In-situ correction reference encoder, system and method of high-precision encoder

Abstract

The invention discloses an in-situ correction reference encoder, system and method of a high-precision encoder, and relates to the field of encoders. The invention discloses an in-situ correction reference encoder of a high-precision encoder, the in-situ correction reference encoder is used for carrying out in-situ correction on a corrected encoder, the reference encoder comprises an elastic support and an integrated encoder body, and the elastic support is used for fixedly installing the integrated encoder body; the integrated encoder body comprises a bearing, a stator fixedly connected with an outer ring of the bearing, a rotor fixedly connected with an inner ring of the bearing and a rotating shaft, and the rotating shaft is fixedly connected with the rotor. According to the invention, after the calibrated encoder is installed on the tested device, the standard encoder is directly connected with the calibrated encoder through a connecting shaft for in-place correction, so that the high-precision requirement on the installation surface of the tested device is greatly reduced, the correction link requirement of the encoder in a factory is reduced, and the process cost is greatly reduced.

Description

Technical Field

[0001] The present invention relates to the field of encoder correction, and in particular to an on-site correction reference encoder, system and method for a high-precision encoder. Background Art

[0002] The encoder plays a vital role in the automation control system. It can accurately measure the position, angle or linear displacement of the measured object and provide accurate position feedback signals, thereby achieving precise positioning control. In the actual measurement process, the encoder's angle measurement accuracy will be affected by many factors such as the encoder's own error, installation error, and changes in environmental conditions. In order to ensure the performance of the encoder, the encoder needs to be calibrated.

[0003] There are generally two methods for calibrating high-precision encoders in existing technology.

[0004] The first method is to install the encoder on the device under test, connect the entire device to a reference encoder using a coupling and drag, and then use motor drag or other drag to synchronously collect the errors of the two and perform error compensation.

[0005] The second method is to use the installation accuracy transfer method to ensure that the encoder is installed at a high-precision position before leaving the factory, and perform calibration compensation at this position. Then, the extremely high installation accuracy is also guaranteed on the device under test, so that the previous calibration compensation value can continue to play a role and achieve the final high accuracy.

[0006] The first method requires the entire device under test to be coaxially dragged, which requires the device to be small and compact so that it can be assembled on the calibration table, which limits the use of this method. The second method requires that the entire encoder production process must be strictly installed with high precision before calibration, and the installation machine of the device under test must also meet extremely high installation accuracy to achieve precision transfer, which greatly increases the production accuracy and assembly complexity of the device under test, resulting in a significant increase in costs. Summary of the invention

[0007] In order to solve the above problems, the present invention provides an on-site correction reference encoder, system and method for a high-precision encoder.

[0008] In the first aspect, the present invention provides an in-situ calibration reference encoder for a high-precision encoder, which adopts the following technical solution:

[0009] A reference encoder for in-situ correction of a high-precision encoder, the reference encoder comprising: an elastic bracket and an integrated encoder body, the elastic bracket being used for fixedly installing the integrated encoder body; the integrated encoder body comprising a bearing, a stator fixedly connected to the outer ring of the bearing, a rotor fixedly connected to the inner ring of the bearing, and a rotating shaft, the rotating shaft comprising an expansion shaft and a core shaft that are nested and connected.

[0010] Preferably, an expansion chuck formed by a plurality of free ends is provided below the expansion shaft.

[0011] Preferably, the expansion shaft is an external expansion shaft, and the external expansion shaft is nested with the core shaft as a whole, and the inner hole on one side of the external expansion shaft at the nested connection is an inner conical surface, and the inner hole on one side of the core shaft is an outer conical surface.

[0012] Preferably, the expansion shaft is an inner expansion shaft, and the inner expansion shaft is nested with the core shaft as a whole, and the inner hole on one side of the inner expansion shaft at the nested connection is an outer cone surface, and the inner hole on one side of the core shaft is an inner cone surface.

[0013] Preferably, the upper end of the core shaft includes a plurality of screws for tightening or loosening the end face of the expansion shaft.

[0014] Preferably, the reference encoder further comprises a shell, and the shell is arranged outside the integrated encoder body and fixedly connected to the elastic bracket.

[0015] In a second aspect, the present invention provides an in-situ correction system for a high-precision encoder, which adopts the following technical solution:

[0016] An on-site calibration system for a high-precision encoder is used to calibrate the calibrated encoder on-site, and is characterized in that it includes: the calibrated encoder, a host computer, a device under test and a reference encoder. The calibrated encoder, the reference encoder and the device under test are fixed to a shaft and driven by the device under test to rotate synchronously. After the host computer collects at least one circle of data, it extracts the error curve and writes it into the calibrated encoder.

[0017] Preferably, the in-situ correction system is fixed to the calibrated encoder and the device under test by means of an expansion shaft clamp of the reference encoder.

[0018] In a third aspect, the present invention provides an on-site correction method for a high-precision encoder using the following technical solution:

[0019] A method for in-situ correction of a high-precision encoder is used to perform in-situ correction on an encoder to be corrected. The in-situ correction method comprises the following steps:

[0020] S1: The encoder to be calibrated is installed on the device under test;

[0021] S2: Connect and fasten the rotating shaft of the reference encoder to the device under test, making it coaxial with the device under test and the encoder to be corrected;

[0022] S3: driving the device under test to rotate, the reference encoder, the device under test and the encoder to be corrected to rotate synchronously, and synchronously collecting the angle data of the reference encoder and the encoder to be corrected;

[0023] S4: After the host computer collects at least one lap of data, it extracts the error curve and writes it into the encoder to be corrected to complete the correction;

[0024] S5: Remove the reference encoder and complete the installation.

[0025] Preferably, a specific implementation of S2 is:

[0026] S21: Fit the reference encoder shaft to the inner side of the calibrated encoder shaft;

[0027] S22: Tighten the screws symmetrically and cyclically. At this time, the cone surfaces of the core shaft and the expansion shaft squeeze each other, and the expansion chuck mating surface of the expansion shaft expands / contracts, fitting tightly with the inner edge of the encoder shaft to be measured;

[0028] S23: Pass the screw through the through hole of the elastic bracket and tighten it with the threaded hole on the encoder to be calibrated or the threaded hole on the device to be tested.

[0029] Compared with the prior art, the advantage of the present invention is that after the calibrated encoder is installed on the device under test, the reference encoder is directly connected to the calibrated encoder for in-situ calibration, which greatly reduces the high-precision requirements for the mounting surface of the device under test, while reducing the calibration requirements of the encoder in the factory, greatly reducing the process costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 The present invention is a schematic diagram of the cross-sectional structure of an in-situ correction reference encoder of a high-precision encoder according to an embodiment of the present invention.

[0031] Figure 2 The figure is a schematic diagram of an in-situ correction system for a high-precision encoder according to an embodiment of the present invention.

[0032] Figure 3 The present invention is a schematic diagram of an in-situ correction system for a high-precision encoder according to an embodiment of the present invention.

[0033] Figure 4 The present invention is a flowchart of a method for in-situ correction of a high-precision encoder according to an embodiment of the present invention.

[0034] Figure 5 It is a flowchart of a specific implementation of step 2 of an in-situ correction method for a high-precision encoder according to an embodiment of the present invention.

[0035] Description of reference numerals:

[0036] 1. Reference encoder, 10. Elastic bracket, 11. Stator, 12. Rotor, 13. Bearing, 14. External expansion shaft, 141. External expansion chuck, 15. Mandrel, 16. Set screw, 2. Encoder to be calibrated, 3. Device to be measured, 31. Frame, 32. Machine shaft. DETAILED DESCRIPTION

[0037] The present invention is further described in detail below in conjunction with the accompanying drawings.

[0038] like Figure 1 As shown, it is an embodiment of an in-situ calibration reference encoder of a high-precision encoder of the present invention, the reference encoder 1 comprises an elastic bracket 10 and an integrated encoder body, the integrated encoder body comprises a bearing 13 with extremely high absolute position accuracy, a stator 11 fixedly connected to the outer ring of the bearing 13, a rotor 12 parallel to the stator 11 and fixedly connected to the inner ring of the bearing 13, an external expansion shaft 14 fixedly connected to the rotor 12, one end of the external expansion shaft 14 is provided with an external expansion type chuck 141 formed by a plurality of free ends, and a core shaft 15 nested and fixed with the external expansion shaft 14. The connection method is that a part of the lower end of the core shaft 15 is embedded in the external expansion type chuck 141, the external expansion shaft 14 and the core shaft 15 are nested at the connection, the inner hole on one side of the external expansion shaft 14 is an inner cone surface, the inner hole on one side of the core shaft 15 is an outer cone surface, the upper end of the core shaft 15 comprises a plurality of screws 16, and the elastic bracket 10 is fixedly connected to the stator 11. The rotor 12 and stator 11 are connected by the bearing 13 which has extremely high absolute position accuracy, so that the mechanical rotation accuracy of the reference encoder 1 is extremely guaranteed. The rotating shaft composed of the outer expansion shaft 14 and the core shaft 15 can evenly transmit pressure to ensure uniform distribution of the clamping force. By adjusting the screw 16 included in the upper end of the core shaft 15, the end face of the outer expansion shaft can be tightened or loosened. The elastic bracket 10 is fixedly connected to the stator 11. When the encoder is working, the elastic bracket 10 absorbs the micro-motion of the stator 11 due to engineering errors, ensuring that the normal operation of the reference encoder 1 is not damaged.

[0039] like Figure 2 , Figure 3 As shown, it is an embodiment of an in-situ correction system of a high-precision encoder of the present invention, comprising: a reference encoder 1, a calibrated encoder 2, a host computer (not shown in the figure), and a device under test 3, wherein the calibrated encoder 2 is fixed on a frame 31 of the device under test 3, the reference encoder 1 and the calibrated encoder 2 are fastened to the shaft of the device under test 3 through an external expansion chuck 141, and the three are connected and fixedly connected as a whole, driving the rotation of the device under test 3, and the device under test 3 drives the synchronous rotation of the reference encoder 1 and the calibrated encoder 2, and after the host computer collects at least one circle of rotation data, the error curve is extracted and written into the calibrated encoder 2.

[0040] like Figure 4 , Figure 5 The figure shows an embodiment of an in-situ correction system of a high-precision encoder of the present invention, which comprises the following steps:

[0041] S1: The encoder to be calibrated is installed on the device under test;

[0042] S2: Connect and tighten the expansion shaft of the reference encoder to the device under test, making it coaxial with the device under test and the encoder to be corrected;

[0043] S3: driving the device under test to rotate, the reference encoder, the device under test and the encoder to be corrected to rotate synchronously, and synchronously collecting the angle data of the reference encoder and the encoder to be corrected;

[0044] S4: After the host computer collects at least one lap of data, it extracts the error curve and writes it into the encoder to be corrected to complete the correction;

[0045] S5: Remove the reference encoder and complete the installation.

[0046] Among them, a specific implementation method of S2 is:

[0047] S21: Fit the reference encoder to the inner side of the encoder shaft to be calibrated;

[0048] S22: Tighten the screws symmetrically and cyclically. At this time, the cone surfaces of the core shaft and the external expansion shaft squeeze each other, and the external expansion shaft clamp expands and fits tightly with the inner edge of the encoder shaft to be measured.

[0049] S23: Pass the screw through the through hole of the elastic bracket and tighten it with the threaded hole on the encoder to be calibrated or the threaded hole on the device to be tested.

[0050] The above are all preferred embodiments of the present invention, and are not intended to limit the protection scope of the present invention. Therefore, any equivalent changes made based on the structure, shape, and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. An in-situ calibration reference encoder for a high-precision encoder, characterized in that: The reference encoder includes: an elastic bracket and an integrated encoder body, the elastic bracket is used to fix the integrated encoder body; the integrated encoder body includes a bearing, a stator fixedly connected to the outer ring of the bearing, a rotor fixedly connected to the inner ring of the bearing, and a rotating shaft, the rotating shaft includes an expansion shaft and a core shaft that are nested and connected.

2. The in-situ calibration reference encoder for a high-precision encoder according to claim 1, characterized in that: An expansion chuck formed by a plurality of free ends is arranged below the expansion shaft.

3. The in-situ calibration reference encoder for a high-precision encoder according to claim 1, characterized in that: The expansion shaft is an external expansion shaft, and the external expansion shaft is nested with the core shaft as a whole. At the nested connection, the inner hole on one side of the external expansion shaft is an inner conical surface, and the inner hole on one side of the core shaft is an outer conical surface.

4. The in-situ calibration reference encoder for a high-precision encoder according to claim 1, characterized in that: The expansion shaft is an inner expansion shaft, and the inner expansion shaft is nested with the core shaft as a whole. At the nested connection, the inner hole on one side of the inner expansion shaft is an outer cone surface, and the inner hole on one side of the core shaft is an inner cone surface.

5. The in-situ calibration reference encoder for a high-precision encoder according to claim 1, characterized in that: The upper end of the core shaft includes a plurality of screws for tightening or loosening the end surface of the expansion shaft.

6. The in-situ calibration reference encoder for a high-precision encoder according to claim 1, characterized in that: The reference encoder further comprises a shell, which is arranged outside the integrated encoder body and fixedly connected to the elastic bracket.

7. A high-precision encoder in-situ calibration system, used for in-situ calibration of the calibrated encoder, characterized in that include: An in-situ calibration reference encoder for a high-precision encoder as described in any one of claims 1 to 6, wherein the calibrated encoder, the reference encoder and the device under test are fixed to a shaft and driven by the device under test to rotate synchronously. After the host computer collects at least one circle of data, it extracts the error curve and writes it into the calibrated encoder.

8. The in-situ correction system for a high-precision encoder according to claim 7, characterized in that: The in-situ correction system is fixed by coupling the expansion shaft of the reference encoder, the encoder to be corrected and the device to be measured.

9. An on-site calibration method for a high-precision encoder, used for calibrating an encoder to be calibrated on-site, using an on-site calibration system for a high-precision encoder as claimed in any one of claims 7 to 8, characterized in that: The in-situ correction method comprises the following steps: S1: The encoder to be calibrated is installed on the device under test; S2: Connect and fasten the rotating shaft of the reference encoder to the device under test, making it coaxial with the device under test and the encoder to be corrected; S3: driving the device under test to rotate, the reference encoder, the device under test and the encoder to be corrected to rotate synchronously, and synchronously collecting the angle data of the reference encoder and the encoder to be corrected; S4: After the host computer collects at least one lap of data, it extracts the error curve and writes it into the encoder to be corrected to complete the correction; S5: Remove the reference encoder and complete the installation.

10. The on-site calibration method of a high-precision encoder according to claim 9, which is used to perform on-site calibration on the calibrated encoder, characterized in that a specific implementation of S2 is: S21: Fit the reference encoder shaft to the inner side of the calibrated encoder shaft; S22: Tighten the screws symmetrically and cyclically. At this time, the cone surfaces of the core shaft and the expansion shaft squeeze each other, and the expansion chuck mating surface of the expansion shaft expands / contracts, fitting tightly with the inner edge of the encoder shaft to be measured; S23: Pass the screw through the through hole of the elastic bracket and tighten it with the threaded hole on the encoder to be calibrated or the threaded hole on the device to be tested.

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