DuraAct™— Piezoelectric Patch Transducers for Industry and ... · Piezoelectric components like...

DuraAct™—Piezoelectric Patch Transducers for Industry and Research

Piezo · Nano · PositioningPiezo · Nano · Positioning

www.piceramic.de

http://www.piceramic.com

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PI Brochure: DuraAct Piezoelectric Patch Transducers; piezocomposite transducers; adaptronics, commercial applications; aerospace, automotive, machinery;; equipment, building and structures, Smart Materials; P-876; P876

PI Ceramic (PIC) is the piezo-ceramic division of PhysikInstrumente (PI), the world-leading manufacturer of ultra-high-precision piezo nanoposi-tioning systems. Based onknowledge and expertisegained in more than 40 yearsof continuous research andmanufacturing of piezoelectricmaterials and components, PICeramic is a world-class sup-plier of high-performancepiezoelectric actuator andtransducer components andsubassemblies.

� State-of-the-Art Piezo Com-ponents, Ultrasonic Trans-ducers, Piezo Actuators andPiezo-System Solutions

� Design & Manufacture ofHigh-ReliabilityComponents for the KeyMarkets of Our Time

� Custom and Standard Solutions—Highly FlexibleProcessing Ensures RapidDelivery

� Custom Designs—All KeyTechnologies and Equip-ment In-House

� ISO 9001-2000 QualityCertified since 1997

Ultra-High-Precision Tech-

nology Years Ahead of Its Time

PI has a strategy of verticalintegration with all key tech-nologies developed and main-tained in the company. Directcontrol over every step fromconception to shipment per-mits optimizing quality andcost. As a customer, you, too, can profit from our longexperience in controlling andmeasuring motion at thenanometer level. PI can reactquickly to development andproduction needs of OEM cus-tomers—even for highly com-plex custom products and sub-assemblies.

Key Technologies Under One Roof:a Plus for Our Customers

INVENT GmbH is a 1996 spin-off from the DLR (GermanAerospace Center) Institute ofStructural Mechanics inBraunschweig. Now an estab-lished partner for the aero-space industry, INVENT offersqualified processes for plan-ning, design, engineering andmanufacturing—the funda-mentals of successful productdevelopment.

INVENT GmbH has earnedrenown as engineering special-ist for composite fiber tech-nologies. The company devel-ops structural components,applying their expertise in

fields ranging from structuralanalysis, construction methodsto series production. Anothermajor area of activity isresearch and development.There, the focus is on materialand process engineering,including finishing and coatingof composite fiber structures. The quality management sys-tem at INVENT has been DINEN 9100 certified since 2005.

Research for Industry

State-of-the-art PI Ceramicfacility in Lederhose Germany

hosts an extensive manufacturing operation,

R&D laboratories as well asadministration offices

PI headquarters

Cooperation

DuraAct™ patch transducersare based on a patenteddevelopment by the GermanAerospace Center (DLR). PICeramic (PIC) produces thepiezoceramic elements andhandles all sales under anexclusive agreement, whileINVENT GmbH puts togetherthe transducers.

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The development of self-cor-recting, adaptive systems isreceiving more and moreattention in modern industrialresearch. Structures using“smart materials” which inte-grate sensor and actuator func-tions are taking on growingimportance in this field. Thesesystems are designed to detectand react to changes in theiroperating environment, likeimpact, pressure or bendingforces.

With a long history as adaptivematerials, piezo actuators havebeen especially popular for themonitoring and active damp-ing of high-frequency vibra-tion. The novel DuraAct™ patchtransducers now offer a com-pact solution in this area.

Applied directly to a substrate,or used as part of the structureitself, DuraAct™ patch tranduc-ers can detect and producevibrations or contour deforma-

tions at the source, inside thestructure. The magnitude ofusable deflection dependsstrongly on the substrate prop-erties, and extends into themillimeter range.

Adaptronics—IndustrialApplications of Tomorrow

Piezoelectric components likethe DuraAct™ patch transducertransform electrical to mechan-ical energy and vice versa.Possible applications are inhigh-precision bender actua-tors, high-dynamics sensors oras power sources.

DuraAct™ patch transducersare extremely compact unitsbased on a thin piezoceramicfoil between two conductivefilms, all embedded in a ductilecomposite-polymer structure.In this way, the brittle piezo-ceramic is mechanically pre-

stressed and electrically insu-lated, which makes the trans-ducers so robust that they canbe applied on curved surfaceswith a bending radius as low as20 mm. The patch transducersare glued to the surface and canbe used for various purposes.

Even in high-dynamics applica-tions, the rugged designensures reliability, high resist-ance to damage and a lifetimewell over 109 cycles. Wear andfailure rates are low, as thesolid-state actuators contain nomoving parts.

Piezo-Electric All-Rounder—DuraAct™ Patch Tranducers

DuraAct™ patch transducerscan extract electric power frommechanical vibrations of up toseveral kilohertz, thus acting asenergy harvesting devices. The

power, in the milliwatt range,can supply miniature electron-ics like LEDs, sensors or miniRF transmitters for remote datatransfer.

Miniature Electric Generator forAutonomous Systems

DuraAct™ patch transducers tolerate bending radii as low as 20 mm (3/4 in.)


http://www.piceramic.de

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DuraAct™ technology allowshigh flexibility in actuatordesign. This means thatDuraAct™ is also ideally suitedfor research and prototyping.In addition to the range of stan-dard designs, highly individu-alized structural shapes can berealized to meet differentrequirements of geometry,flexibility, stiffness or operat-ing temperature.

Standard DuraAct™ patchtransducers consist of onepiezoceramic layer only. Forspecial applications, multilayerdevices can be made available.In an actuator, multiple layersresult in higher force genera-tion with the same operating voltage. If the layers are wired

separately, both sensor andactuator functionality can beused simultaneously.

The piezoelectric transducerscan be designed to fit the appli-

cation exactly, including eventransducers with arrays ofmultiple ceramic elements.Such custom products can beproduced very efficiently, evenin low quantities.

Depending on the application,different demands are made onthe electronics. To operate ahigh-precision, high-dynamicspositioner, a low-noise, broad-band amplifier is required.

Active vibration dampingrequires fast servo-control withbandwidth sufficient for close-coupling the generated force tothe structural mass to bedamped.

PI offers special, high-resolu-tion amplifier modules forDuraAct™ patch transducers,and can always create customversions to meet specialrequirements.

Tailored Control Electronics

Selection of custom modules

DuraAct™ Patch Transducers—Features and Advantages

Custom Versions forAny Application

High damage immunity

Choice of materials and geometries

Well-defined mechanical and electrical properties

Short lead-time availability

Compact

Long lifetime

High bandwidth

Customized solutions

Can be applied to curved surfaces

Constant & proven quality

Easy to use

Operation as actuator, sensor or power source

Multilayer module, e.g. for actuator-sensor combination

Highly flexible ceramic elements

Cost-effective


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Fig. 1a: Classical application of the direct piezo effect. Minute deformations of the substratecause displacements in the DuraAct™ patch transducer and produce an electric current pro-portional to the motion. DuraAct™ transducers can detect deformations—like those causedby bending strain or pressure—very precisely, even at high frequencies.

Application ExamplesSensor Mode

F

UU

F

UU

Fig. 1b: The same operating mode can be used with an array of several modules.

� Vibration damping applica-tions: good results can beachieved by combining apiezoelectric sensor with aservo-controller and havingthe sensor signal control an(external) damping mecha-nism.

Actuator Mode

U

F

Fig. 2: In actuator mode, DuraAct™patch transducers use the inversepiezo effect: they contract whenvoltage is applied. Affixed to a sub-strate material, a DuraAct™ patchtransducer acts as a bender

DuraAct™ patch transducersfeature a very high bandwidth.In combination with suitableelectronics (e.g. E-413.D2 fromPI) they can be used as high-dynamics positioners with sub-micron precision.

Whole areas can be surveyedwith an array of multiple mod-ules attached to various pointson the surface. Active monitor-ing, where some transducersare used as actuators while theothers detect the waves theygenerate, is also possible.Faults in the structural material,like microcracks, are detectedby comparing the signals withthose from an undamaged sys-tem.

UU

U

Fig. 3: Design principle for a healthmonitoring system: one DuraAct™patch transducer is controlled byan electronic amplifier (actuatorfunctionality) and induces vibra-tions in the substrate. An array oftransducers detects the vibrationsand transfers the signals to suitablecontrol electronics. Comparisonwith the signal pattern from anundamaged system gives informa-tion concerning the condition ofthe substrate.

� Structural Health Monitoring(SHM): DuraAct™ patchtransducers can be used tomonitor the functional andstructural integrity; the patchtransducers are either part ofthe structure itself, orembedded within it.

� Fast switching: DuraAct™patch transducers providefast response and long life-time and are ideal actuatorsfor these applications.

Structural Health Monitoring (SHM)—Damage Diagnosis

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Application Examples (cont.)Adaptive Systems Use Both Sensors and Actuators

� Active Vibration Damping: ADuraAct™ patch transduceris used as high-precisionsensor and high-performan-ce actuator, simultaneouslydetecting and dampingor eliminating undesirablevibrations in, for example,

rotating components. TheDuraAct™ sensor signalmay be used as powersupply for the same module, where it is fed back in with a phase shift.Multilayer ceramic designsmake for higher efficiency.

Adaptronics

The use in adaptive structures exploits both the sensor andactuator functionality of the DuraAct™ patch transducer. Assmart materials, they can adapt to varying environmental con-ditions like impact, bending or pressure. Adaptive materials areused in particular for vibration reduction in vehicles, and theiruse in mechanical engineering is growing.

Energy Harvesting

� DuraAct™ patch transdu-cers can provide power forlow-power electronics likesensors, making the de-velopment of autonomoussystems possible. A specialbranch of Structural HealthMonitoring (SHM) is

Wireless Health Monitoring.Here, a DuraAct™ patchtransducer can serve simul-taneously as shape-controlsensor and supply energyto a radio transmitter forremote data transfer.

� DuraAct™ patch transdu-cers may replace otherpower supply solutions inexisting applications.

F

Fig. 4: The ability of DuraAct™ transducers to convert mechanical to electrical energy makesthem ideal for satisfying power requirements of low-power electronics, and makes possibleconstruction of energy-autonomous systems

� Profile or shape control: Thesensor functionality is usedto detect a deformation, andthe actuator function tocounteract it. The resultingshape control is highly pre-cise, down to the submicronrange.


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Selection Guide

Model Dimensions Mass Active Capacitance Supply Lateral Free Lateral Blocking Young’s

(l x w x d) [g] Area [nF] Voltage Contraction/ Contraction Force Modulus

[mm] [cm2] (min/max) Voltage S0 FB [GPa]

[V] [(µm/m)/V] [µm/m] [N]

Custom modules

The modular design of theDuraAct™ technology opensa wide range of optimizationpossibilities concerning thefollowing features:

� Transducer geometry

� Flexibility and bending

� Operating temperature

� Insulating material

� Electrodes, shape and mate-rial

� Connection points, shapeand material

Custom Transducer Shapes

DuraAct™ Patch Transducers

Model Dimensions Mass Active Capacitance Supply Lateral Free Lateral Blocking Young’s

(l x w x d) [g] Area [nF] Voltage Contraction/ Contraction Force Modulus

[mm] [cm2] (min/max) Voltage S0 FB [GPa]

[V] [(µm/m)/V] [µm/m] [N]

P-876.A22 113 x 35 x 0.5 6.5 30 180 -100 to 400 1.3 650 265 23.3

P-876.A42 113 x 67 x 0.5 12.5 60 360 -100 to 400 1.3 650 527 24.2

P-876.A25 113 x 35 x 0.8 13.5 30 90 -250 to 1000 0.64 800 775 34.7

P-876.A45 113 x 67 x 0.8 27.0 60 180 -250 to 1000 0.64 800 1546 36.1

P-876.B12 61 x 55 x 0.5 5.5 25 150 -100 to 400 1.3 650 438 24.5

P-876.B22 113 x 55 x 0.5 10.0 50 300 -100 to 400 1.3 650 438 24.5

P-876.B42 113 x 107 x 0.5 20.0 100 600 -100 to 400 1.3 650 873 25.1

P-876.B15 61 x 55 x 0.8 11.5 25 75 -250 to 1000 0.64 800 1290 36.6

P-876.B25 113 x 55 x 0.8 21.5 50 150 -250 to 1000 0.64 800 1290 36.6

P-876.B45 113 x 107 x 0.8 43.0 100 300 -250 to 1000 0.64 800 2570 37.5

P-876.C12 81 x 30 x 0.5 4.0 17.5 10.5 -100 to 400 1.3 650 220 22.7

P-876.C22 153 x 30 x 0.5 7.5 35 210 -100 to 400 1.3 650 220 22.7

P-876.C42 153 x 57 x 0.5 15.0 70 420 -100 to 400 1.3 650 440 23.8

P-876.C15 81 x 30 x 0.8 8.2 17.5 53 -250 to 1000 0.64 800 650 33.8

P-876.C25 153 x 30 x 0.8 16.0 35 105 -250 to 1000 0.64 800 650 33.8

P-876.C45 153 x 57 x 0.8 31.5 70 210 -250 to 1000 0.64 800 1290 35.4

P-876.SP1 27 x 15 x 0.5 0.5 0.8 4.75 – – – – –

Coming Soon

P-876.A11 61 x 35 x 0.4 2.1 15 150 -50 to 200 1.6 450 90 16.4

P-876.A12 61 x 35 x 0.5 3.5 15 90 -100 to 400 1.3 650 265 23.3

P-876.A15 61 x 35 x 0.8 7.2 15 45 -250 to 1000 0.64 800 775 34.7

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P-876 DuraAct™ patch trans-ducers offer the functionality ofpiezoceramic materials as sensors and actuators as wellas for electrical charge genera-tion and storage. Used as bender actuators, they allowhigh deflections of up to 0.8 mmwith high force and high preci-sion. Other possible operationmodes of DuraAct™ transduc-ers are as high-dynamics sen-sors (e.g. for structural healthmonitoring) or for energy har-vesting.

Integration into Adaptive

Systems

With their compact design,DuraAct™ transducers can beapplied to structure areaswhere deformations are to begenerated or detected. For thispurpose the transducers can beaffixed to the surfaces of struc-tures or integrated as structuralelements themselves. Wholeareas can be monitored effec-tively by applying an array ofseveral modules to a surface.

DuraAct™ patch transducersare ideally suited for active andadaptive systems. Embeddedin a servo-control loop, theycan reduce vibrations and con-trol structures in the nanome-ter range.

Robust and Cost-Effective

Design for Industrial

Applications

The laminated design withpiezoceramic plate and poly-mers provide a mechanicallypreloaded and electrically insu-lated device for easy handling.P-876 patch transducers fea-

ture a rugged design with themechanical stability of a struc-tural material.

Energy Harvesting:

Self-Sustaining Systems in a

Small Package

One possible application ofDuraAct™ patch transducers isin the field of energy harvest-ing. Transformation ofmechanical vibrations of up tosome kilohertz into the corre-sponding potential differencecan yield electrical power inthe milliwatt range. This powercan supply miniature electron-ic devices like diodes, sensorsor even radio transmitters forremote data control.

DuraAct™ transducers can beoffered in highly customizedversions:

� Flexible choice of dimensions

� Flexible choice of thicknessand bending properties

� Flexible choice of piezo-ceramic materials and oper-ating temperature

� Various electrical connectiondesigns

� Combining sensor and actuator functions (multipleceramic layers)

DuraAct™ Piezoelectric Patch Transducers

P-876

Dimensions of the P-876 in mm

Ordering Information

P-876.A11

DuraAct™ Patch Transducer, 61 x 35 x 0.4 mm

P-876.A12


P-876.A15


Ask for custom designs!

Application Examples

� High-dynamics actuators

� Adaptive systems

� Vibration and noisecancellation

� Deformation control andstabilization

� Damage monitoring

� Energy harvesting

P-876.A12 and .A15 actuators. Golf ball for size comparison

� Actuator, Sensor or Energy Source

� Highly Formable Ceramics

� Can be Applied to Curved Surfaces

� Customized Solutions on Request

� Cost-Effective

Lateral contraction of a DuraAct™ patch transducer when voltage is applied

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Technical Data

P-876.A11 P-876.A12 P-876.A15 Tolerances

Operating voltage -50 to +200 V -100 to +400 V -250 to +1000 V

Motion and positioning

Lateral contraction, open-loop 400 µm/m 650 µm/m 800 µm/m min.1.6 µm/(H/m/V) 1.3 µm/(H/m/V) 0.64 µm/(H/m/V)

Mechanical properties

Holding force 90 N 265 N 775 N

Length 61 mm 61 mm 61 mm ±0.5 mm

Width 35 mm 35 mm 35 mm ±0.5 mm

Thickness 0.4 mm 0.5 mm 0.8 mm ±0.5 mm

Bending radius 12 mm 20 mm 70 mm max.

Drive properties

Piezo ceramic type PIC 252 PIC 255 PIC 255 Layer thickness: 100 µm Layer thickness: 200 µm Layer thickness: 500 µm

Electrical capacitance 150 nF 90 nF 45 nF ±20 %

Miscellaneous

Operating temperature range -20 to +150 (180) °C -20 to +150 (180) °C -20 to +150 (180) °C

Mass 2.1 g 3.5 g 7.2 g ±5 %

Voltage connection Solder pads Solder pads Solder pads

Recommended controller/driver E-413.D2 E-413.D2 E-508

Deflection of a bending transducer as a function of the substrate thickness for different materials. A bending transducer consists of a substrate with a P-876 actuator

(here: P-876.A15) glued to one side. A contraction of the actuator effects a deflection W Design principle of the transducer

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The E-413 is a stand-alone,amplifier board for bipolarPZTs. Three versions are avail-able: the E-413.00 (bench-top),the E-413.OE OEM version andthe E-413.D2 for DuraAct™patch transducers. The firsttwo can output and sink peakcurrents of 100 mA in a volt-age range of -250 to +250 V,corresponding to the standardrange of PI PICA™ Shear piezoactuators see page 1-24 ff.

The E-413.D2 is designed fordriving P-876 DuraAct™ piezo-electric patch transducers; itoffers a peak output power of50 W with an operating volt-age of -100 to +400 V.

Open-Loop Operation

E-413 piezo amplifier modulesprovide precision control forpiezo shear and bender actua-tors both in static and dyna-mic operation.

The output voltage is deter-mined by an analog signal atthe control input, combined

with an optional DC-offset(external potentiometer notincluded) amplified by factor50.

Remote Control via

Computer Interface

Optionally, digital control via aD/A converter is possible. Forseveral D/A boards fromNational Instruments, PI offersa corresponding LabVIEW™driver set which is compatiblewith the PI General CommandSet (GCS), the command setused by all PI controllers. Afurther option includes thepatented Hyperbit™ technolo-gy providing enhanced sys-tem resolution.

Operation / Contents of

Delivery

Only a single, unipolar, stabi-lized voltage input of 24 V isrequired to operate the E-413.An integrated DC/DC conver-ter generates the PZT operat-ing voltage and all other volt-ages used internally. All inputsand outputs are via the male,

32-pin, rear connector. Amatching female, 32-pin con-nector is included.

Please read general informa-tion on piezo amplifiers seepage 6-52.

E-413Compact Piezo Amplifier for DuraAct™ Patch Transducers and PICA™ Shear Piezo Actuators

� Peak Power to 50 W

� OEM Module / Bench-Top for PICA™ Shear Actuators

� OEM Module for DuraAct™ Piezoelectric Patch Transducers

OEM amplifier module E-413.D2 for DuraAct™ piezoceramic patch transducers

Ordering Information

E-413.D2

Piezo Amplifier for DuraAct™ PatchTransducers, -100 to +400 V

E-413.00

Piezo Amplifier for PICA™ ShearActuators, -250 to +250 V, Bench Top

E-413.OE

Piezo Amplifier for PICA™ ShearActuators, -250 to +250 V, OEM Module

Accessories:

E-500.ACD

CD with Driver Set for AnalogControllers

E-500.HCD

Hyperbit™ Functionality forEnhanced System Resolution(Supports certain D/A boards.)

E-413.OE OEM amplifier module (with heat sink) for PICA™ Shear piezo actuators

E-413: operating limits with various PZT loads, capacitance is measured in nF

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E-413.00 bench-top piezo amplifier for PICA™ Shear actuators

Technical Data

E-413.00 E-413.OE E-413.D2

Function Power amplifier for PICA™ Power amplifier for PICA™ Power amplifier for Shear piezo actuators, bench-top Shear piezo actuators, OEM module DuraAct™ piezoelectric patch

transducers, OEM module

Amplifier

Input voltage range -5 to +5 V -5 to +5 V -2 to 8 V

Output voltage range -250 to 250 V -250 to 250 V -100 to 400 V

Amplifier channels 1 1 1

Peak output power 50 VA 50 VA 50 VA

Average output power <12 VA <12 VA <6 VA

Peak current 100 mA 100 mA 100 mA

Average current 24 mA 24 mA 12 mA

Current limitation Short-circuit proof Short-circuit proof Short-circuit proof

Voltage gain 50 ±0.1 50 ±0.1 50 ±0.1

Ripple, noise, <10 kHz 100 mVP-P@100 nF 100 mVP-P@100 nF 100 mVP-P@100 nF

Amplifier resolution <10 mV <10 mV <10 mV

Input impedance 100 kΩ 100 kΩ 100 kΩ

Interface and operation

Piezo connector Conec Sub-D 5W1 with HV (rear) DIN 41612, 32-pin. (rear) DIN 41612, 32-pin. (rear)

Control input voltage SMB connector (rear) DIN 41612, 32-pin. (rear) DIN 41612, 32-pin. (rear)

Miscellaneous

Operating temperature range +5 °C to +50 °C +5 °C to +50 °C +5 °C to +50 °C(10 % derated over 40 °C) (10 % derated over 40 °C) (10 % derated over 40 °C)

Dimensions 220 x 105 x 54 mm 14T wide 3H wide 7T wide 3H wide

Mass 1.14 kg 0.8 kg 0.4 kg

Operating voltage 24 V / 2 A 24 V / 2 A 24 V / 1 A

Power consumption 48 W 48 W 24 W

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Tutorial

Working Principle

The term piezo is derived fromthe Greek word for pressure. In1880 Jacques and Pierre Curiediscovered that an electricpotential could be generatedby applying pressure to quartzcrystals; they named this phe-nomenon the piezoelectriceffect. Later they ascertainedthat when exposed to an elec-tric potential, piezoelectricmaterials change shape. Thisthey named the inverse piezo-electric effect.

The piezo effect is used for sen-sor functionality, while actua-tor behavior uses the inversepiezo effect.

The piezoceramic plates inDuraAct™ patch transducersresemble a capacitor. Theceramic acts as a dielectricbetween its metallized sur-faces. When voltage is applied,an electric field is createdinside the ceramic. The fieldcauses a uniform lateral con-traction of the ceramic perpen-dicular to the direction of theelectric field (Fig. 1). This beha-vior is called the transversepiezoelectric effect (d31 effect,Fig.2).

The electric field strengthdetermines the magnitude ofthe lateral contraction. This isthe key to simple control of the transducer modules. Whenthe modules are glued to a sub-strate, they effectively transferforce over the whole surface,not only at selected points, aswith conventional actuators.Conversely, DuraAct™ patchtransducers transform changesin shape to electric current,thereby enabling their use assensors or energy sources.

The piezoceramic response toa change of the electric field orto deformation is extremely

fast. Vibrations in the kilohertzrange can be produced ordetected. Different excitationvoltages are required and dif-ferent contraction amountspossible, depending on theceramic type and its dimen-sions. The correlation betweendisplacement and applied volt-age is not linear. A voltage-to-displacement curve with thetypical hysteresis behavior isshown in Fig. 3.

Fig. 1: Lateral contraction

Fig. 3: Piezo hysteresis

Fig. 2: d31 effect


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Piezo · Nano · PositioningPiezo · Nano · PositioningPiezo · Nano · Positioning

Technology

DuraAct™ patch transducersoperate as sensors with vary-ing bandwidths—reacting tomechanical strain like impact,bending or pressure—and ashigh-precision positioning orbending actuators.

The standard transducerdesign features a piezoceramicfoil with metalized surfaces forelectrical contact (Fig. 4). Thethickness of standard foils usedis typically 100 to 500 µm, witheven thinner layers possible.Without further processing,these piezoceramic elementsare brittle and difficult to han-dle. Embedding them in a poly-mer structure provides electri-cal insulation and mechanicalstability. The result is a modulethat is ductile and extremelyrobust.

An alternative design featuresmultiple layer piezoceramics,enhancing force generation forthe same operating voltage.

DuraAct™ patch transducersare solid state actuators andtherefore have no movingparts. Wear and failure ratesare low. Electrical contact isrealized by soldering, clampingor gluing leads to two pads.Connecting multiple layersseparately allows separation of the sensor and actuatorfunctionality, meaning that the transducer can be used assensor and actuator simultane-ously.

Fig. 4: DuraAct™ transducer design principle

Working Diagram

The actuator properties ofpiezoceramic transducers areessentially described by twoparameters: the blocking forceFB and the free displacement,S0. When a voltage U is appliedto the free (unblocked) actua-tor, it reaches its maximum dis-placement S0. The force re-quired to prevent any lengthchange at all is called the block-ing force, FB (Fig. 5).

A graph of applied force versusactuator displacement is calledthe actuator characteristiccurve (Fig. 7). It basically fol-lows the line passing throughthe points with 0 force and 0displacement described above.In most cases the actuator actsagainst an elastic structure,

e.g. when a spring or a metalsheet is deformed (Fig. 6). If theload is represented by a spring(characteristic curve of thespring) with stiffness of cF, theresulting operating point is theintersection of the load linewith the actuator characteristiccurve (Fig. 7). The most effec-tive operation occurs when theoperating point is in the middleof the characteristic curve.

Fig. 5: Parameter definitions

Fig. 6: Application of a spring force to an actuator

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Parameters for Bender Actuators

DuraAct™ actuators are usual-ly glued to a substrate andtransfer the contraction not at afew attachment points, butover the whole surface. In sucha configuration, the DuraAct™/substrate combination acts asa bender actuator. Bender actu-ators provide fast, high-preci-sion and repeatable deflectionand are used in a wide range ofapplications, e.g. in printers,valves, and in the textile indus-try. DuraAct™ patch transduc-ers are based on the transversepiezo effect, and therefore con-tract with an electric fieldapplied. The bender flexes andexerts a normal force as shownin Fig. 8. For the free, un-blocked bender, the free deflec-tion is W0. The force requiredto reduce the deflection to zerois called the bender blocking

force FBW. It is significantlysmaller than the actuatorblocking force. The linethrough these two points,gives the characteristic curvefor the bender. Fig. 9 and 10show curves relating the maxi-mum deflection W0 and themaximum force FBW to the sub-strate thickness and elasticity.These diagrams show the actu-al deflections and forces meas-ured with 50 mm substratesamples made of differentmaterials and a P-876.A15DuraAct™ patch transducer.Together with the characteristiccurve for the DuraAct™ alone,the bender characteristics formthe basis for effectively esti-mating the actuator perform-ance in a specific application.PI therefore includes thesecurves on all datasheets.

Fig. 10: Bender actuator blocking force

Fig. 8: Bender actuator characteristics

Fig. 9: Free deflection of bender actuators

Fig. 7: Characteristic curve with spring load line


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Piezo · Nano · Positioning

Power Requirements

To determine the requiredelectrical power for successfulactuator operation, the elec-trical capacitance must beknown. Typical DuraAct™ ca-pacitances are in the nanofaradrange and can be found in thedatasheets.

The electrical capacitance, C,depends on the piezoceramictype, thickness and area. For anestimation of the average elec-trical power, Pm, knowledge ofthe operating voltage rangeand the excitation frequency isnecessary.

Pm = C · f · Uh2

Pmax = Pm · π

PICMA®

Multilayer Bender Actuators

In addition to DuraAct™ patchtransducers, PI manufactures alarge variety of high-perfor-mance, high-load piezo actua-tors (multilayer stacks, high-voltage stacks, multilayer ben-ders, etc.)

f: FrequencyUh: Voltage swing

The maximum power requiredPmax is then just the averagepower times pi (π):

PICA™ Piezo Tube Actuators

PICA™ High-Force Piezo Stack Actuators

(to 10 Ton load capacity)

PICMA® Multilayer Piezo Stacks


Piezo · Nano · Positioning

www.piceramic.de

Headquarters

GERMANY

PI Ceramic GmbH

Lindenstr.D-07589 LederhoseTel: +49 (36604) 882-0Fax: +49 (36604) [email protected]

Subsidiaries

JAPAN

PI Japan Co., Ltd.

Akebono-cho 2-38-5Tachikawa-shiJ-Tokyo 190Tel: +81 (42) 526 7300Fax: +81 (42) 526 [email protected]

PI Japan Co., Ltd.

Hanahara Dai-ni Building, #7034-11-27 Nishinakajima,Yodogawa-ku, Osaka-shiJ-Osaka 532Tel: +81 (6) 6304 5605Fax: +81 (6) 6304 [email protected]

CHINA

Physik Instrumente

(PI Shanghai) Co., Ltd.

Building No. 7-301Longdong Avenue 3000201203 Shanghai, ChinaTel: +86 (21) 687 900 08Fax: +86 (21) 687 900 [email protected]

FRANCE

PI France S.A.S.

32 rue DelizyF-93694 Pantin CedexTel: +33 (1) 481 039 30Fax: +33 (1) 481 008 [email protected]

Physik Instrumente (PI)

GmbH & Co. KG

Auf der Römerstr. 1D-76228 Karlsruhe/PalmbachTel: +49 (721) 4846-0 Fax: +49 (721) [email protected] · www.pi.ws

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USA (East) & CANADA

PI (Physik Instrumente) L.P.

16 Albert St. Auburn, MA 01501Tel: +1 (508) 832 3456Fax: +1 (508) 832 [email protected]

USA (West) & MEXICO

PI (Physik Instrumente) L.P.

5420 Trabuco Rd., Suite 100 Irvine, CA 92620Tel: +1 (949) 679 9191Fax: +1 (949) 679 [email protected]

GREAT BRITAIN

Lambda Photometrics Ltd.

Lambda HouseBatford MillGB-Harpenden, HertfordshireAL5 5BZTel: +44 (1582) 764 334Fax: +44 (1582) 712 [email protected]

ITALY

Physik Instrumente (PI) S.r.l.

Via G. Marconi, 28I-20091 Bresso (MI)Tel: +39 (02) 665 011 01Fax: +39 (02) 665 014 [email protected]

Program Overview

� Piezoelectric Actuators

� Piezo Nanopositioning Systems and Scanners

� Active Optics / Tip-Tilt Platforms

� Capacitive Sensors

� Piezo Electronics: Amplifiers and Controllers

� Hexapods

� Micropositioners

� Positioning Systems for Fiber Optics, Photonicsand Telecommunications

� Motor Controllers

� PILine® High-Speed Ceramic Linear Motors

For more information on piezoceramic materials andcomponents, see the PI Ceramic catalogs and Website(www.piceramic.de).

For more information on these and other PI productlines, see the Physik Instrumente (PI) Nanopositioningcatalog and website (www.pi.ws).

http://www.piceramic.com

http://www.pi-japan.jp

http://www.pi-china.cn

http://www.polytec-pi.fr

http://www.pi.ws

http://www.pi-usa.us

http://www.pionline.it

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