Ultrahigh-resolution rotary table

Abstract

The invention relates to the technical field of precision measurement and control, in particular to an ultrahigh-resolution rotary table, which comprises an air floatation shaft system, an air floatation shaft system, a rotating shaft system, a rotating shaft system, a rotating shaft system and a rotating shaft system, and is characterized in that the air floatation shaft system comprises a bearing rotor and a bearing stator; the multi-reading-head grating feedback unit is connected with the air floating shaft system; the multi-reading-head signal processing unit is connected with a signal output end of the multi-reading-head grating feedback unit; the ceramic motor unit is fixed relative to the bearing stator and drives the bearing rotor to rotate; the servo control unit is connected with the multi-reading-head signal processing unit and the ceramic motor unit; according to the invention, synchronous acquisition and real-time average processing are carried out on angle signals through the multi-reading-head grating feedback unit, and electronic subdivision noise is reduced, so that the effective angle resolution of the grating is improved; through the friction driving mode of the ceramic motor unit and the design of uniform distribution, the inclination error possibly caused by single driving force is eliminated.

Description

Technical Field

[0001] The invention relates to the technical field of precision measurement and control, and in particular to an ultra-high resolution turntable. Background Art

[0002] In the fields of precision measurement, optoelectronic technology, and high-resolution encoder manufacturing, the demand for ultra-high-resolution angle generation equipment is growing. At present, high-precision turntables are widely used as standard equipment in angle measurement and angle sensor calibration, and their performance directly affects the accuracy of measurement and calibration results. However, the high-resolution angle generation problem that is prevalent in the existing technology has not been effectively solved.

[0003] Existing high-precision turntables mainly rely on grating encoders to provide angle feedback signals, and the improvement of grating resolution is limited by the design and manufacturing process. In addition, traditional drive methods (such as torque motor drive) have certain shortcomings in micron-level positioning and nanometer-level motion control, which limits the realization of ultra-high-resolution stepping motion of the turntable. At the same time, other angle measurement devices such as autocollimators and laser interferometers, although they can achieve high-resolution measurement within a small angle range, their angle generation capabilities within the full range of 0-360° still cannot meet the needs of certain specific application scenarios.

[0004] In summary, the existing technology urgently needs a turntable that can achieve high-resolution angle generation and adapt to various measurement and calibration requirements to solve the above technical bottlenecks. Summary of the invention

[0005] The technical problem to be solved by the present invention is the limitations of existing high-precision turntables in achieving ultra-high resolution angle generation. The purpose is to provide an ultra-high resolution turntable that can achieve stepping motion of no more than 0.001 arc second in the range of 0-360° to meet the needs of high-resolution angle generation.

[0006] The present invention is achieved through the following technical solutions:

[0007] An ultra-high resolution turntable, comprising:

[0008] An air-floating shaft system, comprising a bearing rotor and a bearing stator, wherein the bearing rotor is rotatably connected to the bearing stator;

[0009] A multi-reader grating feedback unit, which is connected to the air-floating shaft system and is used to collect the rotation angle signal of the bearing rotor;

[0010] A multi-reader signal processing unit, which is connected to the signal output end of the multi-reader grating feedback unit and is used to synchronously collect, subdivide and average the rotation angle signal output by the multi-reader grating feedback unit;

[0011] A ceramic motor unit, which is relatively fixed to the bearing stator and drives the bearing rotor to rotate;

[0012] A servo control unit is connected to the multi-reader signal processing unit and the ceramic motor unit, and is used to output a driving signal to the ceramic motor unit through closed-loop control based on signal feedback from the multi-reader signal processing unit.

[0013] Furthermore, the air-floating shaft system also includes: a workbench and a base, the workbench is fixedly connected to the bearing rotor, the bearing stator is fixedly connected to the base, an electrical interface is provided on the base, and the multi-reader signal processing unit and the servo control unit are both arranged in the base.

[0014] Specifically, the multi-reading head grating feedback unit includes: a circular grating, a reading head mounting disk and multiple reading heads, the circular grating is fixedly mounted on the bearing rotor, the reading head mounting disk is fixed on the bearing stator through a conversion tooling, the multiple reading heads are all mounted on the reading head mounting disk, and the multiple reading heads are evenly distributed along the circumferential direction of the circular grating.

[0015] Optionally, the central axis of the circular grating, the central axis of the workbench and the central axis of the bearing rotor coincide with each other.

[0016] Specifically, the ceramic motor unit comprises: a ceramic motor and a ceramic ring, wherein the ceramic ring is coaxially mounted on the bearing rotor, and the driving end of the ceramic motor rubs against the outer side surface of the ceramic ring through a preload force; the movement direction of the driving end of the ceramic motor does not coincide with the radius of the ceramic ring;

[0017] There are multiple ceramic motors, and the multiple ceramic motors are evenly distributed in the circumferential direction of the ceramic ring.

[0018] Optionally, the conversion relationship between the linear displacement of the ceramic motor and the angular displacement of the ceramic ring is: θ=360X / D, wherein X is the linear displacement of the ceramic motor, D is the outer diameter of the ceramic ring, and θ is the angular displacement of the ceramic ring.

[0019] Specifically, the multi-reader signal processing unit includes:

[0020] A signal synchronization acquisition module is used to synchronously acquire the original signals output by multiple reading heads through analog-to-digital conversion, and perform electronic subdivision processing on the original signals;

[0021] The signal real-time averaging module is used to read the signals of each reading head after electronic subdivision in real time and average the subdivision values ​​of multiple signals;

[0022] The signal real-time output module is used to output the angle average value calculated by the signal real-time averaging module to the servo control unit in the form of a differential ABZ encoder signal.

[0023] Specifically, the servo control unit includes:

[0024] A motion controller connected to the multi-reader signal processing unit, configured to receive an output signal of the multi-reader signal processing unit, calculate a control amount based on a closed-loop control algorithm, and generate a drive signal;

[0025] The ceramic motor driver is connected to the motion controller and the ceramic motor and is used for converting the driving signal output by the motion controller into a control signal for driving the ceramic motor.

[0026] Optionally, the motion controller includes two control modes:

[0027] Speed ​​mode: The motion controller outputs an analog voltage signal to the ceramic motor driver, and the ceramic motor driver adjusts the frequency and amplitude of the output sine wave signal in real time according to the size of the input voltage. The sine wave signal is transmitted to the ceramic motor, so that the ceramic motor reciprocates under the action of the sine wave signal, driving the bearing rotor to rotate rapidly;

[0028] Position mode: The motion controller adjusts the input voltage of the ceramic motor to position it at a specific position, and outputs a voltage command to the ceramic motor driver through a position closed-loop algorithm to drive the ceramic motor to perform angular positioning motion.

[0029] Optionally, the closed-loop control algorithm is: the closed-loop control algorithm is a PID control algorithm, with the output signal of the multi-reader signal processing unit as the angle feedback value, the target position set by the user as the expected angle value, and the control quantity is calculated by the PID control algorithm.

[0030] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0031] The multi-reader grating feedback unit in the present invention realizes high-precision feedback of angle signals through uniform distribution and signal acquisition of multiple read heads; the ceramic motor unit adopts a friction drive method and realizes angle conversion of nanometer-level linear displacement through uniform distribution of multiple ceramic motors; the servo control unit accurately controls the movement of the ceramic motor through a closed-loop control algorithm combined with real-time feedback of multi-reader signals, thereby realizing high-resolution angle generation of the turntable within the full range.

[0032] The present invention uses a multi-reader grating feedback unit to synchronously collect and average the angle signal in real time, thereby reducing electronic subdivision noise and improving the effective angular resolution of the grating; through the friction drive mode and uniform distribution design of the ceramic motor unit, the tilt error that may be caused by a single driving force is eliminated, thereby ensuring the smooth operation of the turntable; through the servo control unit combined with a closed-loop control algorithm, high-precision real-time adjustment of the ceramic motor can be achieved, thereby ensuring that the turntable achieves high-resolution stepping motion of no more than 0.001 arc second within the full range of 0-360°. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] The accompanying drawings illustrate exemplary embodiments of the present invention and, together with the description thereof, are used to explain the principles of the present invention. These drawings are included to provide a further understanding of the present invention, and the accompanying drawings are included in and constitute a part of this specification and do not constitute a limitation of the embodiments of the present invention.

[0034] Figure 1 It is a structural block diagram of an ultra-high resolution turntable according to the present invention.

[0035] Figure 2 It is a schematic structural diagram of an ultra-high resolution turntable according to the present invention.

[0036] Figure 3 It is a schematic diagram of the structure of the multi-reader grating feedback unit according to the present invention.

[0037] Figure 4 This is a structural block diagram of the multi-reader grating feedback unit according to the present invention.

[0038] Figure 5 is a schematic diagram of electronic subdivision according to the present invention.

[0039] Figure 6 It is a schematic diagram of the structure of the servo control unit according to the present invention.

[0040] Figure 7 It is a structural block diagram of the private server control unit according to the present invention.

[0041] Figure markings: 1-air-floating shaft system, 2-multi-reading head grating feedback unit, 3-multi-reading head signal processing unit, 4-ceramic motor unit, 5-servo control unit, 6-workbench, 7-digital head, 8-reading head mounting plate, 9-circular grating, 10-adapter, 11-bearing rotor, 12-ceramic ring, 13-ceramic motor, 14-bearing stator, 15-base, 16-electrical interface, 17-signal synchronization acquisition module, 18-signal real-time averaging module, 19-signal real-time output module, 20-motion controller, 21-ceramic motor driver. DETAILED DESCRIPTION

[0042] To make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and implementation methods. It is understood that the specific implementation methods described herein are only used to explain the relevant content, rather than to limit the present invention.

[0043] It should also be noted that, for the convenience of description, only the parts related to the present invention are shown in the drawings.

[0044] In the absence of conflict, the embodiments and features of the embodiments of the present invention may be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0045] Embodiment 1

[0046] like Figure 1 , Figure 2 , Figure 3 , Figure 4 , Figure 5 , Figure 6 and Figure 7 As shown, an ultra-high resolution turntable is provided. The technical solution of the ultra-high resolution turntable involves multiple modules working together to achieve high-resolution angle generation and measurement, including:

[0047] The air-floating shaft system 1 comprises a bearing rotor 11 and a bearing stator 14, wherein the bearing rotor 11 is rotationally connected to the bearing stator 14; the non-contact rotation connection between the bearing rotor 11 and the stator is achieved by air floating, which effectively reduces mechanical friction while ensuring rotation stability and high precision.

[0048] The multi-reading head grating feedback unit 2 is connected to the air-floating shaft system 1 and is used to collect the rotation angle signal of the bearing rotor 11; through the design of multiple reading heads 7 evenly distributed around the circular grating 9, the single-point collection error is reduced and more accurate angle feedback is provided.

[0049] The multi-reader signal processing unit 3 is connected to the signal output end of the multi-reader grating feedback unit 2, and is used to synchronously collect, subdivide and average the rotation angle signal output by the multi-reader grating feedback unit 2; it receives the original signal from the multi-reader grating feedback unit 2, performs synchronous collection and electronic subdivision processing, and converts the analog signal into a high-precision digital signal.

[0050] The ceramic motor unit 4 is relatively fixed to the bearing stator 14 and drives the bearing rotor 11 to rotate; a friction drive mode between the ceramic motor 13 and the ceramic ring 12 is adopted.

[0051] The servo control unit 5 is connected to the multi-reading head signal processing unit 3 and the ceramic motor unit 4, and is used to output a driving signal to the ceramic motor unit 4 through closed-loop control based on the signal feedback of the multi-reading head signal processing unit 3, and adjust the driving signal of the ceramic motor 13 in real time to ensure that the turntable can achieve precise angular stepping within the full range.

[0052] On the whole, the turntable provides low-friction rotation support through the air-floating shaft system 1, and combines with the multi-reader grating feedback unit 2 to collect the rotation angle signal in real time; then, the signal is synchronously collected and processed by the multi-reader signal processing unit 3 to improve the resolution; the ceramic motor unit 4 accurately controls the rotor rotation through friction drive; finally, the servo control unit 5 realizes precise control of the system according to the closed-loop feedback mechanism to ensure that the angular motion achieves ultra-high resolution.

[0053] Embodiment 2

[0054] like Figure 2 As shown, the air-floating shaft system 1 also includes: a workbench 6 and a base 15, the workbench 6 is fixedly connected to the bearing rotor 11, the bearing stator 14 is fixedly connected to the base 15, an electrical interface 16 is provided on the base 15, and the multi-reader signal processing unit 3 and the servo control unit 5 are both arranged in the base 15.

[0055] The workbench 6 is fixedly connected to the bearing rotor 11, and serves as a carrier of rotational motion, and is used to install the device to be tested or other measuring equipment. The base 15 is fixedly connected to the bearing stator 14, and provides structural support and stability for the entire air-floating shaft system 1. An electrical interface 16 is provided on the base 15, which is used for power supply and signal transmission, and provides support for the operation of the multi-reader signal processing unit 3 and the servo control unit 5. The multi-reader signal processing unit 3 and the servo control unit 5 are both integrated inside the base 15, and the overall structure is optimized through a compact design, reducing the system complexity and improving the system's anti-interference ability.

[0056] Embodiment 3

[0057] like Figure 2 , Figure 3 As shown, the multi-reading head grating feedback unit 2 includes: a circular grating 9, a reading head mounting plate 8 and a plurality of reading heads 7. The circular grating 9 is fixedly mounted on the bearing rotor 11. The reading head mounting plate 8 is fixed on the bearing stator 14 through the adapter tool 10. The plurality of reading heads 7 are all mounted on the reading head mounting plate 8, and the plurality of reading heads 7 are evenly distributed along the circumferential direction of the circular grating 9. The central axis of the circular grating 9, the central axis of the workbench 6 and the central axis of the bearing rotor 11 coincide.

[0058] The circular grating 9 is fixedly mounted on the bearing rotor 11 and is located on the side close to the workbench 6, so as to directly measure the rotation angle of the workbench 6. The central axis of the circular grating 9 coincides with the central axis of the workbench 6 and the bearing rotor 11, ensuring the axial alignment of the angle measurement, thereby avoiding measurement deviation caused by error factors such as the tilt of the bearing rotor 11.

[0059] Multiple reading heads 7 are installed on the reading head mounting plate 8 and are evenly distributed in the circumferential direction of the circular grating 9. Each reading head 7 can independently collect the rotation angle signal of the circular grating 9 and output a raw signal of ~1Vpp to provide a data basis for subsequent signal processing. The number of reading heads 7 is determined according to actual needs. Through the design of multiple reading heads 7, single-point signal interference is reduced and the accuracy and stability of the overall measurement are improved.

[0060] The circular grating 9 records the rotation angle information of the bearing rotor 11. Each reading head 7 extracts the rotation angle signal from the circular grating 9 by an independent optical reading method and outputs the signal in the form of ~1Vpp. The reading head mounting plate 8 ensures that multiple reading heads 7 are evenly distributed along the circumferential direction, thereby sharing the error of single-point measurement.

[0061] Embodiment 4

[0062] like Figure 2 and Figure 6 As shown, the ceramic motor unit 4 is a key driving component of the ultra-high resolution turntable. The ceramic motor unit 4 includes: a ceramic motor 13 and a ceramic ring 12. The ceramic ring 12 is coaxially mounted on the bearing rotor 11. The driving end of the ceramic motor 13 rubs against the outer side of the ceramic ring 12 through a preload force. There are multiple ceramic motors 13, and the multiple ceramic motors 13 are evenly distributed in the circumferential direction of the ceramic ring 12. The movement direction of the driving end of the ceramic motor 13 does not coincide with the radius of the ceramic ring 12. The reciprocating motion of the pusher claw of the ceramic motor 13 generates a tangential force on the ceramic ring 12, thereby driving the ceramic ring 12 to rotate.

[0063] The ceramic ring 12 is made of ceramic material and has a ring structure. It is coaxially mounted on the bearing rotor 11 and maintains a precise rotation transmission relationship with the bearing rotor 11. The designed outer diameter of the ceramic ring 12 directly affects the accuracy of the angular displacement, and its outer side surface provides a friction drive contact surface for the ceramic motor 13.

[0064] The ceramic motor 13 is a piezoelectric ceramic micro-motion device that can achieve nanometer-level linear displacement and is suitable for high-precision micro positioning. The ceramic motor 13 is in frictional contact with the outer side of the ceramic ring 12 through the preload force, and the ceramic ring 12 is driven to rotate by the friction force, converting the linear displacement into angular displacement. Multiple ceramic motors 13 are evenly distributed in the circumferential direction of the ceramic ring 12 to ensure the balance of the driving force and avoid the tilting of the air bearing or the degradation of the turntable performance caused by a single preload force.

[0065] The conversion relationship between the linear displacement of the ceramic motor 13 and the angular displacement of the ceramic ring 12 is: θ=360X / D, where X is the linear displacement of the ceramic motor 13, D is the outer diameter of the ceramic ring 12, and θ is the angular displacement of the ceramic ring 12. By properly designing the outer diameter of the ceramic ring 12, the nanometer-level linear displacement of the ceramic motor 13 can be converted into an angular motion better than 0.001 arc seconds, thereby meeting the requirements of ultra-high-resolution motion control.

[0066] Embodiment 5

[0067] like Figure 4 As shown, the multi-reader signal processing unit 3 includes:

[0068] The signal synchronous acquisition module 17 is used to synchronously acquire the original signals (~1Vpp) output by multiple reading heads 7 through analog-to-digital conversion, and perform electronic subdivision processing on the original signals; Figure 5 As shown, on the basis of synchronous acquisition, the signal of each reading head 7 is electronically subdivided to convert the analog signal into a digital signal with higher resolution.

[0069] The signal real-time averaging module 18 is used to read the signals of each reading head 7 after electronic segmentation in real time, and average the segmentation values ​​of multiple signals; the purpose of the average calculation is to eliminate the noise that may be introduced in the electronic segmentation process and reduce the uncertainty of the signal, thereby significantly improving the accuracy and stability of the angle feedback.

[0070] The signal real-time output module 19 is used to output the angle average value calculated by the signal real-time averaging module 18 to the servo control unit 5 in the form of a differential ABZ encoder signal. The differential ABZ encoder signal is a standard signal format widely used in high-precision control systems and can be directly transmitted to the servo control unit 5 for closed-loop feedback control.

[0071] Embodiment 6

[0072] like Figure 7 As shown, the control of the ultra-high resolution turntable is achieved through the servo control unit 5, and the servo control unit 5 includes:

[0073] The motion controller 20 is connected to the multi-reading head signal processing unit 3, and is used to receive the output signal of the multi-reading head signal processing unit 3, calculate the control quantity based on the closed-loop control algorithm, and generate a drive signal, that is, an analog voltage signal (±10V range).

[0074] The ceramic motor driver 21 is connected to the motion controller 20 and the ceramic motor 13, and is used to convert the driving signal output by the motion controller 20 into a control signal for driving the ceramic motor 13, thereby achieving precise driving of the ceramic motor 13 and supporting both position control and speed control modes.

[0075] Speed ​​mode: the motion controller 20 outputs an analog voltage signal to the ceramic motor driver 21. The ceramic motor driver 21 adjusts the frequency and amplitude of the output sine wave signal in real time according to the size of the input voltage. The sine wave signal is transmitted to the ceramic motor 13, so that the ceramic motor 13 performs reciprocating motion under the action of the sine wave signal, driving the bearing rotor 11 to rotate rapidly;

[0076] Position mode: The motion controller 20 adjusts the input voltage of the ceramic motor 13 to position it at a specific position, and outputs a voltage command to the ceramic motor driver 21 through a position closed-loop algorithm to drive the ceramic motor 13 to perform angular positioning movement.

[0077] The closed-loop control algorithm is usually a PID control algorithm, which uses the output signal of the multi-reader signal processing unit 3 as the angle feedback value and the target position set by the user as the angle expectation value, and calculates the control amount through the PID control algorithm. The motion controller 20 is a commercial controller, specifically the SPiiPLUS SC controller of ACS.

[0078] 1. Signal acquisition and feedback

[0079] The real-time angle feedback signal is obtained from the multi-reader signal processing unit 3. The signal is synchronously collected, subdivided and averaged, and has high resolution and low noise characteristics.

[0080] 2. Comparison between target value and feedback signal

[0081] The preset target angle value is compared with the real-time feedback signal to calculate the error signal.

[0082] 3. Calculation of control quantity (PID algorithm)

[0083] Based on the classic proportional-integral-derivative (PID) control method, the control quantity is calculated using the error signal.

[0084] 4.Signal output

[0085] The calculated control quantity is converted into an analog voltage signal (±10V range) and output to the ceramic motor driver 21.

[0086] 5. Closed-loop adjustment

[0087] The ceramic motor driver 21 drives the ceramic motor 13 according to the input voltage signal, and realizes motion control of the bearing rotor 11 through friction force.

[0088] During the movement, the feedback signal is monitored in real time and the control amount is adjusted dynamically to ensure that the error gradually converges and achieve stable control of the system.

[0089] In the description of this specification, the description with reference to the terms "one embodiment / method", "some embodiments / methods", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment / method or example are included in at least one embodiment / method or example of the present application. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment / method or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments / methods or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments / methods or examples described in this specification and the features of the different embodiments / methods or examples, unless they are contradictory.

[0090] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of this application, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0091] It should be understood by those skilled in the art that the above embodiments are only for the purpose of clearly illustrating the present invention, and are not intended to limit the scope of the present invention. For those skilled in the art, other changes or modifications may be made based on the above invention, and these changes or modifications are still within the scope of the present invention.

Claims

1. An ultra-high resolution turntable, characterized in that: include: An air-floating shaft system (1) comprises a bearing rotor (11) and a bearing stator (14), wherein the bearing rotor (11) is rotatably connected to the bearing stator (14); A multi-reader grating feedback unit (2), which is connected to the air-floating shaft system (1) and is used to collect the rotation angle signal of the bearing rotor (11); A multi-reader signal processing unit (3) connected to the signal output end of the multi-reader grating feedback unit (2) and used for synchronously collecting, subdividing and averaging the rotation angle signal output by the multi-reader grating feedback unit (2); A ceramic motor unit (4) which is fixed relative to the bearing stator (14) and drives the bearing rotor (11) to rotate; A servo control unit (5) is connected to the multi-reader signal processing unit (3) and the ceramic motor unit (4) and is used to output a drive signal to the ceramic motor unit (4) through closed-loop control based on signal feedback from the multi-reader signal processing unit (3).

2. The ultra-high resolution turntable according to claim 1, characterized in that: The air-floating shaft system (1) further comprises: a workbench (6) and a base (15); the workbench (6) is fixedly connected to the bearing rotor (11); the bearing stator (14) is fixedly connected to the base (15); and the multi-reader signal processing unit (3) and the servo control unit (5) are both arranged in the base (15).

3. The ultra-high resolution turntable according to claim 2, characterized in that: The multi-reading head grating feedback unit (2) comprises: a circular grating (9), a reading head mounting disk (8) and a plurality of reading heads (7), wherein the circular grating (9) is fixedly mounted on the bearing rotor (11), the reading head mounting disk (8) is fixed on the bearing stator (14) via a transfer fixture (10), the plurality of reading heads (7) are all mounted on the reading head mounting disk (8), and the plurality of reading heads (7) are evenly distributed along the circumferential direction of the circular grating (9).

4. The ultra-high resolution turntable according to claim 3, characterized in that: The central axis of the circular grating (9), the central axis of the workbench (6) and the central axis of the bearing rotor (11) coincide with each other.

5. The ultra-high resolution turntable according to claim 1, characterized in that: The ceramic motor unit (4) comprises: a ceramic motor (13) and a ceramic ring (12); the ceramic ring (12) is coaxially mounted on the bearing rotor (11); the driving end of the ceramic motor (13) rubs against the outer side surface of the ceramic ring (12) through a preload force; the movement direction of the driving end of the ceramic motor (13) does not coincide with the radius of the ceramic ring (12); The number of the ceramic motors (13) is multiple, and the multiple ceramic motors (13) are evenly distributed in the circumferential direction of the ceramic ring (12).

6. The ultra-high resolution turntable according to claim 5, characterized in that: The conversion relationship between the linear displacement of the ceramic motor (13) and the angular displacement of the ceramic ring (12) is: θ=360X / D, wherein X is the linear displacement of the ceramic motor (13), D is the outer diameter of the ceramic ring (12), and θ is the angular displacement of the ceramic ring (12).

7. The ultra-high resolution turntable according to claim 3, characterized in that: The multi-reader signal processing unit (3) comprises: A signal synchronization acquisition module (17) is used to synchronously acquire original signals of a plurality of reading heads (7) by analog-to-digital conversion, and to perform electronic subdivision processing on the original signals; A signal real-time averaging module (18) is used to read in real time the signals of each reading head (7) after electronic subdivision, and to perform average calculation on the subdivision values ​​of multiple signals; A signal real-time output module (19) is used to output the angle average value calculated by the signal real-time averaging module (18) to a servo control unit (5) in the form of a differential ABZ encoder signal.

8. The ultra-high resolution turntable according to claim 5, characterized in that: The servo control unit (5) comprises: A motion controller (20) connected to the multi-reader signal processing unit (3) and configured to receive an output signal of the multi-reader signal processing unit (3), calculate a control amount based on a closed-loop control algorithm, and generate a drive signal; A ceramic motor driver (21) is connected to the motion controller (20) and the ceramic motor (13) and is used to convert a drive signal output by the motion controller (20) into a control signal for driving the ceramic motor (13).

9. The ultra-high resolution turntable according to claim 8, characterized in that: The motion controller (20) includes two control modes: Speed ​​mode: the motion controller (20) outputs an analog voltage signal to the ceramic motor driver (21), and the ceramic motor driver (21) adjusts the frequency and amplitude of the output sine wave signal in real time according to the magnitude of the input voltage. The sine wave signal is transmitted to the ceramic motor (13), so that the ceramic motor (13) performs reciprocating motion under the action of the sine wave signal, thereby driving the bearing rotor (11) to rotate; Position mode: The motion controller (20) adjusts the input voltage of the ceramic motor (13) to position it at a specific position, and outputs a voltage command to the ceramic motor driver (21) through a position closed-loop algorithm to drive the ceramic motor (13) to perform angular positioning movement.

10. The ultra-high resolution turntable according to claim 9, characterized in that: The closed-loop control algorithm is: the closed-loop control algorithm is a PID control algorithm, which uses the output signal of the multi-reader signal processing unit (3) as the angle feedback value, and the target position set by the user as the angle expected value, and calculates the control amount through the PID control algorithm.

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