Date post: | 21-Apr-2015 |
Category: |
Documents |
Upload: | chunxiao-yan |
View: | 253 times |
Download: | 9 times |
Overview on piezoelectric actuators, mechanisms & motors with their related driving electronics:
Technology & Applications
04/06/2010 1 Day Piezo Training 2010 2
Topics overview
1 / Piezo materials for actuators
1.1/ Piezo theory & properties
1.2/ Multilayer ceramic 1.2.1 /current properties, trends, perspectives,1.2.2 / Reliability aspects,
2 / Piezo actuators & mechanisms
2.1/ Internally & externally leveraged piezo actuators,2.2/ Piezo mechanisms,
3 / Driving and control of piezo actuators
3.1 / Basic of amplifiers 3.2 / Static & Dynamic conditions
4 / How to choose an actuator & its related electronics ?
4.1 Exercises
4.2 Demonstration
5/ Piezomotors5.1 / Inchworm and Inertial step motors5.2 / Resonant structure
5.2.1 / example of motors5.2.1 / modelling techniques
5.3 / Tribology of piezo motors5.4 / Driving of piezo motors
6 / Applications & references
04/06/2010 1 Day Piezo Training 2010 3
Piezoelectricity Theory & Properties
04/06/2010 1 Day Piezo Training 2010 4
Piezoelectricity : an overview
Materials aspectsEquationsMaterials constantsTechnological aspectsIllustrative exampleElectromechanical analogy
Piezo electric ceramics & magnetostrictive alloys
04/06/2010 1 Day Piezo Training 2010 5
Various effects in materials
Charge current Magnetisation Strain Temperature Light
Electrical field
Permittivity Conductivity
Elec-mag effect
Inverse piezo effect
Elec. Caloric effect
Elec. Optic effect
Magnetic field
Mag-electric effect
Permeability Magneto-striction
Mag.caloric effect
Mag.optic effect
Stress Direct Piezo-electric effect
Direct Piezo-magnetic effect (biased mat.)
Elastic constant
_ Photoelastic effect
Heat Pyroelectric effect
_ Thermal expansion
Specific heat
_
Light Photovoltaic effect
_ Photostriction _ Refractive effect
"Smart" materials refer to materials having a non - diagonal effect (sensing or actuating functions).
04/06/2010 1 Day Piezo Training 2010 6
Active strains of active materials
Applying a field (E or H) on an free sample, it deformsSmall deformation in the elastic domainStrain = relative expansion : S = δL / L
Expansion = positive strain / Contraction = negative strainsUnits : ppm= 10-6 or % = 10-2
Typical active free strains are S= 1000ppm = 0.1%Stroke : u = δL = S . L
Example : L = 100mm, S = 1000ppm => u = δL = 0.1mm = 100µm
L δL
E
04/06/2010 1 Day Piezo Training 2010 7
Active stress of active materials
Blocked Stress of active materialsStress = force par unit of surface : T = - F / A
Compression is positive stress ; Traction is negative stressUnits : MPa = N /mm2
Typical active blocked stresses are T= 20MPa = 20 N /mm2
Ex. A = 1cm² ; T = 20MPa => F = 2000N = 2kN
Stress from electromagnets T = B²/2µo = 0.4 MPa with B=1T
A- F F
04/06/2010 1 Day Piezo Training 2010 8
Active materials properties
Active materials offer small strains (ie small displacement) & high forces density compared with electromagnetic actuators
Field E Field / H Field
Strain Stress Young’s modulus
Coupling factor
Relative permitivity / permeability
Curie temp.
Density
E (MV/m) H (MA/m)
(ppm) (MPa) (Gpa) (%) - (°C) (kg/m3)
Piezo-electrics Bulk
PZT - 7 E +- 0.5 +- 70 +- 5 72 67 425 350 7.7
Bulk PZT - 4
E + - 0.5 +- 150 +- 10 66 70 1300 325 7.6
Bulk PZT - 5
E +- 0.5 +- 300 +- 15 48 75 3400 195 7.5
MLA E +- 2.6 + 1 250 + 40 30 70 2100 180 8.0 Magnetostrictives
Terfenol-D H + 0.16 + 1 800 + 50 25 70 4 380 9.1 Mag. Shape Mem.
NiMnGa H + 0.5 + 60 000 (6%)
+ 2
04/06/2010 1 Day Piezo Training 2010 9
Piezoelectric effects
Piezoelectric material = non centro-symmetric crystal belowthe Curie temperature
Direct effect: sensing Inverse effect: actuation
Courtesy of APC
D ~ d T S ~ d Ed: piezo coefficient E: Electrical fieldS: Strain; D: Electric displacementT: Stress
04/06/2010 1 Day Piezo Training 2010 10
Pyroelectricity & Electrostriction
Pyroelectric material = piezoelectric + polar material=> ∆P = p ∆T
P: Polarisation; T: Temperature; p: pyroelectric coefficient
Pure electrostrictive material = non piezoelectric material=> S = M E2 = Q P2
M & Q: cofficients of electrostriction; S: strain; E: electric field
Pyroelectricity & electrostriction are disturbing effects on piezoelectric response
Actually, piezo strain combines all effects in a more or lessextend :
S = d E + M E2 + α ∆T
04/06/2010 1 Day Piezo Training 2010 11
Ferroelectric materials
PZT “lead Titanium –Zirconate”:Ferroelectric material under the Curie temperature.A poling process gives the material its remanent polarization. During the
poling process, the material is subjected to a high electric field at the Curie temperature.
If the material is subjected to a temperature that is greater than its Curie point, it’s no longer piezoelectric but it can be repoled again in some conditions.
Std 80°C but 150°C on request
04/06/2010 1 Day Piezo Training 2010 12
Ferroelectric materials
Origin of poling in ferroelectric materials :Crystal structure, + & - charge centres may not coincide, even if
E = 0.Ferroelectric = material whose direction of poling can be reversed
by an electric field.
Characteristic of a ferroelectric material : high relative permittivity
D E P ED electric displacementP polarization
relative permittivity
= + =ε ε ε
ε
0 0.: ,: ,:
04/06/2010 1 Day Piezo Training 2010 13
Interpretation of poling in PZT crystal structures
Perovskite structure in PZTDifferent shapes of the crystal structure
Courtesy of Tokin
Sub solidus phase diagram of PZT Ceramics(B. Noheda & al)
04/06/2010 1 Day Piezo Training 2010 14
Intrinsic / Extrinsic piezoelectricity
Intrinsic piezoelectric effect : strain of the crystal lattice
Extrinsic piezoelectric effect : domain reorientation
=> Hysteresis
04/06/2010 1 Day Piezo Training 2010 15
Hysteresis butterfly cycle
Courtesy of Tokin Repoling process in the domains
04/06/2010 1 Day Piezo Training 2010 16
Piezo ceramic vs Single Crystal
PZT Piezo ceramicsIndustrial materials produced by sintering of powderCompatible with multilayer technique to get low voltagesLinear strain response
Single crystalsNew material obtained by crystal growthLarge strains with large E-fieldNot compatible with multilayer so need large voltagesNon linear (electrostrictivecontribution)
04/06/2010 1 Day Piezo Training 2010 17
Piezo ceramics : Manufacturing process of bulk materials
Mixing oxyde powders Zr02, Ti02, PbO, with a binderSintering at high temperature (1200°C),Cutting & Grinding at the correct size,External electrodes deposition (Screen printing, PVD, …)Poling operation :
room temp. / 2 kV/mm for soft - type,120°C, 5 kV/mm, in oil for hard type.
04/06/2010 1 Day Piezo Training 2010 18
General constitutive law of piezoelectric body
No electrostriction & pyroelectric effectsChoosing T and E as independent variables
S s T d E
D d T E
En n
m m mnT
n
α αβ β α
β β ε
= +
= +α β, , . . . ,
, , ,==
1 61 2 3m n
sE : Compliances at constant fieldd : Piezoelectric strains per unit of fieldeT : Permittivity at constant stress
S : Strain T : Stress D : Induction E : Field
1
2
3
P4
6
5
04/06/2010 1 Day Piezo Training 2010 19
Constitutive law of PZT ceramicsPTZ ceramic : 6 mm class
SSSSSS
DDD
s s s d
s s s d
s s s d
s d
s d
s
d
d
E E E
E E E
E E E
E
E
E
T
1
2
3
4
5
6
1
2
3
11 12 13 31
12 11 13 31
13 13 33 33
44 15
44 15
66
15 11
15
0 0 0 0 0
0 0 0 0 0
0 0 0 0 0
0 0 0 0 0 0 0
0 0 0 0 0 0 0
0 0 0 0 0 0 0 0
0 0 0 0 0 0 0
0 0 0 0
⎡
⎣
⎢⎢⎢⎢⎢⎢⎢⎢⎢⎢⎢⎢⎢⎢
⎤
⎦
⎥⎥⎥⎥⎥⎥⎥⎥⎥⎥⎥⎥⎥⎥
+
ε
0 0 0
0 0 0 0 011
31 31 33 33
1
2
3
4
5
6
1
2
3ε
ε
T
Td d d
TTTTTT
EEE
⎡
⎣
⎢⎢⎢⎢⎢⎢⎢⎢⎢⎢⎢⎢⎢⎢⎢⎢
⎤
⎦
⎥⎥⎥⎥⎥⎥⎥⎥⎥⎥⎥⎥⎥⎥⎥⎥
⎡
⎣
⎢⎢⎢⎢⎢⎢⎢⎢⎢⎢⎢⎢⎢⎢
⎤
⎦
⎥⎥⎥⎥⎥⎥⎥⎥⎥⎥⎥⎥⎥⎥
.=
04/06/2010 1 Day Piezo Training 2010 20
Electromechanical coupling effect
Materials show 3 coupled deformation due to non-zero coefficients d33 d31 d15
1
2
3
P4
6
5
In static : S3=d33 E3
31 : Transverse mode 15 : Shear mode33 : Longitudinal modeIn static : S1=d31 E3 In static : S5=d15 E1
04/06/2010 1 Day Piezo Training 2010 21
Electromechanical coupling effect
Materials properties are characterised by intrinsic coupling coefficients
Longitudinal coupling factor k33
Transverse coupling factor k31
Shear coupling factor k15
k332 = d33
2 / s33E ε33
T
k312 = d31
2 / s11E ε33
T
k152 = d15
2 / s44E ε11
T
04/06/2010 1 Day Piezo Training 2010 22
Electromechanical coupling effect
Meaning of the coupling coefficient: Coupled energies in a usual magnetic transformer
U12 = Mutual Energy U1 = Energy in the Primary U2 = Energy in the Secondary
Transformer coupling factor
In an electromechanical deviceUem = Mutual Electromecanical Energy Ue = Electrical EnergyUm = Mecanical Energy
kem2 = Uem
2 / Ue .Um
k2 = U122 / U1 .U2
04/06/2010 1 Day Piezo Training 2010 23
Physical properties of piezo materials
Courtesy of Nava Seter (ABC of piezoelectricity, Interlaken conference, feb. 2002)
04/06/2010 1 Day Piezo Training 2010 24
Constitutive law of PZT ceramics
Simplification for a length - expansion mode (33-mode)
T T T T T S S SE E D D
1 2 4 5 6 4 5 6
1 2 1 2
0 00 0
= = = = = = = == = = =
;;
S S s T d E
S s T d E
D d T E
E
E
T
1 2 13 3 31 3
3 33 3 33 3
3 33 3 33 3
= = +
= +
= +
.
.
. ε
3
04/06/2010 1 Day Piezo Training 2010 25
Laws of Piezo actuators
Simplification for a length - expansion bar (33-mode)A : active area L : active length
∆u u u L SF A TV L EQ A D
= − == −==
2 1 3
3
3
3
..
..
A
L
+ V0 0
U 2U 1
{k A s L
N d k
C A L
E E
E
T T
=
=
=
/
.
. /
33
33
33ε
VCFkNQ
VkNF
ku
TE
EE
..
..1
+−=
+−=∆
04/06/2010 1 Day Piezo Training 2010 26
Laws of Piezo actuatorsSimplification for a length - expansion bar (33-mode)
A
L
+ V0 0
U 2U 1
{
∆uk
FNk
V
QNk
F C V
E E
T
= − +
= − +
1. .
. .
S S s T d E
S s T d E
D d T E
E
E
T
1 2 1 3 3 3 1 3
3 3 3 3 3 3 3
3 3 3 3 3 3 3
= = +
= +
= +
.
.
. ε
k332 = d33
2 / s33E ε33
T = N2/kE.CT
04/06/2010 1 Day Piezo Training 2010 27
Laws of Piezo actuators
kN
C kC C k
eff T E
s Teff
22
21
=
= −( )
VCuNQVNukF
S
E
...
+∆=
+∆−=F
NVk
u
NV
Generalisation
04/06/2010 1 Day Piezo Training 2010 28
Laws of Piezo actuators
Generalisation – Characteristic curve of a piezo actuator
NV = Max Force without displacement @ V
If V = Vmax = 150 V => Max Force = Blocked Force (Fb)
∆ u max = NV/K = Max Displacement @ V
If V = Vmax = 150 V => ∆ u max is the max stroke
∆u = (NV-F)/K∆ u max
Fb
V=50V
V=150V
Slope 1/K = elasticity
Stroke
Force
04/06/2010 1 Day Piezo Training 2010 29
Additional effects in static applications
Hysteresis:
04/06/2010 1 Day Piezo Training 2010 30
Additional effects in static applications
Creep effect:
Actuator's displacement (µm) - Record of the creep effectusing a capacitive displacement sensor
0,00
20,00
40,00
60,00
80,00
100,00
120,00
140,00
0 200 400 600 800 1000 1200 1400 1600
Time (s)
Disp
lace
men
t (µm
)
04/06/2010 1 Day Piezo Training 2010 31
Additional effects in static applications
Displacement with load: 2 casesStiffnessGravity
May be accounted in equivalent circuits
(b) (a) (c)
04/06/2010 1 Day Piezo Training 2010 32
Application parameters that influence the piezo actuators
Spring Gravity
Force
Displacement
Load characteristics
Spring stiffness
Working point
Displacement
Force
No-load charac. curve
Shifted curve
04/06/2010 1 Day Piezo Training 2010 33
Additional effects in static applications
Displacement with load: 2 cases
04/06/2010 1 Day Piezo Training 2010 34
Laws of Piezo actuators - Equivalent circuit
Equivalent electromechanical circuit : Dynamic aspects
∆v v v j uI j Q
c k E
= − ==
=
2 1
1
ω∆ω
/
V NV F
1 : N
Cs
I ∆vc
Fj c
v N V
I N v j C Vs
= − +
= +
1ω
ω
∆
∆
Electrical Branch Motional Branch
Motional capacitance = 1/ Stiffness
Current
speed
CS = Blocked capacitance
04/06/2010 1 Day Piezo Training 2010 35
Electro-mechanical analogy
FForcePotentialV
V = du/dt = jω.uSpeedCurrentI = dQ/dt = jω.Q
uDisplacementElectrical chargeQ
rmDampingResistanceR
MMassInductanceL
e = 1/k (k=stiffness)ElasticityCapacitanceC
SymbolMechanicsElectricSymbol
04/06/2010 1 Day Piezo Training 2010 36
Equivalent circuits & related data
Same equivalent circuit but …: Boundaries conditions
Free-free configuration: The same mass each side of the piezo actuator: The stroke is divided by 2 and the resonant frequency is higher.
Blocked-free configuration: Blocked on the back side of the actuator the stroke in the front is the full stroke & the frequency is lower than the free free configuration.
Blocked-Blocked configuration: the piezo actuator is rigidly fixed on each side. The actuator generates force when voltage is applied.
04/06/2010 1 Day Piezo Training 2010 37
Losses in equivalent circuit
Dielectric LossesDielectric loss angle : tg d => Ro
Mechanical lossesMechanical quality factor : Qm => rm
Ro V NV F
1: N
Cs
I ∆vrm c
04/06/2010 1 Day Piezo Training 2010 38
Masses in equivalent circuit
Masses effectIn blocked-free condition,
Blocked side : v1 = 0 Free side, loaded with a mass M : F = j.ω.M.v2
In free-free conditions, with M1 and M2
Equivalent mass M = M1 . M2 / (M1 + M2)
Ro V NV F
1: N
Cs
I ∆vrm cM
04/06/2010 1 Day Piezo Training 2010 39
Transfer functions
Vibration speed & displacement vs voltage
)1(//
)1(//
)/1(/)/1(.
2
2
cMcrjcNVu
cMcrjcNjVv
MjrcjNVvMjrcjvNV
m
m
m
m
ωω
ωωω
ωωωω
−+=∆
−+=∆
++=∆++∆=
Ro V NV F
1 : N
Cs
I ∆vrm cM
04/06/2010 1 Day Piezo Training 2010 40
Transfer functions
Vibration speed & displacement vs voltageMechanical resonance frequency & Mode quality factor :
mr
E
mr
E
r rk
crQ
Mk
cM ωωω ====
11
Ro V NV F
1 : N
Cs
I ∆vrm cM
))/(/1(// 2rrQjcNVu ωωωω −+=∆
))/(/1(// 2rrQjcNjVv ωωωωω −+=∆
04/06/2010 1 Day Piezo Training 2010 41
Transfer functions
Vibration speed & displacement vs voltageAt low frequency : Free displacement
At resonance : Amplified displacements
At high frequency : Blocked force
Ro V NV F
1 : N
Cs
I ∆vrm cM
cNVu =∆ / cNjVv ω=∆ /
cNQVv rω=∆ /0)/.(/ =∆==∆ ωVuQQcNVu
NVF =/
04/06/2010 1 Day Piezo Training 2010 42
Equivalent circuit & associated data
Example APA200M+Mass M=40gr (Blocked-Free)Low Frequency f << fr
No opposing force from the Mass‘Free’ displacement : uLF = N/k. V
Resonance f = frfr = 1/2pi (k/M)0.5
Amplification by Qm : Mec. Quality factorDisplacement : uRes = Qm. N/k. V = Qm. uLF
3dB Bandwidth : df / Qm = fr /df
High Frequency f >> frMass opposing force = ‘Blocked’ force : FHF= N.V
04/06/2010 1 Day Piezo Training 2010 43
Equivalent circuit & associated data
Example APA200M+Mass=40gr (Blocked Free)Low Frequency f << fr
‘Free’ disp. : uLF = N/k.V => uLF/V= N/k u=230µm@V=150V => uLF/V= 1.3µm/V
Resonance f = frk=0.32N/µm ; M=0.04kg ; Qm = 10 fr = 1/2pi (k/M)0.5 => fr = 0.4kHzDispl. : uRes = Qm. uLF => uRes/V= 13µm/V 3dB Bandwidth : df = fr / Qm => df = 40 Hz
High Frequency f >> fr‘Blocked’ force : FHF= N.V => FHF/ V = NF=73N@150V => FHF/ V = N = 0.43N/V
04/06/2010 1 Day Piezo Training 2010 44
Equivalent circuit & associated data
APA200M+Mass=40gr (B.F.) / displacement per volt vs freq.
Controllable displacement :
Displ. Amplitude & Phase = Constant if :
f < fr/3
fr
Displacement generation
uLF/V = N/k0,00
2,00
4,00
6,00
8,00
10,00
12,00
14,00
16,00
0,000 0,100 0,200 0,300 0,400 0,500 0,600 0,700 0,800 0,900Frequency [kHz]
[µm/V]
-200
-180
-160
-140
-120
-100
-80
-60
-40
-20
0
Mod(u) [µm/V]Phase(u) [°]
[°]
© Cedrat Technologies - COMPACT v4.33
04/06/2010 1 Day Piezo Training 2010 45
0,00
2,00
4,00
6,00
8,00
10,00
12,00
14,00
16,00
0,000 0,100 0,200 0,300 0,400 0,500 0,600 0,700 0,800 0,900Frequency [kHz]
[µm/V]
-200
-180
-160
-140
-120
-100
-80
-60
-40
-20
0
Mod(u) [µm/V]Phase(u) [°]
[°]
© Cedrat Technologies - COMPACT v4.33
Equivalent circuit & associated data
APA200M+Mass=40gr (B.F.) / displacement per volt vs freq.
fr
Qm
uLF/V = N/k
ures/V = Qm. N/k
Vibrations : Non Controllable displacements(Phase varies)
Amplitudes are amplified by Qm
Vibration generation
04/06/2010 1 Day Piezo Training 2010 46
0,0
5,0
10,0
15,0
20,0
25,0
30,0
35,0
40,0
0,0000 0,1000 0,2000 0,3000 0,4000 0,5000 0,6000 0,7000 0,8000 0,9000-180,00
-160,00
-140,00
-120,00
-100,00
-80,00
-60,00
-40,00
-20,00
0,00
Mod(v1) [mm/s/V]Phase(v) [°]
Frequency [kHz]
Mod(v) [mm/s/V]
© Cedrat Technologies - COMPACT v4.33
Phase [°]
Equivalent circuit & associated data
APA200M+Mass=40gr (B.F.) / speed per volt vs freq.
Vibrations : Controllable Speed Amplitude
3dB Bandwidth : df = fr / Qm
fr
Vibration generation
df = fr / Qm
04/06/2010 1 Day Piezo Training 2010 47
0,0
0,5
1,0
1,5
2,0
2,5
3,0
3,5
4,0
4,5
5,0
0,0000 0,1000 0,2000 0,3000 0,4000 0,5000 0,6000 0,7000 0,8000 0,9000Frequency [kHz]
Forc
e [N
/V] Mod(Fa) [N/V]
© Cedrat Technologies - COMPACT v4.33
Equivalent circuit & associated data
APA200M+Mass=40gr (B.F.) / Force per volt vs freq.
Controllable Dynamic Forces
Force Amplitude & Phase = Constantif
f >1.5 fr
fr
Dynamic Force generation
FHF/V = N = force factor
04/06/2010 1 Day Piezo Training 2010 48
Admittance from equivalent circuit
Transferring motion branch in the electrical branchMotional capacitanceMotional resistanceMotional inductance
Ro V
Cs
I im Rm Cm Lm
2
2
2
/
/
.
NML
NrR
NcC
m
mm
m
=
=
=
04/06/2010 1 Day Piezo Training 2010 49
0,00E+00
2,00E-03
4,00E-03
6,00E-03
8,00E-03
1,00E-02
1,20E-02
1,40E-02
1,60E-02
1,80E-02
2,00E-02
0,0000 0,1000 0,2000 0,3000 0,4000 0,5000 0,6000 0,7000 0,8000 0,9000Frequency [kHz]
[S]
-20
0
20
40
60
80
100
Mod(Y) [S]Phase(Y) [°]
[°]
© Cedrat Technologies - COMPACT v4.33
Equivalent circuit & associated data
APA200M+Mass=40gr (B.F.) / Admittance vs frequency
fr fa
Free capa. : CT
Blocked capa. : CS
Motion Cap : CmCm=CT-CS
Effective couplingkeff2 = 1 - fr2/fa2
=1-CS/CT
CS
CT
04/06/2010 1 Day Piezo Training 2010 50
Equivalent circuits & related data
Effective coupling coefficient : keff
2 = 1 - fr2/fa2 = Cm / (Cm+Cs)
Electrical Resonance frequency : fr2 = (1/4π2) k/m = (1/4π2) / CmLm
Electrical Antiresonance frequency : fa2 = (1/4π2) [(Cs+Cm)/LmCsCm]
Mechanical quality factor :Qm = 1/(2πfrCmRm)
04/06/2010 1 Day Piezo Training 2010 51
Equivalent circuit & associated data
3 Frequency regionsLow frequency f < fr/3
Positioning applicationsFast actuation: injection valves, shutters …
Resonance f = fr Sonic and ultrasonic transducersAcoustic generators …
High frequency f> frStructure exciters in health monitoringProof mass dampers …
04/06/2010 1 Day Piezo Training 2010 52
Equivalent circuit & associated data
Displacement Transient response for a step voltageOvershot effects & Stabilisation time
=> Dynamic effects occur even on static applications=> High fr and low Q is better for static applications
Step response
0
1
2
0 1 2 3 4 5 6 7 8t / T
u / u
0
High QLow Q
T = 1 / fr
Tmin (open loop) = T/4
Tmin (Closed loop) = T/3
1/4
04/06/2010 1 Day Piezo Training 2010 53
Additional effects in dynamic applications
Multiple vibration modesMulti modes electromechanical model:
VoltageSpeed
04/06/2010 1 Day Piezo Training 2010 54
Electromechanical circuits : summary
Lumped representation,Electromechanical transduction means a «strong»coupling effect,Basic representation, widely used in measurements, semi active control, switching electronic design,A common basis for piezoactive actuators description.
04/06/2010 1 Day Piezo Training 2010 55
Conclusion
Piezoelectricity : strong electromechanical coupling effect,The materials are characterised through 3 types of constants (s,d,ε),Wide use of the electromechanical analogy,An electrical scheme can be derived for simple cases and measured.
04/06/2010 1 Day Piezo Training 2010 56
Piezoelectric Multi-layer Ceramics
04/06/2010 1 Day Piezo Training 2010 57
Introduction
Basic architectureProcessInternal & external electrodesBehaviour, failure modesFuture of MLA
04/06/2010 1 Day Piezo Training 2010 58
Bulk Piezoelectric Stack
StructureAssembled stack made of thick piezo plates & external electrodes electrically connected in parallel with alternative poling and electrodes
P
P
P
P
+ -
E
E
E
E
04/06/2010 1 Day Piezo Training 2010 59
Piezoelectric multilayer actuators
StructureMonolithic Stack made of thin piezo layers & internal electrode electrically connected in parallel with alternative poling and electrodes & external electrodes
P E
P E SS
04/06/2010 1 Day Piezo Training 2010 60
Piezoelectric Multilayer actuator : technological aspects
Green tape (mixture of oxydes (Zr02, Ti02, Pb0) with an organic binder),Indexing and screen printing of internal electrodes,Laminating operation (tape, stacking),Sintering operation,Cutting, grinding at the correct size,External electrodes deposition,Insulation,Poling operation.
04/06/2010 1 Day Piezo Training 2010 61
Bulk Piezo Ceramic: Manufacturing process
04/06/2010 1 Day Piezo Training 2010 62
Piezo Multilayer actuator : Manufacturing process
Courtesy of Ceramtec
04/06/2010 1 Day Piezo Training 2010 63
Piezo Multilayer components : technological aspects
Technical difficulties :compatibility between the internal electrodes material and the sintering operation,shrinking during sintering (15 - 20 %).
850°C 1150°C 1250°C
Nickel, Copper Palladium Platinium
04/06/2010 1 Day Piezo Training 2010 64
Piezoelectric multilayer actuators : internal & external electrodes
Internal and external electrodes influence the materials properties ; example of electrodes configurations :
04/06/2010 1 Day Piezo Training 2010 65
Piezoelectric multilayer actuators : internal & external electrodes
Fully open internal electrodes :indexing operation, thermal mismatch, capability to deal with several sizes are easy,external insulation (esp. on the external electrodes) is tricky,subjected to ion migration,patented by Tokin (J).
04/06/2010 1 Day Piezo Training 2010 66
Piezoelectric multilayer actuators : internal & external electrodes
Semi-open internal electrodes :thermal mismatch is medium,indexing operation is medium,need for an insulating coating,subjected to ion migration,
04/06/2010 1 Day Piezo Training 2010 67
Piezoelectric multilayer actuators : internal & external electrodes
Buried internal electrodesthermal mismatch & stress relieving are tricky,no needs for external insulation coating,current density is limited,non poled ceramic tends to clamp the component.
04/06/2010 1 Day Piezo Training 2010 68
Piezoelectric multilayer actuators : internal & external electrodes
Special design internal electrodes :claimed advantage : stress relieving during the sintering operation is easier,performances depend on the clamped region,1st special geometry patented by Siemens (D).
04/06/2010 1 Day Piezo Training 2010 69
Piezoelectric multilayer components : technologies for external electrodes
Sputtered Ag-Pd external electrodes : bad solderability,
Ni-Au electro-deposited + Pb-Ag solder :better behaviour, subjected to fatigue effects,
Ni-Au electro-deposited + brazed mesh :good fatigue behaviour, patented by Ceramtec (D), subjected to failures with thermal shocks.
04/06/2010 1 Day Piezo Training 2010 70
Coating technologies
Required dielectric strength : 80 kV/mm,Stability of the electrical insulation with temperature, humidity, …Compatibility with aggressive media,Relative independence of the elastic behaviour with temperature, ageing, …Easiness of application (viscosity, ..).
04/06/2010 1 Day Piezo Training 2010 71
Functional performances
Standard materials (PZT5H) gives 1000 - 1300 ppm @ 1.5 - 2 kV/mm,On-going development of PZT5A materials :
high Curie Temp. (300 °C),1300 ppm @ 1.5 - 2 kV/mm,not necessarily commercially available.
Hard - type material (PZT4) may give 2000 ppm when driven at the mechanical resonance :
subjected to high cost of the internal electrodes.
04/06/2010 1 Day Piezo Training 2010 72
Functional performances
Static strain levelDielectric lossesCTEDriftHysteresis
04/06/2010 1 Day Piezo Training 2010 73
FMECA analysis
Process errors are expected to be discovered at the poling operation or through an over- voltage test,
Electrical breakdown is the most current problem :loss of insulation (failure in the coating due to humidity or excessive temperature),excessive stresses, crack propagation,Ag+ ion migration under humidity combined with high DC field.
Mechanical failure is often meet in dynamic conditionsPiezo ceramic are fragile in tensional forcesSee Prestressed-actuator section
04/06/2010 1 Day Piezo Training 2010 74
MLA tested in APA : Lifetime tests
1010 cycles are achieved on a APA200M-NM ! Prestressed Actuator
Test conditions : 0-150 V @ 625 Hz, continuous
101 cycles 109 cycles
04/06/2010 1 Day Piezo Training 2010 75
MLA tested in APA : Lifetime tests
Electrical admittance evolution vs number of cycles.
Cyclage APA200M
0
0,1
0,2
0,3
0,4
0,5
0,6
0,7
0,8
3300 3400 3500 3600 3700 3800 3900f( Hz)
Admittance (S)
-80
-60
-40
-20
0
20
40
60
80
100Phase(°)
Mag 0 [S]Mag 1e6 [S]Mag 1e7 [S]Mag 1e8 [S]Mag 1e9 [S]Phase 0 [°]Phase 1e6 [°]Phase 1e7 [°]Phase 1e8 [°]Phase 1e9 [°]
04/06/2010 1 Day Piezo Training 2010 76
MLA tested in APA : Lifetime tests
Fatigue effects of the external electrodes after 4 109 cycles
04/06/2010 1 Day Piezo Training 2010 77
Leakage current test under high humidity
Electrical DC field under humidity ⇒Ion migration ⇒Increase of leakage current ⇒Increase of temperature ⇒Electrical breakdown
Leakage current test
-1.40E-02
-1.20E-02
-1.00E-02
-8.00E-03
-6.00E-03
-4.00E-03
-2.00E-03
0.00E+00
2.00E-03
0 200 400 600 800 1000 1200 1400
Time (hours)
Curr
ent (
A)
0.00E+00
4.00E+01
8.00E+01
1.20E+02
Rela
tive
hum
idity
(%)
APA50S_01011APA50S_00060APA50S_00059PCT1PCT 2T1T2T3APA150M_01003TCMELRel. Humidity (%)
Failure
Failure
04/06/2010 1 Day Piezo Training 2010 78
Reliability aspects
Arc over is the most important source of failure,Expertise of failed components.
High porosity Void probably after the arc over ?Acoustic tomography
Optical microscope view
04/06/2010 1 Day Piezo Training 2010 79
Future of MLAs
Most advanced factories produce 100,000 units to 1,000,000 units/ year.Demonstrating the reliability in a given applications :
Arrhenius laws, Hass-halt tests,
Correct functional behaviour with a low sintering temperature,Use of the internal electrodes materials as dopants for the PZT material.
04/06/2010 1 Day Piezo Training 2010 80
Piezoactive actuators : introduction
Material properties,Advantages and drawbacks of piezoactive actuators,Conventional mechanical amplifiers,
internally leveraged actuatorsexternally leveraged actuators
Amplified Piezo Actuators = Innovative solutions,Design methodology & Performances,Mechanisms = multi axis actuationConclusion.
04/06/2010 1 Day Piezo Training 2010 81
Active materials : properties
Field E Field /H Field
Strain Stress Young’smodulus
Couplingfactor
Relativepermitivity /permeability
Curietemp.
Density
E (MV/m)H (MA/m)
(%) (MPa) (Gpa) (%) - (°C) (kg/m3)
Piezoelectrics
PZT - 7 E +- 0.5 +- 0.007 +- 5 72 67 425 350 7.7
PZT - 4 E + - 0.5 +- 0.015 +- 10 66 70 1300 325 7.6
PZT - 5 E +- 0.5 +- 0.030 +- 15 48 75 3400 195 7.5
CMA E +- 2.6 + 0.125 + 40 30 70 2100 180 8.0
Magnetostrictives
Terfenol-D H + 0.16 + 0.18 + 50 25 70 4 380 9.1
04/06/2010 1 Day Piezo Training 2010 82
Active properties
MATERIALS Controlfield
E electricH magnetic
Max S-cstdielectric /magneticenergydensity
(kJ/m3)
Max field-cst elastic
energydensity
(kJ/m3)
OptimalMechanical
quality factor
(Qm)opt
Maxdissipated
energydensity
on (Qm)opt
(kJ/m3)
Max dissipatedenergy density
on Qm =2
(kJ/m3)
MASSIVE PIEZOELECTRICSPZT - 8 E 0.6 16.9 6.1 2.8 0.9PZT - 7 E 0.3 17.4 9.1 1.9 0.4PZT - 4 E 0.7 19.0 5.2 3.7 1.4PZT - 5 E 1.6 26.0 3.5 7.4 4.2
MULTILAYERED PIEZOELECTRICSSoft type E 8.0 26.7 1.9 14.3 13.3Hard type E 12.6 25.0 1.9 13.3 12.5
MAGNETOSTRICTIVESTERFENOL-D H 8.2 50.0 2.5 19.8 15.8
04/06/2010 1 Day Piezo Training 2010 83
New European classification : example of material
Type 100 Type 200 Type 300 Type 600
Property Symbol
Unit Hard PZT Soft PZT Very hard PZT Very soft PZT
Free relativepermittivity
εT33
1100 - 1600 1600 - 2500 800 - 1100 2500 – 4000
CurieTemperature
Tc °C 300 300 250 180
Mechanicalquality factor
Qm 300 100 800 100
Piezoelectricchargecoefficient
d33 PC/N 300 400 250 600
Example ofmaterial
Ceramtec SP4Ferroperm PZ26Matroc PZT4DChannel 5400
Ceramtec SP5Ferroperm PZ27Matroc PZT5AChannel 5500
Ceramtec SP8Ferroperm PZ28Matroc PZT8Channel 5804
Ceramtec SP51Ferroperm PZ29Matroc PZT5HChannel 5700
04/06/2010 1 Day Piezo Training 2010 84
Piezoelectric actuators and mechanisms
04/06/2010 1 Day Piezo Training 2010 85
Advantages & drawbacks of piezoelectric actuators
Fast responseUnlimited positioning resolutionLarge forceNon-magnetic operation & no magnetic field generated
Limited displacementsSubjected to fatigue effect (depends on the design)Temperature dependant (Curie temperature)
04/06/2010 1 Day Piezo Training 2010 86
Piezoelectric Multi-Layer Actuators (MLA)
History of piezo ceramics1880 : Quartz (P.Curie)1922 : Langevin Transducers1960 : PZT ceramics
∆L/L = 0,3mm/m @ ∆V= 2000V
1990 : MLA components∆L/L = 1,2mm/m @ ∆V=200V
Structure of a MLAPiezo layers (PbZrTi)Internal Electrodes (Pt or AgPd)External Electrodes Insulation (Coating or ceramic)
The naked MLA ceramic bar is fragile to tensile force...
04/06/2010 1 Day Piezo Training 2010 87
Internally leveraged Actuators (stack)
Direct Piezo ActuatorsTwo different prestress
serial parallel
Belleville washers
DPA30
Piezo stack
… that is why we pre-stress it to increase its life time
04/06/2010 1 Day Piezo Training 2010 88
Preload / Prestress of Piezo Ceramic
Stress – Strain DiagramThanks to an optimum
static Preload,the strain is symmetricin traction & in compressionThe dynamic strain & stress range issymmetric and muchmore increased thanwithout preload
S = Strain
F/A = StressPiezo Ceramic is fragile in tensile stress
Elastic limit in traction
Elastic limit in compression
Optimum level of static preload / compression pre-stressing force
Dynamic range without preload
Dynamic range with preload
04/06/2010 1 Day Piezo Training 2010 89
Direct piezo actuators can be pre- stressed through an external frame.
The design of the parallel spring is dependant on the applied prestress.
Stress analysis of the pre-stress frame of the
PPA (I-DEAS computation
of half the frame)
Internally leveraged Actuators (stack)
PPA60L
04/06/2010 1 Day Piezo Training 2010 90
Pre-load effect - short & open circuit
04/06/2010 1 Day Piezo Training 2010 91
Internally Leveraged Actuators (bender)
Courtesy of Midé (ACX) & CeraNova
Quick Pack 10ni
04/06/2010 1 Day Piezo Training 2010 92
Internally Leveraged Actuators (bender)
Courtesy of PI
04/06/2010 1 Day Piezo Training 2010 93
Internally Leveraged Actuators (bender)
Ring Bender CMB-R - Courtesy of NOLIAC
04/06/2010 1 Day Piezo Training 2010 94
Internally Leveraged Actuators (unimorph)
Courtesy of Aura Ceramics Inc.
04/06/2010 1 Day Piezo Training 2010 95
Internally Leveraged Actuators (unimorph)
Courtesy of Face international
Thunder TH 8-R
04/06/2010 1 Day Piezo Training 2010 96
Internally Leveraged Actuators (building block)
Courtesy of Michigan University & MSI
04/06/2010 1 Day Piezo Training 2010 97
Externally leveraged actuators (hydraulic amplification)
04/06/2010 1 Day Piezo Training 2010 98
Use of flexural hinges and pivots
Mechanical Efficiency η = (FActuator*uActuator) / (FMLA*uMLA) = 10%
MLA piezo ceramic
Externally leveraged actuators (lever arm)
Hertzian pivots
flexure pivots
04/06/2010 1 Day Piezo Training 2010 99
Externally leveraged actuators (flextensional)
04/06/2010 1 Day Piezo Training 2010 100
Externally leveraged actuators (flextensional & others)
04/06/2010 1 Day Piezo Training 2010 101
Amplified piezoelectric actuators
magnification of the MLA displacements using an elastic amplifier,
reduction of the blocked force,
optimisation of the overall efficiency
Includes a high prestress to get good dynamic properties
04/06/2010 1 Day Piezo Training 2010 102
Amplified piezoactive actuators
Use of the flextensional principle (uniform distribution of flexure pivots along the shell),The elastic amplifier is used to prestress the active material.
04/06/2010 1 Day Piezo Training 2010 103
Amplified Piezo Actuators
Finite element deformations (ATILA software)
04/06/2010 1 Day Piezo Training 2010 104
Amplified piezo actuatorsRange of APAs
04/06/2010 1 Day Piezo Training 2010 105
Amplified piezoactive actuators
04/06/2010 1 Day Piezo Training 2010 106
Amplified piezoactive actuators
Smallest APAs to largest APAs
APA 40µXS , APA35XS, APA500XXL
04/06/2010 1 Day Piezo Training 2010 107
APA static properties
APA DeformationsAPA strain : Sa = ua / hPiezo strain : Sp = up / L
h
L
ua
up/2 up/2
04/06/2010 1 Day Piezo Training 2010 108
Actuators type APA APA APA120ML 400M 900M
Actuator dataFree displacement µm u a 130 400 916
Max Blocked force N F a 1 400 40 16Stiffness N/µm 10,8 0,1 0,017Actuator Height cm h 4,5 1,4 1,1
Actuator free strain % S a 0,29 2,9 8,3
Active material dataLength cm 6 4 4Section cm2 1 0,25 0,25No-load strain ppm S p 1000 1000 1000Blocked stress MPa 40 40 40No-load displacement µm u p 60 40 40
Blocked force N F p 4000 1000 1000
Amplifcation analysisDisplac. amplification factor A u 2,2 10,0 22,9
Strain amplification factor A s 2,9 28,6 83,3Force disamplification factor 2,9 25,0 63,5Actuator mechanical efficiency % η 76% 40% 36%
APA static properties
APA DeformationsAPA strain :
Sa = ua / h
Piezo strain :Sp = up / Lp
04/06/2010 1 Day Piezo Training 2010 109
Actuators type APA APA APA120ML 400M 900M
Actuator dataFree displacement µm u a 130 400 916
Max Blocked force N F a 1 400 40 16Stiffness N/µm 10,8 0,1 0,017Actuator Height cm h 4,5 1,4 1,1
Actuator free strain % S a 0,29 2,9 8,3
Active material dataLength cm 6 4 4Section cm2 1 0,25 0,25No-load strain ppm S p 1000 1000 1000Blocked stress MPa 40 40 40No-load displacement µm u p 60 40 40
Blocked force N F p 4000 1000 1000
Amplifcation analysisDisplac. amplification factor A u 2,2 10,0 22,9
Strain amplification factor A s 2,9 28,6 83,3Force disamplification factor 2,9 25,0 63,5Actuator mechanical efficiency % η 76% 40% 36%
APA static properties
APA amplificationDisplacement amplification:
Ad = ua / up
Strain amplification: As = Sa / Sp
04/06/2010 1 Day Piezo Training 2010 110
Actuators type APA APA APA120ML 400M 900M
Actuator dataFree displacement µm u a 130 400 916
Max Blocked force N F a 1 400 40 16Stiffness N/µm 10,8 0,1 0,017Actuator Height cm h 4,5 1,4 1,1
Actuator free strain % S a 0,29 2,9 8,3
Active material dataLength cm 6 4 4Section cm2 1 0,25 0,25No-load strain ppm S p 1000 1000 1000Blocked stress MPa 40 40 40No-load displacement µm u p 60 40 40
Blocked force N F p 4000 1000 1000
Amplifcation analysisDisplac. amplification factor A u 2,2 10,0 22,9
Strain amplification factor A s 2,9 28,6 83,3Force disamplification factor 2,9 25,0 63,5Actuator mechanical efficiency % η 76% 40% 36%
APA static properties
APA amplificationamplification efficiency:
η = (ua Fa) / (up Fp)
04/06/2010 1 Day Piezo Training 2010 111
APA dynamic properties
Prestress of Piezo Ceramic :Needed as it cannot bear tensile stress
APA stress budget considered at the design :prestress stress : static stresses from the prestress process.actuation stress : stresses produced in the shell when the ceramic is supplied. external force stress : stresses due to external vibrations or shock or applied forces.
⇒ No weak point in APAs :No hinges, elastic pivot...
04/06/2010 1 Day Piezo Training 2010 112
APA static properties
APA amplificationamplification efficiency:
η = (ua Fa) / (up Fp) Use of a genetic algorithm with the following objective :
free displacementefficiency η as high as possiblestresses < 0.75*Re.
0
5
10
15
20
100 110 120 130 140
Stroke (µm)
Stiff
ness
(N/µ
m)
Stress >=700MPaStress >=600MPaStress <600MPa56% Eff CurveAPA120ML
Example of a genetic run for the APA120ML
04/06/2010 1 Day Piezo Training 2010 113
Performances comparison
Actuator namesP844.60 PPA90L APA120ML APA230L APA500L APA500L-
SVAPA750XL-
SVActuatorActuator Mass gr 204 147 155 275 200 170 600Actuator Height cm 13.7 10.7 4.5 8.5 5.5 4.9 7.0Actuator Volume cm3 43 43 36 74 48 41 91
No-load free displacement µm 90 90 120 236 500 560 1150Stiffness N/µm 33 39 11.7 5.7 1.14 1.39 0.8Blocked force N 2 970 3 510 1 400 1 345 570 778 920Stored elastic energy J 0.134 0.158 0.084 0.159 0.143 0.218 0.529Output elastic energy mJ 33 39 21 40 36 54 132
Performances ratioFree deformation along active axe % 0.07 0.08 0.27 0.28 0.91 1.14 1.64Output Energy / actuator volume J/dm3 0.78 0.91 0.59 0.54 0.74 1.31 1.45Output Energy / actuator mass J/kg 0.16 0.27 0.14 0.14 0.18 0.32 0.22
Some CEDRAT products : Standard & customised
Best actuator in 1998 according to US specialists before Cedrat product launching
04/06/2010 1 Day Piezo Training 2010 114
APA dynamic properties
APA force limitsCeramic Prestress : typically designed to about half blocked stress of the piezo ceramicforce limit at the actuator level Fmax : half the max actuator blocked force Fa :
Fmax = Fa/2
This criteria is used to analyse the limitation of the actuator in dynamic conditions, including resonance
04/06/2010 1 Day Piezo Training 2010 115
APA dynamic properties
Prestress of Piezo Ceramic :Needed as it cannot bear tensile stress
APA stress budget considered at the design :prestress stress : static stresses from the prestress process.actuation stress : stresses produced in the shell when the ceramic is supplied. external force stress : stresses due to external vibrations or shock or applied forces.
⇒ No weak point in APAs :No hinges, elastic pivot..
04/06/2010 1 Day Piezo Training 2010 116
APA dynamic properties
APA force limitsCeramic Prestress : designed to half blocked stress of the piezo ceramicforce limite at the actuator level Fmax : half the max actuator blocked force Fa :
Fmax = Fa/2
This criteria is used to analyze the limitation of the actuator in dynamic conditions, including resonance
04/06/2010 1 Day Piezo Training 2010 117
APA dynamic properties
APA120ML in blocked-free with M=180g & Q=10
Static propertiesFree displacement : ua = 130µm @170VDisplacement per volt : u/V = 0,76µm/VBlocked force : Fa = 1400N @150V
Dynamic limitsMax voltage : Vmax = 170Vpp = 85Vp
Max dynamic force due to prestress : Fmax = 700N
Analysis with COMPACT tool based on eq circuit
04/06/2010 1 Day Piezo Training 2010 118
APA dynamic properties
APA120ML in blocked-free with M=180g & Q=10
04/06/2010 1 Day Piezo Training 2010 119
APA dynamic properties
APA120ML in blocked-free with M=180g & Q=10
04/06/2010 1 Day Piezo Training 2010 120
APA dynamic properties
APA120ML in blocked-free with M=180g & Q=10
Voltage limit Force
limit
04/06/2010 1 Day Piezo Training 2010 121
APA dynamic properties
APA120ML in blocked-free with M=180g & Q=10
Voltage limit
Force limit
04/06/2010 1 Day Piezo Training 2010 122
APA dynamic properties
APA120ML in blocked-free with M=180g & Q=10Thanks to prestress : Fmax = 700N
umax > 120 µm between 0 and 1000Hz
If low prestress : Fmax = 70Numax > 100 µm between 0 and 200Hzumax = 15 µm at 1000Hz
⇒ Prestress allows to get high displacements in a large bandwidth
⇒ Advantage for dynamic applications such as scanning, active damping, vibration generators ...
04/06/2010 1 Day Piezo Training 2010 123
Mechanical integration issues
Type Pre-stress Mechanical interfacesfor actuator ‘s fixing
Mechanical interfacesfor payload ‘s fixing
Mountingtechniques
Quick Pack NO NO NO GlueBimorph NO NO NO GlueRing Bender NO NO NO GlueThunder YES YES NO Glue / ScrewDPA YES YES (Threaded Hole) YES (TH) Glue / ScrewPPA YES YES (TH) YES (TH) Glue / ScrewAPA YES YES (TH) YES (TH) Glue / Screw
04/06/2010 1 Day Piezo Training 2010 124
Conclusion about APAs
Use of Ceramic Multilayer Actuators
Use of an elastic amplifier with amplification ratio in the range 2 - 10
Optimization of the efficiency using FEM
Includes a high prestress to get good dynamic properties
04/06/2010 1 Day Piezo Training 2010 125
Mechanisms
Multi axis actuation
04/06/2010 1 Day Piezo Training 2010 126
Mechanims
At least one active axis : Possibility of several degrees of freedom (dof)
Linear motion, rotation motion, combinations
Passive axis controlled by guidingActive axis could be geared
04/06/2010 1 Day Piezo Training 2010 127
XY orthogonal stages
Courtesy of PI
Neither mechanically centred nor thermally compensated
Stack of 2 linear stages
• slow response time
• risk of orthogonality error
• No axis runout compensation
Monolithic but nested module
• No axis run out compensation
Monolithic but nested module
• Run out & cross talk
compensation in closed loop
04/06/2010 1 Day Piezo Training 2010 128
This stage, [+/-100µm]x[+/-100µm], is mechanically & electrically centred and thermally compensated
Active Control of Position :Symmetric XY stage XY200M
XY orthogonal stages
04/06/2010 1 Day Piezo Training 2010 129
XY micro sanner piezo stage : Improvement of Camera Sensor Resolution
ApplicationsEmbedded IR cameras
> 100 THALES cameras> 400 piezo actuators
Future space missionsIR cameras / telescopes
XY microscanners for improving resolution of Infra Red cameras
Push-pull stage based on APA25XS
04/06/2010 1 Day Piezo Training 2010 130
Piezo Mechanisms with several dof
Hexapode HEX100M
Tx = Ty = 65 µm; Tz = 57 µm
Rx=Ry= 2.7 ; Rz= 1.1 mrad (+/-)
XYZ200M-SG
Tx=Ty= +/- 100 µm ; Tz = 200 µm
04/06/2010 1 Day Piezo Training 2010 131
Single axis - linear stage
X60SMPush pull configuration
Mechanically & electrically centred
Thermally compensated
Very low parasitic motions
stroke = 60 µm
04/06/2010 1 Day Piezo Training 2010 132
The tip-tilt mechanisms are the most simple structures that can perform one or two rotations, plus a vertical (z) actuation :
Space qualified DTT35XSCourtesy of CNES Pharao project
one rotation: +/- 0.5° two rotations: +/- 2mrad
TT50S
Tilt Mechanisms
04/06/2010 1 Day Piezo Training 2010 133
Objective Piezo Positioner
References Unit OPP120SMNotes Preliminary dataSensors option ECLActive axis TZMax. No-load displacement µm 90Max. parasitic X Y rotations µrad 140Voltage range V -20 … 150Resolution nm 9Stiffness N/µm 1,11Heigth mm 50,0Dimensions mm 65 * 40Mass g 170Unloaded resonance frequency (in the actuation's direction) Hz 450
Response time ms 1,11Loaded resonance frequency (in the actuation's direction) load = 200 g Hz 285
Loaded response time ms 1,75Capacitance (per electrical port) µF 3,15
Mechanical interfaces (payload) object ive interface to be specif ied
Mechanical interfaces (frame) tbd
Electrical interfaces 1 RG178B/U coaxial cable
04/06/2010 1 Day Piezo Training 2010 134
Fast Piezo Shutter FPS200M
Technical Features with dedicated SP75 driving electronics :
Aperture > 300 µm; response time < 2 ms; Overshoot < 10%; low jitter;
04/06/2010 1 Day Piezo Training 2010 135
Conclusion about mechanisms
Combinations of several dofPush pull configuration to cancel thermo- mechanical issueGuiding and closed loop needed to compensate or cancel parasitic motionsCompatibility in option with severe environment (UHV, Cryogenic, Non magnetic, Space …)
04/06/2010 1 Day Piezo Training 2010 136
Driving & control electronics for piezoelectric actuators & mechanisms
04/06/2010 1 Day Piezo Training 2010 137
Introduction
Specifity of piezoelectric loads, different cases (static, quasistatic, resonant),Basics of amplifiers,Practical implementations,Control of piezoelectric actuators,Conclusion.
04/06/2010 1 Day Piezo Training 2010 138
Introduction – load & frequency
Piezoelectric actuators constitute capacitive resonant loads: pretty high stress generated in the active switches Different types of applications :
Static : load of a capacitance; compensation of dielectric losses,
Dynamic : reactive load, I = jωC.V (out side resonance)
Resonance : Complex load
0,00E+00
2,00E-03
4,00E-03
6,00E-03
8,00E-03
1,00E-02
1,20E-02
1,40E-02
1,60E-02
1,80E-02
2,00E-02
0,0000 0,1000 0,2000 0,3000 0,4000 0,5000 0,6000 0,7000 0,8000 0,9000Frequency [kHz]
[S]
-20
0
20
40
60
80
100
Mod(Y) [S]Phase(Y) [°]
[°]
© Cedrat Technologies - COMPACT v4.33
Admittance Curve Y=I/V
04/06/2010 1 Day Piezo Training 2010 139
Introduction – driving signal
Definition of the output signals voltage&CurrentDC, sine or square signal
04/06/2010 1 Day Piezo Training 2010 140
Linear amplifier for static / dynamic applications
For a given amplifier, having a given current limitation, Bandwidth varies with the actuator capacitance
Bandwidth using a 40W Vcc source
Frequency Response of the LA75 Linear Amplifieragainst various Capacitive Loads
020406080
100120140160180200
1 10 100 1000 10000Frequency (Hz)
Volta
ge ra
nge
(V)
C = 0,7 µFC = 2,2 µFC = 24,0 µF
04/06/2010 1 Day Piezo Training 2010 141
Dynamic applications : example with a linear amplifier
V = -R1 / R2 VinRequired electrical power
Electrical current i = 2π f V Cbf
Electrical power dissipated in the amplifier, P = 4V2 f Cbf
Numerical example : Cbf = 1 µF, V=100V, f = 2 kHzi = 1.3 A, P = 80 W
04/06/2010 1 Day Piezo Training 2010 142
Example of dynamic application: APA500L
Standard APA500L features:
Displacement = 500 µm
Blocked force = 560 N
Resonant Freq. = 460 Hz
C = 40 µF
Peak Amplitude vs frequency
Displacement = 500 µm @ 100 Hz
Driven by a LA75C-1 from Cedrat T.
04/06/2010 1 Day Piezo Training 2010 143
Noise in static / dynamic applications
Noise in static applications : 80 mV/ @ 50V = 0.16 %80 dB signal to noise ratio can be obtained through a correct shield.100 dB signal to noise ratio obtainable at the expense of a reduced bandwidth
04/06/2010 1 Day Piezo Training 2010 144
Amplifiers for static applications 2 principal classes:
The linear amplifier, A, B or AB classes,The switching amplifier D classes and Co,
Characterised by:Output current,Output voltage,Bandwidth,Gain,Capacity to drive reactive loads,THD,SNR,Protections
04/06/2010 1 Day Piezo Training 2010 145
Basics of amplifiers
Use of a the traditional linear amplifier
PZTRg
R1
R2
Vin
Cbf
04/06/2010 1 Day Piezo Training 2010 146
Basics of amplifiers
Class A amplifiers : dynamic behavior around the static polarisation point,
Low efficiency on a resistive load : 25 %,
04/06/2010 1 Day Piezo Training 2010 147
Basics of amplifiers
Class B amplifiers :The characteristics is influenced by the non – linear characteristics of the transistors around the static point => pretty high distortion.
04/06/2010 1 Day Piezo Training 2010 148
Basics of amplifiers
Resulting distortion of the Class B amplifier,Efficiency on a resistive load = 78 %
04/06/2010 1 Day Piezo Training 2010 149
Basics of amplifiersClass A-B amplifiers : cancellation of the distortion through diodes or junction multipliers
04/06/2010 1 Day Piezo Training 2010 150
Basics of amplifiersClass D (switching) amplifiers : high frequency on / off operations and filtering,Half-bridge and Full bridge topologies (depending on load) :
Half bridge is used for capacitive load,Full bridge is used for inductive load.
04/06/2010 1 Day Piezo Training 2010 151
Basics of amplifiers
Class D (switching) amplifiers :On-off control through PWM in open loop,Filtering function is often necessary to reduce to output voltage ripple.
04/06/2010 1 Day Piezo Training 2010 152
Basics of amplifiers : Synthesis
HighLowLowLowMaximal power
LowImportantImportantImportantDimensions(for a given load)
HighMediumMediumVery lowEfficiency
HighLowLowLow Noise
LowLowMediumLowDistortion
High (require high frequency switching)
High High High Bandwidth
HighBipolartransistor
HighHighHighVoltage
Class DCommentsClass ABClass BClass A
Switching AmplifierLinear AmplifierCriteria
04/06/2010 1 Day Piezo Training 2010 153
Basics of amplifiers : Synthesis
04/06/2010 1 Day Piezo Training 2010 154
Basics of amplifiers : Synthesis
04/06/2010 1 Day Piezo Training 2010 155
Amplifiers for Dynamic applications
Linear amplifier : high reactive load,design of heat sinks necessary,
Switching amplifier : More complex control strategy,Possibilities for energy recovery.
04/06/2010 1 Day Piezo Training 2010 156
Dynamic applications
Schematic of a switching amplifier
04/06/2010 1 Day Piezo Training 2010 157
Dynamic applications
Schematic of a switching amplifier
04/06/2010 1 Day Piezo Training 2010 158
Dynamic applications
Basic circuit
04/06/2010 1 Day Piezo Training 2010 159
Dynamic applications
Switching strategy including energy recovery
04/06/2010 1 Day Piezo Training 2010 160
Dynamic applications : Conclusion
Energy recovery and precise charging results from a compromise,Switching strategy should be monitored through a numerical controller.Monitoring the charge (and the resulting displacement) may be used as an alternative strategy.
04/06/2010 1 Day Piezo Training 2010 161
Introduction - control
Static & dynamic : controller (PID) to remove the hysteresis,Charge controlled versus voltage controlled amplifiers,
04/06/2010 1 Day Piezo Training 2010 162
Control in static applications
Very high position accuracy can be obtained with piezoelectric actuatorSensors for a closed-loop system
strain gaugecapacitive displacement sensorEddy current sensor
04/06/2010 1 Day Piezo Training 2010 163
Control in quasi-static applications
Typical structure of an analogue controller :PI + Filter topology
Typical step response
04/06/2010 1 Day Piezo Training 2010 164
The Strain gauges are the most simple sensor :Use of a complete Wheastone bridge bonded on the MLA to achieve the best sensitivity.Example of a APA50S with strain gauges :
Control in quasi-static applications
04/06/2010 1 Day Piezo Training 2010 165
Static applications
Removal of the creep effect (process of repoling)
Actuator's displacement (µm) - Record of the creep effectusing a capacitive displacement sensor
0,00
20,00
40,00
60,00
80,00
100,00
120,00
140,00
0 200 400 600 800 1000 1200 1400 1600
Time (s)
Disp
lace
men
t (µm
)
04/06/2010 1 Day Piezo Training 2010 166
Static applications
Removal of the hysteresis
Removal of the piezoelectric actuator hysteresis using a displacement sensor
0
1
2
3
4
5
6
7
8
9
0 2 4 6 8 10
Order (Volts)
disp
lace
men
t mea
sure
men
t (Vo
lts)
closed loop off
closed loop on
04/06/2010 1 Day Piezo Training 2010 167
Static applications
Alternative hysteresis removal method by using an electrical charge control,The control is more complex.
04/06/2010 1 Day Piezo Training 2010 168
Static applications
Charge amplifier:
04/06/2010 1 Day Piezo Training 2010 169
Static applications
Charge amplifier:
04/06/2010 1 Day Piezo Training 2010 170
Conclusion
Piezo actuators constitute mainly capacitive loads ; it can differ for resonant applicationsThe reactive power requires attentionQuasi static applications & use of MLA can use PWM driver, without step-up transformer
04/06/2010 1 Day Piezo Training 2010 171
SP75 : Switching Power for driving Actuators in fast on-off motion
Options available: PID and Micro Controller for feedback and monitoring through a PC, via USB or RS-232 .
Driving Electronics for Piezo Actuators & Mechanisms
CA45 & LA75A : Linear Amplifier for driving Actuators with low noise for precise & quasi-static motion
LA75B & LA75C: Linear Amplifier for driving Actuators in power demanding dynamic motion
See technical data sheets in the “Piezo Products catalogue”
04/06/2010 1 Day Piezo Training 2010 172
How to choose the right actuators and driving electronics ?
04/06/2010 1 Day Piezo Training 2010 173
How to chose the right actuator ?
Depending on the type of applications, several parameters govern the selection of the actuator :
Static Dynam ic Im pulse
Param eters ofthe actuatorStroke X X X
Stiffness
Bandwidth X XElectricalcapacitance
X X
Param eters ofthe applicationPayload m ass X X
Parallel stiffness X X X
M ax. current ofthe driver
X X
04/06/2010 1 Day Piezo Training 2010 174
How to chose the right actuator ?
Frequency / response time considerations in dynamic applications
Controllable frequencies : f< fmax = fr/3Impulse response : tmin = 1/(3*fr) =T/3
fr= device resonance frequency
04/06/2010 1 Day Piezo Training 2010 175
Equivalent circuit & associated data
Displacement Transient response for a step voltageOvershot effectsStabilisation time
Step response
0
1
2
0 1 2 3 4 5 6 7 8t / T
u / u
0
High QLow Q
04/06/2010 1 Day Piezo Training 2010 176
Arrangement of piezo-actuators
Parallel arrangement adds force Serial arrangement adds displacement
04/06/2010 1 Day Piezo Training 2010 177
Deriving the electrical circuit from the actuator ’s properties
Stiffness k, modal mass m, unloaded resonance frequency fr, capacitance CBF, force factor N, voltage V, blocked force F, payload mass M, motional capacitance Cm, clamped capacitance C0, m = k/(2πfr)2 ; N = F/V ; Cm = N2/kC0 = CBF - Cm Loaded fr = 1/2π (k/(m+M))1/2
04/06/2010 1 Day Piezo Training 2010 178
Exercices
How to select piezo actuators, associated mass and electronics ?Analytical modelsFinite element models
COMPACT tool Excel tool based on an analytical modelFree ware, download from Cedrat webFast way for pre-dimensioning or selecting components
04/06/2010 1 Day Piezo Training 2010 179
Exercice 1: Slow positioning of an optic
A summary of the specifications is given in the table beside :
Application is optic positioning in lab environment
5Max Frequency(Hz)
400Max Displacement
(µm)
1000Payload Mass (g)
RequiredSpecs
04/06/2010 1 Day Piezo Training 2010 180
Exercice 2: Fast positioning of a tool
A summary of the specifications is given in the table beside :
Application is oval piston machining
100Max Frequency(Hz)
100Max Displacement
(µm)
2000Payload Mass (g)
RequiredSpecs
04/06/2010 1 Day Piezo Training 2010 181
Exercice 3: Ultrasonic vibrations
A summary of the specifications is given in the table beside :
Application is ultrasonic glass cutting
20 000Frequency (Hz)
6Displacement(µm)
3Payload Mass (g)
RequiredSpecs
With PiezoactuatorAssistance
Without Piezoactuator Assistance
Courtesy of Schott
04/06/2010 1 Day Piezo Training 2010 182
Example 4: Pulsation force Generation
A summary of the specifications is given in the table beside :
Application is Anti-vibration for a turbo-engine aircraft cabin (ATR42)
100-500Frequency (Hz)
8-10NForce (N)
100 KqPayload Mass (g)
RequiredSpecs
04/06/2010 1 Day Piezo Training 2010 183
Example 5: Fast response
A summary of the specifications is given in the table beside :
Application is Piezo injectors for fuel injection
<1msResp.time (ms)
>60µmStroke (N)
0,015 KqPayload Mass (g)
RequiredSpecs
04/06/2010 1 Day Piezo Training 2010 184
Illustration of limitations in dynamic applications
Current limitation of the driving electronics (working frequency)Force limitation of the piezo actuator (Payload mass & working frequency)Self heating limitation of the piezo ceramic (Duty cycle)
=> Computations and curve analysis (Cedrat Technologies Excel sheets - COMPACT tool)
04/06/2010 1 Day Piezo Training 2010 185
Current limitation
APA120ML + 1 kg in blocked free condition (Resonant Freq = 0,5 kHz) driven by a LA75A-1 (Imax peak = 90 mAmps)
04/06/2010 1 Day Piezo Training 2010 186
Power and Force Limitations
APA120ML + 1 kg in blocked free condition (Resonant Freq = 0,5 kHz) driven by a LA75C-1 (Imax peak = 2,4 Amps)
04/06/2010 1 Day Piezo Training 2010 187
Adiabatic Self Heating
APA120ML + 1 kg + LA75C-1
APA120ML + 1 kg + LA75A-1
04/06/2010 1 Day Piezo Training 2010 188
Piezo Motors Overview
04/06/2010 1 Day Piezo Training 2010 189
Different types of piezoactive motors
‘INCHWORM’ motors : high resolution, low speed.Inertial Step Motors (ISM) : simple structure, multiple degrees of freedom, high potential for micronization.Ultrasonic motors (USM) : large torque at low speed and at rest,silent and nonmagnetic operation, excellent dynamic characteristics.
04/06/2010 1 Day Piezo Training 2010 190
‘Inchworm’ motors
Use of active grips and active member along a rail & combination of activations of grips and active member.
04/06/2010 1 Day Piezo Training 2010 191
‘Inchworm’ motors
Linear inchworm CIMMS Virginia Tech M.Vaughan ,D.J.Leo from US Center for Intelligent Material Systems & Structures, Integrated piezoelectric linear motor for vehicule applications, Proc IMECE02/TTRST-32942, ASME Symp., New Orlean US, Nov.17-22, 2002,, 9p.
Inchworm with APA120ML
04/06/2010 1 Day Piezo Training 2010 192
CEDRAT piezo motor stepping solution
Use of at least two Amplified Piezo Actuators
Anchor point
(a) driving stage
(b) return stage
Slider (or rotor) Driving direction
04/06/2010 1 Day Piezo Training 2010 193
LISA Laser Interferometer Space Antenna
High Pointing Precision Piezo MotorPrinciple
Normal displacement : same voltage supply Tangential displacement : opposite voltage supply
Anchorpoint
MLA-1 MLA-2
Anchorpoint
Amplified Piezo Actuators APA with the piezo ceramics driven : in phase (left) / in opposition (right)
04/06/2010 1 Day Piezo Training 2010 194
LISA Laser Interferometer Space Antenna
High Pointing Precision Piezo MotorAccuracy <100nradresolution < 5nradnon magneticno lubricant
LISA HP Piezo Motor Breadboard (courtesy of ESA)
04/06/2010 1 Day Piezo Training 2010 195
Inertial step motors (ISM)
Working principle:sudden contractio: inertia effectslow contraction: no inertia
04/06/2010 1 Day Piezo Training 2010 196
Inertial step motors (ISM)
reliability for multiple degrees of freedom motion : for instance, a piezoelectric XY micrometric stage
04/06/2010 1 Day Piezo Training 2010 197
Inertial step motors (ISM)
Rotating ISMNew Focus active screw = pico motor
04/06/2010 1 Day Piezo Training 2010 198
CEDRAT New miniature linear piezo motors
SPA Stepping Piezo Actuator from CedratNew APA-based piezo motorsGolden Micron 2008 at MicronoraCedrat patent
04/06/2010 1 Day Piezo Training 2010 199
SPA Stepping mode Principle4 components
Stick-Slip step excited by a saw tooth signalAccumulation of steps to get a long stroke (several mm)
SPA60SM Animated Principle (2 steps) One stick-slip step
Mass APA (piezo) Rod Clamp
CEDRAT New miniature linear piezo motors
04/06/2010 1 Day Piezo Training 2010 200
New miniature linear piezo motors : SPA
SPA combined modes for Nano positioningStepping mode (M1)
Saw tooth signal Stick-slip of the rod in the clamp
Deformation mode (M2)Load fixed on the MassAPA deformation proportional to voltage
One stick-slip step (M1)
Long stroke combining Stepping (M1) and Deformation (M2) Modest
u1
M1 M2
04/06/2010 1 Day Piezo Training 2010 201
New miniature linear piezo motors : SPA
SPA tests : Combined M1–M2 modes for Nano positioningAchieved precision : 60nm (due to sensor) Achieved resolution : 0.5nm (due to amplifier)
Long stroke combining Stepping (M1) and Deformation (M2) Modes, and associated electric excitation
SPA35XS bench with sensor
04/06/2010 1 Day Piezo Training 2010 202
New miniature linear piezo motors : SPA
SPA AdvantagesSimple APA-based structure
Reliable, large heritage from APA
One channel electronicsScalable
Various APA size and forces
High degree of miniaturization
Cryogenic versionsNon- magnetic versions (MRI-compatible)
Firm connection between the load and the motor Fine positioning with nanometer resolution on a large range (due to the APA amplified stroke) Cost effective approach
SPA30uXS
04/06/2010 1 Day Piezo Training 2010 203
New CEDRAT miniature linear piezo motors
SPA performances
References Unit SPA uXS-S SPA uXS-F SPA XS-S SPA XS-F SPA SM-S SPA SM-FNotes Preliminary Preliminary Preliminary Preliminary Preliminary PreliminaryBase APA30uXS APA30uXS APA35XS APA35XS APA60SM APA60SMLong stroke (M1) mm 4 4 10 10 20 20Stiffness (M1) N/µm 0,108 0,108 0,49 0,49 1,38 1,38Max speed (M1) mm/s 70 30 30 5 30 5Blocking force at rest (M1, M2) N 0,4 0,8 3 6 15 30Max actuation force (M1) N 0,1 0,3 1 2 5 10Short high resolution stroke (M2) µm 30 30 55 55 80 80Resolution (M2) nm 1,7 1,7 3,1 3,1 4,5 4,5Bandwidth (M2)** kHz 3,2 3,2 0,6 0,6 0,6 0,6Capacitance (M1, M2) µF 0,052 0,052 0,25 0,25 1,55 1,55Height along active axis mm 15 15 30 30 50 50Base size mm2 5 x 9 5 x 9 16 x 16 16 x 16 27 x 27 27 x 27Inertial mass gr 0,27 0,27 30 30 70 70Mass gr 2 2 50 50 120 120Max current consumption mA 60 60 60 60 350 350Holding current mA 0 0 0 0 0 0LA75 types compatibility A - B - C A - B - C A - B - C A - B - C B - C B - CCA45 compatibility yes yes yes yes no no
04/06/2010 1 Day Piezo Training 2010 204
What are ultrasonic motors ?
Use piezoelectric material to produce a small elliptical displacement in the stator,Drive a moving member through friction forces.
04/06/2010 1 Day Piezo Training 2010 205
Ultrasonic Motors : USM classification
Travelling Wave Ultrasonic Motors (TWUM)Standing Wave Ultrasonic Motors (SWUM)Hybrid Type Ultrasonic Motors (HTUM)Mode Conversion Ultrasonic Motors (MCUM)Multi Mode ultrasonic motors (MMUM)Mode Rotation Ultrasonic Motors (MRUM)
04/06/2010 1 Day Piezo Training 2010 206
Travelling Wave Ultrasonic Motors (TWUM)
Excitation of a rotating flexural mode in an elastic ring.
04/06/2010 1 Day Piezo Training 2010 207
Machining tolerance of contact surfaces
- Flatness
- Roughness
Geometric conformity of static contact
04/06/2010 1 Day Piezo Training 2010 208
Mode Conversion Ultrasonic Motors (MCUM)
Newscale Technologies -> Squiggle motor
AF system
04/06/2010 1 Day Piezo Training 2010 209
Design of multi-modeultrasonic motors
Working principle (patented Cedrat technology) :
04/06/2010 1 Day Piezo Training 2010 210
Design of multi-mode ultrasonic motorsTwo vibrations modes
Flexural modeexcitation in phasenormal displacement
Translation modeexcitation opposite in phasetangential displacement
04/06/2010 1 Day Piezo Training 2010 211
LPM20-3 using a LVDT position sensor
04/06/2010 1 Day Piezo Training 2010 212
LPM20-3 Load characteristic
Perfomances of standard LPM20-3 measured in 1999
04/06/2010 1 Day Piezo Training 2010 213
Friction layers’ properties
Thermal stabilityElasticity : dynamic interpenetration at the interfaceAbsence of noise generated by slidingSize of the third body particles Wear resistance : fibbers & powder reinforced polymer
04/06/2010 1 Day Piezo Training 2010 214
Wear aspects in piezomotors
Critical role of the fibbers use to reinforce the polymer.Surface after 520,000 actuation's in vacuum :
polymer vibrating steel
Frictional directionFrictional direction
04/06/2010 1 Day Piezo Training 2010 215
Wear aspects in piezomotors
A stable frictional coefficient of 0.45 is obtained after an adequate running procedure,No change of performances after 520,000 strokesView of the wear zone :
04/06/2010 1 Day Piezo Training 2010 216
Conclusion for piezo motor tribology
Mechanism of preload applicationRunning aspects Stability of shift velocity accommodation mechanismsDebris evacuation device
04/06/2010 1 Day Piezo Training 2010 217
Driving piezo motor
Inchworm / ISM => Standard electronics similar to piezo actuator drive,USM : resonant load
switched inverters are generally used,automatic frequency resonance tracking necessary,non linear behaviour of the USM for the automatic point of view.
04/06/2010 1 Day Piezo Training 2010 218
Piezomotors : conclusion
Motors useful for positioning applications,Superior torque / mass ratio,Current applications in microelectronic, space,Difficult subject,Development require multidisplinary skillness (piezoelectricity, mechanics, tribology, electronic, automatic, …).
04/06/2010 1 Day Piezo Training 2010 219
Applications using piezo actuators
CEDRAT TECHNOLOGIES REFERENCES
04/06/2010 1 Day Piezo Training 2010 220
Applications for piezo actuators
Optics , Air & SpaceValvesActive damping ActuationMachine tools Telecom
Electrical generator Reclamation
04/06/2010 1 Day Piezo Training 2010 221
Standard Actuators Products
04/06/2010 1 Day Piezo Training 2010 222
Standard Actuators Products
04/06/2010 1 Day Piezo Training 2010 223
Standard Drivers / Conditionners Products
04/06/2010 1 Day Piezo Training 2010 224
Optics Air & Space
Identified ApplicationsActive vibration controls of electronics,instrumentsActive vibration controls in cameras, telescopesImprovement in CCD/CMOS cameras resolutionRefocusing of space telescopesActive optical filters, extended cavity lasers,Active Flaps of Helicopter blade, Missiles, DronesActive Flaps of Air plane (mock-up) flaps, Active shape control of wings Direct drive of Hydraulic jacks Scanning function in fine space instruments ...
04/06/2010 1 Day Piezo Training 2010 225
Optics, Air & Space
Id. applications needs Actuators with:High output energy to mass ratioLow power consumptionResistance to severe environment (esp vibrations)High bandwidthHigh resolution
Cedrat Response:Piezo Actuators based on pre-stressed MLAMLA = low voltage multilayer piezo ceramicsDesign under ECSS standards + Qualification
04/06/2010 1 Day Piezo Training 2010 226
Piezo Actuators & Electronics: Application for Space Telescopes
5 dof mechanism for telescope secondary mirror
BERTIN mechanism using CEDRAT APA120ML actuators & electronics
04/06/2010 1 Day Piezo Training 2010 227
Piezo Actuators & Electronics: Space Qualification
‘FB-LA75A’ electronicsFly-Back DC-DC converter (from 20-50V to 150V) Linear Amplifier for Piezo ActuatorsStrain Gage conditionerAnalog Servo controller
Space qualificationEEE components analysisRadiation analysisThermal analysisEMC analysisMechanical analysisThermal-Vacuum tests
FB-LA75A space electronics for piezo actuators from CEDRAT
TECHNOLOGIES
04/06/2010 1 Day Piezo Training 2010 228
• FM Piezo mechanism including SMA latch actuators
Flight model on board ROSETTA satellite, flying since Feb. 2004 displacement = [100*100*8] µm resolution = 4 nm successful commissioning !successful commissioning !
CAD view of XYZ piezo stage : 9 Piezos : 8 APA50S + 1 PPA10M
+ 2 SMA latch actuators + positions/check sensors
Dust analysis of the comet, heart of MIDAS AFM instrument (Courtesy of ESA, European Space Agency)
Active Control of Position (scanning):Space XYZ stage for ROSETTA/MIDAS
04/06/2010 1 Day Piezo Training 2010 229
This stage, [+/-100µm]x[+/-100µm], is mechanically & electrically centred and thermally compensated
Space qualified model
( Courtesy of CNES, French Space Agency )
Closed loop options: Strain Gages or Capacitive Sensors
Normally centred piezo mechanisms:Symmetric XY stage XY200M
04/06/2010 1 Day Piezo Training 2010 230
Application for Improvement of Camera Sensor Resolution
Over-sampling technique 4 successive pictures (n° 1 to 4) are merged. The distance between points correspond to 1/2 sensor pixel. The XY stage carries either a lens or the CCD itself.
Principle of the over – sampling
Lens motion produced by the XY micro scanner to perform over-sampling
04/06/2010 1 Day Piezo Training 2010 231
Application for Improvement of Camera Sensor Resolution
Improvement provided by over-sampling technique
Improved images using over-sampling technique
04/06/2010 1 Day Piezo Training 2010 232
Application for Improvement of Camera Sensor Resolution
Cedrat XY micro scannersPush-pull stages based on 4 APA25XSMonolithic designThermally compensatedStroke [-15µm +15µm]²Open loop controlQualified :
Operation in vibrationTemperature -40 +80°CLife time
XY microscanners manufactured by CEDRAT TECHNOLOGIES
04/06/2010 1 Day Piezo Training 2010 233
Application for Improvement of Camera Sensor Resolution
Applications of Cedrat XY micro scanner piezo stageEmbedded IR cameras
> 1000 THALES cameras> 1000 Microscanners> 4000 piezo actuators
Future space missionsIR cameras / telescopes
THALES Catherine MP LWIR QWIP Camera
Courtesy of THALES OL
04/06/2010 1 Day Piezo Training 2010 234
Normally centred piezo mechanisms: Tilt Mechanism for laser pointing
DTT35XS PHARAO Double tilt : a space MOEMSMOEMS = Micro Optical Electro Mechanical SystemControl of a mirror on 2 dof in rotation (Rx, Ry)Key Components:
1 Mirror 4 Hinges4 APA35XS Actuators 4 Strain Gages Sensors (bonded on PZT MLA)
04/06/2010 1 Day Piezo Training 2010 235
DTT35XS PHARAO Double tilt : a space MOEMSMass = 15 gr (2gr per actuator)Rx, Ry = +/- 2mrad (Tz = 20µm is not used)Positioning Precision = 1µrad r msTemperature = -40°C / +75°CPassed qualifications :
Life timeVibrationShocksThermal Vacuum cyclingNon magnetism...
Normally centred piezo mechanisms: Tilt Mechanism for laser pointing
04/06/2010 1 Day Piezo Training 2010 236
DTT35XS PHARAO Double tilt : a space MOEMSBatch of 10 Qualification Models of DTT35XS in casing delivered to EADS Sodern (Jan 2003) Batch of 8 Flight Models in production
Qualification Models of the PHARAO/MEF space piezomechanisms based on 4 APA35XS
(courtesy of EADS)
Normally centred piezo mechanisms: Tilt Mechanism for laser pointing
04/06/2010 1 Day Piezo Training 2010 237
Normally centred piezo mechanisms:A Rz mechanism for despinning correction
Correction of the spinned movement of the GAIA spacecraft on the CCD of the RVS instrument
Breadboard for GAIA/RVS space piezo mechanism based on 2 APA400M
(courtesy of Obs. Meudon)
04/06/2010 1 Day Piezo Training 2010 238
Fast Piezo Shutter FPS200M
Technical Features with dedicated SP75 driving electronics : Aperture > 300 µm; response time < 2 ms; Overshoot < 10%; low jitter;
Fast Piezo Shutter FPS200MQualification of 1 FPS200M (1 year test ) by ESRFBatch of 8 FPS200M delivered to ESRF
04/06/2010 1 Day Piezo Training 2010 239
Refocusing mechanisms (1/3)
External laser cavity tuning by a PPA10M Parallel Pre-stress piezo Actuator.
10 Flight Models planned for the end of 2004
PHARAO/LCE space piezo mechanism
(courtesy of EADS / SODERN)
04/06/2010 1 Day Piezo Training 2010 240
Refocusing mechanisms (2/3)
The dynamic refocusing of the 1st European LIDAR (ALADIN on board on ESA /AEOLUS).
The main difficulties are :
• The high bandwidth (> 2 kHz),
• The lifetime (4*1010 cycles).
4 QM/FM delivered before end 2004
ALADIN AEOLUS space refocusing piezo mechanism
(courtesy of GALLILEO Avionica)
04/06/2010 1 Day Piezo Training 2010 241
Refocusing mechanisms (3/3)
The piezo actuator is used to refocus a laser beam
ALADIN Lidar
(courtesy of GALLILEO)
04/06/2010 1 Day Piezo Training 2010 242
Piezo Actuators: Application for Helicopter Flap Control
Flap design proposed by CEDRATECHNOLOGIES in 1998
04/06/2010 1 Day Piezo Training 2010 243
Piezo Actuators: Application for Helicopter Flap Control
RPA Helicopter Project:Active trailing edge flaps on the main rotor for:
decrease BVI noise in descent flight improve the dynamic behaviour of the rotor throughout the largest possible flight domain
Work done by Onera (French Aircraft Design Inst.)Support of:
French Civil Aviation AuthorityMinistry of Defense (DGA)Eurocopter
04/06/2010 1 Day Piezo Training 2010 244
Piezo Actuators: Application for Helicopter Flap Control
Blade Vortex Interaction (BVI) noise:
04/06/2010 1 Day Piezo Training 2010 245
Piezo Actuators: Application for Helicopter Flap Control
Wind tunnel scale rotordiameter of the Mach-scaled rotor : 4.2 m the maximum blade chord : 140 mm the flap dimensions at wind-tunnel scale :
210 mm in span 21 mm in chord
geometrical reduction factor : 2.619
04/06/2010 1 Day Piezo Training 2010 246
Piezo Actuators: Application for Helicopter Flap Control
Requirements for the Mach-scaled rotor:− natural freq. of the flap/hinge axis : > 150Hz− min. flap deflection : ± 5°, 78 Hz, static moment of 1.22 Nm
for hinge centred at 0%− ideal flap deflection : ± 15°, 262 Hz, static moment of 4.9 Nm
for hinge centred at 0%− flap actuation frequencies : from 0 to 5-per-rev
with respect to rotor rotation speed − required energy/kg of actuators : > 150mJ/kg − maximum centrifugal field : 2300 g
04/06/2010 1 Day Piezo Training 2010 247
Piezo Actuators: Application for Helicopter Flap Control
Comparison of Actuators by ONERA for selection
⇒ Selection of the standard APAs from CEDRAT because of highest energy density
Maryland 1/7th scale blademodel
in-house fabricated
Maryland full scale bladePrototype
CEDRAT APA230For 1/ 2.62th modelmass production
CEDRAT APA500Lmass production
Actuatortechnology
Multi-layeractuator
configuration (8layers)
Piezostacks withL-L amplification
mechanism
Piezostacks inelliptic housing
Piezostacks in elliptichousing
Voltage ± 134V → ± 400 V 0-120 V 0- 200 V 0- 200 VMass of actuator 14 g 634 g 250 g 208 g
Blocked force ( F ) 8 N 20 N 1350 N 570 NMaximum stroke ( x ) 165 µm 889 µm 230 µm 500 µm
Stiffness 0.048 106 N/m 0.021 106 N/m 3.48 106 N/m 1.14 106 N/mResonance frequency above 150 Hz Above 150 Hz 800 Hz 450 Hznergy to weight ratio of
actuator24 mJ/kg 28 mJ/kg 310 mJ/kg 342 mJ/kg
Ratio of Energy.. /L-LEnergy..
0.44 1 5.86 6.45
Width (chord axis) 33 mm 71 mm 69 mm 55 mmLength (span axis) 60 mm 183 mm 140 mm 145 mm
Thickness 2 mm to 5 mm 19 mm 10 mm 10 mmPk-to-pk flap
deflection±11°.5 ±11°.5 ±4°.5 ±9°.5
04/06/2010 1 Day Piezo Training 2010 248
Piezo Actuators: Application for Helicopter Flap Control
Onera flap concept using APAs
04/06/2010 1 Day Piezo Training 2010 249
Piezo Actuators: Application for Helicopter Flap Control
ONERA Centrifugal tests rig
• APA actuator
• Dummy flap
• Strain gage
• Rotation sensor
• BRAVoS rig
04/06/2010 1 Day Piezo Training 2010 250
Piezo Actuators: Application for Helicopter Flap Control
ONERA Centrifugal tests results
Active flap based on the standard APA230L under 0g
Active flap based on the standard APA230L under 2000g
04/06/2010 1 Day Piezo Training 2010 251
Piezo Actuators: Application for Helicopter Flap Control
Selection between APA230L & APA500L
A c t u a t o r o p e r a t i o n c u r v e
-1,00
-0,50
0,00
0,50
1,00
-7 -5 -3 -1 1 3 5 7 9 11F l a p a n g l e ( ° )
Aer odynamic HingeMoment Envelope f orps i=0°-360°
H i n g e m o m e n t ( N m )
U = 0 V
U = 1 8 0 V
M +-7°0°+11°
Uppe r Sur f a c e
A P A 5 0 0 L
A P A 2 3 0 L
B loc king Mome nt
B loc king Mome nt
⇒ Selection of the APA500L for the aerodynamic test because of better performances
04/06/2010 1 Day Piezo Training 2010 252
Piezo Actuators: Application for Helicopter Flap Control
ONERA S3MA wind tunnel tests set-up
Accelerometers on flap and airfoil
Calibration on the model in the wind tunnel
04/06/2010 1 Day Piezo Training 2010 253
Piezo Actuators: Application for Helicopter Flap Control
ONERA S3MA wind tunnel tests results
Flap deflection versus Input Control Voltage (at Mach=0.3)
04/06/2010 1 Day Piezo Training 2010 254
ONERA S3MA wind tunnel tests results
Max Flap Deflections versus Wing Incidence (at Mach=0.3)
-8
-6
-4
-2
0
2
4
6
8
10
-2 0 2 4 6
Wi ng i nci dence ( °)
F l a p a n g l e ( ° )Ri ght f l ap angl e
Cent r al f l ap angl e
Lef t f l ap angl e
Piezo Actuators: Application for Helicopter Flap Control
04/06/2010 1 Day Piezo Training 2010 255
New actuator APA750XL designed for ONERAStroke = 1150µmForce = 920NEnergy to weight : 441mJ/kg
APA750XL prototype for ONERA (scale 1 flap) from CEDRAT TECHNOLOGIES
Piezo Actuators: Application for Helicopter Flap Control
04/06/2010 1 Day Piezo Training 2010 256
ONERA conclusion & perspectivesNo breakdown & Encouraging performances
ONERA perspectivesImprovement of the flap mechanism foreseen to get less than 8% loss of stroke @2300gNew centrifugal tests of APA500L flap plannedScale 1 tests using the new actuator APA750XLActuator improvements using composite shells
Piezo Actuators: Application for Helicopter Flap Control
04/06/2010 1 Day Piezo Training 2010 257
Piezo Actuators: Application for Air Plane Flap Control
Flap control of Air plane mock-up (AWIATOR)reduction of slipstream of Airbus A340
need for specific flat actuatorsstroke : 500µmforce : 700Nheight : 60mmthickness : 9mm
04/06/2010 1 Day Piezo Training 2010 258
Flap control of Air plane mock-up (AWIATOR)ONERA pre-selection : APA500L
stroke u= 500µmforce F= 560N => Pb / 700Nheight : 55mmthickness : 10mm => Pb / 9mmLength : 145mm
Standard APA500L-SG from CEDRAT TECHNOLOGIES
Piezo Actuators: Application for Air Plane Flap Control
04/06/2010 1 Day Piezo Training 2010 259
CEDRAT offer to ONERA : an APA500L-SV Customised product starting from the APA500L (SV = special version) Reduction of thickness : 10mm => 9mmOptimisation of the Force F, keeping constant the stroke u and the same PZT amount Reduction of capability to withstand external vibrations, noting that vibrations are smaller in this application than in space launching conditions
Piezo Actuators: Application for Air Plane Flap Control
04/06/2010 1 Day Piezo Training 2010 260
Results on APA500L-SV developed for ONERAActuator APA500L APA500L-SV GainThickness 10mm 9mm -9%Mass m 0.20 kg 0.17 kg -15% Stroke u 500 µm 560 µm +11%Force F 570 N 778 N +36%Emec=F.u/4 0.071 J 0.109 J +53%Emec/m 0.35 J/kg 0.64 J/kg +82%
Piezo Actuators: Application for Air Plane Flap Control
04/06/2010 1 Day Piezo Training 2010 261
ConclusionsAPA500L-SV is fully compliant with ONERA needsStandard APAs are designed for Space need and are not optimised for all applications (even if they possess highest power density on the market)APAs can be optimised for other needs than space, such as Aircraft applications, leading to significant improvements in energy densities
Piezo Actuators: Application for Air Plane Flap Control
04/06/2010 1 Day Piezo Training 2010 262
Application for Mini Helicoptere
Mufly project
Micro APA APAµXS for
wing orientation (0.2gr)
Mini BDLC motor for wing rotation
(3gr)
04/06/2010 1 Day Piezo Training 2010 263
Piezo Actuators & Electronics: Application for proportional valves
Valve for micro thrusters : Implementation in a cold gas micro propulsion system
04/06/2010 1 Day Piezo Training 2010 264
Valve for micro thrustersCold gas (Nitrogen)APA200M actuator placed outside the gas
Proportional Piezo Valve from CEDRAT TECHNOLOGIES
Piezo Actuators & Electronics: Application for proportional valves
04/06/2010 1 Day Piezo Training 2010 265
Valve for micro thrusters : Results
Flow control in open loop Flow control with a feedback loop
Piezo Actuators & Electronics: Application for proportional valves
04/06/2010 1 Day Piezo Training 2010 266
Piezo Actuators : Application for Aircraft Hydraulic jacks
Piezo-based EHA (Electro Hydrostatic Actuators)R&D works performed in co-operation with SABCA, ZFL, ALENIA, SAAB, ZIP ...Goal : Improving EHA with smart actuators :
piezoelectrics actuators piezomagnetics (biased magnetostrictives)
Expected improvementsMassPower consumption Bandwidth
04/06/2010 1 Day Piezo Training 2010 267
Piezo-based EHA (Electro Hydrostatic Actuators)1 hydraulic jack2 actuated valves1 actuated pump1 accumulator(not shown)
Piezo Actuators : Application for Aircraft Hydraulic jacks
04/06/2010 1 Day Piezo Training 2010 268
Piezo-based EHA (Electro Hydrostatic Actuators)
Piezoelectric or magnetostrictive Valves & Pump for an EHA prototype designed by CEDRAT TECHNOLOGIES
Piezo Actuators : Application for Aircraft Hydraulic jacks
04/06/2010 1 Day Piezo Training 2010 269
Valve test bench
Flow meter
Pressure sensors
Output Input
Piezo
Valve
No leakage at 220 bars in closed position.
Piezo Actuators : Application for Aircraft Hydraulic jacks
04/06/2010 1 Day Piezo Training 2010 270
Valve resultsType Normally closedActuator APA500LPiston stroke 460 µmMaximal working pressure 100 barsMaxi. tested working freq. 400 Hz (power supply limitation)Max. theoretical working freq. 1000 HzOpen flow rate > 2.5 l/min.
Piezo Actuators : Application for Aircraft Hydraulic jacks
04/06/2010 1 Day Piezo Training 2010 271
Active Control of Fluids: Piezo Injectors for Automotive
short time responsecompact structurepotential for low cost
small piezo ceramic amountfew simple parts
Car Injectors based on an APA, according to
C.R.Fiat
04/06/2010 1 Day Piezo Training 2010 272
Pneumatic Valve Prototype (designed by Cedrat Technologies ) based on the APA100S (Courtesy of ENS)
Active Control of Fluids:Proportional Pneumatic Valves
04/06/2010 1 Day Piezo Training 2010 273
Piezo Actuators : Application for sound generation
Sound generator for urban water pipes localisationAPA230L + back mass + front membranepo < 10BarFr = 500 HzV < 10Vrms @Fru = 230µm @Frufront = 110µm @Fr
MADE Water Tracker sound emitter
Transducer based on APA230L
04/06/2010 1 Day Piezo Training 2010 274
Active Control of Vibrations
Complete close loop electronics including :a linear amplifier a sensor of displacement, speed, accel., force ...a controler : PI, PID, Feed forward, Force feed back ….
in order to drive & control the actuator(s)
04/06/2010 1 Day Piezo Training 2010 275
Active Control of Vibration: Damping of a truss by active tendons
Space Truss of ULB using an active tendon concept based on APA100Ms for active damping (Courtesy of Micromega Dynamics & ULB & ESA)
Truss vibration level after a shock excitation, without control (red curve)
& with control (blue curve)
04/06/2010 1 Day Piezo Training 2010 276
Active Control of Vibration : 6 dof Stewart Isolation platform
Hexapod based on 6 APA50S
Courtesy of ULB & Micromega Dynamics
04/06/2010 1 Day Piezo Training 2010 277
Active Control of Vibration : 6 dof Stewart Isolation platform
Experimental results
Courtesy of ULB & Micromega Dynamics
04/06/2010 1 Day Piezo Training 2010 278
R&D works supported by CNES / ApplicationsSpace Telescope mirror, Space fine instrumentsAircraft embedded cameras
New Objectives for the electronics : 2 functionsMicro-positioning of a loadIsolation of the load from micro-vibrations
Electronics for Piezo Actuators:Micro-Positioning & Damping
Frequency (Hz)40Hz5Hz
Micro vibration IsolationPosition
04/06/2010 1 Day Piezo Training 2010 279
Electronics for Piezo Actuators :Micro-Positioning & Damping
Set-up listAPA120ML actuator : load positioning&damping‘FB-LA Space’ electronics : driving the APAStrain Gage & Capacitive Sensors : position sensingAccelerometers : vibration sensingServo controller : closed loop controlLarge Magnetostrictive Actuator : Excitation
04/06/2010 1 Day Piezo Training 2010 280
Electronics for Piezo Actuators:Micro-Positioning & Damping
Set-up view
Excitator APA120ML Dummy load Electronics
04/06/2010 1 Day Piezo Training 2010 281
Electronics for Piezo Actuators :Micro-Positioning & Damping
Closed loop
Pdrift
Préf Piezoε
K(p)
F(p) A(p) D(p)
H(p)
K1(p)H1(p)F1(p)
D(p), the piezo+load transfer function,A(p), the power amplification transfer function,F(p), the position corrector function,H(p), the low pass filter transfer function,
K(p), the position sensor transfer function,K1(p), the vibration sensor transfer function,H1(p), the filter of the control loop,F1(p), the vibration corrector function
04/06/2010 1 Day Piezo Training 2010 282
Electronics for Piezo Actuators:Micro-Positioning & Damping
Measured performances-40dB/decade roll off, the cut off frequency close to 50Hz,the over shoot 5dB@50Hz,the maximum attenuation : 10 dB
-14-12
-10
-8
-6
-4-2
0
2
46
0 50 100 150 200
Frequency (Hz)
Atte
nuat
ion
(dB
)
04/06/2010 1 Day Piezo Training 2010 283
Active Control of Vibration: One axis flexure beam / Rossignol Ski
Control OFF Control ON Ski Rossignol
04/06/2010 1 Day Piezo Training 2010 284
Active Tool Control:Oval Piston Machining
Courtesy of Entech (SP)PPA80L-SG
04/06/2010 1 Day Piezo Training 2010 285
Courtesy of Entech (SP)
PPA80L + OEM LA75B inc. PI controler
C = 26 µF ; Imax = 1.2 A
Tool mass = 1 kg
Peak Amplitude vs frequency
Displacement = 70 µm @ 100 Hz
Active Tool Control:Oval Piston Machining
04/06/2010 1 Day Piezo Training 2010 286
Active Control of Vibrations : One axis tool controlin machining
Mechanical structure
Chatter vib.
Piezo actuator
Force sensor
Guiding membrane
Tool holder
Elastic actuator pre-stress
Tool caseActuated sleeve
VDI-3425interface
Tool interface
cutting
feed
passive
Piezo actuator
Force sensor
Guiding membrane
Tool holder
Elastic actuator pre-stress
Tool caseActuated sleeve
VDI-3425interface
Tool interface
cutting
feed
passivecutting
feed
passive
mag
nitu
de [m
/s2 ]
0 500 1000 1500
Ha/38251 © IFW
cutting force direction
passive force direction6
43
7
5
210
frequency [Hz]
mag
nitu
de [m
/s2 ]
0 500 1000 1500
Ha/38251 © IFW
cutting force direction
passive force direction6
43
7
5
210
6
43
7
5
210
frequency [Hz]
Cooperation IFW - Cedrat (ACTUATOR 2004)
04/06/2010 1 Day Piezo Training 2010 287
Active Control of Vibrations : One axis tool control in machining
Control by force feedback
forcesensor
actuator chargeamplif ier
Q
actuatoramplif ier
analogueintegrator
U
UU
Fd
Fp
Q
F
highpassfilter
~__+-
U
forcesensor
actuator chargeamplif ier
Q
actuatoramplif ier
analogueintegrator
U
UU
Fd
Fp
Q
F
highpassfilter
~__~__+-
U
04/06/2010 1 Day Piezo Training 2010 288
Active Control of Vibrations : One axis tool controlin machining
Control by force feedback
Mag
nitu
de g
/N [d
B]
Frequency [Hz]
Ha/38253 © IFW-80
-40
-70
-60
-50
-74
-66
-56
-46
0 1024500200 700
Active damping off
Active damping onMag
nitu
de g
/N [d
B]
Frequency [Hz]
Ha/38253 © IFW-80
-40
-70
-60
-50
-74
-66
-56
-46
0 1024500200 700
Active damping off
Active damping onIFW - Cedrat
04/06/2010 1 Day Piezo Training 2010 289
Active damping of Vibration of Rossignol Ski
Application : Launched Kilometer SkiVibration level of the Ski tip : 8cm pk-pkDesign configuration : APA120ML + pulling rod
Dynamic displacement divided : <120µm to the actuatorDynamic force transmitted < 1200N to the actuator
LK Ski of SKI Rossignol equipped with APA120ML for active damping
04/06/2010 1 Day Piezo Training 2010 290
Active damping of Vibration of Rossignol Ski
Application : Launched Kilometer SkiFEM analysis to get Eq circuit Matlab simulinkTest results on snow : 32bB damping / 1st modeCedrat design patented by Rossignol
04/06/2010 1 Day Piezo Training 2010 291
Other Machine Tools
PDP Glass cutting assistanceWire bondingLCD screen alignementChip testing on wafersActive damping on tools
APA100SCourtesy of Kammrath & Weiss
04/06/2010 1 Day Piezo Training 2010 292
Telecom: stretching fibre
Active Fibber Bragg Gratings for DWDMTunable Laser Optical switchFibber alignment
APA50S + FBG for laser tuning
04/06/2010 1 Day Piezo Training 2010 293
Electrical Power Generator
04/06/2010 1 Day Piezo Training 2010 294
Electrical Power Generator
04/06/2010 1 Day Piezo Training 2010 295
Electrical Power Generator
Basic configuration
04/06/2010 1 Day Piezo Training 2010 296
Electrical Power Generator
APA-based Proof-massAPA400M_MD + MassMesema project end user :
EADS, Eurocopter
Out power & Effciency accounting for the electronics
APA400M proof mass
04/06/2010 1 Day Piezo Training 2010 297
Electrical Power Generator
References Unit GPA60SM
Notespreliminary
datainput mechanical energy mJ 2Displacement µm pk-pk 11Output electrical energy mJ 0.1Load impedance kOhm 1.5Min. Voltage V 1.8Time to maintain the voltage ms 45
Courtesy of LEGRAND
Wireless switch based on APA60SM
04/06/2010 1 Day Piezo Training 2010 298
Synthesis: typology of applications of Piezo products
Position controlOptical control Shape controlDriving control Reduction of noise, vibration Vibration controlFluid control Generation of noise, vibration Energy harvesting