A calibration device for a magnetic encoder

Abstract

The utility model belongs to the technical field of encoder, provide a kind of calibration device of magnetic encoder, comprising: platform, the platform with the hole in middle part;Servo motor, fixedly installed in the middle part of platform, its output shaft passes through hole downward;Reference encoder, be located below platform and be connected with the lower end of output shaft by stabilizing assembly;And the magnetic encoder to be calibrated, be connected with the upper end of output shaft and be supported in the upper end cover of servo motor by supporting assembly;Wherein, stabilizing assembly includes shaft cylinder and flywheel, shaft cylinder upper part is located between output shaft and reference encoder to realize coaxial connection of both, flywheel is sleeved on the lower part of shaft cylinder to increase the rotational inertia of output shaft.The utility model provides stable angle reference or speed reference for the calibration of magnetic encoder by stabilizing assembly, can improve the calibration quality of magnetic encoder error, effectively improve its angle precision after calibration.

Description

Technical Field

[0001] This utility model relates to the field of encoder technology, and specifically to a calibration device for a magnetic encoder. Background Technology

[0002] A magnetic encoder is a new type of angle or displacement measuring device. Its principle is to use magnetoresistive or Hall elements to measure the angle or displacement value of a changing magnetic material. The change in angle or displacement of the magnetic material will cause a certain change in resistance or voltage. The change is amplified by an amplification circuit, and after being processed by a microcontroller, a pulse signal or analog signal is output to achieve the measurement purpose.

[0003] Currently, the accuracy of magnetic encoder angles is directly affected by the production, processing, and assembly of the induction magnetic poles. Conventional calibration methods use stable speed or angle comparisons to calibrate the magnetic encoder, requiring a stable speed or angle reference, typically provided by a servo motor and a reference encoder. However, servo motors are affected by shaft assembly errors and cogging torque fluctuations, resulting in periodic disturbance torque during operation and causing speed fluctuations, making it impossible to output a stable speed. Furthermore, the coaxiality between the reference encoder and the servo motor's output shaft cannot be guaranteed, making the reference encoder's own positioning angle inaccurate. This leads to low calibration quality and poor repeatability of the magnetic encoder. Utility Model Content

[0004] To address the shortcomings of existing technologies, this utility model provides a magnetic encoder calibration device to solve the problems of low calibration quality and poor repeatability of magnetic encoders caused by the inability of existing servo motors to output stable speeds and the inaccuracy of the positioning angle of the reference encoder itself.

[0005] To achieve the above objectives, the present invention provides the following technical solution:

[0006] A calibration device for a magnetic encoder, comprising:

[0007] A platform, having a central through-hole;

[0008] A servo motor is fixedly installed in the middle of the platform, and its output axis passes downward through the through hole.

[0009] A reference encoder, located below the platform and connected to the lower end of the output shaft via a stabilizing assembly; and

[0010] The magnetic encoder to be calibrated is connected to the upper end of the output shaft and supported by a support assembly on the upper cover of the servo motor.

[0011] The stabilizing component includes a shaft cylinder and a flywheel. The upper part of the shaft cylinder is located between the output shaft and the reference encoder to achieve coaxial connection between the two. The flywheel is fitted onto the lower part of the shaft cylinder to increase the rotational inertia of the output shaft.

[0012] In one embodiment disclosed in this application, the fixed part of the reference encoder is fixedly connected to the bottom surface of the platform by screws, and the rotating part is fitted onto the outer side of the upper part of the shaft cylinder;

[0013] The inner side of the upper part of the cylinder is connected to the lower end of the output shaft through a first expansion sleeve;

[0014] The flywheel is fitted onto the lower outer side of the shaft cylinder via a second expansion sleeve.

[0015] In one embodiment disclosed in this application, the flywheel diameter is 400 mm.

[0016] In one embodiment disclosed in this application, the current loop bandwidth of the servo driver of the servo motor is between 1500 and 2500 Hz.

[0017] In one embodiment disclosed in this application, the rotating part of the magnetic encoder is connected to the upper end of the output shaft via a coupling;

[0018] The support assembly includes a first flexible support ring, a spring connector, and a second flexible support ring connected in sequence.

[0019] The first flexible support ring is fitted around the fixed part of the magnetic encoder and its top is detachably connected to the latter by screws;

[0020] The second flexible support ring is detachably connected to the upper end cap by screws.

[0021] In one embodiment disclosed in this application, the spring connector has an integrally formed connecting ring and a U-shaped spring foot, and the connecting ring is detachably connected to the bottom of the first flexible support ring by screws;

[0022] The U-shaped spring feet are evenly distributed around the outer circumference of the connecting ring, and each U-shaped spring foot is detachably connected to the top of the second flexible support ring by a screw.

[0023] In one embodiment disclosed in this application, the spring connector is made of stainless steel.

[0024] In one embodiment disclosed in this application, the four corners of the platform are respectively threaded with support legs for supporting the platform and adjusting the platform's level.

[0025] In one embodiment disclosed in this application, the root of the support leg is a disc.

[0026] In one embodiment disclosed in this application, a handle is connected to the top surface of the platform;

[0027] The handle has four evenly distributed around the circumference of the servo motor.

[0028] Compared with the prior art, the beneficial effects of this utility model are:

[0029] 1. By using stabilizing components to provide a stable angle or speed reference for the calibration of magnetic encoders, the calibration quality of magnetic encoder errors can be improved, effectively enhancing the calibrated angle accuracy.

[0030] 2. By compensating for the deformation of the U-shaped spring foot, the installation deviation of the magnetic encoder can be reduced or automatically corrected to ensure the coaxiality between the magnetic encoder and the output shaft. This ensures that the axis of the magnetic encoder is highly aligned with the axis of the reference encoder, further improving the calibration quality of the magnetic encoder error. At the same time, it can protect the magnetic encoder from damage during the calibration process. In addition, the first flexible support ring, the spring connector, and the second flexible support ring are detachable and replaceable, allowing for the installation of different models of magnetic encoders for calibration, thus improving the applicability of this calibration device.

[0031] 3. The large area support of the disc improves the stability of the calibration device, thereby ensuring the calibration quality of the magnetic encoder error. Attached Figure Description

[0032] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0033] Figure 1 This is a three-dimensional structural diagram of the present invention;

[0034] Figure 2 This is a schematic diagram of the main cross-section of the present invention;

[0035] Figure 3 for Figure 2 A magnified schematic diagram of section A in the middle;

[0036] Figure 4 This is a three-dimensional structural diagram of the spring connector. Detailed Implementation

[0037] In the following description, only certain exemplary embodiments are briefly described. As those skilled in the art will recognize, the described embodiments can be modified in various ways without departing from the spirit or scope of this invention. Therefore, the drawings and description are considered exemplary in nature and not restrictive.

[0038] In the description of this utility model, it should be understood that the terms "center", "longitudinal", "lateral", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this utility model and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model.

[0039] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this utility model, "a plurality of" means two or more, unless otherwise explicitly specified.

[0040] In this utility model, unless otherwise explicitly specified and limited, the terms "installation," "connection," "joining," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. For those skilled in the art, the specific meaning of the above terms in this utility model can be understood according to the specific circumstances.

[0041] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0042] The following disclosure provides many different embodiments or examples for implementing various structures of this invention. To simplify the disclosure, specific examples of components and arrangements are described below. Of course, these are merely examples and are not intended to limit the scope of this invention.

[0043] The embodiments of this utility model will now be described in detail with reference to the accompanying drawings.

[0044] See Figures 1-4 As shown, this utility model provides a calibration device for a magnetic encoder, comprising:

[0045] The stage 100 has a platform 110 with a through hole in the middle;

[0046] The servo motor 200 is fixedly installed in the middle of the platform 110, and its output shaft 210 passes downward through the through hole.

[0047] A reference encoder 300 is located below the platform 110 and connected to the lower end of the output shaft 210 via a stabilizing assembly 400; and

[0048] The magnetic encoder 500 to be calibrated is connected to the upper end of the output shaft 210 and supported by the support assembly 600 on the upper end cover 220 of the servo motor 200.

[0049] The stabilizing component 400 includes a shaft cylinder 410 and a flywheel 420. The upper part of the shaft cylinder 410 is located between the output shaft 210 and the reference encoder 300 to achieve coaxial connection between the two. The flywheel 420 is fitted onto the lower part of the shaft cylinder 410 to increase the rotational inertia of the output shaft 210.

[0050] Specifically, the output shaft 210 of the servo motor 200 extends out of its housing at both ends, with a larger diameter at the lower end and a smaller diameter at the upper end. The upper cover 220 is hollow to facilitate the connection of the magnetic encoder 500 to be calibrated to the upper end of the output shaft 210. The fixed part of the reference encoder 300 is fixedly connected to the bottom surface of the platform 110 by screws, and the rotating part is fitted onto the outer side of the upper part of the shaft cylinder 410. The inner side of the upper part of the shaft cylinder 410 is connected to the lower end of the output shaft 210 through a first expansion sleeve 430, and the flywheel 420 is fitted onto the outer side of the lower part of the shaft cylinder 410 through a second expansion sleeve 440. By using the shaft cylinder 410 and the first expansion sleeve 430, the installation deviation of the reference encoder 300 can be reduced, thereby ensuring the coaxiality between the reference encoder 300 and the output shaft 210, and thus improving the accuracy of the positioning angle of the reference encoder 300 itself, providing a stable angular reference for the calibration of the magnetic encoder 500. The use of shaft sleeve 410 and second expansion sleeve 440 ensures the coaxiality between flywheel 420 and output shaft 210, and allows flywheel 420 to rotate synchronously with output shaft 210 to increase the rotational inertia of output shaft 210 and reduce its speed fluctuation (explanation of principle: servo motor 200, as a permanent magnet AC motor, has cogging effect, that is, there will be periodic disturbance torque during operation. Although the magnitude of cogging torque can be reduced through design, torque fluctuation will still cause speed fluctuation, which will be converted into deviation of theoretical angle, resulting in poor calibration quality of magnetic encoder 500; by installing flywheel 420 at the lower end of output shaft 210, the disturbance torque remains unchanged, the rotational inertia of the shaft system increases, the disturbance torque acceleration decreases, and the speed fluctuation of the shaft system decreases), providing a stable speed reference for the calibration of magnetic encoder 500. Thus, this calibration device can provide high-quality stable operating conditions in speed closed-loop mode or high-quality angular positioning accuracy in position closed-loop mode to calibrate the angular error of the magnetic encoder 500. Then, the built-in program corrects the magnetic encoder 500 to achieve calibration. In other words, by providing a stable angular or speed reference for the calibration of the magnetic encoder 500 through the stabilizing component 400, the calibration quality of the magnetic encoder 500 error can be improved, effectively enhancing its calibrated angular accuracy.

[0051] The flywheel 420 has a diameter of 400mm. Thus, when the flywheel 420 rotates synchronously with the output shaft 210, a large moment of inertia can be generated.

[0052] To further mitigate the speed fluctuations of the output shaft 210, the current loop bandwidth of the servo driver of the servo motor 200 (i.e., the controller of the former, also known as a servo controller or servo amplifier, not shown in the figure) is between 1500 and 2500 Hz. This high current loop bandwidth (1500–2500 Hz) can compensate for and reduce the periodic disturbance torque of the servo motor 200, thereby reducing the speed fluctuations of the shaft system and providing a high-quality and stable speed reference for the calibration of the magnetic encoder 500.

[0053] See Figure 3 As shown, the rotating part of the magnetic encoder 500 is connected to the upper end of the output shaft 210 via a coupling 510; the support assembly 600 includes a first flexible support ring 610, a spring connector 620, and a second flexible support ring 630 connected in sequence. The first flexible support ring 610 is fitted around the fixed part of the magnetic encoder 500, and its top is detachably connected to the latter by screws. The second flexible support ring 630 is detachably connected to the upper end cover 220 by screws. Specifically, the spring connector 620 has an integrally formed connecting ring 621 and a U-shaped spring foot 622 (see details). Figure 4 As shown, the connecting ring 621 is detachably connected to the bottom of the first flexible support ring 610 by screws. Three U-shaped spring feet 622 are evenly distributed around the outer circumference of the connecting ring 621, and each U-shaped spring foot 622 is detachably connected to the top of the second flexible support ring 630 by screws. Through the deformation compensation of the U-shaped spring feet 622, the installation deviation of the magnetic encoder 500 can be reduced or automatically corrected to ensure the coaxiality between the magnetic encoder 500 and the output shaft 210, thereby making the axis of the magnetic encoder 500 highly coincident with the axis of the reference encoder 300, further improving the calibration quality of the magnetic encoder 500 error, and protecting the magnetic encoder 500 from damage during the calibration process. In addition, the first flexible support ring 610, the spring connector 620 and the second flexible support ring 630 are detachable and replaceable, so that different models of magnetic encoders 500 can be installed for calibration, improving the applicability of this calibration device.

[0054] In this embodiment, the spring connector 620 is preferably made of stainless steel. Stainless steel is rust-resistant, has strong deformation recovery ability, and a long service life.

[0055] See Figure 1 As shown, the four corners of the platform 110 are threaded with support legs 120, which are used to support the platform 110 and adjust the level of the platform 110.

[0056] The base of the support leg 120 is a disc 121. The large area of ​​the disc 121 provides support, which improves the stability of the calibration device and ensures the calibration quality of the magnetic encoder 500 error.

[0057] To facilitate the handling of this calibration device, a handle 130 is connected to the top surface of the platform 110, and four handles 130 are evenly distributed around the circumference of the servo motor 200.

[0058] The above embodiments are merely preferred embodiments of this utility model and are not intended to limit the technical solutions of this utility model. Any technical solution that can be implemented based on the above embodiments without creative effort should be considered to fall within the scope of protection of this utility model patent.

Claims

1. A calibration device for a magnetic encoder, characterized in that, include: A platform, having a central through-hole; A servo motor is fixedly installed in the middle of the platform, and its output axis passes downward through the through hole. A reference encoder, located below the platform and connected to the lower end of the output shaft via a stabilizing assembly; and The magnetic encoder to be calibrated is connected to the upper end of the output shaft and supported by a support assembly on the upper cover of the servo motor. The stabilizing component includes a shaft cylinder and a flywheel. The upper part of the shaft cylinder is located between the output shaft and the reference encoder to achieve coaxial connection between the two. The flywheel is fitted onto the lower part of the shaft cylinder to increase the rotational inertia of the output shaft.

2. The calibration device for the magnetic encoder according to claim 1, characterized in that: The fixed part of the reference encoder is fixedly connected to the bottom surface of the platform by screws, and the rotating part is fitted onto the outer side of the upper part of the shaft cylinder; The inner side of the upper part of the cylinder is connected to the lower end of the output shaft through a first expansion sleeve; The flywheel is fitted onto the lower outer side of the shaft cylinder via a second expansion sleeve.

3. The calibration device for the magnetic encoder according to claim 2, characterized in that, The flywheel has a diameter of 400mm.

4. The calibration device for a magnetic encoder according to any one of claims 1 to 3, characterized in that, The current loop bandwidth of the servo driver for the servo motor is between 1500 and 2500 Hz.

5. The calibration device for the magnetic encoder according to claim 1, characterized in that: The rotating part of the magnetic encoder is connected to the upper end of the output shaft via a coupling. The support assembly includes a first flexible support ring, a spring connector, and a second flexible support ring connected in sequence. The first flexible support ring is fitted around the fixed part of the magnetic encoder and its top is detachably connected to the latter by screws; The second flexible support ring is detachably connected to the upper end cap by screws.

6. The calibration device for the magnetic encoder according to claim 5, characterized in that: The spring connector has an integrally formed connecting ring and a U-shaped spring foot. The connecting ring is detachably connected to the bottom of the first flexible support ring by screws. The U-shaped spring feet are evenly distributed around the outer circumference of the connecting ring, and each U-shaped spring foot is detachably connected to the top of the second flexible support ring by a screw.

7. The calibration device for a magnetic encoder according to claim 5 or 6, characterized in that, The spring connector is made of stainless steel.

8. The calibration device for the magnetic encoder according to claim 1, characterized in that, The platform is threaded with legs at each of its four corners to support the platform and adjust its level.

9. The calibration device for a magnetic encoder according to claim 8, characterized in that, The base of the outrigger is a disc.

10. The calibration device for the magnetic encoder according to claim 1 or 8, characterized in that: A handle is connected to the top surface of the platform; The handle has four evenly distributed around the circumference of the servo motor.

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