CN115955141A - Integrated two-degree-of-freedom stepper actuator based on piezoelectric drive - Google Patents

Abstract

The application discloses step-by-step executor of two degrees of freedom of integrated form based on piezoelectricity drive relates to piezoelectric motor technical field, including stator, guide rail, actuating mechanism and moving the rotor four bibliographic categories branch, sliding guide includes guide rail A and guide rail B, guide rail A and guide rail B symmetry set up on the flexible mechanism lower surface, guide rail A, guide rail B and flexible mechanism lower surface constitute the guide rail spout, the stator assemble in the guide rail spout, actuating mechanism includes flexible mechanism, piezoceramics A and piezoceramics B, flexible mechanism is including moving rotor mount pad, board type flexible hinge, the flexible hinge of positive circle type and flexible installation frame. The invention utilizes the inverse piezoelectric effect of the two piezoelectric ceramics to push the flexible mechanism to generate periodic deformation, and further drives the movable rotor to generate linear displacement and rotation angle displacement output, thereby realizing linear-rotation two-degree-of-freedom motion.

Description

Integrated two-degree-of-freedom stepper actuator based on piezoelectric drive

technical field

The invention belongs to the technical field of piezoelectric motors, in particular to an integrated two-degree-of-freedom stepping actuator based on piezoelectric drive.

Background technique

With the gradual emergence of the application potential of single-degree-of-freedom piezoelectric actuators in aerospace, optical instruments, biomedicine, integrated circuits and other technical fields, multi-degree-of-freedom piezoelectric actuators have also become a hot research topic for many researchers. Traditional multi-degree-of-freedom actuators are mainly driven by electromagnetic motors, which have low positioning accuracy and electromagnetic interference. Compared with traditional multi-degree-of-freedom actuators, multi-degree-of-freedom piezoelectric actuators based on the inverse piezoelectric effect of piezoelectric materials have many advantages such as simple structure, fast response, high precision, and no magnetic field interference. In addition, traditional multi-degree-of-freedom actuators require multiple parts to work together, which is difficult to control, and the cost of micro-actuators that realize power output through mechanical structures is high.

Contents of the invention

The present invention aims at the problems that the traditional multi-degree-of-freedom actuator has a complex structure, occupies a large space, is prone to electromagnetic interference, is difficult to control, and has a high cost of micro-actuator that realizes power output through a mechanical structure. An integrated two-degree-of-freedom stepping actuator based on piezoelectric drive is proposed, which uses piezoelectric ceramics as the driving unit according to the stepping principle, and can realize linear motion along the direction of the guide rail and rotational motion around the rotor shaft. The output accuracy of the actuator can be controlled by adjusting the tightening degree of the adjusting bolt.

The specific technical solution is: an integrated two-degree-of-freedom stepping actuator based on piezoelectric drive, including four parts: stator, sliding guide rail, driving mechanism and moving rotor.

The sliding guide rail includes a guide rail A and a guide rail B, and the guide rail A and the guide rail B are arranged symmetrically on the lower surface of the flexible mechanism, the guide rail A, the guide rail B and the lower surface of the flexible mechanism constitute a guide rail chute, and the stator is assembled on Inside the guide rail chute;

The driving mechanism includes a flexible mechanism, piezoelectric ceramics A and piezoelectric ceramics B, and the flexible mechanism includes a moving rotor mounting seat, a plate-shaped flexible hinge, a perfect circular flexible hinge and a flexible installation frame. One end of the flexible installation frame Two pairs of plate-type flexible hinges are installed on the inner side, and each pair of plate-type flexible hinges forms a piezoelectric ceramic installation groove. The two pairs of plate-type flexible hinges are respectively connected to the moving rotor mounting seat through a perfect circular on the moving rotor mounting base.

Further, the two piezoelectric ceramic mounting grooves are distributed symmetrically with respect to the central axis of the flexible mechanism, and are respectively located on both sides of the moving rotor mounting seat.

Further, the flexible mechanism is integrally processed from a whole piece of elastic metal material.

Further, the moving rotor is a part with a rotating shaft, and the moving rotor is installed on the moving rotor mounting seat through the rotating shaft, and the rotating shaft of the moving rotor is in a transition fit with the center hole of the moving rotor mounting seat.

Further, the rotating shaft of the moving rotor passes through the gasket, the central hole of the moving rotor rotor mounting seat, the gasket, the elastic ring and another gasket in sequence, and then cooperates and locks with the nut.

Further, an adjusting bolt is installed on the outer surfaces of the guide rail A and the guide rail B respectively.

Further, the drive mechanism also includes a pre-tightening washer A, a pre-tightening bolt A, a pre-tightening washer B and a pre-tightening bolt B, and the pre-tightening washer A and the pre-tightening bolt A are used to adjust the piezoelectric ceramic A The pre-tightening force of the piezoelectric ceramic B is adjusted by the pre-tightening washer B and the pre-tightening bolt B.

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

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

1. The integrated two-degree-of-freedom stepping actuator based on piezoelectric drive of the present invention is specially designed to include a flexible mechanism including a moving rotor mounting seat, a plate-type flexible hinge, a perfect circular flexible hinge and a flexible mounting frame, and to cooperate with the stator The slideway of the guide rail uses the sequential strain of two piezoelectric ceramics under the excitation of the same-phase and out-of-phase sawtooth wave driving voltages to push two pairs of plate-type flexible hinges to achieve periodic expansion and contraction deformation, and then through two perfect circular flexible hinges Drive the moving rotor mounting seat to produce linear displacement or rotate around its center hole. Under the action of the friction force or friction torque of the center hole on the moving rotor shaft, the moving rotor can realize linear-rotation two degrees of freedom;

2. By applying a sawtooth wave drive signal of slow boosting and rapid voltage reduction in phase to two symmetrically arranged piezoelectric ceramics, the moving rotor can realize linear motion along the forward direction of the stator, and by applying out-of-phase to the symmetrically arranged piezoelectric ceramics When the sawtooth wave drive signal is used, the moving rotor can complete the rotary motion centered on its rotating shaft. When the opposite sawtooth wave drive signal is used for the two piezoelectric ceramics that work together, the moving rotor can achieve linear motion in the opposite direction. or rotary motion;

3. Using piezoelectric ceramics as the driving unit, the power integration degree is high, the structure is simple and easy to control flexibly, the influence of electromagnetic interference can be eliminated, and the reliability of the actuator is high;

4. The present invention has good application prospects in technical fields such as aerospace, optical instruments, biomedicine, integrated circuits, etc. The motion output of two degrees of freedom of linear-rotation further expands the application of multi-degree-of-freedom piezoelectric actuators in precision motor drives. range of applications in the field.

Description of drawings

Figure 1 is a schematic diagram of the three-dimensional structure of an integrated two-degree-of-freedom stepper actuator based on piezoelectric drive;

Figure 2 is a top view of the integrated two-degree-of-freedom stepper actuator based on piezoelectric drive;

Figure 3 is a schematic diagram of the assembly of the moving rotor and the flexible mechanism of the integrated two-degree-of-freedom stepping actuator based on piezoelectric drive;

Fig. 4 is a top view of the flexible mechanism of the integrated two-degree-of-freedom stepping actuator based on piezoelectric drive described in Fig. 1;

Figure 5 is a driving signal waveform diagram of an integrated two-degree-of-freedom stepper actuator based on piezoelectric drive, where (a) is an in-phase sawtooth wave signal, and (b) is an out-of-phase sawtooth wave signal;

Figure 6 is a schematic diagram of the driving principle when the integrated two-degree-of-freedom stepper actuator based on piezoelectric drive produces linear displacement output;

Fig. 7 is a schematic diagram of the driving principle when the integrated two-degree-of-freedom stepper actuator based on the piezoelectric drive generates the output of the rotation angle displacement;

In the figure: 1. Pre-tightening bolt A; 2. Pre-tightening gasket A; 3. Piezoelectric ceramic A; 4. Adjusting bolt A; 5. Guide rail A; 6. Stator; 7. Moving rotor; 8. Flexible mechanism; 9. Piezoelectric ceramic B; 10. Pre-tightening gasket B; 11. Guide rail B; 12. Pre-tightening bolt B; 13. Adjusting bolt B; 14. Moving rotor mounting seat; 15. Plate-type flexible hinge; 16. Circular flexible hinge; 17. Elastic ring; 18. Gasket; 19. Flexible installation frame.

Detailed ways

In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention clearer, the present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described here are only used to explain the present invention, not to limit the present invention.

Example 1

Referring to FIG. 1 to FIG. 4 , the integrated two-degree-of-freedom stepper actuator based on piezoelectric drive described in this embodiment includes four parts: a stator 6 , a sliding guide rail, a driving mechanism and a moving rotor 7 .

The stator 6 can be fixedly connected to the workbench through bolts, and plays a guiding role for the actuator as a whole;

The sliding guide rail includes guide rail A5 and guide rail B11, wherein guide rail A5 and guide rail B11 are symmetrically fixed on the lower surface of the flexible mechanism 8 by bolts, the guide rail A5, guide rail B11 and the lower surface of the flexible mechanism 8 form a guide rail chute, and the stator 6 is assembled in the guide rail chute Inside, the actuator as a whole can output a linear displacement along the extension direction of the stator 6 under the action of the sliding guide rail. An adjusting bolt A4 is installed on the outer surface of the guide rail A5, and an adjusting bolt B13 is installed on the outer surface of the guide rail B11. The guide rail A5 and the adjusting bolt A4 Working together, the guide rail B11 and the adjusting bolt B13 work together. During the working process, the friction between the stator 6 and the guide rail can be controlled by adjusting the positions of the adjusting bolt A4 and the adjusting bolt B13, thereby adjusting the linear displacement step of the actuator. The role of precision.

As shown in Fig. 1, the driving mechanism includes a flexible mechanism 8, a piezoelectric ceramic A3, a pre-tightening washer A2, a pre-tightening bolt A1, a piezoelectric ceramic B9, a pre-tightening washer B10 and a pre-tightening bolt B12. As shown in Figure 4, the flexible mechanism 8 includes a moving rotor mounting base 14, a plate-shaped flexible hinge 15, a perfect circular flexible hinge 16 and a flexible installation frame 19, the flexible installation frame 19 is a square frame, and the guide rail A5 and the guide rail B11 are respectively fixed. on the lower surface of the frame on both sides of the flexible installation frame 19. Two pairs of plate-type flexible hinges 15 are installed on the inner side of one end of the flexible installation frame 19, and each pair of plate-type flexible hinges 15 forms a piezoelectric ceramic installation groove, and the two piezoelectric ceramic installation grooves are symmetrically distributed about the central axis of the flexible mechanism 8. The opposite plate-type flexible hinges 15 are respectively connected to the moving rotor mounting base 14 through a perfect circular flexible hinge 16, that is, one end of the two piezoelectric ceramic mounting grooves is connected to the flexible mounting frame 19, and the other end is connected through two perfect circular flexible hinges. 16 is connected to the moving rotor mounting base 14, and two pairs of plate-type flexible hinges 15 are respectively located on both sides of the moving rotor mounting base 14; the piezoelectric ceramic A3 is installed in the mounting groove on the right side of the flexible mechanism 8, and can be connected by the pre-tightening gasket A2 and the pre-tightening bolt A1 to adjust the initial pre-tightening force of the piezoelectric ceramic A3, the piezoelectric ceramic B9 is installed in the installation groove on the left side of the flexible mechanism 8, and the piezoelectric ceramic B9 can be adjusted through the pre-tightening washer B10 and the pre-tightening bolt B12 initial preload.

Furthermore, in order to ensure better deformation accuracy of the plate-type flexible hinge 15, the perfect circular flexible hinge 16, and the flexible installation frame 19, the entire flexible mechanism 8 is integrally processed from a whole piece of elastic metal material, and the elastic metal material It is 65Mn spring steel after quenching treatment.

The moving rotor 7 is installed on the moving rotor mounting seat 14, and the specific connection methods can be selected from threaded connection, clamping connection, sleeve connection and other connection methods.

Specifically, the moving rotor 7 is a part with a rotating shaft as a whole, preferably a disc part with a rotating shaft, wherein the end of the rotating shaft away from the disc is processed with threads, as shown in Figure 3, the rotating shafts of the moving rotor 7 pass through in turn during assembly. The gasket 18, the center hole of the moving rotor mounting seat 14, the gasket 18, the elastic ring 17 and another gasket 18 are finally locked together with the nut, wherein the rotating shaft of the moving rotor 7 and the center hole of the moving rotor mounting seat 14 are transitional Cooperate, the diameter of the central hole is slightly larger than the diameter of the rotating shaft to ensure frictional contact between the outer surface of the rotating shaft and the inner surface of the central hole. In addition, the pre-tightening friction force between the moving rotor 7 and the moving rotor mounting seat 14 can be adjusted by adjusting the tightening degree of the nut. The application of the elastic ring 17 ensures a continuous friction force between the two, avoiding long-term damage to the actuator. During the working process, the overall motion output efficiency of the actuator is affected by the problem of nut looseness, which further improves the output accuracy of the actuator's rotational angular displacement.

The load can be fixedly installed in the threaded hole on the upper surface of the disc of the moving rotor 7 through bolts, and the linear displacement output along the extending direction of the stator 6 can be realized by utilizing the mutual cooperation of the driving mechanism, the sliding guide rail and the moving rotor 7 or the rotating shaft of the moving rotor 7 as the The output of the rotational angular displacement of the center finally realizes the two-degree-of-freedom motion of the integrated stepper actuator.

In this embodiment, the driving mechanism is divided into two parts, A and B, which are arranged symmetrically. The piezoelectric ceramic mounting grooves on the left and right sides of the driving mechanism have exactly the same structure, and are symmetrically distributed with the centerline of the flexible mechanism 8 as the axis. Driven by different driving signals, the piezoelectric ceramics A3 and piezoelectric ceramics B9 can drive the flexible installation frame 19, the plate-shaped flexible hinge 15, the perfect circular flexible hinge 16, and the moving rotor mounting seat to output linear motion along the length direction of the stator 6 or in a The rotating shaft of the moving rotor 7 rotates around the axis as the center, so that under the action of friction force or friction torque, the moving rotor 7 is driven to realize the motion output of two degrees of freedom of linear and rotation. The moving rotor 7 and the flexible mechanism 8 are assembled together by means of bolts, gaskets 18 and elastic rings 17, which avoids affecting the overall motion output efficiency of the actuator due to nut looseness during the long-term working process of the actuator, and further improves the rotation of the actuator. The output accuracy of the angular displacement.

Example 2

This embodiment will be specifically described with reference to FIG. 5 to FIG. 7 . This embodiment is a further description of the piezoelectric-driven integrated two-degree-of-freedom stepping actuator described in Embodiment 1. In this embodiment, both piezoelectric ceramics A3 and piezoelectric ceramics B9 use a sawtooth wave voltage drive signal. When the in-phase sawtooth wave signal shown in Figure 5(a) is applied to piezoelectric ceramics A3 and piezoelectric ceramics B9 at the same time, the moving rotor 7 will realize the linear displacement output along the advancing direction of the stator 6, and the specific working principle is shown in Figure 6; When piezoelectric ceramics A3 and piezoelectric ceramics B9 are applied with the out-of-phase sawtooth wave signal shown in Figure 5(b), the moving rotor 7 will realize the output of the rotation angle displacement centered on its rotating shaft. The specific working principle is shown in Figure 7.

As shown in Fig. 6-Fig. 7, the specific work process of the present invention is as follows:

1. As shown in Figure 6, when the in-phase sawtooth wave driving voltage excitation signal shown in Figure 5(a) is applied to both piezoelectric ceramics A3 and piezoelectric ceramics B9, the initial state voltage of the two piezoelectric ceramics is 0, and they are in the original state. In the long state, when the voltage slowly rises to U, the two piezoelectric ceramics slowly extend the distance L1 under the inverse piezoelectric effect. At this time, the two pairs of plate-shaped flexible hinges 15 are deformed and stretched For a long distance L1, the moving rotor mounting base 14 produces a linear displacement L1 driven by the plate-shaped flexible hinge 15 and the perfect circular flexible hinge 16, and the moving rotor 7 generates a linear displacement of a distance L1 under the push of the moving rotor mounting base 14. When the driving voltage drops sharply to 0, the two piezoelectric ceramics lose the voltage excitation and quickly return to their original lengths, and the plate-shaped flexible hinge 15 returns to its original position without the driving force of the piezoelectric ceramics. Under the action, a small displacement L2 is generated backward. After being driven by a sawtooth waveform signal, the moving rotor 7 generates a linear displacement (L1-L2) relative to the stator 6, that is, the piezoelectric actuator outputs a linear displacement with a step accuracy of (L1-L2 ), the pre-tightening friction force between the sliding guide rail and the stator 6 can be controlled by adjusting the tightening degree of the adjusting bolt A4 and the adjusting bolt B13, so as to further adjust the linear displacement output accuracy of the actuator. By applying a reverse sawtooth wave drive signal to the piezoelectric ceramics A3 and piezoelectric ceramics B9, the moving rotor 7 can generate a displacement output moving in the opposite direction;

2. As shown in Figure 7, when the out-of-phase sawtooth wave signal shown in Figure 5(b) is applied to piezoelectric ceramic A3 and piezoelectric ceramic B9, the initial state signal voltage of piezoelectric ceramic A3 is 0, and the initial state signal voltage of piezoelectric ceramic B9 The state signal voltage is 0, and both are in the original long state. As the driving voltage of piezoelectric ceramic A3 gradually increases to U, the driving voltage of piezoelectric ceramic B9 gradually decreases to -U. Under the inverse piezoelectric effect of piezoelectric ceramics, the displacement output of piezoelectric ceramic A3 is L, and piezoelectric ceramic B9 The output displacement is -L, that is, the shortening amount of the piezoelectric ceramic is L. During this process, the moving rotor mounting seat 14 is driven by the torque generated by the deformation of the piezoelectric ceramic mounting groove to rotate counterclockwise by an angle θ ₁ along its central axis, and the moving rotor 7 follows the rotating angle θ ₁ of the mounting seat under the action of inertia. When the driving voltage of piezoelectric ceramic A3 is suddenly reduced to 0 and the driving voltage of piezoelectric ceramic B9 is suddenly increased to 0, piezoelectric ceramic A3 and piezoelectric ceramic B9 quickly return to their original lengths, and the moving rotor mounting base 14 is also flexible in the plate shape. The hinge 15 and the perfect circular flexible hinge 16 are driven back to the initial position, and the rotating shaft of the moving rotor 7 rotates clockwise by an angle θ ₂ under the friction of the center hole of the moving rotor mounting base 14 . Driven by a sawtooth waveform signal, the moving rotor 7 produces a counterclockwise angular displacement (θ ₁ -θ ₂ ) relative to the moving rotor mounting base 14, that is, the step accuracy of the output rotational angular displacement of the piezoelectric actuator is (θ ₁ -θ ₂ ). By applying a reverse saw-tooth wave drive signal to the piezoelectric ceramics A3 and piezoelectric ceramics B9, the movable rotor 7 can realize the clockwise rotation angular displacement output around its rotation axis.

The piezoelectric actuator moves through an in-phase sawtooth wave waveform. Driven by two piezoelectric ceramics, the moving rotor 7 can produce a linear displacement output along the forward or backward direction of the stator 6. Driven by an out-of-phase sawtooth wave waveform signal, the moving rotor 7 The rotor 7 can generate a rotational angular displacement output in the counterclockwise or clockwise direction around its axis of rotation. By repeating this process repeatedly, the piezoelectric actuator can realize linear-rotary two-degree-of-freedom motion.

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. Any modifications, equivalent replacements and improvements made within the spirit and principles of the present invention should be included in the protection of the present invention. within range.

Claims (8)

1. The piezoelectric drive-based integrated two-degree-of-freedom stepping actuator is characterized by comprising a stator (6), a sliding guide rail, a driving mechanism and a moving rotor (7);

the sliding guide rail comprises a guide rail A (5) and a guide rail B (11), the guide rail A (5) and the guide rail B (11) are symmetrically arranged on the lower surface of the flexible mechanism (8), the guide rail A (5), the guide rail B (11) and the lower surface of the flexible mechanism (8) form a guide rail sliding chute, and the stator (6) is assembled in the guide rail sliding chute;

actuating mechanism includes flexible mechanism (8), piezoceramics A (3) and piezoceramics B (9), flexible mechanism (8) are including moving rotor mount pad (14), board type flexible hinge (15), just circular type flexible hinge (16) and flexible installing frame (19), two pairs of board type flexible hinge (15) are installed to the one end inboard of flexible installing frame (19), and every is a piezoceramics mounting groove of board type flexible hinge (15) constitution, and two pairs of board type flexible hinge (15) link to each other with moving rotor mount pad (14) through a just circular type flexible hinge (16) respectively, move rotor (7) install in move on rotor mount pad (14).

2. The integrated two-degree-of-freedom stepping actuator based on piezoelectric driving as claimed in claim 1, wherein the two piezoelectric ceramic mounting grooves are symmetrically distributed about the central axis of the flexible mechanism (8) and are respectively located on two sides of the rotor mounting seat (14).

3. Integrated two-degree-of-freedom stepping actuator based on piezoelectric actuation according to claim 2, wherein the flexible mechanism (8) is integrally formed from a single piece of resilient metal material.

4. The integrated two-degree-of-freedom stepping actuator based on piezoelectric driving as claimed in any one of claims 1 to 3, wherein the moving rotor (7) is a part with a rotating shaft, the moving rotor (7) is mounted on the moving rotor mounting seat (14) through the rotating shaft, and the rotating shaft of the moving rotor (7) is in transition fit with the central hole of the moving rotor mounting seat (14).

5. The integrated two-degree-of-freedom stepping actuator based on piezoelectric driving as claimed in claim 4, wherein a rotating shaft of the moving rotor (7) penetrates through the gasket (18), the central hole of the moving rotor mounting seat (14), the gasket (18), the elastic ring (17) and the other gasket (18) in sequence and then is matched and locked with the nut.

6. The integrated two-degree-of-freedom stepping actuator based on piezoelectric driving as claimed in claim 4, wherein the outer side surfaces of the guide rail A (5) and the guide rail B (11) are respectively provided with an adjusting bolt.

7. The integrated two-degree-of-freedom stepping actuator based on piezoelectric driving as claimed in claim 4, wherein the driving mechanism further comprises a pre-tightening gasket A (2), a pre-tightening bolt A (1), a pre-tightening gasket B (10) and a pre-tightening bolt B (12), the pre-tightening gasket A (2) and the pre-tightening bolt A (1) are used for adjusting the pre-tightening force of the piezoelectric ceramic A (3), and the pre-tightening gasket B (10) and the pre-tightening bolt B (12) are used for adjusting the pre-tightening force of the piezoelectric ceramic B (9).

8. The integrated two-degree-of-freedom stepping actuator based on piezoelectric driving as claimed in claim 3, wherein the elastic metal material is 65Mn spring steel which is subjected to quenching treatment.

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