CN1172778C - Integral tpe microdisplacement, force three-dimension flexible driving amplifying and steering mechanism - Google Patents

Abstract

The present invention belongs to the technical field of micro nanometers, and comprises a micro drive, a flexible hinge, a positioning structure and an adjusting knob, wherein the micro drive comprises two smooth top surface and bottom surface having flatness requirements, the micro drive is embedded in the flexible hinge, the bottom surface of the micro drive contacts the adjusting knob arranged in the flexible hinge, and the top surface of the micro drive is connected with the flexible hinge through the positioning structure arranged in the flexible hinge. The present invention has the advantages of compact structure, few transmitting links of movement and force, high reliability and small non-linear error. Simultaneously, the present invention assures the relative reduction of mechanism microminiaturization and needed operating spaces.

Description

Integral tpe microdisplacement, force three-dimension flexible drive and amplify and steering mechanism

Technical field

The invention belongs to micro-nano technical field, particularly be applied to the structural design of the micro element of ultraprecise processing, microposition, little assembling, microrobot etc.

Background technology

Micro-nano technology is the high-tech area of emerging, a multidisciplinary intersection, it compiles the scientific and technical colony of (comprise intersection, different levels) that newly grow in electronics, machinery, material, manufacturing, measurement and physics, chemistry and the biology small and microscopic fields, is considered to the core technology of 21 century.In MEMS (micro electro mechanical system) (MEMS) field, micro-nano technology relates to different research directions such as little processing, little assembling, micro element making and microrobot.Separate mechanism module is adopted in the realization of multinomial functions such as driving, amplify and turn in the prior art at present, and structure is huge, and intermediate link is many, and cumulative errors is big.Wherein traditional motor-driven, physical dimension is bigger, poor stability, resolution are low, for example the common step angle of stepper motor greatly about 1 degree (°) about, and in MEMS (micro electro mechanical system) or micro-nano technical field, the degree of accuracy of angle is often with second (") be the order of magnitude, visible traditional type of drive can not satisfy the requirement in modern technologies field far away.Enlargers such as gear commonly used or lever transmission, motion is many with the force-transmitting ring joint, reliability is low, nonlinearity erron is big, degree of accuracy is low, directly influence output displacement resolution.Common output commutation is the output of independently finishing a plurality of direction displacements and power by multiloop loop system in three dimensions, and the operating space that needs is big, and this has limited its practical application and expansion in microscopic techniques fields such as micrometer/nanometers.

Summary of the invention

The objective of the invention is for overcoming the weak point of prior art, a kind of integral tpe microdisplacement, force three-dimension flexible driving amplification and steering mechanism are proposed, has compact conformation, motion is few with the transmission link of power, the reliability height, nonlinearity erron is little, can guarantee the microminiaturization of mechanism and the relative plurality of advantages of dwindling in action required space simultaneously.

A kind of integral tpe microdisplacement that the present invention proposes, force three-dimension flexible drive and amplify and steering mechanism, it is characterized in that, comprise microdrive, flexible hinge, location structure, adjustment knob; Said microdrive comprises two smooth top face and the bottom surfaces that have flatness to require, this microdrive is embedded in this flexible hinge, the bottom surface of this microdrive contacts with adjustment knob in being arranged on this flexible hinge, and the end face of this microdrive is connected with flexible hinge by the location structure that is arranged in this flexible hinge; Said flexible hinge is made up of push rod, pull bar, horizontal push rod, take-off lever, turning-bar and fixed bar six part hinge-rods.

Said microdrive can adopt piezoceramic material, electrostriction material or electromagnetic material to make.Said microdrive can be hexahedron or right cylinder.

Said flexible hinge can adopt monocrystalline silicon, polysilicon, steel or high duty alloy material to make.Be connected to a polyhedral global shape by the Thin Elastic arm respectively between each hinge-rod; On the fixed bar of said flexible hinge, can there be three radiuses to equate the through hole that is triangularly arranged, be used for fixing whole compliant mechanism.

Said location structure can be a spherical ball, 1/6 of the desirable microdrive end face of its radius width; Be to guarantee stable position, with the push rod of the contacted flexible hinge of this location structure, an opening " V " shape groove relative with ball arranged, its circumradius is identical with ball.

Said adjustment knob top can be six prismatics, and the lower end can be cylindric, has fine thread, with the threaded hole of the fixed bar of flexible hinge tolerance fit is arranged.

The present invention a kind ofly has driving, amplifies and output such as turns at the integrated compliant mechanism of multinomial function micrometric displacement and power, and overall dimensions can be set according to the displacement output quantity and the resolution sizes of compliant mechanism.Each hinge-rod size of flexible hinge is by the displacement amplification ratio decision of whole compliant mechanism.The output displacement of the different entire mechanism of flexible hinge material and power are all with respective change.Flexible hinge can be realized by Special Working Technology technology such as microfabrication or Laser Processings.Satisfying at the through hole radius that three equal and opposite in directions on the fixed bar of flexible hinge are triangularly arranged under the prerequisite of requirement of mechanical strength and be proportionate relationship with the compliant mechanism size.Whole compliant mechanism is as general as hexahedron, and size can be exported size according to displacement and manufactures different stage: small-sized, microminiature, miniature etc.

Work structuring principle of the present invention is: in the compliant mechanism course of work, utilize inverse piezoelectric effect or electrostriction principle, input stable DC voltage acts on microdrive, produce the micrometric displacement and the power of initial driving, and micrometric displacement and power are passed to the push rod of flexible hinge by the detent mechanism that links to each other with microdrive, through the amplification modules at different levels and the steering module of flexible hinge, amplify and turn to, micrometric displacement and power that output at last meets design requirement.

Effect of the present invention:

Flexible hinge structure based on elastic deformation in the mechanism of the present invention can realize not having machinery friction, no gap, high precision and stability, and volume is little, and the amplification ratio height is applicable to MEMS (micro electro mechanical system); Little piezoelectric/electrostretch device integrated makes that mechanism drives that resolution height, load-bearing capacity are big, output displacement accuracy height, good stability, all has wide practical use at aspects such as China's micromechanics Precision Machining and micro-nano technology.

The amplification ratio of this mechanism can reach 105;

The output displacement can reach 1.68mm;

Displacement resolution can reach 1 μ m;

Output micrometric displacement and Li Ke transform in surface level and vertical plane.

Description of drawings

Fig. 1 is that schematic perspective view is looked on an embodiments of the invention structure left side;

Fig. 2 is that schematic perspective view is looked on the embodiments of the invention structure right side;

Fig. 3 is a fundamental diagram of the present invention;

Fig. 4 is a flexible hinge simplified design mathematical model synoptic diagram of the present invention;

Fig. 5 is a mechanism displacement scaling schematic diagram calculation of the present invention;

Fig. 6 is the software design process flow diagram of present embodiment;

Fig. 7 is an embodiments of the invention structural plan synoptic diagram.

Embodiment

Below in conjunction with each accompanying drawing a kind of preferred embodiment of the present invention is described in detail.

By Fig. 1, Fig. 2 and shown in Figure 7, embodiment mechanism is by four most of compositions such as microdrive 1, flexible hinge 2, location structure 3, adjustment knobs 4, and wherein flexible hinge 2 comprises: push rod 21, pull bar 22, horizontal push rod 23, take-off lever 24, turning-bar 25 and fixed bar 26 and the structures such as Thin Elastic arm that connect these hinge-rods.Microdrive 1 comprises two planes that have flatness to require up and down: bottom surface 12 and end face 11, wherein bottom surface 12 selects button 4 to contact with adjustment, and by adjusting the output pretightning force that knob 4 is regulated microdrive 1,11 of end faces pass through location structure 3 and are connected with " V " type groove at flexible hinge push rod 21 middle parts.Flexible hinge 2 is the one-piece constructions that processed by a block of material, relies on the Thin Elastic arm to link to each other between each ingredient, and transmits displacement and power that microdrive 1 produces, shown in C among Fig. 7.Push rod 21 is a hexahedron, and its middle part cuts out " V " shape groove in the place that links to each other with location structure 3, is shaped as equilateral triangle, and circumradius and location structure are measure-alike.The processing purpose of " V " type groove is in order to guarantee location structure 3 stable position in the compliant mechanism course of work.In the displacement transmittance process, push rod 21 has amplification, and enlargement factor is relevant with the position of the relative push rod of " V " type groove two ends Thin Elastic arm 213 and 27.The pull bar 22 that links to each other with push rod 21 is shaped as hexahedron, and it does not have the scaling effect to displacement and power, only is a transmission link that displacement and power is delivered to horizontal push rod 23 from push rod 21.Horizontal push rod 23 is shaped as step, and why processing a step is to consider for the process equipment and the processing technology requirement thereof of whole compliant mechanism, if conditions permit can not process this step.Horizontal push rod 23 links to each other by Thin Elastic arm 28 with pull bar 22, is connected by Thin Elastic arm 210 with turning-bar 25, is connected by Thin Elastic arm 29 with fixed bar 26.The relative distance of Thin Elastic arm 29 and Thin Elastic arm 28 and 210 is determining displacement and the power scaling ratio when pull bar 22 is delivered to turning-bar 25, and it is the closer to pull bar 22, and the amplification ratio of displacement is big more, otherwise opposite.Turning-bar 25 is little hexahedron, as shown in Figure 1: two Thin Elastic arms 210 that link to each other with turning- bar 25 and 211, trend are vertical mutually, its objective is the three dimensions conversion that is used for realizing displacement and power, promptly forward vertical direction to from surface level, it does not have the scaling effect to displacement and power.Take-off lever 24 has two steps of size, and the small stair of front links to each other with other mechanism for convenience of this compliant mechanism and designs, and it highly is determined on a case-by-case basis; The big step of back is for displacement and power are produced certain scaling.Fixed bar 26 links to each other with microdrive 1, adjustment knob 4 and push rod 21, horizontal push rod 23, take-off lever 24 etc., is the primary structure part of entire mechanism.With reference to the size of microdrive 1, on fixed bar 26, excise one that shape, size with it are complementary, so that microdrive 1 is embedded wherein.On fixed bar 26, also have three through holes that equal and opposite in direction is triangularly arranged, be used for fixing whole compliant mechanism.The same with horizontal push rod 23, the steps below the fixed bar 26 also are to consider for the angle of processing technology, if process equipment allows, can not cut this step.Location structure 3 is to be the spherical ball of radius with 1/6 of microdrive 1 top width, is used for connecting " V " type groove of the push rod 21 of the end face 11 of microdrive and flexible hinge.The shape of adjusting knob 4 is similar to screw rod, and the top is six prismatics, and the lower end is cylindric, has fine thread, carries out tolerance fit with the threaded hole of flexible hinge fixed bar 26.

Present embodiment overall dimensions: length * wide * height=115 * 83 * 10mm ³Microdrive adopts piezoceramic material, and length and width are 25mm, and maximum output displacement is 16 μ m.The flexible hinge material adopts the high-quality steel, processes by line cutting technology.Flexible hinge push rod 21 width are 8mm, its " V " type groove with about the ratio of distance of two sections Thin Elastic arms 213,27 be 20: 80; The length of pull bar 22 * wide=30 * 10mm ²The length of horizontal push rod 23 * wide=80 * 10mm ², bench height is 5mm, the Thin Elastic arm 29 that is attached thereto to the ratio of the distance of the Thin Elastic arm 210,28 at two ends, the left and right sides is: 60: 10; The length of turning-bar 25 * wide * height=10 * 5 * 5mm ³The length of take-off lever 24 small stairs * wide *=10 * 10 * 14mm ³, the horizontal range between step center and the Thin Elastic arm 212 is 15mm, and the vertical range between the Thin Elastic arm 211 is 5mm.

The elastic modulus E of steel: 2.1 * 10 ⁴Kg/mm ²

Compliant mechanism hinge arc radius R:1.5mm;

Compliant mechanism hinge minimum thickness t:1.0mm;

Compliant mechanism hinge minimum widith b:10mm;

Power supply input: 0～300V high voltage regulated power supply;

Mechanism's amplification ratio: $\frac{(20+80)}{20}\×\frac{(10+60)}{10}\×\frac{15}{5}=105;$

Output displacement: 1.68mm;

Power output: 2.38kg;

This exemplary application is in the micro element assembly system, as the inching gear of little assembly ware.Satisfy little assembly system micrometric displacement, multiple degrees of freedom precision stage opposing connection Z axle rotation calibration θ resolution 30 in the practical application " accuracy requirement, effective.

The foregoing description is small-sized compliant mechanism, according to the principle of the invention, dwindles the relative size of each ingredient of mechanism, can design and produce out equally micrometric displacement and power are had driving, the microminiature and the miniature flexible mechanism of function such as amplify, turn to.

Work structuring principle of the present invention is as shown in Figure 3: utilize inverse piezoelectric effect or electrostriction principle, outside input stable DC voltage acts on microdrive, produce micrometric displacement and power, and pass to flexible hinge, drive, amplify and turn to by detent mechanism.Flexible hinge 2 is divided on function: one-level is amplified (I), secondary amplifies (II), three grades of amplifications (III) and output and turns to four modules such as (IV), as shown in Figure 3, wherein (I), (II) and (III) the multistage amplification of realization microdrive 1 output micrometric displacement, (IV) then be used for finishing micrometric displacement and the conversion of power from the surface level to the vertical direction in the three dimensions, and then realized that micrometric displacement, force three-dimension flexible drive amplification and turn to function.

Usually the method complexity of hinge design will be finished by a large amount of hand computations, and precision and accuracy are difficult to guarantee.Given this, the present invention goes back the flexible hinge software design theoretical formula of independently having derived.Fig. 4 is flexible hinge 2 simplified design mathematical models, profile line partly is the cross section of flexible hinge Thin Elastic arm, α is the angle of interior cross section of polar coordinate system and polar axis shaft, θ is the corner of flexible hinge, and R is that flexible hinge arc radius, t are that flexible hinge minimum thickness, b are the width of flexible hinge.According to Fig. 4 mathematical model, utilize the Rombers numerical integration method can calculate the rotation stiffness coefficient of flexible hinge on computers.Fig. 4 is a flexible hinge simplified design model, and the part of beating profile line among the figure is the cross section of Thin Elastic arm, and wherein R is that the arc radius of flexible hinge Thin Elastic arm, minimum thickness, the b that t is the Thin Elastic arm are the width of Thin Elastic arm.This model is whole compliant mechanism design, check is calculated and the basis of the derivation of equation.

Fig. 5 is compliant mechanism displacement scaling schematic diagram calculation, wherein a ₀, a ₁, b ₀, b ₁, c ₀, c ₁Represent the relative distance between flexible hinge 2 each Thin Elastic arms respectively, can calculate the design parameters such as total amplification ratio of entire mechanism by these relations.Fin represents the output of microdrive 1, and its application point is at " V " of flexible hinge push rod 21 type groove place, and Fout represents the output of flexible hinge 2, i.e. the output of whole compliant mechanism.

Fig. 5 is a mechanism displacement amplification ratio computation structure principle, a ₁" V " the type groove and the Thin Elastic arm 213 of expression flexible hinge push rod 21, a ₀The distance of expression Thin Elastic arm 27 and Thin Elastic arm 213, b ₁The distance of expression Thin Elastic arm 29 and Thin Elastic arm 28, b ₀The distance of expression Thin Elastic arm 210 and Thin Elastic arm 28, c ₁Expression Thin Elastic arm 211 and the distance of Thin Elastic arm 212 in vertical plane, c ₀The center and the distance of Thin Elastic arm 212 in surface level of the small stair of the take-off lever 24 of expression flexible hinge 2.Can calculate the total amplification ratio and the maximum parameters such as displacement, power output of exporting of whole compliant mechanism by these size relationships.Fin represents the output of microdrive 1, and its application point is at " V " of flexible hinge push rod 21 type groove place, and Fout represents the output of flexible hinge 2, i.e. the output of whole compliant mechanism, and its position is in the center of flexible hinge take-off lever 24 small stairs.

(1) design parameters

Material permissible stress: σ _P0Material yield stress: σ _S0Microdrive maximum driving force: Fmax ₁The maximum output of microdrive displacement: Smax ₁Flexible hinge radius: R; Flexible hinge minimum thickness: t; Flexure hinge mechanism width: b; Rotation stiffness: K; Number of stages of amplification: N; Lever size array: R[N] [2]; Total amplification ratio: Rmax; Amplification ratio array: Ratio[N]; Lever corner array: A[M], M=(N-1)+N; Actual maximum output displacement: Smax ₂The power of actual maximum output: Fmax ₂Hinge calculated stress: σ ₀The required driving force of hinge: Fmax ₃

(2) computing formula

The rotation stiffness coefficient k

$k=1/{\∫}_0^{\mathrm{\π}}\frac{12R\sin \mathrm{\α}}{\mathrm{Eb}{(2R+t-2R\sin \mathrm{\α})}^3}\mathrm{d\α}------\left(1\right)$

Total amplification ratio

$R\max =\underset{i=1}{\overset{N}{\mathrm{\&Pi;}}}\mathrm{Ratio}[i-1]=\frac{R[i-1]\left[0\right]}{R[i-1]\left[1\right]}=\frac{a_0}{a_1}\&CenterDot;\frac{b_0}{{\mathrm{<figure-callout\; id="1"\; label="b"\; filenames="C0010776100091.png"\; state="\{\{state\}\}">b</figure-callout>}}_1}\&CenterDot;\frac{c_0}{c_1}----\left(2\right)$

The maximum output of hinge displacement

Smax ₂＝Smax ₁×Rmax (3)

The hinge corner

$A\left[0\right]=\frac{{S\max }_1}{R\left[0\right]\left[1\right]}---\left(4\right)$

$A\left[i\right]=\frac{\mathrm{Sma}{x}_1\underset{j=0}{\overset{i-1}{\mathrm{\&Pi;}}}\mathrm{Ratio}\left[j\right]}{R\left[i\right]\left[1\right]},i=\mathrm{1,2},...,N-1--------\left(5\right)$

A[N+i]＝A[i+1]-A[i] i＝0，1，...，N-2 (6)

The power of the maximum output of hinge

${F\max }_2=\frac{K}{{S\max }_2}\&times;(\underset{i=0}{\overset{N-1}{\mathrm{\&Sigma;}}}A{\left[i\right]}^2+\underset{i=0}{\overset{N-2}{\mathrm{\&Sigma;}}}A{[N+i]}^2)-----\left(7\right)$

The required maximum driving force of hinge

Fmax ₃＝Fmax ₂×Rmax (8)

The flexible hinge calculated stress

${\mathrm{\&sigma;}}_0=\frac{M\max }{W}$

$=\frac{K\&times;\mathrm{Max}\left(\right[A\left[i\right]],i=\mathrm{0,1},...,M)}{{\mathrm{<figure-callout\; id="2"\; label="bt"\; filenames="C0010776100091.png"\; state="\{\{state\}\}">bt</figure-callout>}}^2/6}---\left(9\right)$

(3) design is checked

With the above design calculation theory formula of mechanism's actual structure parameters substitution, if satisfy following relation:

σ ₀＜σ _p0；σ ₀＜σ _s0 (10)

Fmax ₃＜Fmax ₁ (11)

Then the expression design meets the requirements.

Present embodiment according to the compliant mechanism software flow of above-mentioned computing formula design as shown in Figure 6.At first counter Counter, maximum cycle Max supervisor control variable are carried out initialization, import parameter index and accuracy class e then.The mechanism design basic parameter mainly comprises the size of hinge radius R, thickness t, width b, hinge-rods at different levels and the elastic modulus E of compliant mechanism material etc., the basis that the input of these design parameters is carried out various calculating, conversion in the design cycle after being.After the preliminary work of software design is finished, below just can calculate the maximum stress σ of flexible hinge stiffness coefficient k, displacement amplification ratio R, rotational angle theta, output displacement Smax, power output Fmax and compliant mechanism material therefor according to the computing formula that the present invention derived.The current cycle index of whole flow process is shown by counter Counter, if in the maximum cycle Max that sets, computing parameter satisfies conditions such as checking relational expression and accuracy requirement, the entire mechanism software design is finished, otherwise, revise maximum cycle and design parameters and carry out designing and calculating again.Specifically may further comprise the steps:

The first step is that the control variable of program run is carried out initialization: Counter puts 0 with programmable counter, and sets the maximum cycle Max of a mechanism design.Second step was input design parameters index and accuracy class e, referred to utilize the accuracy class e of output area, resolution technique index and the design parameters numerical evaluation of micrometric displacement S, power F that interactive mode finally will reach this compliant mechanism to be input in the software by graphic interface.The result of calculation of the high more design parameters of accuracy class e is accurate more, but correspondingly computing time long more.The 3rd step was an input mechanism design basic parameter, comprised radius R, thickness t, the width b of flexible hinge, the size a of hinge-rods at different levels ₀, a ₁, b ₀, b ₁, c ₀, c ₁And the elastic modulus E of compliant mechanism material etc.More than three the step be the design preliminary preparation, below according to theoretical formula that the present invention derives, carry out analytical calculation.The 4th step was that control variable of program counter Counter is added 1, and the number of times of expression compliant mechanism program design begins to increase progressively.The 5th step was compared the maximum cycle Max that sets in counter Counter and the program circuit, if the value of Counter is greater than Max, expression compliant mechanism designing and calculating has surpassed the cycle index that sets, still do not reach design parameters index and accuracy requirement, have to carry out for the 6th step this moment, revises design parameters index and precision; If the value of Counter is not more than Max, then carry out following analytical calculation.The 7th step was to call formula (1) to calculate flexible hinge rotation stiffness coefficient k; The 8th step was to utilize formula (2) to calculate flexible hinge displacement amplification ratio R; The 9th step was to utilize formula (3) to calculate the maximum output of compliant mechanism displacement Smax ₂The tenth step was to utilize formula (4)～(6) to calculate the rotational angle theta of each hinge-rod of flexible hinge; The 11 step was to utilize formula (7) to calculate the maximum power output Fmax of compliant mechanism ₂The 12 step was to utilize formula (8) to calculate compliant mechanism to produce maximum output displacement Smax ₂The maximum driving force that microdrive need provide; The 13 step was to utilize formula (9) to calculate the maximum stress σ of compliant mechanism material therefor.The 14 step was to utilize the result that several steps of front calculate, requirement according to formula (10), (11), carry out analysis and judgement, if the result satisfies the relation of (10) and (11), represent that whole gentle shape mechanism software design finishes, otherwise, by the 15 step, the design analysis that " correction design parameters " feedback element is carried out compliant mechanism again calculates, till making it.

Claims (7)

1, a kind of integral tpe microdisplacement, force three-dimension flexible drive and amplify and steering mechanism, it is characterized in that, comprise microdrive, flexible hinge, location structure, adjustment knob; Said microdrive comprises two smooth top face and the bottom surfaces that have flatness to require, this microdrive is embedded in this flexible hinge, the bottom surface of this microdrive contacts with adjustment knob in being arranged on this flexible hinge, and the end face of this microdrive is connected with flexible hinge by the location structure that is arranged in this flexible hinge; Said flexible hinge is made up of push rod, pull bar, horizontal push rod, take-off lever, turning-bar and fixed bar six part hinge-rods.

2, amplification as claimed in claim 1 and steering mechanism is characterized in that, said microdrive adopts piezoceramic material, electrostriction material or electromagnetic material to make.

3, amplification as claimed in claim 1 and steering mechanism is characterized in that, said microdrive is hexahedron or right cylinder.

4, amplification as claimed in claim 1 and steering mechanism is characterized in that, said flexible hinge can adopt monocrystalline silicon, polysilicon, steel or alloy material to make.

5, amplification as claimed in claim 1 and steering mechanism is characterized in that, are connected to a polyhedral global shape by the Thin Elastic arm respectively between each hinge-rod; On the fixed bar of flexible hinge, there are three radiuses to equate the through hole that is triangularly arranged, are used for fixing whole compliant mechanism.

As claim 1 or 5 described amplification and steering mechanism, it is characterized in that 6, said location structure is a spherical ball, 1/6 of the desirable microdrive end face of its radius width; With the push rod of the contacted flexible hinge of this location structure, an opening " V " shape groove relative with ball arranged, its circumradius is identical with ball.

As claim 1 or 5 described amplification and steering mechanism, it is characterized in that 7, said adjustment knob top is six prismatics, the lower end is cylindric, has fine thread, with the threaded hole of the fixed bar of flexible hinge tolerance fit is arranged.

Images