CN116388609B - A Piezoelectric Actuator Driven by Inertial Stepping Principle - Google Patents

Abstract

The invention discloses a horizontal-rotational two-degree-of-freedom piezoelectric actuator driven based on the principle of inertial stepping, which belongs to the field of precision drive technology, and includes a base, slide grooves are processed on the guide rails on both sides of the base, and the upper surface of the slider is opposite to the Two mounting seats are arranged at the corners. The mounting seats are used to fix one end of the piezoelectric vibrator. Sliders are processed on both sides of the slider. The central hole in the middle part of the flexible structure cooperates with the connecting shaft of the moving rotor to realize the action output of the actuator. The flexible structure The two sides are connected to the two installation platforms through a plate-type flexible hinge, the other end of the piezoelectric vibrator is fixedly connected to the installation platform, the lower surface of the moving rotor is connected to the connecting shaft, and the external load is installed on the upper surface of the moving rotor. Driven by the signal, the bending drive plate-type flexible hinge deforms, and then drives the slider and the moving rotor to move along the extension direction of the chute and rotate around the connecting shaft, realizing the two degrees of freedom of the actuator's planar movement and rotation output.

Description

A Piezoelectric Actuator Driven by Inertial Stepping Principle

technical field

The invention belongs to the technical field of precision driving, and in particular relates to a piezoelectric actuator with two degrees of freedom of translation and rotation driven based on the principle of inertial stepping.

Background technique

With the rapid development of science and technology, high-precision drive technology is playing an increasingly important role in aerospace, micro-mechanical systems, bioengineering, optical engineering and other related technical fields. The existing high-precision actuators can be customized according to the type of drive unit Divided into magnetostrictive actuators, piezoelectric ceramic actuators, shape memory alloy actuators, etc. Among them, piezoelectric ceramic actuators have been widely used because of their advantages such as fast response, no electromagnetic interference, small size, and flexible control. At present, piezoelectric ceramic actuators are mainly divided into piezoelectric stack type and piezoelectric chip type. Among them, piezoelectric stack type has high driving voltage and small output displacement, while piezoelectric chip type can realize large deformation. Actuators with a single degree of freedom can no longer meet the many requirements of high-efficiency, precise, and intelligent drives in the high-tech field. Piezoelectric chip actuators provide new research ideas for the research of multi-degree-of-freedom piezoelectric actuators. The present invention proposes The flat-rotary two-degree-of-freedom piezoelectric actuator driven by the inertial stepping principle uses the piezoelectric vibrator as the driving unit. The structure is highly integrated, the control is flexible and it is not subject to electromagnetic interference.

Contents of the invention

The purpose of the present invention is to propose a horizontal-rotational two-degree-of-freedom piezoelectric actuator driven by the principle of inertial stepping. The piezoelectric vibrator is used as the driving unit, and combined with the large-scale deformation of the flexible hinge, it is a two-degree-of-freedom piezoelectric actuator. A reliable structure design idea is provided, which lays the foundation for the wide application of two-degree-of-freedom piezoelectric actuators.

A piezoelectric actuator driven by the principle of inertial stepping-rotation with two degrees of freedom, including a base, a slider, a piezoelectric vibrator, a flexible structure and a moving rotor;

There is a round hole in the center of the base, the base has a centrally symmetrical structure, and slide grooves are processed on the guide rails on both sides of the base;

Two mounting seats with threaded holes are arranged diagonally on the upper surface of the slider. The mounting seat is used to fix one end of the piezoelectric vibrator. There are sliding tables matching the chute on both sides of the slider, and a round hole is processed in the center of the bottom surface of the slider. ;

The central hole in the middle part of the flexible structure cooperates with the connecting shaft of the moving rotor to realize the action output of the actuator. The two sides of the flexible structure are connected to the two installation platforms through a plate-shaped flexible hinge. The other end is fixedly connected to the mounting table to ensure that the flexible structure, plate-type flexible hinge and mounting table can transmit deformation during the deformation process of the piezoelectric vibrator by the excitation signal;

The lower surface of the moving rotor is connected with a connecting shaft with an internal thread, and the connecting shaft is sequentially connected to the adjusting bolt through the central hole in the middle part of the flexible structure, the elastic ring, the gasket;

The external load is fixedly installed on the upper surface of the moving rotor by means of connecting parts, and the bending of the piezoelectric vibrator driven by different excitation signals is used to drive the plate-type flexible hinge to deform, thereby driving the slider and the moving rotor to move along the direction of the chute extension And the rotary motion centered on the connecting shaft realizes the motion output of the two degrees of freedom of the actuator's planar movement and rotation.

Furthermore, the piezoelectric vibrators are symmetrically distributed on both sides of the flexible structure, the sliding stages are symmetrically distributed on both sides of the slider, and the mounting stages are arranged diagonally on both sides of the flexible structure.

Furthermore, the piezoelectric vibrator is composed of two piezoelectric ceramic elements and a metal elastic sheet sandwiched between the piezoelectric ceramic elements.

Furthermore, it also includes a preloading mechanism, which is composed of a preloading rod A, a preloading screw, a preloading bolt and a preloading rod B, and the two sides of the upper surface of the base are symmetrically arranged with the preloading rod A and the preloading rod B. The mounting hole for the tightening rod B, the pre-tightening rod A and the pre-tightening rod B are fixed and installed on the base through the pre-tightening bolts in turn, and the middle part of the pre-tightening rod A and the pre-tightening rod B is processed with a threaded hole for installing the pre-tightening screw. The end of the tightening screw contacts the sliding table, and the pre-tightening force of the sliding table in the guide rail chute is regulated by adjusting the tightening degree of the pre-tightening screw.

Furthermore, the flexible structure, the installation platform and the plate-shaped flexible hinge are integrally processed from a whole piece of elastic metal material.

Furthermore, the elastic metal material is quenched 65Mn spring steel.

Furthermore, the upper surface of the moving rotor is processed with threaded holes for fixing external loads.

Furthermore, the diameter of the connecting shaft is smaller than the diameter of the central hole of the flexible structure, the connecting shaft and the central hole of the flexible structure are in a transition fit, and the outer surface of the connecting shaft is in frictional contact with the central hole in the middle part of the flexible structure. Controlling the tightening degree of the adjusting bolt can adjust the pre-tightening friction force between the moving rotor and the flexible structure.

Compared with the prior art, the present invention has the following beneficial effects:

1. The present invention uses the bending deformation of two piezoelectric vibrators under the excitation of out-of-phase sawtooth wave driving voltage to drive the slider and the moving rotor to move along the extending direction of the chute and rotate around the connecting shaft, and finally complete the planar Motion output with two degrees of freedom of movement and rotation;

2. The structure of the present invention has high integration and flexible control. The piezoelectric vibrator is used as the drive unit, and the motion output can be realized with the flexible structure. The degree of integration is high, the structure is simple and the control is flexible. Sawtooth wave drive signal, the moving rotor can realize linear motion along the extending direction of the chute, by applying the opposite sawtooth wave drive signal to the two piezoelectric vibrators, the moving rotor can complete the rotary motion centered on its connecting shaft. When the piezoelectric vibrator adopts the reverse sawtooth wave drive signal, the moving rotor can realize the linear motion or rotational motion in the opposite direction;

3. The present invention has good application prospects in technical fields such as optical instruments, integrated circuits, precision and ultra-precision processing, and micro-robots. The two-degree-of-freedom inertial piezoelectric actuator with a highly integrated structure and flexible control is a multi-degree-of-freedom piezoelectric actuator. The design of the actuator provides a new idea and lays the foundation for the wide application of the piezoelectric actuator in the field of precision motor drive.

Description of drawings

Fig. 1 is the three-dimensional structure schematic diagram of the present invention;

Fig. 2 is the top view of the present invention;

Figure 3 is a top view of the moving rotor not connected to the present invention;

Fig. 4 is the exploded schematic view of the present invention;

Fig. 5 is an excitation voltage signal waveform diagram of the present invention;

6 is a schematic diagram of bending deformation of the piezoelectric vibrator of the present invention under different excitation voltages;

Fig. 7 is the driving principle diagram when the present invention produces rotational angular displacement output;

Fig. 8 is the driving principle diagram when the present invention produces linear displacement output;

Fig. 9 is a three-dimensional structural schematic diagram of the connection between the flexible structure, the mounting platform and the plate-type flexible hinge;

Fig. 10 is a schematic perspective view of the connection of the slider, the mounting seat and the slide table.

In the figure: 1, slider; 1-1, mounting seat; 1-2, sliding table; 2, flexible structure; 2-1, mounting table; 2-2, plate-shaped flexible hinge; 3, piezoelectric vibrator A; 4. Base; 5. Preload rod A; 6. Preload screw; 7. Preload bolt; 8. Moving rotor; 9. Fixing bolt; 10. Preload rod B; 11. Piezoelectric vibrator B; 12. Elasticity Ring; 13. Gasket; 14. Adjusting bolt.

Detailed ways

Embodiment one of the present invention,

Referring to Fig. 1 to Fig. 4, Fig. 9 and Fig. 10, a piezoelectric actuator driven by the principle of inertial stepping-rotation with two degrees of freedom includes a base 4, a slider 1, a piezoelectric vibrator, a preload mechanism, a flexible Structure 2 and moving rotor 8;

There is a round hole in the center of the base 4, which facilitates the assembly between the moving rotor 8 and the flexible structure 2. The base 4 has a centrally symmetrical structure, and mounting holes are symmetrically arranged on both sides of the upper surface of the base 4. Slide grooves are processed on the guide rails;

Two mounting seats 1-1 with threaded holes are arranged diagonally on the upper surface of the slider 1. The mounting seat 1-1 is used to fix one end of the piezoelectric vibrator, and the two sides of the slider 1 are processed with a sliding table 1 that matches the chute. -2, a round hole is processed in the center of the bottom surface of the slider 1, which facilitates the assembly between the movable rotor 8 and the flexible structure 2, and the slider 1 as a whole can move along the extending direction of the chute;

The piezoelectric vibrator is composed of two piezoelectric ceramic elements and a metal elastic sheet sandwiched between the piezoelectric ceramic elements. Driven by different electrical excitation signals, the piezoelectric vibrator can produce bending deformation;

The preloading mechanism is composed of preloading rod A5, preloading screw 6, preloading bolt 7 and preloading rod B10, wherein preloading rod A5 and preloading rod B10 are fixed and installed on the base 4 through preloading bolt 7 in turn, and the preloading The middle part of the tightening rod A5 and the pre-tightening rod B10 is processed with a threaded hole for installing the pre-tightening screw 6, and the end of the pre-tightening screw 6 touches the sliding table 1-2, and the tightening degree of the pre-tightening screw 6 is adjusted to control the position of the sliding table 1-2. Preload in the rail runners;

The middle part of the flexible structure 2 is circular. The center hole of the middle part of the flexible structure 2 cooperates with the connecting shaft of the moving rotor 8 to realize the action output of the actuator. Table 2-1, threaded holes are machined in the center of the mounting table 2-1, and the other end of the piezoelectric vibrator is fixedly connected to the mounting table 2-1 through the fixing bolt 9, so as to ensure the flexible structure of the piezoelectric vibrator when it is deformed by the excitation signal. 2. Plate shape The flexible hinge 2-2 and the mounting table 2-1 can transmit deformation; in order to ensure good deformation accuracy between the flexible structure 2, the mounting table 2-1 and the plate-type flexible hinge 2-2, the flexible structure 2, the mounting table 2- 1 and plate-type flexible hinge 2-2 are integrally processed from a whole piece of elastic metal material, and the specific elastic metal material can be: 65Mn spring steel after quenching treatment;

The moving rotor 8 is a disk-shaped structure, the lower surface of the moving rotor 8 is connected with a connecting shaft with internal threads, and the upper surface of the moving rotor 8 is processed with threaded holes for fixing external loads, and the connecting shaft passes through the middle part of the flexible structure 2 in turn. The central hole, the elastic ring 12, the gasket 13 are connected with the adjusting bolt 14, wherein the diameter of the connecting shaft is slightly smaller than the diameter of the central hole of the flexible structure 2, and the connecting shaft and the central hole of the flexible structure 2 are a transition fit to ensure that the outer surface of the connecting shaft is in contact with the flexible structure. The center hole in the middle part of the structure 2 is in frictional contact. By controlling the tightening degree of the adjusting bolt 14, the purpose of adjusting the pre-tightening friction force between the movable rotor 8 and the flexible structure 2 can be achieved. The failure of the actuator caused by the loosening of the bolt 14 provides continuous pretension for the connection between the moving rotor 8 and the flexible structure 2, further improving the reliability of the actuator;

The external load can be fixedly installed on the upper surface of the moving rotor 8 by means of connectors, and the deformation of the plate-type flexible hinge 2-2 is driven by the bending of the piezoelectric vibrator driven by different excitation signals, thereby driving the slider 1 and the moving rotor 8 to realize The movement along the extension direction of the chute and the rotational movement centered on the connecting shaft realize the motion output of the two degrees of freedom of the actuator's planar movement and rotation.

In the first embodiment, the piezoelectric vibrator and slide table 1-2 adopt a symmetrical installation method, and the installation table 2-1 adopts a diagonal installation method, and two piezoelectric vibrators are used to drive the flexible structure under the drive of out-of-phase excitation signals. 2. The mounting table 2-1 and the plate-type flexible hinge 2-2 are deformed, and then the moving rotor 8 is pushed to produce a linear displacement output along the extending direction of the chute and a rotational movement with the center line of the moving rotor 8 as the rotation axis, thereby realizing the execution The two-degree-of-freedom motion output of the device. The moving rotor 8 and the flexible structure 2 are assembled together by means of an elastic ring 12, a gasket 13 and an adjusting bolt 14, which avoids affecting the overall motion output efficiency of the actuator due to looseness during the long-term working process of the actuator, and further improves the performance of the actuator. work reliability.

Both the piezoelectric vibrator A3 and the piezoelectric vibrator B11 use the sawtooth wave voltage as the excitation signal. When the out-of-phase sawtooth wave voltage signal shown in Figure 5(a) is applied to the piezoelectric vibrator A3 and the piezoelectric vibrator B11 at the same time, the moving rotor 8 It can produce a rotational angular displacement output centered on the connecting axis. When the piezoelectric vibrator A3 is applied with the out-of-phase sawtooth wave voltage signal shown in Figure 5(b) and the piezoelectric vibrator B11 is applied, the moving rotor 8 It can produce linear displacement output along the extending direction of the chute.

As shown in Figure 6, the lower end of the piezoelectric vibrator is fixed, and the upper end of the piezoelectric vibrator is the movable end. When the piezoelectric vibrator is bent to the right, it is the positive direction, and when the piezoelectric vibrator is bent to the left, it is the negative direction. The concrete work process of invention is as follows:

1. As shown in Figure 7, when the out-of-phase sawtooth wave voltage signal shown in Figure 5(a) is applied to the piezoelectric vibrator A3 and the piezoelectric vibrator B11 at the same time, the initial state voltage of the two piezoelectric vibrators is 0, In the original long state, the actuator has no motion output at this time. When the voltage slowly reaches the U/-U value at the same step-up/step-down speed, the bending deformation of the two piezoelectric vibrators along the extending direction of the chute is L. Here During the process, the mounting table 2-1 of the flexible structure 2 also produces a displacement L, and the plate-shaped flexible hinge 2-2 is also bent and deformed under the push of the two piezoelectric vibrators and the mounting table 2-1. The flexible hinges 2-2 jointly generate a clockwise moment on the middle part of the flexible structure 2, and the middle part of the flexible structure 2 generates a rotational movement around the central axis under the action of the torque. At this time, the load follows the joint movement of the middle part of the flexible structure 2. The clockwise rotation angle is θ1. When the driving voltage rapidly drops/rises from U/-U to 0, the two piezoelectric vibrators quickly return to their initial state after losing the voltage excitation, and then drive the installation table 2-1, the plate-type flexible hinge 2-2 and the middle of the flexible structure 2 Partially returns to the original position, the moving rotor 8 and the load rotate counterclockwise by an angle θ2 under the joint action of its own gravity inertia and the inner wall friction of the central hole in the middle part of the flexible structure 2, and is driven by a sawtooth wave electrical signal. The rotor 8 produces a clockwise angular displacement (θ1-θ2) relative to the middle part of the flexible structure 2, that is, the output precision of the rotational angular displacement of the piezoelectric actuator is (θ1-θ2).

If this process is repeated continuously, the actuator can realize a large-stroke stepping rotation angular displacement output clockwise around the Z axis. By applying a reverse sawtooth wave drive signal to the piezoelectric vibrator A3 and piezoelectric vibrator B11, the actuator can Realize the rotation angle displacement output in the counterclockwise direction around the Z axis.

2. As shown in Figure 8, when the out-of-phase sawtooth wave voltage signal shown in Figure 5(b) is applied to the piezoelectric vibrator A3 and the piezoelectric vibrator B11 is applied to the out-of-phase sawtooth wave voltage signal shown in Figure 5(b), the initial voltage of the two piezoelectric vibrators is 0, in the original long state, when the driving voltage of the piezoelectric ceramics on both sides of the piezoelectric vibrator A3 and the piezoelectric vibrator B11 slowly increases to U and slowly decreases to -U, the piezoelectric vibrator A3 undergoes bending deformation in the positive direction. The table 2-1 and the plate-type flexible hinge 2-2 generate a horizontal force to the left on the flexible structure 2, and the piezoelectric vibrator B11 undergoes negative bending deformation, and the flexible structure 2 is also exerted by the mounting table 2-1 and the plate-type flexible Structure 2 generates a horizontal force to the left. Under the joint action of the two piezoelectric vibrators, the flexible mechanism 2 and the moving rotor 8 produce a linear displacement L1 to the left. During this process, the slider 1 remains in a static state. When the piezoelectric vibrator A3 and the When the voltage signal of the piezoelectric ceramics on both sides of the electric vibrator B11 quickly returns to 0, the two piezoelectric vibrators quickly return to their original lengths, and the moving rotor 8 and the load tend to remain static under the action of inertia, but under the action of the two piezoelectric vibrators Move the distance L2 to the right. At this time, the slider 1 moves to the left along the extension direction of the chute under the drive of the two piezoelectric vibrators. The distance is (L1-L2), that is, the linear displacement output accuracy of the actuator is (L1-L2) .

If this process is repeated continuously, the actuator can realize a large-stroke linear displacement output along the positive direction of the Y-axis. By applying a reverse sawtooth wave drive signal to each piezoelectric vibrator, the actuator can realize a linear displacement output along the negative direction of the Y-axis. Large stroke step linear displacement output.

The piezoelectric actuator undergoes an action of the same sawtooth wave waveform. Driven by two piezoelectric vibrators, the moving rotor 8 can generate a clockwise or counterclockwise rotation angular displacement output around its connecting axis. Driven by different sawtooth wave waveform signals Next, the movable rotor 8 can produce a linear displacement output to the left or right along the extending direction of the chute. By repeating this process repeatedly, the piezoelectric actuator can realize two degrees of freedom motion output of translation and rotation.

Claims (7)

1. The utility model provides a flat-change two degrees of freedom piezoelectric actuator based on inertia stepping principle drive which characterized in that: comprises a base (4), a sliding block (1), a piezoelectric vibrator, a flexible structure (2) and a movable rotor (8);

the center of the base (4) is provided with a round hole, the base (4) is in a central symmetrical structure, and guide rails at two sides of the base (4) are provided with sliding grooves;

two mounting seats (1-1) with threaded holes are diagonally arranged on the upper surface of the sliding block (1), the mounting seats (1-1) are used for fixing one end of the piezoelectric vibrator, sliding tables (1-2) matched with sliding grooves are machined on two sides of the sliding block (1), and a round hole is machined in the center of the bottom surface of the sliding block (1);

the central hole in the middle of the flexible structure (2) is matched with the connecting shaft of the movable rotor (8) to realize the action output of the actuator, two sides of the flexible structure (2) are connected with two mounting tables (2-1) through plate-type flexible hinges (2-2), threaded holes are machined in the centers of the mounting tables (2-1), the other ends of the piezoelectric vibrators are fixedly connected with the mounting tables (2-1) through fixing bolts (9), and the flexible structure (2), the plate-type flexible hinges (2-2) and the mounting tables (2-1) can be guaranteed to transmit deformation in the deformation process of the excited signals of the piezoelectric vibrators;

the lower surface of the movable rotor (8) is connected with a connecting shaft with internal threads, and the connecting shaft is connected with an adjusting bolt (14) through a central hole, an elastic ring (12) and a gasket (13) in the middle part of the flexible structure (2) in sequence;

the external load is fixedly arranged on the upper surface of the movable rotor (8) in a connecting way by adopting a connecting piece, and the bending driving plate type flexible hinge (2-2) driven by the piezoelectric vibrator under different excitation signals is utilized to deform, so that the sliding block (1) and the movable rotor (8) are driven to realize movement along the extending direction of the sliding chute and rotary movement taking a connecting shaft as the center, and the actuator realizes movement output of two degrees of freedom of plane movement and rotation;

the piezoelectric vibrators are symmetrically distributed on two sides of the flexible structure (2), the sliding tables (1-2) are symmetrically distributed on two sides of the sliding blocks (1), and the mounting tables (2-1) are diagonally arranged on two sides of the flexible structure (2).

2. The inertial stepping principle driven two-degree-of-freedom piezoelectric actuator of claim 1, wherein: the piezoelectric vibrator is composed of two piezoelectric ceramic elements and a metal elastic sheet sandwiched between the piezoelectric ceramic elements.

3. The inertial stepping principle driven two-degree-of-freedom piezoelectric actuator of claim 1, wherein: still include pretension mechanism, pretension mechanism comprises pretension pole A (5), pretension screw (6), pretension bolt (7) and pretension pole B (10) jointly, base (4) upper surface both sides symmetrical arrangement have with pretension pole A (5) and pretension pole B (10) complex mounting hole, pretension pole A (5) and pretension pole B (10) loop through pretension bolt (7) fixed mounting on base (4), pretension pole A (5) and pretension pole B (10) mid portion processing have the screw hole of installation pretension screw (6), pretension screw (6) terminal contact slip table (1-2), through adjusting the tightening degree of pretension screw (6) and then regulate and control slip table (1-2) pretension force in the guide rail spout.

4. The inertial stepping principle driven two-degree-of-freedom piezoelectric actuator of claim 1, wherein: the flexible structure (2), the mounting table (2-1) and the plate-type flexible hinge (2-2) are integrally processed by a whole piece of elastic metal material.

5. The inertial stepping principle driven two-degree-of-freedom piezoelectric actuator of claim 4, wherein: the elastic metal material is 65Mn spring steel subjected to quenching treatment.

6. The inertial stepping principle driven two-degree-of-freedom piezoelectric actuator of claim 1, wherein: the upper surface of the movable rotor (8) is provided with a threaded hole for fixing external load.

7. The inertial stepping principle driven two-degree-of-freedom piezoelectric actuator of claim 1, wherein: the diameter of the connecting shaft is smaller than that of a central hole of the flexible structure (2), the connecting shaft is in transition fit with the central hole of the flexible structure (2), and the pre-tightening friction force between the movable rotor (8) and the flexible structure (2) can be adjusted by controlling the tightening degree of the adjusting bolt (14).