Rotary platform based on sandwich type three-degree-of-freedom piezoelectric actuator and working method thereof
Through the rotation platform based on a sandwich three-degree of freedom piezoelectric actuator, the precision rotation platform is directly driven, which solves the problems of large size, low accuracy and poor impact resistance of multi-degree of freedom rotation platform in the prior art, and achieves high precision Lightweight design for positioning and multi-degree-of-freedom rotational motion.
Patent Information
- Application Number
- CN202411469180.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-10-21
- Publication Date
- 2025-02-25
AI Technical Summary
Under the requirements of high accuracy, the existing multi-degree-of-freedom rotating platform has problems such as large driving system volume, complex mechanical transmissions increase moment of inertia and mechanical friction, as well as low positioning accuracy, uneven pre-pressure and poor impact resistance.
Using a rotating platform based on a sandwich three-degree of freedom piezoelectric actuator, the precision rotating platform is directly driven through the combination of piezoelectric vibrator, rotor, centripetal joint bearing, housing and adjustment module to realize the rotation of three orthogonal directions. , and adjust the prepressure through the adjustment module.
It realizes high-precision positioning and multi-degree-of-freedom rotational motion, simplifies the mechanical system, reduces volume and weight, improves impact resistance and control accuracy.
Smart Images
Figure CN119519464A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of piezoelectric actuators, and in particular to a rotating platform based on a sandwich-type three-degree-of-freedom piezoelectric actuator and a working method thereof. Background Art
[0002] In the fields of precision rotating platforms and optical pointing systems, the existing driving mechanism mainly consists of multiple motors driving their respective rotation directions, and the multi-degree-of-freedom driving mechanism is formed through the series and parallel connection of the transmission mechanism. In the design of multi-degree-of-freedom rotating platforms with high precision requirements, a transmission mechanism and a reducer device are required. On the one hand, the drive system is bulky, and the complex mechanical transmission mechanism increases the rotational inertia and additional mechanical friction of the drive system. On the other hand, due to the transmission gap and processing and assembly errors, the control accuracy of the drive system is reduced. The existing three-degree-of-freedom piezoelectric actuator is a driver based on the inverse piezoelectric effect of piezoelectric materials, which has the advantages of high mechanical integration, multi-degree-of-freedom motion and high precision. However, the current multi-degree-of-freedom ultrasonic motor has difficulties in pre-stress application and coordination, and its size is large, making it difficult to achieve practical application. Even if a multi-stator structure or multiple springs are used to apply pre-stress, most of these ultrasonic motors still face problems such as low positioning accuracy, uneven pre-stress application, and poor impact resistance. Summary of the invention
[0003] The technical problem to be solved by the present invention is to provide a rotating platform based on a sandwich-type three-degree-of-freedom piezoelectric actuator and a working method thereof in view of the defects involved in the background technology.
[0004] The present invention adopts the following technical solutions to solve the above technical problems: A rotating platform based on a sandwich-type three-DOF piezoelectric actuator, comprising a piezoelectric vibrator, a rotor, a radial spherical bearing, a housing and an adjustment module; The piezoelectric vibrator comprises a driving prism, a fixing plate, and first to fourth driving columns; The driving prism is a regular quadrangular prism, the upper bottom surface area of which is smaller than the lower bottom surface area, and the lower bottom surface is provided with a first V-shaped groove and a second V-shaped groove; the first V-shaped groove and the second V-shaped groove are perpendicular to each other at the center of the lower bottom surface, dividing the lower bottom surface of the driving prism into first to fourth squares of the same shape; The fixing plate is provided with first to fourth fixing through holes corresponding to the first to fourth driving columns one by one; The first to fourth driving columns have the same structure, and all include a front beam, a rear beam, a locking bolt, a first piezoelectric ceramic sheet, and a second piezoelectric ceramic sheet; The front beam and the rear beam are both columns with the same cross-sectional shape as the first square, a threaded blind hole matching the locking bolt is provided at the center of the lower end surface of the front beam, and a through hole for the locking bolt to pass through is provided along the axis of the rear beam; The first piezoelectric ceramic sheet and the second piezoelectric ceramic sheet are both in the same shape as the first square, and are both provided with a through hole in the center for the locking bolt to pass through. They are both polarized along the thick bottom direction and stacked up and down. The polarization direction of the first piezoelectric ceramic sheet is from top to bottom, and the polarization direction of the second piezoelectric ceramic sheet is from bottom to top. The stud of the locking bolt passes through the fixed through hole corresponding to the driving column on the fixing plate, the rear beam, the second piezoelectric ceramic sheet, the first piezoelectric ceramic sheet, and then is threadedly connected to the threaded blind hole on the front beam, so as to tighten the rear beam, the second piezoelectric ceramic sheet, and the first piezoelectric ceramic sheet between the fixing plate and the front beam; The first to fourth squares of the lower bottom surface of the driving prism are respectively fixedly connected to the upper end surfaces of the front beams of the first to fourth driving columns in a one-to-one correspondence; The housing is a hollow regular prism or a hollow cylinder, and a first blind hole for cooperating with the radial spherical plain bearing is provided at the center of the upper end surface, and a through hole for accommodating the inner ring of the radial spherical plain bearing is provided at the center of the first blind hole; The piezoelectric vibrator is arranged in the shell, the fixing plate is fixed on the lower end surface of the shell, and the driving prism and the shell are coaxial; The rotor comprises an output shaft, a connecting column and a driving spherical segment, wherein the connecting column is cylindrical, the driving spherical segment is spherical segment, and the radius of the bottom surface of the driving spherical segment is greater than the radius of the lower end surface of the connecting column; the upper end surface of the connecting column is coaxially fixedly connected to one end of the output shaft, and the lower end surface is coaxially fixedly connected to the bottom surface of the driving spherical segment; The outer ring of the radial spherical bearing and the first blind hole on the upper end surface of the housing are clearance-matched and can slide freely up and down relative to the housing. The inner ring of the radial spherical bearing and the connecting column of the rotor are coaxially fixedly connected, so that the driving spherical segment of the rotor is located in the housing and abuts against the upper end surface of the driving prism, one end of the output shaft of the rotor extends out of the housing, and the center of the driving spherical segment coincides with the axis of the radial spherical bearing; The adjustment module comprises a connecting tube, an adjustment end cover and a disc spring; The connecting tube is a hollow cylinder with openings at both ends, which is sleeved outside the radial spherical bearing, and the lower end is coaxially fixedly connected to the upper end surface of the shell; the outer wall of the connecting tube is provided with an external thread; The regulating end cover is cylindrical, and the center of its lower end surface is provided with a threaded blind hole for matching with the thread on the outer wall of the connecting tube, and the center of the threaded blind hole is provided with a through hole through which the rotor output shaft extends; The disc spring is arranged between the adjustment end cover and the radial spherical bearing, one end of the disc spring abuts against the outer ring of the radial spherical bearing, and the other end abuts against the bottom surface of the threaded blind hole; The adjusting end cover is threadedly connected to the connecting tube and is used for adjusting the pre-pressure between the driving ball segment and the driving prism through the disc spring.
[0005] As a further optimization solution of the rotating platform based on the sandwich-type three-degree-of-freedom piezoelectric actuator of the present invention, the fixing plate is further provided with fifth to eighth fixing through holes for fixing to the lower end surface of the shell; The first to fourth fixed through holes are located on the first circular ring, the fifth to eighth fixed through holes are located on the second circular ring and are evenly distributed, the centers of the first circular ring and the second circular ring coincide, the fifth fixed pupil is located between the first and second fixed through holes, and the distances between the fifth fixed through hole and the first and second fixed through holes are equal.
[0006] In the present invention, the upper end surface of the driving prism is the driving foot.
[0007] The present invention also discloses a working method of the rotating platform based on the sandwich-type three-degree-of-freedom piezoelectric actuator, comprising the following steps: The center of gravity of the piezoelectric vibrator is taken as the origin of the Cartesian coordinate system, the axis passing through the origin and parallel to the straight line where the centers of the first and second fixing through holes are located is the X-axis, the axis passing through the origin and parallel to the straight line where the centers of the first and fourth fixing through holes are located is the Y-axis, and the axis of the housing is the Z-axis; If the rotor needs to rotate positively around the X axis: Applying a first excitation signal to the first piezoelectric ceramic pieces of the first and second driving columns, applying a second excitation signal to the first piezoelectric ceramic pieces of the third and fourth driving columns, and applying a third excitation signal to the second piezoelectric ceramic pieces of the first to fourth driving columns; or applying a first excitation signal to the second piezoelectric ceramic pieces of the first and second driving columns, applying a second excitation signal to the second piezoelectric ceramic pieces of the third and fourth driving columns, and applying a third excitation signal to the first piezoelectric ceramic pieces of the first to fourth driving columns; The first to third excitation signals are all AC harmonic signals with the same frequency and amplitude; the first excitation signal leads the third excitation signal by π / 2 in time phase difference, and the first excitation signal is opposite in phase to the second excitation signal; If the rotor needs to rotate in the opposite direction around the X-axis, the phase of the third excitation signal can be reversed; If the rotor needs to rotate positively around the Y axis: Applying a first excitation signal to the first piezoelectric ceramic pieces of the first and fourth driving columns, applying a second excitation signal to the first piezoelectric ceramic pieces of the second and third driving columns, and applying a third excitation signal to the second piezoelectric ceramic pieces of the first to fourth driving columns; or applying a first excitation signal to the second piezoelectric ceramic pieces of the first and second driving columns, applying a second excitation signal to the second piezoelectric ceramic pieces of the third and fourth driving columns, and applying a third excitation signal to the first piezoelectric ceramic pieces of the first to fourth driving columns; If the rotor needs to rotate in the opposite direction around the Y axis, the phase of the third excitation signal can be reversed; If you need the rotor to rotate around the Z axis: Applying a first excitation signal to the first piezoelectric ceramic pieces of the first and fourth driving columns, applying a second excitation signal to the first piezoelectric ceramic pieces of the second and third driving columns, applying a third excitation signal to the second piezoelectric ceramic pieces of the first and fourth driving columns, and applying a fourth excitation signal to the second piezoelectric ceramic pieces of the second and third driving columns; The fourth excitation signal and the first excitation signal are AC harmonic signals with the same frequency and amplitude, and the third excitation signal and the fourth excitation signal have opposite phases; If the rotor needs to rotate in the opposite direction around the Z axis, the first excitation signal can be changed to lag behind the third excitation signal by π / 2 in time phase difference.
[0008] Compared with the prior art, the present invention adopts the above technical solution and has the following technical effects: 1. The present invention uses a sandwich-type three-degree-of-freedom piezoelectric actuator to directly drive the precision rotating platform, replacing the traditional precision rotating platform composed of three rotating motors connected in series and parallel. It has no transmission mechanism and reducer, greatly simplifies the mechanical system, and is conducive to lightweight design; 2. It can achieve high-precision positioning and three-degree-of-freedom rotational motion, and is widely used in fields such as space pointing mechanisms that require multi-dimensional drive, optical target tracking, and robot joint technology. BRIEF DESCRIPTION OF THE DRAWINGS
[0009] Figure 1 It is a cross-sectional structural schematic diagram of the present invention; Figure 2 It is a schematic diagram of the structure of the piezoelectric vibrator in the present invention; Figure 3 It is a schematic diagram of the polarization direction of the first and second piezoelectric ceramic sheets in the first to fourth driving columns of the present invention; Figure 4 It is a schematic diagram of the structure of the rotor in the present invention; Figure 5 It is a schematic diagram comparing the bending vibration modes of the piezoelectric vibrator in the present invention in two X-axis directions with a phase difference of π; Figure 6 It is a schematic diagram comparing the bending vibration modes of the piezoelectric vibrator in the present invention in two Y-axis directions with a phase difference of π; Figure 7 It is a schematic diagram comparing the longitudinal vibration modes of the piezoelectric vibrator in the present invention at two phase differences of π; Figure 8 It is a schematic diagram of the working state of the piezoelectric vibrator when the rotor of the present invention rotates around the X-axis; Fig. 9 It is a schematic diagram of the working state of the piezoelectric vibrator when the rotor of the present invention rotates around the Y axis; Fig.10 It is a schematic diagram of the working state of the piezoelectric vibrator when the rotor of the present invention rotates around the Z axis.
[0010] In the figure, 1- piezoelectric vibrator, 2-rotor, 3-radial spherical bearing, 4-housing, 5-connecting tube, 6-adjusting end cover, 7-disc spring, 8-driving prism, 9-fixing plate, 10-rear beam of the first driving column, 11-second piezoelectric ceramic piece of the first driving column, 12-front beam of the second driving column, 13-first piezoelectric ceramic piece of the second driving column, 14-output shaft, 15-connecting column, 16-driving ball segment. DETAILED DESCRIPTION
[0011] The technical solution of the present invention is further described in detail below in conjunction with the accompanying drawings: The present invention can be implemented in many different forms and should not be considered to be limited to the embodiments described herein. On the contrary, these embodiments are provided to make this disclosure thorough and complete, and will fully express the scope of the present invention to those skilled in the art. In the accompanying drawings, components are enlarged for clarity.
[0012] It should be understood that although the terms first, second, third, etc. can be used here to describe various elements, components and / or parts, these elements, components and / or parts are not limited by these terms. These terms are only used to distinguish elements, components and / or parts from each other. Therefore, the first element, component and / or part discussed below can become the second element, component or part without departing from the teaching of the present invention.
[0013] like Figure 1 As shown, the present invention discloses a rotating platform based on a sandwich-type three-degree-of-freedom piezoelectric actuator, comprising a piezoelectric vibrator, a rotor, a radial spherical bearing, a housing and an adjustment module; like Figure 2 As shown, the piezoelectric vibrator comprises a driving prism, a fixing plate, and first to fourth driving columns; The driving prism is a regular quadrangular prism, the upper bottom surface area of which is smaller than the lower bottom surface area, and the lower bottom surface is provided with a first V-shaped groove and a second V-shaped groove; the first V-shaped groove and the second V-shaped groove are perpendicular to each other at the center of the lower bottom surface, dividing the lower bottom surface of the driving prism into first to fourth squares of the same shape; The fixing plate is provided with first to fourth fixing through holes corresponding to the first to fourth driving columns one by one; The first to fourth driving columns have the same structure, and all include a front beam, a rear beam, a locking bolt, a first piezoelectric ceramic sheet, and a second piezoelectric ceramic sheet; The front beam and the rear beam are both columns with the same cross-sectional shape as the first square, a threaded blind hole matching the locking bolt is provided at the center of the lower end surface of the front beam, and a through hole for the locking bolt to pass through is provided along the axis of the rear beam; The first piezoelectric ceramic sheet and the second piezoelectric ceramic sheet are both in the same shape as the first square, and are both provided with a through hole in the center for the locking bolt to pass through. They are both polarized along the thick bottom direction and stacked up and down. The polarization direction of the first piezoelectric ceramic sheet is from top to bottom, and the polarization direction of the second piezoelectric ceramic sheet is from bottom to top. Figure 3 As shown; The stud of the locking bolt passes through the fixed through hole corresponding to the driving column on the fixing plate, the rear beam, the second piezoelectric ceramic sheet, the first piezoelectric ceramic sheet, and then is threadedly connected to the threaded blind hole on the front beam, so as to tighten the rear beam, the second piezoelectric ceramic sheet, and the first piezoelectric ceramic sheet between the fixing plate and the front beam; The first to fourth squares of the lower bottom surface of the driving prism are respectively fixedly connected to the upper end surfaces of the front beams of the first to fourth driving columns in a one-to-one correspondence; The housing is a hollow regular prism or a hollow cylinder, and a first blind hole for cooperating with the radial spherical plain bearing is provided at the center of the upper end surface, and a through hole for accommodating the inner ring of the radial spherical plain bearing is provided at the center of the first blind hole; The piezoelectric vibrator is arranged in the shell, the fixing plate is fixed on the lower end surface of the shell, and the driving prism and the shell are coaxial; like Figure 4 As shown, the rotor comprises an output shaft, a connecting column and a driving spherical segment, wherein the connecting column is cylindrical, the driving spherical segment is spherical segment, and the radius of the bottom surface of the driving spherical segment is greater than the radius of the lower end surface of the connecting column; the upper end surface of the connecting column is coaxially fixedly connected to one end of the output shaft, and the lower end surface is coaxially fixedly connected to the bottom surface of the driving spherical segment; The outer ring of the radial spherical bearing and the first blind hole on the upper end surface of the housing are clearance-matched and can slide freely up and down relative to the housing. The inner ring of the radial spherical bearing and the connecting column of the rotor are coaxially fixedly connected, so that the driving spherical segment of the rotor is located in the housing and abuts against the upper end surface of the driving prism, one end of the output shaft of the rotor extends out of the housing, and the center of the driving spherical segment coincides with the axis of the radial spherical bearing; The adjustment module comprises a connecting tube, an adjustment end cover and a disc spring; The connecting tube is a hollow cylinder with openings at both ends, which is sleeved outside the radial spherical bearing, and the lower end is coaxially fixedly connected to the upper end surface of the shell; the outer wall of the connecting tube is provided with an external thread; The regulating end cover is cylindrical, and the center of its lower end surface is provided with a threaded blind hole for matching with the thread on the outer wall of the connecting tube, and the center of the threaded blind hole is provided with a through hole through which the rotor output shaft extends; The disc spring is arranged between the adjustment end cover and the radial spherical bearing, one end of the disc spring abuts against the outer ring of the radial spherical bearing, and the other end abuts against the bottom surface of the threaded blind hole; The adjusting end cover is threadedly connected to the connecting tube and is used for adjusting the pre-pressure between the driving ball segment and the driving prism through the disc spring.
[0014] The fixing plate is also provided with fifth to eighth fixing through holes for fixing to the lower end surface of the shell; The first to fourth fixed through holes are located on the first circular ring, the fifth to eighth fixed through holes are located on the second circular ring and are evenly distributed, the centers of the first circular ring and the second circular ring coincide, the fifth fixed pupil is located between the first and second fixed through holes, and the distances between the fifth fixed through hole and the first and second fixed through holes are equal.
[0015] The present invention also discloses a working method of the rotating platform based on the sandwich-type three-degree-of-freedom piezoelectric actuator, comprising the following steps: like Figure 3 As shown, the center of gravity of the piezoelectric vibrator is taken as the origin of the Cartesian coordinate system, the axis passing through the origin and parallel to the straight line where the centers of the first and second fixing through holes are located is the X-axis, the axis passing through the origin and parallel to the straight line where the centers of the first and fourth fixing through holes are located is the Y-axis, and the axis of the housing is the Z-axis; If the rotor needs to rotate positively around the X axis: Applying a first excitation signal to the first piezoelectric ceramic pieces of the first and second driving columns, applying a second excitation signal to the first piezoelectric ceramic pieces of the third and fourth driving columns, and applying a third excitation signal to the second piezoelectric ceramic pieces of the first to fourth driving columns; or applying a first excitation signal to the second piezoelectric ceramic pieces of the first and second driving columns, applying a second excitation signal to the second piezoelectric ceramic pieces of the third and fourth driving columns, and applying a third excitation signal to the first piezoelectric ceramic pieces of the first to fourth driving columns; Among them, the first to third excitation signals are all AC harmonic signals with the same frequency and amplitude; the first excitation signal leads the third excitation signal by π / 2 in time phase difference, and the first excitation signal is opposite in phase to the second excitation signal, so that the piezoelectric vibrator excites the longitudinal vibration mode and the bending vibration mode in the Y-axis direction at the same time, such as Figure 6 and Figure 7 As shown in the figure, through the coupling of the two vibration modes, a slight elliptical motion perpendicular to the X-axis is formed on the upper end surface of the piezoelectric vibrator, and the rotor is driven to rotate around the X-axis through friction, as shown in the figure. Figure 8 As shown; If the rotor needs to rotate in the opposite direction around the X-axis, the phase of the third excitation signal can be reversed; If the rotor needs to rotate positively around the Y axis: Applying a first excitation signal to the first piezoelectric ceramic pieces of the first and fourth driving columns, applying a second excitation signal to the first piezoelectric ceramic pieces of the second and third driving columns, and applying a third excitation signal to the second piezoelectric ceramic pieces of the first to fourth driving columns; or applying a first excitation signal to the second piezoelectric ceramic pieces of the first and second driving columns, applying a second excitation signal to the second piezoelectric ceramic pieces of the third and fourth driving columns, and applying a third excitation signal to the first piezoelectric ceramic pieces of the first to fourth driving columns; The piezoelectric vibrator is made to simultaneously excite the longitudinal vibration mode and the bending vibration mode in the X-axis direction, such as Figure 5 and Figure 7 As shown; through the coupling of the two vibration modes, a slight elliptical motion perpendicular to the Y axis is formed on the upper end surface of the piezoelectric vibrator, and the rotor is driven to rotate around the Y axis through friction, as shown Fig. 9 As shown; If the rotor needs to rotate in the opposite direction around the Y axis, the phase of the third excitation signal can be reversed; If you need the rotor to rotate around the Z axis: Applying a first excitation signal to the first piezoelectric ceramic pieces of the first and fourth driving columns, applying a second excitation signal to the first piezoelectric ceramic pieces of the second and third driving columns, applying a third excitation signal to the second piezoelectric ceramic pieces of the first and fourth driving columns, and applying a fourth excitation signal to the second piezoelectric ceramic pieces of the second and third driving columns; The fourth excitation signal and the first excitation signal are AC harmonic signals of the same frequency and amplitude. The third excitation signal and the fourth excitation signal have opposite phases, so that the piezoelectric vibrator excites the bending vibration mode in the X-axis direction and the bending vibration mode in the Y-axis direction at the same time. Figure 5 and Figure 6 As shown; through the coupling of the two vibration modes, a slight elliptical motion perpendicular to the Z axis is formed on the upper end surface of the piezoelectric vibrator, and the rotor is driven to rotate around the Z axis through friction, as shown Fig.10 As shown; If the rotor needs to rotate in the opposite direction around the Z axis, the first excitation signal can be changed to lag behind the third excitation signal by π / 2 in time phase difference.
[0016] The present invention adopts a sandwich-type three-degree-of-freedom piezoelectric actuator as a driver of the precision rotating platform, which can directly drive the precision rotating platform to realize rotation in three orthogonal directions, thereby increasing the positioning accuracy of the precision rotating platform and achieving lightweighting of the system.
[0017] It will be understood by those skilled in the art that, unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as generally understood by those skilled in the art in the art to which the present invention belongs. It should also be understood that terms such as those defined in common dictionaries should be understood to have meanings consistent with the meanings in the context of the prior art, and will not be interpreted with idealized or overly formal meanings unless defined as herein.
[0018] The specific implementation methods described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific implementation method of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.
Claims
1. A rotating platform based on a sandwich-type three-degree-of-freedom piezoelectric actuator, characterized in that: It includes a piezoelectric vibrator, a rotor, a radial spherical bearing, a housing and an adjustment module; The piezoelectric vibrator comprises a driving prism, a fixing plate, and first to fourth driving columns; The driving prism is a regular quadrangular prism, the upper bottom surface area of which is smaller than the lower bottom surface area, and the lower bottom surface is provided with a first V-shaped groove and a second V-shaped groove; the first V-shaped groove and the second V-shaped groove are perpendicular to each other at the center of the lower bottom surface, dividing the lower bottom surface of the driving prism into first to fourth squares of the same shape; The fixing plate is provided with first to fourth fixing through holes corresponding to the first to fourth driving columns one by one; The first to fourth driving columns have the same structure, and all include a front beam, a rear beam, a locking bolt, a first piezoelectric ceramic sheet, and a second piezoelectric ceramic sheet; The front beam and the rear beam are both columns with the same cross-sectional shape as the first square, a threaded blind hole matching the locking bolt is provided at the center of the lower end surface of the front beam, and a through hole for the locking bolt to pass through is provided along the axis of the rear beam; The first piezoelectric ceramic sheet and the second piezoelectric ceramic sheet are both in the same shape as the first square, and are both provided with a through hole in the center for the locking bolt to pass through. They are both polarized along the thick bottom direction and stacked up and down. The polarization direction of the first piezoelectric ceramic sheet is from top to bottom, and the polarization direction of the second piezoelectric ceramic sheet is from bottom to top. The stud of the locking bolt passes through the fixed through hole corresponding to the driving column on the fixing plate, the rear beam, the second piezoelectric ceramic sheet, the first piezoelectric ceramic sheet, and then is threadedly connected to the threaded blind hole on the front beam, so as to tighten the rear beam, the second piezoelectric ceramic sheet, and the first piezoelectric ceramic sheet between the fixing plate and the front beam; The first to fourth squares of the lower bottom surface of the driving prism are respectively fixedly connected to the upper end surfaces of the front beams of the first to fourth driving columns in a one-to-one correspondence; The housing is a hollow regular prism or a hollow cylinder, and a first blind hole for cooperating with the radial spherical plain bearing is provided at the center of the upper end surface, and a through hole for accommodating the inner ring of the radial spherical plain bearing is provided at the center of the first blind hole; The piezoelectric vibrator is arranged in the shell, the fixing plate is fixed on the lower end surface of the shell, and the driving prism and the shell are coaxial; The rotor comprises an output shaft, a connecting column and a driving spherical segment, wherein the connecting column is cylindrical, the driving spherical segment is spherical, and the radius of the bottom surface of the driving spherical segment is greater than the radius of the lower end surface of the connecting column; the upper end surface of the connecting column is coaxially fixedly connected to one end of the output shaft, and the lower end surface is coaxially fixedly connected to the bottom surface of the driving spherical segment; The outer ring of the radial spherical bearing and the first blind hole on the upper end surface of the housing are clearance-matched and can slide freely up and down relative to the housing. The inner ring of the radial spherical bearing and the connecting column of the rotor are coaxially fixedly connected, so that the driving spherical segment of the rotor is located in the housing and abuts against the upper end surface of the driving prism, one end of the output shaft of the rotor extends out of the housing, and the center of the driving spherical segment coincides with the axis of the radial spherical bearing; The adjustment module comprises a connecting tube, an adjustment end cover and a disc spring; The connecting tube is a hollow cylinder with openings at both ends, which is sleeved outside the radial spherical bearing, and the lower end is coaxially fixedly connected to the upper end surface of the shell; the outer wall of the connecting tube is provided with an external thread; The regulating end cover is cylindrical, and the center of its lower end surface is provided with a threaded blind hole for matching with the thread on the outer wall of the connecting tube, and the center of the threaded blind hole is provided with a through hole through which the rotor output shaft extends; The disc spring is arranged between the adjustment end cover and the radial spherical bearing, one end of the disc spring abuts against the outer ring of the radial spherical bearing, and the other end abuts against the bottom surface of the threaded blind hole; The adjusting end cover is threadedly connected to the connecting tube and is used for adjusting the pre-pressure between the driving ball segment and the driving prism through the disc spring.
2. The rotating platform based on the sandwich three-DOF piezoelectric actuator according to claim 1, characterized in that: The fixing plate is also provided with fifth to eighth fixing through holes for fixing to the lower end surface of the shell; The first to fourth fixed through holes are located on the first circular ring, the fifth to eighth fixed through holes are located on the second circular ring and are evenly distributed, the centers of the first circular ring and the second circular ring coincide, the fifth fixed pupil is located between the first and second fixed through holes, and the distances between the fifth fixed through hole and the first and second fixed through holes are equal.
3. The working method of the rotating platform based on the sandwich three-DOF piezoelectric actuator according to claim 1, characterized in that: The following steps are involved: The center of gravity of the piezoelectric vibrator is taken as the origin of the Cartesian coordinate system, the axis passing through the origin and parallel to the straight line where the centers of the first and second fixing through holes are located is the X-axis, the axis passing through the origin and parallel to the straight line where the centers of the first and fourth fixing through holes are located is the Y-axis, and the axis of the housing is the Z-axis; If the rotor needs to rotate positively around the X axis: Applying a first excitation signal to the first piezoelectric ceramic pieces of the first and second driving columns, applying a second excitation signal to the first piezoelectric ceramic pieces of the third and fourth driving columns, and applying a third excitation signal to the second piezoelectric ceramic pieces of the first to fourth driving columns; or applying a first excitation signal to the second piezoelectric ceramic pieces of the first and second driving columns, applying a second excitation signal to the second piezoelectric ceramic pieces of the third and fourth driving columns, and applying a third excitation signal to the first piezoelectric ceramic pieces of the first to fourth driving columns; The first to third excitation signals are all AC harmonic signals with the same frequency and amplitude; the first excitation signal leads the third excitation signal by π / 2 in time phase difference, and the first excitation signal is opposite in phase to the second excitation signal; If the rotor needs to rotate in the opposite direction around the X-axis, the phase of the third excitation signal can be reversed; If the rotor needs to rotate positively around the Y axis: Applying a first excitation signal to the first piezoelectric ceramic pieces of the first and fourth driving columns, applying a second excitation signal to the first piezoelectric ceramic pieces of the second and third driving columns, and applying a third excitation signal to the second piezoelectric ceramic pieces of the first to fourth driving columns; or applying a first excitation signal to the second piezoelectric ceramic pieces of the first and second driving columns, applying a second excitation signal to the second piezoelectric ceramic pieces of the third and fourth driving columns, and applying a third excitation signal to the first piezoelectric ceramic pieces of the first to fourth driving columns; If the rotor needs to rotate in the opposite direction around the Y axis, the phase of the third excitation signal can be reversed; If you need the rotor to rotate around the Z axis: Applying a first excitation signal to the first piezoelectric ceramic pieces of the first and fourth driving columns, applying a second excitation signal to the first piezoelectric ceramic pieces of the second and third driving columns, applying a third excitation signal to the second piezoelectric ceramic pieces of the first and fourth driving columns, and applying a fourth excitation signal to the second piezoelectric ceramic pieces of the second and third driving columns; The fourth excitation signal and the first excitation signal are AC harmonic signals with the same frequency and amplitude, and the third excitation signal and the fourth excitation signal have opposite phases; If the rotor needs to rotate in the opposite direction around the Z axis, the first excitation signal can be changed to lag behind the third excitation signal by π / 2 in time phase difference.