CN115001308A - Three-degree-of-freedom piezoelectric drive unit and planar piezoelectric driver - Google Patents

Three-degree-of-freedom piezoelectric drive unit and planar piezoelectric driver Download PDF

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Publication number
CN115001308A
CN115001308A CN202210681520.8A CN202210681520A CN115001308A CN 115001308 A CN115001308 A CN 115001308A CN 202210681520 A CN202210681520 A CN 202210681520A CN 115001308 A CN115001308 A CN 115001308A
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piezoelectric
degree
freedom
tightening
movable terminal
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魏凤龙
郭抗
倪明阳
隋永新
杨怀江
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Changchun National Extreme Precision Optics Co ltd
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Changchun National Extreme Precision Optics Co ltd
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    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02N—ELECTRIC MACHINES NOT OTHERWISE PROVIDED FOR
    • H02N2/00—Electric machines in general using piezoelectric effect, electrostriction or magnetostriction
    • H02N2/0095—Electric machines in general using piezoelectric effect, electrostriction or magnetostriction producing combined linear and rotary motion, e.g. multi-direction positioners
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02N—ELECTRIC MACHINES NOT OTHERWISE PROVIDED FOR
    • H02N2/00—Electric machines in general using piezoelectric effect, electrostriction or magnetostriction
    • H02N2/02—Electric machines in general using piezoelectric effect, electrostriction or magnetostriction producing linear motion, e.g. actuators; Linear positioners ; Linear motors
    • H02N2/021—Electric machines in general using piezoelectric effect, electrostriction or magnetostriction producing linear motion, e.g. actuators; Linear positioners ; Linear motors using intermittent driving, e.g. step motors, piezoleg motors
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02N—ELECTRIC MACHINES NOT OTHERWISE PROVIDED FOR
    • H02N2/00—Electric machines in general using piezoelectric effect, electrostriction or magnetostriction
    • H02N2/02—Electric machines in general using piezoelectric effect, electrostriction or magnetostriction producing linear motion, e.g. actuators; Linear positioners ; Linear motors
    • H02N2/028—Electric machines in general using piezoelectric effect, electrostriction or magnetostriction producing linear motion, e.g. actuators; Linear positioners ; Linear motors along multiple or arbitrary translation directions, e.g. XYZ stages
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02N—ELECTRIC MACHINES NOT OTHERWISE PROVIDED FOR
    • H02N2/00—Electric machines in general using piezoelectric effect, electrostriction or magnetostriction
    • H02N2/02—Electric machines in general using piezoelectric effect, electrostriction or magnetostriction producing linear motion, e.g. actuators; Linear positioners ; Linear motors
    • H02N2/04—Constructional details

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Abstract

The application relates to the field of piezoelectric driving devices and discloses a three-degree-of-freedom piezoelectric driving unit, which comprises: the piezoelectric actuator comprises a base, three one-dimensional piezoelectric stacks, a shell, a guide diaphragm and a flexible guide rod, wherein the three one-dimensional piezoelectric stacks are arranged on the upper surface of the base; the shell is arranged above the base; the movable terminal is positioned above the three one-dimensional piezoelectric stacks; the lower end of the flexible guide rod is connected with the base through an elastic piece, and the upper end of the flexible guide rod is connected with the bottom of the movable terminal. Through the mutual cooperation of the three one-dimensional piezoelectric stacks, the flexibility of the piezoelectric driving unit can be effectively improved, so that the piezoelectric driving unit has multiple degrees of freedom, and the application range of the piezoelectric driving unit is further improved. The application also discloses a planar piezoelectric driver, which comprises two groups of piezoelectric driving components, wherein each group of piezoelectric driving components comprises a plurality of the three-degree-of-freedom piezoelectric driving units, and continuous and precise stepping motion output of the planar piezoelectric driver in any direction in a plane can be realized under the control of the driving voltage time sequence.

Description

Three-degree-of-freedom piezoelectric drive unit and planar piezoelectric driver
Technical Field
The present disclosure relates to piezoelectric driving devices, and particularly to a three-degree-of-freedom piezoelectric driving unit, and a planar piezoelectric driver including the three-degree-of-freedom piezoelectric driving unit.
Background
The piezoelectric actuator is designed by utilizing the inverse piezoelectric effect of a piezoelectric material and can output compact motion, and the piezoelectric actuator is widely applied to various fields due to excellent performances of high precision, large stroke, quick response and the like.
The traditional piezoelectric actuator can only realize linear motion output in a single direction, so that the application range of the piezoelectric actuator is limited, and particularly for complex motion, the piezoelectric actuator is difficult to popularize and apply.
Disclosure of Invention
One objective of the present application is to provide a three-degree-of-freedom piezoelectric driving unit, which can improve the flexibility of motion output thereof, and further improve the application range thereof, and another objective is to provide a planar piezoelectric driver including the three-degree-of-freedom piezoelectric driving unit, which can implement continuous stepping motion output in any direction in a plane.
In order to achieve the above purpose, the present application provides the following technical solutions:
a three degree-of-freedom piezoelectric drive unit comprising:
a base;
the three one-dimensional piezoelectric stacks are arranged on the upper surface of the base and are uniformly distributed along the circumferential direction;
the shell is arranged above the base, and the three one-dimensional piezoelectric stacks are positioned in the shell;
the guide membrane is arranged in the shell and is positioned above the driving ends of the three one-dimensional piezoelectric stacks;
the movable terminal is positioned on the upper surface of the guide membrane, the upper end of the movable terminal extends out of the shell, and the upper ends of the three one-dimensional piezoelectric stacks penetrate through the guide membrane to be in contact with the lower surface of the movable terminal;
the lower end of the flexible guide rod is connected with the base through an elastic piece, the upper end of the flexible guide rod is connected with the bottom of the movable terminal, and the elastic piece is used for applying pre-tightening force towards the one-dimensional piezoelectric stack to the movable terminal through the flexible guide rod;
three one-dimensional piezoelectric stacks are used for being deformed in a telescopic mode under corresponding driving voltage so as to control the movable terminal to generate translational motion in the z direction, rotary motion around the x axis and rotary motion around the y axis relative to the base.
Preferably, the elastic part comprises a first pre-tightening disc spring, a through hole for the flexible guide rod to penetrate out is formed in the middle of the base, a cavity for accommodating the first pre-tightening disc spring is formed in the bottom of the base, the first pre-tightening disc spring is sleeved at the lower end of the flexible guide rod, a pre-tightening nut is connected to the lower end of the flexible guide rod in a threaded mode, and the pre-tightening nut is used for tightly pressing the first pre-tightening disc spring on the top surface of the cavity.
Preferably, the flexible guide rod comprises a top threaded connecting end, a thin rod and a bottom threaded connecting end which are sequentially arranged from top to bottom, the top threaded connecting end is connected with the movable terminal, and the pre-tightening nut is connected to the bottom threaded connecting end.
Preferably, the outer side surface of the movable terminal is tapered from bottom to top.
Preferably, the casing includes shell and clamping ring, the lower extreme of shell with the base is connected, the clamping ring is used for with the direction diaphragm compresses tightly in the upper end of shell.
Preferably, the upper end of the one-dimensional piezoelectric stack is a spherical end, and the spherical end is in point contact with the lower surface of the movable terminal.
A planar piezoelectric driver comprises two groups of piezoelectric driving assemblies, wherein each group of piezoelectric driving assemblies comprises a plurality of the three-degree-of-freedom piezoelectric driving units, the three-degree-of-freedom piezoelectric driving units are uniformly distributed along the circumferential direction, the planar piezoelectric driver further comprises a rotor, the rotor is positioned above a movable terminal of each three-degree-of-freedom piezoelectric driving unit, and the two groups of piezoelectric driving assemblies alternately drive the rotor to generate step motion output under the friction coupling effect.
Preferably, one three-degree-of-freedom piezoelectric drive unit of another group of piezoelectric drive assemblies is arranged between two adjacent three-degree-of-freedom piezoelectric drive units of one group of piezoelectric drive assemblies.
Preferably, the three-degree-of-freedom piezoelectric driving unit is located above the supporting assembly, and the pre-tightening assembly is used for applying pre-tightening force towards the three-degree-of-freedom piezoelectric driving unit to the mover.
Preferably, the pre-tightening assembly comprises a pre-tightening screw, a pressing plate, a ball and a second pre-tightening disc spring, the pre-tightening screw sequentially penetrates through the supporting assembly and the mover from bottom to top, the tail end of the pre-tightening screw is connected with the pressing plate, and the pre-tightening screw is used for pressing the second pre-tightening disc spring to the bottom of the supporting assembly; the bottom of the pressing plate is provided with a groove for containing the ball, and the ball is in contact with the upper surface of the rotor.
Compared with the prior art, the technical scheme has the following advantages:
the application provides a three degree of freedom piezoelectricity drive unit, includes: the piezoelectric actuator comprises a base, three one-dimensional piezoelectric stacks, a shell, a guide diaphragm and a flexible guide rod, wherein the three one-dimensional piezoelectric stacks are arranged on the upper surface of the base and are uniformly distributed along the circumferential direction of the flexible guide rod; the shell is arranged above the base, and the three one-dimensional piezoelectric stacks are positioned in the shell; the guide membrane is arranged in the shell and is positioned above the driving ends of the three one-dimensional piezoelectric stacks; the movable terminal is positioned on the upper surface of the guide membrane, and the upper end of the movable terminal extends out of the shell; the lower end of the flexible guide rod is connected with the base through an elastic piece, and the upper end of the flexible guide rod is connected with the bottom of the movable terminal. The three one-dimensional piezoelectric stacks are used for being deformed in a telescopic mode under corresponding driving voltage so as to control the movable terminal to generate translational motion in the z direction, rotary motion around the x axis and rotary motion around the y axis relative to the base. Through the voltage regulation and control of the three one-dimensional piezoelectric stacks, the movable terminal can have three degrees of freedom, so that the flexibility of the movable terminal can be effectively improved, and the application range of the movable terminal is further improved.
The planar piezoelectric driver comprises two groups of piezoelectric driving components, wherein each group of piezoelectric driving components comprises a plurality of three-degree-of-freedom piezoelectric driving units, and under the control of a driving voltage time sequence, the planar piezoelectric driver can continuously and precisely output stepping motion in any direction in a plane, so that the application range of the planar piezoelectric driver is enlarged.
Drawings
In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings needed to be used in the description of the embodiments or the prior art will be briefly introduced below, it is obvious that the drawings in the following description are only embodiments of the present application, and for those skilled in the art, other drawings can be obtained according to the provided drawings without creative efforts.
Fig. 1 is a schematic structural diagram of a three-degree-of-freedom piezoelectric driving unit according to an embodiment of the present disclosure;
FIG. 2 is a schematic diagram of the operation principle of the three-degree-of-freedom piezoelectric driving unit;
FIG. 3 is a diagram illustrating the relationship between two rotational degrees of freedom of a three-degree-of-freedom piezoelectric driving unit;
fig. 4 is a diagram of a motion trajectory of a movable terminal of a three-degree-of-freedom piezoelectric drive unit;
FIG. 5 is a schematic structural diagram of a planar piezoelectric actuator according to an embodiment of the present application;
FIG. 6 is a front cross-sectional view of a planar piezoelectric actuator;
FIG. 7 is a diagram of a layout of four three-degree-of-freedom piezoelectric driving units of a planar piezoelectric actuator;
FIG. 8 is a diagram of a layout of six three-degree-of-freedom piezoelectric drive units of a planar piezoelectric actuator;
FIG. 9 is a schematic view of the stepped motion of a planar piezoelectric actuator in the P + direction;
fig. 10 is a schematic diagram of the process of stepping movement in the P + direction of the planar piezoelectric actuator.
The reference numbers are as follows:
1 is a moving shaft, 2 is a pre-tightening screw, 3 is a pressing plate, and 4 is a ball;
5A, 5B, 5C, and 5D are three-degree-of-freedom piezoelectric drive units, 51 is a movable terminal, 52 is a guide diaphragm, 53 is a press ring, 54 is a housing, 55A, 55B, and 55C are one-dimensional piezoelectric stacks, 56 is a base, 57 is a first pre-tightening disc spring, 58 is a pre-tightening nut, 59 is a first pre-tightening flat gasket, and 60 is a flexible guide rod.
6 is a second pre-tightening disc spring, 7 is a second pre-tightening flat gasket, and 8 is a base.
Detailed Description
The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are only a part of the embodiments of the present application, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.
Referring to fig. 1, fig. 1 is a schematic structural diagram of a three-degree-of-freedom piezoelectric driving unit according to an embodiment of the present disclosure.
The three-degree-of-freedom piezoelectric driving unit provided by the embodiment of the application comprises: the piezoelectric actuator comprises a base 56, three one-dimensional piezoelectric stacks 55A, 55B and 55C, a shell, a guide diaphragm 52 and a flexible guide rod 60, wherein the three one-dimensional piezoelectric stacks 55A, 55B and 55C are arranged on the upper surface of the base 56 and are uniformly distributed along the circumferential direction of the flexible guide rod 60, the upper ends of the one-dimensional piezoelectric stacks are preferably spherical ends, and the abrasion of the one-dimensional piezoelectric stacks can be reduced through the spherical ends, so that the service life is prolonged; the shell is arranged above the base 56, and the three one-dimensional piezoelectric stacks 55A, 55B and 55C are positioned in the shell; the guide membrane 52 is arranged in the shell and is positioned on the upper surface of the guide membrane 52; the movable terminal 51 is located on the upper surface of the guide diaphragm 52, the upper end of the movable terminal extends out of the housing, the upper ends of the three one-dimensional piezoelectric stacks 55A, 55B and 55C pass through the guide diaphragm 52 to be in contact with the lower surface of the movable terminal 52, the spherical ends of the three one-dimensional piezoelectric stacks 55A, 55B and 55C are in point contact with the lower surface of the movable terminal 51, and the outer side surface of the movable terminal 51 is preferably in a structure tapered from bottom to top, such as a conical structure; the lower end of the flexible guide bar 60 is connected to the base 56 by an elastic member, and the upper end is connected to the bottom of the movable terminal 51.
As shown in fig. 2 and 3, three of the one-dimensional piezoelectric stacks 55A, 55B, and 55C are longitudinally-telescopic piezoelectric stacks, and are respectively driven at a driving voltage U i1 、U i2 And U i3 Under the driving action of the piezoelectric stack, longitudinal stretching deformation can be generated, the hysteresis characteristic of the piezoelectric stack is ignored, and the deformation delta l of the three piezoelectric stacks is considered to be linear relation between the deformation of the piezoelectric stack and the driving voltage A 、δl B And δ l C This can be derived from the following formula:
Figure BDA0003698341870000051
in the formula, k 33 The voltage deformation coefficient of the one-dimensional piezoelectric stack ceramic is shown, and V is the rated driving voltage of the one-dimensional piezoelectric stack.
The movable terminal 51 is constrained by the guide membrane 52 and the flexible guide rod 60, and under the driving action of the three one-dimensional piezoelectric stacks, the movable terminal can generate a translational motion in the z direction, a rotational motion around the p axis and a rotational motion around the q axis relative to the base 56, and the motion posture of the movable terminal 51 and the deformation δ l of the three piezoelectric stacks A 、δl B And δ l C Can be calculated from the following formula:
Figure BDA0003698341870000061
in the formula: ZZ is the amount of z-translation of the movable terminal 51 in the o-xyz coordinate system, R q 、R q The rotation angles of the movable terminal 51 around the q-axis and the p-axis in the o-xyz coordinate system, respectively, θ is the angle between the arbitrary axis p and the coordinate axis x, and the p-axis and the q-axis are orthogonal to each other at the origin of the o-xyz coordinate system.
The center point M of the lower end of the movable terminal 51, which is also the center point of the guide diaphragm 52;
when ZZ is not ZZ min When 0, M coincides with the origin o of the coordinate system o-xyz；
When in use
Figure BDA0003698341870000062
When M is located at the highest point in the Z direction, the motion space of the M point in an o-xyz coordinate system can be obtained
Figure BDA0003698341870000063
The distance between the center point N and the point M of the upper end plane of the movable terminal 51 is h, and when the three one-dimensional piezoelectric stacks 55A, 55B and 55C drive the movable terminal 51 to move, the reachable space of the center point N of the upper end surface of the movable terminal in the o-pqz coordinate system is
Figure BDA0003698341870000071
As shown in fig. 4, in particular, when R p When the current is 0rad, the movable terminal 51 can only generate a translational motion in the z direction and a rotational motion around the q axis, the rotational center of the rotational motion is the center point M of the lower end surface of the movable terminal 51, the center point N of the upper end of the movable terminal 51 can only move in the plane pz, and the motion space of N in the pz plane is
Figure BDA0003698341870000072
By regulating and controlling the voltages of the three one-dimensional piezoelectric stacks, the movable terminal 51 can have three degrees of freedom, so that the flexibility of the piezoelectric driving unit can be effectively improved, the piezoelectric driving unit has multiple degrees of freedom, and the application range of the piezoelectric driving unit is further improved.
As shown in fig. 4, the driving voltage U is applied to three piezoelectric stacks i1 、U i2 、U i3 The waveform of the three-degree-of-freedom piezoelectric driving unit can be modulated, so that the central point N at the upper end of the movable terminal 51 of the three-degree-of-freedom piezoelectric driving unit can follow a fixed contour track>②->③->④->⑤->⑥->Clockwise, and the center point N of the upper end of the movable terminal 51 can follow the fixed contour track>⑥->⑤->④->③->②->(ii) counterclockwise.
In order to facilitate the assembly of the guide diaphragm 52, the housing comprises a shell 54 and a press ring 53, the lower end of the shell 54 is connected with a base 56, the press ring 53 can press the wire diaphragm on the upper end of the shell 54, wherein the shell 54 is preferably a cylinder, the press ring 53 is preferably a circular ring, and the press ring 53, the shell 54 and the base 56 can be connected by penetrating a bolt from bottom to top.
In some embodiments, the elastic element includes a first pre-tightening disc spring 57, a through hole for the flexible guide rod 60 to pass through is formed in the middle of the base 56, a cavity for accommodating the first pre-tightening disc spring 57 is formed in the bottom of the base 56, the first pre-tightening disc spring 57 is sleeved at the lower end of the flexible guide rod 60, a pre-tightening nut 58 is connected to the lower end of the flexible guide rod 60 in a threaded manner, the pre-tightening nut 58 can press the first pre-tightening disc spring 57 against the top surface of the cavity, a first pre-tightening flat gasket 59 can be arranged between the pre-tightening nut 58 and the first pre-tightening disc spring 57, and a downward pre-tightening force can be applied to the movable terminal 51 through the first pre-tightening disc spring 57, so that the rigidity of the piezoelectric drive unit is improved.
In some embodiments, the flexible guide rod 60 includes a top threaded end, a thin rod, and a bottom threaded end sequentially arranged from top to bottom, the top threaded end is connected to the movable terminal 51, the pre-tightening nut 58 is connected to the bottom threaded end, and the outer diameters of the top threaded end and the bottom threaded end are larger than the outer diameter of the thin rod, so as to improve the connection stability of the flexible guide rod 60 with the movable terminal 51 and the pre-tightening nut 58. Wherein the diameter of the thin rod is smaller than the inner diameter of the through hole to ensure that the thin rod can have a certain range of motion in the through hole when the movable terminal 51 rotates. In addition, a transition section is arranged between the thin rod and the threaded connection end at the bottom, and the outer diameter of the transition section is gradually reduced from bottom to top, for example, the transition section is of a conical structure.
The embodiment of the application further provides a planar piezoelectric actuator, which comprises two groups of piezoelectric drive assemblies, wherein each group of piezoelectric drive assemblies comprises a plurality of three-degree-of-freedom piezoelectric drive units, the three-degree-of-freedom piezoelectric drive units are uniformly distributed along the circumferential direction, the planar piezoelectric actuator further comprises a rotor, and the rotor is located above the movable terminal 51 of the three-degree-of-freedom piezoelectric drive unit. When the planar piezoelectric driver is static, the two groups of piezoelectric driving assemblies simultaneously keep clamping of the planar piezoelectric driver, and when the planar piezoelectric driver moves in a stepping mode, the two groups of piezoelectric driving assemblies alternately drive the rotor to generate stepping motion output under the action of frictional coupling under the control of a driving voltage time sequence. In order to improve the support and motion stability of the planar piezoelectric actuator, a three-degree-of-freedom piezoelectric drive unit of another group of piezoelectric drive components is arranged between two adjacent three-degree-of-freedom piezoelectric drive units of one group of piezoelectric drive components. Compared with the traditional linear piezoelectric actuator with a single motion direction, the continuous and precise stepping motion output can be realized in any direction in a plane. In addition, the piezoelectric linear actuator has the advantages of small size and compact structure, and has the characteristics of large driving force, high structural rigidity, high precision and quick response of the traditional linear piezoelectric actuator.
In this embodiment, as shown in fig. 5, fig. 6, and fig. 7, taking four three-degree-of-freedom piezoelectric driving units 5A, 5B, 5C, and 5D as an example for explanation, the four three-degree-of-freedom piezoelectric driving units 5A, 5B, 5C, and 5D are uniformly distributed along a circumferential direction, that is, the four three-degree-of-freedom piezoelectric driving units are distributed in a square shape and located at four corners of the square respectively, driving voltages of two three-degree-of-freedom piezoelectric driving units located at opposite corners of the square are the same, and respectively constitute a piezoelectric driving component i and a piezoelectric driving component ii, that is, 5A and 5C constitute a piezoelectric driving component i, and a voltage U is used for driving the piezoelectric driving component i 1j (j is 1,2,3) drive, 5B and 5D form a piezoelectric drive component II, and the piezoelectric drive component II is driven by a voltage U 2j (j ═ 1,2,3) drive.
In this embodiment, as shown in fig. 8, taking six three-degree-of-freedom piezoelectric driving units 5a, 5b, 5c, 5d, 5e, and 5f as an example for explanation, the six three-degree-of-freedom piezoelectric driving units 5a, 5b, 5c, 5d, 5e, and 5f are uniformly distributed along the circumferential direction, that is, the six three-degree-of-freedom piezoelectric driving units are distributed in a regular hexagon and are respectively located at six corners of a regular hexagon, the driving voltages of the three-degree-of-freedom piezoelectric driving units located in a regular triangle are the same, and respectively constitute a piezoelectric driving component i and a piezoelectric driving component ii, that is, the piezoelectric driving component i is constituted by the six-degree-of-freedom piezoelectric driving units 5a, 5b, 5d, and 5e, and the piezoelectric driving component i is constituted by the voltage U, and the voltage U is U 1j (j-1, 2,3) drive, 5b,5d and 5f form a piezoelectric driving component II and is driven by a voltage U 2j And (j is 1,2 and 3) driving.
In order to improve the rigidity of the planar piezoelectric actuator, the planar piezoelectric actuator further comprises a pre-tightening assembly and a supporting assembly, each three-degree-of-freedom piezoelectric driving unit is positioned above the supporting assembly and fixedly connected to the supporting assembly, the supporting assembly is preferably a base 8 of a flat plate structure, and a boss for positioning the three-degree-of-freedom piezoelectric driving unit can be arranged in the middle of the base 8; the pre-tightening assembly is used for applying pre-tightening force towards the three-degree-of-freedom piezoelectric driving unit to the rotor, and the overall rigidity of the planar piezoelectric driver can be improved through the pre-tightening assembly. The pre-tightening assembly comprises a pre-tightening screw 2, a pressing plate 3, a ball 4 and a second pre-tightening disc spring 6, the pre-tightening screw 2 sequentially penetrates out of the supporting assembly and the mover from bottom to top, the tail end of the pre-tightening screw is connected with the pressing plate 3, the mover is a moving shaft 1, the pre-tightening screw 2 can tightly press the second pre-tightening disc spring 6 to the bottom of the base 56, a second pre-tightening flat gasket 7 can be arranged between the pre-tightening screw 2 and the second pre-tightening disc spring 6, and in addition, a cavity for accommodating the head of the pre-tightening screw 2 and the second pre-tightening disc spring 6 can be arranged at the bottom of the base 56; the bottom of the pressing plate 3 is provided with a groove for accommodating the ball 4, the ball 4 is in contact with the upper surface of the moving shaft 1, the friction force between the ball 4 and the moving shaft 1 can be reduced, and the service life of the moving shaft 1 is further prolonged.
As shown in fig. 9 and 10, when the planar piezoelectric actuator works specifically, a predetermined driving waveform is adopted, and under the alternate driving of the piezoelectric driving assembly i and the piezoelectric driving assembly ii, the mover of the planar piezoelectric actuator can realize continuous and precise stepping motion along any direction P in the plane XY, and an included angle between the motion direction P and the X axis is θ.
In an initial state, the upper ends of the piezoelectric driving component I and the piezoelectric driving component II are contacted with the motion shaft 1, and the upper end points N of six piezoelectric driving units forming the piezoelectric driving component I and the piezoelectric driving component II are all positioned at a z-direction half-stroke position, namely
Figure BDA0003698341870000101
The process of the planar piezoelectric actuator in the P + direction stepping motion is as follows:
a. initially, driving the piezoelectric driving component I to enable the upper end point of the piezoelectric driving component I to be located at the position of the first point of the contour track, and driving the piezoelectric driving component II to enable the upper end point of the piezoelectric driving component II to be located at the position of the fourth point of the contour track;
b. driving the piezoelectric driving component I to make its upper end point move from point to point along the contour track, driving the piezoelectric driving component II to make its upper end point move from point to point along the contour track, and driving the upper end point of the piezoelectric driving component I to make its movement shaft 1 move along P + direction by delta l under the action of frictional coupling 1 ；
c. The upper end point of the piezoelectric driving component I is kept stationary at the third point, the piezoelectric driving component II is driven to enable the upper end point to move to the first point from the sixth point along the contour track, and the moving shaft 1 is kept stationary under the clamping action of the piezoelectric driving component I;
d. driving the piezoelectric driving component I to enable the upper end point of the piezoelectric driving component I to move from the third point to the fourth point along the contour track, and keeping the motion shaft 1 still under the clamping action of the piezoelectric driving component II;
e. driving the piezoelectric driving component I to make its upper end point move from point to point along the contour track, driving the piezoelectric driving component II to make its upper end point move from point to point along the contour track, and driving the upper end point of the piezoelectric driving component II to make its movement shaft 1 move along P + direction by delta l under the action of frictional coupling 2 ；
f. And driving the piezoelectric driving component I to enable the upper end point of the piezoelectric driving component I to move from the sixth point to the fifth point along the contour track, and keeping the movement shaft 1 still under the clamping action of the piezoelectric driving component II.
After the planar piezoelectric actuator completes the above-mentioned a-b-c-d-e-f process, the moving axis 1 moves to P + by one step, which is denoted by Δ L, and can be obtained by the following formula:
ΔL＝Δl 1 +Δl 2
the a-b-c-d-e-f-a process is repeated in a circulating mode, and the plane driver can realize continuous stepping movement in the P + direction.
The a-f-e-d-c-b-a process is repeated in a cycle, and the plane driver can realize continuous stepping movement in the P-direction.
When the driver moves in the P direction step by step, the friction force F between the piezoelectric driving component I and the moving shaft 1 f1 And the friction force F between the piezoelectric driving component II and the motion shaft f2 The motion axis 1 is driven alternately to produce a stepping motion, both being equal and having the following relation:
F f1 ＝F f2 ＝F f ＝f max
when the driver moves in the P direction in a stepping mode, the capability of the motion shaft 1 for driving the load to move is represented by F, that is, the driving force of the novel planar piezoelectric driver in the P direction can be calculated by the following formula:
F＝F f -f
wherein f is the rolling friction resistance between the upper surface of the moving shaft 1 and the ball 4 when the driver is dynamic.
The embodiments in the present description are described in a progressive manner, each embodiment focuses on differences from other embodiments, and the same and similar parts among the embodiments are referred to each other.
The three-degree-of-freedom piezoelectric driving unit and the planar piezoelectric driver provided by the present application are described in detail above. The principles and embodiments of the present application are explained herein using specific examples, which are provided only to help understand the method and the core idea of the present application. It should be noted that, for those skilled in the art, it is possible to make several improvements and modifications to the present application without departing from the principle of the present application, and such improvements and modifications also fall within the scope of the claims of the present application.

Claims (10)

1. A three degree-of-freedom piezoelectric drive unit, comprising:
a base;
the three one-dimensional piezoelectric stacks are arranged on the upper surface of the base and are uniformly distributed along the circumferential direction;
the shell is arranged above the base, and the three one-dimensional piezoelectric stacks are positioned in the shell;
the guide membrane is arranged in the shell and is positioned above the driving ends of the three one-dimensional piezoelectric stacks;
the movable terminal is positioned on the upper surface of the guide membrane, the upper end of the movable terminal extends out of the shell, and the upper ends of the three one-dimensional piezoelectric stacks penetrate through the guide membrane to be in contact with the lower surface of the movable terminal;
the lower end of the flexible guide rod is connected with the base through an elastic piece, the upper end of the flexible guide rod is connected with the bottom of the movable terminal, and the elastic piece is used for applying pre-tightening force towards the one-dimensional piezoelectric stack to the movable terminal through the flexible guide rod;
three one-dimensional piezoelectric stacks are used for being deformed in a telescopic mode under corresponding driving voltage so as to control the movable terminal to generate translational motion in the z direction, rotary motion around the x axis and rotary motion around the y axis relative to the base.
2. The three-degree-of-freedom piezoelectric drive unit according to claim 1, wherein the elastic member includes a first pre-tightening disc spring, a through hole for the flexible guide rod to penetrate through is formed in the middle of the base, a cavity for accommodating the first pre-tightening disc spring is formed in the bottom of the base, the first pre-tightening disc spring is sleeved at the lower end of the flexible guide rod, a pre-tightening nut is connected to the lower end of the flexible guide rod in a threaded manner, and the pre-tightening nut is used for pressing the first pre-tightening disc spring on the top surface of the cavity.
3. The three-degree-of-freedom piezoelectric driving unit according to claim 2, wherein the flexible guide rod comprises a top threaded connection end, a thin rod and a bottom threaded connection end which are sequentially arranged from top to bottom, the top threaded connection end is connected with the movable terminal, and the pre-tightening nut is connected to the bottom threaded connection end.
4. The three-degree-of-freedom piezoelectric drive unit according to claim 1, wherein an outer side surface of the movable terminal is tapered from bottom to top.
5. The three-degree-of-freedom piezoelectric drive unit according to claim 1, wherein the casing includes a casing and a pressing ring, a lower end of the casing is connected to the base, and the pressing ring is configured to press the guide diaphragm against an upper end of the casing.
6. The three-degree-of-freedom piezoelectric drive unit according to claim 1, wherein an upper end of the one-dimensional piezoelectric stack is a spherical end, and the spherical end is in point contact with a lower surface of the movable terminal.
7. A planar piezoelectric actuator, comprising two sets of piezoelectric driving assemblies, wherein each set of piezoelectric driving assembly comprises a plurality of three-degree-of-freedom piezoelectric driving units according to any one of claims 1 to 6, the plurality of three-degree-of-freedom piezoelectric driving units are uniformly distributed along a circumferential direction, the planar piezoelectric actuator further comprises a rotor, the rotor is located above the movable terminal of the three-degree-of-freedom piezoelectric driving unit, and the two sets of piezoelectric driving assemblies alternately drive the rotor to generate stepping motion output under the friction coupling effect.
8. The planar piezoelectric actuator of claim 7, wherein the three-degree-of-freedom piezoelectric actuator unit of another group of the piezoelectric actuator assemblies is disposed between two adjacent three-degree-of-freedom piezoelectric actuator units of one group of the piezoelectric actuator assemblies.
9. The planar piezoelectric actuator of claim 8, further comprising a pre-tightening assembly and a supporting assembly, wherein each of the three-degree-of-freedom piezoelectric actuator units is located above the supporting assembly, and the pre-tightening assembly is configured to apply a pre-tightening force to the mover toward the three-degree-of-freedom piezoelectric actuator units.
10. The planar piezoelectric actuator according to claim 9, wherein the pre-tightening assembly comprises a pre-tightening screw, a pressing plate, a ball and a second pre-tightening disc spring, the pre-tightening screw sequentially penetrates through the supporting assembly and the mover from bottom to top, and the tail end of the pre-tightening screw is connected with the pressing plate, and the pre-tightening screw is used for pressing the second pre-tightening disc spring to the bottom of the supporting assembly; the bottom of the pressing plate is provided with a groove for containing the ball, and the ball is in contact with the upper surface of the rotor.
CN202210681520.8A 2022-06-16 2022-06-16 Three-degree-of-freedom piezoelectric drive unit and planar piezoelectric driver Pending CN115001308A (en)

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