CN116191929A - Three-degree-of-freedom piezoelectric actuator and working method thereof - Google Patents
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- H—ELECTRICITY
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- H02N2/00—Electric machines in general using piezoelectric effect, electrostriction or magnetostriction
- H02N2/10—Electric machines in general using piezoelectric effect, electrostriction or magnetostriction producing rotary motion, e.g. rotary motors
- H02N2/108—Electric machines in general using piezoelectric effect, electrostriction or magnetostriction producing rotary motion, e.g. rotary motors around multiple axes of rotation, e.g. spherical rotor motors
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- H—ELECTRICITY
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- H—ELECTRICITY
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Abstract
The invention discloses a three-degree-of-freedom piezoelectric actuator and a working method thereof, wherein the piezoelectric actuator comprises a piezoelectric vibrator, a spherical rotor, a clamping frame and first to fourth connecting rods; the piezoelectric vibrator includes a stator and first to eighth piezoelectric ceramic plates. According to the invention, by applying a specific combined excitation signal to the first to eighth piezoelectric ceramic plates, two vibration modes of one radial bending vibration mode and two orthogonal axial bending vibration modes of the stator are excited, so that micro elliptical motion is formed on the driving surface of the stator by coupling, and the spherical rotor is driven by friction action to obtain rotation in three degrees of freedom. The invention can realize three-degree-of-freedom rotary motion, has the advantages of simple structure, power-off self-locking, easy miniaturization and the like, and is suitable for the fields of space pointing mechanisms, optical target tracking, robot joint technology and the like.
Description
Technical Field
The invention relates to the technical field of piezoelectric actuators, in particular to a three-degree-of-freedom piezoelectric actuator and a working method thereof.
Background
Along with the rapid development of the precise driving technology, higher requirements and limitations are imposed on the performance of an actuator in a driving system, and the actuator is required to realize multi-degree-of-freedom motion, rapid response, no electromagnetic interference, miniaturization and the like. The traditional multi-degree-of-freedom actuator mainly adopts a mode that a plurality of single-degree-of-freedom electromagnetic motors are connected in series to realize three-degree-of-freedom motion, a multi-degree-of-freedom spherical electromagnetic motor, a multi-degree-of-freedom space parallel mechanism and the like, and the structures are provided with complex transmission mechanisms, so that the volume is huge and the structure is complex. The multi-degree-of-freedom piezoelectric actuator is based on the inverse piezoelectric effect of piezoelectric materials to convert electric energy into mechanical energy, excites a stator to generate corresponding resonance modes, and realizes multi-degree-of-freedom movement of a rotor under the driving of friction.
Disclosure of Invention
The invention aims to solve the technical problem of providing a three-degree-of-freedom piezoelectric actuator and a working method thereof aiming at the defects related to the background technology.
The invention adopts the following technical scheme for solving the technical problems:
a three-degree-of-freedom piezoelectric actuator comprises a piezoelectric vibrator, a spherical rotor, a clamping frame and first to fourth connecting rods;
the piezoelectric vibrator includes a stator, and first to eighth piezoelectric ceramic pieces;
the stator is a hollow sphere table with two open ends, and is symmetrical about a neutral plane between two bottom surfaces;
the first to eighth piezoelectric ceramic plates have the same structure and are block spherical shells, and each block spherical shell comprises an outer wall, an inner wall and first to fourth side walls which are sequentially connected end to end, wherein the diameter of the inner wall is equal to the diameter of the outer spherical surface of the stator;
the first piezoelectric ceramic piece, the third piezoelectric ceramic piece, the fifth piezoelectric ceramic piece and the seventh piezoelectric ceramic piece are circumferentially and uniformly arranged on the outer spherical surface of the stator, the second piezoelectric ceramic piece, the fourth piezoelectric ceramic piece, the sixth piezoelectric ceramic piece and the seventh piezoelectric ceramic piece are circumferentially and uniformly arranged on the outer spherical surface of the stator, and the first piezoelectric ceramic piece, the second piezoelectric ceramic piece, the third piezoelectric ceramic piece, the fourth piezoelectric ceramic piece, the fifth piezoelectric ceramic piece, the sixth piezoelectric ceramic piece, the seventh piezoelectric ceramic piece and the eighth piezoelectric ceramic piece are symmetrical about a neutral plane between two bottom surfaces of the stator; the first side wall and the third side wall of the first piezoelectric ceramic plate to the eighth piezoelectric ceramic plate are parallel to the bottom surface of the stator, and the second side wall and the fourth side wall of the first piezoelectric ceramic plate to the eighth piezoelectric ceramic plate are coplanar with the axis of the stator; the first piezoelectric ceramic piece and the eighth piezoelectric ceramic piece are polarized along the thickness direction and the polarization direction is inward;
the spherical rotor adopts a sphere or a spherical table symmetrical about a neutral plane between two bottom surfaces, is arranged in the stator and is contacted with the spherical surface of the stator;
the clamping frame contains the stator; the first to fourth connecting rods are circumferentially and uniformly arranged outside the stator, one ends of the first to fourth connecting rods are fixedly connected with the junction of four pitch circles and the pitch diameter in a one-to-one correspondence mode in the working mode of the stator respectively, and the other ends of the first to fourth connecting rods are fixedly connected with the clamping frame.
As a further optimization scheme of the three-degree-of-freedom piezoelectric actuator, the clamping frame adopts a square frame, and threaded through holes for fixedly connecting with the outside are formed in four middle points of four sides of the square frame.
As a further optimization scheme of the three-degree-of-freedom piezoelectric actuator, one ends of the first connecting rod, the second connecting rod and the fourth connecting rod, which are close to the stator, are concave spherical surfaces matched with the stator.
As a further optimization scheme of the three-degree-of-freedom piezoelectric actuator, the spherical rotor adopts a spherical table symmetrical about a neutral plane between two bottom surfaces, and a circular through hole for arranging an output shaft is arranged along an axis.
The invention also discloses a working method of the three-degree-of-freedom piezoelectric actuator, which comprises the following steps:
the spherical center of the stator is a Cartesian coordinate system origin, the angular bisection plane of the plane where the second side wall and the fourth side wall of the first piezoelectric ceramic piece are located is a plane A, the angular bisection plane of the plane where the second side wall and the fourth side wall of the third piezoelectric ceramic piece are located is a plane B, the neutral plane between the two bottom surfaces of the stator is C, the direction outwards along the intersection line of the plane A and the plane C from the origin of coordinates is an X-axis orthogonal direction, the direction outwards along the intersection line of the plane B and the plane C from the origin of coordinates is a Y-axis orthogonal direction, and the direction from the origin of coordinates to the bottom surface of the stator close to the first piezoelectric ceramic piece along the axis of the stator is a Z-axis orthogonal direction;
if the spherical rotor needs to be driven to rotate around the X axis:
applying a first excitation signal to the first, second, fifth and sixth piezoelectric ceramic plates, applying a second excitation signal to the third and eighth piezoelectric ceramic plates, applying a third excitation signal to the fourth and seventh piezoelectric ceramic plates, wherein the first to third excitation signals are all same-frequency and same-amplitude alternating-current harmonic signals, the first excitation signal advances by pi/2 of the second excitation signal in time phase difference, and the second excitation signal is opposite to the third excitation signal in phase, so that the piezoelectric vibrator simultaneously excites a radial bending vibration mode and an axial bending vibration mode in the Y-axis direction; through the coupling of the radial bending vibration mode and the axial bending vibration mode in the Y-axis direction, a driving surface of the piezoelectric vibrator forms a micro elliptical motion perpendicular to the X-axis, and the spherical rotor is driven to rotate around the X-axis through friction;
if the first excitation signal needs to reversely rotate around the X axis, the phase of the first excitation signal is inverted;
if the spherical rotor needs to be driven to rotate around the Y axis:
applying a first excitation signal to the third, fourth, seventh and eighth piezoelectric ceramic plates, applying a second excitation signal to the first and sixth piezoelectric ceramic plates, applying a third excitation signal to the second and fifth piezoelectric ceramic plates, wherein the first to third excitation signals are all same-frequency and same-amplitude alternating-current harmonic signals, the first excitation signal advances by pi/2 of the second excitation signal in time phase difference, and the second excitation signal is opposite to the third excitation signal in phase, so that the piezoelectric vibrator simultaneously excites a radial bending vibration mode and an axial bending vibration mode in the X-axis direction; through the coupling of the radial bending vibration mode and the axial bending vibration mode in the X-axis direction, the micro elliptical motion perpendicular to the Y-axis is formed on the driving surface of the piezoelectric vibrator, and the spherical rotor is driven to rotate around the Y-axis through friction;
if the first excitation signal needs to reversely rotate around the Y axis, the phase of the first excitation signal is inverted;
if the spherical rotor needs to be driven to rotate around the Z axis:
applying a fourth excitation signal to the first piezoelectric ceramic plate and the sixth piezoelectric ceramic plate, applying a fifth excitation signal to the second piezoelectric ceramic plate and the fifth piezoelectric ceramic plate, applying a sixth excitation signal to the third piezoelectric ceramic plate and the eighth piezoelectric ceramic plate, applying a seventh excitation signal to the fourth piezoelectric ceramic plate and the seventh piezoelectric ceramic plate, wherein the first excitation signal to the seventh excitation signal are all alternating-current harmonic signals with the same frequency and the same amplitude, the fourth excitation signal leads the sixth excitation signal pi/2 in time phase difference, the fourth excitation signal is opposite to the phase of the sixth excitation signal, the phase of the fifth excitation signal is opposite to the phase of the seventh excitation signal, and the piezoelectric vibrator simultaneously has two orthogonal axial bending vibration modes; through the coupling of two orthogonal axial bending vibration modes, a micro elliptical motion perpendicular to a Z axis is formed on a driving surface of the piezoelectric vibrator, and the spherical rotor is driven to rotate around the Z axis through friction;
if a reverse rotation around the Z axis is required, the fourth excitation signal is changed to lag the sixth excitation signal pi/2 in time phase difference.
Compared with the prior art, the technical scheme provided by the invention has the following technical effects:
1. the piezoelectric ceramic piece is stuck to the outer spherical surface of the stator by adopting a patch type structure, so that the structure of the piezoelectric vibrator can be simplified, and the size of the actuator can be effectively reduced;
2. the adoption of the spherical contact between the stator and the spherical rotor is beneficial to increasing the driving surface and improving the efficiency of the actuator.
Drawings
FIG. 1 is a schematic diagram of the structure of the present invention;
fig. 2 is a schematic structural view of a piezoelectric vibrator according to the present invention;
FIG. 3 is a schematic view showing the polarization directions of the first to eighth piezoelectric ceramic plates according to the present invention;
FIG. 4 is a schematic view of the structure of the spherical rotor of the present invention;
FIG. 5 is a schematic view of the structure of the clamping frame and the first to fourth connecting rods according to the present invention;
FIG. 6 is a diagram showing the contrast of two radial flexural vibration modes of a piezoelectric vibrator having a phase difference of 180 degrees in an XOY plane according to the present invention
FIG. 7 is a schematic diagram showing a contrast of axial flexural vibration modes of a piezoelectric vibrator in the Y-axis direction with a phase difference of 180 degrees on an XOZ plane;
FIG. 8 is a schematic diagram showing a mode contrast of axial flexural vibration modes of a piezoelectric vibrator in an X-axis direction with a phase difference of 180 degrees on an XOZ plane;
FIG. 9 is a schematic view showing the operation state of the piezoelectric vibrator when the present invention rotates around the X-axis;
FIG. 10 is a schematic view showing the operation state of the piezoelectric vibrator when the present invention rotates around the Y-axis;
fig. 11 is a schematic view showing an operation state of the piezoelectric vibrator when the present invention rotates around the X-axis.
In the figure, a 1-piezoelectric vibrator, a 2-spherical rotor, a 3-clamping frame, a 4-stator, a 5-fifth piezoelectric ceramic plate, a circular through hole on the 6-spherical rotor, a 7-rectangular square frame, an 8-first connecting rod and a threaded through hole on the 9-clamping frame.
Description of the embodiments
The technical scheme of the invention is further described in detail below with reference to the accompanying drawings:
this invention may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. In the drawings, the components are exaggerated for clarity.
It will be understood that, although the terms first, second, third, etc. may be used herein to describe various elements, components and/or sections, these elements, components and/or sections should not be limited by these terms. These terms are only used to distinguish one element, component, and/or section from another. Accordingly, a first element, component, and/or section discussed below could be termed a second element, component, or section without departing from the teachings of the present invention.
As shown in fig. 1, the invention discloses a three-degree-of-freedom piezoelectric actuator, which comprises a piezoelectric vibrator, a spherical rotor, a clamping frame and first to fourth connecting rods;
as shown in fig. 2, the piezoelectric vibrator includes a stator, and first to eighth piezoelectric ceramic pieces;
the stator is a hollow sphere table with two open ends, and is symmetrical about a neutral plane between two bottom surfaces;
the first to eighth piezoelectric ceramic plates have the same structure and are block spherical shells, and each block spherical shell comprises an outer wall, an inner wall and first to fourth side walls which are sequentially connected end to end, wherein the diameter of the inner wall is equal to the diameter of the outer spherical surface of the stator;
the first piezoelectric ceramic piece, the third piezoelectric ceramic piece, the fifth piezoelectric ceramic piece and the seventh piezoelectric ceramic piece are circumferentially and uniformly arranged on the outer spherical surface of the stator, the second piezoelectric ceramic piece, the fourth piezoelectric ceramic piece, the sixth piezoelectric ceramic piece and the seventh piezoelectric ceramic piece are circumferentially and uniformly arranged on the outer spherical surface of the stator, and the first piezoelectric ceramic piece, the second piezoelectric ceramic piece, the third piezoelectric ceramic piece, the fourth piezoelectric ceramic piece, the fifth piezoelectric ceramic piece, the sixth piezoelectric ceramic piece, the seventh piezoelectric ceramic piece and the eighth piezoelectric ceramic piece are symmetrical about a neutral plane between two bottom surfaces of the stator; the first side wall and the third side wall of the first piezoelectric ceramic plate to the eighth piezoelectric ceramic plate are parallel to the bottom surface of the stator, and the second side wall and the fourth side wall of the first piezoelectric ceramic plate to the eighth piezoelectric ceramic plate are coplanar with the axis of the stator; the first to eighth piezoelectric ceramic plates are polarized in the thickness direction and the polarization direction is inward as shown in fig. 3;
the spherical rotor adopts a sphere or a spherical table symmetrical about a neutral plane between two bottom surfaces, is arranged in the stator and is contacted with the spherical surface of the stator;
the clamping frame contains the stator; the first to fourth connecting rods are circumferentially and uniformly arranged outside the stator, one ends of the first to fourth connecting rods are fixedly connected with the junction of four pitch circles and the pitch diameter in a one-to-one correspondence mode in the working mode of the stator respectively, and the other ends of the first to fourth connecting rods are fixedly connected with the clamping frame.
As shown in fig. 4, when the spherical rotor employs a spherical table symmetrical about a neutral plane between two bottom surfaces, it is provided with a circular through hole along an axis for providing an output shaft.
As shown in fig. 5, when the square frame is adopted as the clamping frame, threaded through holes for fixedly connecting with the outside are formed at the four middle points of the four sides of the square frame.
One ends of the first connecting rod, the second connecting rod and the fourth connecting rod, which are close to the stator, are concave spherical surfaces matched with the stator.
The first to fourth connecting rods are fixedly connected with the outer spherical surface of the stator, and the connecting positions are positioned at the junction of the pitch circle and the pitch diameter of the working mode of the stator, namely four points of the outer spherical surface of the stator, through which two straight lines forming an included angle of 45 degrees and-45 degrees with the X axis pass in the XOY plane of the stator.
The larger the height of the spherical rotor, the larger the rotatable angle range, and the largest rotatable angle range when the spherical body is adopted.
The invention also discloses a working method of the three-degree-of-freedom piezoelectric actuator, which comprises the following steps:
the spherical center of the stator is a Cartesian coordinate system origin, the angular bisection plane of the plane where the second side wall and the fourth side wall of the first piezoelectric ceramic piece are located is a plane A, the angular bisection plane of the plane where the second side wall and the fourth side wall of the third piezoelectric ceramic piece are located is a plane B, the neutral plane between the two bottom surfaces of the stator is C, the direction outwards along the intersection line of the plane A and the plane C from the origin of coordinates is an X-axis orthogonal direction, the direction outwards along the intersection line of the plane B and the plane C from the origin of coordinates is a Y-axis orthogonal direction, and the direction from the origin of coordinates to the bottom surface of the stator close to the first piezoelectric ceramic piece along the axis of the stator is a Z-axis orthogonal direction;
if the spherical rotor needs to be driven to rotate around the X axis:
applying a first excitation signal to the first, second, fifth and sixth piezoelectric ceramic plates, applying a second excitation signal to the third and eighth piezoelectric ceramic plates, applying a third excitation signal to the fourth and seventh piezoelectric ceramic plates, wherein the first to third excitation signals are all same-frequency and same-amplitude alternating-current harmonic signals, the first excitation signal advances by pi/2 of the second excitation signal in time phase difference, and the second excitation signal is opposite to the third excitation signal in phase, so that the piezoelectric vibrator simultaneously excites a radial bending vibration mode and an axial bending vibration mode in the Y-axis direction, as shown in fig. 6 and 7; by coupling the radial bending vibration mode and the axial bending vibration mode in the Y-axis direction, a micro elliptical motion perpendicular to the X-axis is formed on the driving surface of the piezoelectric vibrator, and the spherical rotor is driven to rotate around the X-axis through friction, as shown in fig. 9;
if the first excitation signal needs to reversely rotate around the X axis, the phase of the first excitation signal is inverted;
if the spherical rotor needs to be driven to rotate around the Y axis:
applying a first excitation signal to the third, fourth, seventh and eighth piezoelectric ceramic plates, applying a second excitation signal to the first and sixth piezoelectric ceramic plates, applying a third excitation signal to the second and fifth piezoelectric ceramic plates, wherein the first to third excitation signals are all same-frequency and same-amplitude alternating-current harmonic signals, the first excitation signal advances by pi/2 of the second excitation signal in time phase difference, and the second excitation signal is opposite to the third excitation signal in phase, so that the piezoelectric vibrator simultaneously excites a radial bending vibration mode and an axial bending vibration mode in the X-axis direction, as shown in fig. 6 and 8; by coupling the radial bending vibration mode and the axial bending vibration mode in the X-axis direction, a micro elliptical motion perpendicular to the Y-axis is formed on the driving surface of the piezoelectric vibrator, and the spherical rotor is driven to rotate around the Y-axis through friction, as shown in fig. 10;
if the first excitation signal needs to reversely rotate around the Y axis, the phase of the first excitation signal is inverted;
if the spherical rotor needs to be driven to rotate around the Z axis:
applying a fourth excitation signal to the first piezoelectric ceramic plate and the sixth piezoelectric ceramic plate, applying a fifth excitation signal to the second piezoelectric ceramic plate and the fifth piezoelectric ceramic plate, applying a sixth excitation signal to the third piezoelectric ceramic plate and the eighth piezoelectric ceramic plate, applying a seventh excitation signal to the fourth piezoelectric ceramic plate and the seventh piezoelectric ceramic plate, wherein the first excitation signal to the seventh excitation signal are all alternating-current harmonic signals with the same frequency and the same amplitude, the fourth excitation signal leads the sixth excitation signal pi/2 in time phase difference, the fourth excitation signal is opposite to the sixth excitation signal in phase, and the fifth excitation signal is opposite to the seventh excitation signal in phase, so that the piezoelectric vibrator has two orthogonal axial bending vibration modes at the same time, as shown in fig. 7 and 8; by coupling two orthogonal axial bending vibration modes, a micro elliptical motion perpendicular to the Z axis is formed on the driving surface of the piezoelectric vibrator, and the spherical rotor is driven to rotate around the Z axis through friction, as shown in FIG. 11;
if a reverse rotation around the Z axis is required, the fourth excitation signal is changed to lag the sixth excitation signal pi/2 in time phase difference.
The multi-freedom-degree piezoelectric actuator can realize multi-freedom-degree motion under the advantages of retaining the simple and flexible structure of the piezoelectric actuator, quick response, no electromagnetic interference and the like. The piezoelectric vibrator structure can be simplified by adopting the patch type spherical shell stator, the size of the actuator is effectively reduced, and in addition, the spherical shell stator is adopted to be in spherical contact with the spherical surface of the spherical rotor for driving, so that the driving surface is increased, and the efficiency of the actuator is improved.
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 commonly understood by one of ordinary skill in the art to which this invention belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the prior art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.
While the foregoing is directed to embodiments of the present invention, other and further details of the invention may be had by the present invention, it should be understood that the foregoing description is merely illustrative of the present invention and that no limitations are intended to the scope of the invention, except insofar as modifications, equivalents, improvements or modifications are within the spirit and principles of the invention.
Claims (5)
1. The three-degree-of-freedom piezoelectric actuator is characterized by comprising a piezoelectric vibrator, a spherical rotor, a clamping frame and first to fourth connecting rods;
the piezoelectric vibrator includes a stator, and first to eighth piezoelectric ceramic pieces;
the stator is a hollow sphere table with two open ends, and is symmetrical about a neutral plane between two bottom surfaces;
the first to eighth piezoelectric ceramic plates have the same structure and are block spherical shells, and each block spherical shell comprises an outer wall, an inner wall and first to fourth side walls which are sequentially connected end to end, wherein the diameter of the inner wall is equal to the diameter of the outer spherical surface of the stator;
the first piezoelectric ceramic piece, the third piezoelectric ceramic piece, the fifth piezoelectric ceramic piece and the seventh piezoelectric ceramic piece are circumferentially and uniformly arranged on the outer spherical surface of the stator, the second piezoelectric ceramic piece, the fourth piezoelectric ceramic piece, the sixth piezoelectric ceramic piece and the seventh piezoelectric ceramic piece are circumferentially and uniformly arranged on the outer spherical surface of the stator, and the first piezoelectric ceramic piece, the second piezoelectric ceramic piece, the third piezoelectric ceramic piece, the fourth piezoelectric ceramic piece, the fifth piezoelectric ceramic piece, the sixth piezoelectric ceramic piece, the seventh piezoelectric ceramic piece and the eighth piezoelectric ceramic piece are symmetrical about a neutral plane between two bottom surfaces of the stator; the first side wall and the third side wall of the first piezoelectric ceramic plate to the eighth piezoelectric ceramic plate are parallel to the bottom surface of the stator, and the second side wall and the fourth side wall of the first piezoelectric ceramic plate to the eighth piezoelectric ceramic plate are coplanar with the axis of the stator; the first piezoelectric ceramic piece and the eighth piezoelectric ceramic piece are polarized along the thickness direction and the polarization direction is inward;
the spherical rotor adopts a sphere or a spherical table symmetrical about a neutral plane between two bottom surfaces, is arranged in the stator and is contacted with the spherical surface of the stator;
the clamping frame contains the stator; the first to fourth connecting rods are circumferentially and uniformly arranged outside the stator, one ends of the first to fourth connecting rods are fixedly connected with the junction of four pitch circles and the pitch diameter in a one-to-one correspondence mode in the working mode of the stator respectively, and the other ends of the first to fourth connecting rods are fixedly connected with the clamping frame.
2. The three degree of freedom piezoelectric actuator of claim 1 wherein the clamping frame is a square frame with threaded through holes for attachment to the outside at the four midpoints of the four sides.
3. The three degree of freedom piezoelectric actuator of claim 1 wherein the ends of the first through fourth connecting rods adjacent the stator are concave spherical surfaces that mate with the stator.
4. The three degree of freedom piezoelectric actuator of claim 1 wherein the spherical rotor employs a spherical table symmetrical about a neutral plane between two bottom surfaces, provided with a circular through hole along an axis for setting an output shaft.
5. The method of operating a three degree of freedom piezoelectric actuator of claim 1, comprising the steps of:
the spherical center of the stator is a Cartesian coordinate system origin, the angular bisection plane of the plane where the second side wall and the fourth side wall of the first piezoelectric ceramic piece are located is a plane A, the angular bisection plane of the plane where the second side wall and the fourth side wall of the third piezoelectric ceramic piece are located is a plane B, the neutral plane between the two bottom surfaces of the stator is C, the direction outwards along the intersection line of the plane A and the plane C from the origin of coordinates is an X-axis orthogonal direction, the direction outwards along the intersection line of the plane B and the plane C from the origin of coordinates is a Y-axis orthogonal direction, and the direction from the origin of coordinates to the bottom surface of the stator close to the first piezoelectric ceramic piece along the axis of the stator is a Z-axis orthogonal direction;
if the spherical rotor needs to be driven to rotate around the X axis:
applying a first excitation signal to the first, second, fifth and sixth piezoelectric ceramic plates, applying a second excitation signal to the third and eighth piezoelectric ceramic plates, applying a third excitation signal to the fourth and seventh piezoelectric ceramic plates, wherein the first to third excitation signals are all same-frequency and same-amplitude alternating-current harmonic signals, the first excitation signal advances by pi/2 of the second excitation signal in time phase difference, and the second excitation signal is opposite to the third excitation signal in phase, so that the piezoelectric vibrator simultaneously excites a radial bending vibration mode and an axial bending vibration mode in the Y-axis direction; through the coupling of the radial bending vibration mode and the axial bending vibration mode in the Y-axis direction, a driving surface of the piezoelectric vibrator forms a micro elliptical motion perpendicular to the X-axis, and the spherical rotor is driven to rotate around the X-axis through friction;
if the first excitation signal needs to reversely rotate around the X axis, the phase of the first excitation signal is inverted;
if the spherical rotor needs to be driven to rotate around the Y axis:
applying a first excitation signal to the third, fourth, seventh and eighth piezoelectric ceramic plates, applying a second excitation signal to the first and sixth piezoelectric ceramic plates, applying a third excitation signal to the second and fifth piezoelectric ceramic plates, wherein the first to third excitation signals are all same-frequency and same-amplitude alternating-current harmonic signals, the first excitation signal advances by pi/2 of the second excitation signal in time phase difference, and the second excitation signal is opposite to the third excitation signal in phase, so that the piezoelectric vibrator simultaneously excites a radial bending vibration mode and an axial bending vibration mode in the X-axis direction; through the coupling of the radial bending vibration mode and the axial bending vibration mode in the X-axis direction, the micro elliptical motion perpendicular to the Y-axis is formed on the driving surface of the piezoelectric vibrator, and the spherical rotor is driven to rotate around the Y-axis through friction;
if the first excitation signal needs to reversely rotate around the Y axis, the phase of the first excitation signal is inverted;
if the spherical rotor needs to be driven to rotate around the Z axis:
applying a fourth excitation signal to the first piezoelectric ceramic plate and the sixth piezoelectric ceramic plate, applying a fifth excitation signal to the second piezoelectric ceramic plate and the fifth piezoelectric ceramic plate, applying a sixth excitation signal to the third piezoelectric ceramic plate and the eighth piezoelectric ceramic plate, applying a seventh excitation signal to the fourth piezoelectric ceramic plate and the seventh piezoelectric ceramic plate, wherein the first excitation signal to the seventh excitation signal are all alternating-current harmonic signals with the same frequency and the same amplitude, the fourth excitation signal leads the sixth excitation signal pi/2 in time phase difference, the fourth excitation signal is opposite to the phase of the sixth excitation signal, the phase of the fifth excitation signal is opposite to the phase of the seventh excitation signal, and the piezoelectric vibrator simultaneously has two orthogonal axial bending vibration modes; through the coupling of two orthogonal axial bending vibration modes, a micro elliptical motion perpendicular to a Z axis is formed on a driving surface of the piezoelectric vibrator, and the spherical rotor is driven to rotate around the Z axis through friction;
if a reverse rotation around the Z axis is required, the fourth excitation signal is changed to lag the sixth excitation signal pi/2 in time phase difference.
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| Application Number | Priority Date | Filing Date | Title |
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| CN202310251801.4A CN116191929A (en) | 2023-03-16 | 2023-03-16 | Three-degree-of-freedom piezoelectric actuator and working method thereof |
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| CN202310251801.4A CN116191929A (en) | 2023-03-16 | 2023-03-16 | Three-degree-of-freedom piezoelectric actuator and working method thereof |
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