CN109818527A - Isosceles Trapezoid Stick-Slip Piezo Linear Actuator - Google Patents

Abstract

The invention discloses a kind of isosceles trapezoid stick-slip piezoelectric linear actuators, are made of pedestal, sliding block, isosceles trapezoid stator and pre-tightening mechanism.Sliding block and pre-tightening mechanism are installed on pedestal, are equipped with the pre-tightening mechanism of isosceles trapezoid stator for preloading isosceles trapezoid stator and sliding block.Isosceles trapezoid stator includes isosceles trapezoid compliant mechanism and four rectangular piezoelectric ceramic pieces, and isosceles trapezoid compliant mechanism is fixed on pre-tightening mechanism surface by two mounting holes.Sawtooth signal motivates piezoelectric ceramic piece, thus make isosceles trapezoid mechanism change driving foot and the x and y of shoe contact point to displacement, to change the frictional force of contact surface.Sawtooth signal rising edge, driving foot has biggish y to displacement, increase the normal pressure of slow polarizing stage, and then increase static friction driving force, sawtooth wave failing edge, driving foot have lesser y to displacement, reduce the kinetic frictional resistances in Quick-return stage, achieve the purpose that inhibit to retract, improves movenent performance.

Description

Isosceles trapezoid stick-slip piezoelectric linear actuator

Technical field

The present invention relates to a kind of precise driving device using intellectual material, especially a kind of piezoelectricity straight line driver.

Background technique

Piezoelectric actuator refers to by piezoelectric materials systems such as lead zirconate titanate (PZT), lead niobate zinc (PZN), lead magnesium niobates (PMN) At driver, micro-, nanometer or positioning application many of advantage, compare other executing agencies, it have high-resolution The distinguishing feature of (Subnano-class), high natural frequency (being greater than kHz) and high drive (being greater than thousand newton grades), but it is also deposited Displacement stroke small (10 μm -100 μm) the characteristics of, therefore the high-resolution of grade stroke is often realized in conjunction with stick-slip mechanism Rate movement.

The working principle of piezoelectricity stick-slip driving is as follows: under the excitation of asymmetric sawtooth voltage signal, utilizing piezoelectric vibrator Difference between kinematics and static friction power caused by asymmetry vibration generates micro-displacement to achieve the purpose that control driven object body. Specific implementation can be used asymmetric sawtooth wave and excited slowly with quick alternative excitation using inverse piezoelectric effect to piezo-electric stack Stator generate slowly with quick alternate motion deformation so that stator and mover are in " viscous " and " cunning " two kinds of motion states, Frictional force effect is lower to realize mechanical movement output.

However since piezoelectricity stick-slip drives slowly with the rapid deformation stage, the frictional force between stator and mover plays difference Effect, specially slowly the deformation driving stage is to show as friction drive, and show as rubbing when the rapid deformation driving stage Resistance.Given this, traditional piezoelectricity stick-slip driver, rollback phenomenon is obvious, and delivery efficiency is lower.

Summary of the invention

For realize big stroke, high-precision, heavy load combination precise driving device, while piezoelectricity stick-slip being inhibited to drive Rollback phenomenon, the invention discloses a kind of isosceles trapezoid stick-slip piezoelectric linear actuators.Itd is proposed piezoelectricity straight line driver etc. The trapezoidal stator of waist can act on the power of piezoelectric ceramics on slide block movement direction and stator positive pressure direction both direction simultaneously, produce Transverse movement is given birth to increase the normal pressure of the slow polarizing stage of piezoelectric ceramics, reduces the dynamic friction in piezoelectric ceramics Quick-return stage Power achievees the purpose that inhibit to retract.

The technical solution adopted by the present invention to solve the technical problems is:

A kind of isosceles trapezoid stick-slip piezoelectric linear actuator, mainly by pedestal (1), sliding block (2), isosceles trapezoid stator (3) It is formed with pre-tightening mechanism (4)；Sliding block (2) and pre-tightening mechanism (4) are installed on pedestal (1), and pre-tightening mechanism (4) is for preloading etc. The trapezoidal stator of waist (3) and sliding block (2)；The isosceles trapezoid stator (3) includes isosceles trapezoid compliant mechanism (3-1) and four squares Shape piezoelectric ceramic piece (3-2), isosceles trapezoid compliant mechanism (3-1) are fixed on pre-tightening mechanism (4) by two mounting holes (3-1-6) Surface；Isosceles trapezoid compliant mechanism (3-1) is flexible double rocker mechanism, and wherein horizontal axis (3-1-5) is fixed frame, drives sufficient institute Be connecting rod in bar, left flexible beam (3-1-3) and right flexible beam (3-1-4) be pasted with respectively left bending piezoelectric ceramics (3-2-1) and Right bending piezoelectric ceramics (3-2-2) is used as drive rocker；Four piezoelectric ceramic pieces (3-2) are believed by same positive-going sawtooth wave when work Number excitation, four piezoelectric ceramic pieces (3-2) generate polarization in the same direction, and left flexible beam (3-1-3) and right flexible beam (3-1-4) are by piezoelectricity The effect of potsherd (3-2) generates bending deformation, and the left imaginary motion profile for driving foot (3-1-1) and sliding block (2) contact point can Be decomposed into x to y to displacement, when driving foot is in close contact with sliding block, contact point imagination motion profile variation performance It drives foot (3-1-1) to be left and right drives contact surface normal normal pressure and tangential friction force between foot (3-1-2) and sliding block (2) Variation；In " viscous " stage, i.e. left driving foot (3-1-1) and when sliding block (2) contact movement, contact point imagination track be positive x to Negative y can generate larger normal pressure between left driving foot (3-1-1) and sliding block (2), therefore can generate more between the two to the synthesis of movement Big stiction drives the sliding block (2) along positive x to moving；In " cunning " stage, i.e., elasticity of the left flexible beam (3-1-3) because of itself When Quick-return, contact point imagination track is negative x to the synthesis with positive y to movement, at this time left driving foot (3-1-1) and sliding block (2) there is lesser normal pressure, the kinetic frictional resistances between the two can be smaller, and sliding block (2) is acted on the rollback generated by it also just between It is smaller.

Wherein, four piezoelectric ceramic pieces (3-2) are pasted in the way of polarization direction having the same, by same positive saw When tooth wave signal motivates, in the slow ascent stage of sawtooth signal, left flexible beam (3-1-3) and right flexible beam (3-1-4) are slow Bending deformation, right driving foot (3-1-2) separate with sliding block (2), mainly by static friction between left driving foot (3-1-1) and sliding block (2) Power effect, and because contact point has negative y to displacement, i.e., left flexible beam (3-1-3) and sliding block (2) are even closer, contact point positive pressure Power becomes larger, so static friction driving force is larger, has better load capacity；In the sawtooth signal rapid decrease stage, Zuo Rou Property beam (3-1-3) restore to the original state because of natural resiliency, left driving is mainly acted on by kinetic force of friction between (3-1-1) and sliding block (2) enough, this When contact point have positive y to displacement, to reduce the normal pressure of contact point, there is lesser kinetic frictional resistances, make sliding block (2) It retracts smaller；When four piezoelectric ceramic pieces (3-2) are motivated by same negative going sawtooth signal, sliding block (2) is by right driving foot (3- 1-2) effect will generate negative x to movement.

The invention has the advantages that driver overall structure is simple, convenient for output is adjusted, isosceles ladder is used Shape stator come generate transverse movement so that increase the slow polarizing stage of piezoelectric ceramics normal pressure, reduce piezoelectric ceramics Quick-return The kinetic force of friction in stage has achieved the purpose that inhibit to retract.

Detailed description of the invention

Present invention will be further explained below with reference to the attached drawings and examples.

Fig. 1 is isosceles trapezoid stick-slip piezoelectric linear actuator schematic diagram；

Fig. 2 is isosceles trapezoid stator schematic diagram；

Fig. 3 is isosceles trapezoid stator movement direction schematic diagram；

Fig. 4 is isosceles trapezoid stick-slip piezoelectric linear actuator working principle diagram；

Fig. 5 is inclination board-type flexibility mover isosceles trapezoid stick-slip piezoelectric linear actuator schematic diagram.

1. pedestal in figure, 2. sliding blocks, 3. isosceles trapezoid stators, 4. pre-tightening mechanisms

Specific embodiment

Implementation method is further illustrated with reference to the accompanying drawing:

[embodiment 1]

Isosceles trapezoid stick-slip piezoelectric linear actuator as shown in Figure 1, mainly by pedestal (1), sliding block (2), isosceles trapezoid Stator (3) and pre-tightening mechanism (4) composition.Sliding block (2) and pre-tightening mechanism (4) are installed on pedestal (1), and it is fixed to be equipped with isosceles trapezoid The pre-tightening mechanism (4) of sub (3) is for preloading isosceles trapezoid stator (3) and sliding block (2).It is sliding that cylindrical roller is had chosen in embodiment Block, impulse stroke are about 28mm, and the quality of sliding block is about 23.6g；Pre-tightening mechanism (4) is flat using manual displacement in embodiment Platform can achieve the purpose that preloading by adjusting and locking position of platform.Isosceles trapezoid stator (3) generates laterally after being powered Movement drives foot (3-1) that sliding block (2) is pushed to move horizontally according to stick-slip principle.Isosceles trapezoid stator (3) is the driving The core component of device, for providing driving force needed for slide block movement, as shown in Fig. 2, isosceles trapezoid stator (3) includes isosceles trapezoid Compliant mechanism (3-1) and four rectangular piezoelectric ceramic pieces (3-2), by two mounting holes (3-1-6) by isosceles trapezoid flexible machine Structure (3-1) is fixed on pre-tightening mechanism (4) surface.Two pieces of left side piezoelectric ceramic piece is known as left bending piezoelectric ceramics (3-2-1), passes through Epoxy resin is adhered to the arranged on left and right sides of left flexible beam (3-1-3), and other two potsherd is known as right bending piezoelectric ceramics (3-2-2) is adhered to the arranged on left and right sides of right flexible beam (3-1-4).Four piezoelectric ceramic pieces (3-2) are polarized along its thickness direction, And polarization direction having the same.Slide block movement direction is as shown in figure 3, left driving foot (3-1-1) is used to drive sliding block to x forward direction Mobile, right driving foot (3-1-2) is for driving sliding block mobile to x negative sense.There is an angle, θ between flexible beam and horizontal axis, passes through θ is adjusted the angle to adjust the x and y of driving foot to displacement.

Transverse movement refers to while generating the fortune of movement on x (slide block movement direction) and y (positive pressure direction) both direction It is dynamic.It is slow to increase piezoelectric ceramics that the isosceles trapezoid stator for the piezoelectricity straight line driver that this patent proposes can produce transverse movement The normal pressure of polarizing stage to increase the stiction in driving stage, while reducing the dynamic of piezoelectric ceramics Quick-return stage Frictional force achievees the purpose that inhibit to retract.

Specific working principle and contact point force analysis are as shown in Figure 4.

Under original state, as shown in fig. 4 a, preloaded force F₀Sliding block and two driving foots is kept to contact with each other, as time t=t₀ When, the preloaded force F of sliding block₀The normal pressure F generated equal to pre-load mechanism_P, it is left and right bending piezoelectric ceramics driving signal be Sawtooth wave.Each period of motion is divided into two steps:

Step 1: from moment t₀To t₁, left and right bending piezoelectric ceramics is slow simultaneously to be polarized, and isosceles trapezoid compliant mechanism is made Left driving foot obtains two displacement (l on the direction x and y_xAnd l_y), as shown in Figure 4 b, the stiction F of generation_SPush sliding block edge X-axis is just being marched forward Δ L；

Step 2: from moment t₁To t₂, left and right bending piezoelectric ceramics fast quick-recovery, therefore isosceles trapezoid compliant mechanism simultaneously Back to its initial position, due to the effect of inertia force, sliding block will remain in position as illustrated in fig. 4 c.By repeat step 1 and 2, the piezoelectric actuator proposed is done step-by-step to be moved along the big impulse stroke of x-axis forward direction.

From fig. 4, it can be seen that in t₀-t₁Stage, stiction F_SIt is the driving force that sliding block advances, it is left to drive the x generated enough Axis positive-displacement l_xFor pushing sliding block to move along x-axis forward direction；The y-axis negative sense of generation is displaced l_yFor increasing generation stiction F_SNormal pressure F_P.In step 2, by normal pressure F_PThe kinetic force of friction F of generation_dIt is resistance.Kinetic force of friction F_dIt may be defined as F_d= μ_d F_P；Wherein F_dIt is kinetic force of friction, μ_dIt is dynamic friction coefficient, F_PIt is normal pressure, normal pressure F_PIt is a variable.At the t1 moment, just Pressure F_PReach maximum value, from the t1 moment to the t2 moment, normal pressure F_PIt is rapidly decreased to F₀, can according to the definition of formula kinetic force of friction Know, normal pressure F_PReducing makes to generate the kinetic force of friction F to retract_dIt reduces, therefore inhibits rollback.It realizes along the big of x-axis negative sense When stroke motion, reversed sawtooth wave driving electric signal need to be only provided, the right driving of isosceles trapezoid stator drives sliding block along x enough Axis negative movement.

[embodiment 2]

The isosceles trapezoid stick-slip piezoelectric linear actuator can also improve and optimize to structure, as shown in figure 5, For the isosceles trapezoid stick-slip piezoelectric linear actuator for installing inclination board-type flexibility mover additional, flexible mover (2a) is mainly led by fixation Rail and flexible slide block composition, wherein critical component be flexible slide block by sliding block, shoe contact end, inclination straight beam type flexible hinge and Left and right driving foot contact jaw composition.The sliding block in guide rail and flexible slide block is wherein fixed using straight-line guide rail slide block, sliding block Contact jaw, inclination straight beam type flexible hinge and left and right driving foot contact jaw there is linear cutter to form, by epoxide-resin glue with Linear slider is pasted together.Whole driver mainly includes pedestal, flexible mover, isosceles trapezoid stator and pre-tightening mechanism.It is soft Property mover and pre-tightening mechanism be installed on pedestal, isosceles trapezoid stator is fixed on pre-tightening mechanism, pass through pre-tightening mechanism adjust etc. Latching force between the trapezoidal stator of waist and flexible mover.By the flexibility mover while inhibiting to retract by y to (positive pressure direction) Preload displacement be also translated into displacement of the x for pushing mover mobile to (the mover direction of motion), improve the output performance of driver.

Each technical characteristic of embodiment described above can be combined arbitrarily, for simplicity of description, not to above-mentioned reality The all possible combination of each technical characteristic in example is applied all to be described, however, as long as the combination of these technical characteristics is not deposited In contradiction, all should be considered as described in this specification.

The embodiments described above only express several embodiments of the present invention, and the description thereof is more specific and detailed, but simultaneously The limitation to the scope of the patents therefore cannot be interpreted as.It should be appreciated that for those of ordinary skill in the art, Under the premise of not departing from present inventive concept, various modifications and improvements can be made, these are all belonged to the protection scope of this patent. Therefore, the scope of protection shall be subject to the appended claims for this patent.

Claims (2)

1. An isosceles trapezoidal stick-slip piezoelectric linear actuator, characterized in that: it is mainly composed of a base (1), a slider (2), an isosceles trapezoidal stator (3) and a preloading mechanism (4); (2) and the preloading mechanism (4) are installed on the base (1), and the preloading mechanism (4) is used for preloading the isosceles trapezoid stator (3) and the slider (2); the isosceles trapezoid stator (3) It includes an isosceles trapezoid flexible mechanism (3-1) and four rectangular piezoelectric ceramic sheets (3-2), and the isosceles trapezoid flexible mechanism (3-1) passes through two mounting holes (3-1-6) It is fixed on the surface of the preloading mechanism (4); the isosceles trapezoidal flexible mechanism (3-1) is a flexible double rocker mechanism, wherein the horizontal axis (3-1-5) is a fixed frame, and the rod where the driving foot is located is a connecting rod, The left flexible beam (3-1-3) and the right flexible beam (3-1-4) are respectively pasted with left bending piezoelectric ceramics (3-2-1) and right bending piezoelectric ceramics (3-2-2) as Drive the rocker; when working, the four piezoelectric ceramic sheets (3-2) are excited by the same forward sawtooth wave signal, and the four piezoelectric ceramic sheets (3-2) generate co-directional polarization, and the left flexible beam (3-1- 3) and the right flexible beam (3-1-4) are bent and deformed by the piezoelectric ceramic sheet (3-2), and the imaginary motion of the contact point between the left driving foot (3-1-1) and the slider (2) The trajectory can be decomposed into displacements in the x and y directions. When the driving foot is in close contact with the slider, the imaginary movement trajectory of the contact point changes as the left driving foot (3-1-1) and the right driving foot (3-1). -2) Changes in the normal positive pressure and tangential friction force on the contact surface with the slider (2); in the "sticky" stage, that is, when the left driving foot (3-1-1) is in contact with the slider (2) , the imaginary trajectory of the contact point is a combination of positive x-direction and negative y-direction movements, and a large positive pressure will be generated between the left driving foot (3-1-1) and the slider (2), so a larger static friction will be generated between the two force to drive the slider (2) to move along the positive x-direction; in the "slip" stage, that is, when the left flexible beam (3-1-3) quickly recovers due to its own elasticity, the imaginary trajectory of the contact point is the negative x-direction and positive y-direction Synthesis of motion, at this time, there is a small positive pressure between the left driving foot (3-1-1) and the slider (2), and the kinetic frictional resistance between the two will be smaller, and the slider (2) is affected by it. The fallback is also smaller. 2. The isosceles trapezoidal stick-slip piezoelectric linear actuator according to claim 1, characterized in that: four piezoelectric ceramic sheets (3-2) are pasted in a manner having the same polarization direction, and are subjected to the same forward sawtooth wave. When the signal is excited, in the slow rising stage of the sawtooth wave signal, the left flexible beam (3-1-3) and the right flexible beam (3-1-4) are slowly bent and deformed, and the right driving foot (3-1-2) and the slider are (2) Separation, the left driving foot (3-1-1) and the slider (2) are mainly affected by the static friction force, and because the contact point has a negative y-direction displacement, that is, the left flexible beam (3-1-3) and the The slider (2) is more compact, and the positive pressure at the contact point becomes larger, so the static friction driving force is larger, and the load capacity is better; in the stage of rapid decline of the sawtooth wave signal, the left flexible beam (3-1-3) is due to its own elasticity. Return to the original state, the left driving foot (3-1-1) and the slider (2) are mainly affected by the dynamic friction force, at this time the contact point has a positive y-direction displacement, thereby reducing the positive pressure of the contact point, and there is a smaller The dynamic friction resistance makes the sliding block (2) smaller; when the four piezoelectric ceramic sheets (3-2) are excited by the same negative sawtooth wave signal, the sliding block (2) is driven by the right driving foot (3-1). -2) Action will produce negative x-direction movement.