Encoder manufacturing method

Abstract

To provide an actuator using an encoder which can align a moving position of a motor and the actually measured result of detection of an encoder with each other.SOLUTION: An actuator includes a motor and an encoder with an encoder mirror 344a. An encoder mirror 344a moves in association with the motor. The encoder mirror 344a is marked with a plurality of scales Sk in a moving direction to determine the moving position of the motor. The scales Sk are located in positions for marking a predetermined moving position of the motor when the motor is activated.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present invention relates to workman a method for manufacturing an encoder. More specifically, it relates to a method for manufacturing an encoder of used to obtain the moving position of a motor.

Background Art

[0002] In order to operate the arm of a robot or the like, an actuator may be used. For example, a rotary electric motor is incorporated in this actuator, and the position of the arm is controlled by controlling the mechanical angle of the rotary electric motor. At this time, an encoder may be used to detect the moving position of the rotary electric motor. In the case of a rotary electric motor, for example, a scale is marked in the circumferential direction of a disk-shaped encoder mirror. Then, by reading this scale, the mechanical angle is detected as the moving position of the rotary electric motor.

[0003] Patent Document No. 1 discloses a method for manufacturing a rotary scale attached to the rotation axis of a rotating body. This method for manufacturing a rotary scale has a first step, a second step, and a third step. The first step is to form a scale pattern and a mark on a scale base material. The mark indicates the outer shape of the rotation axis when the central axis of the rotation axis is aligned with the central axis of the scale pattern. The second step is to cut a first region of the scale base material having a first width and including the mark. The third step is to cut a second region having a second width. The second width includes the mark remaining after cutting the first region, and the circumferential length of the scale base material is shorter than that of the first region and smaller than the first width.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

[0005] However, due to factors such as mechanical errors, there may be a discrepancy between the actual measured position of the motor and the detection result of the encoder. In such cases, the accuracy of detecting the motor's position decreases. This invention provides an encoder that is less prone to discrepancies in the detection results of the encoder relative to the motor's movement position. Manufacturing method The purpose is to provide. [Means for solving the problem]

[0008] Book The invention relates to a method for manufacturing an encoder, which includes an encoder scale. The encoder moves in conjunction with a motor to determine the motor's position. The encoder includes an encoder scale with multiple scales marked in the direction of movement. The method for manufacturing the encoder includes a marking step. In the marking step, when the motor is operated, the scale is marked in accordance with a predetermined position of the motor.

[0009] Here, the motor can be a brushless motor. In this case, the marking process includes a first marking process. The first marking process involves energizing the coil that operates the brushless motor in a predetermined energizing mode. Then, the first scale is marked at the location where the encoder scale rotates during this process. Furthermore, the first marking step may involve applying power multiple times for a single energizing mode. This allows for positioning of the location where the first scale will be marked. Furthermore, the first marking step may involve energizing the motor in both forward and reverse directions for a single energizing mode. This allows for positioning of the area to be marked. Furthermore, the process may include a second marking step, in which a second scale is marked in addition to the first scale marked in the first marking step.。 Furthermore, the process may include a mounting step in which a motor equipped with an encoder scale is placed on a table. The table is capable of moving horizontally and rotationally relative to the encoder scale. The second marking step then moves the table according to the position of the first scale. This moves the encoder scale horizontally and rotationally, and marks the second scale. Furthermore, a Hall sensor may be used in conjunction with the scale marking to determine the location of the markings. This is applied to at least one of the first marking step and the second marking step. The Hall sensor is attached to the brushless motor. Furthermore, a load may be applied to the rotation mechanism of the encoder scale to prevent backslash from occurring. This is applied to at least one of the first marking step and the second marking step. Furthermore, the motor can be a rotary electric motor. In this case, the rotational position of the rotary electric motor is controlled by a pre-reduction encoder. The pre-reduction encoder is an encoder attached to the rotary electric motor before reduction. In this case, the marking process involves marking a scale. The scale is marked at the position where the reduced-reduction encoder scale has rotated, corresponding to the rotational position of the rotary electric motor. 。 [Effects of the Invention]

[0010] According to the present invention, even if a misalignment of the central axis occurs between the encoder before and after deceleration, an encoder that is less prone to angular errors is obtained. Manufacturing method We can provide this. [Brief explanation of the drawing]

[0011] [Figure 1] This figure shows an example of the overall configuration of a robot system to which this embodiment is applied. [Figure 2] (a) is a perspective view of the actuator. (b) is a cross-sectional view of the actuator shown in (a). [Figure 3](a) is a diagram showing the configuration of a motor. (b) is a diagram showing an example of the connection of a plurality of coils Co. [Figure 4] (a) to (b) are diagrams showing an encoder mirror. [Figure 5] It is a block diagram showing an example of the functional configuration of a control unit when controlling an actuator. [Figure 6] It is a flowchart showing a scale marking method in the first embodiment. [Figure 7] (a) is a diagram showing the energization mode of step 102 in FIG. 6. (b) is a diagram showing the direction of the magnetic flux generated in the motor. (c) is a diagram showing the first scale marked on the encoder mirror. [Figure 8] (a) to (f) are diagrams showing the relationship between the number of pole pairs and the range for marking the first scale. [Figure 9] (a) to (k) are diagrams showing specific operation examples of steps 105 to 106 in FIG. 6. [Figure 10] (a) to (b) are diagrams showing the relationship between the first scale and the second scale marked in the first embodiment. [Figure 11] It is a block diagram showing the functional configuration of a control unit for controlling a motor and a table in the first embodiment. [Figure 12] It is a flowchart showing a scale marking method in the second embodiment. [Figure 13] (a) to (g) are diagrams showing specific operation examples of steps 202 to 205 in FIG. 12. [Figure 14] It is a flowchart showing a scale marking method in the third embodiment. [Figure 15] (a) to (f) are diagrams showing specific operation examples of steps 302 to 303 in FIG. 14. [Figure 16](a) is a diagram showing the energization mode of a two-phase brushless motor. (b) is a diagram showing the first scale marked at this time. [Figure 17] (a) to (b) are diagrams showing the detection results of a conventional encoder. [Figure 18] (a) is a conceptual diagram showing the misalignment of the central axes of the encoder before deceleration and the encoder after deceleration by a speed reducer. (b) is a diagram showing the angular error that occurs between the encoder before deceleration and the encoder after deceleration when the misalignment of the central axis occurs. [Figure 19] (a) is a diagram showing a linear motor. (b) is a diagram showing the state of sequentially marking a scale.

Embodiments for Carrying out the Invention

[0012] Hereinafter, embodiments for carrying out the present invention will be described in detail. Note that the present invention is not limited to the following embodiments. Further, various modifications can be made within the scope of the gist. Furthermore, the drawings used are for explaining the present embodiment and do not represent the actual size.

[0013] <Explanation of the Overall Configuration of the Robot System 1> Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 is a diagram showing an example of the overall configuration of a robot system 1 to which the present embodiment is applied. The illustrated robot system 1 includes a photographing device 10, an image processing device 20, and a robot 30. Although not constituting the robot system 1, the state where a plurality of parts B are contained in a box is also illustrated here.

[0014] The photographing device 10 photographs an image of the part B. The photographing device 10, for example, photographs the inside of a box in which a plurality of parts B are stacked from above and creates a photographed image. The image processing device 20 determines the position and orientation of part B based on the image captured by the imaging device 10. The robot 30 grasps part B. The robot 30 comprises a hand 31 that actually grasps part B and an arm 32 that positions the hand 31. The robot 30 also comprises a robot control unit 33 that controls the movement of the hand 31 and the arm 32. Furthermore, the robot 30 comprises an actuator 34 that rotates under the control of the robot control unit 33.

[0015] The robot system 1 described above operates as follows: First, the imaging device 10 captures an image of part B. This image is acquired by the image processing device 20. The image processing device 20 then determines the position and orientation of part B based on this image. Furthermore, the position and orientation of part B determined by the image processing device 20 are sent to the robot control unit 33 of the robot 30. Based on the position and orientation of part B, the robot control unit 33 controls the hand 31 and arm 32 to grasp part B. The robot 30 is rotatable in the direction of the double arrows in the actuator 34 shown in the figure. By rotating the actuator 34, the hand 31 and arm 32 can be moved to a position for grasping part B. After part B is grasped, for example, the robot 30 can arrange part B in a predetermined position. Alternatively, for example, the robot 30 can assemble part B in order to assemble a product.

[0016] The robot 30 was intended to grasp and assemble part B, but is not limited to this. For example, robot 30 may be a welding robot that performs welding. Also, for example, robot 30 may be a transport robot that performs transport or a painting robot that performs painting. Furthermore, robot system 1 does not have to include the imaging device 10 or the image processing device 20. In this case, robot 30 repeats predetermined operations in a predetermined sequence. Also, robot system 1 may have the imaging device 10 or the image processing device 20 inside the robot. For example, robot system 1 may have the imaging device 10 or the image processing device 20 at the tip of arm 32 (the position of hand 31), etc. Furthermore, the robot 30 may be not only a fixed type that is fixed in a predetermined location, but also a mobile type that can be moved.

[0017] <Description of Actuator 34> Figure 2(a) is a perspective view of the actuator 34. Figure 2(b) is a cross-sectional view of the actuator 34 shown in Figure 2(a). As shown in Figures 2(a) and 2(b), the actuator 34 comprises a motor 341, a reduction gear 342, a rotating shaft 343, and an encoder 344.

[0018] Figure 3(a) shows the configuration of the motor 341. Motor 341 is a rotary electric motor, and more specifically, a brushless motor. Motor 341 comprises a rotor 341a and a stator 341b. As shown in the figure, the rotor 341a is housed inside the stator 341b. That is, the motor 341 shown in the figure is a so-called inner rotor type brushless motor. The rotor 341a rotates when power is supplied to the stator 341b. The rotor 341a comprises a rotating shaft and a main magnet mounted on the rotating shaft. A cylindrical magnet with two poles can be exemplified as the main magnet. The stator 341b is arranged around the rotor 341a and consists of multiple coils Co that form a cylindrical shape overall. The ends of these coils Co are connected in predetermined combinations.

[0019] Figure 3(b) shows an example of the connection of multiple coils Co. Here, we show the case where six coils Co1 to Co6 are connected as coil Co. Co1 to Co6 are connected as shown in Figure 3(b). Specifically, coil Co3 and coil Co6 are connected in series. Coil Co5 and coil Co2 are connected in series. Furthermore, coil Co1 and coil Co4 are connected in series. The phase formed by coil Co3 and coil Co6 is designated as the V phase. Furthermore, the phase formed by coil Co5 and coil Co2 is designated as the U phase. Furthermore, the phase formed by coil Co1 and coil Co4 is designated as the W phase. In this case, one end of coil Co6 is the V phase terminal, one end of coil Co2 is the U phase terminal, and one end of coil Co4 is the W phase terminal. Then, one end each of coil Co1, Co3, and Co5 are connected to each other, forming the neutral point (neutral terminal) N. As a result, coils Co1 to Co6 become a three-phase star-connected coil. This connection is also called a star connection. With this wiring, motor 341 operates as a three-phase brushless motor. While a star connection has been described here, it is not the only option; a delta connection may also be used.

[0020] The reduction gear 342 is a device that reduces the rotational speed of the power output from the rotor 341a of the motor 341. The reduction gear 342 is composed of gears and the like. The rotational speed is reduced by the reduction gear 342 according to a predetermined reduction ratio. The rotating shaft 343 rotates due to the power output from the reduction gear 342. This then moves the arm 32 of the robot 30 shown in Figure 1.

[0021] The encoder 344 is a device for determining the movement position of the motor 341. In this case, since the motor 341 rotates, the movement position is the rotational position. That is, this encoder 344 is a rotary encoder that can detect the amount of movement (rotation) and angle (mechanical angle) of the rotation of the motor 341. The encoder 344 comprises an encoder mirror 344a and an encoder sensor 344b.

[0022] Figures 4(a) and 4(b) show the encoder mirror 344a. Figure 4(a) is an overall view of the encoder mirror 344a. Figure 4(b) is a magnified view of a part of the encoder mirror 344a. The encoder mirror 344a is an example of an encoder scale. As shown in Figure 4(a), the encoder mirror 344a is annular in shape. The encoder mirror 344a rotates in conjunction with the motor 341. In addition, as shown in Figure 4(b), the encoder mirror 344a has multiple scales Sk marked on it. The scales Sk are provided along the direction of movement of the encoder mirror 344a. In this case, the encoder mirror 344a rotates in conjunction with the rotation of the motor 341. Therefore, the scales Sk are provided in the direction of rotation (circumferential direction) of the encoder mirror 344a. The scale Sk is printed on the encoder mirror 344a, for example. Alternatively, the scale Sk can be created by laser marking or etching, for example. In this case, the encoder 344 is optical, reading the scale Sk optically. However, the encoder 344 is not limited to optical; it can also be magnetic. In this case, the scale Sk is created by magnetization.

[0023] The encoder sensor 344b reads the scale Sk of the encoder mirror 344a and counts the scale Sk. The encoder sensor 344b has a light-emitting part that illuminates the encoder mirror 344a with light. The light-emitting part is, for example, an LED (Light Emitting Diode). The encoder sensor 344b also has a light-receiving part that receives the reflected light reflected from the encoder mirror 344a. The light-receiving part is, for example, a photosensor. The reflected light shows differences in brightness between areas where the scale Sk is applied and areas where it is not. The encoder sensor 344b detects the brightness of the reflected light and converts it into an electrical signal. Furthermore, an encoder sensor board (not shown) counts the scale Sk based on this electrical signal. After the motor 341 is started, the encoder sensor board first detects the origin position of the encoder mirror 344a. Then, the encoder sensor board counts the scale Sk with the origin position as 0. This allows the mechanical angle of the motor 341 to be determined, and also allows the detection of absolute and relative positions. Therefore, it becomes possible to control the rotation of the motor 341 to a specified position, and thus control the actuator 34.

[0024] Furthermore, the encoder sensor 344b can also detect speed by detecting the count at regular time intervals. In addition, by marking two different scales Sk that are 1 / 4 phase apart and reading these, the direction of rotation can be determined. In this embodiment, the mechanical angle of the motor 341 is detected in two ways: before and after deceleration by the reduction gear 342. That is, two encoders 344 are provided, one for before deceleration by the reduction gear 342 and one for after deceleration. When using two encoders 344, one for before deceleration and one for after deceleration, both encoders 344 can be used in a manner that uses absolute position. Alternatively, the encoder 344 after deceleration can be used for position detection, and the encoder 344 before deceleration can be used for speed detection. In that case, the detection of the origin position immediately after startup, as described above, can be omitted for the encoder 344 before deceleration.

[0025] Furthermore, the actuator 34 may also be equipped with a Hall sensor. The Hall sensor is a magnetic sensor. The magnetic sensor is, for example, a Hall IC having a Hall element whose electrical characteristics (resistance) change due to the action of a magnetic field. By providing a Hall sensor, the detection accuracy of the mechanical angle of the motor 341 is further improved.

[0026] <Control mechanism of actuator 34> Figure 5 is a block diagram showing an example of the functional configuration of the robot control unit 33 and the actuator 34 when controlling the actuator 34. The robot control unit 33 issues commands to the actuator control unit 346, which controls the actuators 34, so that the tip of the hand 31 is in a predetermined position. Here, we are showing the case where there are three actuators 34. The robot control unit 33 determines the rotational position (mechanical angle) of each actuator 34 so that the tip of the hand 31 is in a predetermined position. Then, it issues commands to the actuator control unit 346 of each actuator 34 to achieve the determined rotational position (mechanical angle). The actuator control unit 346 is provided for each actuator 34 and controls the actuator 34. In this case, it controls the motor 341 to a commanded rotation position. The encoder 344 described above is used in this process. Specifically, the encoder sensor board 345 determines the count of the scale Sk based on the electrical signal detected by the encoder sensor 344b of the encoder 344. The encoder sensor board 345 then sends the count to the actuator control unit 346. The actuator control unit 346 determines and controls the rotation position of the motor 341 based on this count.

[0027] <How to mark the scale Sk> Next, we will explain how to mark the scale Sk. Here, we will describe the method of marking the scale Sk using the first to fourth embodiments.

[0028] [First Embodiment] In the first embodiment, a first marking step marks multiple scales Sk (first scale Sk1). At this time, the marking is performed with the energized state of the star connection described in Figure 3(b) set to a predetermined energized mode. Then, in the second marking step, further scales Sk (second scale Sk2) are marked between these first scales Sk1. The first embodiment can be applied to encoders 344 used before and after deceleration of the reducer 342. However, the following description will focus on the case where scales Sk are marked on encoders 344 used before deceleration.

[0029] Figure 6 is a flowchart illustrating the method for marking the scale Sk in the first embodiment.

[0030] First, the motor 341 is placed on the table (Step 101: Placement process). The motor 341 is pre-equipped with an encoder mirror 344a. That is, the encoder mirror 344a is already attached to the motor 341. Then, in this state, the motor 341 is placed on the table. This table allows the motor 341 to be moved in the horizontal and rotational directions relative to the encoder mirror 344a. Next, the power supply state of the star connection is set to a predetermined power supply mode (step 102). Then, mark the first scale, Sk1 (step 103).

[0031] Figure 7(a) shows the energization modes for step 102 in Figure 6. Figure 7(b) shows the direction of the magnetic flux generated in the motor 341 at this time. Here, it is shown that there are six possible energization modes and magnetic flux directions, from (1) to (6). Furthermore, Figure 7(c) shows the first scale Sk1 that is marked on the encoder mirror 344a at this time.

[0032] In case (1), as shown in Figure 7(a), current is supplied from the V-phase terminal through the neutral point N to the U-phase terminal. As a result, the composite magnetic flux is directed in the direction shown in Figure 7(b). Then, the rotor 341a of the motor 341 rotates in response to this change in composite magnetic flux. Furthermore, the encoder mirror 344a rotates in conjunction with this. Then, as shown in Figure 7(c), the scale Sk1 is marked at the position where the encoder mirror 344a has rotated.

[0033] In case (2), as shown in Figure 7(a), current is supplied from the V-phase terminal through the neutral point N to the W-phase terminal. As a result, the combined magnetic flux is directed in the direction shown in Figure 7(b). Then, the rotor 341a of the motor 341 rotates in accordance with this change in combined magnetic flux. The encoder mirror 344a also rotates in conjunction with this. Then, as shown in Figure 7(c), the scale Sk1 is marked at the position where the encoder mirror 344a has rotated.

[0034] Subsequently, in case (3), current is supplied from the U-phase terminal through the neutral point N to the W-phase terminal. Also, in case (4), current is supplied from the U-phase terminal through the neutral point N to the V-phase terminal. Furthermore, in case (5), current is supplied from the W-phase terminal through the neutral point N to the V-phase terminal. And in case (6), current is supplied from the W-phase terminal through the neutral point N to the U-phase terminal.

[0035] As a result, the combined magnetic flux is directed in the directions shown in Figure 7(b). In response, the rotor 341a of the motor 341 rotates. Furthermore, the encoder mirror 344a rotates in conjunction with this. Then, as shown in Figure 7(c), the scale Sk1 is marked at the position where the encoder mirror 344a has rotated. Alternatively, this can be described as setting the motor 341 to a predetermined electrical angle by energizing it in a predetermined energizing mode, and then marking the first scale Sk1 at the position where the encoder mirror 344a has rotated.

[0036] When power is applied sequentially in the power supply modes described in (1) to (6) above, the electrical angle rotates once. Also, as shown in (6), when the electrical angle rotates once, the encoder mirror 344a rotates by the equivalent of six units of the first scale Sk1. This can be considered as a movement of 360° (one rotation) of the electrical angle. Steps (1) to (6) above are repeated until the motor completes one rotation (360° of mechanical angle). The number of repetitions is determined by the number of pole pairs of the motor 341 (= electrical angle / mechanical angle). If the number of pole pairs is 4, repeating steps (1) to (6) above four times will cause the rotor 341a to rotate once. In the case of Figure 7(c), the number of pole pairs is 4, and the movement of 360° (one rotation) of the electrical angle is equivalent to 1 / 4 of a rotation of the rotor 341a. This can also be said to be a 90° rotation of the mechanical angle. Then, by repeating steps (1) to (6) above four times, the rotor 341a completes one rotation (mechanical angle 360°). Consequently, the encoder mirror 344a also completes one rotation, and the marking of the first scale Sk1 is completed.

[0037] Figures 8(a) to 8(f) show the relationship between the polar logarithm and the range for marking the first scale, Sk1. Figures 8(a) and 8(b) show the case where the number of poles is 3. In the motor 341 shown in Figure 8(b), the rotor 341a is housed inside the stator 341b. That is, the motor 341 is an inner rotor type brushless motor. The rotor 341a has magnets arranged as the main magnets so that there are 3 sets of N and S. In this case, the number of poles is 3. For an electrical angle of 360° (1 rotation), the rotor 341a rotates 1 / 3 of a turn. This can also be said to be a rotation of 120° in mechanical angle. In other words, by rotating the electrical angle 3 times, the rotor 341a rotates once (mechanical angle 360°). This can also be said to be a rotation of the motor 341 once. And along with this, the encoder mirror 344a also rotates once.

[0038] Furthermore, Figures 8(c) to 8(d) show the case where the number of poles is 4. This is the same as the case shown in Figure 7. In the motor 341 shown in Figure 8(d), the rotor 341a is arranged on the outer circumference side of the stator 341b. That is, the motor 341 is an outer rotor type brushless motor. The rotor 341a has magnets arranged as main magnets so that there are 4 sets of N and S. In this case, the number of poles is 4. As described above, for an electrical angle of 360° (1 rotation), the rotor 341a rotates 1 / 4 of a turn. This can also be said to be a 90° rotation of the mechanical angle. In other words, by rotating the electrical angle 4 times, the rotor 341a rotates 1 full rotation (mechanical angle 360°). This can also be said to be a 1 full rotation of the motor 341. And accordingly, the encoder mirror 344a also rotates 1 full rotation.

[0039] Furthermore, Figures 8(e) to 8(f) show the case where the number of poles is 7. In the motor 341 shown in Figure 8(d), the rotor 341a is positioned on the outer circumference of the stator 341b. That is, the motor 341 is an outer rotor type brushless motor. The rotor 341a is equipped with magnets as the main magnets, with 7 sets of N and S magnets. In this case, the number of poles is 7. For every 360° electrical angle (1 rotation), the rotor 341a rotates 1 / 7 of a rotation. This can also be said to be a 360° / 7 rotation of the mechanical angle. In other words, by rotating the electrical angle by 7, the rotor 341a rotates 1 full rotation (mechanical angle 360°). This can also be said to be a 1 full rotation of the motor 341. Consequently, the encoder mirror 344a also rotates 1 full rotation.

[0040] Returning to Figure 6, we determine whether the motor 341 has completed one rotation (step 104). That is, we determine whether the energizing modes (1) to (6) have been performed the same number of times as the number of pole pairs. As a result, if motor 341 has not completed one rotation (No in step 104), return to step 102. Conversely, if motor 341 completes one rotation (Yes in step 104), the process proceeds to step 105. Steps 102 to 104 can be considered as the first marking process, in which the first scale Sk1 is marked. In the first marking process, the coil Co that operates motor 341 is energized in a predetermined energizing mode. At this time, the first scale Sk1 is marked at the location where the encoder mirror 344a rotates.

[0041] The first marking step may involve energizing multiple times for a single energizing mode. That is, for example, in case (1), the process of energizing from the V-phase terminal through the neutral point N to the U-phase terminal is repeated multiple times. Then, the location for marking the first scale Sk1 is positioned. This improves the accuracy of the positioning. Furthermore, the first marking step may involve energizing the motor 341 in both forward and reverse directions for one energizing mode. Then, the location to be marked with the first scale Sk1 is positioned. This further improves the accuracy of the positioning.

[0042] In step 105, the motor 341 is moved horizontally and rotationally by moving the table according to the position of the first scale Sk1 (step 105). In other words, by moving the table, the encoder mirror 344a is moved to a predetermined position, aligning with the position of the first scale Sk1 that has already been marked. Then, mark the second scale, Sk2 (step 106).

[0043] Furthermore, it is determined whether or not the motor 341 has completed one rotation (step 107). As a result, if motor 341 has not completed one rotation (No in step 107), return to step 105. Conversely, if motor 341 completes one rotation (Yes in step 107), the series of processes is terminated.

[0044] Figures 9(a) to 9(k) illustrate specific examples of the operations in steps 105 to 106 of Figure 6. Note that in Figures 9(a) to 9(k), the first scale Sk1 is omitted to make the marking of the second scale Sk2 easier to understand. Figure 9(a) shows the state of the encoder mirror 344a before step 105. As shown in the figure, the motor 341 is mounted on the table 100. The motor 341 is pre-equipped with the encoder mirror 344a. The table 100 is movable in the x and y directions, which are the horizontal directions of the encoder mirror 344a. The table 100 is also rotatable in the θ direction about the central axis C. When marking the encoder mirror 344a used for the encoder before reduction, the reduction gear 342 is not included. Conversely, when marking the encoder mirror 344a used for the encoder after reduction, the reduction gear 342 is placed between the motor 341 and the table 100. Alternatively, a rotation mechanism may be provided on the table 100 to rotate it about the central axis C. In this case, it is preferable to use an appropriate coupling mechanism to absorb the positional displacement in the x and y directions.

[0045] Next, as shown in Figure 9(b), the encoder mirror 344a placed on the table 100 is photographed by the camera 110. Figure 9(f) is the camera image taken by the camera 110 at this time. Here, the actual image taken by the camera 110 and the target image to which this actual image is to be aligned are displayed. Then, as shown in Figure 9(c), the table 100 is moved in the x, y, and θ directions to align the actual image with the target image. Figure 9(g) is the image taken at this time, showing the process of aligning the actual image with the target image. Then, as shown in Figure 9(h), the actual image aligns with the target image, and the two overlap. Figures 9(b) to (c) and (f) to (h) correspond to step 105.

[0046] Then, as shown in Figure 9(d), the second scale Sk2 is marked using the printer 120. Figure 9(i) is the image taken at this time, showing the image with the second scale Sk2 marked.

[0047] Furthermore, Figures 9(e) and (j) show that a second secondary scale Sk2 has been marked. Additionally, Figure 9(k) shows that a third secondary scale Sk2 has been marked. Figures 9(d)-(e) and (i)-(k) correspond to step 106.

[0048] Figures 10(a) and 10(b) show the relationship between the first scale Sk1 and the second scale Sk2 to be marked in the first embodiment. In the first embodiment, the second scale Sk2 is marked between a pair of first scales Sk1 that were marked in the first marking step. Figure 10(a) shows the case where one second scale Sk2 is marked between a pair of first scales Sk1. In this case, the second scale Sk2 is marked at a location midway between the pair of first scales Sk1. Alternatively, multiple second scales Sk2 may be marked between a pair of first scales Sk1. Figure 10(b) shows the case where two second scales Sk2 are marked between a pair of first scales Sk1. In this case, the second scales Sk2 are marked at locations that divide the space between the pair of first scales Sk1 into three equal parts. That is, if N second scales Sk2 are to be provided between a pair of first scales Sk1, the angular positions obtained by dividing the space into N+1 equal parts are determined. Then, the second scales Sk2 are marked at each of these angular positions.

[0049] Furthermore, the process of marking a second scale Sk2 between a pair of first scales Sk1 may be performed multiple times. For example, a second scale Sk2 may be marked midway between a pair of first scales Sk1. Then, another second scale Sk2 may be marked midway between the first scales Sk1 and the second scales Sk2. This divides the space between the pair of first scales Sk1 into four equal parts, resulting in three markings of the second scales Sk2. This method allows for gradually increasing the resolution of the scales Sk. In the example described above, the camera 110 detects the first scale Sk1. Then, the second scale Sk2 is marked based on the position of the detected first scale Sk1. However, instead of detecting the first scale Sk1, a similar marker or the like may also be detected.

[0050] Furthermore, steps 105 to 106 can be considered a second marking process in which a second scale Sk2 is marked in addition to the first scale Sk1 that was marked in the first marking process. Furthermore, the first and second marking steps can be considered as marking steps for marking the scale Sk. In these marking steps, when the motor 341 is operated, markings are made corresponding to predetermined movement positions of the motor 341.

[0051] Motor 341 is pre-equipped with an encoder mirror 344a. In this state, motor 341 is placed on table 100. Furthermore, in steps 102 to 103, motor 341 is rotated. As described above, motor 341 rotates by being in a predetermined energizing mode. In response to this rotation, the first scale Sk1 is marked on the encoder mirror 344a. In steps 105 to 106, alignment is performed on table 100 based on the image of the encoder mirror 344a. Then, the second scale Sk2 is marked between the first scale Sk1.

[0052] In the example described above, the second marking process was performed using table 100, but it is not necessary to use table 100. For example, when marking the encoder mirror 344a after deceleration, motor control is performed using the encoder mirror 344a before deceleration. Alternatively, a mechanism other than a table that can adjust the position with high precision may be used. For example, a mechanism that adjusts the position using a high-precision motor may be used. Alternatively, for example, the table 100 could be positioned mechanically using a jig without using the camera 110. Also, in step 107, it was determined whether the motor 341 had completed one rotation, but this could also be determined by whether a predetermined resolution had been reached.

[0053] Figure 11 is a block diagram showing the functional configuration of the control device 150 that controls the motor 341 and the table 100 in the first embodiment. The control device 150 includes a state control unit 151, a position control unit 152, a position information acquisition unit 153, a table control unit 154, a motor control unit 155, and a marking control unit 156. The state control unit 151 manages the process based on configuration information such as actuator information. The process includes, for example, the first marking process, the placement process, and the second marking process. The state control unit 151 also specifies the next position to move to to the position control unit 152. Furthermore, the state control unit 151 instructs the marking control unit 156 to mark the scale Sk. The position control unit 152 controls the position of the motor 341 and the table 100 in response to requests from the state control unit 151. In the first marking step, the position control unit 152 specifies the energization mode to the motor control unit 155. In the second marking step, the position control unit 152 acquires the current position from the position information acquisition unit 153 as needed. Based on this position information, the position control unit 152 controls the motor 341 and the position of the table 100.

[0054] The position information acquisition unit 153 controls a device such as a camera 110 that acquires position information in response to a request from the state control unit 151. The position information acquisition unit 153 then acquires the position of the encoder mirror 344a on the table 100. The table control unit 154 controls the table 100 in response to a request from the state control unit 151. The table 100 may also be equipped with sensors to detect its position, etc., and the information from these sensors may be utilized. Examples of such sensors include distance sensors, color sensors, and laser sensors. The motor control unit 155 controls the motor 341 in response to a request from the state control unit 151. The marking control unit 156 controls the printer 120 in response to a request from the state control unit 151 to mark the scale Sk.

[0055] [Second Embodiment] In the second embodiment, the first marking step marks the scale Sk relative to the origin position of the encoder mirror 344a. The other scale Sks are then marked in the second marking step. The second embodiment is applicable to both the encoder 344 used before and after deceleration by the gearbox 342.

[0056] Figure 12 is a flowchart illustrating the method for marking the scale Sk in the second embodiment. First, the motor 341 is placed on the table 100 (step 201). Step 201 is the same as step 101 in Figure 6 and is a placement step. As in the first embodiment, the motor 341 is pre-equipped with an encoder mirror 344a. Next, the power supply state of the star connection is set to a predetermined power supply mode. This position then becomes the origin position of the encoder mirror 344a (step 202). Then, the first scale Sk1 is marked (step 203). That is, the scale Sk1 is marked relative to the origin position of the encoder mirror 344a. In this case, the first marking step can also be described as marking the first scale Sk1, which will be the origin for determining the mechanical angle of the motor 341.

[0057] Steps 204 to 206 are the same as steps 105 to 107 in Figure 6, and constitute the second marking process. However, in the second marking process, the second scale Sk2 is not marked between the pre-marked first scales Sk1. In this case, the table 100 is rotated sequentially in the θ direction around the central axis C, based on the first scale Sk1 marked at the origin. Then, the second scale Sk2 is marked. That is, the second scale Sk2 is marked at regular intervals. It can also be said that the second scale Sk2 is marked at regular angle intervals.

[0058] Figures 13(a) to 13(g) illustrate specific operational examples of steps 202 to 205 in Figure 12. Figure 13(a) shows the energization mode of step 202 in Figure 12 and the first scale Sk1 that is marked at this time. In the energizing mode, current is supplied from the W-phase terminal through the neutral point N to the U-phase terminal. At this time, the scale Sk1 is marked at the position where the motor 341 has rotated. Figure 13(a) corresponds to steps 202 to 203 in Figure 12. Then, as shown in Figure 13(b), the encoder mirror 344a attached to the motor 341 placed on the table 100 is photographed by the camera 110. Furthermore, as shown in Figure 13(e), the real image is aligned with the target image. Then, as shown in Figure 13(e), the second scale Sk2 is marked using the printer 120. Next, as shown in Figures 13(c) and (f), the table 100 is rotated to mark a second second scale Sk2. Furthermore, as shown in Figures 13(d) and (g), the table 100 is rotated to mark a third second scale Sk2. This process is then repeated. Figures 13(b) to (g) correspond to steps 204 to 205 in Figure 12. Thus, the second marking step marks the second scale Sk2, which is a mark other than the first scale Sk1 that serves as the origin.

[0059] [Third Embodiment] In the first and second embodiments, the method can be applied to encoders 344 used before and after reduction of the speed reducer 342. On the other hand, in the third embodiment, it is applied to encoders 344 used after reduction. In the third embodiment, the entire scale Sk is marked by the second marking step. Figure 14 is a flowchart illustrating the method for marking the scale Sk in the third embodiment. Step 301 is the same as step 201 in Figure 12 and is a placement process. Steps 302 to 303 are the same as steps 204 to 205 in Figure 12 and are a second marking process. In this second marking step, the motor 341 is rotated by a predetermined amount of rotation. In response, the encoder mirror 344a rotates sequentially in the θ direction around the central axis C via the reduction gear 342. Then, the second scale Sk2 is marked at this rotated position. The amount of rotation of the motor 341 can be detected by using an encoder that detects the mechanical angle of the motor 341 before reduction by the reduction gear 342. If the resolution of the encoder 344 after reduction is to be higher than that of the encoder 344 before reduction, the following is done. That is, the first scale Sk1 is marked by controlling the motor 341 using the encoder 344 before reduction. Then, as in the first embodiment, the second scale Sk2 is marked between the first scales Sk1 using the table 100 and the camera 110.

[0060] Figures 15(a) to 15(f) illustrate specific operational examples of steps 302 to 303 in Figure 14. First, as shown in Figure 15(a), the encoder mirror 344a placed on the table 100 is photographed by the camera 110. Next, as shown in Figure 15(d), the real image is aligned with the target image. Then, as shown in Figure 15(d), the second scale Sk2 is marked using the printer 120. Next, as shown in Figures 15(b) and (e), the motor 341 or table 100 is rotated to mark a second second scale Sk2. Furthermore, as shown in Figures 15(c) and (f), the table 100 is rotated to mark a third second scale Sk2. This process is then repeated. Figures 15(a) to (f) correspond to steps 302 to 303 in Figure 14.

[0061] Furthermore, in step 304, it is determined whether the motor 341 has rotated by the reduction ratio of the gearbox 342 (step 304). That is, it is determined whether the encoder mirror 344a has rotated once. As a result, if motor 341 does not rotate by the reduction ratio (No in step 304), return to step 302. Conversely, if motor 341 rotates by the reduction ratio (Yes in step 304), the series of processes is terminated.

[0062] In the third embodiment, the first marking step is omitted. In the third embodiment, the rotational position of the motor 341 is controlled by a pre-deceleration encoder, which is an encoder attached to the motor 341 before deceleration. Then, in the second marking step, a second scale Sk2 is marked on the position where the deceleration encoder mirror 344a has rotated, corresponding to the rotational position of the motor 341.

[0063] [Fourth Embodiment] In the example described above, the motor 341 was a three-phase brushless motor. In contrast, in the fourth embodiment, a two-phase brushless motor is used as the motor 341. The method for marking the scale Sk in the fourth embodiment is the same as in Figure 6. The fourth embodiment can be applied to either the encoder 344 used before or after the reduction gear 342. However, the following description will focus on the case where the scale Sk is marked on the encoder 344 used before the reduction gear.

[0064] Figure 16(a) shows the energization modes of a two-phase brushless motor. Figure 16(b) shows the first scale Sk1 that is marked in this mode. In case (1), as shown in Figure 16(a), the main magnet attached to the rotor 341a of the motor 341 faces the direction of the magnetic flux. That is, the N pole faces upward in the figure. In conjunction with this, the encoder mirror 344a rotates. Then, as shown in Figure 16(b), the first scale Sk1 is marked at the rotated position.

[0065] In case (2), as shown in Figure 16(a), the main magnet attached to the rotor 341a of the motor 341 faces the direction of the magnetic flux. That is, the rotor 341a rotates 1 / 4 turn, and the N pole faces to the right in the figure. In conjunction with this, the encoder mirror 344a also rotates. Then, as shown in Figure 16(b), the first scale Sk1 is marked at the rotated position.

[0066] In case (3), as shown in Figure 16(a), the main magnet attached to the rotor 341a of the motor 341 faces the direction of the magnetic flux. That is, the rotor 341a rotates 1 / 4 turn, and the N pole faces downwards in the figure. In conjunction with this, the encoder mirror 344a also rotates. Then, as shown in Figure 16(b), the first scale Sk1 is marked at the rotated position.

[0067] In case (4), as shown in Figure 16(a), the main magnet attached to the rotor 341a of the motor 341 faces the direction of the magnetic flux. That is, the rotor 341a rotates 1 / 4 turn, and the N pole faces to the left in the figure. In conjunction with this, the encoder mirror 344a also rotates. Then, as shown in Figure 16(b), the first scale Sk1 is marked at the rotated position. When power is applied sequentially in the power supply modes (1) to (4) described above, the rotor 341a of the motor 341 rotates once. After marking the first scale Sk1, the second scale Sk2 is marked between the first scale Sk1, similar to the first embodiment.

[0068] The scale marking method shown in Figures 6, 12, and 14, described above, can be considered a method for manufacturing the encoder mirror 344a. Furthermore, this scale marking method can also be considered a method for manufacturing the encoder 344, including the marking process.

[0069] According to the scale marking method described above, the encoder mirror 344a marks the scale Sk at a location corresponding to a predetermined movement position of the motor 341 when the motor 341 is operated. The motor 341 mentioned above is a rotary electric motor. Therefore, it can be said that the scale Sk is marked in the direction of rotation, corresponding to a predetermined mechanical angle of the motor 341. In other words, the scale Sk is marked on the encoder mirror 344a, which does not have a scale Sk mark, in accordance with the rotation of the motor 341. This makes it possible to match the rotation position (mechanical angle) of the motor 341 with the detection result (count) of the encoder 344 that is actually measured.

[0070] Figures 17(a) and 17(b) show the detection results of a conventional encoder. In Figure 17(a), the horizontal axis represents time, and the vertical axis represents the count on the scale Sk. Figure 17(b) is a magnified view of the portion indicated by XVIIB in Figure 17(a). The solid line in the figure shows the detection result by a conventional encoder. The dotted line shows the theoretical detection result that should be detected. In this case, the motor 341 is rotating at a constant speed, and ideally, the relationship between time and the count should be a straight line, as shown by the dotted line. However, due to factors such as mechanical errors, in reality, it is not a straight line, as shown by the solid line. In such cases, there is no consistency between the electrical angle, the mechanical angle and the detection result (count). For example, the count when the motor's mechanical angle changes from 0° to 90° will not match the count when it changes from 90° to 180°. Factors that can cause such phenomena include, for example, uneven winding of the coil Co of the stator 341b. Furthermore, mechanical errors can also be cited as a contributing factor. An example of a mechanical error is the misalignment of the central axis between the encoder before reduction by the speed reducer 342 (pre-reduction encoder) and the encoder after reduction.

[0071] Figure 18(a) is a conceptual diagram showing the misalignment of the central axes of the encoder before and after reduction by the speed reducer 342. Figure 18(b) shows the angular error that occurs between the encoder before and after deceleration when a misalignment of the central axis occurs. Here, the horizontal axis represents the count of the scale Sk, and the vertical axis represents the angular error. In other words, the angle shown by the encoder before deceleration and the angle shown by the encoder after deceleration are different, resulting in the difference shown in the figure. This is difficult to correct in the conventional assembly method in which the encoder mirror 344a is marked with the scale Sk before being assembled into the actuator 34. That is, even with calibration, it is difficult to correct this angular error.

[0072] On the other hand, in this embodiment, even if the aforementioned mechanical errors occur, the rotational position (mechanical angle) of the motor 341 and the detection result (count) of the encoder 344 that is actually measured can be matched. Therefore, even if there is a misalignment of the central axis between the encoder 344 before deceleration (pre-deceleration encoder) and the encoder 344 after deceleration, it is less likely to be affected. As a result, the detection accuracy of the mechanical angle of the motor 341 is improved. Furthermore, the calibration process performed after assembly can be omitted. In addition, because the detection accuracy of the mechanical angle is high, high-precision control of the motor 341 becomes possible even with a low-resolution encoder. Furthermore, high-precision control of the actuator 34 using this encoder 344 is possible. This encoder 344 is particularly effective when used for actuators 34 close to the base of the robot 30. That is, actuators 34 close to the base of the robot 30 have a significant impact on the positioning accuracy of the tip of the hand 31, so this is where it becomes even more effective.

[0073] Furthermore, in the first and fourth embodiments, the scale Sk is applied in two steps. Specifically, the first scale Sk1 is marked in the first marking step, and then the second scale Sk2 is marked in the second marking step. In this case, the coil Co that operates the motor 341 is energized in a predetermined energizing mode. The first scale Sk1 is marked at the position where the encoder mirror 344a has rotated. In addition to the first scale Sk1, a second scale Sk2 is also marked on the encoder mirror 344a. The second scale Sk2 is marked between the pair of first scales Sk1. The rotational position (mechanical angle) of the motor 341 can be controlled by selecting the energizing mode. Furthermore, in the energizing mode described above, the magnetic flux of the motor 341 is stable, and its rotational position is also stable. Therefore, the positional accuracy of the markings on the first scale Sk1 is high. The second scale Sk2 is marked between the first scales Sk1. Marking the second scale Sk2 results in an encoder with high resolution. For example, the table 100 described above is used to mark the second scale Sk2. The table 100 is equipped with a camera 110. Furthermore, the camera 110 enables high-precision alignment by using the captured images. This improves the positional accuracy of the markings on the second scale, Sk2. Furthermore, dividing the marking process into two steps can suppress thermal deformation of the encoder mirror 344a when using laser marking.

[0074] In the second embodiment, the first marking step marks the first scale Sk1 at the origin position. The other scales Sk are then marked as the second scale Sk2 in the second marking step. In this case, the first scale Sk1 is marked at the origin that defines the mechanical angle of the motor 341. The second scale Sk2 is a scale other than the first scale Sk1 which is the origin. According to the second embodiment, the motor 341 itself is used to determine the origin and mark the first scale Sk1. Therefore, the accuracy of the origin position can be improved. This makes it possible to control the motor 341 with high precision even when using a low-resolution encoder 344.

[0075] Furthermore, in the third embodiment, the reduction gear 342 marks the scale Sk of the reduced encoder. In the third embodiment, the scale Sk is marked on the reduced encoder mirror 344a. This rotational position corresponds to the rotational position of the motor 341 determined by the encoder before reduction. In this case, even if there is a misalignment of the central axes between the encoder before deceleration and the encoder after deceleration, it will have little effect. As a result, the detection accuracy of the mechanical angle of the motor 341 is improved.

[0076] In some cases, the motor 341 may be equipped with the aforementioned Hall sensor. In this case, the Hall sensor may be used in conjunction with the motor to position the location where the scale Sk is marked. This improves the positional accuracy of the location where the scale Sk is marked. Furthermore, positioning may be performed using sensors other than the Hall sensor. Furthermore, the actuator 34 may have backslash. In this case, a load may be applied to the rotation mechanism of the encoder mirror 344a to prevent backslash from occurring. Furthermore, when energizing using the above energizing mode, vector control may be used. When performing vector control, information on the mechanical angle of the motor 341 is required. In this embodiment, the accuracy of the mechanical angle information is improved by using the encoder 344 described above. As a result, the accuracy of the vector control is also improved, and the advantages of vector control are further realized. Advantages of vector control include low energy consumption and the ability to perform fine-grained control. Another advantage of vector control is that the rotation of the motor 341 can be efficiently controlled from low speed to high speed.

[0077] Furthermore, in the example described above, the encoder mirror 344a was used as the encoder scale. However, this applies to optical encoders; in the case of magnetic encoders, it does not necessarily have to be a "mirror". Furthermore, although the above example used an actuator 34 provided on a robot 30 as an example, the explanation is not limited to this. For example, it may also be applied to an actuator provided on a wearable muscle-assist device.

[0078] Furthermore, while the above example used a brushless motor as the rotary electric motor, a stepping motor could also be used. Furthermore, while the above example used a rotary electric motor for explanation, it is not limited to this. For example, the motor could be a linear motor.

[0079] Figure 19(a) shows a linear motor. The linear motor 200 shown in the figure comprises a moving element 210, a permanent magnet array 220, and an encoder mirror 230. The mobile element 210 is equipped with an electromagnet array 210a and moves to the right in the figure. The permanent magnet array 220 consists of permanent magnets arranged so that the north poles and south poles alternate. In the linear motor 200, the polarity of the electromagnet array 210a provided on the moving element 210 is sequentially switched according to its position. Then, by utilizing the attractive and repulsive forces between the electromagnet array 210a and the permanent magnet array 220, the moving element 210 moves along the permanent magnet array 220. The encoder mirror 230 marks a scale Sk corresponding to the position of the movable element 210 of the linear motor 200. The location where the scale Sk is marked is, for example, the position where the movable element 210 is stable.

[0080] Figure 19(b) shows the process of sequentially marking the scale Sk. As shown in Figure 19(b), the scale Sk is sequentially marked using, for example, a laser marker Rm, while changing the marking location. The encoder mirror 230 is marked with the scale Sk corresponding to the position of the movable element 210 of the linear motor 200. [Explanation of Symbols]

[0081] 1…Robot system, 10…Photography device, 20…Image processing device, 30…Robot, 31…Hand, 32…Arm, 33…Robot control unit, 34…Actuator, 100…Table, 110…Camera, 120…Printer, 200…Linear motor, 210…Motor, 220…Permanent magnet array, 230, 344a…Encoder mirror, 341…Motor, 341a…Rotor, 341b…Stator, 342…Reducer, 343…Rotating shaft, 344…Encoder, Sk…Scale, Sk1…First scale, Sk2…Second scale

Claims

1. A method for manufacturing an encoder, comprising an encoder scale that moves in conjunction with a motor and has multiple scales marked in the direction of movement for determining the motor's position, The process includes a marking step in which, when the motor is operated, the scale is marked in accordance with a predetermined movement position of the motor. The motor is a brushless motor, The marking step includes a first marking step of marking a first scale at the location where the encoder scale rotates when the coil that operates the brushless motor is energized in a predetermined energizing mode, The first marking step is a method for manufacturing an encoder, in which the first marking step is performed by applying power multiple times for one of the energizing modes to position the location to mark the first scale.

2. A method for manufacturing an encoder, comprising an encoder scale that moves in conjunction with a motor and has multiple scales marked in the direction of movement for determining the motor's position, The process includes a marking step in which, when the motor is operated, the scale is marked in accordance with a predetermined movement position of the motor. The motor is a brushless motor, The marking step includes a first marking step of marking a first scale at the location where the encoder scale rotates when the coil that operates the brushless motor is energized in a predetermined energizing mode, The first marking step is a method for manufacturing an encoder, in which the motor is energized in both forward and reverse directions for one of the energizing modes to position the location to mark the first scale.

3. A method for manufacturing an encoder, comprising an encoder scale that moves in conjunction with a motor and has multiple scales marked in the direction of movement for determining the motor's position, The process includes a marking step in which, when the motor is operated, the scale is marked in accordance with a predetermined movement position of the motor. The motor is a brushless motor, The marking step includes a first marking step of marking a first scale at the location where the encoder scale rotates when the coil that operates the brushless motor is energized in a predetermined energizing mode, The process further includes a second marking step in which a second scale is marked in addition to the first scale marked in the first marking step, The process includes placing the motor, which is equipped with the encoder scale, on a table that can move the encoder scale in the horizontal and rotational directions, The second marking step is a method for manufacturing an encoder, wherein the encoder scale is moved horizontally and rotationally by moving the table according to the position of the first scale, and the second scale is marked.

4. A method for manufacturing an encoder, comprising an encoder scale that moves in conjunction with a motor and has multiple scales marked in the direction of movement for determining the motor's position, The process includes a marking step in which, when the motor is operated, the scale is marked in accordance with a predetermined movement position of the motor. The motor is a brushless motor, The marking step includes a first marking step of marking a first scale at the location where the encoder scale rotates when the coil that operates the brushless motor is energized in a predetermined energizing mode, The process further includes a second marking step in which a second scale is marked in addition to the first scale marked in the first marking step, A method for manufacturing an encoder, wherein at least one of the first marking step and the second marking step is used in combination with a Hall sensor attached to the brushless motor to position the location where the scale is to be marked.

5. A method for manufacturing an encoder, comprising an encoder scale that moves in conjunction with a motor and has multiple scales marked in the direction of movement for determining the motor's position, The process includes a marking step in which, when the motor is operated, the scale is marked in accordance with a predetermined movement position of the motor. The motor is a brushless motor, The marking step includes a first marking step of marking a first scale at the location where the encoder scale rotates when the coil that operates the brushless motor is energized in a predetermined energizing mode, The process further includes a second marking step in which a second scale is marked in addition to the first scale marked in the first marking step, A method for manufacturing an encoder, wherein at least one of the first marking step and the second marking step applies a load to the rotation mechanism of the encoder scale so as not to cause backslashes.

6. A method for manufacturing an encoder, comprising an encoder scale that moves in conjunction with a motor and has a plurality of scales marked in the direction of movement for determining the position of the motor, The process includes a marking step in which, when the motor is operated, the scale is marked in accordance with a predetermined movement position of the motor. The motor is a brushless motor, The marking step includes a first marking step of marking a first scale at the location where the encoder scale rotates when the coil that operates the brushless motor is energized in a predetermined energizing mode, The process further includes a second marking step in which a second scale is marked in addition to the first scale marked in the first marking step, The motor is a rotary electric motor, The rotational position of the aforementioned rotary electric motor is controlled by a pre-deceleration encoder, which is an encoder attached to the rotary electric motor before deceleration. The marking step is a method for manufacturing an encoder, in which the marking step marks the position of the encoder scale after deceleration, corresponding to the rotation position of the rotary electric motor.

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