JP2021076587A - Encoder device, use method therefor, positioning method, and position detection method - Google Patents

Abstract

To heighten the reliability of detection result of position information.MEANS FOR SOLVING THE PROBLEM: Provided is an encoder device comprising: a first detection unit for irradiating the pattern of a moving part with light, detecting light from the pattern, and outputting a first and a second detection signal mutually differing in phase with regard to the movement of the moving part; a second detection unit for irradiating the pattern with light, detecting light from the pattern and outputting a third detection signal and arranged at a different position than the first detection part along the movement direction of the moving part; a control part for switching between a state in which the movement information of the moving part is obtained by the first and second detection signals and a state in which the movement information is obtained by one of the first and second detection signals and the third detection signal; and an arithmetic part for finding the movement information by the detection signals in the state to which having been switched by the control unit.SELECTED DRAWING: Figure 2

Description

The present invention relates to an encoder device, a method of using the encoder device, a method of positioning the encoder device, a position detection method using the encoder device, a drive device, a stage device, and a robot device.

Encoder devices that detect position information such as the rotation angle or rotation speed of the test object are mounted on various devices such as robot devices. As a conventional encoder device, a device is known in which a pattern is illuminated by a light emitting element, light from the pattern is received by a light receiving element, and a power source for backup is provided (see, for example, Patent Document 1).
The encoder device as described above is desired to improve the reliability of the detection result.

Japanese Unexamined Patent Publication No. 10-073458

According to the first aspect, the first detection unit that irradiates the pattern of the moving unit with light, detects the light from the pattern, and outputs the first detection signal and the second detection signal, and the first detection thereof. A second detection unit that is arranged at different positions along the movement direction of the movement unit with respect to the unit, irradiates the pattern with light, detects the light from the pattern, and outputs a third detection signal, and the second detection unit thereof. An encoder including a first detection signal, a second detection signal thereof, and a calculation unit for obtaining movement information of the moving portion by two detection signals having different phases with respect to the movement of the moving portion among the second detection signal and the third detection signal. Equipment is provided.

According to the second aspect, a drive device including the encoder device of the first aspect and a power supply unit for supplying power to the moving unit thereof is provided.
According to the third aspect, a stage device including a moving object and a driving device of the second aspect for moving the moving object is provided.
According to the fourth aspect, a robot device including the drive device of the second aspect and an arm that is relatively moved by the drive device is provided.

According to the fifth aspect, the first detection unit that irradiates the pattern of the moving unit with light, detects the light from the pattern, and outputs the first detection signal and the second detection signal, and the first detection thereof. A second detection unit that is arranged at different positions along the movement direction of the movement unit with respect to the unit, irradiates the pattern with light, detects the light from the pattern, and outputs a third detection signal, and the second detection unit thereof. An encoder including a first detection signal, a second detection signal thereof, and a calculation unit for obtaining movement information of the moving portion by two detection signals having different phases with respect to the movement of the moving portion among the second detection signal and the third detection signal. A method of using the device, the detection signal of one of the first detection signal and the second detection signal, and the third detection signal whose phase is different from that of the other detection signal with respect to the movement direction of the moving portion. Provided is a method of using the encoder device, which comprises obtaining movement information of the moving portion using the above.

According to the sixth aspect, with respect to the first detection unit that detects light from the pattern provided along the movement direction of the rotating moving unit and outputs the first detection signal, and the first detection unit thereof. A second detection unit that is arranged at a predetermined angle along the movement direction of the movement unit, detects light from the pattern, and outputs a second detection signal, the first detection signal thereof, and the second detection unit thereof. A method for positioning an encoder device including a calculation unit that obtains rotation information of the moving unit based on a detection signal, and a support member that integrally supports the first detection unit and the second detection unit. A method for positioning an encoder device is provided, which comprises positioning a detection unit and a second detection unit thereof in a radial direction of rotational movement of the moving unit, respectively.

According to the seventh aspect, a first detection unit that detects light from a pattern provided along the movement direction of the rotating moving unit and outputs a first detection signal regarding the rotational movement of the moving unit, and a first detecting unit thereof. A second detection unit that is arranged at a predetermined angle away from the first detection unit along the movement direction of the movement unit, detects light from the pattern, and outputs a second detection signal, and a first detection unit thereof. A position detection method for an encoder device including a calculation unit that obtains rotation information of the moving unit by a detection signal and its second detection signal, and rotation information of the moving unit obtained from the first detection signal and its rotation information. Obtaining the error of the rotation information from the difference from the rotation information of the moving part obtained from the second detection signal, and using the first detection signal, the second detection signal, and the error to rotate the moving part. A method for obtaining information and detecting the position of the encoder device including the above is provided.

It is a figure which shows the encoder device which concerns on 1st Embodiment. FIG. 1A is a plan view showing a disk and a detection unit in FIG. 1, and FIG. 1B is a diagram showing a detection unit, a detection circuit unit, and the like in FIG. (A) is a diagram showing an example of the four detection signals of FIG. 2 (B), (B) is a diagram showing the transition of the states of the two sets of detection signals of FIG. 2 (B), and (C) is a normal detection. It is a figure which shows four states of a signal. It is a flowchart which shows an example of the usage method of the encoder device of 1st Embodiment. It is a flowchart which shows another example of the usage of the encoder device. (A) is a diagram showing a case where one of the four detection signals is abnormal, (B) is a diagram showing a case where two of the four detection signals are abnormal, and (C) is a combination of detection signals in which rotation information can be detected. It is a figure which shows the example of. (A) is a diagram showing a case where two of the four detection signals are abnormal, and (B) is a diagram showing an example of a state change corresponding to FIG. 7 (A). (A) is a plan view showing a modified example disk and a detection unit, and (B) is a diagram showing an example of four detection signals obtained from the detection unit of FIG. 8 (A). It is a figure which shows the encoder device of the modification. (A) is a plan view showing the mechanical part of the angle detection unit of the encoder device according to the second embodiment, (B) is a side view showing a part of FIG. 10 (A) in cross section, and (C) is a view. It is an enlarged plan view of the main part of 10 (A). It is a figure which shows the structure of the detection circuit part of the encoder device of 2nd Embodiment. (A), (B), (C), (D), (E), and (F) are diagrams showing an example of a plurality of signals in the detection circuit section of FIG. 11, and (G) is for adjusting the phase difference. It is a figure which shows the example of the absolute value detection signal when there is not (comparative example). (A) is a plan view in which a part of the detection units 11A and 11B is positioned with respect to the disk 6, and (B) is a position of a part of the pattern of the disk 6 and the detection units 11A and 11B. It is an enlarged plan view which shows an example of the state of deviation. (A) is a flowchart showing an example of the positioning method according to the second embodiment, and (B) is a flowchart showing an example of the detection method according to the third embodiment. It is a top view which shows an example of the arrangement of the 1st and 2nd detection part of the angle detection part of the encoder device which concerns on 2nd Embodiment. It is a figure which shows an example of a drive device. It is a figure which shows an example of a stage apparatus. It is a figure which shows an example of a robot device.

[First Embodiment]
The first embodiment will be described with reference to FIGS. 1 to 7. FIG. 1 shows an encoder device EC according to the present embodiment. In FIG. 1, the encoder device EC detects the rotation position information of the rotation axis SF (moving unit) of the motor M (power supply unit). The rotary shaft SF is, for example, a shaft (rotor) of the motor M, but is an action shaft (output shaft) connected to the shaft of the motor M via a power transmission unit such as a transmission and connected to a load. You may. The rotation position information detected by the encoder device EC is supplied to the motor control unit 26. The main control unit 27 of the motor control unit 26 controls the rotation (for example, rotation position, rotation speed, etc.) of the motor M by using the rotation position information supplied from the encoder device EC. The motor control unit 26 controls the rotation of the rotation shaft SF.

The encoder device EC includes a position detection system (position detection unit) 2 that detects the rotation position information of the rotation axis SF. The encoder device EC is a so-called multi-rotation absolute encoder. The position detection system 2 includes a multi-rotation information detection unit 3 that detects multi-rotation information indicating the number and direction of rotation of the rotation axis SF, and a rotation including angular position information indicating an angular position (rotation angle) of less than one rotation. The angle detection unit 4 for detecting the position information is provided.

As an example, at least a part of the position detection system 2 (for example, the angle detection unit 4) is a power source (hereinafter referred to as a main power source) of a device (for example, a drive device, a stage device, a robot device) on which the encoder device EC is mounted. It operates by receiving power from its main power supply while it is supplying power. Further, as an example, at least a part of the position detection system 2 (for example, the multi-rotation information detection unit 3) is in a state where the main power supply is supplying electric power (power-on state) and the main power supply is supplying electric power. It operates by receiving power from the battery 15 in a non-powered state (power off state, backup state, etc.).

The battery 15 includes, for example, a primary battery (button battery or the like) and a rechargeable secondary battery. A switching unit 16 is connected to the battery 15. The power supply unit MCE of the motor control unit 26 is a part of the main power supply. When the power supply unit MCE is supplying power (power is on), the power supply unit MCE charges the secondary battery of the battery 15. Then, the switching unit 16 supplies the electric power from the secondary battery to the multi-rotation information detection unit 3. On the other hand, when the power supply unit MCE is not supplying power (power off state), the secondary battery is not charged. When the remaining power of the secondary battery is large in this state, the switching unit 16 may supply the power from the secondary battery to the multi-rotation information detection unit 3. Further, when the power is off and the remaining power of the secondary battery is low, the switching unit 16 may supply the power from the primary battery to the multi-rotation information detection unit 3. Therefore, even when the power is off, the position detection system 2 (multi-rotation information detection unit 3) can detect at least a part (here, multi-rotation information) of the rotation position information of the rotation axis SF.

The multi-rotation information detection unit 3 optically detects the multi-rotation information as an example. The multi-rotation information detection unit 3 detects the first detection unit 10A and the pattern 8S for detecting the multi-rotation information detection pattern 8S formed on the disk-shaped disk 6 connected to the rotation axis SF at different positions. It has a second detection unit 10B and a detection signal processing unit 12. The detection signal processing unit 12 includes a control unit 13, for example, a storage unit 14 made of a non-volatile memory, and the above-mentioned battery 15 and switching unit 16. The disk 6 is fixed to a disk 5 attached to the rotating shaft SF by bolts 17 (see FIG. 2A). Since the disk 5 rotates together with the rotation axis SF, the disk 6 rotates in conjunction with the rotation axis SF. In the detection signal processing unit 12, the control unit 13 processes the detection signals of the detection units 10A and 10B to detect the multi-rotation information of the rotation axis SF. The storage unit 14 stores the multi-rotation information detected by the control unit 13.

The angle detection unit 4 is an optical encoder as an example, and detects position information (angle position information) within one rotation of the disk 6. For example, in the case of an optical encoder, the angle detection unit 4 has a first detection unit 11A for detecting the light from the pattern 9S for detecting the angle position of the disk 6, and a second detection unit for detecting the light from the pattern 9S at different positions. It has a detection circuit unit 21 that processes the detection signals of the unit 11B and the detection units 11A and 11B to detect an angular position within one rotation of the rotation axis SF. Pattern 9S includes, for example, absolute scales and incremental scales. Regarding the angle detection unit 4, the second detection unit 11B may be omitted.

The detection circuit unit 21 detects the angular position of the first resolution by using the result of detecting the light from the absolute scale, for example. Further, the detection circuit unit 21 detects the angle position of the second resolution higher than the first resolution by performing the interpolation calculation at the angle position of the first resolution using the result of detecting the light from the incremental scale. To do. Further, the disk 6 may be, for example, a member integrated with the disk 5. Further, although the multi-rotation information detection unit 3 and the angle detection unit 4 are each of a reflection type optical type, for example, they may be configured by a transmission type optical type encoder.

In the present embodiment, the encoder device EC includes a signal synthesis unit 22. The signal synthesis unit 22 calculates and processes the detection result by the position detection system 2. The signal synthesis unit 22 includes a synthesis unit 23 and a data communication unit 24. The synthesis unit 23 acquires the angle position information of the second resolution detected by the detection circuit unit 21. Further, the synthesis unit 23 acquires the multi-rotation information of the rotation axis SF from the storage unit 14 of the multi-rotation information detection unit 3. The synthesis unit 23 synthesizes the angle position information from the detection circuit unit 21 and the multi-rotation information from the multi-rotation information detection unit 3 to calculate the rotation position information. For example, when the detection result of the detection circuit unit 21 is θ (rad) and the detection result of the multi-rotation information detection unit 3 is n rotations, the synthesis unit 23 uses (2π × n + θ) (rad) as the rotation position information. ) Is calculated. The rotation position information may be information that is a combination of multi-rotation information and angle position information of less than one rotation.

The synthesis unit 23 supplies the rotation position information to the data communication unit 24. The data communication unit 24 is communicably connected to the communication unit MCC of the motor control unit 26 by wire or wirelessly. The data communication unit 24 supplies the rotation position information in digital format to the communication unit MCC of the motor control unit 26. The main control unit 27 of the motor control unit 26 acquires rotation position information from the data communication unit 24, for example, at a predetermined sampling rate. The main control unit 27 controls the rotation of the motor M by controlling the electric power (driving power) supplied to the motor M using the rotation position information.

Next, the multi-rotation information detection unit 3 of the present embodiment will be described.
FIG. 2A is a plan view showing the disc 6 and the detection units 10A and 10B in FIG. 1, and FIG. 2B is a diagram showing the detection units 10A and 10B and the control unit 13 and the like in FIG. As shown in FIG. 2 (A), on the surface of the disc 6, the reflective first pattern 8A and the second pattern 8B are formed by halving four concentric rings around the center of rotation, respectively. , The third pattern 8C, and the fourth pattern 8D are formed. That is, each of the patterns 8A to 8D is a half-ring band-shaped pattern having an opening angle of 180 °, the diameter of the first pattern 8A is the largest, and the diameters of the second pattern 8B, the third pattern 8C, and the fourth pattern 8D are in that order. Is gradually set smaller. Further, the second pattern 8B is an arrangement in which the first pattern 8A is rotated by 180 ° around the center of rotation, and the third pattern 8C and the fourth pattern 8D are the first pattern 8A and the second pattern 8A around the center of rotation, respectively. The pattern 8B is rotated 90 ° clockwise. Patterns 8A to 8D correspond to patterns 8S in FIG. Patterns 9S for the angle detection unit 4 of FIG. 1 are formed on the outside of the patterns 8A to 8D.

The first detection unit 10A is arranged so as to face the patterns 8A to 8D, and the second detection unit 10B arranges the first detection unit 10A at a position rotated 90 ° clockwise around the rotation center of the disk 6. Has been done.
As shown in FIG. 2B, the first detection unit 10A is from a light emitting diode (hereinafter referred to as LED) 31 that irradiates patterns 8A to 8D with light for detection, and patterns 8A, 8B, 8C, and 8D. It has light receiving elements 32A, 32B, 32C, and 32D that receive reflected light. Further, the first detection unit 10A digitizes the difference between the analog comparator 33A for obtaining the detection signal MA1 obtained by digitizing the difference between the signals output from the light receiving elements 32A and 32B and the signal output from the light receiving elements 32C and 32D. It has an analog comparator 33B for obtaining the detected detection signal MB1. The detection signals MA1 and MB1 are supplied to the arithmetic control unit 40 of the control unit 13. The arithmetic control unit 40 includes a counter 40a, a determination unit 40b, and a storage unit (details will be described later). As shown in FIG. 3A, the detection signals MA1 and MB1 are rectangular wave signals having a period in which the disk 6 makes one rotation (rotation angle is 360 °) as one cycle, and are detection signals with respect to the detection signal MA1. The phase of MB1 is shifted by 90 °. The horizontal axis of FIG. 3A is time t. The detection signal of FIG. 3A is a signal obtained when the disk 6 of FIG. 2A is rotated counterclockwise (hereinafter referred to as a forward direction).

Similarly, the second detection unit 10B includes a light emitting diode (hereinafter referred to as LED) 34 that irradiates the patterns 8A to 8D with light for detection, and a light receiving element that receives the reflected light from the patterns 8A, 8B, 8C, and 8D. It has 35A, 35B, 35C, and 35D. Any light emitting element such as a semiconductor laser can be used instead of the LEDs 31 and 34. As the light receiving elements 32A to 32D and 35A to 35D, for example, a photodiode can be used.

Further, the second detection unit 10B digitizes the difference between the analog comparator 36A for obtaining the detection signal MA2 obtained by digitizing the difference between the signals output from the light receiving elements 35A and 35B and the signal output from the light receiving elements 35C and 35D. It has an analog comparator 36B for obtaining the detected detection signal MB2. The detection signals MA2 and MB2 are also supplied to the arithmetic control unit 40 of the control unit 13. As shown in FIG. 3A, the detection signals MA2 and MB2 are rectangular wave signals having a period in which the disk 6 rotates once, and the phase of the detection signal MB2 is shifted by 90 ° with respect to the detection signal MA2. doing. Further, in the present embodiment, the position of the second detection unit 10B is 90 ° different from the position of the first detection unit 10A. Therefore, the phases of the detection signals MA2 and MB2 are shifted by 90 ° with respect to the detection signals MA1 and MB1. In the present embodiment, the phase of the detection signal MA2 is substantially equal to the phase of the detection signal MB1, and the phase of the detection signal MB2 is substantially 180 ° different from the phase of the detection signal MA1.

In FIG. 2B, the control unit 13 includes an arithmetic control unit 40 and a light emission control unit 39 that outputs drive signals 31L and 34L for causing the LEDs 31 and 34 to emit light. As an example, the light emission control unit 39 further supplies the sampling signal SS for detecting the detection signals MA1 to MB2 to the arithmetic control unit 40. The arithmetic control unit 40 reads the detection signals MA1 to MB2 in synchronization with the sampling signal SS. When the light emission control signals LE1 and LE2 supplied to the light emission control unit 39 by the arithmetic control unit 40 are set to high levels (usually low levels), the light emission control unit 39 may stop the light emission of the LED 31 or 34. it can.

In the state where the first detection unit 10A is operating normally (the detection signals MA1 and MB1 are normal), the counter 40a in the arithmetic control unit 40 is the detection signal MA1 read from the first detection unit 10A. Multi-rotation information of the rotation axis SF can be obtained using MB1. For example, if the detection signal MB1 is at the low level when the detection signal MA1 changes from the low level to the high level, an up signal for increasing the rotation speed by 1 is supplied to the storage unit 14. On the other hand, if the detection signal MB1 is at a high level when the detection signal MA1 changes from a low level to a high level, a down signal for reducing the rotation speed by 1 is supplied to the storage unit 14. By increasing or decreasing the rotation speed stored up to that point by the storage unit 14, the rotation speed (multi-rotation information) of the rotation axis SF can be accurately obtained.

Further, in the state where the second detection unit 10B is operating normally, the counter 40a in the arithmetic control unit 40 also uses the detection signals MA2 and MB2 read from the second detection unit 10B to similarly rotate the axis. It is possible to obtain SF multi-rotation information. Further, the phases of the detection signals MB1 and MA2 are substantially the same, and the phases of the detection signals MA1 and MB2 are substantially 180 ° different (inverted). Therefore, even if the combination of the detection signal MA1 or MB2 and the detection signal MB or MA2 is used, the multi-rotation information of the rotation axis SF can be obtained respectively. In other words, it may be possible to obtain the multi-rotation information even when the detection units 10A and 10B are partially abnormal.

In the determination unit 40b in the arithmetic control unit 40, when any of the detection signals MA1 to MB2 is not normal but multi-rotation information can be detected, the first alarm signal AS1 is transmitted to the motor via the data communication unit 24 of FIG. It is transmitted to the main control unit 27 of the control unit 26. When at least two of the detection signals MA1 to MB2 are not normal and the multi-rotation information cannot be detected, the determination unit 40b transmits the second alarm signal AS2 to the main control unit 27 of the motor control unit 26. The main control unit 27 can perform processing according to the alarm signals AS1 and AS2.

Next, an example of the basic usage of the encoder device EC of the present embodiment will be described with reference to the flowchart of FIG. In the usage method, the determination unit 40b of the arithmetic control unit 40 in the control unit 13 determines whether the four detection signals MA1 to MB2 are normal, that is, whether they can be used to detect the multi-rotation information. To do. At that time, as an example, the combination and / or transition of the states of the detection signals MA1, MB1 and MA2, MB2 is examined. As shown in FIG. 3 (A), in the combination of the normal detection signals MA1 and MB1, the state 1 (hereinafter, represented by L) is such that MA1 is at a high level (hereinafter, represented by H) and MB1 is at a low level (hereinafter, represented by L). ST1), state 2 (ST2) where MA1 and MB1 are (H, H), state 3 (ST3) where MA1 and MB1 are (L, H), and state where MA1 and MB1 are (L, L). There is 4 (ST4). Similarly, for a combination of normal detection signals MA2 and MB2, state 1 (ST1) in which MA2 and MB2 are (L, L), state 2 (ST2) in which MA2 and MB2 are (H, L), and MA2 , MB2 is (H, H) in state 3 (ST3), and MA2 and MB2 are in (L, H) state 4 (ST4). Assuming that the period of the detection signals MA1 and MB1 is T1, the period T2 of each state is T1 / 4. As a general rule, if the detection signals MA1 and MB1 are in states 1 to 4, the detection signals MA2 and MB2 are also in the same states 1 to 4. The combination of the levels of the normal detection signals MA1 to MB2 in the states 1 to 4 is as shown in FIG. 3 (C).

When the disk 6 of FIG. 2 (A) rotates in the forward direction, as shown in FIG. 3 (B), the state transition 18A of the detection signals MA1 and MB1 and the state transition 18B of the detection signals MA2 and MB2 , State 1, state 2, state 3, state 4, state 1 in that order. When the disk 6 rotates in the opposite direction (clockwise), the state transitions 18A and 18B are in the order of state 1, state 4, state 3, state 2, and state 1. The patterns of the transitions 18A and 18B of this state are stored in a storage unit such as a ROM in the arithmetic control unit 40.

The determination unit 40b of the arithmetic control unit 40 can determine whether or not the detection signals MA1 to MB2 are normal based on the transition of the states of these detection signals as an example. For example, as shown in FIG. 6A, the levels of three detection signals MB1, MA2, MB2 among the four detection signals MA1 to MB2 are changing, while the other one detection signal MA1 If the level of is not changed (the state is not changed), the detection signal MA1 can be regarded as abnormal. Similarly, as shown in FIG. 6B, the levels of the two detection signals MA1 and MB2 among the four detection signals MA1 to MB2 are changing, while the other two detection signals MB1 and MB1 are changed. If the level of MA2 has not changed, the detection signals MB1 and MA2 can be regarded as abnormal.

Further, as another example, the determination unit of the arithmetic control unit 40 can determine whether or not the detection signals MA1 to MB2 are normal based on the combination of the states of these detection signals. For example, as shown in FIG. 7A, the levels of two detection signals MA1 and MB2 among the four detection signals MA1 to MB2 are changing, while the other two detection signals MB1 and MA2 are changed. When the level of is not changed, the combination of levels in the states 1 to 4 of the detection signals MA1 to MB2 is as shown in FIG. 7 (B). Comparing the combination of the detection signal levels (states) of FIG. 7 (B) with the combination of the normal detection signal levels of FIG. 3 (C), the combination of the levels of states 2 and 3 of FIG. 7 (B) is compared. Is different from the corresponding part in FIG. 3C (the levels of the detection signals MB1 and MA2 are different). From this comparison, it can be determined that the detection signals MB1 and MA2 are not normal.

Then, as a basic method of using the encoder device EC, in step 102 of FIG. 4, the light emission control unit 39 lights the LEDs 31 and 34 of the first detection unit 10A and the second detection unit 10B, and in step 104, arithmetic control is performed. The unit 40 reads the four detection signals MA1, MB1, MA2, and MB2 of the detection units 10A and 10B. Further, in step 108, the determination unit of the arithmetic control unit 40 determines whether or not the detection signal MA1 is normal by using the above-mentioned determination method, and if the detection signal MA1 is normal, the process proceeds to step 110 and the detection signal is detected. Determine whether MB1 is normal or not. When the detection signal MB1 is normal, the process proceeds to step 114, and the counter 40a of the arithmetic control unit 40 reads the detection signals MA1 and MB1 of the first detection unit 10A as valid (normal) detection signals. I do. In the next step 116, the counter of the arithmetic control unit 40 processes the read detection signals MA1 and MB1 to calculate the multi-rotation information (for example, the above-mentioned up signal or down signal) (rotation information) of the rotation axis SF. , The calculated information is stored in the storage unit 14. After that, the operations of steps 114 and 116 are repeated.

On the other hand, if the detection signal MB1 is not normal in step 110, the process proceeds to step 118, and the determination unit of the arithmetic control unit 40 determines whether or not the detection signal MA2 of the second detection unit 10B is normal. When the detection signal MA2 is normal, the process proceeds to step 114 in order to use the detection signal MA2 instead of the detection signal MB1, and the counter of the arithmetic control unit 40 is used as a valid detection signal by the first detection unit 10A. The detection signal MA1 and the detection signal MA2 of the second detection unit 10B are read. Then, in step 116, the counter of the arithmetic control unit 40 calculates the multi-rotation information using the detection signals MA1 and MA2, and stores the calculated information in the storage unit 14.

Further, in step 118, if the detection signal MA2 is not normal, the process proceeds to step 126 because the two detection signals necessary for obtaining the multi-rotation information do not exist. Then, the determination unit of the arithmetic control unit 40 transmits a second alarm signal AS2 (second alarm information) indicating that the rotation information cannot be detected to the main control unit 27 of the motor control unit 26 of FIG. In response to this, as an example, the main control unit 27 supplies information to the operator (not shown) that the multi-rotation information detection unit 3 of the encoder device EC is not normal, for example, the operator replaces the detection units 10A and 10B. Perform maintenance.

Further, in step 108, if the detection signal MA1 is not normal, the process proceeds to step 130, and the determination unit of the arithmetic control unit 40 determines whether or not the detection signal MB2 of the second detection unit 10B is normal. If the detection signal MB2 is normal, the process proceeds to step 110 in order to use the detection signal MB2 instead of the detection signal MA1. Then, when the detection signal MB1 or MA2 is normal, the process proceeds to step 114, and the counter of the arithmetic control unit 40 reads the detection signal MB2 and the detection signal MB1 (or MA2) as effective detection signals. Then, in step 116, the counter of the arithmetic control unit 40 calculates the multi-rotation information using the read detection signal, and stores the calculated information in the storage unit 14.

Further, in step 130, if the detection signal MB2 is not normal, the process proceeds to step 126 because the two detection signals necessary for obtaining the multi-rotation information do not exist. Then, the determination unit of the arithmetic control unit 40 transmits a second alarm signal AS2 indicating that the rotation information cannot be detected to the main control unit 27 of the motor control unit 26 of FIG. Summarizing the above operations, when the abnormal detection signal is the signal in the left column of the table in FIG. 6C, the combination of the two detection signals capable of detecting the multi-rotation information of the rotation axis SF is on the right side of the table. It looks like a column. In the table of FIG. 6C, when only the detection signal MA1 is not normal, the combination of the detection signals that can be detected is the detection signals MB2 and MB1 (or MA2), and when only the detection signal MB1 is not normal. , The combination of the detection signals that can be detected is the detection signals MA2 and MB2 (or MA1).

If the detection signals MB1 and MB2 are not normal, the combination of the detection signals that can be detected is the detection signals MA1 and MA2, and if the detection signals MA1 and MB1 are not normal, the combination of the detection signals that can be detected is. The detection signals MA2 and MB2. On the other hand, when the detection signals MA1 and MB2 are not normal, and when the detection signals MB1 and MA2 are not normal, there is no combination of detection signals that can be detected. In this case, in step 126, the determination unit (control unit 13) of the arithmetic control unit 40 outputs the second alarm signal AS2.

According to this usage method, for example, when one detection signal MA1 of the first detection unit 10A is normal and the other detection signal MB1 is not normal, the detection signal MA1 and the detection signal MA2 of the second detection unit 10B are used. The rotation information of the rotation axis SF can be obtained. Therefore, the reliability of the detection result of the rotation information can be improved. Further, when two of the four detection signals MA1 to MB2 having phases different from each other by 90 ° (or 270 °) are normal, rotation information can be detected using these two detection signals.

Next, another example of the usage method of the present embodiment will be described with reference to the flowchart of FIG. First, in step 102 of FIG. 5, the light emission control unit 39 turns on the LEDs 31 and 34 of the detection units 10A and 10B, and in step 104, the determination unit of the arithmetic control unit 40 sends the detection signals MA1 to MB2 of the detection units 10A and 10B. After being read, in step 106, the determination unit of the arithmetic control unit 40 confirms whether or not the detection signals MA1 to MB2 have a detection signal that has changed to a high level and / or a low level a plurality of times, and a plurality of detection signals MA1 to MB2. If there is no detection signal that has changed the number of times, the process returns to step 104. On the other hand, if there is a detection signal that has changed a plurality of times in step 106, the process proceeds to step 108, and the determination unit determines whether or not the detection signal MA1 is normal. Whether or not the detection signal MA1 or the like is normal can be determined based on the combination of the states of the detection signals or the transition of the states as described above.

If the detection signal MA1 is normal, the process proceeds to step 110, and the determination unit of the arithmetic control unit 40 determines whether or not the detection signal MB1 is normal. If the detection signal MB1 is normal, the process proceeds to step 112. The determination unit of the arithmetic control unit 40 sets the light emission control signal LE2 to a high level, and the light emission control unit 39 turns off the LED 34 of the second detection unit 10B accordingly. Then, in step 114, the counter of the arithmetic control unit 40 reads the detection signals MA1 and MB1 of the first detection unit 10A, and in step 116, the multi-rotation information (rotation information) of the rotation axis SF is calculated and stored. After this, steps 114 and 116 are repeated.

If the detection signal MB1 is not normal in step 110, the process proceeds to step 118, and the determination unit of the arithmetic control unit 40 determines whether or not the detection signal MA2 is normal. When the detection signal MA2 is normal, the process proceeds to step 120 to show that there is an abnormality in a part of the detection signals MA1 to MB2 (here, the detection signal MB1), but the rotation information can be detected. In addition, the determination unit of the arithmetic control unit 40 outputs the first alarm signal AS1 to the main control unit 27 of the motor control unit 26. In response to this, the main control unit 27 may provide the operator with information on an abnormal detection signal at the time of maintenance of the next encoder device EC, for example. In the next step 122, the arithmetic control unit 40 reads the detection signals MA1 and MA2, and in step 124, the detection signals MA1 and MA2 are used to calculate the multi-rotation information (rotation information) of the rotation axis SF, and the calculation result is obtained. It is stored in the storage unit 14. After that, steps 122 and 124 are repeated.

Further, in step 118, if the detection signal MA2 is not normal, there is no detection signal that can be used, so the operation shifts to step 126, and the determination unit of the arithmetic control unit 40 sends the second alarm signal AS2 to the main control unit 27. Is output, and the main control unit 27 can perform the corresponding processing described above. As a further example, in the next step 128, the determination unit of the arithmetic control unit 40 sets the light emission control signals LE1 and LE2 to a high level, and stops the detection of the rotation information. In response to this, the light emission control unit 39 turns off the LEDs 31 and 34.

Further, in step 108, if the detection signal MA1 is not normal, the process proceeds to step 130, and the determination unit of the arithmetic control unit 40 determines whether or not the detection signal MB2 is normal, and if the detection signal MB2 is normal, the step Moving to 132, the determination unit of the arithmetic control unit 40 determines whether or not the detection signal MB1 is normal. When the detection signal MB1 is normal, the process proceeds to step 134 to show that there is an abnormality in a part of the detection signals MA1 to MB2 (here, the detection signal MA1), but the rotation information can be detected. The determination unit of the arithmetic control unit 40 outputs the first alarm signal AS1 (first alarm information) to the main control unit 27 of the motor control unit 26. In the next step 136, the counter of the arithmetic control unit 40 reads the detection signals MB2 and MB1, and in step 138, the counter of the arithmetic control unit 40 uses the detection signals MB2 and MB1 to provide multi-rotation information of the rotation axis SF. Is calculated, and the calculation result is stored in the storage unit 14. After that, steps 136 and 138 are repeated.

Further, in step 132, if the detection signal MB1 is not normal, the process proceeds to step 140, and the determination unit of the arithmetic control unit 40 determines whether or not the detection signal MA2 is normal. When the detection signal MA2 is normal, the process proceeds to step 142 to show that there is an abnormality in a part of the detection signals MA1 to MB2 (here, the detection signals MA1 and MB1), but the rotation information can be detected. In addition, the determination unit of the arithmetic control unit 40 outputs the first alarm signal AS1 to the main control unit 27 of the motor control unit 26. In the next step 144, the determination unit of the arithmetic control unit 40 sets the light emission control signal LE1 to a high level, and the light emission control unit 39 turns off the LED 31 of the first detection unit 10A accordingly. Then, in step 146, the counter of the arithmetic control unit 40 reads the detection signals MA2 and MB2 of the second detection unit 10B, and in step 148, the counter calculates and stores the multi-rotation information (rotation information) of the rotation axis SF. I do. After this, steps 146 and 148 are repeated.

If the detection signal MA2 is not normal in step 140, and if the detection signal MB2 is not normal in step 130, there is no usable detection signal, and the process proceeds to step 150, respectively. Then, the determination unit of the arithmetic control unit 40 outputs the second alarm signal AS2 to the main control unit 27, and the main control unit 27 can perform the corresponding processing described above. As a further example, in the next step 152, the detection of the rotation information is stopped as in the step 128.

According to this usage method, when some of the detection signals of the first detection unit 10A and the second detection unit 10B are not normal, another normal detection signal is used instead to rotate the detection signal. Information can be requested with high reliability. Further, if the rotation information can be detected even if there is an abnormal detection signal, the first alarm signal AS1 is output, and if there are many abnormal detection signals and the rotation information cannot be detected, the second alarm signal AS2 is output. By outputting the first alarm signal AS1, for example, by taking measures such as postponing the maintenance, the maintenance of the encoder device EC (replacement of partial detectors, replacement of all detectors, etc.) Can be done efficiently.

As described above, the encoder device EC of the present embodiment irradiates the pattern 8S of the disk 5 of the rotating shaft SF (moving portion) with light, detects the light from the pattern 8S, and rotates (moves) the rotating shaft SF. The first detection unit 10A that outputs the first detection signal MA1 and the second detection signal MB1 that are out of phase with each other, and different positions along the rotation direction (movement direction) of the rotation axis SF with respect to the first detection unit 10A. The second detection unit 10B, which irradiates the pattern 8S with light, detects the light from the pattern 8S, and outputs the third detection signal MA2 and the fourth detection signal MB2, and the first detection signals MA1 and the second. A state in which rotation information (movement information) of the rotation axis SF is obtained by the detection signal MB1, one of the first detection signal MA1 and the second detection signal MB1, and the third detection signal MA2 (or the fourth detection signal MB2). Counting in the control unit 13 (or the determination unit 40b in the calculation control unit 40) that switches the state for obtaining the rotation information by the control unit 13 and the calculation control unit 40 that obtains the rotation information by the detection signal in the state switched by the control unit 13. It is equipped with a device 40a (calculation unit).

Further, the method of using the encoder device EC of the present embodiment includes a state in which the determination unit 40b obtains rotation information (movement information) of the rotation axis SF by the first detection signal MA1 and the second detection signal MB1 and a first detection signal. Steps 108, 110, 118, 130, 114 for switching between one of the MA1 and the second detection signal MB1 and the state for obtaining the rotation information by the third detection signal MA2 (or the fourth detection signal MB2), and the counter. It includes step 116 of obtaining the rotation information by the detection signal of the switched state by 40a. According to this embodiment, two detection units 10A and 10B are provided, and four detection signals are output. Therefore, even if an abnormality occurs in one detection signal, another normal detection signal is used. Therefore, the accuracy or reliability of the detection result of the rotation information of the rotation axis SF can be improved.

Further, in the present embodiment, when the rotation information is obtained by using the detection signals MA1 and MB2 of the first detection unit 10A, the LED 34 of the second detection unit 10B is turned off and the detection signals MA2 and MB2 of the second detection unit 10B are turned off. When obtaining rotation information using the above, the LED 31 of the first detection unit 10A may be turned off. In this case, the power consumption can be suppressed and the reliability of the detection result of the rotation information can be improved.

In the above-described embodiment, the following modifications are possible. First, in the above-described embodiment, as shown in FIG. 2A, the angle between the first detection unit 10A and the second detection unit 10B is 90 °. On the other hand, as shown in the modified example of FIG. 8A, the second detection unit 10B may be arranged on the disk 6 at an angle of 180 ° with respect to the first detection unit 10A. In this modification, it is assumed that the detection signals MA1 and MB1 obtained from the first detection unit 10A when the disk 6 is rotated are the two-phase rectangular wave signals shown in FIG. 8B. At this time, the detection signals MA2 and MB2 obtained from the second detection unit 10B are, for example, a rectangular wave signal in which the phase of the corresponding signal in FIG. 3A is shifted by 90 °, as shown in FIG. 8B. Become.

In this modified example, the combination of the detection signals MA1 and MB1 in the states 1 (ST1) to 4 (ST4) is the same as the example of FIG. 3 (A). On the other hand, the combinations of the detection signals MA2 and MB2 in the states 1 to 4 are (L, H), (L, L), (H, L) and (H, H), which are shown in FIG. 3 (A). It is different from the example of. In this modification, the detection signal MA2 having a phase difference of 180 ° can be used instead of the detection signal MA1, and the detection signal MB2 having a phase difference of 180 ° can be used instead of the detection signal MB1. Then, for example, when the detection signal MA1 is not normal, rotation information can be obtained using the detection signals MB1 and MA2.

Next, in the above-described embodiment, the four detection signals MA1 to MB2 are generated, but as shown in the encoder device ECA of the modified example of FIG. 9, the three detection signals MA1, MB1 and MA2 are generated. May be good. In FIG. 9, the parts corresponding to FIG. 2B are designated by the same reference numerals, and detailed description thereof will be omitted.
In FIG. 9, the configuration of the first detection unit 10A is the same as that of the first detection unit 10A in FIG. 2B. The second detection unit 10C includes an LED 34 that irradiates the patterns 8A and 8B with light for detection, and light receiving elements 35A and 35B that receive the reflected light from the patterns 8A and 8B. Further, the second detection unit 10C has an analog comparator 36A that obtains a detection signal MA2 that digitizes the difference between the signals output from the light receiving elements 35A and 35B. The detection signals MA1 and MB1 of the first detection unit 10A and the detection signals MA2 of the second detection unit 10C are supplied to the arithmetic control unit 40.

If the detection signals MA1 and MB1 are normal, the arithmetic control unit 40 can calculate the multi-rotation information of the rotation axis SF using the detection signals MA1 and MB1. Further, for example, when the detection signal MB1 is not normal, the arithmetic control unit 40 can calculate the multi-rotation information of the rotation axis SF by using the detection signals MA1 and MA2. Even in the modified example of generating the three detection signals in this way, the reliability of the detection result of the rotation information can be improved by using the normal detection signal instead of the abnormal detection signal.

In this modification, the three detection signals MA1, MB1 and MA2 shown in FIG. 2C are generated, but the three detection signals MA1, MB1 and MB2 shown in FIG. 2C may be generated.
Further, in the above-described embodiment, as shown in FIG. 2B, the two-phase detection signals MA1 and MB1 are obtained from the detection signals of the two light receiving elements 32A, 32B and 32C, 32D by using the analog comparators 33A and 33B. Similarly, the two-phase detection signals MA2 and MB2 are generated from the detection signals of the four light receiving elements 35A to 35D. On the other hand, for example, the two-phase detection signals MA1 and MB1 may be generated by comparing the detection signals of the light receiving elements 32A and 32C with the corresponding reference signals. Two-phase detection signals MA2 and MB2 can be generated in the same manner. In this case, the patterns 8B and 8D are omitted from the disk 6 of FIG. 2A, the light receiving elements 32B and 32D are omitted from the first detection unit 10A, and the light receiving elements 35B and 35D are omitted from the second detection unit 10. Therefore, the configuration of the disk 6 and the configurations of the detection units 10A and 10B can be simplified.

[Second Embodiment]
The second embodiment will be described with reference to FIGS. 10 to 14. The parts corresponding to FIGS. 1 to 2 (B) in FIGS. 10 to 13 are designated by the same reference numerals, and detailed description thereof will be omitted. 10 (A) is a plan view showing a mechanical portion of the angle detection unit 4 of the encoder device ECB according to the present embodiment, and FIG. 10 (B) is a side view and a view showing a part of FIG. 10 (A) as a cross section. 10 (C) is an enlarged plan view of a main part of FIG. 10 (A). The angle detection unit 4 is a part of the position detection system 2 of FIG. The angle detection unit 4 detects rotation position information (rotation information) including angle position (angle) information indicating a rotation angle of less than one rotation of the rotation axis SF (moving unit) connected to the motor M of FIG. The rotation information detected by the angle detection unit 4 is supplied to the motor control unit 26 via the synthesis unit 23 of FIG. The motor control unit 26 controls the rotation of the motor M (rotation axis SF) by using the rotation information and the like.

In FIGS. 10A and 10B, the disc 6 is fixed to the surface of the disk 5 at the tip of the rotating shaft SF by using bolts 17 and washers (washers) 17A. On the surface of the disk-shaped disk 6, a pattern 9S for angle detection including an incremental scale 9SI and an absolute scale 9SA is formed concentrically around the center (rotation center) of the rotation axis SF. The angle detection unit 4 processes the detection signals of the first detection unit 11A for detecting the light from the pattern 9S of the disk 6, the second detection unit 11B for detecting the light from the pattern 9S at different positions, and the detection units 11A and 11B. It has a detection circuit unit 21 (see FIG. 11) that detects an angle θ within one rotation of the rotation axis SF (disk 6). In the present embodiment, the position of the second detection unit 11B is deviated by 90 ° from the first detection unit 11A in the rotation direction (θ direction) of the rotation axis SF. Further, the detection units 11A and 11B and the detection circuit unit 21 are provided on the surface of the common disk-shaped substrate 50 facing the disk 6, and the substrate 50 is arranged between the substrate 50 and the disk 6 and is not available. It is attached to a support member 52 fixed to the main body (shown). As an example, the substrate 50 is fixed to the support member 52 at two locations using bolts 17B and washers 17C.

Further, as shown in FIG. 10C, as an example, the incremental scale 9SI is a pattern in which reflective portions and non-reflective portions are alternately arranged in the rotation direction (circumferential direction) of the disc 6 at a predetermined cycle, and is an absolute scale. 9SA is a pattern in which a large number of reflecting portions having a width of an integral multiple of one cycle of the incremental scale 9SI are arranged in a predetermined arrangement in the rotation direction of the disc 6. The first detection unit 11A includes a light emitting diode (hereinafter referred to as LED) 31A that irradiates the scales 9SI and 9SA with light for detection, and reference grids 53A1 and 53A2 that are 90 ° out of phase with the reflected light from the incremental scale 9SI. The light receiving element group 32E composed of the light receiving elements 32EA and 32EB that receive light through the light receiving element group 54AX consisting of the light receiving element group 54AX of the first system and the light receiving element group 54AY of the second system receiving the reflected light from the absolute scale 9SA. And have. In the light receiving element group 54AX of the first system, light receiving elements having a width a of 1/2 of the minimum line width of the reflecting portion constituting the absolute scale 9SA are arranged in the rotation direction of the disk 6 at intervals of the width a. Is. The light receiving element group 54AY of the second system has a plurality of light receiving elements having a width a arranged between and at one end of the light receiving element group 54AX of the first system.

Similarly, the second detection unit 11B is a light receiving element group 32F composed of the LED 31B and the light receiving elements 32FA and 32FB (see FIG. 11) that receive the reflected light from the incremental scale 9SI through the reference lattices whose phases are different from each other by 90 °. And a light receiving element group 54B including a group of light receiving elements of the first system and the second system for receiving the reflected light from the absolute scale 9SA.
Next, FIG. 11 shows a configuration example of the detection circuit unit 21 of the angle detection unit 4, and FIGS. 12A to 12G show a plurality of signals generated in the detection circuit unit 21 when the disk 6 is rotated. Shown. The horizontal axis of FIGS. 12A to 12G is time t, but when the disc 6 is rotating at a constant angular velocity, the horizontal axis may be regarded as the rotation angle θ of the disc 6. it can.

In FIG. 11, the detection circuit unit 21 has the same configuration as the first circuit unit 48A and the second circuit unit 48B for processing the detection signals of the first detection unit 11A and the second detection unit 11B, respectively, and the first circuit unit 48A. It also has a position output unit 80 that obtains information on the rotation angle θT (detected rotation angle) of the rotation axis SF from the rotation angles θA and θB detected by the second circuit unit 48B, respectively.
The first circuit unit 48A is an amplifier that amplifies the detection signals SA and SB (see FIG. 12A) that are output from the two light receiving elements 32EA and 32EB that receive the reflected light from the incremental scale 9SI and have different phases by 90 °. The output of the 58A and 58B, the binarization unit 60A that binarizes the outputs of the amplifiers 58A and 58B and supplies them to the absolute value processing unit 68, and the output of the amplifiers 58A and 58B are analog-to-digital converted to the interpolation processing unit 64. It has an A / D conversion unit 62 to supply. The interpolation processing unit 64 interpolates the two-phase digital signal output from the A / D conversion unit 62, and rotates within one cycle of the incremental scale 9SI with a resolution finer than 1/4 of the cycle. The angle is obtained, and the obtained rotation angle is supplied to the switching signal generation unit 66 and the synthesis processing unit 78. The rotation angle within one cycle generated by the interpolation processing unit 64 is represented by the interpolation signal Sθ having the sawtooth-shaped 360 ° in FIG. 12 (B) as one cycle. As an example, the interpolation signal Sθ becomes 0 ° when the detection signal SB is 0 °, and becomes 360 ° when the detection signal SB is 360 °.

Further, the first detection unit 11A selects either the detection signal of the light receiving element group 54AX of the first system that receives the reflected light from the absolute scale 9SA or the detection signal of the light receiving element group 54AY of the second system. A selector group 56A and a shift register 56B (bit switching unit) 56B to which a group of detection signals selected by the selector group 56A are supplied are provided. When the XY switching signal SXY (see FIG. 12C) output from the switching signal generation unit 66 is at a high level, the selector group 56A uses the detection signal ABX of the light receiving element group 54AX of the first system (see FIG. 12D). ) Is selected, and when the XY switching signal SXY is at a low level, the detection signal ABY (see FIG. 12D) of the light receiving element group 54AY of the second system is selected by the selector group 56A. In FIG. 12D, the detection signals ABX and ABY are collectively represented by the original absolute value signal ABR. When the position of the first detection unit 11A in the rotation direction is as designed, the XY switching signal SXY becomes high level in the period from 0 ° to 180 ° of the detection signal SB, and becomes low level in other periods. Become. However, in the present embodiment, the XY switching signal SXY is out of phase by the phase difference Δθ described later. That is, the XY switching signal SXY has a high level in the period from (0 ° −Δθ) to (180 ° −Δθ) of the detection signal SB, and has a low level in other periods. This action will be described later.

Further, the first detection unit 11A includes an amplifier 58C for amplifying an absolute value signal ABS (a signal obtained by connecting the detection signals ABX and ABY) output from the shift register 56B (see FIG. 12E), and an amplifier 58C. The binarization unit 60B for supplying the binarized digital signal DAB (see FIG. 12F) to the absolute value processing unit 68, the non-volatile memory 74, the control unit 76, and the position output unit 80. Have. The control unit 76 controls the light emission of the LED 31A and the like. A filter for removing noise may be installed between the binarization unit 60A and the absolute value processing unit 68, and between the binarization unit 60B and the absolute value processing unit 68, respectively. The absolute value processing unit 68 includes a processing unit 72 that obtains the absolute value of the rotation angle within one rotation (360 °) of the disk 6 from the digital signal DAB, and two-phase signals SA and SB that are binarized with the digital signal DAB. It has a phase difference measuring unit 70 for obtaining a phase difference from the rotation angle within one cycle obtained from the above.

Information on the absolute value of the rotation angle within one rotation obtained by the absolute value processing unit 68 is supplied to the synthesis processing unit 78. The compositing processing unit 78 adds the intercalated rotation angle within one cycle of the incremental scale 9SI supplied from the intercalation processing unit 64 to the absolute value of the rotation angle within one rotation, thereby causing the disk 6 ( The rotation angle θA within one rotation of the rotation axis SF) is obtained with a resolution finer than 1/4 of the one cycle, and the obtained information of the rotation angle θA is supplied to the position output unit 80.

Information on the phase difference Δθ (see FIG. 12B) between the two-phase signals SA and SB and the digital signal DAB actually measured before the operation of the encoder device ECB is written to the non-volatile memory 74 by the control unit 76, for example. ing. The information on the phase difference of the angle and the phase difference of the angular velocity obtained by the absolute value processing unit 68, and the information of the phase difference Δθ read from the non-volatile memory 74 are supplied to the switching signal generation unit 66. In the switching signal generation unit 66, the detection signal SB is high in the period from (0 ° −Δθ) to (180 ° −Δθ) as shown in FIG. 12C by using the information such as the phase difference Δθ. It generates an XY switching signal SXY that becomes a level and becomes a low level in other periods.

The configuration of the second circuit unit 48B that processes the detection signal of the second detection unit 11B is the same as that of the first circuit unit 48A. The second circuit unit 48B uses the detection signals of the light receiving elements 32FA and 32FB of the second detection unit 11B and the detection signals of the light receiving element group 54B to set the rotation angle θB within one rotation of the disk 6 (rotation axis SF). It is obtained with a resolution finer than 1/4 of one cycle of the incremental scale 9SI, and the obtained information on the rotation angle θB is supplied to the position output unit 80. As an example, the position detection unit 80 obtains the average value of the two rotation angles θA and θB as the detected rotation angle θT, and supplies the obtained rotation angle θT to the synthesis unit 23 of FIG. The operation of the motor M is controlled by using the rotation angle θT and the multi-rotation information obtained by the multi-rotation information detection unit 3 in FIG.

Next, an example of the positioning method and the detection method of the encoder device ECB of the present embodiment will be described with reference to the flowchart of FIG. 14 (A). First, in step 160 of FIG. 14A, members such as a disk 6 constituting the encoder device ECB, a support member 52, and a substrate 50 to which the detection units 11A and 11B and the detection circuit unit 21 are attached are manufactured. The disc 6 is attached to the surface of the disk 5 of the rotating shaft SF by bolts 17, and the support member 52 is fixed to a main body (not shown). Then, in step 162, as shown in FIG. 13A, the substrate 50 is attached to the support member 52 using two bolts 17B. At this time, the radial direction (R direction) of the first detection unit 11A and the position in the radial direction (R direction) of the disk 6 of the first detection unit 11A and the second detection unit 11B are aligned with the position of the pattern 9S. The position of the second detection unit 11B in the radial direction (R direction) is adjusted. As an example, the detection signals of the light receiving elements 32EA and 32EB (or the light receiving element group 54A) of the first detection unit 11A and the light receiving elements 32FA and 32FB (or the light receiving elements) of the second detection unit 11B while rotating the disk 6 in the θ direction. The detection signal of the group 54B) is monitored, and first, the position of the substrate 50 with respect to the support member 52 in the R direction is set so that the detection signals of the light receiving elements 32EA and 32EB (or the light receiving element group 54A) of the first detection unit 11A are maximized. After that, the position of the substrate 50 with respect to the support member 52 in the R direction is adjusted so that the detection signals of the light receiving elements 32FA and 32FB (or the light receiving element group 54B) of the second detection unit 11B are maximized. For these adjustments, as an example, two bolts 17B may be fixed while adjusting the position of the substrate 50 with respect to the support member 52. As a result, the reflected light from the incremental scale 9SI with respect to the light receiving elements 32EA and 32EB of the first detection unit 11A and the light receiving elements 32FA and 32FB of the second detection unit 11B is optimized, and the light receiving element group 54A of the first detection unit 11A , And the reflected light from the absolute scale 9SA with respect to the light receiving element group 54B of the second detection unit 11B is optimized. Therefore, the angle detection unit 4 can detect the rotation angle of the disk 6 with high accuracy with a high SN ratio.

In this way, it is relatively easy to adjust the positions of the first detection unit 11A in the R direction and the second detection unit 11B in the R direction while monitoring the amplitude of the detection signal. However, in this case, as shown in FIG. 13B, the positions of the first detection unit 11A and the second detection unit 11B in the θ direction may deviate from the target positions. As an example, the center of the first detection unit 11A (for example, the center of LED31A) deviates from the target position by δ1 in the θ direction, and the center of the second detection unit 11B (for example, the center of LED31B) deviates from the target position by δ2 in the θ direction. ing. The deviation of the position in the θ direction includes an error in the mounting position and mounting angle of the detection units 11A and 11B with respect to the substrate 50. As a result, in the first detection unit 11A, the phase difference between the detection signals SA and SB of FIGS. 12A and 12A and the detection signals ABX and ABY is a predetermined first angle error from the target value (for example, 0). Also in the second detection unit 11B, the phase difference between the detection signal obtained from the incremental scale 9SI and the detection signal obtained from the absolute scale 9SA is deviated from the target value by a predetermined second angle error.

Therefore, in step 164, with respect to the first detection unit 11A, the absolute value signal ABS output from the amplifier 58C and the detection in a state where the phase difference Δθ supplied from the non-volatile memory 74 to the switching signal generation unit 66 is set to 0. The phase difference Δθ (corresponding to the first angle error) with the signals SA and SB is detected, and the detected phase difference Δθ is stored in the non-volatile memory 74 via the control unit 76. Similarly, the second detection unit 11B also detects the phase difference (corresponding to the second angle error) between the detection signals of the light receiving elements 32FA and 32FB and the detection signal of the light receiving element group 54B, and determines the detected phase difference. 2 Stored in the non-volatile memory in the circuit unit 48B.

After that, the operation of the encoder device ECB is started, and in step 166, the XY switching signal SXY corrected by the phase difference Δθ is supplied to the selector group 56A from the switching signal generation unit 66 of FIG. 11 in the first detection unit 11A. The angle connecting the two ABS signals ABX and ABY is corrected, and the rotation information of the disk 6 is detected with high accuracy by using the absolute value signal ABS of the signal level that is always stable by the correction. Similarly, in the second detection unit 11B, the rotation information of the disk 6 is detected with high accuracy by using the XY switching signal SXY corrected in the second circuit unit 48B. After that, if the detection is continued in step 168, step 166 is repeated.

When the phase difference Δθ is set to 0 (comparative example) without correcting the phase difference Δθ (angle error) as in the present embodiment, the absolute value signal ABS output from the shift register 56B in FIG. 11 is used. In', as shown in FIG. 12 (G), the fluctuation of the signal level becomes large. Therefore, when the absolute value signal ABS'is binarized, the correct pattern of the absolute scale 9SA cannot be obtained, and there is a possibility that an absolute value detection error may occur.

As described above, the positioning method of the encoder device ECB of the present embodiment detects the light from the pattern 9S provided along the rotational movement direction of the rotating disk 6 (moving portion) and detects the first detection signals SA, SB. The first detection unit 11A and the first detection unit 211A are arranged at positions separated from each other by a predetermined angle along the rotational movement direction of the disk 6, detect the light from the pattern 9S, and output the second detection signal. The second detection unit 11B to be output, the detection circuit unit 21 (calculation unit) that obtains the rotation information of the disk 6 from the first detection signals SA and SB and the second detection signal thereof, and the first detection unit 11A and the second detection unit. A method for positioning an encoder device including a substrate 50 (support member) that integrally supports 11B, in which the first detection unit 11A and the second detection unit 11B are respectively positioned in the radial direction of the rotational movement of the disk 6. It includes step 162.

According to this positioning method, the first detection unit 11A and the second detection unit 11B can be easily and highly accurately positioned with respect to the disk 6 (pattern 9S).
Further, the positional deviation (angle error) in the rotational direction of the first detection unit 11A and the second detection unit 11B when positioned in the radial direction is, for example, the absolute scale 9SA in the first detection unit 11A and the second detection unit 11B. By correcting the phase of the detected signal of the reflected light (the phase of connecting the two absolute value signals ABX and ABY), it can be electrically corrected with high accuracy.
The angle between the two first detection units 11A and the second detection unit 11B in the present embodiment is 90 °, but the angle may be any angle other than, for example, 180 °.

[Third Embodiment]
The third embodiment will be described with reference to FIGS. 15 and 14 (B). In FIG. 15, the parts corresponding to FIGS. 10A to 11 are designated by the same reference numerals, and detailed description thereof will be omitted. FIG. 15 shows the mechanical unit of the angle detection unit 4A of the encoder device ECC according to the present embodiment. In FIG. 15, the disk 6 is attached to the disk 5 of the rotation axis SF of FIG. 10B, and is used for angle detection including an incremental scale 9SI and an absolute scale 9SA concentrically around the center of rotation on the surface of the disk 6. Pattern 9S is formed. The angle detection unit 4 processes the detection signals of the first detection unit 11A for detecting the light from the pattern 9S of the disk 6, the second detection unit 11B for detecting the light from the pattern 9S at different positions, and the detection units 11A and 11B. It has a detection circuit unit 21A for detecting an angle θ within one rotation of the disk 6 (rotation axis SF). The configuration of the detection circuit unit 21A is the same as that of the detection circuit unit 21 of FIG. In the present embodiment, it is assumed that the position of the second detection unit 11B is deviated from the first detection unit 11A by an angle φ (0 ° <φ <360 °) in the rotation direction (θ direction) of the disk 6. ..

A position output unit 80A is provided in the detection circuit unit 21A, and the position output unit 80A is the rotation angle of the disk 6 obtained by processing the detection signals output from the first detection unit 11A and the second detection unit 11B, respectively. θA and θB are supplied. The position output unit 80A processes the rotation angles θA and θB to obtain the rotation angle θT of the disk 6, and supplies the information on the obtained rotation angle θT to the synthesis unit 23 in FIG. The motor M of FIG. 1 is controlled by using the information of the rotation angle obtained by the synthesis unit 23 of FIG.

Next, an example of the detection method of the encoder device ECC of the present embodiment will be described with reference to the flowchart of FIG. 14 (B). First, in step 172 of FIG. 14B, the encoder device is assembled. In the next step 174, for example, while rotating the disk 6 once, the position output unit 80A processes the detection signals output from the first detection unit 11A and the second detection unit 11B, respectively, and the rotation angle of the disk 6 is obtained. Information on θA and θB is taken in at a predetermined sampling rate. Then, the position output unit 80A calculates the detection error for each nth harmonic (n is an integer of 1 or more) as follows using the information of the captured rotation angle. Assuming that the rotation angles θA and θB are the functions f (θ) and f (θ + φ), respectively, the error of the encoder device is restored by rotating the disk 6 once (360 ° rotation), so that the functions f (θ) and f (Θ + φ) can be expressed using the Fourier series as follows.

これらの式において、ｎは高調波の次数、Ａ_n はｎ次高調波の振幅、α_n はｎ次高調波の初期位相、Ｎはディスク６のインクリメンタルスケール９ＳＩの目盛数（周期の数）である。位置出力部８０Ａでは、２つの回転角の読み取り値の差分（以下、比較測定値という。）δ（θ）を求める。（１）式、（２）式を用いると、比較測定値δ（θ）は次のようになる。なお、（１）式から（３）式における角度の単位はｒａｄであるとする。

In these formulas, n represents the order of the harmonic, A _n is the n-th harmonic amplitude, alpha _n is the n-th harmonic of the initial phase, N represents a scale number of incremental scale 9SI disk 6 (the number of cycles) is there. The position output unit 80A obtains the difference between the readings of the two rotation angles (hereinafter referred to as the comparative measurement value) δ (θ). Using equations (1) and (2), the comparative measurement value δ (θ) is as follows. It is assumed that the unit of angle in the equations (1) to (3) is rad.

式（３）において、角度φ以外の部分が回転角の誤差になるため、誤差はｎ次高調波毎にその位相と振幅を予め計算によって求めることができる。
本実施形態において、２つの検出部１１Ａ，１１Ｂの角度φが９０°（π／２）である場合、（３）式においてφにπ／２を代入することで次式が得られる。

In the equation (3), since the portion other than the angle φ is the error of the rotation angle, the error can be obtained by calculating the phase and the amplitude of each nth harmonic in advance.
In the present embodiment, when the angles φ of the two detection units 11A and 11B are 90 ° (π / 2), the following equation can be obtained by substituting π / 2 for φ in the equation (3).

一方、（４）式の位相成分は、（１）式に対して（２＋ｎ）π/4だけ元の誤差に対して位相が進む。各高調波での位相シフト量は、第１高調波で（3/4）π、第２高調波でπ（逆相）、第３高調波で（5/4）π、第４高調波で（3/2）π（但し、振幅は０）、第５高調波で（７/4）π、第６高調波で２π（同相だが振幅がマイナスなので、逆相となる）、第７高調波で（9/4）π（＝π／４）、第８高調波で（５/２）π（但し、振幅は０）となる。

On the other hand, the phase component of the equation (4) advances the phase with respect to the original error by (2 + n) π / 4 with respect to the equation (1). The phase shift amount for each harmonic is (3/4) π for the first harmonic, π (opposite phase) for the second harmonic, (5/4) π for the third harmonic, and (5/4) π for the fourth harmonic. (3/2) π (however, the amplitude is 0), the 5th harmonic (7/4) π, the 6th harmonic 2π (in phase but the amplitude is negative, so the phase is opposite), the 7th harmonic (9/4) π (= π / 4), and (5/2) π (however, the amplitude is 0) at the 8th harmonic.

Since the amplitude and phase of each harmonic can be calculated in this way, if the phase shift and the amount of increase / decrease in amplitude at the order n of each harmonic are corrected for the comparative measurement value δ (θ), the detection result will be obtained. Error correction is possible. As an example, in step 176, the position output unit 80A calculates the amplitude and phase of each harmonic thereof, and stores the calculation result in a non-volatile memory (not shown) in the detection circuit unit 21A. Then, in step 178, when detecting the rotation information of the disk 6, the detection result can be corrected by using the amplitude and phase of each of the stored harmonics. If the detection is continued in the next step 180, step 178 is repeated. However, for harmonics of multiples of 4, the amplitude becomes 0, so the error cannot be manifested. For even-numbered harmonics other than multiples of 4, errors can be canceled out in real time by averaging the angle detection values of the detection units 11A and 11B. In this method of performing the Fourier transform, only one calculation is required, the calculation does not need to be repeated, and the error residuals do not accumulate, so that highly accurate correction is possible.

Further, the following processes a1) to a8) may be performed in order to correct the error of the detection result for each harmonic order without calculating the Fourier transform. This method does not require complicated calculations (only four arithmetic operations are required), and the burden on the detection circuit unit 21A side is lightened.
a1) The comparative measurement value δ (θ) (difference between the detection results of the detection units 11A and 11B) of the equation (3) is acquired for one rotation (one round) of the disk 6.
a2) Generates a waveform with an amplitude of ^{+2 1/2} times that the phase is advanced by (3/4) π with respect to the comparative measurement value δ (θ).
Data for tilt correction is generated from the waveforms generated in a3) and a2).
a4) The data generated in a3) is written in the storage unit in the detection circuit unit 21A. At this point, the first harmonic components of the error are offset. At the same time, the error is corrected because the original error matches the phase and amplitude of the harmonic component of the multiple order (x is a natural number starting from 1) of (8x ± 1). For errors other than first-order or (8x ± 1) multiple-order harmonics, the amplitude and phase will be different from the original error curve.

In the same manner as in a5) a1) to a4), the second harmonic component of the error is corrected. At this point, not only the second harmonic component of the error is canceled out, but also the harmonic component of the multiple order of (8x ± 2) has the phase and amplitude with respect to the error remaining in a4) above. Therefore, the error is corrected. The remaining error time will have a different amplitude and phase from the original error curve, but for the first-order and (8x ± 1) multiple-order harmonics, the error has already been offset, so the first-order. And the error amplitude of the harmonics of multiples of (8x ± 1) remains zero.
Similar to a6) and a5), the third harmonic component of the error is also corrected. Similarly, the third harmonic component of the error is offset. Also, for harmonic components of multiples of (8x ± 3), the error is corrected because the phase and amplitude match the error that became the residual in a4). At this point, the errors are canceled out for harmonic components other than the 4th (multiple) order.
a7) Harmonics of the 4th order and the order of multiples of 4 do not need to be corrected because the error does not become apparent.

Since this method has a light calculation load, the detection circuit unit 21A can be easily configured. In this method, the amplitude of the error component other than the order to be corrected changes, but the error amplitude is theoretically 0 for the error of the order that has already been offset, so that no problem theoretically occurs.

As described above, the position detection method of the encoder device ECC of the present embodiment detects the light from the pattern 9S provided along the rotational movement direction of the rotating disk 6 (moving portion) and detects the first detection signal SA, The first detection unit 11A that outputs SB and the first detection unit 211A are arranged at positions separated by a predetermined angle along the rotational movement direction of the disk 6, and the light from the pattern 9S is detected to detect the second detection signal. This is a position detection method for an encoder device including a second detection unit 11B for outputting the above, and a detection circuit unit 21A (calculation unit) for obtaining rotation information of the disk 6 from the first detection signals SA, SB and the second detection signal. Then, steps 174 and 176 for obtaining the error of the rotation information from the difference between the rotation information of the disk 6 obtained from the first detection signal and the rotation information of the disk 6 obtained from the second detection signal, and the first step. It includes a detection signal, a second detection signal thereof, and step 178 for obtaining rotation information of the disk 6 using the error.
According to this position detection method, the rotation information of the disk 6 (pattern 9S) can be obtained with high accuracy.

In the above-described embodiment, the position detection system 2 detects the rotation position information of the rotation axis SF (moving unit) as the movement information, but detects at least one of the position, speed, and acceleration in the predetermined direction as the movement information. You may. The encoder devices EC, ECA, ECB, and ECC may include a rotary encoder or a linear encoder. The encoder devices EC, ECA, ECB, and ECC are reflection type encoders, but may be transmission type encoders.

[Drive]
An example of the drive device will be described. FIG. 16 is a diagram showing an example of the drive device MTR. In the following description, the same or equivalent components as those in the above-described embodiment are designated by the same reference numerals to omit or simplify the description. This drive device MTR is a motor device including an electric motor. The drive device MTR includes a rotation axis SF, a main body (drive unit) BD that rotationally drives the rotation axis SF, and an encoder device EC that detects rotation position information of the rotation axis SF. The encoder devices ECA and ECB may be provided instead of the encoder device EC (the same applies hereinafter).

The rotating shaft SF has a load-side end SFa and a non-load-side end SFb. The load side end SFa is connected to another power transmission mechanism such as a speed reducer. The disk 6 is fixed to the counterload side end SFb via the fixing portion. An encoder device EC is attached corresponding to this disk 6. The encoder device EC is an encoder device according to the above-described embodiment, modification, or combination thereof.

In this drive device MTR, the motor control unit 26 shown in FIG. 1 controls the main body unit BD using the detection result of the encoder device EC. The drive device MTR can drive the rotation axis SF with high accuracy by using the rotation information of the rotation axis SF detected by using the encoder device EC. The drive device MTR is not limited to the motor device, and may be another drive device having a shaft portion that rotates using hydraulic pressure or pneumatic pressure.

[Stage device]
An example of the stage device will be described. FIG. 17 shows the stage device STG. This stage device STG has a configuration in which a rotary table (moving object) TB is attached to the load side end SFa of the rotary shaft SF of the drive device MTR shown in FIG. In the following description, the same or equivalent components as those in the above-described embodiment are designated by the same reference numerals to omit or simplify the description.

When the stage device STG drives the drive device MTR to rotate the rotation shaft SF, this rotation is transmitted to the rotary table TB. At that time, the encoder device EC detects the angular position of the rotation axis SF and the like. Therefore, the angular position of the rotary table TB can be detected by using the output from the encoder device EC. A speed reducer or the like may be arranged between the load side end SFa of the drive device MTR and the rotary table TB.

Since the stage device STG can drive the rotary shaft SF with high accuracy by using the encoder device EC, the rotary table TB can be controlled with high accuracy. The stage device STG can be applied to, for example, a rotary table provided in a machine tool such as a lathe.
[Robot device]
An example of a robot device will be described. FIG. 18 is a perspective view showing the robot device RBT. Note that FIG. 18 schematically shows a part (joint portion) of the robot device RBT. In the following description, the same or equivalent components as those in the above-described embodiment are designated by the same reference numerals to omit or simplify the description. This robot device RBT has a first arm AR1, a second arm AR2, and a joint portion JT. The first arm AR1 is connected to the second arm AR2 via the joint JT.

The first arm AR1 includes an arm portion 91, a bearing 91a, and a bearing 91b. The second arm AR2 has an arm portion 92 and a connecting portion 92a. The connecting portion 92a is arranged between the bearing 91a and the bearing 91b in the joint portion JT. The connecting portion 92a is provided integrally with the rotating shaft SF2. The rotary shaft SF2 is inserted into both the bearing 91a and the bearing 91b at the joint portion JT. The end of the rotating shaft SF2 on the side inserted into the bearing 91b penetrates the bearing 91b and is connected to the speed reducer RG.

The speed reducer RG is connected to the drive device MTR, and reduces the rotation of the drive device MTR to, for example, 1/100 or the like and transmits it to the rotation shaft SF2. Although not shown in FIG. 18, the load side end SFa of the rotation shaft SF of the drive device MTR is connected to the speed reducer RG. Further, a disk 6 of the encoder device EC is attached to the counterload side end SFb of the rotating shaft SF of the drive device MTR.

When the robot device RBT drives the drive device MTR to rotate the rotation shaft SF, this rotation is transmitted to the rotation shaft SF2 via the speed reducer RG. The rotation of the rotation shaft SF2 causes the connection portion 92a to rotate integrally, whereby the second arm AR2 rotates with respect to the first arm AR1. At that time, the encoder device EC detects the angular position of the rotation axis SF and the like. Therefore, the angular position of the second arm AR2 can be detected by the output from the encoder device EC.

The robot device RBT can perform positioning with high accuracy by using the encoder device EC. The robot device RBT is not limited to the above configuration, and the drive device MTR can be applied to various robot devices having joints.

2 ... Position detection system, 3 ... Multi-rotation information detection unit, 4 ... Angle detection unit, 6 ... Disc, 8A to 8D ... Half-ring band pattern, 10A ... First detection unit, 10B ... Second detection unit, 11A ... 1st detection unit, 11B ... 2nd detection unit, 13 ... control unit, 14 ... storage unit, 15 ... battery, 22 ... signal synthesis unit, 26 ... motor control unit, 31,34 ... LED, 32A to 32E, 35A to 35E ... light receiving element, 33A, 33B, 36A, 36B ... analog comparator, 39 ... light emission control unit, 40 ... arithmetic control unit, EC, ECA, ECB, ECC ... encoder device, SF ... rotary axis, M ... motor, AR1 ... 1st arm, AR2 ... 2nd arm, MTR ... drive device, RBT ... robot device, STG ... stage device

Claims (22)

A first detection unit that irradiates a pattern of the moving unit with light, detects light from the pattern, and outputs a first detection signal and a second detection signal having different phases with respect to the movement of the moving unit.
A second detection that is arranged at different positions along the moving direction of the moving unit with respect to the first detecting unit, irradiates the pattern with light, detects the light from the pattern, and outputs a third detection signal. Department and
The movement information of the moving unit is obtained from the first detection signal and the second detection signal, and the movement information is obtained from one of the first detection signal, the second detection signal, and the third detection signal. A control unit that switches between states and
An encoder device including a calculation unit that obtains movement information from a detection signal in a state of being switched by the control unit. The encoder device according to claim 1, wherein the second detection unit outputs the third detection signal having the same phase as one of the first detection signal and the second detection signal with respect to the movement of the moving unit. The pattern includes a plurality of partial patterns arranged at different positions of the moving portion with respect to the moving direction of the moving portion.
The encoder device according to claim 1 or 2, wherein the first detection unit and the second detection unit are arranged with respect to the moving unit in a positional relationship corresponding to the positional relationship of the pattern. The moving part rotates around the axis of rotation,
The first detection signal and the second detection signal have different phases depending on the positional relationship.
The encoder device according to any one of claims 1 to 3, wherein the calculation unit detects multi-rotation information of the rotation axis by the first detection signal and the second detection signal. The pattern includes a first pattern and a second pattern arranged at different positions along the moving direction of the moving portion.
The two detection signals having different phases are the first detection signal generated by the first detection unit detecting the light from the first pattern and the second detection unit from the first pattern. The encoder device according to any one of claims 1 to 4, which includes the third detection signal generated by detecting light. The calculation unit
Claims 1 to 5 for obtaining the movement information of the moving unit by changing one of the first detection signal and the second detection signal to the third detection signal by the first detection signal and the second detection signal. The encoder device according to any one of the above. The encoder device according to claim 6, wherein the calculation unit uses the third detection signal to obtain the movement information by combining the state of the detection signal of the first detection unit and the detection signal of the second detection unit. The encoder device according to claim 6, wherein the calculation unit uses the third detection signal to obtain the movement information based on a state transition between the detection signal of the first detection unit and the detection signal of the second detection unit. The encoder device according to any one of claims 1 to 8, and the encoder device.
A power supply unit that supplies power to the moving unit and
A drive device equipped with. With moving objects
A stage device including the drive device according to claim 9, which moves the moving object. The drive device according to claim 9 and
A robot device including an arm that moves relative to each other by the drive device. A first detection unit that irradiates a pattern of the moving unit with light, detects light from the pattern, and outputs a first detection signal and a second detection signal having different phases with respect to the movement of the moving unit.
A second detection that is arranged at different positions along the moving direction of the moving unit with respect to the first detecting unit, irradiates the pattern with light, detects the light from the pattern, and outputs a third detection signal. Department and
It includes a calculation unit that obtains movement information of the moving unit by two detection signals having different phases with respect to the movement of the moving unit among the first detection signal, the second detection signal, and the third detection signal. How to use the encoder device
The movement information is obtained from a state in which the position information of the moving portion is obtained from the first detection signal and the second detection signal, and one of the first detection signal, the second detection signal, and the third detection signal. Switch between states,
A method of using an encoder device, which comprises obtaining movement information of the moving portion from a detection signal in a switched state. The method of using the encoder device according to claim 12, wherein the movement information is obtained by using the third detection signal by combining the states of the first detection signal and the second detection signal. The method of using the encoder device according to claim 12, wherein the movement information is obtained by using the third detection signal by the state transition between the first detection signal and the second detection signal. A first detection unit that detects light from a pattern provided along the movement direction of the rotating movement unit and outputs a first detection signal, and a first detection unit.
A second detection unit, which is arranged at a position separated from the first detection unit by a predetermined angle along the moving direction of the moving unit, detects light from the pattern, and outputs a second detection signal.
A calculation unit that obtains rotation information of the moving unit from the first detection signal and the second detection signal, and
A method for positioning an encoder device including a support member that integrally supports the first detection unit and the second detection unit.
Positioning the first detection unit and the second detection unit in the radial direction of the rotational movement of the moving unit, respectively.
How to position an encoder device, including. The method for positioning an encoder device according to claim 15, wherein the predetermined angle is 90 °. A method for detecting the position of an encoder device positioned by the positioning method according to claim 15 or 16.
The first detection signal and the second detection signal include an incremental signal and an absolute signal, respectively.
The calculation unit further includes correcting the phase of the absolute signal with reference to the incremental signal of the first detection signal, and correcting the phase of the absolute signal with reference to the incremental signal of the second detection signal. How to detect the position of the encoder device. The incremental signal includes a two-phase signal having a phase difference of 90 °, the absolute signal includes two signals, and correcting the phase of the absolute signal connects the two signals of the absolute signal. The position detection method for an encoder device according to claim 17, which comprises correcting an angle. A first detection unit that detects light from a pattern provided along the movement direction of the rotating moving unit and outputs a first detection signal regarding the rotational movement of the moving unit.
A second detection unit, which is arranged at a position separated from the first detection unit by a predetermined angle along the moving direction of the moving unit, detects light from the pattern, and outputs a second detection signal.
A method for detecting the position of an encoder device including a calculation unit that obtains rotation information of the moving unit by the first detection signal and the second detection signal.
Obtaining the error of the rotation information from the difference between the rotation information of the moving portion obtained from the first detection signal and the rotation information of the moving portion obtained from the second detection signal.
A method for detecting the position of an encoder device, which comprises obtaining rotation information of the moving portion using the first detection signal, the second detection signal, and the error. The position detection method for an encoder device according to claim 19, wherein obtaining the error includes obtaining an error for each order of a fundamental wave and a harmonic having 360 ° as one cycle of the rotation angle of the moving portion. The position detection method for an encoder device according to claim 19 or 20, wherein the first detection signal and the second detection signal include an incremental signal and an absolute signal, respectively. The position detection method for an encoder device according to any one of claims 19 to 21, wherein the predetermined angle is 90 °.

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