CN103199732A - Micropositioner based on piezoelectric thread driving technology - Google Patents

Abstract

The invention discloses a micro-motion stage based on piezoelectric thread drive technology, which belongs to the field of precision machinery and automatic control. The micro-motion stage based on piezoelectric thread drive technology includes a one-dimensional Micro-motion stage and two-dimensional micro-motion stage. Two fixed sleeves are arranged symmetrically on appropriate positions on the upper plate, and the two piezoelectric thread drivers are connected with the internal threads of the fixed sleeves; the center of the piezoelectric thread driver fixes the driving screw and contacts the lower plate; the two springs are connected with the lower plate. The steel ball is supported in an isosceles triangle between the upper plate and the lower plate. The micro-vibration of the piezoelectric ceramics of the present invention can make the driving screw move in the forward and reverse directions along the straight line, and the driving screw directly drives the micro-motion table without an intermediate transmission mechanism; The moving stage can realize XY rotation and tilting the table. This new type of micro-moving stage has the characteristics of simple structure, high integration, and strong load capacity. It is suitable for applications in the fields of optical path adjustment, precision drive, microsystem, structural attitude control, and biomedicine.

Description

Micro-motion stage based on piezoelectric screw drive technology

technical field

The invention belongs to the field of precision machinery and automatic control, and in particular relates to a micro-motion stage based on piezoelectric screw drive technology, which is especially suitable for applications in the fields of optical path adjustment, precision drive, microsystem, structural attitude control, and biomedicine.

Background technique

Traditional micro-control consoles usually use manual fine-tuning knobs, so the accuracy and repeatability are poor. For the micro-table control system with multi-dimensional motion, manual adjustment is more complicated and the precision is lower. The traditional electromagnetic motor equipped with a reducer can also be finely adjusted, but this type of system is usually large in size, complex in system, and high in equipment cost, and its reduction device is composed of multiple gears, resulting in a large empty motion of the reduction transmission mechanism and inconvenient use . In the 1990s, the "tablecloth principle" piezoelectric actuator invented by the American NewFocus Company was driven by a piezoelectric actuator. It is characterized by small size, high displacement resolution, and convenient operation. However, the cost of the micro-motion stage is very high, and the selling price is expensive.

In recent years, due to the rapid development of nanotechnology, piezoelectric transducers (PZT) have been widely used as drivers in precision positioning systems. In order to meet the requirements of the traditional micro-displacement mechanism, a large and complex positioning system must be designed. However, micro-displacement devices that usually use piezoelectric drivers have a simple structure and high positioning accuracy. This type of micro-displacement device is also a research hotspot in recent years, and it can theoretically achieve a large range and extremely high displacement resolution. In addition, micro-displacement devices based on piezoelectric drive technology are conducive to meeting the actual use requirements of highly integrated electromechanical systems in the future.

The micro-motion stage device designed based on the piezoelectric actuator has many advantages, but usually the stroke of this type of micro-motion stage is short and has many restrictions. Therefore, in recent years, there have been continuous improvements to the driver, enabling it to work on a micro-motion stage with a large stroke, and to maintain a high displacement resolution.

At present, most micro-motion stages use rotating electromagnetic motors or piezoelectric motors, and use an external screw nut motion conversion mechanism at the output shaft of the motor or motor to indirectly convert rotational motion into linear motion, and then drive the micro-motion stage. The table top of the moving stage produces micro-displacement. The two-dimensional micro-motion stage driven by piezoelectric ultrasonic micro-motor proposed by Dong Shuxiang, Li Longtu and others in 1998 is a typical type of this type. As shown in Figures 1 and 2), this micro-motion table has high precision, flexible structure, and can realize XY table rotation. However, since the transmission mechanism adopts the motion conversion mode of the screw nut hanging on the output shaft of the motor, an idle stroke is bound to be generated during the driving process, which is inevitable from the structural driving principle, thereby reducing the The stability and positioning accuracy are further improved; and the structural design of this type of micro-motion table is not simple enough, especially the structure of the motor itself is complex, there are many parts, it is inconvenient to assemble and adjust, and it will be more difficult to integrate in the future; at the same time, the support , The structure of the threaded sleeve makes the precision of the micro-motion table greatly affected by boundary conditions such as installation and fixing methods (as shown in Figure 1), the levelness of the support and the upper plate of the micro-motion table, the output shaft of the piezoelectric motor and the The gap between the threaded sleeve and the like will affect the accuracy of the micro-motion table; in addition, the main problem of this structure is that the performance index of the micro-motion table is greatly affected by the piezoelectric ultrasonic micro-motor, and the gap between the micro-motor and the micro-motion table The fixing method and the size of the fixing force directly affect the output characteristics such as the vibration mode and output torque of the micro-motor itself, which indirectly affects the positioning accuracy, repeat positioning accuracy, stability and reliability of the micro-motion stage.

Contents of the invention

The purpose of the present invention is to overcome the deficiencies of the prior art, and propose a micro-motion table based on piezoelectric thread drive technology, which is characterized in that the micro-motion stage based on piezoelectric thread drive technology includes a piezoelectric thread driver to directly drive the micro One-dimensional micro-motion stage and two-dimensional micro-motion stage; the one-dimensional micro-motion stage is at both ends of a cross center line of the relatively movable upper plate 3 and lower plate 4, and the spring 7 is supported on the upper plate 3 and the lower plate 4, then the screw 6 passes through the spring 7 to connect the upper plate 3 and the lower plate 4, and at the other end of the cross center line, the steel ball 5 is fixed between the upper plate 3 and the lower plate 4 Between them, the fixed sleeve 2 is inserted into the round through hole on the upper plate 3 at the other end, and the stator circular plate 10 of the piezoelectric thread driver 1 is connected with the internal thread of the fixed sleeve 2; the center of the piezoelectric thread driver 1 fixes the drive screw 8 , and is in contact with the lower plate 4 to form a one-dimensional micro-motion stage. When the lower plate 4 of the micro-motion stage is fixed, the piezoelectric thread driver 1 drives the drive screw 8 to make a linear motion, directly driving the upper plate 3 and the load fixed on it. device movement;

The two-dimensional micro-motion table is symmetrically provided with round through holes at both ends of one of the diagonals of the upper plate 3, each of the two round through holes is fitted with a fixed sleeve 2, and two piezoelectric thread drivers 1 The stator circular plate 10 is connected with the internal thread of the fixed sleeve 2; the piezoelectric thread driver 1 fixes the driving screw 8 in the center and contacts the lower plate 4; at one end of the other diagonal line, the steel ball 5 is fixed on the upper plate 3 and Between the lower boards 4, on the same side of the other diagonal line as the steel ball 5, where the steel ball 5 forms an isosceles triangle, the spring 7 is supported between the upper board 3 and the lower board 4, and then the screw 6 passes through the spring After 7, the upper plate 3 and the lower plate 4 are connected to form a two-dimensional micro-motion table. When the lower plate 4 of the micro-motion table is fixed, the piezoelectric thread driver 1 drives the drive screw 8 to make a linear motion, directly driving the upper plate 3 and the fixed plate. The load device on it moves.

Both the center of the upper plate 3 and the lower plate 4 have a central through hole; they are micro-movement platens.

One of the screw holes on the upper plate 3 and the lower plate 4 is a through hole, and the other is a threaded hole matched with the screw 6 .

The piezoelectric screw driver includes an excitation element group, a driving screw and a coaxial stator; the stator is composed of a circular plate 10 and a circular tube 11, and the circular tube 11 is fixed and perpendicular to the center of the circular plate 10; the excitation element group consists of four Piezoelectric ceramic sheets 12 and electrode sheets 13 are alternately arranged and sleeved on the outer circle of the round tube, and are threaded in the middle of the outer circle of the round tube 11 through a lock nut 14, and the inner thread 111 in the lower part of the round tube is connected with the driving screw 8, and the circle The outer edge of the plate 10 has an external thread 110 for connecting with the fixed sleeve 2, the fixed sleeve 2 is connected with the piezoelectric screw driver 1 through the internal thread, and the wire passes through the rectangular through hole 15 on the fixed sleeve 2 to connect with the The electrode sheet 13 is connected, when the electric signal is applied, the piezoelectric screw driver 1 on the fixed sleeve 2 pushes the driving screw 8 to make a linear motion under the action of the excitation element group; the driving screw directly drives the micro-motion table, without The intermediate transmission mechanism has no mechanical clearance.

The piezoelectric screw driver realizes the direct conversion of the micro-vibration of the piezoelectric ceramic group into the positive direction of the driving screw along the straight line by setting the polarization directions of different partitions of the piezoelectric ceramics and the waveforms of the driving voltage applied to different partitions. or in the opposite direction.

The output shaft of the piezoelectric screw driver is a driving screw without an intermediate transmission mechanism, which can directly drive the relative movement between the upper plate and the lower plate of the micro-motion stage.

The beneficial effect of the present invention is that the output shaft of the piezoelectric thread driver replaces the traditional lead screw structure in the micro-motion platen of the present invention, and there is no transmission mechanism as a whole, and the micro-motion platen is directly driven by the output shaft of the piezoelectric thread driver, which is a kind of Small volume, high-resolution piezoelectric thread driver with independent structure, the driver is simple in structure, easy to install, and easy to assemble with the micro-motion table, compared with the traditional micro-motion table using electromagnetic motor or ultrasonic motor as the driving element , its reliability and resolution are greatly improved, and it is more suitable for harsh working environments. Has the following characteristics:

1. The micro-vibration of piezoelectric ceramics is directly coupled into a macroscopic mechanical thread motion to realize the one-dimensional or two-dimensional precise nanoscale positioning motion of the micro-motion stage. This conversion from micro-vibration to mechanical thread motion is not a traditional one. Conversion from screw nut type rotary to linear motion. The present invention can directly convert the micro-vibration of the above-mentioned piezoelectric ceramics into the linear drive of the screw mechanism by regulating the electric polarization direction of different partitions of the piezoelectric ceramics and the specific waveform of the driving voltage applied to the different partitions, that is, the driving force The micro-vibration directly comes from piezoelectric ceramics, and does not require the conversion of the movement mode of the traditional nut-screw mechanical mechanism, so there is no problem of mechanical clearance. Moreover, this new type of piezoelectric driving method has a simple structure, and the micro-vibration of piezoelectric ceramics and the screw transmission mechanism form an independent system or device, which realizes the high integration of the micro-motion table driving system.

2. The micro-motion table can be rotated in XY, and the table can be tilted, which is not a traditional linear micro-motion table. The fixed sleeve is used to match the center hole of the upper plate of the micro-motion stage, and the fixed sleeve is installed on the upper plate of the micro-motion stage with fastening screws. The device is compact and the fixing method is simple, so that the driving screw of the piezoelectric thread driver directly drives the micro-motion stage. plate, two piezoelectric threaded drivers can independently realize the pitch of the table, and then realize multi-dimensional rotation.

3. The advantage of integration is reflected in the number and cost of the components of the micro-motion table driving mechanical system. The micro-motion table is driven by a traditional piezoelectric motor (or ultrasonic motor), and the rotational motion of the ultrasonic motor is converted through the screw nut The mechanism forms the linear micro-motion of the micro-motion stage, and the number of main components involved in the one-dimensional stage is at least 12. However, in the novel drive mode of the present invention, only six parts are needed to realize the same functional one-dimensional table. If it is a two-dimensional table, the number of parts is doubled according to the number of dimensions. The more dimensions, the more obvious the cost advantage and technical advantage of the technology.

Description of drawings

Figure 1 is a schematic diagram of the structure of a traditional piezoelectric motor.

FIG. 2 is a schematic diagram of the driving principle of the micro-motion stage in FIG. 1 .

Fig. 3 is a schematic diagram of the driving principle of the micro-motion table based on the piezoelectric thread driving technology.

Fig. 4 is a schematic structural diagram of a one-dimensional micro-motion stage directly driven by a piezoelectric thread driver.

FIG. 5 is a schematic side view of FIG. 4 .

FIG. 6 is a schematic diagram of the micro-motion of the micro-motion platen in FIG. 4 .

Fig. 7 is a schematic structural diagram of a two-dimensional micro-motion stage directly driven by a piezoelectric thread driver.

Fig. 8 is a structural schematic diagram of a piezoelectric thread driver.

Fig. 9 is a schematic diagram of the partitioning, polarization and power-on modes of the piezoelectric thread driver ceramic sheet.

Detailed ways

The present invention provides a micro-motion stage based on piezoelectric thread drive technology, which includes a one-dimensional micro-motion stage and a two-dimensional micro-motion stage directly driven by a piezoelectric thread driver. The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments.

In the structural diagram of the one-dimensional micro-motion table directly driven by the piezoelectric thread driver shown in Figure 4-6,

The one-dimensional micro-motion stage is at two ends of a cross center line of the upper plate 3 and the lower plate 4 that can move relatively, the spring 7 is supported between the upper plate 3 and the lower plate 4, and then the screw 6 passes through the spring After 7, connect the upper plate 3 and the lower plate 4, at one end of the other side of the cross center line, the steel ball 5 is fixed between the upper plate 3 and the lower plate 4, and in the round through hole on the upper plate 3 at the other end Cooperate with the insertion of the fixed sleeve 2, the stator plate 10 of the piezoelectric thread driver 1 is connected with the internal thread of the fixed sleeve 2; the center of the piezoelectric thread driver fixes the drive screw 8, and the drive screw 8 contacts the lower plate 4 to form a one-dimensional micro-motion tower,

In the structural diagram of the two-dimensional micro-motion table directly driven by the piezoelectric thread driver shown in Figure 7, on the diagonal line of the upper plate 3, round through holes are symmetrically arranged at both ends of one of them, and each of the two round through holes Cooperate with the fixed sleeve 2, the stator discs 10 of the two piezoelectric thread drivers 1 are respectively connected to the internal threads of the fixed sleeve 2, and the center of the piezoelectric thread driver 1 fixes the drive screw 8 and contacts the lower plate 4; At one end of the other diagonal line, the steel ball 5 is fixed between the upper plate 3 and the lower plate 4, on the same side of the other diagonal line as the steel ball 5, and at the place where the steel ball 5 forms an isosceles triangle, the spring 7 supports Between the upper plate 3 and the lower plate 4, then the screw 6 passes through the spring 7 to connect the upper plate 3 and the lower plate 4 to form a two-dimensional micro-motion table;

The above-mentioned upper plate 3 and lower plate 4 are micro-motion platens that can move relatively. When the lower plate 4 is fixed, the plate is a fixed plate, and the upper plate 3 is a relatively movable plate, and vice versa; steel balls 5, Two sets of tension springs 7 set on the screws 6 are used to keep the upper plate 3 and the lower plate 4 in a proper pre-tightening state. The two sets of springs and steel balls form the three stress points of the upper plate 3 and the lower plate 4 ; When the lower plate 4 of the micro-motion table is fixed, the piezoelectric thread driver 1 drives the drive screw 8 to do linear motion, directly drives the upper plate 3 and the load device fixed thereon to move; Schematic diagram of the driving principle of the micro-motion stage.

Fig. 8 is a structural schematic diagram of a piezoelectric thread driver, the piezoelectric thread driver includes an excitation element group, a drive screw and a coaxial stator; the stator is composed of a circular plate 10 and a circular tube 11, and the circular tube 11 is fixed and perpendicular to the circle The center of the plate 10; the excitation element group is composed of four piezoelectric ceramic sheets 12 and electrode sheets 13 arranged alternately on the outer circle of the round tube, and is threaded with the middle part of the outer circle of the round tube 11 through the lock nut 14, and the lower part of the round tube The internal thread 111 is connected with the driving screw 8, and the outer edge of the circular plate 10 has an external thread 110 for connecting with the fixed sleeve 2. The fixed sleeve 2 is connected with the piezoelectric screw driver 1 through the internal thread, and the wire passes through the fixed sleeve. The rectangular through hole 15 on the 2 is connected with the electrode sheet 13, when the electric signal is applied, the piezoelectric screw driver 1 on the fixed sleeve 2 pushes the drive screw 8 to do linear motion under the action of the excitation element group; The driving screw directly drives the micro-motion stage, without intermediate transmission mechanism, and without mechanical clearance.

Fig. 9 is a schematic diagram of the partitioning, polarization and power-on modes of the piezoelectric thread driver ceramic sheet. The excitation element group in Figure 8 is divided into two groups of piezoelectric ceramics 121 and piezoelectric ceramics 122 during excitation, and the surface electrodes of each piece of ceramics are evenly divided into two partitions, and each partition is polarized along the thickness direction of the ceramics, but the poles The direction of polarization is opposite, and the symbols "+" and "-" in the figure represent different polarization directions. When placing the first group of piezoelectric ceramics 121 and the second group of piezoelectric ceramics 122, the space is staggered by 90 degrees, and the phase difference is added to the first group of piezoelectric ceramics 121 and the second group of piezoelectric ceramics 122. The sine signal and cosine signal are 90 degrees, when the two-phase AC signal with a phase difference of 90 degrees is loaded on the first group of piezoelectric ceramics 121 and the second group of piezoelectric ceramics 122 through the electrode sheet 13, the stator will be excited to act Rotary shaking head bending vibration, the traveling wave fluctuation will cause the surface particles of the stator to produce elliptical motion, and this elliptical motion contacts the drive screw 8 through the drive thread 111 on the stator, so that the drive screw 8 rotates in the circumferential direction and produces linear motion, exchanging two The signal can realize the reverse rotation and reverse linear motion of the driving screw 8.

In the above-mentioned embodiments, in addition to piezoelectric ceramic materials, magnetostrictive materials, electrostrictive materials, artificial muscles, shape memory alloys, etc. can also be used for the excitation element.

Claims (6)

1. the micropositioner based on the piezoelectricity thread Driving technique is characterized in that, described micropositioner based on the piezoelectricity thread Driving technique comprises that the employing piezoelectricity thread driver directly drives micropositioner one dimension micropositioner and prototype with displacement resolution; Described one dimension micropositioner is two ends at the right-angled intersection center line of relatively-movable upper plate (3) and lower plate (4), spring (7) is supported between upper plate (3) and the lower plate (4), screw (6) is connected upper plate (3) after passing spring (7) with lower plate (4) then, another a end at the right-angled intersection center line, steel ball (5) is fixed between upper plate (3) and the lower plate (4), cooperate in the round tube hole on the upper plate (3) of the other end and insert fixed muffle (2), the stator plectane (10) of piezoelectricity thread driver (1) is connected with fixed muffle (2) internal thread; Piezoelectricity thread driver (1) center fixation drive screw (8), and contact with lower plate (4), constitute the one dimension micropositioner, when the lower plate (4) of micropositioner fixedly the time, piezoelectricity thread driver (1) drives drive screw (8) and does rectilinear motion, the load device motion that directly drives upper plate (3) and be fixed thereon;

Described prototype with displacement resolution is on upper plate (3) diagonal, be symmetrical arranged round tube hole on one the end positions therein, each cooperates insertion fixed muffle (2) in two round tube holes, and the stator plectane (10) of two piezoelectricity thread drivers (1) is connected with fixed muffle (2) internal thread; Piezoelectricity thread driver (1) center fixation drive screw (8), and contact with lower plate (4); At another cornerwise end, steel ball (5) is fixed between upper plate (3) and the lower plate (4), in this another diagonal and steel ball (5) the same side, be the isosceles triangle place with steel ball (5), spring (7) is supported between upper plate (3) and the lower plate (4), screw (6) passes behind the spring (7) that (3 are connected with lower plate (4) with upper plate then, constitute prototype with displacement resolution, when the lower plate (4) of micropositioner fixedly the time, piezoelectricity thread driver (1) drives drive screw (8) and does rectilinear motion, the load device motion that directly drives upper plate (3) and be fixed thereon.

2. according to the described micropositioner based on the piezoelectricity thread Driving technique of claim 1, it is characterized in that central through hole is all opened at the center of described upper plate (3) and lower plate (4); Fine motion platen each other.

3. according to the described micropositioner based on the piezoelectricity thread Driving technique of claim 1, it is characterized in that, the screw hole on described upper plate (3) and the lower plate (4), one is through hole, another is the screwed hole that cooperates with screw (6).

4. according to the described micropositioner based on the piezoelectricity thread Driving technique of claim 1, it is characterized in that described piezoelectricity thread driver comprises the coaxial composition of exciting element group, drive screw and stator; Stator is made up of plectane (10) and pipe (11) two parts, and pipe (11) is fixing and perpendicular to the center of plectane (10); The exciting element group is alternately arranged to be enclosed within on the pipe cylindrical with electrode slice (13) by four piezoelectric ceramic pieces (12) and is formed, and be threaded by locking nut (14) and pipe (11) cylindrical middle part, (8 are connected pipe lower internal thread (111) with drive screw, the outer ledge of plectane (10) is useful on the external screw thread (110) that is connected with fixed muffle (2), fixed muffle (2) is connected by internal thread and piezoelectricity thread driver (1), the rectangular through-hole (15) that lead passes on the fixed muffle (2) is connected with described electrode slice (13), after applying the signal of telecommunication, the piezoelectricity thread driver (1) on the fixed muffle (2) promotes drive screw (8) and does rectilinear motion under the effect of exciting element group; Described drive screw directly drives micropositioner, and no intermediate transmission mechanism does not have the existence of mechanical play.

5. according to the described micropositioner based on the piezoelectricity thread Driving technique of claim 1, it is characterized in that, the polarised direction of described piezoelectricity thread driver by the different subregions of self piezoelectric ceramic are set and different section posts add the waveform of driving voltage, realize that little vibration with described piezoelectric ceramic group is directly changed into drive screw along the forward of straight line or moves in the other direction.

6. according to the described micropositioner based on the piezoelectricity thread Driving technique of claim 1, it is characterized in that, described piezoelectricity thread driver output shaft is drive screw, and no intermediate transmission mechanism can directly drive the upper plate of the described micropositioner of realization and the relative motion between the lower plate.

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