A precision turntable based on piezoelectric ceramics and its control method

Abstract

The present invention discloses a precision turntable based on piezoelectric ceramics and a control method. The turntable includes a worktable for mounting parts to be processed or inspected, and an upper support platform, a lower support platform, and a chassis disposed below the worktable. The lower support platform is mounted below the upper support platform and fixedly connected to the lower end of the upper support platform, and the chassis is fixedly mounted on the bottom of the lower support platform. The upper support platform is mounted and connected to an air-bearing spindle, which includes a spindle housing and a spindle rotor mounted within the spindle housing. The lower support platform is provided with a torque motor for driving the worktable to rotate and an angle adjustment platform for adjusting the positioning accuracy of the torque motor. Without improving the accuracy of existing torque motors, this device utilizes a composite structure of a torque motor and piezoelectric ceramics, utilizing the torque motor to achieve rapid and coarse positioning over a wide angle range, while the piezoelectric ceramic mechanism achieves precise and fine angle adjustment, enabling the turntable to achieve predetermined or higher precision and rapid positioning requirements.

Description

Technical Field

[0001] The present invention belongs to the field of rotary drive technology, and in particular relates to a precision turntable based on piezoelectric ceramics and a control method thereof. Background Art

[0002] Precision turntables are primarily rotational devices that integrate optical, mechanical, and electrical systems. They have important applications in instrumentation, optical inspection, aviation, and electronics. The positioning accuracy of a turntable is affected by a variety of factors, including motor accuracy, part machining accuracy, assembly accuracy, structural design, and the accuracy of angle measuring instruments. Using a rack and pinion or worm gear structure between the motor and the worktable can introduce disadvantages such as backlash, motion lag, and vibration. The positioning accuracy of traditional direct-drive turntables is limited by the accuracy of the torque motor itself and the internal encoder. Achieving higher accuracy is both costly and difficult. Summary of the Invention

[0003] The purpose of the present invention is to solve the problems existing in the above-mentioned prior art and to provide a precision turntable and control method based on piezoelectric ceramics. Without improving the accuracy of the existing torque motor, this device adopts a composite structure of a torque motor and piezoelectric ceramics, utilizes the torque motor to achieve rapid and coarse positioning of a large angle range, and the piezoelectric ceramic mechanism to achieve precise angle fine-tuning, so that the turntable can achieve the predetermined or higher precision and rapid positioning requirements.

[0004] To achieve the above-mentioned purpose, the present invention adopts the following technical solution: a precision turntable based on piezoelectric ceramics, comprising a workbench, the workbench is used to install parts to be processed or tested, and an upper support platform, a lower support platform and a chassis are arranged below the workbench; the lower support platform is installed below the upper support platform and is fixedly connected to the lower end of the upper support platform, and the bottom of the lower support platform is fixedly installed with a chassis; the upper support platform is installed and connected to an air-floating spindle, the air-floating spindle comprises a spindle housing and a spindle rotor installed in the spindle housing, wherein the spindle housing is installed in the upper support platform, and the upper end of the spindle rotor is fixedly connected to the workbench; a torque motor for driving the workbench to rotate and an angle adjustment platform for adjusting the positioning accuracy of the torque motor are arranged in the lower support platform.

[0005] To further improve this solution, measurement feedback components are provided at both ends of the spindle rotor, and the measurement feedback components include measurement component I and measurement component II, wherein measurement component I is arranged at the upper end of the spindle rotor, and measurement component I includes an upper circular grating and four upper reading heads distributed in the circumferential direction; measurement component II is arranged at the lower end of the spindle rotor, and measurement component II includes a lower circular grating and four lower reading heads distributed in the circumferential direction; the measurement feedback components are used to detect and provide feedback on the rotational positioning accuracy of the worktable.

[0006] To further improve this solution, the spindle housing is connected to the upper support platform, a top support frame is provided on the outside of the spindle housing, the top support frame is fixedly mounted on the upper support platform, and a top plate is connected to the upper end of the top support frame.

[0007] To further improve this solution, the torque motor includes a motor housing and a motor rotor, the motor rotor is fixedly connected to the motor drive shaft, the motor drive shaft extends into the upper support platform, and is connected to the lower end of the spindle rotor through an elastic coupling.

[0008] To further improve this solution, a chassis shaft is installed at the upper center end of the chassis, a deep groove ball bearing is installed on the chassis shaft, the inner ring of the deep groove ball bearing is installed on the chassis shaft, and the outer ring of the deep groove ball bearing supports the angle adjustment platform.

[0009] To further improve this solution, the motor drive shaft is connected to the elastic coupling via a second flat key, and the lower end of the main shaft rotor is connected to the elastic coupling via a first flat key.

[0010] To further improve this solution, the angle adjustment platform includes a piezoelectric ceramic rotating disk, a mounting hole cavity corresponding to the outer ring of the deep groove ball bearing is provided at the lower end of the piezoelectric ceramic rotating disk, the upper end surface of the piezoelectric ceramic rotating disk is fixedly connected to the motor housing, and a rotating arm extends outward from the edge of the piezoelectric ceramic rotating disk.

[0011] To further improve this solution, the angle adjustment platform also includes an angle control assembly installed on the chassis, the angle control assembly includes a first stop and a second stop arranged opposite to each other, the first stop and the second stop are both fixed on the chassis, the first stop is used to fix the piezoelectric ceramic, one side of the piezoelectric ceramic is fitted with the first stop, and the other side of the piezoelectric ceramic is in contact with the rotating arm, a group of inner holes are formed correspondingly on the adjacent sides of the second stop and the rotating arm, and the two ends of the compression spring are respectively embedded in the inner holes of the second stop and the rotating arm.

[0012] The present invention also provides a control method for a precision turntable, and the specific steps are as follows: a rotation positioning step: controlling the rotation of the motor rotor through an external motion controller to drive the worktable to rotate within a range of 360° to achieve rapid coarse positioning of the worktable; a measurement feedback step: detecting the rotation angle of the worktable through a measurement feedback component, comparing it with the required predetermined target position to obtain a feedback signal, and sending the feedback signal to the motion controller. The feedback signal obtained by the motion controller is calculated by a computer system to obtain the angle that needs to be corrected for the worktable; a control adjustment step: controlling the piezoelectric ceramic to extend or shorten the corresponding size according to the angle that needs to be corrected, so as to drive the motor housing and the piezoelectric ceramic rotating disk to rotate around the center of the chassis axis to adjust the corresponding angle, so that the worktable reaches the precise angle positioning requirement of the predetermined target position.

[0013] Beneficial effects

[0014] 1. The present invention improves the structure of the precision turntable through innovation, and adopts a composite structure of a torque motor and piezoelectric ceramics to enable the turntable to meet predetermined or higher precision and rapid positioning requirements. The specific analysis is as follows: an upper support platform and a lower support platform and their components are arranged under the workbench, and a torque motor and an angle adjustment platform for fine-tuning the torque motor are installed in the lower support platform; without improving the angle positioning accuracy of the existing torque motor, the motor rotor part realizes large-scale rapid coarse positioning of the turntable, and the piezoelectric ceramics utilize the piezoelectric effect to drive the motor housing to rotate through the piezoelectric ceramic rotating disk to achieve precise fine-tuning positioning of the turntable. At the same time, a high-precision measurement feedback component is used, and the double circular grating of the measurement feedback component is used to measure and feedback the rotation positioning accuracy of the workbench. This structure enables the workbench to quickly reach predetermined or higher angle positioning accuracy requirements by controlling the coordinated drive of the torque motor and piezoelectric ceramics.

[0015] 2. The present invention provides a control method for a precision turntable, employing separate macro-control and micro-control methods. Macro-control refers to the use of a motion controller to enable the torque motor to achieve flexible rotation of the turntable within a wide range of 360°. A dual-circular grating is used to measure the table's rotation angle and compare it with the desired target position to generate a feedback signal. Micro-control refers to the system calculating the feedback signal, controlling the piezoelectric ceramic to extend or contract to a corresponding dimension, and driving the torque motor and the worktable to rotate within a small angle range, thereby enabling the precision turntable to achieve the desired angular positioning requirement. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the embodiments of the invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0017] Figure 1 This is a front view of the precision turntable of the present invention;

[0018] Figure 2 for Figure 1 Cross-sectional view at the middle BB;

[0019] Figure 3 A top view of the precision turntable of the present invention;

[0020] Figure 4 for Figure 2 Cross-sectional view at DD in the middle;

[0021] Figure 5 for Figure 4 Cross-sectional view at EE;

[0022] Markings in the figure: 1. chassis, 2. lower support platform, 3. upper support platform, 4. lower reading head, 5. top support frame, 6. top plate, 7. upper reading head, 8. upper circular grating, 9. workbench, 10. upper reading head, 11. spindle rotor, 12. spindle housing, 13. lower circular grating, 14. lower reading head, 15. flat key 1, 16. elastic coupling, 17. flat key 2, 18. motor drive shaft, 19. motor rotor, 20. motor housing, 21. deep groove ball bearing, 22. chassis shaft, 23. first stopper, 24. piezoelectric ceramic, 25. piezoelectric ceramic rotating disk, 26. compression spring, 27. second stopper, 28. lower reading head, 29. lower reading head, 30. upper reading head, 31. upper reading head. DETAILED DESCRIPTION

[0023] In order to make the technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and embodiments.

[0024] As shown in the figure: This embodiment provides a precision turntable based on piezoelectric ceramics, including a workbench 9, which is used to install parts to be processed or tested, and an upper support platform 3, a lower support platform 2 and a chassis 1 are arranged below the workbench 9; the lower support platform 2 is installed below the upper support platform 3 and is fixedly connected to the lower end of the upper support platform 3, and the bottom of the lower support platform 2 is fixedly installed with a chassis 1; the upper support platform 3, the lower support platform 2 and the chassis 1 are connected by screws.

[0025] The upper support platform 3 is connected to the upper portion of the lower support platform 2. The upper support platform 3 is connected to the top support frame 5 and the top plate 6. The upper end of the upper support platform 3 is connected to an air-bearing spindle. The air-bearing spindle comprises a spindle housing 12 and a spindle rotor 11 within the spindle housing 12. The spindle housing 12 is mounted on the upper support platform 3 and secured by screws. A gap is formed between the outer circumference of the lower end of the spindle housing 12 and the inner wall of the upper support platform 3. The upper end of the spindle rotor 11 is fixedly connected to the workbench 9.

[0026] The upper end of the spindle housing 12 is connected to the upper support platform 3. A top support frame 5 is installed on the outside of the spindle housing 12. The top support frame 5 is fixed on the upper support platform 3 by screws. A top plate 6 is connected to the upper end of the top support frame 5 by screws.

[0027] Measurement feedback components are provided at the upper and lower ends of the spindle rotor 11. The measurement feedback components include measurement component I and measurement component II, wherein measurement component I is provided at the upper end of the spindle rotor 11 and measurement component II is provided at the lower end of the spindle rotor 11. The measurement feedback components are used to detect and provide feedback on the rotation positioning accuracy of the worktable 9. Measuring component I includes an upper circular grating 8 and four upper reading heads arranged around the outside of the upper circular grating 8, namely, upper reading head 7, upper reading head 10, upper reading head 30 and upper reading head 31. The upper circular grating 8 is fixedly mounted on the upper end of the spindle rotor 11 by screws. The four upper reading heads are mounted on the top plate 6 and are evenly distributed around the upper circular grating 8. The measuring component II includes a lower circular grating 13 and four lower reading heads arranged around the outside of the lower circular grating 13, namely, lower reading head 4, lower reading head 14, lower reading head 28 and lower reading head 29. The lower circular grating 13 is fixedly mounted on the lower end of the spindle rotor 11 by screws. Four evenly distributed mounting through holes are formed in the middle section of the circular wall of the upper support platform 3 in the circumferential direction corresponding to the lower circular grating 13. A lower reading head is correspondingly installed at each mounting through hole, and the upper reading head corresponds to the lower reading head in the upper and lower positions. Measuring assemblies I and II can be mounted at either the upper or lower end of the spindle rotor 11, or can be installed at intervals at either the upper or lower end, or at other locations, without limitation to the preferred embodiment of the present invention. A single reading head can be used, or multiple reading heads can be distributed circumferentially at a predetermined angle.

[0028] In this solution, both measurement components I and II are circular grating sensor assemblies, specifically comprising a scale grating and an indicator grating. The scale grating, or grating ring, is mounted on the rotor and rotates with the spindle rotor 11; the indicator grating is stationary and mounted within the readout head. The circular grating utilizes the moiré fringes of the scale grating and indicator grating to achieve non-contact angle measurement. The circular grating angle measurement system utilizes four readout heads evenly spaced around the circumference of the grating ring. The average of the readings from these four readout heads is taken as the angle measurement value, effectively minimizing the impact of grating ring eccentricity on angle measurement errors.

[0029] The lower support platform 2 is connected to the chassis 1. A torque motor and an angle adjustment platform for adjusting the positioning accuracy of the torque motor are installed in the lower support platform 2. The lower support platform 2 is installed below the upper support platform 3 and is fixedly connected to the lower end of the upper support platform 3. The chassis 1 is installed at the bottom of the lower support platform 2. The lower support platform 2 and the chassis 1 are fixedly connected by screws. The torque motor includes a motor housing 20 and a motor rotor 19. The motor rotor 19 is fixedly connected to the motor drive shaft 18. The motor drive shaft 18 is connected to the lower end of the main shaft rotor 11 through an elastic coupling 16. The motor drive shaft 18 is connected to the elastic coupling 16 through a flat key 2 17. The lower end of the main shaft rotor 11 is connected to the elastic coupling 16 through a flat key 15. The elastic coupling 16 is located inside the upper support platform 3. The elastic coupling 16 can allow the main shaft rotor 11 and the motor drive shaft 18 to have a certain eccentricity, but has rigidity in the circumferential direction. Because the center axis of the spindle rotor 11 is aligned with the center axis of the motor drive shaft 18 during assembly of the air-floating spindle, a certain eccentricity error is inevitable. The rigid coupling can only transmit torque. The elastic coupling has flexible parts in it. In addition to transmitting torque and motion, it can also compensate for various misalignment errors of the two connected shafts. Therefore, the elastic coupling 16 is selected for connection here.

[0030] A chassis shaft 22 is mounted at the center upper end of the chassis 1. It is connected to the chassis 1 via screws. A deep groove ball bearing 21 is mounted on the chassis shaft 22. The inner ring of the deep groove ball bearing 21 is mounted on the chassis shaft 22, and the outer ring of the deep groove ball bearing 21 is mounted on the angle adjustment platform. The chassis shaft 22 serves as a mounting and positioning mechanism for the deep groove ball bearing 21. The deep groove ball bearing 21 is designed to withstand both axial and radial forces. The deep groove ball bearing 21 supports the circular motion of the torque motor and can withstand both axial and radial forces transmitted by the piezoelectric ceramic rotating disk 25.

[0031] The angle adjustment platform includes a piezoelectric ceramic rotating disk 25. A mounting hole corresponding to a deep groove ball bearing 21 is machined into the lower end of the piezoelectric ceramic rotating disk 25. The deep groove ball bearing 21 is mounted in the hole. The piezoelectric ceramic rotating disk 25 is fixedly connected to the motor housing 20 by screws. The motor drive shaft 18 is connected to the motor rotor 19. The motor drive shaft 18 is connected to the spindle rotor 11 via an elastic coupling 16 to transmit rotational motion.

[0032] A rotating arm is provided around the circumference of the piezoelectric ceramic rotating disk 25. The angle adjustment platform further includes an angle control assembly disposed on the chassis 1. The angle control assembly comprises a first stopper 23 and a second stopper 27 disposed opposite each other. Both the first stopper 23 and the second stopper 27 are fixed to the upper end of the chassis 1. The first stopper 23 is used to secure the piezoelectric ceramic 24. One side of the piezoelectric ceramic 24 is fixedly connected to the first stopper 23, while the other side of the piezoelectric ceramic 24 contacts the rotating arm. A set of inner holes are formed on the adjacent sides of the second stopper 27 and the rotating arm, and the ends of the compression spring 26 are respectively embedded in the inner holes of the second stopper 27 and the rotating arm. The first and second stoppers 23 and 27 are L-shaped, each comprising a mounting arm and a vertical arm. The mounting arm is positioned within the mounting slot of the chassis 1. The vertical arm of the first stopper 23 is machined with a slot for mounting the piezoelectric ceramic 24. A block that mates with the slot is provided at the mounting end of the piezoelectric ceramic 24. A threaded hole is machined between the two blocks. The thrust side of the piezoelectric ceramic 24 is spherical. The slot of the first stopper 23 contains a screw hole for securing the piezoelectric ceramic 24. The piezoelectric ceramic 24 is mounted within the slot and secured with screws. The ball protrusion of the piezoelectric ceramic 24 contacts the rotating arm of the piezoelectric ceramic rotating disk 25. A counterweight is provided on the edge of the piezoelectric ceramic rotating disk 25 on the side corresponding to the rotating arm to ensure better balance during rotation adjustment of the piezoelectric ceramic rotating disk 25. The compression spring structure proposed in the present invention can be flexibly modified according to actual needs. For example, a tension spring can also be installed on one side of the piezoelectric ceramic, and is not limited to the embodiments described in the scheme.

[0033] When half of the piezoelectric ceramic 24's natural stroke is converted into angular displacement by the piezoelectric ceramic rotating disk 25, the angular displacement must be greater than the torque motor's positioning accuracy. This allows the piezoelectric ceramic 24 to conveniently and flexibly compensate for the angular displacement error generated by the torque motor within the specified angular travel range. The thrust-generating portion of the piezoelectric ceramic 24 has a spherical tip. Due to the piezoelectric ceramic 4's resistance to distortion, the spherical surface at the front of the piezoelectric ceramic 24 contacts the flat surface of the rotating arm of the piezoelectric ceramic rotating disk 25 to transmit thrust.

[0034] like Figure 4As shown, when the piezoelectric ceramic 24 is unpowered (i.e., in the zero position), the thrust generated by the compression spring 26 should be greater than the friction torque of the deep-groove ball bearing 21. When power is first applied, the piezoelectric ceramic 24 should travel a positive half of its intended travel toward the second stop 27 (i.e., in the Y direction). At this point, the piezoelectric ceramic 24 and the compression spring 26 stabilize the torque motor, preventing the motor housing 20 from rotating left or right as the motor rotor 19 rotates. After the torque motor has traveled its full travel, the piezoelectric ceramic 24 can expand or contract in either the positive or negative direction, and in conjunction with the compression spring 26, it controls the forward or reverse rotation of the motor housing 20, enabling the turntable to achieve the desired or higher positioning accuracy. The motor rotor 19 drives the spindle rotor 11 and part of the worktable 9 to achieve large-scale, rapid and rough positioning of the turntable. The piezoelectric ceramic rotating disk 25 bears the thrust of the piezoelectric ceramic 24 or the pressure of the compression spring 26 to rotationally drive the torque motor part. That is, the piezoelectric ceramic 24 drives the motor housing 20 part through the piezoelectric ceramic rotating disk 25 to achieve precise fine-tuning of the turntable, so that the turntable reaches the predetermined position or higher positioning accuracy requirements.

[0035] This solution also provides a control method for a precision turntable, and the specific steps are as follows: a rotation positioning step: controlling the rotation of the motor rotor 19 through the motion controller to drive the worktable 9 to rotate within a range of 360° to achieve rapid coarse positioning of the worktable 9; a measurement feedback step: using a measurement feedback component to detect the rotation angle of the worktable 9, comparing it with the required predetermined target position to obtain a feedback signal, and sending the feedback signal to the motion controller. The motion controller obtains the feedback signal and calculates the angle that needs to be corrected; a control adjustment step: controlling the piezoelectric ceramic 24 to extend or shorten the corresponding size according to the correction angle, so as to drive the motor housing 20 and the piezoelectric ceramic rotating disk 25 to rotate around the center of the chassis axis 22 to adjust the corresponding angle, so that the worktable 9 reaches the precise positioning requirement of the predetermined target position.

[0036] The control method utilizes separate control methods for coarse and fine positioning. The rotational positioning step utilizes a motion controller to enable the torque motor to achieve flexible rotation of the turntable within a wide 360° range. In the measurement feedback component, a dual-circular grating measures the rotation angle of the worktable 9 and compares it with the desired target position to generate a feedback signal. This dual-circular grating forms the feedback link for real-time online measurement of the angular position of the worktable 9. The computational control step utilizes the feedback signal to control the piezoelectric ceramic 24 to extend or contract by a corresponding amount, driving the torque motor and the overall worktable 9 to rotate within a narrow angular range. This corrects the angular positioning error generated by the turntable, allowing the precision turntable to achieve the desired angular position.

[0037] The above description is merely a preferred embodiment of the present invention and does not constitute any form of limitation to the present invention. Although the present invention has been disclosed as a preferred embodiment, it is not intended to limit the present invention. Any technician familiar with the present profession can make some changes or modifications to equivalent embodiments of equivalent changes using the technical contents disclosed above without departing from the scope of the technical solution of the present invention. However, any simple modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention are still within the scope of the technical solution of the present invention.

Claims

1. A precision turntable based on piezoelectric ceramics, characterized by: The invention comprises a workbench (9), wherein the workbench (9) is used for mounting parts to be processed or inspected, and an upper support platform (3), a lower support platform (2) and a chassis (1) are arranged below the workbench (9); the lower support platform (2) is mounted below the upper support platform (3) and is fixedly connected to the lower end of the upper support platform (3), and the chassis (1) is fixedly mounted on the bottom of the lower support platform (2); the upper support platform (3) is mounted and connected with an air-floating spindle, and the air-floating spindle comprises a spindle housing (12) and a spindle rotor (11) mounted in the spindle housing (12), wherein the spindle housing ( 12) is installed in the upper support platform (3), and the upper end of the spindle rotor (11) is fixedly connected to the workbench (9); a torque motor for driving the workbench (9) to rotate and an angle adjustment platform for adjusting the positioning accuracy of the torque motor are provided in the lower support platform (2); the torque motor includes a motor housing (20) and a motor rotor (19), and the motor rotor (19) is fixedly connected to the motor transmission shaft (18), and the motor transmission shaft (18) extends into the upper support platform (3) and is connected to the lower end of the spindle rotor (11) through an elastic coupling (16); The angle adjustment platform includes a piezoelectric ceramic rotating disk (25) and an angle control component mounted on a chassis (1); a mounting hole cavity corresponding to the outer ring of a deep groove ball bearing (21) is provided at the lower end of the piezoelectric ceramic rotating disk (25); an upper end surface of the piezoelectric ceramic rotating disk (25) is fixedly connected to the motor housing (20); and a rotating arm extends outward from the edge of the piezoelectric ceramic rotating disk (25); The angle control component includes a first stopper (23) and a second stopper (27) that are arranged opposite to each other. The first stopper (23) and the second stopper (27) are both fixed on the chassis (1). The first stopper (23) is used to fix the piezoelectric ceramic (24). One side of the piezoelectric ceramic (24) is fitted with the first stopper (23). The spherical surface on the other side of the piezoelectric ceramic (24) contacts the plane of the rotating arm of the piezoelectric ceramic rotating disk (25). A group of inner holes are correspondingly formed on the adjacent sides of the second stopper (27) and the rotating arm, and the two ends of the compression spring (26) are respectively embedded in the inner holes of the second stopper (27) and the rotating arm.

2. The piezoelectric ceramic-based precision turntable according to claim 1, characterized in that: Both ends of the spindle rotor (11) are provided with measurement feedback components, which include measurement component I and measurement component II, wherein measurement component I is provided at the upper end of the spindle rotor (11), and measurement component I includes an upper circular grating (8) and four upper reading heads (7, 10, 30, 31) distributed in the circumferential direction; measurement component II is provided at the lower end of the spindle rotor (11), and measurement component II includes a lower circular grating (13) and four lower reading heads (4, 14, 28, 29) distributed in the circumferential direction; the measurement feedback components are used to detect and provide feedback on the rotation positioning accuracy of the workbench (9).

3. The piezoelectric ceramic-based precision turntable according to claim 1, characterized in that: The spindle housing (12) is connected to the upper support platform (3), and a top support frame (5) is provided on the outer side of the spindle housing (12). The top support frame (5) is fixedly mounted on the upper support platform (3), and a top plate (6) is connected to the upper end of the top support frame (5).

4. The piezoelectric ceramic-based precision turntable according to claim 1, characterized in that: A chassis shaft (22) is installed at the center upper end of the chassis (1), a deep groove ball bearing (21) is installed on the chassis shaft (22), the inner ring of the deep groove ball bearing (21) is installed on the chassis shaft (22), and the outer ring of the deep groove ball bearing (21) supports the angle adjustment platform.

5. The piezoelectric ceramic-based precision turntable according to claim 1, characterized in that: The motor transmission shaft (18) is connected to the elastic coupling (16) via a second flat key (17), and the lower end of the main shaft rotor (11) is connected to the elastic coupling (16) via a first flat key (15).

6. A method for controlling a precision turntable, characterized by: The specific steps are as follows: Rotation positioning step: controlling the motor rotor (19) to rotate through an external motion controller, driving the workbench (9) to rotate within a range of 360 degrees, so as to achieve rapid coarse positioning of the workbench (9); Measuring feedback step: using a measuring feedback component to detect the rotation angle of the workbench (9), comparing it with the required predetermined target position to obtain a feedback signal, and sending the feedback signal to the motion controller. The feedback signal obtained by the motion controller is calculated by the computer system to obtain the angle of the workbench (9) that needs to be corrected; Control and adjustment steps: according to the angle to be corrected, the piezoelectric ceramic (24) is controlled to extend or shorten the corresponding size, so as to drive the motor housing (20) and the piezoelectric ceramic rotating disk (25) to rotate around the center of the chassis axis (22) to adjust the corresponding angle, and by driving the torque motor and the overall part of the workbench (9) to rotate within a small angle range, the angular positioning error generated by the turntable is corrected, so that the workbench (9) can achieve the precise angular positioning requirements of the predetermined target position.

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