The absolute address processing unit 71 converts the acquired 6-bit pattern data into absolute position information corresponding to the absolute address of the code plate 2. The absolute address processing unit 71 supplies the converted (generated) absolute position information to the synthesis processing unit 73.
The absolute address processing unit 71 supplies the above switching signal to the adjustment control unit 60.

The interpolation processing unit 72 performs interpolation processing based on the A phase detection signal and the B phase detection signal supplied from the A / D unit (62, 63), and generates relative position information. The interpolation processing unit 72 supplies the generated relative position information to the synthesis processing unit 73.
The composition processing unit 73 performs composition processing on the absolute position information supplied from the absolute address processing unit 71 and the relative position information supplied from the interpolation processing unit 72, and combines the position information (for example, the rotating body). Position).

  Based on the adjustment information determined for each of the light receiving elements (31 to 36), the adjustment control unit 60 selectively transmits the detection signals of the light receiving elements 31 to 36 to the signal converting unit 5 for each of the light receiving elements (31 to 36). Let them adjust. For example, the adjustment control unit 60 converts the detection signal output from the switched light receiving element (31 to 36) based on the adjustment information corresponding to the light receiving element (31 to 36) switched by the switching unit 4. Adjust to part 5. In addition, for example, the adjustment control unit 60 outputs detection signals output from the switched light receiving elements (31 to 36) based on a plurality of pieces of adjustment information that are output one by one in response to switching by the switching unit 4. The conversion unit 5 is adjusted. For example, the plurality of pieces of adjustment information may be different signal information. Further, for example, when a plurality of pieces of adjustment information have predetermined output characteristics such as symmetry in the detection signals obtained from the respective light receiving elements (31 to 36), only a part (for example, at least two) of different signals It may be information.

  For example, the adjustment control unit 60 reads the adjustment information stored in the nonvolatile storage unit 14. Based on the read adjustment information, the adjustment control unit 60 causes the signal conversion unit 5 to adjust the detection signal so that the output characteristics of the six detection signals detected by the six light receiving elements 31 to 36 are matched. For example, the output characteristic includes the maximum signal level of the detection signal or the minimum signal level of the detection signal. In this case, the adjustment control unit 60 causes the signal conversion unit 5 to adjust the detection signal so that the maximum signal level or the minimum signal level in the six detection signals matches based on the read adjustment information.

  For example, the adjustment control unit 60 causes the D / A unit 61 to output a voltage corresponding to the adjustment information as a gain adjustment signal based on the adjustment information read from the nonvolatile storage unit 14. That is, the adjustment control unit 60 causes the signal conversion unit 5 to adjust the detection signal by outputting a gain adjustment signal via the D / A unit 61 and changing the gain (gain) of the amplifier 51.

The D / A unit 61 is, for example, a digital / analog converter, and converts the digital signal supplied from the adjustment control unit 60 into an analog signal having a voltage specified by the digital signal. The digital signal supplied from the adjustment control unit 60 is a signal indicating a voltage for changing the gain (gain) of the amplifier 51 determined based on the adjustment information corresponding to each detection signal of the six light receiving elements 31 to 36. It is. The D / A unit 61 supplies the converted analog signal to the amplifier 51 as a gain adjustment signal.
Here, the encoder 100 includes a signal adjustment unit 8 that adjusts detection signals of the light receiving elements 31 to 36 for each light receiving element (31 to 36) based on adjustment information determined for each light receiving element (31 to 36). I have. In FIG. 1, the signal adjustment unit 8 corresponds to a D / A unit 61 and an amplifier 51.

The encoder 100 is connected to the setting device 200 as shown in FIG. 1 when setting the adjustment information described above.
The setting device 200 is, for example, a setting jig that stores adjustment information in the nonvolatile storage unit 14 in a manufacturing process, or a calibration device (calibration device) that resets the adjustment information. The setting device 200 includes an adjustment information setting unit 210.

  For example, the adjustment information setting unit 210 is configured so that the binarized signals binarized based on the detection signals of the six light receiving elements 31 to 36 are each at the H level (logic state “1”). Change the position of. The adjustment information setting unit 210 measures the voltage level of the node N1 which is a signal line of the ABS phase detection signal and the voltage level of the node N2 which is the output signal line of the amplifier 51 for each light receiving element (31 to 36). Based on this, adjustment information for each light receiving element (31 to 36) is determined. In other words, the adjustment information setting unit 210 measures the voltage of the node N1 and the voltage of the node N2 for each light receiving element (31 to 36), and sets the adjustment information for each light receiving element (31 to 36) based on the measurement result. Generate. The adjustment information setting unit 210 stores the adjustment information generated for each light receiving element (31 to 36) in the nonvolatile storage unit 14. Furthermore, the adjustment information setting unit 210 may measure the voltage of the node N1 and the voltage of the node N2 for each light receiving element (31 to 36) to check whether the set adjustment information is set correctly.

Next, the operation of the encoder 100 in this embodiment will be described.
When the encoder 100 detects position information, the signal processing unit 6 supplies a control signal that causes the driver unit 11 to irradiate the light source 10 with light. The light source 10 irradiates the code plate 2 with light based on the drive signal supplied from the driver unit 11. The light receiving unit 3 receives light emitted from the light source 10 to the light receiving unit 3 through the absolute pattern 21 and the incremental pattern 22 of the code plate 2. The incremental light receiving unit 37 of the light receiving unit 3 supplies detection signals (A phase detection signal and B phase detection signal) obtained by detecting the incremental pattern 22 to the signal processing unit 6 via the amplifiers (12, 13).

On the other hand, the absolute light receiving unit 30 of the light receiving unit 3 outputs detection signals of the light receiving elements 31 to 36 to the switching unit 4.
FIG. 2 is a diagram illustrating a detection signal switching operation of the light receiving elements 31 to 36 in the present embodiment.
In this figure, a period T1 shows a state in which the switching unit 4 outputs the detection signal of the light receiving element 31 as an ABS phase detection signal in response to the switching signal. In this case, the switch control unit 42 supplies the switch unit 41 with a control signal for turning on the switch corresponding to the light receiving element 31 and turning off the switch corresponding to each of the light receiving elements 32 to 36. Based on the control signal supplied from the switch control unit 42, the switch unit 41 changes the state of each switch so as to output the detection signal of the light receiving element 31 as an ABS phase detection signal.

Moreover, the period T6 has shown the state in which the switching part 4 is outputting the detection signal of the light receiving element 36 as an ABS phase detection signal according to a switching signal. In this case, the switch control unit 42 supplies the switch unit 41 with a control signal for turning on the switch corresponding to the light receiving element 36 and turning off the switch corresponding to each of the light receiving elements 31 to 35. Based on the control signal supplied from the switch control unit 42, the switch unit 41 changes the state of each switch so as to output the detection signal of the light receiving element 36 as an ABS phase detection signal.
In addition, although illustration is abbreviate | omitted in FIG. 2, the switching part 4 switches the state of the period T2 to the period T5 in order between the period T1 and the period T6 according to a switching signal. Periods T2 to T5 indicate a state in which the switching unit 4 outputs the detection signals of the light receiving elements 32 to 35 as ABS phase detection signals in response to the switching signal.

  As described above, the switching unit 4 changes the state of the switch unit 41 in order from the period T1 to the period T6, and sequentially outputs the detection signals of the light receiving elements 31 to 36 as the ABS phase detection signal.

Next, the operation of adjustment control by the adjustment control unit 60 in the present embodiment will be described.
FIG. 3 is a diagram illustrating the adjustment operation of the detection signal of the encoder 100 according to the present embodiment.
3, in order from the top, (a) an ABS pattern, (b) an ABS phase detection signal, (c) a gain adjustment signal, (d) an ABS phase detection signal after amplification, and (e) a binarized signal are shown. ing. (A) The ABS pattern indicates a pattern corresponding to the detection signal selected by the switching unit 4 among the patterns in the absolute pattern 21. Further, (d) the amplified ABS phase detection signal indicates the output signal of the amplifier 51.
In this figure, (a) the vertical axis of the ABS pattern indicates the logical state of the pattern, and the vertical axes of (b) to (e) indicate the voltages, respectively. The horizontal axis indicates time.

  3 are the same as the periods T1 to T6 described above with reference to FIG. Here, waveforms W1 to W4 show waveforms when the signals from (b) to (e) are switched in order from the period T1 to the period T6.

In FIG. 3, the absolute pattern 21 has patterns indicating, for example, “1”, “1”, “0”, “1”, “0”, “0”. An example in the case of being in the position where the pattern is detected will be described.
In this case, the light receiving elements (31, 32, 34) output detection signals corresponding to “1”, and the light receiving elements (33, 35, 36) output detection signals corresponding to “0”.

  Next, the switching unit 4 changes the state of the switch unit 41 in order from the period T1 to the period T6 in accordance with the switching signal supplied from the absolute address processing unit 71, and (b) ABS phase detection in FIG. A signal (waveform W1) is output. The switching unit 4 sequentially outputs detection signals having different output characteristics (for example, maximum signal level) as ABS phase detection signals according to the light receiving elements 31 to 36, as indicated by the waveform W1. Here, the reason why the output characteristics differ depending on the light receiving elements 31 to 36 is that, as described above, the distance of the optical path from the light source 10 to the light receiving elements 31 to 36 through the absolute pattern 21 is the arrangement of the light receiving elements 31 to 36. This is because nonuniformity occurs in the signal level of the detection signal output from the light receiving elements 31 to 36.

  Here, the amplitude of the detection signal in the light receiving element 31 is the amplitude L1, the amplitude of the detection signal in the light receiving element 32 is the amplitude L2, the amplitude of the detection signal in the light receiving element 33 is the amplitude L3, and each amplitude is (amplitude L1 <amplitude L2 <Amplitude L3). The amplitude of the detection signal at the light receiving element 34 is the amplitude L4, the amplitude of the detection signal at the light receiving element 35 is the amplitude L5, the amplitude of the detection signal at the light receiving element 36 is the amplitude L6, and each amplitude is (amplitude L4> amplitude L5> Amplitude L6).

Next, the adjustment control unit 60 synchronizes with the switching signal supplied from the absolute address processing unit 71, and sends adjustment information corresponding to the light receiving elements (31 to 36) selected by the switching signal from the nonvolatile storage unit 14. read out. Based on the adjustment information read from the nonvolatile storage unit 14 in synchronization with the switching signal supplied from the absolute address processing unit 71, the adjustment control unit 60 applies a voltage corresponding to the adjustment information to the D / A unit 61. Output as a gain adjustment signal. That is, the D / A unit 61 outputs the gain adjustment signal (waveform W2) in FIG. 3C and changes the gain (gain) of the amplifier 51. Accordingly, the adjustment control unit 60 causes the signal conversion unit 5 to adjust the detection signal so that the output characteristics of the six detection signals detected by the six light receiving elements 31 to 36 are matched.
Here, as shown in the waveform W2, (c) the gain adjustment signal has the lowest signal level in the period T3 and the period T4, and the highest signal level in the period T1 and the period T6. In addition, (c) the gain adjustment signal has a signal level between the signal levels of the periods T3 and T4 and the signal levels of the periods T1 and T6 in the periods T2 and T5.

Next, the amplifier 51 amplifies the ABS phase detection signal based on the gain adjustment signal supplied from the A / D unit 61, and the amplified signal as shown in the waveform W3 ((d) in FIG. 3 is adjusted). (ABS phase detection signal) is output to the binarization unit 52. Here, since the gain (gain) is adjusted by the gain adjustment signal supplied from the D / A unit 61, the waveform W3 has a signal amplitude L10 that is a difference between the maximum signal level VH and the minimum signal level VL. It becomes a constant value during the period T1 to the period T6.
In FIG. 3D, the voltage Vth indicates the threshold voltage of the binarization unit 52.

  Next, the binarization unit 52 binarizes the adjusted ABS phase detection signal supplied from the amplifier 51 based on the threshold voltage Vth, and uses the binarized signal (waveform W4) in FIG. A digital signal is supplied to the absolute address processing unit 71 of the signal processing unit 6. In FIG. 3E, “H” indicates the H level (logic state “1”), and “L” indicates the L level (logic state “0”).

  As described above, the encoder 100 according to the present embodiment adjusts the ABS phase detection signal (detection signals of the light receiving elements 31 to 36) by the signal adjustment unit 8, and then the binarization unit 52 performs binarization, and binarization. The digitized signal is supplied to the absolute address processing unit 71 of the signal processing unit 6.

  The absolute address processing unit 71 of the position detection unit 7 takes in the binarized signal supplied from the binarizing unit 52 in order from the state of the period T1 to the state of the period T6, and 6-bit data corresponding to the absolute pattern 21 “110100” is acquired. The absolute address processing unit 71 performs code conversion on the acquired 6-bit data “110100” to generate absolute position information, and supplies the generated absolute position information to the composition processing unit 73. The interpolation processing unit 72 generates relative position information based on the A phase detection signal and the A phase detection signal supplied from the A / D unit (62, 63), and combines the generated relative position information with the synthesis processing unit. 73. Then, the composition processing unit 73 performs composition processing on the absolute position information supplied from the absolute address processing unit 71 and the relative position information supplied from the interpolation processing unit 72, and performs position information (for example, rotation). Body position).

As described above, in the encoder 100 according to the present embodiment, the code plate 2 has a pattern (for example, absolute pattern 21) indicating position information of a driven body (for example, a rotor), and a plurality of light receiving elements. (31 to 36) detects the absolute pattern 21 of the code plate 2. The signal converter 5 converts detection signals detected by the plurality of light receiving elements (31 to 36) into binary signals. The adjustment control unit 60 causes the signal conversion unit 5 to adjust the detection signal for each light receiving element (31 to 36) based on the adjustment information determined for each light receiving element (31 to 36).
Thereby, non-uniformity (variation) of the detection signal between the light receiving elements 31 to 36 is reduced, so that the encoder 100 according to the present embodiment can increase the conversion margin of binarization by the binarization unit 52. Therefore, for example, when a disturbance such as noise occurs, the encoder 100 according to the present embodiment can reduce erroneous conversion by the binarization unit 52. Therefore, the encoder 100 according to the present embodiment can reduce erroneous detection of the position of the driven body. Therefore, the encoder 100 in this embodiment can improve the reliability of detecting position information.

In addition, the encoder 100 according to the present embodiment includes a switching unit 4 that switches which one of the plurality of light receiving elements (31 to 36) outputs a detection signal. Based on the adjustment information corresponding to the light receiving elements (31 to 36) switched by the switching unit 4, the adjustment control unit 60 detects the detection signals (ABS phase detection signals) output from the switched light receiving elements (31 to 36). ) Is adjusted by the signal conversion unit 5 (or the signal adjustment unit 8).
Thereby, in the encoder 100 according to the present embodiment, the switching unit 4 outputs one detection signal of the plurality of light receiving elements (31 to 36) as the ABS phase detection signal, so that the signal conversion unit 5 is combined into one. Can be reduced. Therefore, the encoder 100 according to the present embodiment can reduce erroneous detection of the position of the driven body while reducing the signal conversion unit 5 to one.

In the present embodiment, the adjustment control unit 60 causes the signal conversion unit 5 to match the output characteristics of the plurality of detection signals detected by the plurality of light receiving elements (31 to 36) based on the adjustment information. Adjust the detection signal.
Thereby, non-uniformity (variation) in the output characteristics of the plurality of detection signals is reduced, so that the binarization conversion margin by the binarization unit 52 can be increased. Therefore, the encoder 100 according to the present embodiment can reduce erroneous detection of the position of the driven body.

In the present embodiment, the output characteristics of the plurality of detection signals include the maximum signal level (VH) of the detection signal or the minimum signal level (VL) of the detection signal. Based on the adjustment information, the adjustment control unit 60 causes the signal conversion unit 5 to adjust the detection signal so that the maximum signal level (VH) or the minimum signal level (VL) in the plurality of detection signals is matched.
Thereby, non-uniformity (variation) of the maximum signal level (VH) or the minimum signal level (VL) of the plurality of detection signals is reduced, so that the binarization conversion margin by the binarization unit 52 can be increased. . Therefore, the encoder 100 according to the present embodiment can reduce erroneous detection of the position of the driven body.

In this embodiment, the signal converter 5 includes an amplifier 51 that amplifies the detection signal, and a binarization unit 52 that converts the detection signal (ABS phase detection signal) amplified by the amplifier 51 into a binarized signal. It has. The adjustment control unit 60 causes the signal conversion unit 5 to adjust the detection signal by changing the gain of the amplifier 51 based on the adjustment information.
For example, in a conventional encoder, an amplified ABS phase detection signal as shown by a waveform W5 in FIG. 3D is used as a binarized detection signal. Therefore, when a noise signal such as noise NZ1 is mixed in the ABS phase detection signal in the period T1 in FIG. 3, the amplified ABS phase detection signal (waveform W5) temporarily changes across the threshold voltage Vth. . Thereby, in the conventional encoder, erroneous conversion occurs in binarization. That is, in the conventional encoder, there is a possibility that the position of the driven body is erroneously detected.

  On the other hand, in the encoder 100 according to the present embodiment, the binarization unit 52 uses the amplified ABS phase detection signal (waveform W3) in FIG. 3D as a detection signal for binarization. Therefore, even if a noise signal such as noise NZ1 is mixed in the ABS phase detection signal in the period T1 in FIG. 3, the amplified ABS phase detection signal (waveform W3) crosses the threshold voltage Vth. It does not change. In other words, the binarization conversion margin by the binarization unit 52 can be increased by changing the gain of the amplifier 51 based on the adjustment information. Therefore, the encoder 100 according to the present embodiment can reduce erroneous detection of the position of the driven body.

In addition, the encoder 100 according to the present embodiment includes a nonvolatile storage unit 14 that stores adjustment information determined for each of the light receiving elements (31 to 36). The adjustment control unit 60 adjusts the detection signal for each light receiving element (31 to 36) based on the adjustment information stored in the nonvolatile storage unit 14.
As a result, the adjustment control unit 60 adjusts the detection signal for each light receiving element (31 to 36) based on the adjustment information read from the nonvolatile storage unit 14, so that the detection signal is received by the light receiving element (31) with a simple configuration. 31 to 36).
Moreover, since the non-volatile memory | storage part 14 is a rewritable non-volatile memory, adjustment information can be changed easily. Here, the adjustment information may be information determined by design based on the irradiation characteristics of the light source 10, or may be information determined based on measurement by the adjustment information setting unit 210 of the setting device 200. In this case, since the adjustment information can be easily changed, the encoder 100 according to the present embodiment can vary the output characteristics of the light source 10 or the light receiving elements 31 to 36 in the manufacturing process or the light source 10 or the light receiving elements (31 to 36). It is possible to cope with variations due to aging (aging).

[Second Embodiment]
Next, the encoder 100a in the second embodiment will be described.
FIG. 4 is a block diagram showing the encoder 100a according to the present embodiment.
In this figure, the same components as those in FIG. 1 are denoted by the same reference numerals, and the description thereof is omitted.
The encoder 100a in the second embodiment is different from the first embodiment in the control for adjusting the detection signals of the light receiving elements 31 to 36. The encoder 100a in the second embodiment adjusts the detection signals of the light receiving elements 31 to 36 by changing the DC offset (DC offset) of the offset adjustment type amplifier 51a.
Hereinafter, differences from the first embodiment of the encoder 100a in the second embodiment will be described.

4, the encoder 100a includes a code plate 2, a light receiving unit 3, a switching unit 4, a signal converting unit 5a, a signal processing unit 6a, a light source 10, a driver unit 11, an amplifier (12, 13), and a nonvolatile storage unit 14. It has.
The signal conversion unit 5 a includes an amplifier 51 a and a binarization unit 52.

  The amplifier 51a (amplifying unit) amplifies the ABS phase detection signal and outputs the amplified signal (ABS phase detection signal) to the binarization unit 52. The amplifier 51a is, for example, an offset adjustment type amplifier circuit, and changes the DC offset (DC offset) based on the offset adjustment signal supplied from the signal processing unit 6. Here, the DC offset is a signal level indicating an average value (center voltage) of the maximum signal level of the detection signal and the minimum signal level of the detection signal.

The signal processing unit 6a includes an adjustment control unit 60a, a D / A (digital / analog) unit 61, an A / D (analog / digital) unit (62, 63), and a position detection unit 7.
The adjustment control unit 60a causes the signal conversion unit 5a to adjust the detection signals of the light receiving elements 31 to 36 for each light receiving element (31 to 36) based on the adjustment information determined for each light receiving element (31 to 36). For example, the adjustment control unit 60a converts the detection signal output from the switched light receiving element (31 to 36) based on the adjustment information corresponding to the light receiving element (31 to 36) switched by the switching unit 4. Adjust to part 5a.

  For example, the adjustment control unit 60a reads the adjustment information stored in the nonvolatile storage unit 14. Based on the read adjustment information, the adjustment control unit 60a causes the signal conversion unit 5a to adjust the detection signal so that the output characteristics of the six detection signals detected by the six light receiving elements 31 to 36 are matched. For example, the output characteristic includes an average value (DC offset) of the maximum signal level of the detection signal and the minimum signal level of the detection signal. In this case, based on the read adjustment information, the adjustment control unit 60a sends the detection signal to the signal conversion unit 5a so that the average values of the maximum signal level and the minimum signal level of the six detection signals match. Let them adjust.

  For example, the adjustment control unit 60 a causes the D / A unit 61 to output a voltage corresponding to the adjustment information as an offset adjustment signal based on the adjustment information read from the nonvolatile storage unit 14. That is, the adjustment control unit 60a outputs an offset adjustment signal via the D / A unit 61, and adjusts the detection signal to the signal conversion unit 5a by changing the DC offset voltage (DC offset voltage) of the amplifier 51a. Let

  Here, the encoder 100a includes a signal adjustment unit 8a that adjusts the detection signals of the light receiving elements 31 to 36 for each of the light receiving elements (31 to 36) based on the adjustment information determined for each of the light receiving elements (31 to 36). I have. In FIG. 4, the signal adjustment unit 8a corresponds to a D / A unit 61 and an amplifier 51a.

Next, the operation of the encoder 100a in this embodiment will be described.
The operation of the encoder 100a in the present embodiment is basically the same as the operation in the first embodiment. Here, the operation of the adjustment control by the adjustment control unit 60a in the present embodiment will be described.
FIG. 5 is a diagram illustrating the adjustment operation of the detection signal of the encoder 100a in the present embodiment.
In FIG. 5, in order from the top, (a) an ABS pattern, (b) an ABS phase detection signal, (c) an offset adjustment signal, (d) an amplified ABS phase detection signal, and (e) a binarized signal are shown. ing. (A) ABS pattern and (b) ABS phase detection signal are the same as those in FIG.
In this figure, (a) the vertical axis of the ABS pattern indicates the logical state of the pattern as in FIG. 3, and the vertical axes of (b) to (e) indicate the voltages, respectively. The horizontal axis indicates time.

  Further, the period T1 to the period T6 in FIG. 5 is the same as the period T1 to the period T6 described with reference to FIG. Here, the waveform W1 and the waveforms W6 to W8 show waveforms when the signals from (b) to (e) are sequentially switched from the period T1 to the period T6.

  In FIG. 5, the adjustment control unit 60 a synchronizes with the switching signal supplied from the absolute address processing unit 71 and displays adjustment information corresponding to the light receiving elements (31 to 36) selected by the switching signal in the nonvolatile storage unit 14. Read from. Based on the adjustment information read from the nonvolatile storage unit 14 in synchronization with the switching signal supplied from the absolute address processing unit 71, the adjustment control unit 60a applies a voltage corresponding to the adjustment information to the D / A unit 61. And output as an offset adjustment signal. That is, the D / A unit 61 outputs the (c) offset adjustment signal (waveform W6) in FIG. 5 and changes the DC offset of the amplifier 51a. Thereby, the adjustment control unit 60a performs signal conversion so that the output characteristics of the six detection signals detected by the six light receiving elements 31 to 36 (here, the average value of the maximum signal level and the minimum signal level) match. The detection signal is adjusted by the unit 5a.

Here, as shown in the waveform W6, (c) the offset adjustment signal has the lowest signal level in the periods T3 and T4, and the highest signal level in the periods T1 and T6. Further, (c) the offset adjustment signal has a signal level between the signal levels of the periods T3 and T4 and the signal levels of the periods T1 and T6 in the periods T2 and T5.
In FIG. 5C, the voltage V0 indicates the offset signal level of the amplifier 51 in the first embodiment as the reference signal level of the offset adjustment signal. In the amplifier 51 in the first embodiment, the offset signal level is a fixed value at the voltage V0. The voltage V0 is the signal level of the offset adjustment signal. Further, for example, the offset adjustment signal is amplified so that the average value (DC offset value) of the maximum signal level and the minimum signal level in the period T3 and the period T4 of the waveform W1 matches the threshold voltage Vth after amplification by the amplifier 51a. This is a signal for setting the offset voltage 51a.

  Next, the amplifier 51a amplifies the ABS phase detection signal based on the offset adjustment signal supplied from the A / D unit 61, and an amplified signal as shown by the waveform W7 ((d) in FIG. (ABS phase detection signal) is output to the binarization unit 52. Here, since the DC offset value is adjusted by the offset adjustment signal supplied from the D / A unit 61, the waveform W7 has a constant average value between the maximum signal level and the minimum signal level in the period T1 to the period T6. Value.

  In FIG. 5D, the voltage Vth indicates the threshold voltage of the binarization unit 52, as in FIG. Here, the average value of the maximum signal level and the minimum signal level in the waveform W7 is a constant value in the period T1 to the period T6 and coincides with the threshold voltage Vth of the binarization unit 52. As described above, the adjustment control unit 60a matches the average value of the maximum signal level and the minimum signal level of the six detection signals detected by the six light receiving elements 31 to 36, and the average value is equal to the threshold voltage Vth. The detection signal is adjusted by the signal converter 5a so as to match.

  In the ABS phase detection signal after amplification, the amplitude corresponding to the light receiving element 31 is set as the amplitude L11, the amplitude corresponding to the light receiving element 32 is set as the amplitude L12, and the amplitude corresponding to the light receiving element 33 is set as the amplitude L13. Since each amplitude is amplified by a predetermined gain (gain), the relationship in FIG. 5B is reflected (amplitude L11 <amplitude L12 <amplitude L13). Similarly, assuming that the amplitude corresponding to the light receiving element 34 is the amplitude L14, the amplitude corresponding to the light receiving element 35 is the amplitude L15, and the amplitude corresponding to the light receiving element 36 is the amplitude L16, each amplitude is (amplitude L14> amplitude L15). > Amplitude L16).

  Next, the binarizing unit 52 binarizes the adjusted ABS phase detection signal supplied from the amplifier 51a based on the threshold voltage Vth, and uses the binarized signal (waveform W8) in FIG. A digital signal is supplied to the absolute address processing unit 71 of the signal processing unit 6a. In FIG. 5E, “H” indicates an H level (logic state “1”), and “L” indicates an L level (logic state “0”).

  Thus, the encoder 100a in this embodiment adjusts the ABS phase detection signal (the detection signals of the light receiving elements 31 to 36) by the signal adjustment unit 8a, and then the binarization unit 52 performs binarization, and the binary The digitized signal is supplied to the position detector 7 (absolute address processor 71) of the signal processor 6a. Since the operation of generating position information by the position detector 7 is the same as that of the encoder 100 in the first embodiment, the description thereof is omitted here.

As described above, in the encoder 100a according to the present embodiment, the adjustment control unit 60a matches the output characteristics of the plurality of detection signals detected by the plurality of light receiving elements (31 to 36) based on the adjustment information. As described above, the detection signal is adjusted by the signal converter 5a. The output characteristic includes an average value of the maximum signal level of each detection signal and the minimum signal level of the detection signal. Based on the adjustment information stored in the nonvolatile storage unit 14, the adjustment control unit 60a causes the signal conversion unit 5a to adjust the detection signal so that the average values of the plurality of detection signals match.
Thereby, non-uniformity (variation) of the average value in the plurality of detection signals is reduced, and thus the binarization conversion margin by the binarization unit 52 can be increased. Therefore, the encoder 100a in the present embodiment can reduce erroneous detection of the position of the driven body.

In the present embodiment, the signal converter 5a includes an amplifier 51a that amplifies the detection signal, and a binarization unit 52 that converts the detection signal (ABS phase detection signal) amplified by the amplifier 51a into a binary signal. It has. The adjustment control unit 60a causes the signal conversion unit 5a to adjust the detection signal by changing the DC offset voltage (DC offset voltage) of the amplifier 51a based on the adjustment information.
For example, in the encoder 100a in this embodiment, the binarization unit 52 uses the amplified ABS phase detection signal (waveform W7) in FIG. 5D as a detection signal for binarization. Therefore, in the period T1 in FIG. 5, for example, even when a noise signal such as the noise NZ1 is mixed in the ABS phase detection signal, the ABS phase detection signal does not change across the threshold voltage Vth. That is, the binarization conversion margin by the binarization unit 52 can be increased by changing the DC offset voltage (DC offset voltage) of the amplifier 51a based on the adjustment information. Therefore, the encoder 100a in the present embodiment can reduce erroneous detection of the position of the driven body.

[Third Embodiment]
Next, an encoder 100b according to the third embodiment will be described.
FIG. 6 is a block diagram showing the encoder 100b according to the present embodiment.
In this figure, the same components as those in FIGS. 1 and 4 are denoted by the same reference numerals, and the description thereof is omitted.
The encoder 100b in the third embodiment is different from the first embodiment and the second embodiment in the control for adjusting the detection signals of the light receiving elements (31 to 36). The encoder 100b in the third embodiment adjusts the detection signals of the light receiving elements (31 to 36) by changing the threshold voltage of the binarization unit 52a.
Hereinafter, a point different from the first embodiment of the encoder 100a in the third embodiment will be described.

In FIG. 6, the encoder 100b includes a code plate 2, a light receiving unit 3, a switching unit 4, a signal converting unit 5b, a signal processing unit 6b, a light source 10, a driver unit 11, an amplifier (12, 13), and a nonvolatile storage unit 14. It has.
The signal conversion unit 5b includes an amplifier 51b and a binarization unit 52a.

The amplifier 51b (amplifying unit) amplifies the ABS phase detection signal and outputs the amplified signal (ABS phase detection signal) to the binarization unit 52a. The amplifier 51b amplifies the ABS phase detection signal with a predetermined gain.
The binarization unit 52a is, for example, a comparator (comparator), and converts the ABS phase detection signal amplified by the amplifier 51b into a binarized signal based on a predetermined threshold voltage. The binarization unit 52a changes a predetermined threshold voltage based on the threshold adjustment signal supplied from the signal processing unit 6b. For example, when the signal level of the amplified ABS phase detection signal is equal to or higher than a predetermined threshold voltage that is changed based on the threshold adjustment signal, the binarization unit 52a outputs an H level as a binarization signal. . For example, when the signal level of the amplified ABS phase detection signal is less than a predetermined threshold voltage, the binarization unit 52a outputs an L level as a binarized signal. The binarization unit 52a supplies the converted binarized signal to the signal processing unit 6b.

The signal processing unit 6b includes an adjustment control unit 60b, a D / A (digital / analog) unit 61, A / D (analog / digital) units (62, 63), and a position detection unit 7.
The adjustment control unit 60b causes the signal conversion unit 5b to adjust the detection signals of the light receiving elements 31 to 36 for each light receiving element (31 to 36) based on the adjustment information determined for each light receiving element (31 to 36). For example, the adjustment control unit 60b converts the detection signals output from the switched light receiving elements (31 to 36) based on the adjustment information corresponding to the light receiving elements (31 to 36) switched by the switching unit 4. Adjust to part 5b.

For example, the adjustment control unit 60b reads the adjustment information stored in the nonvolatile storage unit 14. Based on the read adjustment information, the adjustment control unit 60b determines the average value of the maximum and minimum signal levels of the six detection signals detected by the six light receiving elements 31 to 36, and the threshold value of the binarization unit 52a. The signal conversion unit 5a adjusts the detection signal so as to match.
For example, the adjustment control unit 60b causes the D / A unit 61 to output a voltage corresponding to the adjustment information as a threshold adjustment signal based on the adjustment information read from the nonvolatile storage unit 14. That is, the adjustment control unit 60b outputs a threshold adjustment signal via the D / A unit 61 and changes the threshold voltage of the binarization unit 52a, thereby causing the signal conversion unit 5b to adjust the detection signal.

  Here, the encoder 100b includes a signal adjustment unit 8b that adjusts the detection signals of the light receiving elements 31 to 36 for each light receiving element (31 to 36) based on the adjustment information determined for each light receiving element (31 to 36). I have. In FIG. 6, the signal adjustment unit 8b corresponds to a D / A unit 61 and a binarization unit 52a.

Next, the operation of the encoder 100b in this embodiment will be described.
The operation of the encoder 100b in the present embodiment is basically the same as the operation in the first embodiment. Here, the operation of the adjustment control by the adjustment control unit 60b in the present embodiment will be described.
In FIG. 7, in order from the top, (a) an ABS pattern, (b) an ABS phase detection signal, (c) a threshold adjustment signal, (d) an amplified ABS phase detection signal, and (e) a binarized signal are shown. ing. (A) ABS pattern and (b) ABS phase detection signal are the same as those in FIG.
FIG. 7 is a diagram showing an adjustment operation of the detection signal of the encoder 100b in the present embodiment.
In this figure, (a) the vertical axis of the ABS pattern indicates the logical state of the pattern as in FIG. 3, and the vertical axes of (b) to (e) indicate the voltages, respectively. The horizontal axis indicates time.

  Further, the period T1 to the period T6 in FIG. 7 is the same as the period T1 to the period T6 described with reference to FIG. Here, the waveform W1, the waveform W9, the waveform W10, and the waveform W12 indicate the waveforms when the signals from (b) to (e) are sequentially switched from the period T1 to the period T6. A waveform W11 indicates a waveform indicating a binarization threshold in the binarization unit 52a when the state is sequentially switched from the period T1 to the period T6.

  In FIG. 7, the adjustment control unit 60 b synchronizes with the switching signal supplied from the absolute address processing unit 71, and sends adjustment information corresponding to the light receiving elements (31 to 36) selected by the switching signal to the nonvolatile storage unit 14. Read from. Based on the adjustment information read from the nonvolatile storage unit 14 in synchronization with the switching signal supplied from the absolute address processing unit 71, the adjustment control unit 60b applies a voltage corresponding to the adjustment information to the D / A unit 61. Output as a threshold adjustment signal. That is, the D / A unit 61 outputs the threshold adjustment signal (waveform W9) of FIG. 7C, and changes the threshold of the binarization unit 52a. Accordingly, the adjustment control unit 60b matches the average value of the maximum and minimum signal levels of the six detection signals detected by the six light receiving elements 31 to 36 with the threshold value of the binarization unit 52a. The signal conversion unit 5b adjusts the detection signal.

Here, as shown by the waveform W9, the threshold adjustment signal has the highest signal level in the period T3 and the period T4, and the lowest signal level in the period T1 and the period T6. In the threshold adjustment signal, the signal levels in the periods T2 and T5 are between the signal levels in the periods T3 and T4 and the signal levels in the periods T1 and T6.
In FIG. 7C, the voltage V1 indicates the voltage level of the threshold adjustment signal corresponding to the threshold Vth in the first embodiment as the reference signal level.

  Next, the amplifier 51b amplifies the ABS phase detection signal based on a predetermined gain (gain), and an amplified signal as shown in the waveform W10 ((d) the amplified ABS phase detection signal in FIG. 7). It outputs to the binarization part 52a. Here, since the waveform W10 amplifies the waveform W1 with a predetermined gain (gain), the waveform has the same shape as the waveform W1.

  In FIG. 7D, a waveform W11 indicates the adjusted threshold value of the binarization unit 52a. Further, the voltage Vth indicates the threshold voltage of the binarization unit 52 in the first embodiment, as in FIG. Similarly to FIG. 5D, the amplitudes L11 to L16 indicate the amplitudes corresponding to the respective light receiving elements 31 to 36 in the amplified ABS phase detection signal. The adjustment control unit 60b changes (adjusts) the threshold adjustment signal so that the threshold of the binarization unit 52a becomes the center voltage from the amplitude L11 to the amplitude L16, as shown by the waveform W11.

  Next, the binarizing unit 52a binarizes the adjusted ABS phase detection signal supplied from the amplifier 51b based on the threshold indicated by the waveform W11, and (e) the binarized signal (waveform in FIG. 7). W12) is supplied to the absolute address processing unit 71 of the signal processing unit 6b. In FIG. 7E, “H” indicates the H level (logic state “1”), and “L” indicates the L level (logic state “0”).

  As described above, the encoder 100b according to the present embodiment performs binarization by adjusting the threshold value of the binarization unit 52a by the signal adjustment unit 8b, and converts the binarized signal to the position detection unit 7 (absolutely) of the signal processing unit 6b. To the address processing unit 71). Since the operation of generating position information by the position detector 7 is the same as that of the encoder 100 in the first embodiment, the description thereof is omitted here.

As described above, in the encoder 100b according to this embodiment, the signal conversion unit 5b has the amplifier 51b that amplifies the detection signal and the detection signal (ABS phase detection signal) amplified by the amplifier 51b at a predetermined threshold voltage. And a binarization unit 52a that converts the signal into a binarized signal. The adjustment control unit 60b causes the signal conversion unit 5b to adjust the detection signal by changing a predetermined threshold voltage of the binarization unit 52a based on the adjustment information (see waveform W11).
For example, in the encoder 100b in the present embodiment, the binarization unit 52a uses the amplitude as shown in the waveform W11 as a threshold for binarizing the amplified ABS phase detection signal (waveform W10) in FIG. A threshold value adjusted so as to be a center voltage having an amplitude L16 from L11 is used. Therefore, in the period T1 in FIG. 7, for example, even when a noise signal such as the noise NZ1 is mixed in the ABS phase detection signal, the ABS phase detection signal does not change across the threshold indicated by the waveform W11. That is, the conversion margin for binarization by the binarization unit 52a can be increased by changing the threshold voltage of the binarization unit 52a based on the adjustment information. Therefore, the encoder 100b in the present embodiment can reduce erroneous detection of the position of the driven body.

[Fourth Embodiment]
Next, an encoder 100c in the fourth embodiment will be described.
FIG. 8 is a block diagram showing the encoder 100c according to the present embodiment.
In this figure, the same components as those in FIG. 1 are denoted by the same reference numerals, and the description thereof is omitted.
The encoder 100c in the fourth embodiment is generated by interpolating adjustment information corresponding to the light receiving elements 31 to 36 from adjustment information corresponding to a part of the light receiving elements 31 to 36 in the first embodiment. And different.
Hereinafter, differences from the first embodiment of the encoder 100c in the fourth embodiment will be described.

8, the encoder 100c includes a code plate 2, a light receiving unit 3, a switching unit 4, a signal converting unit 5, a signal processing unit 6c, a light source 10, a driver unit 11, an amplifier (12, 13), and a nonvolatile storage unit 14. It has.
In addition, the non-volatile memory | storage part 14 in this embodiment memorize | stores the partial adjustment information which is the adjustment information corresponding to some of the light receiving elements 31-36.
The signal processing unit 6 c includes an adjustment control unit 60, a D / A (digital / analog) unit 61, an A / D (analog / digital) unit (62, 63), an adjustment information generation unit 64, and a position detection unit 7. It has.

  The adjustment information generation unit 64 generates adjustment information determined for each light receiving element (31 to 36) based on the partial adjustment information stored in the nonvolatile storage unit. The adjustment information generation unit 64 reads the partial adjustment information from the nonvolatile storage unit 14 and interpolates and generates adjustment information corresponding to each light receiving element located between the read partial adjustment information. For example, the adjustment information generation unit 64 may generate adjustment information corresponding to each light receiving element by linear interpolation from two values of the partial adjustment information, or may receive each light reception based on a predetermined function such as a quadratic function. Adjustment information corresponding to the element may be generated. The adjustment information generation unit 64 supplies the generated adjustment information to the adjustment control unit 60.

The adjustment control unit 60 according to the present embodiment sends detection signals to the light receiving elements (31 to 36) based on the adjustment information determined for the light receiving elements (31 to 36) generated by the adjustment information generating unit 64. To adjust. For example, the adjustment control unit 60 acquires the adjustment information from the adjustment information generation unit 64 in advance, and synchronizes the switching signal supplied from the absolute address processing unit 71 with the voltage corresponding to the adjustment information to the D / A unit 61. Output as a gain adjustment signal.
Other operations including the adjustment operation of the detection signal by the signal adjustment unit 8 and the operation of generating the position information by the position detection unit 7 are the same as those of the encoder 100 in the first embodiment, and thus description thereof is omitted here. .

As described above, the encoder 100 c in this embodiment includes the nonvolatile storage unit 14 and the adjustment information generation unit 64. The nonvolatile storage unit 14 stores partial adjustment information that is adjustment information corresponding to a part of the plurality of light receiving elements (31 to 36). The adjustment information generation unit 64 generates adjustment information determined for each light receiving element (31 to 36) based on the partial adjustment information stored in the nonvolatile storage unit. And the adjustment control part 60 adjusts a detection signal for every light receiving element (31-36) based on the adjustment information defined for every light receiving element (31-36) produced | generated by the adjustment information generation part 64. FIG.
Thereby, the encoder 100c in this embodiment can reduce erroneous detection of the position of the driven body, as in the first embodiment. Therefore, the encoder 100c in this embodiment can improve the reliability of detecting position information. Furthermore, since the encoder 100c in the present embodiment does not need to store adjustment information corresponding to all the light receiving elements in the nonvolatile storage unit 14, the storage capacity of the nonvolatile storage unit 14 can be reduced.

[Fifth Embodiment]
Next, an encoder 100d in the fifth embodiment will be described.
FIG. 9 is a block diagram showing the encoder 100d according to the present embodiment.
In this figure, the same components as those in FIG. 1 are denoted by the same reference numerals, and the description thereof is omitted.
The encoder 100d according to the fifth embodiment is different from the first embodiment in that the encoder 100d includes an adjustment information setting unit 15 that stores adjustment information in the nonvolatile storage unit 14.
Hereinafter, differences from the first embodiment of the encoder 100d in the fifth embodiment will be described.

  In FIG. 9, the encoder 100d includes a code plate 2, a light receiving unit 3, a switching unit 4, a signal converting unit 5, a signal processing unit 6, a light source 10, a driver unit 11, an amplifier (12, 13), a nonvolatile storage unit 14, And an adjustment information setting unit 15.

  The adjustment information setting unit 15 (setting unit) has the same function as the adjustment information setting unit 210 of the setting device 200 in the first embodiment. For example, the adjustment information setting unit 15 is configured so that the binarized signals binarized based on the detection signals of the six light receiving elements 31 to 36 are each at the H level (logic state “1”). Change the position of. For example, the adjustment information setting unit 15 binarizes based on the detection signals of the six light receiving elements 31 to 36 based on a command value from the driving device DR or the like during low-speed rotation in the maintenance mode or the like. The position of the code plate 2 is changed so that the binarized signals thus obtained are each at the H level (logic state “1”). The adjustment information setting unit 15 measures the voltage level of the node N1 that is the signal line of the ABS phase detection signal and the voltage level of the node N2 that is the output signal line of the amplifier 51 for each of the light receiving elements (31 to 36). Based on this, adjustment information for each light receiving element (31 to 36) is determined. That is, the adjustment information setting unit 15 measures the voltage of the node N1 and the voltage of the node N2 for each light receiving element (31 to 36), and based on the measurement result, the adjustment information for each light receiving element (31 to 36). Generate. The adjustment information setting unit 15 causes the nonvolatile storage unit 14 to store adjustment information generated for each light receiving element (31 to 36). Further, the adjustment information setting unit 15 may measure the voltage of the node N1 and the voltage of the node N2 for each light receiving element (31 to 36) to confirm whether the set adjustment information is set correctly.

Thus, the encoder 100d in the present embodiment includes the adjustment information setting unit 15 that measures the detection signal (ABS measurement signal and amplified ABS measurement signal) and determines adjustment information based on the measurement result. Yes.
Thereby, the encoder 100d in this embodiment can perform a calibration process (calibration process) regularly with an own apparatus. Therefore, the encoder 100d according to the present embodiment can reduce the possibility of erroneous detection of the position of the driven body due to variations due to aging (aging) of the light source 10 or the light receiving elements 31 to 36. . Therefore, the encoder 100c in this embodiment can improve the reliability of detecting position information.

[Sixth Embodiment]
Next, a drive device (motor device, actuator) including the encoder 100 (100a to 100d) 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 100 (100a to 100d) provided on the input shaft IAX (rotor 9). That is, the driving device DR includes an encoder 100 (100a to 100d) and a motor MTR (driving unit) that drives the input shaft IAX (driven body).

  The encoder 100 (100a to 100d) detects the rotational position (angular position) of the input shaft IAX (driven body), and outputs information including the rotational position as an encoder signal to a host controller that controls the driving device DR. To do. The host controller controls the drive device DR based on the encoder signal received from the encoder 100 (100a to 100d). Since the encoder 100 (100a to 100d) in the present embodiment can reduce erroneous detection of the rotational position of the input shaft IAX, the driving device DR in the present embodiment controls the position of the input shaft IAX of the motor MTR with high accuracy. be able to. Further, the driving device DR in the present embodiment can improve the reliability in position control.

  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 100 (100a to 100d) in this 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.
For example, in each of the above-described embodiments, the encoder 100 (100a to 100d) has been described with respect to the configuration in which the code plate 2 includes the transmission pattern, but the encoder 100 may include a reflection pattern. Further, the encoder 100 (100a to 100d) has been described with respect to the case where the detection element is an optical type. However, the present invention is not limited to this, and a form using a magnetic detection element may be used. Moreover, although the encoder 100 (100a-100d) demonstrated the case where it was a rotary type encoder, the form applied to a linear type encoder may be sufficient. In this case, the code plate 2 corresponds to a scale, and the rotor corresponds to a driven body such as a stage.

  Further, in each of the above-described embodiments, the mode in which the nonuniformity (variation) of the detection signals of the light receiving elements 31 to 36 is adjusted by the signal conversion unit 5 (5a, 5b) has been described. As long as it adjusts so that the nonuniformity (variation) of a detection signal may be reduced in any one of the paths from to the signal processing unit 6, other forms may be used. For example, the encoder 100 (100a to 100d) may include an adjustment unit that adjusts the detection signal non-uniformity separately from the signal conversion unit 5 (5a, 5b). In each of the above-described embodiments, the waveform of the adjustment signal or the waveform of the amplified signal may be a waveform having a signal polarity different from that of each of the above-described embodiments by using an inverting amplifier circuit in part or in whole.

  In the first to third embodiments, the detection signal adjustment method has been described as being used independently, but two or more of the first to third embodiments are used in combination. Form may be sufficient. For example, a mode in which the first embodiment and the second embodiment are used in combination (a mode in which gain and DC offset are combined and changed) may be used. In addition, for example, a mode in which the second embodiment and the third embodiment are used in combination (a mode in which an offset and a binarization threshold are combined and changed) may be used, or a mode in which another combination is used.

  Moreover, although the said 4th and 5th embodiment demonstrated the form applied to 1st Embodiment, the form applied to 2nd Embodiment or 3rd Embodiment may be sufficient. Moreover, the form which applies combining 4th Embodiment and 5th Embodiment may be sufficient.

  In each of the above embodiments, the encoder 100 (100a to 100d) has been described as having the switching unit 4. However, the amplifier 51 (equal to the number of detection elements (light receiving elements)) without the switching unit 4 is provided. 51a and 51b) and the binarization part 52 (52a) may be provided.

Further, in each of the above embodiments, the form applied to the encoder 100 (100a to 100d) has been described. However, the form applied to a position detection device such as a resolver device may be used.
In addition, the driving device DR in the present embodiment may be provided in a robot device such as an articulated robot having an arm or the like or a car (eg, an electric car).

  Further, in each of the above embodiments, each unit of the encoder 100 (100a to 100d) may be realized by dedicated hardware, and includes a memory and a CPU (central processing unit), and is controlled by a program. It may be realized.

  The above-described encoder 100 (100a to 100d) has a computer system therein. The processing steps of the encoder 100 (100a to 100d) 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.

  DESCRIPTION OF SYMBOLS 2 ... Code board, 4 ... Switching part, 5 ... Signal conversion part, 7 ... Position detection part, 9 ... Rotor, 15 ... Adjustment information setting part, 21 ... Absolute pattern, 31, 32, 33, 34, 35, 36 Light receiving element 51, 51a, 51b ... Amplifier, 52, 52a ... Binarization unit, 60 ... Adjustment control unit, 64 ... Adjustment information generation unit, 100, 100a, 100b, 100c, 100d ... Encoder, DR ... Drive device

Claims (12)

A code plate having a pattern indicating position information of the driven body;
A plurality of detection elements for detecting the pattern of the code plate;
A conversion unit that converts a detection signal detected by each of the plurality of detection elements into a binarized signal;
Based on adjustment information determined for each detection element, an adjustment control unit that causes the conversion unit to adjust the detection signal for each detection element;
An encoder comprising: a position detection unit configured to detect a position of the driven body based on the binarized signal. A switching unit for switching which detection element outputs the detection signal among the plurality of detection elements,
The adjustment control unit
The control unit according to claim 1, wherein the conversion unit adjusts the detection signal output from the switched detection element based on the adjustment information corresponding to the detection element switched by the switching unit. Encoder. The adjustment control unit
The detection signal is adjusted by the converter so that the output characteristics of the plurality of detection signals detected by the plurality of detection elements are matched based on the adjustment information. Item 3. The encoder according to item 2. The output characteristics include a maximum signal level of the detection signal or a minimum signal level of the detection signal,
The adjustment control unit
4. The encoder according to claim 3, wherein the conversion unit is configured to adjust the detection signal so that the maximum signal level or the minimum signal level in the plurality of detection signals matches based on the adjustment information. 5. . The output characteristic includes an average value of the maximum signal level of the detection signal and the minimum signal level of the detection signal,
The adjustment control unit
5. The encoder according to claim 3, wherein the conversion unit is configured to adjust the detection signal so that the average values of the plurality of detection signals are matched based on the adjustment information. The converter is
An amplifying unit for amplifying the detection signal;
A binarization unit that converts the detection signal amplified by the amplification unit into the binarized signal;
The adjustment control unit
The encoder according to any one of claims 1 to 5, wherein the conversion unit is configured to adjust the detection signal by changing a gain of the amplification unit based on the adjustment information. The converter is
An amplifying unit for amplifying the detection signal;
A binarization unit that converts the detection signal amplified by the amplification unit into the binarized signal;
The adjustment control unit
The encoder according to any one of claims 1 to 5, wherein the conversion unit is configured to adjust the detection signal by changing a DC offset voltage of the amplification unit based on the adjustment information. . The converter is
An amplifying unit for amplifying the detection signal;
A binarization unit that converts the detection signal amplified by the amplification unit into the binarization signal based on a predetermined threshold voltage, and
The adjustment control unit
The encoder according to claim 1 or 2, wherein the conversion unit is configured to adjust the detection signal by changing the predetermined threshold voltage of the binarization unit based on the adjustment information. A storage unit that stores the adjustment information determined for each detection element;
The adjustment control unit
The encoder according to any one of claims 1 to 8, wherein the detection signal is adjusted for each of the detection elements based on the adjustment information stored in the storage unit. A storage unit that stores partial adjustment information that is the adjustment information corresponding to a part of the plurality of detection elements;
An adjustment information generating unit that generates the adjustment information determined for each detection element based on the partial adjustment information stored in the storage unit, and
The adjustment control unit
The detection signal is adjusted for each of the detection elements based on the adjustment information determined for each of the detection elements generated by the adjustment information generation unit. The encoder according to one item. The encoder according to any one of claims 1 to 10, further comprising: a setting unit that measures the detection signal and determines the adjustment information based on the measurement result. The encoder according to any one of claims 1 to 11,
And a driving unit that drives the driven body.

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