CN104742099A - Self-propelled planar three-degrees-of-freedom piezoelectric driving platform - Google Patents

Abstract

The invention discloses a self-propelled planar three-degree-of-freedom piezoelectric driving platform, which comprises a driving element, a dynamic platform and a static platform. The driving element includes 4 linear motion piezoelectric drivers, and each driver is provided with a through hole in its symmetrical center; the moving platform is a square plate with a threaded hole in the center of the side, and 4 connecting bolts are connected through the threaded hole. The four linear motion piezoelectric drivers are respectively connected to the four sides of the moving platform; the static platform is determined according to the performance parameters of the drivers and serves as the working plane of the drivers. Applying a specific excitation signal to the linear motion piezoelectric driver can realize bidirectional linear motion; by combining the linear motion of 4 piezoelectric stack drivers, the two-degree-of-freedom linear motion of the platform in the plane and the rotational motion around the axis can be realized. The planar three-degree-of-freedom drive platform constructed by the invention has the advantages of simple structure, high precision, large stroke and high load.

Description

A self-propelled planar three-degree-of-freedom piezoelectric drive platform

technical field

The invention relates to a drive positioning device, which belongs to the technical field of piezoelectric precision drive, in particular to a self-propelled plane three-degree-of-freedom piezoelectric drive platform.

Background technique

With the rapid development of precision engineering, the modern manufacturing field puts forward higher and higher requirements for the precision, speed and stroke of the precision motion platform, and its positioning accuracy and stroke range directly affect the precision and breadth of production and processing. The traditional motion platform is mainly driven by an electromagnetic rotating motor. This driving method has mature technology and stable performance, but inevitably there are many intermediate motion conversion links and elastic deformation, which makes the real-time performance of the platform poor and can be realized. The positioning accuracy or speed of the linear motion is low. In addition, because the motor itself is based on the working principle of electromagnetic effects, it will inevitably bring electromagnetic interference to the working environment. Piezoelectric actuators have obvious advantages in terms of positioning accuracy and response speed. Research on multi-degree-of-freedom positioning platforms based on piezoelectric actuators has become a hot topic in recent years. However, motion platforms based on different piezoelectric actuators are still There are many shortcomings: the resonant piezoelectric driver represented by the ultrasonic motor is very sensitive to the voltage frequency and the structural size of the stator, and it is difficult to ensure the consistency of platform performance and stability in mass production; the accuracy of the non-resonant piezoelectric driver such as the traditional inchworm type To a large extent, it depends on the machining accuracy of the guiding mechanism. In addition, the structural design of the driver is relatively complicated, and it is difficult to build a multi-degree-of-freedom motion platform; although the piezoelectric micro-displacement platform has the advantages of simple mechanism, good controllability, and high precision, but Its itinerary is generally Below, it is difficult to achieve a large stroke.

Contents of the invention

The technical problem to be solved by the present invention is to design a self-propelled planar three-degree-of-freedom piezoelectric drive platform to realize the positioning requirements of planar three-degree-of-freedom, large stroke and high precision in view of the defects and deficiencies of the aforementioned background technology.

The present invention adopts the following technical solutions for solving the problems of the technologies described above:

A self-propelled planar three-degree-of-freedom piezoelectric drive platform includes a drive element, a moving platform 8, and a static platform 7; the drive element includes several linear motion piezoelectric drivers 9, and the linear motion piezoelectric drivers 9 are placed on the static platform 7 above, and the linear motion piezoelectric actuators 9 are arranged symmetrically in pairs; the moving platform 8 is fixedly connected to the middle position of the linear motion piezoelectric actuators 9, and the static platform 7 is formulated according to the performance parameters of the actuators as the linear motion piezoelectric actuators 9 working plane.

Each linear motion piezoelectric driver 9 is provided with a through hole at its center. The moving platform 8 is a flat plate with a side and a threaded hole in the center of the side. The linear motion piezoelectric driver 9 is connected to the moving platform by connecting bolts 10. 8 sides.

The driving element includes four linear motion piezoelectric drivers 9, and the moving platform 8 is a rectangular flat plate with sides, and each side is correspondingly provided with a linear motion piezoelectric driver 9, and the linear motion piezoelectric drivers 9 are symmetrical in pairs .

The linear motion piezoelectric driver 9 includes an elastic element 1, a guide rod 2, a piezoelectric stack 5, a pre-tightening wedge, and a pre-tightening bolt 6;

The elastic element 1 includes a horizontal beam, which is connected to five tooth columns, wherein, two tooth columns are located on the upper side of the horizontal beam, and three tooth columns are located on the lower side of the horizontal beam as the linear motion piezoelectric actuator 9 The moving feet of the act on the static platform 7;

Every two tooth columns and the horizontal beam form an empty slot, in which a piezoelectric stack 5, a pre-tightening device and a guide rod 2 are arranged; the piezoelectric stack 5 is arranged between two groups of pre-tightening devices;

The pre-tightening device includes two sets of pre-tightening wedges arranged opposite to each other, each set of pre-tightening wedges includes an upper wedge and a lower wedge connected by a pre-tightening bolt 6, through which the pre-tightening bolt 6 adjusts the pressure applied to the piezoelectric The pre-tightening force on the stack 5; the two sets of pre-tightening wedges are provided with rectangular grooves on the opposite surfaces, which are used to clamp the piezoelectric stack 5, and the upper and lower wedges are matched by an inclined plane;

There is a groove at the corresponding position of the contact surface of the pre-tensioning device and the elastic element 1, and the guide rod 2 is assembled in the groove, and the angle of the contact surface is automatically adjusted during the pre-tightening, so as to avoid the contact between the two during the driving process. If the planes are not parallel, a shear force will be generated to destroy the piezoelectric stack 5 .

Compared with the prior art, the present invention adopts the above technical scheme and has the following technical effects:

The present invention has the following characteristics: the driving element of the present invention is a new type of bionic piezoelectric driver, which uses the non-resonant vibration mode excited by the piezoelectric stack to generate the orderly motion of the moving feet of the elastic element to realize the bidirectional linear motion of the driver. Movement, abandoning the clamping mechanism and guiding mechanism of the traditional inchworm piezoelectric driver, which can not only maintain the advantages of the non-resonant piezoelectric driver, but also eliminate the defects caused by the clamping mechanism and guiding mechanism of the traditional inchworm piezoelectric driver , so that the planar three-degree-of-freedom drive platform of the present invention has the advantages of simple structure, high precision, large stroke, high load, etc., and can realize the positioning target of three-degree-of-freedom large stroke and high precision.

An orderly excitation signal is applied to the piezoelectric stack in the linear motion piezoelectric driver, so that the three moving feet of the elastic element can produce an orderly motion similar to that of a caterpillar walking, thereby realizing the bidirectional linear motion of the driver on the static platform; through the combination of The two-degree-of-freedom linear motion of the platform can be realized by the synchronous linear motion of the two piezoelectric actuators on the same side; the rotary motion of the platform around the axis in the plane can be realized by combining the synchronous and opposite linear motion of the two piezoelectric actuators on the opposite side. ; The direction of synchronous linear motion of the four piezoelectric drivers constitutes counterclockwise or clockwise, which can realize the rotary motion of the platform around the axis in the plane.

Description of drawings

Fig. 1 is a structural schematic diagram of a planar three-degree-of-freedom piezoelectric drive platform of the present invention;

Fig. 2 is a schematic structural view of the linear motion piezoelectric driver of the present invention;

Fig. 3 is a schematic structural view of the elastic element of the present invention;

Fig. 4 is a schematic diagram of the connection between the pre-tightening wedge and the pre-tightening bolt of the present invention;

Fig. 5 is the principle diagram of the preload of the preload wedge of the present invention;

Fig. 6 is a stepping principle diagram of the linear motion piezoelectric driver of the present invention;

Fig. 7 is a signal diagram of the linear motion piezoelectric driver of the present invention;

Fig. 8 is a schematic diagram of the translational movement of the planar three-degree-of-freedom piezoelectric drive platform of the present invention;

Fig. 9 is a working schematic diagram of the planar three-degree-of-freedom piezoelectric drive platform of the present invention to realize the rotary motion;

Among them: 1-elastic element, 2-guide rod, 3-lower wedge, 4-upper wedge, 5-piezoelectric stack, 6-preload bolt, 7-static platform, 8-moving platform, 9-line Motion piezoelectric actuator, 10-coupling bolt.

Detailed ways

The present invention provides a self-propelled planar three-degree-of-freedom piezoelectric drive platform. In order to make the object, technical solution and effect of the present invention clearer and clearer, the present invention will be further described in detail with reference to the accompanying drawings and examples. It should be understood that the specific implementations described here are only used to explain the present invention, not to limit the present invention.

Below in conjunction with accompanying drawing, the technical scheme of invention is described in detail:

As shown in FIG. 1 , a self-propelled planar three-degree-of-freedom piezoelectric driving platform of the present invention includes a driving element, a dynamic platform and a static platform. It is characterized in that: the driving element includes 4 linear motion piezoelectric drivers, and each linear motion piezoelectric driver is provided with a through hole in its symmetrical center; the moving platform is a square plate with threaded holes in the center of four sides, Four bolts are fitted through holes to connect and install four linear motion piezoelectric drivers on the four sides of the moving platform; the static platform is determined according to the performance parameters of the drivers and serves as the working plane of the drivers.

As shown in Figure 2-5, the linear motion piezoelectric actuator includes an elastic element, a guide rod, a piezoelectric stack, a pre-tightening wedge, and a pre-tightening bolt; the elastic element has five tooth columns and a horizontal beam , each of the three empty slots formed by the five tooth columns is provided with a piezoelectric stack, a pre-tensioning device and a guide rod, and the tooth column below the horizontal beam acts on the static platform as a moving foot; the piezoelectric stack is arranged on two Between the group of pre-tightening wedges, the pre-tightening force applied to the piezoelectric stack is adjusted through the pre-tightening bolts; the pre-tightening wedges are matched by an upper wedge with a threaded hole and a lower wedge with a groove through a slope Composition; the pre-tightening wedge is composed of an upper wedge with a threaded hole and a lower wedge with a groove through an inclined plane, and the pre-tightening bolt is connected to the upper wedge and the lower wedge for cooperation. The relative position of the pre-tightening wedge is adjusted to provide the pre-pressure required by the piezoelectric stack; the guide rod is assembled between the pre-tightening device and the groove of the elastic element, which can automatically adjust the angle of the contact surface during pre-tightening to avoid During the driving process, the piezoelectric stack is destroyed by shearing force due to the non-parallel of the two contact surfaces.

As shown in Fig. 6 and Fig. 7, it is a feasible signal diagram and a stepping principle diagram of the linear motion piezoelectric driver of the present invention. The present invention aims to design a linear motion piezoelectric actuator in imitation of the characteristics of caterpillar movement. Generally, caterpillars have many pairs of legs, but their movements are similar: there is always a pair of legs that are used as moving feet to move vertically and horizontally. , while the other foot is always in contact with the ground as a supporting foot, and by virtue of the static friction with the ground, it will not slip during the movement, so the return phenomenon occurs. The present invention is designed based on these motion characteristics of the caterpillar, and according to the step motion characteristics of the driver in one cycle, the excitation signals of three piezoelectric stacks are designed. As shown in Figure 6, a signal cycle T is divided into 5t, corresponding to five working processes of the driver in one cycle, and each period of time t corresponds to a working process of the driver. Now, the stepping principle of the present invention will be described by using only one stepping motion cycle of the driver in conjunction with FIG. 6 . A complete step motion cycle is as follows: In the first t, the piezoelectric stack on the right side is excited to be in an elongated state, and the rest of the piezoelectric stacks are in a non-working state, so that the right side of the elastic element is driven to move vertically. Upward and horizontal movement to the right; in the second t, keep the stretched state of the right piezoelectric stack unchanged, excite the middle piezoelectric stack to be in an extended state, and the left piezoelectric stack to be in a non-working state, In this way, the middle moving foot of the elastic element is driven to move vertically upward, and at the same time, the right moving foot of the elastic element is moved vertically downward through the action of gravity; in the third t, the middle piezoelectric stack is kept in an elongated state. change, the piezoelectric stack on the left is excited to elongate while the piezoelectric stack on the right is shortened to the non-working state, thereby driving the middle of the elastic element to move horizontally to the right; in the fourth t, keep the left The elongation state of the piezoelectric stack remains unchanged, unloading the excitation signal of the middle piezoelectric stack makes the middle piezoelectric stack and the right piezoelectric stack in a non-working state, thereby driving the middle of the elastic element to move vertically downward , and at the same time make the elastic element move laterally and vertically upward through the action of gravity; in the fifth t, unload the excitation signal of the piezoelectric stack on the left side, so that all the piezoelectric stacks are in a non-working state, thereby driving The left side of the elastic element can move vertically downward and horizontally to the right. Based on the above working process, the three moving feet of the elastic element move horizontally to the right orderly from right to left, and this displacement is the step distance of the driver. In the same way, it can be obtained that by changing the timing relationship of exciting the three piezoelectric stacks, the three moving feet of the elastic element can move horizontally to the left in an orderly manner from left to right.

As shown in FIG. 8 , it is a schematic diagram of the working mode of the planar three-degree-of-freedom piezoelectric drive platform of the present invention to realize translational motion. The translational motion of the driving platform can be realized by combining the synchronous motion of the two linear motion piezoelectric drivers on the opposite side. With reference to Figure 8, only the combined motion of the two drivers parallel to the x-axis is illustrated: the two drivers are synchronous along the x The drive platform moves in the positive direction of the x-axis, and the whole drive platform makes a translational movement in the positive direction of the x-axis; the two drivers move synchronously in the negative direction of the x-axis, and the whole drive platform makes a translational movement in the negative direction of the x-axis. Similarly, the synchronous combined motion of the two drivers parallel to the y-axis can make the drive platform move in translation to the y-axis as a whole.

As shown in FIG. 9 , it is a schematic diagram of the working mode of the planar three-degree-of-freedom piezoelectric drive platform of the present invention to realize the rotary motion. The translational motion of the driving platform can be realized by combining the synchronous reverse motion of two linear motion piezoelectric actuators on opposite sides. Referring to Figure 9, it is only illustrated by the combined motion of the two actuators parallel to the x-axis: the two actuators are synchronous along the x axis If the two drivers move in the direction of the x-axis and the direction of movement of the two is clockwise, the whole drive platform will rotate clockwise around the z-axis in the xoy plane; if the two drivers move synchronously along the direction of the x-axis and the direction of movement of the two is counterclockwise, the overall drive platform will Rotate counterclockwise around the z-axis in the xoy plane. Similarly, the synchronous and reverse combined motion of the two drivers parallel to the y-axis can make the drive platform rotate around the z-axis as a whole. In addition, when the synchronous linear motion directions of the four piezoelectric actuators are configured counterclockwise or clockwise, the rotary motion of the platform around the z-axis in the plane can also be realized.

It can be understood that those skilled in the art can make equivalent replacements or changes according to the technical solutions and inventive concepts of the present invention, and all these changes or replacements should belong to the protection scope of the appended claims of the present invention.

Claims (4)

1. a self-propelled planar three freedom piezoelectric drive platform, is characterized in that: comprise driving element, moving platform (8) and silent flatform (7); Described driving element comprises several rectilinear motion piezoelectric actuators (9), and rectilinear motion piezoelectric actuator (9) is placed on silent flatform (7), and described rectilinear motion piezoelectric actuator (9) is symmetrical arranged in pairs; Described moving platform (8) is fixedly connected on the centre position of rectilinear motion piezoelectric actuator (9), and silent flatform (7) is formulated according to the performance parameter of driver, as the working face of rectilinear motion pressure driver (9).

2. a kind of self-propelled planar three freedom piezoelectric drive platform according to claim 1, it is characterized in that: each rectilinear motion piezoelectric actuator (9) is equipped with through hole at its center, described moving platform (8) is band side and center side is provided with the flat board of screwed hole, rectilinear motion piezoelectric actuator (9 sides being connected to moving platform (8) by connecting bolt (10).

3. a kind of self-propelled planar three freedom piezoelectric drive platform according to claim 2, it is characterized in that: described driving element comprises four rectilinear motion piezoelectric actuators (9), the flat board that described moving platform (8) is rectangular band side, on each side, correspondence is provided with a rectilinear motion piezoelectric actuator (9), and rectilinear motion piezoelectric actuator (9) is symmetrical between two.

4. any one self-propelled planar three freedom piezoelectric drive platform according to claims 1 to 3, is characterized in that: described rectilinear motion piezoelectric actuator (9) comprises flexible member (1), guide rod (2), piezoelectric stack (5), pretension voussoir, pretension bolt (6);

Described flexible member (1) comprises a horizontal beam, this horizontal beam connects five rooted tooth posts, wherein, have two rooted tooth posts to be positioned at the upside of horizontal beam, the motion foot that three rooted tooth posts are positioned at as this rectilinear motion piezoelectric actuator (9) on the downside of horizontal beam acts on silent flatform (7);

Every two rooted tooth posts and horizontal beam form a dead slot, arrange piezoelectric stack (5), pre-tightening apparatus and guide rod (2) in this dead slot; Described piezoelectric stack (5) is arranged between two groups of pre-tightening apparatus;

Described pre-tightening apparatus comprises two groups of pretension voussoirs arranged in opposite directions, often organizes pretension voussoir and comprises the upper voussoir and lower wedge block that are connected by pretension bolt (6), regulated the pretightning force be applied on piezoelectric stack (5) by described pretension bolt (6); The face that two groups of pretension voussoirs are relative is provided with rectangular channel, for clamping piezoelectric stack (5), is coordinated between upper and lower voussoir by inclined-plane;

Groove is had at the correspondence position of described pre-tightening apparatus and flexible member (1) contact surface, described guide rod (2) assembling in a groove, automatically adjust the angle of contact surface when pretension, avoid in driving process, produce shearing force because two contact surfaces are not parallel and destroy piezoelectric stack (5).