mechatronics o l u t i o n scompact - dynamic - precise

CEDRATTECHNOLOGIESInnovation in Mechatronics

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Products Catalogue Version 5.1 ﻿

TABLE OF CONTENTS
1. CEDRAT TECHNOLOGIES ACTUATOR SOLUTIONS

7

1.1. Introduction to piezo & magnetic actuators from Cedrat Technologies

7

1.2. Synthesis of Cedrat Technologies offer

8

1.3. Overview of Cedrat Technologies products & technologies

9

1.3.1. Parallel Pre-stressed Actuators PPA

10

1.3.2. Amplified Piezoelectric Actuators APA® 

10

1.3.3. Stepping Piezo Actuators SPA

10

1.3.4. Moving Iron Controllable Actuator MICA™

10

1.3.5. Bistable Linear Moving Magnet BLMM

11

1.3.6. Moving Coil Actuators MCA

11

1.3.7. Sensors solutions11

1.4. Cedrat Technologies services & facilities

12

1.4.1. Engineering services12

1.4.2. Production & lab’ capability13

1.4.3. Technical assistance & training

13

2. TUTORIAL

15

2.1. Tutorial on piezoelectric actuators

15

2.1.1. Introduction to piezoelectric materials

15

2.1.2. Characteristics of piezoelectric materials

16

2.1.3. Advantages & limitations of piezo actuators

16

2.1.4. Parallel Pre-stressed Actuators PPA

17

2.1.5. Amplified Piezoelectric Actuators APA 

18

2.1.6. Stepping Piezo Actuators SPA19

2.1.7. Static behaviour of piezoactive actuators

20

2.1.8. Dynamic behaviour of actuators (low level)

21

2.1.9. Limitations of piezoelectric actuators

22

2.1.10. Driving of piezoelectric actuators

25®

2.2. Tutorial on magnetic actuators

27

2.2.1. Introduction to magnetic actuators

27

2.2.2. Moving Coil Actuators MCA

28

2.2.3. Conventional moving iron actuators - Electromagnets

29

2.2.4. Moving Iron Controllable Actuators MICA™

30

2.2.5. Bistable Linear Moving Magnets actuators BLMM

30

2.2.6. Limited Angle Torque actuators LAT

32

2.2.7. Choosing voltage or current electrical driving principles

33

2.2.8. Electrical impedance adjustment

34

2.2.9. Resonant flexure bearing actuators

34

2.2.10. Electromechanical limits of actuators

37

2.2.11. Active & reactive electrical power

38

2.2.12. Magnetic actuators heat dissipation

40

2.2.13. Analysis of magnetic actuators with losses

41

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CEDRATTEC
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Innovation in Mechatronics

3. MARKETS & APPLICATIONS

43

3.1. Market overview43

3.2. Applications & functions classified by working conditions45

3.2.1. Applications operated under static conditions46

3.2.2. Applications operated under dynamic non-resonant conditions48

3.2.3. Applications operated under dynamic resonant conditions50

3.2.4. Applications operated under dynamic force conditions51

3.2.5. Applications operated under impulse conditions52

3.2.6. Applications operated under dynamic sensing conditions53

3.3. Additional technological solutions54

3.3.1. Hollow Parallel Prestressed Actuator HPPA

54

3.3.2. Extremely amplified actuators

54

3.3.3. Applications requiring a high stability in closed loop

55

3.3.4. Mechanically-damped Amplified Piezoelectric Actuators APA ®

4. PIEZO ACTUATORS

55

57

4.1. Selection guide57

4.1.1. Introduction

57

4.1.2. Mechanical interface options58

4.1.3. Standard options58

4.1.4. Specific versions58

4.2. Amplified Piezoelectric Actuators APA ®

4.2.1. APA uXS & XXS series
®

60
60

®

4.2.2. APA XS series

61

4.2.3. APA® S series

62

4.2.4. APA® SM series

63

4.2.5. APA M series

64

4.2.6. Super APA M series

65

4.2.7. APA® MML series

66®

4.2.8. APA ML series

67®

4.2.9. APA L series

68

4.2.10. APA® XL series

69

®

®

4.3. Multi-Layer Actuators MLA series

70

4.4. Parallel Pre-stressed Actuators PPA

71

4.4.1. PPA M series

71

4.4.2. PPA L series

72

4.4.3. PPA XL series

73

4.5. Customised piezo actuators

5. PIEZO MECHANISMS

74

77

5.1. Selection guide

77

5.2. X piezoelectric stages

78

5.3. XY piezoelectric stages

78

5.4. XYZ piezoelectric stages

78

5.5. Tilt Translator TT

79

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5.6. Double Tilt Translator DTT

79

5.7. Fast Piezo Shutters FPS200M, FPS400M & FPS900M

80

5.8. Fast Amplified Piezo Shutter FAPS400M

80

5.9. Customised piezo mechanisms

81

6. PIEZO MOTORS AND MOTORISED STAGES

83

6.1. Linear Stepping Piezo Actuator LSPA

84

6.2. Linear Stepping Piezo Stage LSPS

85

6.3. Modular Stepping Piezo Actuator MSPA

86

6.4. Rotary Stepping Piezo Actuators RSPA87

6.5. Fine Stepping Piezo Actuator FSPA

88

6.6. Customised piezo motor mechanisms

89

6.6.1. Rotary stage

89

6.6.2. Long stroke linear stage

89

6.6.3. Long stroke curved stage

89

6.6.4. 3 axis closed loop mechanism

89

6.6.5. Space FSPA

89

7. MAGNETIC ACTUATORS

91

7.1. Moving Iron Controllable Actuator MICA™

92

7.2. Bistable Linear Moving Magnet BLMM

95

7.3. Tunable proof mass actuators

96

7.4. Specific magnetic actuators

97

7.4.1. Moving Coil Actuators MCA

97

7.4.2. Extra flat MICA™ stages

97

7.4.3. Specific Electro-Magnet Actuator EMA98

7.4.4. Specific moving iron actuator

98

7.4.5. Asynchronous linear motor

99

7.4.6. Magnetic Fast Steering Mirror M-FSM

99

8. DRIVE ELECTRONICS & CONTROLLERS
8.1. Amplifiers & controllers for piezo actuators

101
102

8.1.1. OEM series

102

8.1.2. Powered rack mounted series

104

8.1.3. Linear voltage amplifiers

106

8.1.4. Switching voltage amplifiers

106

8.1.5. Two States Power Amplifier

109

8.1.6. Digital controllers

110

8.1.7. Customised amplifiers and controllers

111

8.2. Amplifier for magnetic actuators

112

8.2.1. OEM series

112

8.2.2. Customised amplifiers & controllers

115

8.3. Controller for piezo motors

116

8.3.1. Controller board for stepping piezo actuator

116

8.3.2. Customised controllers for piezo motor based mechanisms

117

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9. SENSORS & CONDITIONERS

121

9.1. Selection guide121

9.2. Strain gauges & associated conditioners

122

9.2.1. Strain gauge sensors122

9.2.2. Strain gauges conditioners

122

9.3. Eddy Current Sensors & associated conditioners

124

9.3.1. Eddy Current sensor Probes ECP

124

9.3.2. Eddy Current Probe conditioners ECS

126

9.4. Customised sensors’ solutions

128

9.4.1. Customised sensor’s integration

128

9.4.2. Customised magnetic sensors & detection systems

128

9.4.3. Non-Destructive Testing NDT & Structural Health Monitoring SHM

130

10. MECHATRONIC SOLUTIONS

133

10.1. Evaluation Pack EP120S

134

10.2. Educational kit ACV - Active Control of Vibrations

135

10.3. Piezo motor developer kits

136

10.3.1. LSPA30uXS piezo motor developer kit

136

10.3.2. LSPS35XS piezo motor developer kit

136

10.3.3. MSPA35XS piezo motor developer kit137

11. APPLICATION NOTES

139

11.1. Your own application selection guide139

11.2. Building a general piezoelectric actuator model

142

11.3. Positioning Control of Piezo Actuators

143

11.4. EPC: Enhanced Peak Current 

144

INDEX147

Products Catalogue Version 5.1 ﻿

5CEDRATTECHNOLOGIES
Innovation in Mechatronics

compact dynamic precise

For more information on this chapter,
please visit these pages:
www.cedrat-technologies.com
cedrat-tec.com/contacts/about-us
cedrat-tec.com/services

Products Catalogue Version 5.1 - Cedrat Technologies actuator solutions

1. CEDRAT TECHNOLOGIESACTUATOR SOLUTIONS
1.1. INTRODUCTION TO PIEZO & MAGNETICACTUATORS FROM CEDRAT TECHNOLOGIESCEDRAT TECHNOLOGIES (CTEC) has been constantly upgrading and enlarging its range ofactuators and related electronic solutions since the middle of the 90s. In order to keep pace with
its customers’ needs and demands for efficient and robust mechatronic systems, CTEC has beendeveloping Compact, Dynamic and Precise components through several families of products:• Piezo actuators (APA®, PPA & mechanisms) working in strain mode,• Piezo motors (SPA series) and stages (SPS series) working in stepping mode,• Controllable magnetic actuators (MICA™),• Bistable magnetic actuators (BLMM).
These actuators as well as the dedicated drivers, sensors and controllers are presented allalong the sections of this catalogue. These actuators coupled with the relevant drive, sensor
and controller offer a wide range of standard components and functions to build your own
mechatronic systems and applications. In order to satisfy specific requests and demanding
environments, CTEC can develop both customised components and mechatronic systems under
your technical specifications, from building blocks briefly described here below.
To offer its customers the “state of the art” of products, some new products are given with“preliminary data”, which means that the product has been designed but has not been tested
as much as requested by CTEC quality standards at the time of printing.

The technical information on this chapter is not contractualand can be changed without prior notice.

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CEDRATTECHNOLOGIES
Innovation in Mechatronics

compact dynamic precise

1.2. SYNTHESIS OF CEDRAT TECHNOLOGIES OFFER
All products from CEDRAT TECHNOLOGIES (CTEC) can be assembled to build a complete mechatronic system (Fig. 1.a).
CTEC offers a complete range of products, either standalone or OEM.
Note that mechanisms can produce larger stroke than the elementary actuators. All these electromechanical devices canbe driven and controlled with the appropriate electronics.

Fig. 1.a: Complete configuration: actuator, driver, sensor and control

Products Catalogue Version 5.1 - Cedrat Technologies actuator solutions

1.3. OVERVIEW OF CEDRAT TECHNOLOGIES PRODUCTS & TECHNOLOGIESCTEC’s standard linear actuators cover a range of free displacements from 10 μm to 10 mm and more (Fig. 1.b).
They have been designed in order to offer the largest possible stroke while keeping a reasonable size. The choice between
these different solutions should be made regarding the need in force, displacement and working frequency.

Fig. 1.b: CEDRAT TECHNOLOGIES range of products

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CEDRATTECHNOLOGIES
Innovation in Mechatronics

compact dynamic precise

1.3.1. PARALLEL PRE-STRESSED ACTUATORS PPA
PPA are solid-state linear actuators. They only use the expansion of
the active material, in 33-mode, to produce a useful displacement.
This displacement is proportional to the voltage within a 170 V range.
Typically, the actuator’s deformation is about 0.1% of its length (1 μm/mm), so their displacements are limited to about 100 μm. However, theforces are naturally high, easily higher than 1 kN.
Fig. 1.c: PPA40L

PPA use an external deformable frame to pre-stress the ceramics. PPA are
cheaper, more compact, and display a much better dynamic behaviour
than conventional direct piezo actuators.
More info on chapter 4.4, page 71.

1.3.2. AMPLIFIED PIEZOELECTRIC ACTUATORS APA®
APA® are solid-state long-stroke linear actuators (Fig. 1.d). They are basedon the expansion of the active material and on a mechanism to amplify
the displacement. This amplified displacement is proportional to thevoltage within a 170 V range. The advantages of APA® are their relatively
large displacements combined with their high forces and compact size
along the active axis. It leads to a deformation of 1% (10 μm/mm) or
more. Therefore, their stroke may achieve up to 2 mm.
Fig. 1.d: APA120ML

Thanks to their compactness, APA® can be stacked in series to reachlonger strokes. Since APA® are robust, they can also be used in dynamic
applications, including in resonant devices.
More info on chapter 4.2, page 60.

1.3.3. STEPPING PIEZO ACTUATORS SPA

Fig. 1.e: LSPS35XSSPA are another way to use APA®. SPA are long-stroke piezoelectricmotors for micro/nano positioning applications benefiting from the
APA® heritage. They operate by accumulation of small steps. Between
each step the actuator is locked in position. It can also be operated ina deformation mode for a fine adjustment around a step position. In
this mode the resolution is nanometric. SPA concept leads to different
product families (LSPA, RSPA, LSPS...) which differ by their motion
type (linear or rotating) and by the possible addition of a guiding like
LSPA35XS stage.
More info on chapter 6, page 83.

1.3.4. MOVING IRON CONTROLLABLEACTUATOR MICA™
For applications where long strokes and highly dynamic actuators are
required, CEDRAT TECHNOLOGIES (CTEC) develops magnetic actuators,
the MICA™. With strokes up to 10 mm, forces up to 500 N, MICA™ are
perfectly complementary products to our well-known piezoelectric offer.

Products Catalogue Version 5.1 - Cedrat Technologies actuator solutions

11

MICA™ are robust, long lasting and powerful controllable actuators, witha force proportional to the current and can be used either for highfrequencies or static applications. They come with an embedded position
sensor and convenient mechanical interface for an easy integration.
They are the preferred option for high force continuous nonstop
operations that require efficient heat sinking, and long lifetime fatigue
requirements.
More info on chapter 7.1, page 92.
Fig. 1.f: MICA500L.

1.3.5. BISTABLE LINEAR MOVING MAGNET BLMM
BLMM actuators, are bi-stable actuators providing two locked positionsat rest, without electrical power. Electrical power is required only to switchfrom one position to the other one, which is achieved with a very fastswitching time, as per required in latching operations. Such actuatorspresent high miniaturisation capabilities, as well as a high degree of
response time performance tuning.
More info on chapter 7.2, page 95.

1.3.6. MOVING COIL ACTUATORS MCA
MCCA are the actuators having the best linearity performance achievable
for very long stroke requirements beyond 10 mm. MCCA are the best
controllable actuator reference for fine precision control and linearity,
and are the preferred option for large motions in translation or rotation.

Fig. 1.g: ECS75-TS board

Compared to other technologies such as moving magnets and moving
iron, moving coil actuators present some limitations with regard to heatdissipation, coil temperature, and flying electrical connection reliability.

1.3.7. SENSORS SOLUTIONSCTEC has developed a deep know-how in strain gauge integration tocontrol the displacement of piezo actuators. Demanding requirements,
such as long term stability or vacuum environment compatibility can beachieved by this technology.
Also CTEC offers magnetic position sensors which provide a contactless
distance measurement. Different technologies and topologies areproposed, to cover a wide range of applications, from nanometric tometric range. Some of these sensors can be integrated as standard to
CTEC actuators and mechanisms in order to provide a position or state(open/close) information. For instance for PPA and APA® piezo actuators,
strain gauges or Eddy Current Probes can be used depending on the
precision required.
More info on chapter 9, page 121.

PRACTICAL APPLICATION: LONG TERMSTABILITY MEASUREMENT
Some applications require amechanism capable of nanometricresolution position tuning, and withthe ability to maintain perfectly thisposition for a long time (more thanseveral days). CTEC has managed todemonstrate the ability of a piezomechanism with integrated strain
gages sensors to achieve nanometricposition stability. This requires a
specific set-up, particularly to stabilise
the temperature variations below±0.15°C to measure displacements as
small as one nanometre.

compact dynamic precise

CEDRATTEC
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1.4. CEDRAT TECHNOLOGIES SERVICES & FACILITIESCEDRAT TECHNOLOGIES (CTEC) heritage in space industry
makes us used to work on complex problems in deep
interaction with our customers.

From specific interface to dedicated design, throughtesting, system integration and assistance, our sales
engineers help you all along your project.

1.4.1. ENGINEERING SERVICESCTEC develops custom mechanisms for your actuating or
sensing function. We can assist you with:• Consulting and feasibility studies• Modelling, design work

CTEC performs step-by-step developments in partnershipwith its customers. Expertise, optimisation, design,
prototyping, testing, manufacturing, any of these phases
can be addressed to help our customers reaching theirdemanding application targets.
Several new mechatronics technologies
are being developed or are being
improved: please do not hesitate to takea look at our website for any updated
information.

• Prototyping and testing• Industrial projects leading to aturn-key solution• R&D collaborative projects fundedby the European Commission(H2020 projects) or otherframeworks (Eureka, national
projects)• Manufacturing for the account ofcustomers under QA (ECSS, MILSTD, ANSI/IPC3)

Fig. 1.h: FEA of piezoelectric FSM• Technology transfers (Licensing)• IP management and patent support
CTEC’s know-how, facilities and experience allow its teamto efficiently develop new actuators, sensors, mechanisms
or high level mechatronic system.

OUR SCOPE OF EXPERTISE:- Electromagnetism- Piezoelectric- Solid and fluid mechanics- Thermal aspects- Power electronics- Controls- System integration

In terms of service through a project,
CTEC can also adapt an existing productor technology to new environmental
conditions: thermal range, resistance toparticular vibration spectrum, lifetime…
as found in aerospace, medical, oilindustries…

Some examples of applications are given in chapter 3,
page 43 and at the end of chapter 4, page 57 tochapter 7, page 91.

Products Catalogue Version 5.1 - Cedrat Technologies actuator solutions

1.4.2. PRODUCTION & LAB’ CAPABILITY

Fig. 1.i: Production bench

CTEC makes thousands actuators and mechanisms ayear for its customers. Integration and measurement of
all mechatronic products are performed in our facilities inFrance (Meylan).
We can apply several quality standards (ECSS, MIL-STD,
ANSI/IPC3).
Our production team routinely integrates batches up to
several hundreds of pieces, using an adapted surface of
400 m² and an ISO7 or ISO5 clean room to comply withapplications in ultra high vacuum (UHV) or integrating
optics.
CTEC makes use of specialised test equipments for
precise, high frequency displacement and environment
testing of active devices:• HP Impedance analyser used for the measurement ofadmittance curve, resonance and equivalent circuits,• Several inter ferometres, vibrometres andautocollimators used to measure the actuator’s main
displacement & speed as well as parasitic displacementwith high precision,• Climatic and thermal vacuum chambers allow theanalysis of thermal behaviour and/or of the effects ofprimary or ultra vacuum (such as Paschen effect).
Additionally, we work in collaboration with specialised
laboratories and industries to answer to more specificneeds, such as electrodynamic shaker or EMC
measurement.

1.4.3. TECHNICAL ASSISTANCE &TRAINING

Fig. 1.j: Training at CTECCTEC can help you to turn your ideas into innovative
projects. From training to dedicated assistance, we
respond precisely to the way you wish.
Training are performed by CTEC’s experts, using theirexperience in mechatronics or detection components
and systems. They cover the fields of actuators, motors,
transducers, sensors based on electric, magnetic,
piezoelectric, magnetostrictive, MRF, ultrasonic effects ormaterials, electronics driving and control as well as theirapplications.
Detailed program and catalogue:
cedrat-tec.com/services/training/technology-training

For more information about CTEC services, please visit:
cedrat-tec.com/services

13

CEDRATTECHNOLOGIES
Innovation in Mechatronics

compact dynamic precise

For more information on this chapter,
please visit these pages:
cedrat-tec.com/products/actuators
cedrat-tec.com/products/magnetic-actuators

Products Catalogue Version 5.1 - Tutorial

2. TUTORIAL
2.1. TUTORIAL ON PIEZOELECTRIC ACTUATORS
2.1.1. INTRODUCTION TO PIEZOELECTRIC MATERIALSIn 1880 the Curie brothers first examined the piezoelectric effect on crystal materials, which has
the ability to produce electrical charges in response to externally applied forces. This is called
the direct effect. This effect is reciprocal; meaning that the piezoelectric material changes its
dimensions under applied electrical charges.
In 1922 Langevin proposed the first actuator based on crystal materials. To enhance its
efficiency, this actuator was driven at resonance. The discovery of piezoelectricity in PZT (leadzirconate titanate) in the late 1960’s increased the number of applications for industrial use.
Piezoelectric transducers based on bulk PZT rings have been developed for sonar, ultrasonicwelding, ultrasonic cleaning applications, etc. Sensor technology using piezoelectric ceramics(pressure or force sensors, hydrophones, accelerometers...) has matured since then. Basedon piezoelectric bulk PZT rings, actuators for positioning purposes have also been studied.
However, to obtain the deformation level required for this type of applications, it is necessary
to use high input voltages. For instance, 0.5 mm thick PZT rings require an excitation voltage
of approximately one thousand volts, which is clearly too high for several practical purposes.
Multilayer Actuators (MLA), derived from the high capacitor technology, were introduced on themarket in 1988 to circumvent the previous limitations. Because MLA are easy to operate, they
have been increasingly used in various applications. The required excitation voltage of 150 Voltsor less is well adapted to modern electronics.
These new materials are used by CEDRAT TECHNOLOGIES (CTEC) to build high energy density
actuators and other devices, which are available either as standard or customised products, andwhich can be supplied with the dedicated electronics.

The technical information on this chapter is not contractualand can be changed without prior notice.

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CEDRATTECHNOLOGIES
Innovation in Mechatronics

compact dynamic precise

2.1.2. CHARACTERISTICS OFPIEZOELECTRIC MATERIALS

difficulty of depolarising them. Table 2.a lists some typical
properties of active materials.

Piezoelectric materials are crystalline solids whose
asymmetric structures create an electric dipole momentin the crystal lattice, which is sensitive to both the elasticstrain and applied electrical field.
PZT materials are ferroelectric materials under the Curie
temperature: the poling process gives the material its
remanent polarization. During the poling operation, thematerial is subjected to a high electric field at the Curie
temperature. If the material is subjected to a greatertemperature than its Curie temperature, it is no longer
piezoelectric. It can be epolarised to be piezoelectric again
under certain conditions.

Actuators made from single crystals or Electro-Active
Polymer’s (EAP) are still in their infancy, but may lead to
new actuators in the future: their strain capabilities up to
respectively 3 % and 300 % are outstanding.

Stresses and strains are related to each other by theYoung’s modulus of the ceramic. In addition, a stressgenerates an electric field through the inverse piezoelectriceffect. Since the ceramic is a dielectric medium, theelectrical displacement is related to the electric field.
These relationships can be combined in several sets ofequations.

Magnetostrictive materials like Terfenol-D are also studied
at CEDRAT TECHNOLOGIES (CTEC). They expand whensubjected to a magnetic field. Despite the losses occurringin the excitation coil, actuators based on this material may
be well suited for very low-voltage or power applications.
Customised actuators and transducers based on thismaterial can be built by CTEC upon request.

For example:

Electrostrictive materials, such as PMN-PT also exist in
multilayer. This material displays a low hysteresis (<2 %),but is much more temperature-dependent than PZTmaterial.

𝐸𝐸
𝑆𝑆𝛼𝛼 = 𝑠𝑠𝛼𝛼𝛼𝛼
𝑇𝑇𝛽𝛽 + 𝑑𝑑𝑛𝑛𝛼𝛼 𝐸𝐸𝑛𝑛

𝑇𝑇
𝐷𝐷𝑚𝑚 = 𝑑𝑑𝑚𝑚𝑚𝑚 𝑇𝑇𝛽𝛽 + 𝜀𝜀𝑚𝑚𝑛𝑛
𝐸𝐸𝑛𝑛

α, β = 1, ..., 6
m, n = 1, 2, 3
S: Strain
T: Stress
D: Induction
E: FieldsE: Compliances at constant field
d: Piezoelectric strains per unit of field
εT: Permittivity at constant stress

The previous equations can be combined to define theelectro-mechanical coupling coefficient, which can beseen as the ratio of the convertible energy to the totalenergy supplied to the piezoelectric actuator. Practicalvalues of the material’s coupling coefficient can be higher
than 50 %, but in actuators, or in resonant transducers,
the effective coupling factors keff are usually lower. The
electromechanical coupling coefficient should not be
regarded as the actuator’s efficiency. The set of equations
shown above does not take any loss into account.
Commercial piezoelectric ceramics can be classified as
soft-type or hard-type materials based on the ease or the

Fig. 2.a: View of a piezo ceramic stack (MLA)

2.1.3. ADVANTAGES & LIMITATIONSOF PIEZO ACTUATORS• Their solid-state design with no rolling parts, so thatthey are not subjected to wear
• Unlimited resolution, making them ideal for nanopositioning• Low power consumption• Low heat dissipation• High force / mass ratio, allowing their fast responsetime• Possible non-magnetic option• Possible operation in ultra high vacuum• Possible operation in cryogenic temperatures• Limited displacements range (below 2 mm)• Limited to temperatures below 100°C (or 150°C in
H.T. option), although some progress is being made for
automotive applications

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2.1.4. PARALLEL PRESTRESSED ACTUATORS PPAfactor of this structure is high, generally higher than 50 %,as well as the elastic energy per unit of mass.

Direct piezo actuators are the most simple type of
actuators: they consist of a stack of pre-stressed piezo
ceramic. CTEC configuration consists in pre-stressing the
MLA stack through an external elastic frame, leading to a
Parallel Pre-stressed Actuator PPA.

Because the pre-stress level of PPA is well controlled, they
display a good dynamic behaviour and can be operated atresonance.
The displacement is roughly proportional to the voltage,
from -20 to 150 V, which can be produced with special
power electronics. The relation between the displacement
and the voltage is not exactly linear because of thehysteresis of the active material. This effect can be wellcontrolled with the appropriate feedback electronics,
which linearise the system’s behaviour.
As the strain of present piezo materials is limited to 0.12 %,the induced displacement is necessarily small, even withvery long actuators. That is the reason why there is no
direct piezo actuator offering 200 µm of stroke available
on the market.

Fig. 2.b: View of PPA

PPA use the expansion of the active material, to produce a
useful pushing displacement. As most of the energy strain
is stored into the active material, the effective coupling

MATERIALS

Due to non active pieces (end parts, prestress mechanism),
the deformation of the actuator is smaller than that of thematerial itself, leading to values from 0.08 % to 0.10 %(0.8 to 1 μm/mm) in the PPA80L. Thus, a 100 mm long PPA
can reach about 80 to 100 μm. The longest PPA can hardly
be longer than 200 mm because of the risks of breaking
in buckling. That is the reason why there is no direct piezo
actuator 200 μm of stroke available on the market (in thiscase Amplified Piezoelectric Actuator APA ® offer analternative solution).

CONTROL FIELD
E ELECTRIC
H MAGNETIC

YOUNG’S
MODULUS AT
CONSTANT FIELD(GPA)MECHANICALQUALITY FACTOR(QM)

ELECTROMECHANICALCOUPLING
COEFFICIENT
K33 (%)QUASISTATICMAXIMUM STRAIN
(PPM)

E
E
E
E
E

74
72
66
48
10

1 000
600
500
75
-

64
67
70
75
90

+/- 110+/- 150+/- 300
3 000

E
E

45
62

25 - 50
200 - 500

70
60

1 250
800

E
E

1
1

20
-

30
-

1 000
3 000000H

25

10 - 2070

1 600> Bulk piezoelectric

PZT-8
PZT-7
PZT-4
PZT-5
Single-crystals (PZN-PT)> Multilayered piezoelectrics (MLA)

Soft-typeHard-type> Electroactive polymers (EAP)

PVDF
Dielectric elastomers> Magnetostrictives

Terfenol-D

Table 2.a Properties of piezoactive materials

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2.1.5. AMPLIFIED PIEZOELECTRIC ACTUATORS APA®
The displacement limitation of Parallel Prestressed Actuators PPA can beovercome thanks to an elastic mechanical amplifier. Various designs,
most of them using flexural hinge, have been proposed in the past.
Stresses become very high in the hinges during actuation, resulting in
fatigue effects.

Fig. 2.c: View of an APA120S

Amplified Piezoelectric Actuators APA® are based on a shell without any
hinges. High displacements of APA® combined with high forces show thatthese actuators achieve displacement ampliﬁcations of 2 to 20 and havea good mechanical efficiency. Thanks to this ampliﬁcation and to theirshape ratio, they can achieve deformations from 1 % to 10 %. Note that
their deformation for a positive voltage is a contraction, meaning that
APA® are pulling actuators.
For example, at 150 V, the APA400M produces free displacements up
to 400 μm and blocked forces up to 38 N along its 14.3 mm short axis.
It corresponds to a deformation of 2.8 % along the short (active) axis.
This large deformation can also be found on large APA®: the APA2000L
produces free displacements up to 2000 μm and blocked forces up to
66 N, along its short axis, which is about 27 mm height, meaning 7.4 %deformation.
APA® present the following features:

Fig. 2.d: Finite element computation of an APA®
Dotted lines: Structure at rest
Full lines: Structure deformed by the piezoelectriceffect(Atila FEM result)• The actuators are small and compact relative to their strokes,• The displacement magnification and the stiffness are functions of theeccentricity of the shell,• It can be operated in a wide range of frequency including theresonance frequency,• The bending behaviour of the shell under the piezoelectric actuation
allows an acceptable distribution of stresses in the amplifier• Bending and / or twisting moments can be exerted (to a certain extent)on the shell, which prevents the MLA from breaking. From this specificpoint of view, APA® are considered to be more robust than PPA.

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2.1.6. STEPPING PIEZO ACTUATORS SPA
Stepping Piezoelectric Actuators SPA are new long-stroke piezoelectricmotors for micro/nano positioning applications beneﬁting from the APA®
heritage. The SPA relies on a simple design: an APA®, a front mass, aclamp and a rod. They operate by accumulation of small steps by stickslip (step mode M1). Between each step the actuator is locked in position.
When the long stroke is performed, it can also be operated in a
deformation mode (M2) for a ﬁne adjustment In this case, the stroke is
proportional to the applied voltage, which leads to a nanometre resolution
and a high bandwidth.
To summarise, SPA offers:• A stepping mode producing strokes of several mm,• A blocking at rest in any position (locking without power supply),leading to a high stiffness,• A nano positioning resolution all along the stroke,
The SPA can be driven by a one-channel CEDRAT TECHNOLOGIES linear
amplifier, SPC45 (See chapter §8. Drive Electronics & Controllers, page
101).
Many SPA can be defined starting from the standard range of APA®. SPA
find applications as micro positioning, locking mechanisms. They can be
non-magnetic and/or vacuum compatible.

Fig. 2.e: View of LSPA

The SPA concept leads to different product families:• LSPA: Linear Stepping Piezo Actuators• RSPA: Rotating Stepping Piezo Actuators• LSPS: Linear Stepping Piezo Stages, which are based on a LSPA andan additional linear guiding for removing transverse parasitic motion,• MSPA: Modular Stepping Piezo Actuators, which provide a convenient
way for integrating an LSPA in an already guided application,• FSPA: Fine Stepping Piezo Actuators, which is an original variation of
the LSPA that allows sub-micrometric stepping resolution combinedwith large forces.
All these products can perform in harsh environment:• Wide temperature range (including cryogenic):
- 200°C to + 70°C (70 K to 343 K)• Vacuum• External vibrations and shocks

Fig. 2.f: View of RSPA

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2.1.7. STATIC BEHAVIOUR OF PIEZOACTIVE ACTUATORSThis section gives some guidelines to choose the best
Parallel Prestressed Actuator PPA or Amplified Piezoelectric
Actuator APA® for quasi-static applications.
Two parameters define the actuator: the stroke ΔU0 (defined
as maximum displacement) and the blocked force F0 (maxforce at max voltage with no displacement).

If a constant load Fext (i.e. weight) is applied (smaller thanthe blocked force), it does not affect the stroke of thepiezoelectric actuator, but only results in a shift of the
maximum voltage position to a distance ΔL:∆𝐿𝐿𝐿𝐿 =

With a stiffness:and the force factor:

𝐹𝐹0
𝐾𝐾 =
∆𝑈𝑈0

𝑁𝑁 =

𝐹𝐹0
𝑉𝑉𝑚𝑚𝑚𝑚𝑚𝑚with Vmax, the higher voltage value allowed for the actuator.

And the maximum displacement in this situation becomes(see Fig. 2.h):∆𝑈𝑈𝑈𝑈0 − ∆𝐿𝐿𝐿𝐿
A very different situation occurs when the piezoelectric
actuator acts against a spring with a stiffness Kt (see Fig.
2.i).
The stroke becomes:

In most cases, the displacement ΔU is the first interest, it
is controlled by a voltage input V as follows:• Simple case: If there is no load and no external force on
the actuator, we can talk of free displacement:

𝑁𝑁𝑁𝑁𝑉𝑉𝑉𝑉∆𝑈𝑈𝑈𝑈(𝑉𝑉𝑉𝑉) =𝐾𝐾𝐾𝐾

when V=Vmax by definition ΔU(Vmax)= ΔU0 :𝑁𝑁𝑁𝑁𝑚𝑚𝑚𝑚𝑚𝑚 𝐹𝐹0=
𝐾𝐾
𝐾𝐾• Extended case: If there is a load on the actuator, when
we apply a voltage, a force F is generated on the load.
The resulting displacement will be:∆𝑈𝑈𝑈𝑈(𝑉𝑉𝑉𝑉) =𝑁𝑁𝑁𝑁𝑉𝑉𝑉𝑉 − 𝐹𝐹𝐹𝐹
𝐾𝐾𝐾𝐾

when the generated force F reaches F0, with V=Vmax,
it is clear that the maximum possible displacement
ΔU(Vmax) becomes 0. (See Fig. 2.g)

It means that the actuator cannot provide both the
maximum displacement and the maximum force, but asingle working point along the characteristic curve isdefined.

𝐹𝐹𝐹𝐹𝑒𝑒𝑒𝑒𝑒𝑒𝑒𝑒𝑒𝑒𝑒𝑒
𝐾𝐾𝐾𝐾∆𝑈𝑈𝑈𝑈 =
that gives:

𝑁𝑁𝑁𝑁𝑁𝑁𝑁𝑁 − 𝐾𝐾𝐾𝐾𝑡𝑡𝑡𝑡 ∆𝑈𝑈𝑈𝑈𝐾𝐾𝐾𝐾∆𝑈𝑈𝑈𝑈 = 𝑉𝑉𝑉𝑉𝑁𝑁𝑁𝑁𝐾𝐾𝐾𝐾 + 𝐾𝐾𝐾𝐾𝑡𝑡𝑡𝑡

And with the maximum voltage V=Vmax:∆𝑈𝑈𝑈𝑈 = ∆𝑈𝑈𝑈𝑈0𝐾𝐾𝐾𝐾𝐾𝐾𝐾𝐾 + 𝐾𝐾𝐾𝐾𝑡𝑡𝑡𝑡

Piezoactive actuators can be mechanically arranged inseries and/or in parallel. In the first case, displacements
are added and the force stays constant, while in the latter,the forces are added and the displacement remains thesame (see Fig. 2.j and Fig. 2.k).

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Products Catalogue Version 5.1 - Tutorial

2.1.8. DYNAMIC BEHAVIOUR OF
ACTUATORS (LOW LEVEL)
Which is the effect of electromechanical resonance on actuators?
If either the applied voltage or the external force varies with the time, thedisplacement still follows the excitations until dynamic behaviours
appear. The previous relationships remain valid in the quasi-static
bandwidth, which is limited by about one third of the resonancefrequency. If the actuator is unloaded, the resonant frequency is:

𝑓𝑓𝑓𝑓𝑟𝑟𝑟𝑟 =Fig. 2.g: Load characteristics of a piezoelectric actuator

1 𝐾𝐾𝐾𝐾�
2𝜋𝜋𝜋𝜋 𝑚𝑚𝑚𝑚

where m is the effective mass of the piezoelectric actuator. If the actuatoris loaded with an additional mass M, the resonance frequency fr thenbecomes:

𝑓𝑓𝑓𝑓𝑟𝑟𝑟𝑟 =

1
𝐾𝐾𝐾𝐾
�
2𝜋𝜋𝜋𝜋 𝑀𝑀𝑀𝑀 + 𝑚𝑚𝑚𝑚

The resonance frequency is also affected by external masses, spring
constants or damping effects.

Fig. 2.h: Position shift and load characteristicsof the actuator under a constant force

Dynamic operations are more complex because of the acceleration
acting on the piezoelectric actuator. Displacements (and consequently
stresses) can become very high.
At resonance, considering a constant voltage amplitude, they are
magnified by the mechanical quality factor Qm:∆𝑈𝑈0 = 𝑄𝑄𝑚𝑚

𝑁𝑁𝑁𝑁
𝐾𝐾

Fig. 2.i: Load characteristics undera spring with a stiffness kt.

The values of the Qm factor depend on many parameters coming bothfrom the actuator and the load. Typical values are in the range of 20 (highlevel) to 200 (low level) under free condition. They decrease in case ofresistive load (load exhibiting damping or energy radiation).
The settling time ts of the actuator is limited by the resonance frequency
fr:𝑡𝑡𝑡𝑡𝑠𝑠𝑠𝑠 ≈1
𝑓𝑓𝑓𝑓𝑟𝑟𝑟𝑟

Fig. 2.j: Series arrangements of APA®

In practical situations, the settling time of the actuator can be limited by
the charging time value of the electronics.
Note: The use of piezo actuators under dynamic conditions requires a careful
design and a lot of experience, because of the mechanical breaking risks.

Please do not hesitate to contact CEDRAT TECHNOLOGIES (CTEC) for
design and tests or to use CTEC CADs for preliminary analysis.

Fig. 2.k: Parallel arrangements of APA®

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2.1.9. LIMITATIONS OF PIEZOELECTRIC ACTUATORS
Piezoelectric actuators have several limitations that must
be taken into account in order to properly design theapplications. These limits are electrical, mechanical andthermal. The impact of these limits depends a lot on thefrequency region the actuators are used in (see Table 2.b).
These frequency regions are governed by the requested
function and applications.

ELECTRICAL LIMITS
The maximum voltage range is limited between -20 V+150 V. Out of this range, the piezo ceramic will be either
reversed in polarisation or electrically breakdown.
In static operations (S region), their lifetime is mainly
limited by the combination of DC voltage and humidity,
which penetrates through the external insulation layer andleads to an increase in current leakage. A larger current
leakage can lead to an electrical breakdown.
In dynamic strain non-resonant operation (DS region),
electrical limits may be encountered. Because of thecapacitive nature of piezo actuators, the higher thefrequency is, the higher the current is (see chapter 2.1.10,
page 27). This current need may reach the power amplifier
limits. To solve this problem CEDRAT TECHNOLOGIES(CTEC) develops high power linear and switching amplifiers.

MECHANICAL LIMITS

Examples of impacts of electric or mechanical limits on an
actuator’s capabilities:
The advantage of a high pre-stress is shown with the
APA120ML example under blocked-free conditions, loadedwith a 180 gr mass.
Note: The blocked-free condition means that one interface isfixed to a rigid body and the other interface of the actuator isfree to move the load. The free-free condition is where the twointerfaces of the actuator are free to move.

This offers a static stroke of 130 µm @ 170 V, so 0.76 µm/V.
Its blocked force is 1400N so 8.2 N/V. Its loaded resonancefrequency is 1 kHz. The graphs of Fig. 2.l show the actuator
response in harmonic analysis (sine excitation) and the
4 frequency regions. Thanks to the nominal high pre-stressof the APA120ML, the maximal dynamic peak force canreach 700 N (Fig. 2.m).
Thus the maximal dynamic stroke below resonance (DSregion) is higher than its maximal static stroke, while thestroke at resonance (R region) is similar to the static stroke(Fig. 2.n and Fig. 2.o). It gives a very large bandwidth fordisplacement generation. Dynamic forces above
resonance (DF region) can reach the blocked force. All
these dynamic properties are important for non-resonant
dynamic applications such as forced vibration generationor active damping, as well as for resonant applications
such as vibration generation at resonance.

In dynamic operations, especially in resonance region(R), the piezo actuator mechanical stress limits may be
encountered. To avoid tensile forces during dynamic
operation a well defined mechanical pre-stress is appliedon all the piezo actuators from CTEC.
The level of pre-stress is responsible of the force limit (0peak), or max dynamic peak force for the limitation of theactuator’s stroke (or its vibration amplitude).
REF

FREQUENCY REGIONBANDWIDTH DEFINITIONS

Static & quasistatic

From 0 to Fr/3

DS

Dynamic Strain

Between Fr/3 and resonance region

R

Resonance

3 dB-bandwidth around mechanical resonance frequency Fr

DF

Dynamic Force

Frequency above resonance region

I

Impulse (S + DS + R + DF)

Whole frequency spectrum

Table 2.b Different methods to use piezoelectric actuators

23

Products Catalogue Version 5.1 - Tutorial

For the same reason, the APA120ML can survive large
external vibrations and has successfully passed spacequalifications. To improve even more the ability to generate
or withstand dynamic movements in APA®, CTEC proposes

If a 10 times lower pre-stress were applied on the
APA120ML, the maximal dynamic peak force (in DS region)
could only reach 70N and so the maximal dynamic strokeat resonance (R) and below resonance would be much
Max. Force produced on the load

[N]

[V]
90

600,0

80
500,0

70
60

400,0

Mod(Fm) [N]

V [V]
50

300,0

40
30

200,0

20
100,0

10
0,0
0,0000Fig. 2.l: APA120ML in blocked-free conditions, loaded with a massof 180 gr: Displacement per volt versus frequency (See Table 2.b)0,20000,4000Pk-Pk displacement [µm]V_a [V]

200,0

1,600001,80002,0000

[A]
10,00

160

80

9,00

140

70

100
80

8,00
7,00

60

6,00
50

V_a [V]

5,00

Mod(I) [A]

40
4,00

100,0

50,0

0,0
0,00000,50001,0000Frequency [kHz]1,5000

60

30

40

20

20

10

0
2,000000,0000

3,00
2,00
1,00

0,20000,4000Note: below resonance, the displacement can be higher than atresonance, but the needed current is high, which may reach thepower limit of the electric amplifier.

140,0

V_a [V]

180

90

160

80

140

70

120

100,0

100

80,0

80

60,0

Pk-Pk Voltage [V]Mod_a(u) [µm]

60

40,0

40

20,0

20
1,00
Frequency [kHz]1,50

1,20000
2,00© Cedrat Technologies - COMPACT v5.11

Fig. 2.p: Modified APA120ML with a low pre-stress(90 % less than nominal) under blocked-free conditions,loaded with a mass of 180 gr: Maximal displacement
and maximal applicable voltage versus frequency.

1,40001,60001,80000,00
2,0000© Cedrat Technologies - COMPACT v5.11

smaller than its maximal static stroke (Fig. 2.p and Fig.
2.q).

Voltage & current for max displacement

[V]

120,0

1,0000Fig. 2.o: Requested peak voltage and peak current
to reach the displacement of Fig. 2.oMaximum Peak-to-Peak displacement & required Pk-to-Pk voltage
160,0

0,50

0,8000Frequency [kHz]solutions such as the Parallel Pre-stress Actuator PPA.

0,0
0,00

0,6000© Cedrat Technologies - COMPACT v5.11

Fig. 2.n: APA120ML in blocked-free condition, loadedwith a mass of 180 gr: Maximal displacement andmaximal applicable voltage versus frequency.

Pk-Pk displacement [µm]1,4000

90

120

150,0

1,2000180

Pk-Pk Voltage [V]Mod_a(u) [µm]1,0000

Voltage & current for max displacement

[V]

250,0

0,8000Fig. 2.m: APA120ML in blocked-free conditions, loadedwith a mass of 180 gr : Maximal forces vs frequency

Maximum Peak-to-Peak displacement & required Pk-to-Pk voltage
300,00,6000

[A]
3,50

3,00

2,50
60

50

V_a [V]

2,00

Mod(I) [A]

40

1,50

30
1,00
20
0,50

10

0
0,00000,20000,40000,60000,80001,00001,2000Frequency [kHz]1,40001,60001,80000,00
2,0000© Cedrat Technologies - COMPACT v5.11

Fig. 2.q: Requested peak voltage and peak current
to reach the displacement of Fig. 2.p

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Note also that APA ® with large amplification as the
APA900M have reduced pre-stress. That is why theirmaximal dynamic stroke in DS an R region is lower thantheir static stroke in S region, even much below resonance.
It limits their application to quasi-static conditions.
Therefore an APA200M can produce more displacement
at 100 Hz than an APA900M, although he an APA200M
static stroke is smaller (Fig. 2.r and Fig. 2.s).
Impulse applications found for example in injectors
and shutters are the most complex cases regarding an
actuator’s limits. In these applications, a step excitation
signal is typically used. This causes overshoots whichclearly excite resonance and can break the actuator.
Impulse response is due to a transient excitation signal.
It can be analysed as a spectrum of frequencies by
Fourier Transform. This signal spectrum can be multipliedwith the above transfer functions to get the actuator’s
response. Thus an impulse excitation uses the actuator
under dynamic conditions combining resonance and nonresonance frequency regions (DS, R, DF), which generates
a lot of stresses in the actuator. For this reason, high-prestressed actuators are preferable to get a long life time
under Impulse strain conditions. In safety preloading
conditions the life time of CEDRAT TECHNOLOGIES (CTEC)
piezo actuators is higher than 10 billion cycles.

THERMAL LIMITSDue to the dielectric and mechanical losses, thepiezoelectric actuator warms up under continuous
excitation. Losses are mainly non-linear and depend on
the excitation frequency, the voltage amplitude and thehumidity level. To avoid a depoling effect of the ceramic, thetemperature in the actuator should be monitored to ensurethat it stays well below the ceramic’s Curie temperature.
So the typical temperatures range from -40°C to +80°C.
As a consequence, the duty cycle of a piezoelectric actuatorin dynamic operation is limited by its thermal behaviour.
For instance, to maintain a constant temperature on the
APA60SM actuator, the duty cycle should be reduced
or a forced convection should be applied as the driving
frequency increases. There are currently a lot of researches
on materials that aim at producing MLA displaying higher
working temperatures (up to 200°C). Upon request, CTEC
can produce actuators with these new components.
Similarly, the standard MLA work at low temperature andhave already been tested in liquid nitrogen (77 K, -196°C):at this cryo-temperature, their strain is only one third of
the one obtained at room temperature. As a consequence,
PPA and APA® offer a reduced stroke; LSPA, LSPS present
a reduced speed.

Maximum Peak-to-Peak displacement & required Pk-to-Pk voltage
400,0

180

1000,0

180

350,0

160

900,0

160

140
120

250,0

100

200,0

80

150,0

60

100,0

40

50,0

20
0,50

1,00
Frequency [kHz]

1,50

0
2,00

© Cedrat Technologies - COMPACT v5.11

Fig. 2.r: APA200M in blocked-free condition, unloaded:
Maximal displacement according to prestress andmaximal applicable voltage versus frequency

140

Mod_a(u) [µm]700,0Pk-Pk displacement [µm]V_a [V]V_a [V]

120

600,0

100

500,0

80

400,0

60

300,0

40

200,0

20

100,0
0,0
0,00

0,05

0,10

0,15
0,20
Frequency [kHz]

0,25

0,30

0
0,35

© Cedrat Technologies - COMPACT v5.11

Fig. 2.s: APA900M in blocked-free condition, unloaded:
Maximal displacement according to pr/stress andmaximal applicable voltage versus frequency

Pk-Pk Voltage [V]Mod_a(u) [µm]

0,0
0,00

800,0
Pk-Pk Voltage [V]300,0
Pk-Pk displacement [µm]Maximum Peak-to-Peak displacement & required Pk-to-Pk voltage

25

Products Catalogue Version 5.1 - Tutorial

2.1.10. DRIVING OF PIEZOELECTRIC ACTUATORS
A piezoelectric actuator is a capacitive device, whose
capacitance is often very large (as much as 110 µF). Sucha device is a difficult load for its driving electronics, sincea significant charge transfer rate is necessary to achievea fast response. In addition the actuator will produce
electrical energy when submitted to a mechanical load.

For a given current limitation Ilim, the shortest charging
time is given by:Linear amplifiers are the most common amplifiers andhave high signal to noise ratio. Switched power amplifiers
are more efficient under reactive loading in dynamic
applications, but have frequency limits due to switching.
The general synoptic of the driving system for a piezoelectric
system is given in Fig. 2.t.

where ΔV is a peak to peak voltage value, ΔV = 2Vp

With a linear amplifier the voltage applied to the actuatoris directly proportional to the input signal. The gain of thepower amplifier is set to 20.

𝑡𝑡𝑐𝑐ℎ𝑎𝑎𝑎𝑎𝑎𝑎𝑎𝑎 =and Vp is the peak value of the sine voltage applied to theactuator.
In dynamic operation, the peak current i flowing into theactuator linearly increases with the frequency of a sine
signal.

𝑖𝑖𝑖𝑖 ≈ 2𝜋𝜋𝜋𝜋𝑓𝑓𝑓𝑓𝐶𝐶𝐶𝐶𝑝𝑝𝑝𝑝𝑝𝑝𝑝𝑝𝑝𝑝𝑝𝑝𝑝𝑝𝑝𝑝𝑝𝑝𝑝𝑝 𝑉𝑉𝑉𝑉𝑝𝑝𝑝𝑝• Input signal: –1 V to +7.5 V• Output signal: -20 to 150 V
Indeed, when the variation speed of the input signal (order)
increases, the current limitation Ilim of the amplifier limits
the slew rate of the output voltage.

The current for a capacitive load is given by the following
expression:

𝐼𝐼𝐼𝐼𝑝𝑝𝑝𝑝𝑝𝑝𝑝𝑝𝑝𝑝𝑝𝑝𝑝𝑝𝑝𝑝𝑝𝑝𝑝𝑝 = 𝐶𝐶𝐶𝐶𝑝𝑝𝑝𝑝𝑝𝑝𝑝𝑝𝑝𝑝𝑝𝑝𝑝𝑝𝑝𝑝𝑝𝑝𝑝𝑝

𝑑𝑑𝑑𝑑𝑣𝑣𝑣𝑣
𝑑𝑑𝑑𝑑𝑑𝑑𝑑𝑑

Due to the peak current limitation, the maximal frequency
for a sine signal is given by:

𝑓𝑓𝑓𝑓sin 𝑚𝑚𝑚𝑚𝑚𝑚𝑚𝑚𝑚𝑚𝑚𝑚 =

Volts

+

Saturation

𝐼𝐼𝐼𝐼𝑙𝑙𝑙𝑙𝑙𝑙𝑙𝑙𝑚𝑚𝑚𝑚∆𝑉𝑉𝑉𝑉 ∙ 𝐶𝐶𝐶𝐶𝑝𝑝𝑝𝑝𝑙𝑙𝑙𝑙𝑝𝑝𝑝𝑝𝑝𝑝𝑝𝑝𝑝𝑝𝑝𝑝 𝜋𝜋𝜋𝜋

The required effective electrical reactive power Q is equalto:𝑄𝑄 ≈ 4𝑓𝑓𝐶𝐶𝑝𝑝𝑝𝑝𝑝𝑝𝑝𝑝𝑝𝑝 𝑉𝑉𝑝𝑝2

where v is the input voltage and Cpiezo is the quasistatic
capacitance of the piezo actuator.

Externalorder∆𝑉𝑉 ∙ 𝐶𝐶𝑝𝑝𝑝𝑝𝑝𝑝𝑝𝑝𝑝𝑝
𝐼𝐼𝑙𝑙𝑙𝑙𝑙𝑙

Low voltage

High voltage
output stage+

High voltage

Volts

Piezo
actuator

Front faceoffsetFig. 2.t: Synoptic of driving systemcompact dynamic precise

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Note: One option available on the linear driver is the push-pull
operation, which can be used to drive tilt devices or electrically
centered mechanisms (Fig. 2.u).

VPP= +130VDC

Piezo Push

Piezo Driver

The resolution of a piezoelectric actuator is limited by theelectrical noise of the driving system. Typical values of thesignal to noise ratio of the driving electronic (below theresonance frequency of the actuator) range from 70 to
85 dB.

Vamplifier = [-20;+150]V

Piezo Pull

MLA always display an hysteresis, which limits the
positioning accuracy. Other effects, such as drift, also
limit the actuator’s linearity. Therefore, displacement
sensors are often used to ensure a linear response of thepiezoelectric actuators through a closed-loop (Fig. 2.w).
When accuracy or speed is required, additional controllers
are implemented in speciﬁc control loop to improve theperformances of the piezoelectric mechanisms. Coupledwith Strain Gauges sensors (SG75 conditioner option) or
Eddy Current Sensor (ECS75 conditioner option), the servo
controller (UC45 or UC55) is ideally the best solution tocontrol the displacement or to reduce the settling time of
the actuators by regulating the applied command.

Fig. 2.u: Push-pull operation using one electric driver

8

x 10

-5

Step
Open-loop
Closed-loop

7
6

See application note “Position control of piezo actuators”
for more information on control : cedrat-tec.com/products/

5

users-manual/electronics.html

4
3
2
1
0

0

0.02 0.04

0.06

0.08

0.1

0.12

Times (s)0.14

0.16 0.18

Fig. 2.v: Comparison between open loop
and closed loop responses

External
order

+

PID
controller

Saturation

High voltage
output stage-

SensorFig. 2.w: Synoptic of a closed loop system

Current limiter

Piezo
actuator

0.2

27

Products Catalogue Version 5.1 - Tutorial

2.2. TUTORIAL ON MAGNETIC ACTUATORS
2.2.1. INTRODUCTION TO MAGNETIC ACTUATORS
Reluctant force actuators (see Table 2.c), are based on
the force resulting from the law of physics, which generates
forces in order to minimise magnetic
energy, in an air gap between two parts
within a magnetic circuit. This law ofphysics results in an attraction force
between the two parts, which is
Fmag
proportional to the square of themagnetic field B² in the air gap. Suchactuators can be realised either withmoving magnets or moving irons (i.e.
fixed coils and magnets such as“MICA™”) or even without magnets (i.e.
“Electro-Magnets”), and have a higher
Fig. 2.x: Laplace force
force capacity compared to Laplace(Moving coil actuator)
actuators (Fig. 2.y).

Magnetic actuators are based on different magnetic designprinciples, which produce magnetic forces, in order togenerate motions, such as displacement
or acceleration, mechanical power, or
static forces.
The magnetic forces production isachieved by the use of a combinationof coils, driven by a current or a voltage
in order to convert electrical power, soft
magnetic materials for the conductingof magnetic fields, and hard magnetic
materials i.e. permanent magnet, togenerate efficient magnetic polarisation.
The magnetic principles allow to takebenefit of two different types of forces
to define actuators topologies, which
are the Laplace Forces, and Reluctant
forces.

𝐹𝐹𝐹𝐹𝑚𝑚𝑚𝑚𝑚𝑚𝑚𝑚𝑚𝑚𝑚𝑚 = 𝐵𝐵𝐵𝐵2𝑆𝑆𝑆𝑆2𝜇𝜇𝜇𝜇0Laplace force actuators, commonly
Fmag
According to the possible combinations’named “voice coil actuators”, aretopologies of these materials, quite
based on the force resulting from thedifferent functions and properties areinteraction of current in coil wire and aobtained.
Fig. 2.y: Reluctant force
magnetic source (resultant of all Lorentz(Moving iron actuator)
forces on electrons) (see Table 2.c).
Magnetic actuators properties are
Such actuators can be realised either
strongly influenced by the mechanicalwith moving coils or moving magnets topologies (i.e. fixed
implementation of moving parts, and the type of motion
coils) (see Fig. 2.x). The Laplace force is proportional to theguiding devices such as compression/traction springs,
magnetic field B in the air gap.
flexure bearings, sliding bearings, ball bearings, or gas
bearing. In most cases, guiding devices present stiffnessthat have to be taken in account in the available output
force analysis. Net force usefull for the application is :𝐹𝐹𝐹𝐹𝑚𝑚𝑚𝑚𝑚𝑚𝑚𝑚𝑚𝑚𝑚𝑚 = 𝐵𝐵𝐵𝐵0 𝐿𝐿𝐿𝐿𝐿𝐿𝐿𝐿

𝐹𝐹 = 𝐹𝐹𝑚𝑚𝑚𝑚𝑚𝑚 − 𝑘𝑘𝑘𝑘
MCA (VOICE COIL )Locking at rest
Magnetic Forcewhen supplied
MotionControllability
Heating
Force / power

MICA™

No in standard
No
Yes, 1 or 2 positions withcustom design
Almost constant along
Rather constant along
the stroke
the stroke
Good
Good
Force can be reversed all Force can be reversed allalong the stroke;
along the stroke
Small Hysteresis
Small Hysteresis
Fast
Slow
Fair
High

ELECTRO-MAGNET

BI-STABLENo
Yes, with spring

Yes, 2 positions

Varying a lot along thestrokeVarying a lot along thestrokePoor
Only attractive force
available

No
Intermediate position
cannot be controlled

Slow
High

Fast
Very highTable 2.c Magnetic actuators

compact dynamic precise

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2.2.2. MOVING COIL ACTUATORS MCA
The Moving Coil Actuators MCA are based on the Laplace
force magnetic principle, which is proportional to theapplied current I and magnetic field B0.

𝐹𝐹𝑚𝑚𝑚𝑚𝑚𝑚 = 𝐵𝐵0 𝐿𝐿𝐿𝐿A MCA is composed of a fix part called stator, and a moving
part. The stator is built with an assembly of magnets andmagnetic circuits (soft materials), that create a static
magnetic field Bo. The moving part is a coil. When supplied
by a current this coil is submitted to a Laplace Force, i.e.
the resultant of all Lorentz
Forces applied on electrons,
and can move in both linear
directions according to thecurrent direction (Fig. 2.aa) .

MCA are well suited for long stroke and high precision
positioning requirements, when compactness, input
electrical power, and operation time, are not the main
drivers for a given application.
Indeed, the flying moving coil in an air gap makes it notpossible to cool it by conduction, and makes it impossible
to cool in vacuum condition, as well as in confinedenvironment with no forced air convection. Continuous
operations are then not possible, operating duty cycle shallbe studied vs temperature.
MCA’s design compactness, and electrical input power,
are difficult to optimise, especially for long strokes, due
to the flying coil having only
partial immersion into themagnetic field, while powered
entirely. This results in poor
compactness, as well as
reduced efficiency and higher
heat dissipation by Joules
effect, compared to otheractuators.

The force being proportional
only to current and magnetic
field, a good linearity of force
versus position of the coil isachieved (Fig. 2.ab), at low
The main advantage of thestroke and force levels,
MCA is the mechanicalleading to a high fidelity insimplicity of the magnetic
response without distortions.
Fig. 2.z: Moving coil linearity of force versus stroke
circuit, that do not need any
Therefore MCA have been
laminations for Eddy current
widely used in loud speakers,
lossesoptimisation,
andthat
generates only little parasitic
called “Voice Coil”, due to this high linearity behaviour inradialforcesonto
themovingpart.
the high frequency domain, were low forces and low
strokes are required.
The moving coil requires special care on to the flying wire
At higher stroke and force level with low to medium
frequencies, this linearity performance decreases due toside effects, imperfect winding patterns, non-homogenous
magnets’ assemblies, and non-parallel line of field in large
air gaps due to the coil thickness.

Fig. 2.aa: Moving coil magnetic principle

electrical lead connections, which are submitted to cyclicalfatigue at high temperature, and which do not make suchactuators compatible with free of maintenance, and longlife nonstop continuous operations over years.

Fig. 2.ab: 100 N Moving Coil Actuator

Fig. 2.ac: 15 N Moving Coil Actuator

29

Products Catalogue Version 5.1 - Tutorial

2.2.3. CONVENTIONAL MOVING IRON ACTUATORS - ELECTROMAGNETS
The electromagnet actuators, which include “Solenoid”
actuators, are based on reluctant forces, with an actuator
topology defined without magnets, i.e. only coils and soft
materials, which require very simple mechanical designs.
The stator is built by assemblyof coils and magnetic circuits,
defining a one pole magneticarchitecture resulting in a single
force direction (attraction).
The moving part, also called“Plunger”, is a soft magnetic
core, typically an Iron alloy, whichallows classifying such actuatorsin the category of Moving Iron
Actuators.

𝑆𝑆𝑆𝑆
2µ0

B is the magnetic field in the air gap and S is the polesurface.

The force is only attractive, whatever the current direction.
This force is highly nonlinear versus the plunger position,
which cannot be controlled without implementing a springback force, using a mechanical flexure bearing, or acompression spring, in order to generate an equilibrium
position at a given current value.

F mag

The main performance of such an actuator, comparedto other magnetic ones, is the force response time
performance achieved over very compact and light moving
part, which makes it best applicable for demanding fast
operational requirements.
This performance can be increased to best possible using
current shaping drive electronics, which allow suppressing
the field setting time due to Eddy currents in the magnetic
circuit, as well as the mechanical response time of themoving plunger mass, by generating a transient force
profile with a high peak value.
A current shaping electronic method can be used toincrease speed, and reduced response time to reacha plunger position in proportional control, or a closing
position, as well as to reduce shock impacts on end stops
at closing, or for any combination of both.

Voltage(V)+24V

Drive electronic inlet
command signal
Drive electronic output
voltage

End stop

Magnetic
force (I)In order to generate a position
proportional to the current, at
first the moving part is attached
to a spring generating a backforce. Secondly, the reluctant
force non linearity versus position
can be partially suppressed ina given stroke range using FEM
optimisation of poles shape.

Fig. 2.ad: Electromagnet for proportional
force to current actuation

When the coil is supplied by a current I, an attractive
magnetic force Fmag is developed in the air gap between theplunger and the electromagnets actuator poles. For
actuators with stroke perpendicular to the air gap Fmag is
given by :𝐹𝐹𝐹𝐹𝑚𝑚𝑚𝑚𝑚𝑚𝑚𝑚𝑚𝑚𝑚𝑚 = 𝐵𝐵𝐵𝐵2

The force and stroke available from such actuators arevery high compared to their very small size, which makeit especially attractive for miniature and fast position
switching and control applications, such as on/off andfast regulation valves in fluid
applications.

+5V
Opening command
+3,3V
0V

Spring force

StableStableposition (x)Fig. 2.ae: Proportional linearisation sizing

0V

Closing command
15ms

8ms

-24V

Fig. 2.af: Current shaping profile

Time (ms)compact dynamic precise

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2.2.4. MOVING IRON CONTROLLABLEACTUATORS MICA™
Moving Iron Controllable Actuators MICA™ are based on
reluctant forces, as per electromagnets, but with amagnetic topology polarised with permanent magnets, inorder to achieve a variable reluctance according to thecurrent direction (Fig. 2.aj). This topology allows a force
and motion direction change, according to the current
direction, as per Laplace force actuators.

𝐹𝐹𝐹𝐹𝑚𝑚𝑚𝑚𝑚𝑚𝑚𝑚𝑚𝑚𝑚𝑚 = 𝐵𝐵𝐵𝐵𝑑𝑑𝑑𝑑

𝐵𝐵𝐵𝐵𝑠𝑠𝑠𝑠 𝑆𝑆𝑆𝑆𝜇𝜇𝜇𝜇0

where Bd is the dynamic magnetic field in the
air gap due to the coil current, Bs is the static
magnetic field due to the permanent magnets
and S is the pole surface.

This formula (strictly valid when the actuatoris centred) shows the force is proportional tothe coil current. As shown on Fig. 2.ah and Fig.
2.ai, a good proportionality is even achieved inlarge ranges of positions and currents aroundthe centre and the zero current.

with either “Moving Rod” or “Moving Cylinder” application
requirements.
Core improvement achieved by the MICA™ technology
is the suppression of any limited life wire electrical flying
connection, which helps achieving infinite fatigue life.
This is especially the case when used in combination
with frictionless flexure bearings (Fig. 2.ak and Fig.
2.ag), instead of classical sliding friction bearings, or ballbearings. This featuring allows achieving on going nonstop
operation over years without maintenance.

The enhanced force and compactness performance, givenby the MICA™, is to the cost of decreased linearity of force
versus position compared to moving coil ones, for longstroke applications, but neverthelessacceptable in most cases. This linearity
decrease being also a featuring of highforce/stroke moving coil actuators, otheradvantages of moving iron ones are
considered as predominant especiallyconsidering the use of current shaping
drive electronics, allowing linearisationand suppression of harmonic distortions,Fig. 2.ag: MICA300CM
and reduced response time increasing
moving mass acceleration capabilities.

This “Variable Reluctance” magnetic principle allows the
MICA™ to be classified in the category of “Permanent
magnet based actuators”.
The MICA™ achieves a performance breakthrough,compared the weaknesses of the former state of theart on moving coil one, especially in terms of efficiency,
compactness, and long life nonstop continuous operations
over years without maintenance.
This enhanced feature is achieved by the use of a magnetic
principle having both coils and magnets fixed (Fig. 2.ak),
allowing an efficient heat dissipation by conduction.
Moving Iron parts have compact dimensions and low masscompared to moving coils. Finally moving parts need noelectrical connection nor heat dissipation.
Compared to former voice coil technology, this actuator
topology offers a higher force per mass and per input
power. This allows a long term operation at stabilised low
coil temperature, as well as optimum electrical input powerwith reduced coil Joules effect. Best electrical efficiency
performance is achieved by optimization of eddy current
losses in both fixed and moving Iron assemblies.
The MICA™ mechanical simplicity allows design
configuration over wide range of possibilities, usingsquare or cylindrical housing structures, as well as director reversed coaxial arrangements to fit custom solutions

2.2.5. BISTABLE LINEAR MOVINGMAGNETS ACTUATORS BLMM
Bi-stable Linear Moving Magnets actuators BLMM arebased upon the reluctant force principle, achieved with a
combination of permanent magnets, and electromagnets.
Such an actuator topology allows achieving two stable
positions at rest, maintained by the magnetic holding force
provided by magnets, and without requiring any electrical
power nor dissipating any heat. Commutation between
the two positions is achieved by applying short electricalimpulses, at fast speed, and short response time (Fig.
2.al).
The BLMM are composed of two fixed parts, realised withtwo back to back electro-magnets (Fig. 2.am), eachcombining coils and soft materials, and a moving partcomposed of a magnet assembly and a shaft structure.
Bi-stable actuators are perfectly suited for commutation
mechanism, such as contactors, locking devices, and latch
mechanisms (Fig. 2.an). Most common application of bistable actuators is for on/off latch electro-valves in fluid
applications. The advantage of bi-stable actuators,
realised with BLMM permanent magnets magnetic
topology, is the high level of miniaturisation achievable(Fig. 2.ao), while keeping a fast commutation speed, anda high holding force at rest.

31

Products Catalogue Version 5.1 - Tutorial

Fig. 2.ah: MICA™ linearity profile of force vs position

Bs
Bd

Bd
Bs

Fig. 2.aj: MICA magnetic principle

Fig. 2.ai: MICA™ linearity profile of force vs current

F
Fig. 2.ak: MICA20CS

Fig. 2.al: Force vs Position

Fig. 2.am: BLMM magnetic principle

Fig. 2.an: Customised BLMM200M actuator
offering 200 N locking force

Fig. 2.ao: CTEC miniature BLMM1XS actuators

compact dynamic precise

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2.2.6. LIMITED ANGLE TORQUE ACTUATORS LAT
Limited Angle Torque LAT are high resolution cog-freerotational actuators. They are the counter part ofcontrollable linear magnetic actuators, achieved withsame magnetic principles but in rotational configuration
instead. Such actuators can be realised with both reluctant
and Laplace force principles.

electrical commutation electronic required, and with two
ways motional directions according to current direction.
This feature allows achieving both closed loop feedback
control, as well as open loop proportional control using
angular spring back flexural pivots.

LAT technologies feature perfect angular motions, without
any magnetic incremental stepping, limiting angularresolution, and generating vibrations. LAT actuators’
topologies are achieved instead with single phasecoil assemblies, allowing true DC control, without any

Most recent actuator topology, achieving highest
performances, is the MICA™ LAT technology, which is thecounterpart of Moving Iron Controllable Actuator linear
topology, in rotational configuration. This design option
feature same advantages, with fixed coils and fixedmagnets, allowing efficient thermal heat sinking byconduction, and without limited life wire electrical flying
connection. As per the linear versions of MICA™ actuator,
theoretical infinite fatigue life is achieved, especiallywhen used in combination with friction less bearings,
instead of sliding friction or ball bearings. This featuring
allows achieving on going nonstop operation at stabilized
low coil temperatures, over years and without maintenance,even under vacuum or confined environments without air
convection. Advantages of current shape electronic
methods are also applicable to MICA™ LAT actuators, inorder to linearise torque versus position, increase rotor
acceleration capability, and to reduce response time.

Fig. 2.ap: Moving magnet LAT

Fig. 2.aq: Moving coil LAT

LAT actuators are composed of fixed parts called “Stators”,
and moving parts in rotation called “Rotors”. They can berealised using either moving iron, moving magnet, or
moving coil actuator topologies.
LAT actuators are single phase actuators, which are analternative solution, compared to multiphase electricmotors. The LAT actuator technologies take benefitof dedicated limited angle actuator designs, whichmakes them more relevant for angular position control
applications, with enhanced performances compared to
BLDC motors.

33

Products Catalogue Version 5.1 - Tutorial

2.2.7. CHOOSING VOLTAGE OR CURRENT ELECTRICAL DRIVING PRINCIPLES
The drive electronic principle for a given actuatorapplication, has to be chosen not only according toelectrical requirements of the actuator
itself, but also according to the control
logic. The existing drive electronic
options are divided in two categories, i.e.
voltage control electronics, or current
control electronics.

cyclical input commands shapes, but differs if not thecase, due to the 90 degrees response lag between the two.
When used with the objective of
increasing transient performances,such as enhanced moving massacceleration, and reduced responsetime in actuator position control, current
based drive electronics have far better
performances. Indeed, this second
Voltage control electronics provide
category has the so called “Current
optimised control to apply a given
Shaping” capability, which differs fromvoltage at the actuator wire lead
output current control achieved by a PID
connection. The current delivered to thetype controller (Proportional Integral
actuator coil is then the result of the
Derivative) driving a voltage based
actuator electrical impedance.
electronic. Linearisation of force versus
current, as well as fast response time
Current control electronics provide
are achieved with far better performance
optimised control to apply a given
with an electronic that control current,
current to the actuator wire lead
Fig. 2.ar: CTEC CSA96 : current
instead of voltage. Indeed the current
connection. These are the most adapted
based drive electronic
based drive electronics have thedrivers for magnetic controlable
capability to withstand output peakactuators as their force is proportional tovoltageshapesnotaccessible by PID voltage control,
the current. The voltage applied to the actuator coil is thenwhich
resultsinenhancedactuator response time in
the results of the actuator electrical impedance.
position control.
Both electronics categories have similar performances
when used with linear actuators, and with sine wave
70

60

2.5

60

50

2

30

Position
Force

1

20

0.5
0

0

100

200
Time (ms)

300

40

1.5

10

0.5

0

0

0

Fig. 2.as: Closed loop Voltage driver - Position

Voltage (V)0.8
0.6
Voltage
Current

0.4
0.2
0
0

100

200
Time (ms)

300

400

Fig. 2.au: Closed loop Voltage driver - Voltage

200Time (ms)

300

400

5
4.5
4
3.5
3
2.5
2
1.5
1
0.5
0

40
35

30
Voltage (V)

5
4.5
4
3.5
3
2.5
2
1.5
1
0.5
0

1

100

Fig. 2.at: Closed loop Current driver - Position

Current (A)

1.2

20
10

0

400

30

Position
Force

1

Force (N)

40

1.5

50

25
Voltage
Current

20
15
10

5
0
0

100

200
300
Time (ms)400

Fig. 2.av: Closed loop Current driver - Voltage

Current (A)23

Position (mm)Position (mm)

2.5

70

Force (N)3compact dynamic precise

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2.2.8. ELECTRICAL IMPEDANCEADJUSTMENT

2.2.9. RESONANT FLEXURE BEARINGACTUATORSElectrical impedance matching of an actuator coilassembly, either standard or custom, allows adjusting theoutput performance of this actuator when used with agiven drive electronic, or power source.

Resonant flexure bearing actuators are actuators having
a specific mechanical design based on frictionlessbearing components called “Flexures”, which consist
in planar springs of thin thickness having infinite fatigue
lifetime capability. Flexure bearing actuators can berealised with any magnetic topology, such as moving coil,moving magnets, moving iron, and MICA™. The flexures
are anchored in the stator mechanical parts, and insure
the moving mass motion guiding
in both axial and radial directions,with no sliding friction, no lubricant,and no material wearing.

Drive electronics, and power source hardware, having
limited output voltage and current capabilities, the force
output of an actuator is not limited first by either its
magnetic or mechanical designs, but instead by the input
supply limitations in voltage andcurrent. The tuning of the actuator
electrical impedance defines
its performance output to given
current and voltage input supply,that defines its boundaries limits
in force, acceleration, and heatdissipation, versus frequency. For
that reason the drive electronic
limits reduce the available output
performances of a given actuator
as follows:

When a “fixed coil” actuator
magnetic topology is chosen,s u c h a s m ov i n g m a g n e t ,moving iron, no coil wire flying
lead connection is submitted tocyclical fatigue. Therefore whenused in combination with flexure
bearings, the complete actuator
Fig. 2.ax: Flexure bearings
assembly achieves infinite fatigue• Current limit: limitation of force
lifetime capability. Flexure bearing
and acceleration
actuators are therefore best candidates for applications
requiring long lifetime without maintenance.
• Voltage limit: limitation of the frequency bandwith
Adjusting the electrical impedance of an actuator consists
either in:• Increasing the coil wire diameter to increase thefrequency bandwith, but to the cost of a decrease inforce and acceleration capabilities. (i.e. reduction of
number of wire turns in same coil volume)• Reducing the coil wire diameter to increase the force
and low frequency acceleration capabilities, but to thecost of a frequency bandwith decrease. (i.e. increase of
number of wire turns in same coil volume)

The use of flexure bearing actuators allows taking benefitof the mechanical resonance given by the association of
the moving assembly mass and the stiffness of theflexures. This resonance can be used either to achieveinertial force higher than the magnetic force alone, forapplication such as vibration cancellation using proof
mass actuators, or to achieve high efficiency for power
application such as pumps and compressors.

Electrical Impedance Adjustment

100

Acceleration (g)The flexure bearing actuators have enhanced position
control performances, and allows achieving ideal “stepand stay” control precision and response time, thanks
to the frictionless moving mass motion which is free ofany stick slip parasitic effects as met in friction bearing
actuators (Fig. 2.az).

10
1mm wire
2mm wire
3mm wire

1

0.1

10

100
1000
Frequency (Hz)Fig. 2.aw: Impedance adjustment with wire section selection

Fig. 2.ay: Stick-slip effect in step and stay position
control of friction bearing actuator

35

Products Catalogue Version 5.1 - Tutorial

Output force

F

F

M

Uo

Actuator moving mass

U
Actuator flexure bearing

R

700

90
80
70
60
50
40
30
20
10
0

Mechanical PowerElectrical power
Iron Losses
Joules Losses
Efficiency

600
Power (W)

Magnetic Force
Inertial ForceHeat dissipation

180
160
140
120
100
80
60
40
20
0

Heat dissipation power (W)Force (N)Fig. 2.ba: Power application (compressor)

500
400
300
200
100
0

2

100
1000
Frequency (Hz)

20

200

Frequency (Hz)Fig. 2.bb: Inertial force application - Force analysis

Fig. 2.bc: Power application - Efficiency analysis

Fig. 2.bd: Non linear flexure
bearings - Ortho-radial shape

Fig. 2.be: Linear flexure bearings- Spiral and circular shapes

Non Linear Flexure Bearing - End Stop EffectNon Linear Flexure Bearing - End Stop Effect
4
3.5
3
2.5
2
1.5
1
0.5
0

100
Linear Flexure Bearing
Non Linear Flexure Bearing

80

Linear Flexure Bearing
Non linear Flexure Bearing
10

60

110

160

Spring Back Force (N)Stroke (mm pk-pk)

Actuator flexure bearing

Efficiency analysis

Force Analysis

10

Actuator moving mass

R

Inertial output force

Fig. 2.az: Inertial force application (proof mass)

900
800
700
600
500
400
300
200
100
0

M

Efficiency (%)UoU(Gaz) Spring and resistive load

60
40
20
0

0

0.5

1

1.5

2

Frequency (Hz)Moving Mass Stroke (mm)Fig. 2.bf: Stroke vs Frequency

Fig. 2.bg: Spring back force vs Moving mass stroke

2.5

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compact dynamic precise

When choosing the MICA™ magnetic topology, additional
enhanced cleanliness properties are possible, thanks toboth fixed coil and fixed magnets, which can be assembled
over side from a leak tightened stator assembly. Therefore
in high purity gases, and liquids applications, in domains
such as medical, food, or cryogenics, which havebiocompatibility or high cleanliness level requirements,
the MICA™ actuator topology warranties that only themovingassembly
materials are in contact
with the media. Thisfeature allows achieving
ultralow outgassing
performances, thanks to
the very simple moving
iron mechanical design,
having only metallic
mechanical assemblies,
free of bonding as well as
plastic components andcorrosion sensitive parts,
which can generatecontaminants over time in
the media.

When considering the resonant effect two categories offlexures can be proposed, according to the requirementsof the application:• When the resonance is intended as performancesenhancement, for vibration cancellation proof mass
applications or for power efficiency applications such ascompressors and pumps, high linearity is required, andlinear spiral & circular flexure types are best suitedand proposed by CTEC.
• When the resonance ispotentially a parasitic effect,
for applications such asenhanced frictionless stepand stay position control,
nonlinear orthoradial “endstop effect” flexure types
are proposed by CTEC,
which provide nonlinear
stiffness that suppresses
the magnitude factor atresonance, by frequency detuning.

In order to achieve reliableflexure bearing actuators
manufacturing, with
Flexure bearings of various
appropriate long lifetime
designs are proposed by
fatigue per formances,C e d r a t Te c h n o l o g i e s
special care has to be given(CTEC), according to stroke
Fig. 2.bh: Flexure bearings
to the manufacturing of theamplitudes and linearity
bearings, which are affected
requirements, as well as
by the scattering of theactuator housing shapes that could be either cylindrical,
machining processes. For that reason, process qualification
rectangular, or of any other one. Achieving infinite fatigue
is required, and controlled batch manufacturing approach
lifetime designs, with proper manufacturing processes, isis required for large quantities, which is a key knowhow ofa core knowhow that has to be developed andCTEC.
demonstrated over years with experimental statisticalresults on product series, as well as lifetime cyclical fatigue
tests.

Fig. 2.bi: MICA300CM

Fig. 2.bj: MICA200M

Fig. 2.bk: MICA20CS

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2.2.10. ELECTROMECHANICAL LIMITS OF ACTUATORSElectromechanical limits of actuators have to be
calculated to estimate the performance for given
application requirements, and according to the selected
drive electronics. In order to achieve such calculation
CTEC has developed in house COMMACT™ software(Computation of Magnetic Actuators) that performs
complex actuator analysis, based on the connected
application stiffness, work load, and mass, and taking into
account actuators’ magnetic designs, losses, electrical
impedances, as well as the drive electronics output current
and voltage limits.
A magnetic actuator, in dynamic operation, can bemodelled by a generic Laplace law, which makes use of theforce constant (magnetic force to current ratio) FK, as
follows:

With:• FK I(t) = Magnetic force produced onto the movingmass• F(t) = External force applied onto the moving mass
• m = Moving mass• θ = Iron loss equivalent damping• k = Stiffness of the flexure bearings

In the frequency domain the coupled equations results inthe following electrical scheme, which is composed of anelectrical impedance, and a motional one which traduces
the back electromotive force of the actuator:

𝑈𝑈(𝜔𝜔) = [𝑍𝑍𝐸𝐸𝐸𝐸𝐸𝐸𝐸𝐸𝐸𝐸𝐸𝐸𝐸𝐸𝐸𝐸𝐸𝐸𝐸𝐸 + 𝑍𝑍𝑀𝑀𝑀𝑀𝑀𝑀𝑀𝑀𝑀𝑀𝑀𝑀𝑀𝑀𝑀𝑀 ]𝐼𝐼(𝜔𝜔)𝑈𝑈(𝑡𝑡) − 𝐹𝐹𝐹𝐹 𝑥𝑥̇ (𝑡𝑡) = 𝑅𝑅0 𝐼𝐼(𝑡𝑡) + 𝑅𝑅0 𝐼𝐼 (̇ 𝑡𝑡)
With:• U(t) = Voltage

Electrical• I(t) =Current• Ro = Coil resistance• Lo = Coil inductance• FK = Magnetic force to current ratio• Ẋ = moving mass speed

By combining this equation with the dynamic mechanicalone, of the moving mass mechanism, by taking inconsideration the flexure bearing stiffness, and Iron loss
coefficient, one can derive the coupled electro-mechanicalequation in order to calculate the different electrical andmechanical parameters behavior.

𝐹𝐹𝐹𝐹 𝐼𝐼 (̇ 𝑡𝑡) − 𝐹𝐹(𝑡𝑡) = 𝑚𝑚 𝑥𝑥̈ (𝑡𝑡) + 𝜃𝜃 𝑥𝑥̇ (𝑡𝑡) + 𝑘𝑘 𝑥𝑥(𝑡𝑡)Ro

Motional

Lo

Zm

I(t)

U(t)

Fig. 2.bl: Equivalent electrical scheme of magnetic actuator

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Limits analysis
Strokelimitation Area

120

Current
limitation Area

Voltagelimitation Area

Percent of limit (%)

100• Actuator stroke limit (low frequency range)

8060% Voltage Limit% Current Limit% Stroke Limit

40
20

0
10

100
Frequency (Hz)1000

Fig. 2.bm: Limits analysis

Aceleration (g)

100

10

Unloaded
1kg load
2kg load1
10100
Frequency (Hz)• Drive electronic output current limit (medium frequency range)• Drive electronic output voltage limit (high frequency range)
Given the frequency domains limits can be calculated the actuator
different performances such as maximum acceleration and inertial
forces versus frequency.

2.2.11. ACTIVE & REACTIVE ELECTRICAL POWER

Acceleration limits analysis

1000

Fig. 2.bn: Acceleration limits analysis

Inertial Force Analysis

1000

Force (N)Such modelling approach allows to calculate for given combinations ofactuator, drive electronic, and application load, the frequency domain
limits which mainly consist in:Power applications require the use of an actuator operated in order togenerate or absorb mechanical power. For that, the actuator moving
mass is put in motion by the magnetic force, in front of a mechanicalresistance that absorb or dissipate mechanical power. Such an actuator
operation is typically required for linear thermal machines such ascompressors, pumps, pressure wave generators, and for linear energy
recovery machines such as linear alternators, and gas expanders.
Such an operation of an actuator is characterized by the requirement of
producing a force against a mechanical device that will absorb, or
dissipate, the mechanical power by means of a phase lag between theactuator moving mass velocity, and output force, lower than 90°.
Therefore, in that specific case, the electrical power absorbed by theactuator is used to compensate the output mechanical power and theactuator losses, i.e. Joules and iron losses, which are dissipated into
heat. The efficiency of the actuator and associated heat dissipation,
during this operation are then defined as follows:100
Unloaded
1kg load
2kg load

10
1
10

100

1000

Frequency (Hz)Fig. 2.bo: Inertial force analysis

In most application the output mechanical power provided by an actuator,
connected to a given application, can be analysed with a viscous damper
work load analogy.
Considering the phase lag between the damper force 𝐹𝐹⃗ and⃗ φ=0° to achieve the maximum power, the output mechanicalvelocity 𝑉𝑉
power integration of the actuator over a period is positive.
𝑇𝑇

F

U

Uo
R

M

Actuator moving mass
Actuator flexure bearing
Inertial output force

Fig. 2.bp: Inertial force application (proof mass)1
1⃗⃗ ‖ cos 𝜑𝜑 = 𝑅𝑅𝐿𝐿 𝑉𝑉 2
∫ 𝐹𝐹⃗ ⃗⃗⃗⃗
𝑉𝑉 = ‖𝐹𝐹⃗ ‖‖𝑉𝑉
2
2
0

with RL = resistive load

The limit analysis performed with COMMACT™ software allows providing
the actuator force limits, electrical power, efficiency, and heat dissipation.

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Products Catalogue Version 5.1 - Tutorial

The analysis of power factor allows to estimate the global efficiency the
combination of Actuators plus Drive Electronics, by calculation of the socalled “Active Power” and “Reactive Power”.

100

1
10

1

100
Frequency (Hz)Fig. 2.bq: Power and efficiency analysis

600

Force (N)

500

500

400

400

300

300

200

Magnetic ForceApplication force
Electrical power

100
0

10

If a drive electronic without reactive power recovery capability is chosen
for high power application, the combination of electronic plus actuator
should be used as close as possible to the resonance frequency, where
the actuator power factor is the highest close to cos(φ)=1, otherwise
very significant heat dissipation shall have to be handled by the drive
electronic using fans or refrigerant cooling loops. The drive electronic
efficiency is therefore highly affected by the actuator power factor:

700

200
100

Electrical power (W)Force Limits and Electrical Power

600

𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐴 𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑅 𝐼𝐼𝐼𝐼𝐼𝐼𝐼𝐼𝐼𝐼 𝑃𝑃𝑃𝑃𝑃𝑃𝑃𝑃𝑃𝑃 = 𝑉𝑉𝑟𝑟𝑟𝑟𝑟𝑟 ∙ 𝐼𝐼𝑟𝑟𝑟𝑟𝑟𝑟 ∙ sin 𝜑𝜑∙0100Frequency (Hz)Fig. 2.br: Force limits and electrical power

Electrical power analysis

1100Electrical power
Power Factor

Power Factor

Electrical Power (W)

1000

10

With the objective of providing high efficiency combinations of actuatorand drive electronic, CTEC has developed drive electronics (such as
CSA96) with reactive power recovery feature which allows achieving
electronics efficiencies higher than 90%.

10Electrical power
Mechanical PowerHeat dissipation
Efficiency

10

𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐴 𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐴 𝐼𝐼𝐼𝐼𝐼𝐼𝐼𝐼𝐼𝐼 𝑃𝑃𝑃𝑃𝑃𝑃𝑃𝑃𝑃𝑃 = 𝑉𝑉𝑟𝑟𝑟𝑟𝑟𝑟 ∙ 𝐼𝐼𝑟𝑟𝑟𝑟𝑟𝑟 ∙ cos 𝜑𝜑• The reactive power is the electrical power stored by the actuator,
toward the drive electronic, which shall be converted into heat by thedrive electronic itself if not featured with energy recovery capability.
The reactive power is defined by the counterpart of power factor
sin(φ) with φ being the phase lag between the actuator input voltage
and current.

100
Efficiency (%)

Power (W)• The active power is the electrical power absorbed by the actuator,
which shall be converted into output mechanical power for theapplication, and heat dissipation accordingly to the actuator efficiency.
The active power is defined by the power factor cos(φ) with φ being
the phase lag between the actuator input voltage and current.

Power and Efficiency Analysis
1000

0.1
10

100
Frequency (Hz)Fig. 2.bs: Electrical power analysis

Fig. 2.bt: CSA96-IS

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2.2.12. MAGNETIC ACTUATORS HEAT DISSIPATIONHeat dissipation analysis

Heat dissipation (W)1000

Heat dissipation analysis is a key result that need to be taken into
account for the operability of a given actuator over time. This result canbe obtained for whatever application case, and actuator technology by
the use of the in house Cedrat Technologies (CTEC) COMMACT™
software.

100
Unloaded
1kg load
2kg load

10

1
10

100

1000

Frequency (Hz)Fig. 2.bu: Commact™ - Vibration assistance application

Heat dissipation
Efficiency
10

100
90
80
70
60
50
40
30
20
10
0

Efficiency (%)

Power (W)

Efficiency Analysis - Heat Dissipation
128
126
124
122
120
118
116
114
112
110

100

Frequency (Hz)Fig. 2.bv: Commact™ - High efficiency power application

Comparison MCA and MICA™ @ Stall Force700

MICA™ (Moving Iron Actuator)
MCA (Moving Coil Actuator)

Inertial force (N)

600
500
400
300
200

100
0
10

100

1000

10000

Frequency (Hz)Fig. 2.bw: Comparison of same size MCA
and MICA™ at nominal force

Heating Time with Natural Convection
Coil Temperature (°C)

250

MICA™(Moving Iron Actuator)
MCA (Moving Coil Actuator)

200
150

360 s

750 s

100
50
0
0

200

400

600

800

Time (s)Fig. 2.bx: Comparison of same size MCA andMICA™: Heating time with natural convection

This information gives a quantitative value of a heat dissipation power,
but then has to be analyzed in terms of heat sinking capability, toestimate the temperature increase and stability over time of a given
actuator. Two categories of actuators’ technologies have to be considered:Moving Coil Actuators, which have flying coil, have no coil heat sinking
capability, and the coil can only be cooled by Air convection within the
sharp and confined magnetic field gap of the actuator, where the coil ismoving. Therefore for such an actuator, the maximum coil temperature(~150°C to 200°C) is achieved very quickly, and the actuator output
force has to be reduced in order to operate at a coil temperature notexceeding this value. For a given environmental Air convection condition,
natural, or forced, this maximum force value is sometime called “Nominal
Force”, “Continuous force” or “Stall Force”. As the Air convection
cooling capacity is highly linked to the application confinement, thisnominal force value differs for each case, is not easily predictable, andis the major limitation of the moving coil technology, reducing verysignificantly the allowable force for continuous operation, compared the
maximum force called “Peak Force”, only available during very shortterm operation. As the operational temperature of moving coils is high,the efficiency losses by increase of Joules effect is a significant
consequence, due to wire resistivity increase at high temperature.
Fixed Coil Actuators, which includes Moving Magnets, Moving Iron,
and MICA™ actuators have far much better heat sinking capabilities
compared to moving coil ones. A fixed coil winded over a mechanicalstructure have heat sinking capability by conduction, which is notpossible with a flying coil. This heat sinking by conduction allows
achieving remote coil cooling by either passive natural air convection,using external fins on the actuator structure, or active cooling using
external refrigerant cooling loops or forced air convection. Whenconsidering passive natural convection, fixed coil actuators can havesignificantly greater “continuous force” capability compared to moving
coil actuators, and much longer heating time toward classical allowed
150°C coil temperature, as well as much faster temperature decreaseat rest. When considering actively cooled long term continuous operation,
fixed coil actuators can operate at stabilised low coil temperature,
which is much more favorable from Joules effect point of view andefficiency, whereas such equivalent low temperature continuous
operation is not possible with moving coil actuator for the samemechanical load.

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2.2.13. ANALYSIS OF MAGNETICACTUATORS WITH LOSSES

Actuator Losses and Non Linear load cumulated effects
Actuator with mechanical losses
Ideal Actuator
Actuator with Iron Losses
Actuator with non linear load

Analysis of magnetic actuators with Losses is a key analysis which canbe performed using the CTEC in house COMMACT™ software. This
analysis allows estimating true actuator performances, taking in accountthe different sources of loss that will be converted into heat, and which
will reduce the actuator targeted performances:

Stroke (mm pk-pk)

4
3
2

1
0
10

• Joules losses

60

110Frequency (Hz)160

Fig. 2.by: Stroke vs frequency• Mechanical viscous and solid frictions losses• Actuator Iron losses• Application nonlinear effects (as friction)

Application non linear effects, such as friction, non linear stiffness andnon linear work load, are non direct losses because they do not result
directly in a conversion of input power into heat dissipation. Such effects
induce indirect losses because they induce a decrease of mechanicalpower factor, and electrical one, as well as a magnification factor
decrease by frequency de-tuning. The actuator acts again a “virtual end
stop stiffness” that requires higher force to achieve the targeted
displacement. The decrease of electrical power factor induces anadditional electrical loss due to a significant actuator reactive power,that is converted into heat by Joules effect if the drive electronic does notfeature energy recovery capability.
Cumulating all losses can result in a significant decrease of performancecompared to expected, if not taken in account. In custom designs for
power efficiency application such as thermal machines, pumps, andcompressors, all losses are to be reduced as much as possible by design,using frictionless flexure bearings, as well as soft material assemblies
composed of optimised finned, slotted, sintered, or laminatedmechanical parts.

Actuator Efficiency (%)

Iron losses are magnetic losses that include Eddy currents andHysteresis losses, which reduce both the moving mass magnification
factor, and the actuator frequency bandwith.

Actuator Losses and Non Linear load cumulated effects
Actuator with mechanical losses
Actuator with non linear load

Ideal Actuator
Actuator with Iron Losses

80
60
40
20

0
10

60

110
Frequency (Hz)160

Fig. 2.bz: Efficiency vs frequency

Actuator Losses and Non Linear load cumuated effects
Ideal Actuator
Actuator with mechanical losses
Actuator with Iron Losses
Actuator with non linear load

Electrical Power Factor (--)

Mechanical losses reduce the magnification factor of a given actuators
moving mass, which means that a higher forces are required to achieve
the targeted stroke and acceleration.

0.6

0.4
0.2
0
10

60

110

160

Frequency (Hz)Fig. 2.ca: Electrical power factor vs frequency

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For more information on this chapter,
please visit these pages:
cedrat-tec.com/applications
cedrat-tec.com/technologies

Products Catalogue Version 5.1 - Markets & Applications

3. MARKETS & APPLICATIONS
3.1. MARKET OVERVIEW
Products and developments provided by CEDRAT TECHNOLOGIES (CTEC) find applications in all
the fields of mechatronics. The major ones are air & space, optronics, scientific instrumentation,
production and manufacturing and medical technology.
All these application fields gather round advanced functions requiring fast or precise actuation:
precise positioning, fast displacement, vibration/force generator, vibration damping. Somerelated applications and their working conditions are given in section 3.2, page 45.
CTEC, as a customer-oriented company, manufactures and sells not only standard products, butalso customised solutions, especially for OEM (Original Equipment Manufacturer) series.
The range of standard actuators from CTEC is a first commercialy off the shelves (COTS) solution
for satisfying a wide spectrum of technical specifications & environmental conditions in shorttime delivery. Some of the products presented in this catalogue are in “preliminary data” asnoted in their performance table. It means those products are not available off the shelves
and may require some extra engineering work to be so. To satisfy some demanding customer
requirements met in OEM business, CTEC can optimise, adjust and extend the performances of
its actuator technologies. The aim is to be compliant with technical, environmental, economicalor other specifications that are necessary to provide the customer with the best value added on
its system integration. Several situations may arise:• Some performances like stroke or force of standard actuators have to be increased,• The mechanical interfaces have to be adjusted to make the final integration easier,• The application requests a more complex mechanism than a single actuator,• A special feature such as non-magnetism or harsh environment compatibility is required.
Solutions to remove these limitations are shown through applications in section 3.2, page 45
and are completed with additional technological solutions introduced in section 3.3, page 54.
In all these cases, CTEC can provide all the services presented in section 1.4, page 12 tohelp the customer with a fast solution combining its existing products, its building blocks, its
experience and its development facilities.

The technical information on this chapter is not contractualand can be changed without prior notice.

43

CEDRATTECHNOLOGIES
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compact dynamic precise

INSTRUMENTATION• Telescope mirror motorisation• Syncrotron fasts shutters• Environmental & material testing• Beam shaping

OPTRONICS• Micro-scanning & pixel shifting• Optical image stabilisation• Autofocus• Embedded mechatronic functions

AIR & SPACE• Optical mechanisms flight hardware• Scan mechanisms for earth observation• Hold-down release mechaisms ( HDRM)• Fast steering mirrors

MEDTEC• Micro actuation• Miniaturised motorisation• Microfluidic control device

MANUFACTURING• Chatter cancellation• Vibration assistace for machining• Active clamping fixtures

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Products Catalogue Version 5.1 - Markets & Applications

3.2. APPLICATIONS & FUNCTIONS CLASSIFIED BY WORKING CONDITIONS
The working conditions are the kinematic conditions sothat the inertia and dynamic force impacts on the actuator
are taken into account. The working conditions are split
into several kinematic conditions: static, dynamic nonresonant, resonant...
The function is the type of physical action or operation(force, motion, vibration,…) that the actuator generates
on the user’s system. The function is the answer to thefollowing question: How is the actuator used inside thesystem?

The application is the result of the actuator’s function
inside the system. The application is the answer to thequestion: What is the actuator’s operation/function usedfor?
The working conditions can be more or less demanding forthe actuator and the electronics. They are associated todifferent frequency regions, introduced in previous section.
Most of CEDRAT TECHNOLOGIES (CTEC) actuators canoperate under dynamic conditions, which opens them to awide range of applications and markets. To select anactuator for a given application, it is useful to know its
function and working conditions (see Table 3.a).

WORKING
CONDITIONSIINERTIALFORCESELECTRIC
POWER

StaticNegligible

Negligible• Micropositioner• Slow actuator• Force Generator• Micro & Nano positioning• Flow control• Material Stress testingNot negligible

Can be very high andmay be the limiting
factor• Wide bandwidth• Vibration generator• Vibration damper• Fast actuator• High frequency Shaker• Forced Vibration Assistance• Active damping, Isolation• Shutter, XY Scanning• Fast positioning• Material stress cycling

Dynamic
Strain atresonanceHigh

Not negligible(Applied voltage
should be monitored)• High-amplitude• Vibration generator• Sonic transducer• Ultrasonic transducers• Resonance Vibration• Assistance to process• Ultrasonic welding, microinjection moulding …
• Fluid degassing, cleaning

Dynamic
force

High

High

• Proof-mass vibration / force
generator• Proof-mass vibration damper• SHM structure exciters• Hammer• Active damping of structures

Impulse
Strain(Dynamic)

Can be highCan be very high andmay be the limiting
factor• On-off fast actuators• Impactors• Long-stroke actuation (SPA
Motors)• Shutter• Fluid injection• Circuit breaker• Fast positioning• Long-stroke positioning

Dynamic
Sensing

Can be high(due to external
vibrations)

Negligible (Generated
voltage should bemonitored)• Electric generator• Force sensor• Energy Harvesting• Igniters• Force Sensing

Dynamic
Strain non
resonant

FUNCTIONS /USED AS

Table 3.a Applications, functions & working conditions

APPLICATIONS /USED FORCEDRATTECHNOLOGIES
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3.2.1. APPLICATIONS OPERATED UNDER STATIC CONDITIONSTILT MECHANISMS
As Amplified Piezoelectric Actuators (APA®) are rather ﬂat,they can be arranged in parallel. It is interesting either toincrease the force or for tilting applications (Fig. 3.a). In
this last case the ﬂat structure of APA® allows to place theiractuation axes close together to get a relatively large tilt
angle. This is shown with a first tilt mechanism TT50S
based on two APA50S actuators and producing an angulardisplacement of +/- 0.5° and a resonance frequency of1800 Hz. In this mechanism, the Finite Element Method
can be used to design ﬂexural
hinges (Fig. 3.b).
Using this possibility, standard
tilt or double tilt mechanisms
products have been designed
for optical deﬂection: TT60SM
and DTT35XS (see 5, page77), respectively based on
two APA60SM and four APA35XS
mounted with ﬂexural hinges .
Customised tilt mechanisms canalso be easily derived from otherstandard actuators. For instance,a space version of the DTT60SM
has been developed for Airbus
DS within the ATLID project (seeFig. 3.c). This mechanism has towithstand external vibrations andbenefits from the APA® properties.

to ensure the nano-resolution scanning motion of an
Atomic Force Microscope (AFM) under a severe
environment (see Fig. 3.e). Although operated under static
conditions, the ability of CTEC actuators to withstand large
vibrations thanks to their pre-stress allowed themechanism to pass vibration tests. It was launched in
2004 and run in 2014 when Rosetta reaches ChuryumovGerasimenko comete.
Another example of XYZ mechanism developed for an
optical application is given with Fig. 3.f. This mechanism isable to perform any stroke in the volume [-100,+100 µm]
× [-100,+100 µm] × [0.200 µm].
It is entirely based on standard
components. It combines astandard XY200M stage basedon 4 APA200M for centred XY
displacements (scanning
function) with a set of 3 APA200M
for Z displacements (focussing
function).

TRIPODS & HEXAPODSCTEC’s actuators have also beenused to build complex nanopositioning mechanisms such as
tripods, hexapods or 5 d-o-fmechanisms in the fields ofFig. 3.a: DTT batch
astronomy and space optics. For
example, CSEM (Switzerland)
and SENER (Spain) had to develop a tripod mechanism for
Another configuration to build tilts mechanisms has been
nano-positioning and stabilisation of the M5 mirror in thedesigned for actuation functions in Micro Aerial Vehicles
Extremely Large Telescop (ELT) of ESO. The mirror mass isfor ETZH (see Fig. 3.d). The complete mechanism ismore than 600 kg. Therefore this induces a static load but
monolithic and uses two APA® in a push-pull configuration.
also dynamic loads (due to possible earthquakes) have toThis allows deflection of up to 10°, with a weight of only
be added to the functional dynamic load. After a trade-off
0.35 gr.
analysis, CSEM and SENER have selected the APA®
technology. CTEC has then developed 3 customised
extremely-large actuators APA500XXL meeting these
XY & XYZ MICRO POSITIONING MECHANISMS
severe requirements (see Fig. 3.g).
Several XY or XYZ stages have been designed at CEDRATTECHNOLOGIES (CTEC) for various needs.
The customised XYZ smart mechanism for the MIDAS
instrument of ROSETTA space mission was developed
under an ESA/ESTEC contract, starting from standard
APA50S and PPA10M. The function of this mechanism is

Other examples of piezo actuators applications inmechanisms are given in:
cedrat-tec.com/technologies/actuators/piezo-mechanisms

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Products Catalogue Version 5.1 - Markets & Applications

ELECTROMAGNETS FOR FORCE
GENERATION
Customised electromagnets aredeveloped by CTEC to generate themaximum of force / torque in theminimum of volume / mass. Sucha feature is deemed essential foraerospace applications and thesesolenoids remain usual for static
operation.
Within a volume of 10 cm 3 andless than 90 grams, rotar yelectromagnets are capable ofproviding up to 10 degrees angle
with a torque higher than 160N.mm.
Such a design complies with ECSS
standard and this technology isdelivered as flight models for OrionESM mission.

ROTARY VOICE COIL MOTORS(RVCM)
Dedicated high per formance
voice coil motors are designed
using multi-physics simulations
skills, high performances material
knowledge and system integrationand qualification know-how.
RVCM is developed to equip the SCan
Assembly (SCA) of Meteosat Third
Generation (MTG) satellites. 20 yearsof operational lifetime are required
for this application. Typical stroke
achieves +/-15 degrees angle witha nominal torque of 0.4 N.m. Beyond
its ability to withstand environmental
requirements (thermal, vacuum,
vibration 30 Grms, shocks…), thismotor demonstrates high stabilityof the torque constant according toboth position and current. Its uniquebalanced design allows to reduceparasitic forces and eases theintegration of guiding system.

Fig. 3.b: Tilt-Translator TT50S (based on
2 APA50S actuators) and producing anangular displacement of +/- 0.5° anda resonance frequency of 1800 Hz.

Fig. 3.c: DTT60SM based on 4 APA60SMSG (courtesy of Airbus DS Sodern)Fig. 3.e: Midas Space Instrument(courtesy of ESA)
Fig. 3.d: Miniature Tilt-Translator
TT40uXS (courtesy of ETHZ)

Fig. 3.f: XYZ200M-SG stage for
IR Spectroscopy (courtesy of GES
Lab / Montpellier University)

Fig. 3.h: Brake solenoid flight modelFig. 3.g: APA500XXL for ELT
M5 mechanism (courtesy of
CSEM, NTE and ESO)

Fig. 3.i: RVCM flight modelCEDRATTECHNOLOGIES
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3.2.2. APPLICATIONS OPERATED UNDER DYNAMIC NON-RESONANT CONDITIONSFAST XY STAGES FOR SCANNING, STABILISATION...

ACTIVE FIXTURE USING MICA200M

Several OEM XY stages for fast micro-scanning andstabilisation are produced in series by CEDRATTECHNOLOGIES (CTEC).

A technological breakthrough has been achieved with a
new version of the MICA™. The MICA200M actuator and its
dedicated compact power electronics has been developedin the frame of the INTEFIX FP7 project to address the fieldof active fixture (Fig. 3.o). That application is challenging
since the MICA™ actuator’s response is used for both
vibration and deformation control during the machining of
low rigidity parts. Therefore a better controllability of theactuator is needed in terms of force along the stroke, andon a wider range of frequency including static control.

XY25XS stage (Fig. 3.j) uses parallel piezo actuation, whichis also used in XY200M products. This configuration is
optimal for fast motion and renders feasible new optical
functions. For example fast micro-scanning is highly
beneficial in defence infrared cameras to improve thecamera resolution. In this application the short responsetime of the actuators is used to perform a complex pattern
to allow image reconstruction from several pictures at a
rate of 100 Hz. Therefore the actuators are used underalmost impulse strain conditions. In addition, the XY stage
should operate in spite of external vibrations, the camera
being embedded in land, aerial and sea vehicles. Therefore
CTEC actuators’ performances in dynamics are suited tothis class of application.
Parallel magnetic actuation is another option when evenlarger strokes are needed. Fig. 3.k is a XY stage based on
small Moving Iron Controllable Actuators (MICA™) offering
2 mm × 2 mm stroke, designed for optical stabilisation.

SERVO PIEZO TOOLSThe Servo Piezo Tools (SPT) developed by CTEC can realise
both fast and precise machining: applications vary fromoval piston machining to aspherical lens machining.
For example, the SPT400MML (Fig. 3.l) prototype uses the
Amplified Piezoelectric Actuator (APA®) APA400MML toobtain a large and fast motion of the diamond tool (400µm
at more than 100Hz). The SPT400MML is arranged in acasing and dry air is used to expel dust from the casing.
It includes an Eddy Current proximity Sensor for position
control.

ACTIVE VIBRATION DAMPERS
When coupled to well suited driving and control electronics,
piezo actuators are excellent deemed candidates toactively damp the vibrations on a mechanical structure.
CTEC has already developed and set up several OEM
solutions based on APA® & Parallel Pre-stressed Actuators(PPA) for Active Control of Vibrations (ACV) on machine
tools (see Fig. 3.m), ski and medical robot (see also Fig.
3.n).

Actuators or systems for vibrations damping are alsoavailable upon request. Other examples of applications ofactive damping are given in:
cedrat-tec.com/technologies/mechatronic-systems/vibrationcontrol

VIBRATION GENERATOR OPERATINGIN FORCED VIBRATION MODE
Amplified Piezoelectric Actuators (APA®) and Parallel
Prestress Actuators (PPA) find several applications forvibration generation in forced vibration mode (below
resonance): APA® and PPA used in forced vibration mode
are typically used in machines for material mechanicaltesting, such as the lifetime test of Semicon silicon partsor films by stress cycling, or machines for vibration testingsuch as piezoelectric shakers (see Fig. 3.p).
Moving Iron Controllable Actuators (MICA™) are a newalternative for vibration testing. It offers more stroke (up to10mm) compared to electrodynamic shakers while being
much more compact.
Another range of industrial applications of this mode isthe vibration assistance to processes. Forced vibrations
provide a useful assistance in many processes such as
food cutting, glass cutting, engraving, machining (milling,
drilling…), extruding etc… Typically vibration assistance
improves the process speed and/or surface quality.
An example in the field of Vibration Assisted Machining(VAM) or Modulation Assisted Machining (MAM) resultsfrom the AVIBUS project coordinated by CTEC. From tests ofArts et Métiers ParisTech (ARTS) and CETIM, the Vibration
Assisted Drilling (VAD) tool holder of Fig. 3.q allows to
reduce the drilling time by a factor of 3.

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POWERFUL VIBRATIONSGENERATIONCTEC has enhanced standard
piezo actuators in order to addresscontinuous high energy vibration
generation. Firstly the preload of theactive component has been doubled
without any performance limitation.
Secondly, a dedicated encapsulation
technique combined with theuse of high temperature material
allow to dissipate and withstandheat generation. Thirdly, a newgeneration of Switching Amplifier,called SA, has been developed todrive these powerful actuators attheir maximum possible energy (see§8.1.4. Switching voltage amplifiers,
page 106).
Any APA® or PPA actuator can now
be supplied with an encapsulation
option and their preload can be
improved if required. As an example,
an encapsulated PPA80L (see Fig.
3.r and Fig. 3.s) has been driven
continuously at full stroke up to
1 000 Hz, whereas its standard
version does not exceeds 50 Hz.
These powerful piezo actuators arecommonly used in manufacturing
process for vibration assistance or
acoustic generation and operate
within harsh/humid environments.

Fig. 3.j: XY stage based on APA25XS
used for micro-scanning

Fig. 3.k: XY stage based on
MICA™ used for stabilisation

Fig. 3.l: Servo Piezo Tool SPT400MML

Fig. 3.m: Smart Tool based on
PPA60L (courtesy of IFW)

Fig. 3.n: An educational ACV
Kit, based on this technique isavailable as a standard productFig. 3.o: Active fixture using MICATM

Fig. 3.p: Piezoelectric shaker(courtesy of Sandia Lab)

Fig. 3.q: AVIBUS VAD tool holder

Fig. 3.r: From standard to encapsulated
piezo actuators: PPA801L to PPA80L-E

Fig. 3.s: Temperature riseat 235Hz, full stroke

Other examples of applicationsof forced vibrations using CTEC’s
products are given in:
cedrat-tec.com/technologies/
actuators/sonic-ultrasonic-generators

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3.2.3. APPLICATIONS OPERATED UNDER DYNAMIC RESONANT CONDITIONSPIEZO VIBRATORS OPERATING AT RESONANCE
CEDRAT TECHNOLOGIES (CTEC) Parallel Pre-stressed
Actuators (PPA) and Amplified Piezoelectric Actuators(APA®) are also successfully used in resonant mode forvibration generation at a fixed frequency in that case fullstroke is achieved with less than 10 V instead of 170 V in
quasi static conditions.
In some cases, special interfaces are useful, for example
the Ultrasonic Piezo Actuators (UPA) deriving from the
APA® have been developed to offer a more compact
solution than Langevin transducers for the generation ofultrasonic vibrations. UPA structures are the same as APA®
structures, but they are maintained on the side of the longaxis in order to decouple the support from the vibration
generation (free-free mode).
UPA are customised products finding applications inmachining (for example ultrasonic engraving) or in
ultrasonic piezo motors.

COMPRESSORS, EXPANDERS, PUMPS
Dynamic resonant conditions are used when the working
frequency is well-defined and low electrical power isneeded. These conditions perfectly fit with balanced

Fig. 3.t: View of an UltrasonicPiezo Actuator (UPA)

compressor, and pump applications, using low vibrationback to back linear reciprocators. Moving Iron Controllable
Actuators (MICA™) are well-suited for resonant conditions
since they feature high efficiency to provide high output
force, with low electrical input power. They feature also
ultra-long lifetime, using frictionless, and free of lubricant,flexure bearings. Custom output mechanical power can
range from 3 W to higher than 1000 W on demand,with housing designs featuring fluid leak tightness, biocompatibility.
Resonant MICA™ flexure bearings actuators are especiallyrelevant as pressure wave generators, or expanders insidehigh frequency Stirling machines, for wasted heat energy
recovery, refrigerators, and cryogenic coolers, as well as
positive displacement compressors, using read valves,
inside Rankine and Joules Thomson machines.

FOOD CUTTING
The actuator designed exhibits large stroke and highworking frequency which is particularly relevant for a
cutting function. The linear motion allows direct drive of the
cutting tools, leading to simplicity and noise reduction of
the whole system. Flexible guiding offer extended lifetime,increasing the intervals of maintenance in production.

Fig. 3.u: Moving cylinder MICATM
actuator for pump and compressor

Fig. 3.w: CAD integration of MICATM insideback to back balanced compressors

Fig. 3.v: Moving piston MICATM
actuators for pump and compressor

Fig. 3.x: Vibrating Food Cutter using MICATM

Products Catalogue Version 5.1 - Markets & Applications

3.2.4. APPLICATIONS OPERATED UNDER
DYNAMIC FORCE CONDITIONSPROOF-MASS ACTUATOR
A Proof-Mass Actuator aims at generating dynamic forces into a structure
to either excite vibrations in the structure (proof-mass shaker) or to damp
vibrations of the structure (proof-mass dampers).
CTEC piezoelectric proof-mass dampers are made of an APA®, a backmass fixed on one side of the actuator, and optionally some guiding
functions (Fig. 3.y). The second side of the actuator is fixed on the
structure. By reaction, because of mass inertia, dynamic forces can beproduced in the structure at the resonance frequency and above
resonance. In this condition, the Proof Mass Actuator may provide
dynamic forces up to the APA® blocked force.
Standard MICA™ actuators have been successfully integrated inside
milling machine, to perform active vibration damping in a proof massconfiguration. For such a configuration, MICA™ with flexural bearing (see§7.1. Moving Iron Controllable Actuator MICA™, page 92) is preferred.
Then there are different possibilities for the reaction masses. The
actuator can be fixed to the structure via its moving part, then the stator
plays the role of the reaction mass. Alternately, the actuator can be fixed
to the structure via its stator, then the moving part plays the role of thereaction mass. In that case, an additional mass is generally added to themoving part in order to tune the resonant frequency.

Fig. 3.y: PMA900M Proof Mass Actuator

Fig. 3.z: MICA 300CM proof-mass

This work has been performed in the frame of the DynXpert FP7 project“Factories of the Future” (see Fig. 3.aa). The main purpose of the MICA™
integration was to suppress the chatter occurring at different ranges offrequency. Standard MICA™ actuators are capable of providing forces up
to 1000 N, working at low to high frequency. The main advantages of
MICA™ actuators are the capabilities to be integrated in relatively small
allowed volumes for the requested force, and the capabilities to withstandharsh environment such as vibrations, shocks, and high ambient
temperature that can be found in machining tools. Derived from thissuccessful R&D activity, standard MICA-based Tunable Proof-Mass
Actuators are commercialised (see §7.3. Tunable proof mass actuators,
page 96).

Fig. 3.aa: Active vibration damping through MICATM

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3.2.5. APPLICATIONS OPERATEDUNDER IMPULSE CONDITIONSFAST & PRECISE VALVES
The well-known advantages (rapid response and precise positioning) of
Amplified Piezoelectric Actuators (APA®) have been used in valve designs
to obtain both rapid and precise-flow proportional valves.

Fig. 3.ab: Pneumatic piezo valve

Fig. 3.ac: Bench for testing pressure-regulation
piezo valve for ARIANE 6 launcher

A ﬁrst gas valve (see Fig. 3.ab) was manufactured using a small APA®
(APA120S) and was further driven with a switched ampliﬁer to get a highfrequency modulation. A frequency bandwidth higher than 400 Hz witha stroke of 100 µm has been measured. These properties can also be
used for gasoline injectors.
CEDRAT TECHNOLOGIES (CTEC) has already designed and developed
hydraulic piezo valves within the European project FP6 MESEMA. CTEC
is also providing space piezo valves under ESA contracts for the
propulsion of micro satellites or under CNES-ARIANE contracts. Using a
dedicated test bench (Fig. 3.ac), APA-based piezo valves (Fig. 3.ad), aredeveloped for fine pressure regulation for ARIANE 6 launcher. Such piezo
valves offer advantages to solenoid valves for example to reduce power
consumption. However solenoid valves are still developed by CTEC,
especially based on MICA™ actuators for large fast & precise flow control..
For speciﬁc designs of piezo valves, please contact CTEC or visit:
cedrat-tec.com/technologies/actuators/electro-fluidic-devices

LONG-STROKE ACTUATION WITH STEPPING PIEZOELECTRIC
ACTUATORS (SPA) PIEZO MOTOR
SPA are piezo motors for long stroke actuation whose principle andproduct characteristics are introduced in section §2.1.6. Stepping Piezo
Actuators SPA, page 19. An SPA is basically an Amplified Piezoelectric
Actuator (APA®) exploiting both slow and fast strains to get stick slip
effects. Thus the SPA uses the APA® under Impulse strain conditions.
Fig. 3.ad: Pressure-regulation APA-based
piezo valve for ARIANE 6 launcher

As a first consequence, the SPA takes advantage of the APA® pre-stressto demonstrate the following performances:• fast response time,• ability to withstand external vibrations,• robust structure (no dismounting during operation),• good resistance to transverse forces...
As a second consequence, all APA® offering good dynamic capabilities
can be used to make new SPA. Therefore new customised SPA can easily
be developed upon request from the large range of standard APA®.

Fig. 3.af: LSPA30uXS piezo motor

The LSPA30uXS (Fig. 3.af) is an example of customised miniature piezomotor developed for a MRI-compatible medical implant. It is based on
the SPA motor concept and the APA30uXS micro actuator. This motor isfully-non magnetic, passing MRI tests. Its mass is less than 1 gr.

Products Catalogue Version 5.1 - Markets & Applications

It performs stroke of 3 mm with a controllable speed from 0 to 70 mm/s.
The blocking force at rest is higher than 0.5 N while the actuation force
is higher than 0.2 N.
The SPA technology has received a Golden Micron award at MICRONORA
2008 micro technology fair because of its relevance for precision andminiaturisation positioning functions.
Examples of CTEC piezo motors and applications are given in:
cedrat-tec.com/technologies/actuators/piezo-motors-and-electronics

MULTI-AXIS ACTUATION WITH SPA PIEZO MOTOR
Multi degree of freedom (dof) mechanisms are widely required into microor macro manipulation fields as well as in optronics functions. Thanks totheir versatility and robustness, SPA motors can be combined to generatesuch multi-axis movement.
The patented Tripod ACtuator (TrAC) is a 3 degrees of freedom mechanism
offering +/-35° rotation around X and Y axis and a 10 mm Z translation
stroke into a low volume of Ø50×50 mm.
This large displacement capability is combined with a 3 mrad / 6 µm
fine positioning mode allowing to achieve micro-radian and nanometricpointing or positioning resolutions.
Watch our video: youtu.be/rsO9uqS6cbk

Fig. 3.ag: Tripod Actuator TraC

3.2.6. APPLICATIONS OPERATED UNDER
DYNAMIC SENSING CONDITIONSPIEZO GENERATORS & ENERGY HARVESTING
Piezo actuators can also be used as electric generators. When subjected
to an external source of vibration or to a shock, a piezo actuator produces
electrical energy.
Among different actuators, APA® are good candidates to perform sucha function with reliability and efﬁciency because they are pre-stressedand because their shell contributes to a favourable dynamic stress
distribution.
It has been demonstrated for example that a small APA® encapsulated
within a frame box can produce 4mW power at 400 Hz (see Fig. 3.ah).
CTEC can develop customised piezo generators using its rangeof standard piezo actuators. Examples of other piezo harvesting
applications are given in:
cedrat-tec.com/technologies/mechatronic-systems/energy-harvestingFig. 3.ah: Energy piezo harvester
based on APA50XS actuator

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3.3. ADDITIONAL TECHNOLOGICAL SOLUTIONSThis section presents technological solutions that can be proposed inaddition to technological solutions introduced in section §3.1. Market
overview, page 43 or to standard products described in chapters 4,
page 57 to 7, page 91.

3.3.1. HOLLOW PARALLEL PRESTRESSED ACTUATOR
HPPA

Fig. 3.ai: HPPA for the first European space Lidar,
Aladin / Aeolus (courtesy of Galileo Avionica)

CEDRAT TECHNOLOGIES (CTEC) has delivered some annular multilayers
piezo ceramics pre-stressed (preloaded) by an external elastic frame.
This structure called Hollow Parallel Prestressed Actuator (HPPA) allows
to increase the life time and reliability of the piezo rings under severe
environment (high level of vibrations) and in dynamic applications.
It enables to reach very high frequencies, with a resonance over kHz.
Several HPPA, including flight models, have been delivered for various
space missions.

3.3.2. EXTREMELY AMPLIFIED ACTUATORSThe Amplified Piezoelectric Actuators (APA®) shape is a highly effective
amplification mechanism offering a high efficiency. However, it issometimes required to achieve even larger displacements.

Fig. 3.aj: Two-stages amplified and monolithic actuator
designed with SOLEIL for the SixS beamline

A second stage amplification is then a good solution to build anextremely amplified actuator. Very compact actuators can provide
high displacement, with amplification ratio up to 40 or more. Careful
design is needed with these actuators to preserve acceptable stiffness
and positioning stability. The Fig. 3.aj shows a two-stages amplified
and monolithic actuator developed for a synchrotron beam shaping
mechanism, with a stability under the micron, for a displacement of
400 µm.

Products Catalogue Version 5.1 - Markets & Applications

3.3.3. APPLICATIONS REQUIRING A HIGH STABILITYIN CLOSED LOOP
Many applications require long-term position stability, which relates
to the notion of absolute precision over time. CTEC has demonstrated
nanometric position stability of a closed-loop piezo-mechanism withintegrated strain gages sensors. This technology opens a wide rangeof new possibilities for industrial, aeronautical, and space applications.
In the nanometric range, contributions that are usually considerednegligible become main contributors. Dedicated test equipment has
been set-up in order to perform high precision instrumentation ofsystems, based on a high precision laser interferometer. Measurements
are done in a primary vacuum chamber and with thermal control.
The resolution can reach the nanometric range, with a tested 500 hours
stability of ±10 nm (see Fig. 3.ak)

Fig. 3.ak: Stability test of two weeks long

3.3.4. MECHANICALLY-DAMPED AMPLIFIEDPIEZOELECTRIC ACTUATORS APA®
In some applications (operations under external vibrations, impulse
response), it is interesting to use an actuator that displays a low
mechanical Quality factor. A low Q factor reduces the amplification atresonance and the stress levels.
The large range of APA® can be mechanically damped by adding someelastomer parts in the actuator. A Q factor below 5 is achievable.
Please contact CTEC to customise Mechanically Damped APA® (MDoption) as a function of your environmental parameters (temperature,vibration level... ).

Fig. 3.al: View of an APA400M-MD

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For more information on this chapter,
please visit these pages:
cedrat-tec.com/products/actuators/apa
cedrat-tec.com/products/actuators/parallel-pre-stressed-actuators
cedrat-tec.com/technologies/actuators/piezo-actuators-and-electronics

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Products Catalogue Version 5.1 - Piezo actuators

4. PIEZO ACTUATORS
4.1. SELECTION GUIDE
4.1.1. INTRODUCTION
CEDRAT TECHNOLOGIES (CTEC) offers a wide range of commercially off-the-shelf actuators:
Amplified Piezoelectric Actuators (APA® ), Parallel Pre-Stressed Actuators (PPA) and conventional
Multilayer Actuators (MLA). These actuators benefit from 20 years of space heritage andindustrialisation efforts. Several options are available and most of the actuator’s functional
properties, mechanical or electrical interfaces can be modified to meet the customer’s needs.
Please do not hesitate to contact CTEC for more information about an actuator’s additionalfeatures.

Type ofactuator

Stroke in
µm

Serie

Option(s)Fig. 4.a: Products naming

RANGE OF PRODUCTBLOCKED FORCE MIN-MAX

STROKE MIN-MAX

APA XXS

3.2

130

APA uXS

2.7

34

APA XS

16 - 2752 - 66

APA S

46 - 130

75 - 140

APA SM

140 - 260

54 - 77

APA M

18 - 240

130 - 790

APA MML78 - 830

100 - 650

APA ML540 - 3300

65 - 300

APA L

62 - 1 300

230 - 2000

APA XL770 - 1 400

590 - 1 100

PPA M

850

8.3 - 38

PPA L

3500

44 - 130

PPA XL

7000

43 - 130

MLA

400 - 9 300

10 - 20

Table 4.a APA® and PPA blocked force and stroke
The technical information on this chapter is not contractualand can be changed without prior notice.

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4.1.2. MECHANICAL INTERFACE OPTIONSVAC - VACUUM
UHV - ULTRA HIGH VACUUM

TH - THREADED HOLE

Our actuators can be compatible with vacuum environment,with one of these two options.

The actuator has two identical mechanical interfaces: aflat interface with a centred threaded hole.

FI - FLAT INTERFACE
The actuator has two identical flat interfaces that can bebonded.

H - HOLE
The actuator has two identical mechanical interfaces: aflat interface with a non threaded hole.

SI - SPECIFIC INTERFACE
In order to make the mechanical integration of its actuators
easier as OEM products, Cedrat Technologies (CTEC) can
design and machine a Specific Interface on top of its
actuators to meet the customer’s needs.For any question
regarding mechanical integration, please contact CTEC.

4.1.3. STANDARD OPTIONS
SG - STRAIN GAUGESThe SG option consists in gluing strain gauges to the piezo
ceramics stack . This allows monitoring the ceramics strain
and thus the displacement of the piezo actuator (See Fig.
4.b and 9.2, page 122). Standard SG is connected via aflex cable; other plugs are available on request. The SG
signal is conditioned by the SG75 electronic board
integrated in a rack amplifier. Adding a digital controller
board allows a closed loop control.

NM - NON MAGNETIC
With this option the actuator is made of non-magnetic (NM)material: it does not disturb any external magnetic field
and is also completely insensitive to an external appliedmagnetic field.
Some properties (e.g. thermo-mechanical behaviour,
mass, width, characteristics) may differ from the standard
actuator’s features.
Note: NM and TC options are not compatible.

The VAC option consists in adapting the integration process
to avoid the presence of any dust and make the actuator
compatible with vacuum environment. The VAC option is
generally used till down 10-6 mbar.
The UHV option goes further with a specific integration
process and the adaptation of materials used. The UHV
option is compatible with vacuum down to 10-9 mbar. It
enables low outgasing or proximity of optical components.
Would you have any specific constraints, as for space
projects, please contact us with your requirements.

TS - THERMOCOUPLE SENSOR
For certain dynamic applications, it may be necessary tofollow up the self heating of the piezo ceramic in order toavoid overheating and damages.
For such application cases, we developed a dedicatedoption where we bond a thermocouple sensor on the piezo
ceramic in order to monitor its inner temperature.

4.1.4. SPECIFIC VERSIONSCFRP - CARBON FIBRE REINFORCED POLYMER
The CFRP option relates to the use of a CFRP composite
instead of metal to make the APA® shell.
This change leads to several advantages: significant mass
reduction, higher bandwidth, lower Q-factor, much lower
thermal expansion
This option results of a collaboration with ONERA
considering helicopter flap applications (See Fig. 4.c).

HT - HIGH TEMPERATURE
The HT option refers to special piezo material andprocesses (bonding) that can be used to build High
Temperature piezoelectric actuators.

TC - THERMO-COMPENSING
The TC option is a special construction which allows the
improvement of the behaviour within a wide temperature
range, especially at the liquid nitrogen temperature

Products Catalogue Version 5.1 - Piezo actuators(77°K); Its objective is to reduce the actuator coefficientof thermal expansion.
Note: NM and TC options are not compatible.

G - GUIDING
To obtain a better dynamic movement, it is possible to
add a flexible guiding to the actuator’s shell. This can be
added at the application integration level or designed
monolithically with the shell. Please contact CTEC todiscuss your application.

Fig. 4.b: APA500XL-SGE - ENCAPSULATION
Designed encapsulation with cooling systems overcome
overheating limitation. Compared to regular version of theactuator the driving frequency has increased 20 times
for encapsulated actuator with air cooling system. The
encapsulated actuator benefits from heat sinking structure
and without air cooling system can be used at frequency
that is nearly 5 times higher compared to regular actuator(See Fig. 4.d).

Fig. 4.c: ECP test bench for APA500L-CFRP-ECSECP - EDDY CURRENT PROBE
The ECP option refers to an APA® equipped with an ECP
sensor. The ECP sensor providing a nanometric resolution
and a direct measurement of the displacement of thehead of the actuator, this option gives the best precision
possible. The ECP sensor signal is monitored with the
ECS75 conditioner board (See Fig. 4.e and chapter 9.3,
page 124).

Fig. 4.d: High temperature encapsulation on PPA80L-E

MD - MECHANICAL DAMPING (PRELIMINARY)
The MD option consists in added elastomeric parts inside
the APA®. This option provides damping and lowers the
Q-factor at resonance (see chapters 3.2.3, page 50 and
3.3.4, page 55). This also reduces overshoot in on-off
applications and improves resistance to external vibration.
This option results of R&T works for CNES.

Fig. 4.e: Test bench for APA2000L

SV - SPECIFIC VERSION
In some cases, the change of mechanical interfaces or the
piezo components on the shell materials leads to amodification of the functional properties. In that case, theSpecific Version of an existing standard actuator is called
the SV option. For any question regarding mechanicalintegration, please contact CTEC (See Fig. 4.f).
Fig. 4.f: Specific Version Twin Amplified
Piezoelectric Actuator APA®

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4.2. AMPLIFIED PIEZOELECTRIC ACTUATORS APA®

4.2.1. APA® UXS & XXS SERIES
Some applications of APA® uXS and XXS are:
• Earing implants• Actuation in Micro Aerial Vehicle• Energy harvester for pacemaker• Micro electro optical systems> See APA30UXS full datasheet

Fig. 4.g: APA150XXS> See APA150XXS full datasheet

PARAMETER

Nominal stroke
Blocked force
Stiffness
Resolution (b.1)
Force limit (0-peak) (b.2)
Free - Free resonance frequency
Blocked - free resonance frequency
Thermomechanical behaviour
Voltage range
Capacitance
HeightLengthWidth (incl. Wedges, wires)
Mass (excl. Wires)
Available options (b.4)
Specific versions (b.5)
Available interfaces (b.6)

UNIT

APA30UXS (B.3)

APA150XXS

µm
N
N/µm
nm
N
Hz
Hz
µm/K
V
µF
mm
mm
mm
g

34
3.7
0.11
1.9
7.5
25 000
4 800
0.33

130
3.2
0.024
7.4
2.2
3 800
1 100
1.6
-20 … 150

0.043
4.0
8.6
5.0
0.15

0.18
4.5
14
9.0
1.3
VAC
TC
FI H

Table 4.b Characteristics of APA® uXS and XXS series

b.1 With amplifier SNR of 85dB
b.2 External on-axis pulling or pushing force limit. Inertial forces should be assimilated as external forces.
b.3 Non magnetic configuration only
b.4 Refer to §4.1.3. Standard options, page 58
b.5 Refer to §4.1.4. Specific versions, page 58
b.6 Refer to §4.1.2. Mechanical interface options, page 58

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4.2.2. APA® XS SERIES
Some applications with APA® XS are:
• Micro optical mechanisms• Micro controllable dynamic valves• Space qualified micro tip tilts• Miniature brakes> See APA35XS full datasheet
Fig. 4.h: APA35XS> See APA50XS full datasheet

PARAMETER

Nominal stroke
Blocked force
Stiffness
Resolution (c.1)
Force limit (0-peak) (c.2)
Free - Free resonance frequency
Blocked - free resonance frequency
Thermomechanical behaviour
Voltage range
Capacitance
HeightLengthWidth (incl. Wedges, wires)
Mass (excl. Wires)
Available options (c.3)
Specific versions (c.4)
Available interfaces (c.5)

UNIT

APA35XSAPA50XS

µm
N
N/µm
nm
N
Hz
Hz
µm/K
V
µF
mm
mm
mm
g

52
27
0.52
2.9
37
18 000
3 900
0.69

66
16
0.24
3.7
13
12 0002 700
0.83-20…150
0.30

5.5
13
9.0
2.0
SG NM VAC

NM VACTC
TH FI H

Table 4.c Characteristics of APA® XS series

c.1
c.2
c.3
c.4
c.5

4.7
13

With amplifier SNR of 85dB
External on-axis pulling or pushing force limit. Inertial forces should be assimilated as external forces.
Refer to §4.1.3. Standard options, page 58
Refer to §4.1.4. Specific versions, page 58
Refer to §4.1.2. Mechanical interface options, page 58

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4.2.3. APA® S SERIES
Some applications with APA® S are:• Shaking powder for X-ray diffraction• Optical stabilization for embedded cameras• Space qualified optical stages• Nano-indentation> See APA60S full datasheet> See APA120S full datasheet
Fig. 4.i: APA60S

PARAMETER

Nominal stroke
Blocked force
Stiffness
Resolution (d.1)
Force limit (0-peak) (d.2)
Free - Free resonance frequency
Blocked - free resonance frequency
Thermomechanical behaviour
Voltage range
Capacitance
HeightLengthWidth (incl. Wedges, wires)
Mass (excl. Wires)
Available options (d.3)
Specific versions (d.4)
Available interfaces (d.5)

UNIT

APA60S

APA120S

µm
N
N/µm
nm
N
Hz
Hz
µm/K
V
µF
mm
mm
mm
g

75
130
1.7
4.2
120
13 000
2 900
1.1

140
46
0.33
7.9
32
7 200
1 300
1.7
-20 ... 150
1.1

15
29

13
29
9.0

8.5

7.2
SG NM VAC TS
HT TC
TH FI H

Table 4.d Characteristics of APA® S series

d.1 With amplifier SNR of 85dB
d.2 External on-axis pulling or pushing force limit. Inertial forces should be assimilated as external forces.
d.3 Refer to §4.1.3. Standard options, page 58
d.4 Refer to §4.1.4. Specific versions, page 58
d.5 Refer to §4.1.2. Mechanical interface options, page 58

63

Products Catalogue Version 5.1 - Piezo actuators

4.2.4. APA® SM SERIES
Some applications with APA® SM are:
• Shock energy harvester in wireless switches• Material Stress cycling• Injectors> See APA40SM full datasheet> See APA60SM full datasheet
Fig. 4.j: APA60SM

PARAMETER

Nominal stroke
Blocked force
Stiffness
Resolution (e.1)
Force limit (0-peak) (e.2)
Free - Free resonance frequency
Blocked - free resonance frequency
Thermomechanical behaviour
Voltage range
Capacitance
HeightLengthWidth (incl. Wedges, wires)
Mass (excl. Wires)
Available options (e.3)
Specific versions (e.4)
Available interfaces (e.5)

UNIT

APA40SM

APA60SM

µm
N
N/µm
nm
N
Hz
Hz
µm/K
V
µF
mm
mm
mm
g

54
260
4.9
3.0
170
15 000
4 100
0.79

77
140
1.8
4.3
110
10 0002 800
1.1-20 ... 150
1.1

15
27

13
27
12

11

10
SG VAC TS
HT TC
TH FI H

Table 4.e Characteristics of APA® SM series

e.1 With amplifier SNR of 85dB
e.2 External on-axis pulling or pushing force limit. Inertial forces should be assimilated as external forces.
e.3 Refer to §4.1.3. Standard options, page 58
e.4 Refer to §4.1.4. Specific versions, page 58
e.5 Refer to §4.1.2. Mechanical interface options, page 58

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4.2.5. APA® M SERIES
Some applications with APA® M are:• Fast X-Ray vacuum compatible shutters• Dynamic valves• Laser cavity tuning• Miniature Active flaps for aero vehicles> See APA100M full datasheet> See APA150M full datasheet> See APA200M full datasheet

PARAMETER

Nominal stroke
Blocked force
Stiffness
Resolution (f.1)
Force limit (0-peak) (f.2)
Free - Free resonance frequency
Blocked - free resonance frequency
Thermomechanical behaviour
Voltage range
Capacitance
HeightLengthWidth (incl. Wedges, wires)
Mass (excl. Wires)
Available options (f.3)
Specific versions (f.4)
Available interfaces (f.5)

Fig. 4.k: APA150M

UNIT

APA100M

APA150M

APA200M

µm
N
N/µm
nm
N
Hz
Hz
µm/K
V
µF
mm
mm
mm
g

130
240
1.9
7.0
150
8 000
1 900
1.5

190
130
0.68
10
98
5 000
1 300
2.0
-20…150
2.2
22
55
9.0
17
SG NM VAC TS
ECP HT TC G E
TH FI H

240
87
0.37
13
56
4 600
910
2.4

25

20

Table 4.f Characteristics of APA® M series

f.1
f.2
f.3
f.4
f.5

With amplifier SNR of 85dB
External on-axis pulling or pushing force limit. Inertial forces should be assimilated as external forces.
Refer to §4.1.3. Standard options, page 58
Refer to §4.1.4. Specific versions, page 58
Refer to §4.1.2. Mechanical interface options, page 58

17

16

65

Products Catalogue Version 5.1 - Piezo actuators

4.2.6. SUPER APA® M SERIES
Some applications with super amplified APA® M are:• Clamping in wire feeding system• Inverted microscope positionner• Haptic technology feedback for display panels• Energy harvesters> See APA400M full datasheet> See APA600M full datasheet

Fig. 4.l: APA400M> See APA900M full datasheet

PARAMETER

Nominal stroke
Blocked force
Stiffness
Resolution (g.1)
Force limit (0-peak) (g.2)
Free - Free resonance frequency
Blocked - free resonance frequency
Thermomechanical behaviour
Voltage range
Capacitance
HeightLengthWidth (incl. Wedges, wires)
Mass (excl. Wires)
Available options (g.4)
Specific versions (g.5)
Available interfaces (g.6)

UNIT

APA400M

APA600M

APA900M (G.3)

µm
N
N/µm
nm
N
Hz
Hz
µm/K
V
µF
mm
mm
mm
g

460
34
0.07
26
21
1 800
420

550
24
0.043
31
16
1 300
320

790
18
0.023
44
1.7
1 100
260
7.8

4.8
-20…150
2.2
13
49
12
14

13
48
15
SG VAC TSHT TC G E
TH FI H
Table 4.g Characteristics of super APA® M series

g.1 With amplifier SNR of 85dB
g.2 External on-axis pulling or pushing force limit. Inertial forces should be assimilated as external forces.
g.3 Use limited to quasistatic operations
g.4 Refer to §4.1.3. Standard options, page 58
g.5 Refer to §4.1.4. Specific versions, page 58
g.6 Refer to §4.1.2. Mechanical interface options, page 58

10
49
12
VAC TS

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4.2.7. APA® MML SERIES
Some applications with APA® MML are:
• Active stabilisation of a watt balance• High frequency shakers• Elasto MRI• Long range cavity modulation in interferometers> See APA100MML full datasheet> See APA400MML full datasheet> See APA600MML full datasheet

PARAMETER

Nominal stroke
Blocked force
Stiffness
Resolution (h.1)
Force limit (0-peak) (h.2)
Free - Free resonance frequency
Blocked - free resonance frequency
Thermomechanical behaviour
Voltage range
Capacitance
HeightLengthWidth (incl. Wedges, wires)
Mass (excl. Wires)
Available options (h.4)
Specific versions (h.5)
Available interfaces (h.6)

Fig. 4.m: APA400MML

UNIT

APA100MML (H.3)

APA400MML

APA600MML

µm
N
N/µm
nm
N
Hz
Hz
µm/K
V
µF
mm
mm
mm
g

100
830
8.3
5.6
510
6 500
1 700
0.60

360
180
0.52
20
150
2 800
630
3.8
-20…150
6.3
24

650
78
0.12
37
47
1 500
320
7.9

58
85
76

17
78

12
48
SG VAC TS
ECP HT TC G E
TH FI H

Table 4.h Characteristics of APA® MML series

h.1 With amplifier SNR of 85dB
h.2 External on-axis pulling or pushing force limit. Inertial forces should be assimilated as external forces.
h.3 Preliminary data
h.4 Refer to §4.1.3. Standard options, page 58
h.5 Refer to §4.1.4. Specific versions, page 58
h.6 Refer to §4.1.2. Mechanical interface options, page 58

41
HT TC G E

67

Products Catalogue Version 5.1 - Piezo actuators

4.2.8. APA® ML SERIES
Some applications with APA® ML are:
• Active control of vibration on medical robots• High frequency shakers• Fretting fatigue testing• Space qualified positionner> See APA95ML full datasheet
Fig. 4.n: APA120ML> See APA120ML full datasheet> See APA200ML full datasheet> See APA300ML full datasheet

PARAMETER

Nominal stroke
Blocked force
Stiffness
Resolution (i.1)
Force limit (0-peak) (i.2)
Free - Free resonance frequency
Blocked - free resonance frequency
Thermomechanical behaviour
Voltage range
Capacitance
HeightLengthWidth (incl. Wedges, wires)
Mass (excl. Wires)
Available options (i.4)
Specific versions (i.5)
Available interfaces (i.6)

UNIT

APA95ML

APA120ML

APA200ML (I.3)

APA300ML (I.3)

µm
N
N/µm
nm
N
Hz
Hz
µm/K
V
µF
mm
mm
mm
g

99
2 100
21
5.6
1 100
6 500
2 100
1.6

120
1 500
12
6.7
910
5 800
1 900
1.7

220
780
3.6
12
470
4 200
1 000
1.9

300
540
1.8
17
1 700
3 100
760
3.3

34
79

30
79

120

110

-20 ... 150
13
60
80

45
79

160

160

23
SG VAC TSECP CFRP TC G E
TH FI H

Table 4.i Characteristics of APA® ML series

i.1
i.2
i.3
i.4
i.5
i.6

With amplifier SNR of 85dB
External on-axis pulling or pushing force limit. Inertial forces should be assimilated as external forces.
Preliminary data
Refer to §4.1.3. Standard options, page 58
Refer to §4.1.4. Specific versions, page 58
Refer to §4.1.2. Mechanical interface options, page 58

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4.2.9. APA® L SERIES
Some applications with APA® L are:
• Helicopter flaps• High frequency shakers• Material stress cycling• Mirror positioning in telescopes & instruments> See APA230L full datasheet> See APA500L full datasheet

Fig. 4.o: APA500L> See APA1000L full datasheet> See APA1500L full datasheet> See APA2000L full datasheet

PARAMETER

Nominal stroke
Blocked force
Stiffness
Resolution (j.1)
Force limit (0-peak) (j.2)
Free - Free resonance frequency
Blocked - free resonance frequency
Thermomechanical behaviour
Voltage range
Capacitance
HeightLengthWidth (incl. Wedges, wires)
Mass (excl. Wires)
Available options (j.4)
Specific versions (j.5)
Available interfaces (j.6)

UNIT

APA230L

APA500L

APA1000L

APA1500L

APA2000L (J.3)

µm
N
N/µm
nm
N
Hz
Hz
µm/K
V
µF
mm
mm
mm
g

230
1 300
5.8
13
910
3 100
860
3.6

510
580
1.1
29
430
2 000
460
6.7

1 500
99
0.067
83
72
720
140
18

2000
62
0.031
110
21
520
87
21

85

55
150
16
200

870
350
0.40
49
110
1 300
290
11
-20 ... 150
26
35

280

190
SG NM VAC TS
ECP HT CFRP TC G E
TH FI H

Table 4.j Characteristics of APA® L series

j.1
j.2
j.3
j.4
j.5
j.6

With amplifier SNR of 85dB
External on-axis pulling or pushing force limit. Inertial forces should be assimilated as external forces.
Preliminary data
Refer to §4.1.3. Standard options, page 58
Refer to §4.1.4. Specific versions, page 58
Refer to §4.1.2. Mechanical interface options, page 58

30

27
140
20

140

130

ECP HT TC G E

69Products Catalogue Version 5.1 - Piezo actuators

4.2.10. APA® XL SERIES
Some applications with APA® XL are:• High frequency shakers• Fretting Fatigue testing• Positioning of heavy loads• Force Testing> See APA500XL full datasheet

Fig. 4.p: APA1000XL> See APA1000XL full datasheet

PARAMETER

Nominal stroke
Blocked force
Stiffness
Resolution (k.1)
Force limit (0-peak) (k.2)
Free - Free resonance frequency
Blocked - free resonance frequency
Thermomechanical behaviour
Voltage range
Capacitance
HeightLengthWidth (incl. Wedges, wires)
Mass (excl. Wires)
Available options (k.3)
Specific versions (k.4)
Available interfaces (k.5)

UNIT

APA500XL

APA1000XL

µm
N
N/µm
nm
N
Hz
Hz
µm/K
V
µF
mm
mm
mm
g

590
1 400
2.4
33
1 100
1 500
350
7.9

1 100
770
0.70
62
640
1 000
210
14
-20 ... 150
77

82

57
210
25

650

600
SG NM VAC TSECP CFRP TC G E
TH FI H

Table 4.k Characteristics of APA® XL series

k.1 With amplifier SNR of 85dB
k.2 External on-axis pulling or pushing force limit. Inertial forces should be assimilated as external forces.
k.3 Refer to §4.1.3. Standard options, page 58
k.4 Refer to §4.1.4. Specific versions, page 58
k.5 Refer to §4.1.2. Mechanical interface options, page 58

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4.3. MULTI-LAYER ACTUATORS MLA SERIESThe Multi Layer Actuators MLA are non pre-stressed low
voltage piezo ceramics. As a consequence, they are notsuited to high level dynamic operations.
• Strain Gauges SG can be added on MLA upon request.
• Wired connections are secured through a tube shrink.
• MLA can be driven by CEDRAT TECHNOLOGIES (CTEC)
linear amplifiers.
Expertise of on MLA results from several space evaluation
programs performed for CNES and ESA on different types
of MLA.

PARAMETER

Nominal stroke
Blocked force
Stiffness
Resolution (l.1)
Free - Free resonance frequency
Thermomechanical behaviour
Voltage range
Capacitance
HeightWidth (incl. Wedges, wires)
Mass (excl. Wires)
Available options (l.2)

UNIT

µm
N
N/µm
nm
Hz
µm/K
V
µF
mm
mm
g

Fig. 4.q: MLA 5×5×20

2×5×10

5×5×10

5×5×2014×14×20

20
4 700
235
1.1

9 300
465

10
400
40

1 100
110

55

0.56
130 000
1.0
0.22
2.0
0.8

60 000120 000
2.0-20 ...150
1.2

0.55
5.0
9.0
1.9

Table 4.l Characteristics of MLA series

l.1 With amplifier SNR of 85 dB
l.2 Refer to §4.1.3. Standard options, page 58

10×10×20

3.8
SG VAC

4.4
10.0
16.0
15.0

8.7
14.0
20.0
30.0

71

Products Catalogue Version 5.1 - Piezo actuators

4.4. PARALLEL PRE-STRESSED ACTUATORS PPA
4.4.1. PPA M SERIES
Some applications with PPA M are:• Vibration assistance• Needle vibrator in a space Atomic Force Microscope• Active deformation of mirror in telescopes• Ultrasonic injection> See PPA10M full datasheet> See PPA20M full datasheet> See PPA40M full datasheet
Fig. 4.r: PPA10M

PARAMETER

Nominal stroke
Blocked force
Stiffness
Resolution (m.1)
Force limit (0-peak) (m.2)
Free - Free resonance frequency
Blocked - free resonance frequency
Thermomechanical behaviour
Voltage range
Capacitance
HeightLengthWidth (incl. Wedges, wires)
Mass (excl. Wires)
Available options (m.3)
Specific versions (m.4)
Available interfaces (m.5)

UNIT

PPA10M

PPA20M

PPA40M

µm
N
N/µm
nm
N
Hz
Hz
µm/K
V
µF
mm
mm
mm
g

8.3

20
850
44
1.1
500
39 000
20 0000.06-20 … 150
1.1
28
10
9
12
SG NM VAC TS
HT TC ETH FI H

38

100
0.47
62 00032 000
0.07
0.55
18

6

Table 4.m Characteristics of PPA M series

m.1 With amplifier SNR of 85 dB
m.2 External on-axis pulling or pushing force limit. Inertial forces should be assimilated as external forces
m.3 Refer to §4.1.3. Standard options, page 58
m.4 Refer to §4.1.4. Specific versions, page 58
m.5 Refer to §4.1.2. Mechanical interface options, page 58

222.1
23 000
11 000
0.04
2.2
48

25

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4.4.2. PPA L SERIES
Some applications with PPA L are:
• Active control of vibration• Oval piston machining• Heavy load positioning> See PPA40L full datasheet> See PPA60L full datasheet> See PPA80L full datasheet> See PPA120L full datasheet
Fig. 4.s: PPA80L

PARAMETER

Nominal stroke
Blocked force
Stiffness
Resolution (n.2)
Force limit (0-peak) (n.3)
Free - Free resonance frequency
Blocked - free resonance frequency
Thermomechanical behaviour
Voltage range
Capacitance
HeightLengthWidth (incl. Wedges, wires)
Mass (excl. Wires)
Available options (n.4)
Specific versions (n.5)
Available interfaces (n.6)

UNIT

PPA40L

PPA60L

PPA80L

PPA120L (N.1)

µm
N
N/µm
nm
N
Hz
Hz
µm/K
V
µF
mm
mm
mm
g

44

67

85

130

41
4.8

27
7.3

8 700
4 700
0.09

6 300
3 300
0.05

18
97

26
140

120
140
SG NM VAC TS
HT TC ETH FI H

190

3 500
80
2.5

52
3.8

15 0008 300
0.13

11 000
6 000
0.11

8.8
57

13
77

1 500

-20 … 150

24
18
92

Table 4.n Characteristics of PPA L series

n.1 Preliminary data
n.2 With amplifier SNR of 85 dB
n.3 External on-axis pulling or pushing force limit. Inertial forces should be assimilated as external forces
n.4 Refer to §4.1.3. Standard options, page 58
n.5 Refer to §4.1.4. Specific versions, page 58
n.6 Refer to §4.1.2. Mechanical interface options, page 58

73

Products Catalogue Version 5.1 - Piezo actuators

4.4.3. PPA XL SERIES
Some applications with PPA XL are:• Stabilisation of heavy loads in precision machine tool
• Fretting Fatigue testing• High Frequency Shakers> See PPA40XL full datasheet> See PPA80XL full datasheet> See PPA120XL full datasheet

Fig. 4.t: PPA80XL

PARAMETER

Nominal stroke
Blocked force
Stiffness
Resolution (o.1)
Force limit (0-peak) (o.2)
Free - Free resonance frequency
Blocked - free resonance frequency
Thermomechanical behaviour
Voltage range
Capacitance
HeightLengthWidth (incl. Wedges, wires)
Mass (excl. Wires)
Available options (o.3)
Specific versions (o.4)
Available interfaces (o.5)zUNIT

PPA40XL

PPA80XLPPA120XL

µm
N
N/µm
nm
N
Hz
Hz
µm/K
V
µF
mm
mm
mm
g

43

90
7 000
78
5.1
2 900
8 700
4 600
0.12
-20 … 150
34
100
30
30
320
SG NM VAC TS
HT TC ETH FI H

130

160
2.4
3 300
14 000
8 000
0.16
17
60

250

Table 4.o Characteristics of PPA XL series

o.1 With amplifier SNR of 85 dB
o.2 External on-axis pulling or pushing force limit. Inertial forces should be assimilated as external forces
o.3 Refer to §4.1.3. Standard options, page 58
o.4 Refer to §4.1.4. Specific versions, page 58
o.5 Refer to §4.1.2. Mechanical interface options, page 58

54
7.3
2 900
6 200
3 300
0.08
51
140

380

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4.5. CUSTOMISED PIEZO ACTUATORSCEDRAT TECHNOLOGIES (CTEC) has developed two whole
ranges of off the shelf piezo actuators: APA® and PPA.
However, if you are looking for a specific configuration you
couldn’t find in the previous pages, CTEC design office has
the capability to study a new design and realise the newgeometry.

Customisation may also consist in adding a marking,adapting the mechanical interfaces, withstanding a harshenvironment or integrating an actuator in your mechanism.
Don’t hesitate to contact us at actuator@cedrat-tec.com foryour new development.

Fig. 4.u: APA500L-Twin with specific interface and wiringFig. 4.v: APA200MML-E

Fig. 4.w: APA500L-E-HT

Fig. 4.x: Specific APA® with stack encapsulation

Products Catalogue Version 5.1 - Piezo actuators

75

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compact dynamic precise

For more information on this chapter,
please visit these pages:
cedrat-tec.com/products/actuators/mechanisms
cedrat-tec.com/technologies/actuators/piezo-mechanisms

Products Catalogue Version 5.1 - Piezo mechanisms

5. PIEZO MECHANISMS
5.1. SELECTION GUIDECEDRAT TECHNOLOGIES (CTEC) compact and dynamic actuators are used to build mechanisms,
which realise advanced mechatronic functions, offer easy interfaces and can integrate opticalcomponents.
All the PPA or APA® actuators (see chapter 4, page 57) can be used to build translation stages,
tilt translators or shutters. These mechanisms can integrate position sensors (see chapter 9,
page 121) for closed loop control.
Different product lines are available off-the-shelf:• X: single axis guided stage, with reduced out-of-plane Y and Z displacements,• XY: two axis stage, with reduced out-of-plane Z displacement,• XYZ: three axis stage,• TT: single axis Tilt Translator,• DTT: Double (two axis) Tilt Translator,• FPS: Fast Piezo Shutter.
These mechanisms can be driven either by the benchtop electronics or by embedded drivers.
Refer to chapter §8. Drive Electronics & Controllers, page 101.
Please do not hesitate to take a look at our web site, where you can download:• The technical data sheet,• The mechanical interface drawing,• The 3D e-drawings file.
The mechanisms shown in this section may all be tuned to your specific requirements: dedicatedinterface, stroke, aperture, operating frequency, etc. Please contact us to discuss about yourrequirements.

The technical information on this chapter is not contractualand can be changed without prior notice.

77

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5.2. X PIEZOELECTRIC
STAGES5.3. XY PIEZOELECTRIC
STAGES5.4. XYZ PIEZOELECTRIC
STAGES

Fig. 5.a: View of the X60S stage

Fig. 5.b: View of the XY25XS stage

Fig. 5.c: View of the XYZ200M stage

CEDRAT TECHNOLOGIES (CTEC)
single axis piezoelectric stages takeadvantage from the characteristics
of APA ® actuators and flexure
guiding, in order to offer excellent
compactness, robustness, bandwidthand resolution. They can be equippedwith strain gauges for very finepositioning or closed loop control.
Parasitic translations and rotations
are very limited.

As other CTEC piezoelectric stages,
the two axis stages inherit the uniquecharacteristics of APA® actuators. The
stage can be equipped with Strain
Gauges (SG) for very fine positioning
or closed loop control. Crosstalk andparasitic rotations are very limited.

Two axis stages can receive a third
motion axis for three degrees of
freedom. Performances in robustness,
bandwidth and resolution inherit
the unique characteristics of APA®
actuators. The stage can be equippedwith Strain Gauges (SG) for very finepositioning. Crosstalk and parasitic
rotations are very limited.

Applications include mask, lens or
detector positioning, micro scanning,
pixel shifting, dithering and line ofsight stabilisation.

The moving frame can be custom
designed (attachment points, holes...)and 2 stages can be stacked for XY
motion.

PARAMETER

Active axis
Displacement(unloaded)
Stiffness
Unloaded resonancefrequency
Resolution
Voltage range
Capacitance (perelectrical port)
Dimensions (X×Y×Z)
Mass
Sensor option

The piezoelectric stage XYZ200M hasa large stroke along the X, Y and Z axis
and is able to bear loads up to 3 kg.

The moving frame can be custom
designed (attachment points,
holes...). This mechanism requires thepush-pull option on the two channelsof the driver. The CCBu20 controller
box is often used for most of theseapplications.

Applications include confocal
microscopy, mask positioning andinspection.
The moving frame can be custom
designed (attachment points,
holes...). The mechanism requires
the push-pull option on the first twochannels of the driver.

UNIT

X60S

X120S

XY25XS

XY200M

XY400M

XYZ200M-

Preliminary
TX

Preliminary
TX

Standard
TX, TY

Standard
TX, TY

Preliminary
TX, TY

Standard
TX, TY, TZ

µm

55

110

25

200

400

200

N/µm

1.2

0.26

2.5

0.59

0.14

0.59

Hz

1 840

850

3 000

580

260

380

nm
V

6
-20 … 150

11
-20 … 150

3
-20 … 150

20
-20 … 150

40
-20 ... 150

20-20 ... 150

µF

1.6

1.6

0.50

6.3

6.3

6.3

mm
g
-

30×30×1223SG

30×30×12
23
SG

50×50×19
80
SG

100×100×22 100×100×27 100×100×49
450
500
540
SG
SG
SG

Table 5.a Characteristics of piezoelectric stages

79

Products Catalogue Version 5.1 - Piezo mechanisms

5.5. TILT TRANSLATOR TT

5.6. DOUBLE TILT TRANSLATOR DTT

Fig. 5.d: View of the Tilt Translator TT60SM

Fig. 5.e: View of the Double Tilt Translator DTT35XSThe Tilt Translator TT is a tilt stage based on 2 APA®
actuators. Two types of motion can be generated:

The Double Tilt Translator DTT is based on 2 pairs of APA®
actuators. Two types of motion can be generated:• A tilt RX motion when one actuator is pushing while theother is pulling.

• A Tilt RX and/or RY motion, when one actuator ispushing while the other is pulling along one axis.

• An optional piston Z motion (piston / translation)
could be made when the two actuators are driven
independently, enabling to control the position of thecentre of rotation. Nevertheless this will require toadjust electrical interface and the control strategy of
the TT60SM. This option is not available in standard
configuration and shall be developed under customer
specifications.

• An optional vertical Z motion (piston / translation) could
be made when the two pairs of actuators are driven
independently, enabling to control the position of thecentre of rotation. Nevertheless this will require toadjust electrical interface and the control strategy of
the DTT35XS. This option is not available in standard
configuration and shall be developed under customer
specifications.

Applications include 1D laser pointing and micro-scanning.

Applications include 2D laser pointing, stablisation, microscanning, pixel shifting, and dithering.

The TT mechanism can be equipped with Strain Gauges(SG) for closed loop operation. If only the tilt motion isrequired, then only one channel is necessary, with the
push-pull option on the driver.

The DTT mechanism can be equipped with Strain Gauges(SG) to operate in closed loop. The two tilt motions are
driven through two amplifier channels with push-pull
option.
The CCBu20 controller box is then particularly suited. The
mirror support interface can be adjusted to welcome up to
50 mm diameter mirror.

PARAMETER

Active axis
Angular displacement
Unloaded resonance frequency
Angular resolution
Voltage range
Capacitance (per electrical port)
Dimensions (Ø×Z)
Mass
Sensor option

UNIT

TT60SM

DTT35XS

DTT60SM

mrad (+/-)
Hz
µrad
V
µF
mm
g
-

RX
> 22
400
1
-20 … 1503
Ø55×35180
SGRX, RY>52600
0.3-20 … 150
0.5
Ø45×25120
SGRX, RY> 10
1750
1-20 … 1503
Ø65×40310
SG

Table 5.b Characteristics of Tilt Translators

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5.7. FAST PIEZO SHUTTERS FPS200M,
FPS400M & FPS900M

5.8. FAST AMPLIFIED PIEZO SHUTTERFAPS400M

Fig. 5.f: View of the FPS200M (courtesy of EMBL)

Fig. 5.g: View of the FAPS400M-SIW–SG-UHVThe Fast Piezo Shutters (FPS) are mechanisms using two
APA® actuators to open and close a slit, up to 1.1 mm inless than 10 ms. They are particularly suited to applications
requiring low jitter, high repeatability or long life time.

FAPS400M is a fast shutter solution for X-Ray beamlinewith large aperture capability (> 3 mm) and short responsetime (< 8 ms).

Design of FPS series is based on APA200M, APA400M
and APA900M actuators. The moving jaw can be made oftungsten to offer very high X-Ray stopping power.
FPS shutters, initially developed by CEDRAT TECHNOLOGIES(CTEC) on an initiative of Mr Cipriani from EMBL andqualified at ESRF Grenoble (France), are now used bysynchrotron facilities all around the word.
The FPS family is driven and controlled by a dedicatedelectronic rack mounted RK42F3U-LC75B + SP75A-2 (seeTable 8.j, page 109)

PARAMETER

The FAPS400M shutter system is based on two APA400M®
each one actuating a mechanical amplifier or a lever arm.
At the end of each lever arm, a Tungsten (W) optical headis integrated. This head is made of an overlapping teeth
pattern in order to provide with a hard stop of the beamline
when the shutter is closed (Power OFF). When the power is
ON, the shutter opens and offers the full aperture.
The overlap between the teeth can be adjusted with ascrew. The optical heads can be removed for replacementby another optical interface. The FAPS400M can bedelivered with a Strain Gauge (SG) sensor to feedback theopen / close status. Vacuum (VAC) and Ultra High Vacuum(UHV) options are also available on request, the Fig. 5.gshows a FAPS400M-SIW-SG-UHV with tungsten teeth,
SG sensor and UHV options. The shutter is driven by thestandard SP75A-2 amplifier mounted rack that can include
additional options like a strain gauge sensor conditioner
board (SG75-1) and a RS-422 connector for long distancecommunication.

UNIT

FPS200M

FPS400M

FPS900M

FAPS400M

Max. beam diameter
Aperture & closing time
Voltage range
Capacitance (per electricalport)
Dimensions (X×Y×Z)
Mass

mm
ms
V

0.30
2
-20 … 150

0.70
4-20 … 150

1.1
10
-20 … 150

3.0
8-20 … 150

µF

3.2

3.2

3.2

3.2

mm
g

73×54×65
150-

TungstenTungsten

Total teeth depth
Sensors option

mm-

60×44×21
150
Stainless steel /Tungsten
2.4 / 4.8
SG

60×44×23
150

Teeth material

60×44×21
150
Stainless steel /Tungsten
2.4
SG

4.8
SG

3.0
SG (c.1)

Table 5.c Characteristics of piezo shuttersc.1 Included, not optional

Products Catalogue Version 5.1 - Piezo mechanisms

5.9. CUSTOMISED PIEZO MECHANISMS
The range of Commercially Off The Shelves (COTS)
mechanisms shown in the previous paragraphs is indeed
the tip of the iceberg in terms of sales revenue andmanufacturing volume at CTEC. Usually a COTS product ishardly ready for a friendly plug and play inside the customer
system for any application. More and more customer’s
requests are demanding in terms of integration andfunctionality. To answer to that reality CTEC has been
demonstrating its capability to deliver customised & OEM
solutions for more than 20 years.
A customised solution is the possibility for a customer to
optimise the performances, the reliability and the cost ofownership for the requested product or function to be

integrated inside his system or application. This customised
solution is either built from building blocks deriving fromexisting COTS solution or built through engineeringdevelopment including design, prototyping and testing
phases.
The purpose of this paragraph is to show (without being
exhaustive) the diversity of the customised solutions interms of piezo mechanisms developed and manufactured
by CTEC for various industrial field. Some of thesecustomised mechanisms have been delivered together
with their controllers in order to provide the customer witha full plug & play integrated function.
Many P-FSM are also developed. Two brochures present
the CTEC heritage in Fast Steering Mirrors and in XY stages.

Fig. 5.i: Piezo XY stage (+/- 10 um stroke) andits controller box for Image stabilisation
Fig. 5.j: Active slits (> 700 µm aperture)
for X ray beam shaper designed withSOLEIL for the SWING beamline

Fig. 5.k: Piezo FSM (+/- 1 mrad stroke) and its
controller box for fine laser pointing & stabilisation
Fig. 5.l: Microscanning piezo XY stage(+/- 10 um stroke) and its driver box forimage resolution enhancement

Fig. 5.h: Piezo Fast Steering Mirror P-FSM150S
for Space optical communication terminal

Fig. 5.m: Piezo activated arms (3 mm stroke)for X-ray filter holder 10 ms switching time81

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please visit these pages:
cedrat-tec.com/products/piezo-motors
cedrat-tec.com/technologies/actuators/piezo-motors-and-electronics

83

Products Catalogue Version 5.1 - Piezo motors and motorised stages

6. PIEZO MOTORS AND
MOTORISED STAGESCEDRAT TECHNOLOGIES (CTEC) offers piezoelectric motors using the patented SPA technology.
The SPA technology allows unique performances through the combination of the Amplified
Piezoelectric Actuators (APA®) technology with the inertial motors principle.
They operate by accumulation of small steps (see §2.1.6. Stepping Piezo Actuators SPA, page19). Between each step, the motor is locked into position and does not need to be powered.
Beside the long stroke mode, they can also be operated in a deformation mode for a fineadjustment. In this case, the stroke is proportional to the applied voltage, thus allowing
nanometer resolution and high bandwidth.
In practice, this allows to build a brand of piezoelectric motors offering:Translation

LSPA

LSPS





Rotation

RSPAIntegrated guiding





MSPA

FSPA







0.1 10 mm

Typical Stroke2 - 10 mm

2 - 10 mm

Infinite

InfiniteHigh speed









Micro-positioning











Nano-positioning

Fine mode

Fine mode

Fine mode

Fine modeUnpowered blocking force











Table 6.a Piezoelectric motors
Note: fine mode implies continuous driving voltage and is not available when motor is powered off.

Several custom designs are presented at the end of this section. They allow multiple combinationsof the various advantages of the SPA technology.

The technical information in this chapter is not contractualand can be changed without prior notice.

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6.1. LINEAR STEPPING PIEZO ACTUATOR LSPA
Linear Stepping Piezoelectric Actuators (LSPA) are linear piezoelectricmotors for micro/ nano positioning applications benefiting from the
APA® heritage.
They contain all the needed elements for an SPA in a minimalist
but efficient manner. This allows easier integration in customer
mechanisms while achieving best performances.
This LSPA can be supplied with CEDRAT TECHNOLOGIES’s (CTEC)
standard compact driver SPC45 or with standard Linear Amplifier
LA75.
Other custom Linear Stepping Piezo Actuators can be designed
based on various APA®.

Fig. 6.a: LSPA35XSPARAMETERUNIT

LSPA30UXSLSPA35XSLSPA40SM-

Preliminary

Preliminary

mm
mm/s
mm/s
µm

6
20
70
5 … 2010
1030
5 … 30

20
5
15
5 …20

µm
nm
N/µm

36.0

44.0

0.09

54.0
<1
0.50

3.84

N
N
N

0.8
0.2
0.3

3
1
2

15
5
10

> Stepping mode

Travel range
Nominal Speed (b.1) (b.2)
Max speed (b.3)
Typical step size (b.1) (b.2)> Fine positioning mode

Stroke (b.1) (b.3)
Resolution (b.3)
Stiffness> Forces

Holding force without consumption
Nominal driving force (b.1) (b.2)
Max driving force (b.3)> DriverNominal driver

SPC45

LA75B

> Mechanical properties

Lifetime (b.4)
HeigthWidth
Length (in actuation direction)Masscycles
mm
mm
mm
g

5.6
11.5
20.1
1.9

Table 6.b Characteristics of LSPA

b.1 Unloaded
b.2 With nominal driverb.3 Custom version and driverb.4 Unloaded, 2mm stroke, nominal speed, 50% duty-cycle> 1 000 000
12.0
16.0
30.0
5.0

14.0
32.0
45.0
18.0

85

Products Catalogue Version 5.1 - Piezo motors and motorised stages

6.2. LINEAR STEPPING PIEZO STAGE LSPS
The Linear Stepping Piezo Stages LSPS are based on the Linear
Stepping Piezo Actuator’s (SPA) principle (see 2.1.6, page 19).
They combine a LSPA with a position sensor and a mechanicalguiding.
LSPS provide:• A long stroke, high speed & blocking at rest
• A position information• A micro/nano positioning resolution
Fig. 6.b: LSPS35XS• A guided motion & robustness• Compactness & easy interfaces
LSPS stages can be driven with SPC45 driver or a linear amplifier
from the LA75 family. Open and closed loop control is available.
Custom stages can be designed with smaller or bigger APA®.

PARAMETERUNIT

LSPS35XSLSPS40SM

Preliminary

Preliminary

mm
mm/s
mm/s
µm

10
10
20

20
5
10

µm
nm
N/µm

54.0
0.50

3.84

N
N
N

3
0.8
2

15
5
10

SPC45

LA75B

> Stepping mode

Travel range
Nominal Speed (c.1) (c.2)
Max speed (c.3)
Typical step size (c.1) (c.2)

5 … 30> Fine positioning mode

Stroke (c.1) (c.3)
Resolution (c.3)
Stiffness

44.0<1> Forces

Holding force without consumption
Nominal driving force (c.1) (c.2)
Max driving force (c.3)> DriverNominal driver> Mechanical properties

Lifetime (c.4)
HeigthWidth
Length (in actuation direction)Masscyclesmmmmmm
g> 1 000 000
15.0
30.0
30.0
30.0

Table 6.c Characteristics of LSPS

c.1
c.2
c.3
c.4

UnloadedWith nominal driver
Custom version and driver
Unloaded, 2mm stroke, nominal speed, 50% duty-cycle

20.0
50.0
50.0
90.0

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6.3. MODULAR STEPPING PIEZO ACTUATOR MSPA
Modular Stepping Piezoelectric Actuators (MSPA) are
piezoelectric motors modules that canbe easily integrated into already guided
mechanisms to drive their mobile part(see application in chapter 6.6, page89).
The MSPA is fixed on one part of themechanism while a friction layer is fixed
on the other part. They can accommodate
limited guiding quality. This greatly eases
their integration in very long stroke
applications (>10 cm) and even allows
their use for non-linear motion (i.e. friction
track is not straight).

The MSPA can be supplied with CTEC’s standard compact
driver SPC45 or with standard Linear
Amplifier LA75. Other Modular Stepping
Piezoelectric Actuators can be designed
using various APA®.
This motor technology provides:• Extreme compactness• High speed & blocking at rest
• Nano resolution• Linear and non-linear motion (rotating
or even curved motion)

Fig. 6.c: MSPA35XS• More than 10 km displacement

As with LSPA, they can also be operated in a deformation
mode for a fine adjustment. In this case, the strokeis proportional to the applied voltage, thus allowing
nanometre resolution and high bandwidth.
PARAMETERUNIT

MSPA30UXS

MSPA35XSMSPA40SM

Preliminary

Preliminary

Preliminary

30
50

∞
10
20

> Stepping mode

Travel range (d.1)
Nominal Speed (d.2) (d.3)
Max speed (d.4)
Typical step size (d.2) (d.3)

mm
mm/s
mm/s
µm

5 … 20

7
10
5 … 25> Fine positioning mode

Stroke (d.2) (d.4)
Resolution (d.4)
Stiffness

µm
nm
N/µm

36.0

45.0

0.09

54.0
<1
0.50

N
N
N

0.8
0.2
0.3

3
0.5
1

10
1.75
2.5

3.80

> Forces

Holding force without consumption
Nominal driving force (d.2) (d.3)
Max driving force (d.4)> DriverNominal driver

SPC45

LA75B+UC45> Mechanical properties

Lifetime (d.5)
Heigth of module
Width of module
Length (in actuation direction)
Mass
Max friction trip run-out

m
mm
mm
mm
g
µm

7.0
15.0
20.0
12.0
±50

Table 6.d Characteristics of MSPA
d.1 Limited by moving partd.2 Unloaded
d.3 With nominal driver
d.4 Custom version and driver
d.5 Unloaded, nominal speed, 50% duty-cycle, ambient conditions> 2 000
10
20
30.0
20.0
±100

20.0
20.0
50.0
40.0

87

Products Catalogue Version 5.1 - Piezo motors and motorised stages

6.4. ROTARY STEPPING PIEZO ACTUATORS RSPA
Rotary Stepping Piezoelectric Actuators (RSPA) are rotary
piezoelectric motors with 360° revolutions. They operate byaccumulation of small steps (see §2.1.6. Stepping Piezo Actuators
SPA, page 19).
This motor technology provides:• Extreme compactness• High rotational speed & blocking at rest
• Nano resolution
Fig. 6.d: RSPA30uXS with customised output axis

• More than 1 million cycles
The motor is locked in position when unpowered. RSPA can besupplied with CEDRAT TECHNOLOGIES’s (CTEC) standard compact
drivers SPC45 or with standard Linear Amplifier LA75. Custom
Stepping Piezo Actuators can be designed based on various APA®.

PARAMETERUNIT

RSPA30UXS

RSPA35XS

Preliminary

Preliminary> Stepping mode

Travel range
Nominal Speed (e.1) (e.2)
Max speed (e.3)
Typical step size (e.1) (e.2)

rad
rpm
rpm
mrad

∞
20
50
0.2 … 2.5

1022
0.2 … 3> Fine positioning mode

Stroke (e.1) (e.3)
Resolution (e.3)

mrad
µrad

4

mNm
mNm
mNm

2.8
0.7
1

3.9
< 0.1

> Torques

Holding torque without consumption
Nominal driving torque (e.1) (e.2)
Max driving torque (e.3)

10
2.5
3.5

> DriverNominal driver

SPC45> Mechanical properties

Lifetime (e.4)
HeigthDiameterMasscyclesmmmm
g> 1 000 000
10.0
12.0
3.0

Table 6.e Characteristics of RSPA

e.1 Unloaded
e.2 With nominal driver
e.3 Custom version and drivere.4 Unloaded, 2mm stroke, nominal speed, 50% duty-cycle

18.0
20.0
8.0

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6.5. FINE STEPPING PIEZO ACTUATOR FSPA
Fine Stepping Piezo Actuator (FSPA) is a patented actuator thatcombines SPA technology with mechanical reduction. This allows
to achieve very small step sizes even down to 10 nm. Typical max
speed for FSPA is 200 µm/s.
Another major advantage of FSPA is its ability to maintain its position,
while unpowered, even when very large outer forces or acceleration
are applied.
The main application for this actuator is to finely tune the position of a
payload and hold this position afterward even though environmental
conditions may get real bad such as vibration and shocks during offroad transportation, space launch or aircraft landing…

Fig. 6.e: FSPA35XSPARAMETER

UNIT

StatusFSPA35XS

Preliminary> Forces

Actuation force (f.1)
Holding force (f.2)

NN

20 /100
> 200

mm
nm
µm/s

5
< 100
200

> Stepping mode

Travel range
Typical min step size (f.3)
Typical max speed (f.4)> DriverNominal driver

SPC45> Mechanical properties

Typical lifetime(f.5)
Dimensions
Total mass

Cyclesmmg100
Diam 40 x 62
160

Table 6.f Characteristics of FSPA

f.1 Max actuation stall force, no more displacement, depending on the max ouptut peak current of the driver (20N @ 150 mA peak with SPC45 / 100N @ 1.2 A with Highpower amplifier)f.2 Unpowered
f.3 Minimum Step size in coarse positioning mode for 50V output voltage step with SPC45
f.4 Maximum speed in coarse positioning mode for 100V output voltage step with SPC45
f.5 1 cycle is over 2 mm stroke at max speed , for higher number than 100 cycles please contact CTEC

Products Catalogue Version 5.1 - Piezo motors and motorised stages

6.6. CUSTOMISED PIEZO MOTOR MECHANISMS
6.6.1. ROTARY STAGE

6.6.4. 3 AXIS CLOSED LOOP MECHANISM

The rotary stage is a demonstrator of an MSPA integration(see Fig. 6.f). An MSPA35XS is simply pressed against acommon ball bearing. This basic Ø80 mm mechanism
achieves 2 tr/min and a 0.2 mrad a resolution.

Thanks to their flexibility, MSPA can be combined toachieve direct multi-degrees of freedom movement. In thefollowing mechanism (see Fig. 6.j), 3 MSPA are joined toachieve simultaneous Rx, Ry, Tz movement.

6.6.2. LONG STROKE LINEAR STAGE
This linear stage is a demonstrator of an MSPA combinedwith a basic linear ball bearing guiding. The MSPA has been
attached to the moving stage and is then able to travel
on more than 100 mm with 20 mm/s. A 5 µm stepping
resolution can be achieved.
The customised MSPS35XS stage shown in (see Fig. 6.g)
is based on fixed MSPA35XS driving a linear guided top
plate in motion. The MSPS35XS stage aims at adjusting
the focus of a lens payload fixed on the top plate over 17
mm linear stroke in a compact size (~76×56×23 mm) andlow mass (~130 grams). The max speed is 8 mm/s andthe driving force is greater than 1 N with standard SPC45
controller.

6.6.3. LONG STROKE CURVED STAGE
In this application, the capability of the MSPA achieve
curved motion is demonstrated (Fig. 6.i). The MSPA is
driving a flat turning track on 90°. Thanks to the robustnessof the MSPA technology, the radial speed variation has no
significant impact on the driving characteristics.

In that sense the mechanism is similar to a standard
DTT35XS. However, using the MSPA35XS stroke
capability, the achievable stroke is a hundred times larger(Rx=Ry=+/-2.5°, Tz=+/-2 mm). Simultaneously, extreme
pointing resolution remains available using the finemovement mode.
Additionally, the mechanism includes position sensors tomonitor the 3 axis instantaneous position. Closed loop
control has then been demonstrated both for speed or
position control.

6.6.5. SPACE FSPA
Derived from the FSPA motor, a customised spacecompliant actuator is designed and tested for the IASI-NG
space project (Fig. 6.k). This actuator includes complete
cold redundancy. All major components are doubled,
including the FSPA derived actuators.
The motor provides 150 µm stroke and is targeting a better
than 50 nm position stability when unpowered.
Fast positioning and nanometric position sensing are also
included though the addition of 2 PPA actuators as well as
2 ECS sensors.
Due to the space dedication of this actuator, all design andtesting activities comply with the ECS standard.

Fig. 6.f: MSPA rotary demonstrator

Fig. 6.g: MSPA long stroke demonstrator

Fig. 6.h: MSPS35XS linear stage

Fig. 6.i: MSPA curved track demonstrator

Fig. 6.j: 3 axis closed loop mechanism

Fig. 6.k: FSPA EM for IASI-NG

89

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For more information on this chapter,
please visit these pages:
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Products Catalogue Version 5.1 - Magnetic Actuators

7. MAGNETIC ACTUATORSCEDRAT TECHNOLOGIES (CTEC) has a large heritage in magnetic actuators, sensors and driving
electronics. It has been designing, optimising and manufacturing electro-magnetic actuatorssuch as moving iron, voice coil, moving magnet and electromagnet actuators for its customers
for more than 20 years.
The MICA™ and BLMM actuators series are standard products. They are powerful, compact,
dynamic and precise actuators.
Beyond these standard products, CTEC also offers a complete range of engineering services
from specifications to custom products: Feasibility, design, optimisation, prototyping, testing,manufacturing and training.

The technical information on this chapter is not contractualand can be changed without prior notice.

91

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7.1. MOVING IRON CONTROLLABLE ACTUATOR MICA™
Moving Iron Controllable Actuators (MICA™) are patented
magnetic actuators from CEDRAT TECHNOLOGIES (CTEC).
They provide a controllable high force along the stroke.
It is particularly suited for dynamic applications requiring
long strokes. MICA™ actuators provide:• Large force in a compact design.
• High dynamics, meaning highacceleration (see Fig. 7.b).
• High reliability.
• Maintenance free flexure bearing
available• High resolution: MICA™ actuators
have a continuous displacement,
enabling to reach high resolution.
For extreme resolution, frictionlessguiding should be chosen (Fig. 7.a).

capabilities either passively (heater, thermal interface)or actively (fan, forced air).
Other capabilities are available as options:• Frictionless long life flexure bearings: Efficient flexure
bearing design allows to achieve
aerospace and military standardof 20 000 hours at 50 Hz i.e. morethan three billions cycles full strokein continuous operation, friction
free (linear behaviour) and tunable
natural frequency. Flexure bearings
improve the output power capability
at resonance frequency (see §2.2.9.
Resonant flexure bearing actuators,
page 34).
• Incremental position sensor:
eve r y M I C A ™ c a n i n te g r a te
15 µm resolution sensor. Higher
performances (less than 1 µm) canbe achieved upon request.

Fig. 7.a: MICA300CM-FB with
flexure bearing option• Low self-heating: MICA™
actuators’ configuration natively
helps in thermal dissipating and of course integrates
a temperature sensor to monitor the coil heating.
Performances can still be increased thanks to cooling• Cooling interfaces: the unique design of MICA™ allows
to easily plug efficient cooling systems when operatingand environmental conditions lead to thermal issue
management.

30

0C

M

Central force (N)

50

0L

Pre
lim
ina
No ry
mi
na
l Fo
rce
Pe
ak
Fo
rce

500
Cubic
Cylindrical

20

0M

400

10

0M

300

CS

20

0C

M

200

20

CS

50

100

2

4

6

8

Fig. 7.b: MICA™ series overview Force / Stroke

10

12

Max stroke
(mm)

93

Products Catalogue Version 5.1 - Magnetic Actuators• Accessories: MICA™ design is also compatible withstandard mechanical accessories: brackets, ball joint,
supports…

Actuators are also named with respect to their size: S for
small, M for medium and L for large.
Nominal performances are given force continuous
operation without any cooling feature.

The MICA™ actuators may have a stroke larger than
10 mm, and forces range from 20 N to 550 N.

MICA™ remains also
compatible with off the shelf
power amplifier existing on
the market.

MICATM High Stroke
Lower Force

Peak performances are achieved for a duration of
10 seconds at 25°C (reaching max 155°C in the coilwinding).
Available stroke is definedas the possible mechanicaltravel between end-stops.

Force

They are versatile actuators: precise at low speed, efficientat resonance and providing high force above resonancefrequency. All those magnetic
actuators can be driven
with our drive electronics(see for example our
CSA96 switching amplifier).

With dedicated cooling,
the peak force becomesachievable in continuous
operation.

MICATM High Force
Lower Stroke

StrokeMICA™ can be customised
and tuned to achieve higher
To model the behaviour
Tuning Force / Stroke for MICA™
stroke with compromiseof magnetic actuators,
on the force. For example
CTEC provides COMMACT™
MICA300CM can extend its
software. It is a dedicatedFig. 7.c: Tuning Force / Stroke for MICA™ C
stroke from 12 to 20mm
tool that draws MICA™
when reducing nominal force
per formances
(see
from
300
to
150
N
(see
Fig.
7.c).
paragraph §2.2. Tutorial on magnetic actuators, page27). This tool allows direct exploitable results for theuser. It is available upon request.

See characteristics of cubic and cylindrical shapes MICA™
next page, in Table 7.a and Table 7.bSince every application is specific, CTEC has created two
types of shape factor for these MICA™ actuators: Cubic or
Cylindrical shape.

Fig. 7.d: MICA500L

Fig. 7.e: MICA200M

Fig. 7.f: MICA20CS

Fig. 7.g: MICA300CM (no option)

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PARAMETERUNIT

MICA100M

MICA200M

MICA500L-

PreliminaryStandard

Standard

N
N/A
N
N/A
mm
N
N
Ohm
mH
g
kg
kg
mm
mm

100
7
200
6
3
90
75
0.2
4
170
Flexure
2.0
0.12
80×80
115

175
12
320
9
5
160
130
0.2
6
160
Flexure3.2
0.21
120×80
115

330
22
440
17
10
230
185
0.6
90
50
Flexure8.0
0.85
150×140
160

-







-







> Specifications

Nominal Force
Nominal Force constant
Peak Force
Peak Force constant
Stroke (peak to peak)Nominal Force @ 50% stroke
Nominal Force @ 80% stroke
DC ResistanceInductance
Max Acceleration
Standard linear bearing type
WeightMoving mass
Cross section size
Length> OptionsSensorFlexure bearing(a.1)

Cooling- (a.1)

Table 7.a Characteristics of cubic shape MICATM actuators
PARAMETERSUNIT

MICA20CS

MICA50CS

MICA200CM

MICA300CM-

Standard

Preliminary

PreliminaryStandard

Nominal Force
Nominal Force constant
Peak Force
Peak Force constant
Stroke (peak to peak)Nominal Force @ 50% stroke
Nominal Force @ 80% stroke
DC ResistanceInductance
Max Acceleration
Standard linear bearing type
WeightMoving mass

N
N/A
N
N/A
mm
N
N
Ohm
mH
g
kg
kg

20
40
30
30
1
14
7
13.5
80
50
Flexure
0.35
0.14

50
10
80
9
4
35
18
0.3
3
55
Bushing
1.2
0.15

200
24
360
20
10
150
70
0.3
8
120
Bushing
1.9
0.30

300
33
540
30
12
230
110
0.3
12
95
Bushing
3.2
0.58

Diameter

mm

40

70

90

100

Length

mm

60

70

90

120

Sensor- (b.1)Flexure bearing

-

(b.2)







Cooling

-







> Specifications> Options

Table 7.b Characteristics of cylindrical shape MICATM actuators
a.1 Standard configuration, not optional
b.1 Force sensor
b.2 Standard configuration, not optional

95

Products Catalogue Version 5.1 - Magnetic Actuators

7.2. BISTABLE LINEAR MOVING MAGNET BLMM
BLMM stands for Bistable Linear Moving Magnet. Those magnetic
actuators are based on a permanent magnet moving between two
opposite electromagnets.
The main advantage of the BLMM is its holding force without dissipation
when not powered. This makes BLMM perfect for applications such aslatches devices, locking devices, electro valves, contactors, etc...
BLMM Advantages:• Holding force at rest
Fig. 7.i: BLMM1XS, production batch• Fast commutation• Small size
• Simple current pulse

Fig. 7.h: BLMM200M with customised interface

PARAMETER

StrokeHolding force at rest (Fh)Commutation time
Nominal commutation current I
Total Mass
Actuator diameter size
Height actuator (without shaft)
Type of shaft
Diameter Mobile shaft

UNIT

BLMM1XS

BLMM50S

BLMM200M

mm
N
ms
A
g
mm
mm
mm

Standard
> 0.5
0.08
< 1.7
+/- 1.2
1.1<6
6.8

Preliminary
3
50
< 10
+/- 6
50
25
20
All through shaft
3Standard
7
200<90+/- 15
1 200
80
91

0.8

Table 7.c Characteristics of BLMM

8

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7.3. TUNABLE PROOF MASS ACTUATORS
Proof Mass Actuators are inertial vibration generators,
mostly intended for vibration cancellation, vibration
damping or shaking applications. The operating principleof such actuators is based on the use of a resonant Flexure
Bearing Actuators, attached to a counter mass, that can betuned according to specific resonance frequency
requirements. In order to do so, both counter mass, andflexure bearing assemblies, can be optimised on demandfor each custom application.

Cedrat Technologies proposes customable Proof Mass
Actuators, based on the standard MICA300CM andMICA20CS Flexure Bearing Actuators, with tunable counter
mass, respectively optimised for operation with CSA96
and CSAu10 drive electronics. These devices findapplications in machine tools and in instruments.

Fig. 7.l: MICA20CS Proof Mass actuator

Fig. 7.j: MICA300CM Proof Mass actuator

Fig. 7.m: MICA20CS Proof Mass actuator inertial
force and heat dissipation analysis

Fig. 7.k: MICA300CM Proof Mass actuator inertial
force and heat dissipation analysis

PARAMETER

Tunable moving mass
Tunable resonance frequency (d.1)
Maximum inertial force range (d.2)

UNIT

MICA20CS PROOF MASSMICA300CM PROOF MASS

kg
Hz
N

0.14 - 0.60
12 - 25
20 - 25

0.60 - 1.50
18 - 30
250 - 350

Table 7.d Characteristics of MICA™ Proof Mass
d.1 Achieved by tuning only the moving mass. Other resonance frequencies can be achieved with custom flexure bearing configurations.
d.2 In the vicinity of resonance frequency and above

97

Products Catalogue Version 5.1 - Magnetic Actuators

7.4. SPECIFIC MAGNETIC ACTUATORS
Beyond standard linear magnetic actuators shown in the previous
sections, CEDRAT TECHNOLOGIES (CTEC) develops customised solutions
to address customer specific requirements in terms of performances andenvironment. These customised solutions are either built by modificationof existing COTS solution or built through engineering development
including design, prototyping and testing phases. The purpose of thissection is to give some examples of specific realisations.
Fig. 7.n: MCA stator

7.4.1. MOVING COIL ACTUATORS MCASpecific linear voice coil actuators have been developped and spacequalified for MTG (Meteosat Third Generation) (see Fig. 7.n and Fig. 7.k).
• Force homogeneity < 2 % all along the stroke• Redundant architecture• Space qualified MCA (Cleanliness, Vibration, Thermal)• Stroke = 24 mm• Force constant = 12 N/A

Fig. 7.o: MCA moving part7.4.2. EXTRA FLAT MICA™ STAGESMICA™ technology allows for making X stage (see Fig. 7.l) as well as XY
stage (see Fig. 7.m).
The flat MICA™ X stage offers the following features :• Integrated proof mass
• Tangential motion (along long dimension)• Highly dynamic• Peak force = 600 N

Fig. 7.p: Flat MICA™ X stage• Force constant = 30 N/A• Stroke = 6 mm
The XY stage offers a 2D continuous motion in X and Y directions,perpendicularly to the Z axis. A central hole can welcome an optic. Typicalapplication is active stabilisation and antiblur. Key performances are :• Peak force = 2 N• Stroke = 2 mm

Fig. 7.q: XY MICA™ stageCEDRATTECHNOLOGIES
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7.4.3. SPECIFIC ELECTRO-MAGNET ACTUATOR EMAElectro-Magnet Actuators (EMA) are suitable when design-to-cost isrequired. Such an actuator type is deemed relevant when medium tolarge production is considered. In addition they provide high force in acompact volume. CEDRAT TECHNOLOGIES has the necessary knowledge,
equipment and experience to provide custom design as well as production
batches.
Fig. 7.r shows an example of production batch based on CTEC custom
design for the automotive sector. These specific EMA offer the following
performances:Fig. 7.r: Electromagnets production batch• Force = 30 N
• Stroke = 2 mm
• Response time < 10 ms

7.4.4. SPECIFIC MOVING IRON ACTUATOR
Specific moving iron actuator are necessary for controllable dynamic
operations. The special design showed on Fig. 7.s illustrates a moving
iron actuator equipped with flexure bearings for long life time purposes.
Elsewhere, this actuator works by pair, in a push pull mode, in orderto provide high force level at resonance frequency. The customisation
includes an embedded drive electronic, one displacement sensor and aclosed loop control.
This specific moving iron actuator offers the following performances:• Force = 80 N
• Stroke = 8 mm
Fig. 7.s: Specific moving iron actuator• Bandwidth >100 Hz

Products Catalogue Version 5.1 - Magnetic Actuators

7.4.5. ASYNCHRONOUS LINEAR MOTOR
Whereas previous specific actuators are limited in stroke, in somecases, custom actuators requires unlimited displacement range toconvey one payload in a defined pattern. The conventional solution
involves one rotating motor and a transmission belt. The main drawbackof this solution remains on the maintenance cost. That is the reason
why CTEC proposes a custom belt free conveyor in a contactless linear
motor. The custom design showed on Fig. 7.t allows multiple carriage
synchronization by speed control
Main performances of this dedicated asynchronous motor are thefollowing:

Fig. 7.t: Specific asynchronous linear motor• Force = 20 N
• Stroke = only limited by the number of components.
• Controlled Speed = 0.4 m/s

7.4.6. MAGNETIC FAST STEERING MIRROR M-FSM
To offer an alternative to piezoelectric DTT for Fast Steering Mirrors (FSM),CTEC develops also Magnetic-actuators-based FSM (M-FSM). M-FSM
realises optical pointing with larger motion than piezo DTT while keeping
high resolution and large bandwidth. Typical applications are Free Space
Optic (FSO) communication links, laser guide star, laser designators…
For example, a recent development has led to a M-FSM (Fig. 7.u)
producing large bandwidth Angular Strokes Rx Ry > +/- 2°. The M-FSM
mechanism volume contains the mirror, the actuators, the guiding andthe ECS position sensors. High performance MICA™ allows to perform the
dynamic strokes with low heating. Frictionless flexure bearings allow toachieve both high resolution and infinite life time. Associated electronics
for sensing, driving and controlling are the ECS45 and MCSA480. Theseelectronic offer both open & closed loop control modes with high dynamic
performances thanks to 10 A / 48 V high current / voltage limits andadvanced controlled laws.

Fig. 7.u: Magnetic Fast Steering Mirror
M-FSM62 (with D31 mm mirror)

Key performances are :• Angular strokes Rx Ry = 70 mrad
• Full stroke bandwidth > 200 Hz• Mechanism Volume = Ø 62 mm × H56 mm
Other M-FSM are developed. Please consult dedicated brochure and web
page

Fig. 7.v: Magnetic Fast Steering Mirror
M-FSM45 (with D17 mm mirror)

99

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For more information on this chapter,
please visit these pages:
cedrat-tec.com/products/piezo-controllers
cedrat-tec.com/products/magnetic-controllers
cedrat-tec.com/products/piezo-motor-controller

Products Catalogue Version 5.1 - Drive Electronics & Controllers

8. DRIVE ELECTRONICS& CONTROLLERSCEDRAT TECHNOLOGIES (CTEC) offers a range of electronic amplifiers and controllers to drive
both in open and closed loop in an optimal manner its own range of piezo actuators, magnetic
actuators and piezo motors. These amplifiers & controllers are available either integrated in
powered 19” sub-rack (mainly for laboratory & factory use) or integrated in DC powered OEM
board & box (mainly for embedded applications).
The range of powered sub-rack mounted & OEM series are further described in the following
paragraphs.

The technical information on this chapter is not contractualand can be changed without prior notice.

101compact dynamic precise

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8.1. AMPLIFIERS & CONTROLLERS FOR PIEZOACTUATORS
8.1.1. OEM SERIESThe Compact Amplifier CAu10 (Fig. 8.a) and Compact Controller Board
CCBu20 (Fig. 8.b) are OEM amplifiers and controllers available off the
shelves.
Fig. 8.a: CAu10

PARAMETER

The CAu10 is a miniature two-channels ampliﬁer board with both analog
and digital (SPI communication) inputs. It is used for driving piezo
actuators in open loop, which is able to deliver 5 mA per channel andrequires a DC voltage supply of 5 to 12 V.
UNIT

CAU10 (A.1)> General

Function
Number of channels

Embedded Driver for piezoelectric actuators
2 + Push Pull

> Input

Analogue Control Input voltage
Digital Input voltage (SPI protocol)VV

0 … +3.3
3,3VmA+5 … +150
±5

VA

1

V/V

45

kHz

2

dB

70

VDC

5 … 12> Output

Typical output voltage
Continuous output current (a.2)> Power amplifier

Peak output power (a.3)> GainGain> Dynamic performance

Small signal bandwidth (-3dB) (a.4)> Noise performance

Signal to Noise Ratio (a.5)> Power Supply

Main Power supply> Options

Connector interface option for CAu10 2 channels

To connect two actuators

Table 8.a Characteristics of CAu10

a.1 Guaranted in labs environment
a.2 Internally limited
a.3 AC+DC apparent power, sine signal
a.4 Unloaded
a.5 Computed as RMS output signal/RMS output Noise floor

103

Products Catalogue Version 5.1 - Drive Electronics & Controllers

The CCBu20 and CCBU40 are 2-channel push-pull controller boxes,
designed for driving the XY stages & Fast Steering Mirrors piezomechanisms developed by CEDRAT TECHNOLOGIES (CTEC).
They can be operated in open loop or closed loop configurations, withup to 2 axes.

Fig. 8.b: CCBu20 and CCBu40

PARAMETERUNIT

CCBU20CCBU40> General

Function
Number of control channels
Digital communication
Graphical User Interface

All-in-one piezo-driver and controller
2
RS422
CTEC HDPM> Digital control

Control strategy
Sampling rate
Digital resolution

Tunable PID + Stabilizing filters
kSps
bits

20

50
16

> Analog inputs

Number of analog inputs
Analog inputs Voltage range

2-10 ... +10

V> Strain gages (SG) conditioner

Number of channels
Output voltage range

V2-10 ... +10> Piezo driver

Number of channels
Nominal output voltage range
Peak output current
RMS output current (b.1)

V
A
Arms

2
-20 ... +150
0,2
0,035

0.5
0.35

> Power supply

Recommended supply voltage

Vdc

+28

> Miscellaneous

Mass
Dimensions
Operating temperature range (b.2)

kg
mm3
°C

0.25
91 × 77 × 35.2

0.8
160 x 170 x 36
-40 … +70

> External sensor option (b.3)

Functionality
Input voltage range

V

Connection of an external analog sensor on the CCBu20-10 ... +10

Table 8.b Characteristics of CCBu20 & CCBu40
b.1 At +28 Vdc supply and @70°C. Lower output current has to be considered for lower supply voltages
b.2 Additional heatsink might be required
b.3 Applies to both channels; replaces the integrated SG conditioner

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8.1.2. POWERED RACK MOUNTED SERIESThe powered mounted series consists of a number of
powered 19” sub-rack reference. A powered rack or caseincludes as standard an AC/DC (either linear or switching)converter board to convert the power from the mainelectrical power and to deliver it to the other functionalboards (amplifier, conditioner & controller) presented in
the next paragraphs. The powered 19’’ sub-rack can beinserted in an industrial cabinet.

PARAMETER

RK42F3U-LC75BThe powered bench top (Fig. 8.c next page) and thepowered 19’’ sub-rack (Fig. 8.d next page) allow forvarious combinations of amplifier, sensor conditioner andcontroller boards with single or multi channels as well as
output power options.
The Table 8.c shows the different possibilities to build yourconfiguration.

RK42F4U-LC75C

RK84F4U-1LC75B

RK84F4U-1LC75C

1 of eachLinear6 in total 6 in total

RK84F4U-2LC75C

RK84F4U-3LC75C

RK84F4U-1SC75D

RK84F4U-2SC75D

Switching converter
1 of each 2 of each> Application

AC-DC converter topology
Max. No. of hosted amplifiers& conditioner boards
Max supplied current

2 in total

2 of each

3 of each

(c.1)

(c.1)

(c.1)

(c.1)

0.75 A

2.55 A

5.1 A

7.65 A

20 A

2 x 20 A

T., OC.,
HBD.

T., OC.,
HBD.

T., OC.,OV.

T., OC.,
OV. (c.3)



SA75A - Up to 2 channels (c.4)

SA75B - Up to 2 channels (c.4)(c.1)

0.75 A

2.55 A> Power supply

Supply voltage
Supply frequency

110/240 VAC
50-60 Hz

> Protections

Protection type (c.2)

T., OC.,
HBD.

T., OC.,
HBD.

T., OC.,
HBD.

T., OC.,
HBD.

> Board compatibility

LA75A - Up to 3 channels







LA75B - Up to 2 channels







LA75C - 1 channel

SA75D - 1 channel
SG75 - Up to 3 channels
ECS75 - Up to 3 channels







 (c.4)















(c.4)















Table 8.c Characteristics of powered racks

c.1
c.2
c.3
c.4

Sum should not exceed the max supplied current
T: Thermal; OC: Overcurrent; HBD: Hosted board default; OV: Overvoltage
Each SC75 board
Only 1 channel

Products Catalogue Version 5.1 - Drive Electronics & Controllers

The 8 powered rack or case items available off the shelves are listed below:• RK42F3U-LC75B
Powered benchtop case for LA75A or B amplifier board,• RK42F4U-LC75C
Powered benchtop case for LA75C amplifier board,• RK84F4U-1xLC75B
Powered 19’’ sub-rack for multiple LA75A or B amplifier boards,• RK84F4U-1xLC75C
Powered 19’’ sub-rack for LA75C amplifier or multiple LA75A or B amplifierboards,Fig. 8.c: RK42K powered benchtop case

• RK84F4U-2xLC75C
Powered 19’’ sub-rack for 2 LA75C amplifier boards,• RK84F4U-3xLC75C
Powered 19’’ sub-rack for 3 LA75C amplifier boards,• RK84F4U-1xSC75
Powered 19’’ sub-rack for 1 SA75A, B or D switching amplifier board,• RK84F4U-2xSC75
Powered 19’’ sub-rack for 2 SA75A, B or D switching amplifier boards.

For driving and/or controlling piezo actuators according to your application, thepowered rack can welcome:• A linear (LA75) or switching (SA75 or SP75) voltage amplifier (see §8.1.3.
Linear voltage amplifiers, page 106 and §8.1.4. Switching voltage
amplifiers, page 106),• A sensor conditioning board for monitoring option (see §9. Sensors &Conditioners, page 121 for description),• A digital controller board for closed loop control option (see §8.1.6. Digital
controllers, page 110),
The powered 19’’ sub-rack series are more versatile and mainly dedicated forlaboratory and factory use.

Fig. 8.d: RK84F powered 19’’ sub-rack

105

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8.1.3. LINEAR VOLTAGE AMPLIFIERS

8.1.4. SWITCHING VOLTAGE AMPLIFIERS

The linear voltage amplifier are designed to be compatible
with the RK42F and RK84F powered sub-rack series(see chapter 8.1.2, page 104). The LA75 series ofLinear voltage Amplifier board offers the most common
solution to drive piezo actuators. The LA75 is designed
to drive capacitive loads like piezoelectric actuators withextremely low noise. It can perform amplifying operationsin the -20/150 V range. The LA75A-x and LA75B-x canbe equipped with the push pull option. LA75A-x is a lowpower amplifier integrated on a 19” board and can have up
to 3 independent channels. LA75B-x is a medium power
amplifier integrated on a 19” board and can have up to
2 independent channels.

The Switching power Amplifiers SA are designed to becompatible with the Switching Converter SC75 powered
sub-rack series (see chapter 8.1.2, page 104). They allow
to perform either linear continuous state (SA75) or purely
ON/OFF states (SP75) on piezo actuators with extremely
short response times. The switching technique allows highcurrent peaks, required by impulse or by high frequency
applications on large capacitance piezo actuators.

The LA75C has a much higher current capability, suitedfor high frequency and/or short response time/impulse/
fast applications. It shows the highest continuous output
power capability of the linear voltage amplifiers for piezo
actuators available on the market.
See Table 8.d, page 107 for characteristics.

The SA75A, B and D have max continuous output currentsof respectively 5, 10 and 20 Amps.
These amplifier boards can be integrated in either apowered 19” sub-rack RK84F4U-1xSC75 or RK84F4U2xSC75 for respectively 1 or 2 board arrangements
per rack with optional sensor conditioners and digital
controllers.
The switching amplifiers have been developed incollaboration with the G2ELAB of UJF Grenoble (France)in the frame of AVIBUS and PPSMPAB projects. Those
2 projects aimed at driving large piezo actuators for fastmachining or helicopter flap actuation
See Table 8.e, page 108 for charasteristics.

Fig. 8.g: SA75D amplifier board

Fig. 8.e: LA75C, LA75B-2 & LA75A-3 amplifier boards

Fig. 8.h: Comparison of power bandwidth for
SA75A, B, D for continuous peak output current

Fig. 8.f: Comparison of power bandwidth for
LA75A, B, C for continuous peak output current

107

Products Catalogue Version 5.1 - Drive Electronics & Controllers

PARAMETER (D.1)

UNIT

LA75A

LA75B

LA75C

1…3

Driver for piezoelectric actuator
1…2

1> General

Function
Number of channels> Input

Control input voltage

V-1 … +7.5

V
mA
mA

±90
-

-20 … +150
±360-

± 2 400± 6 800

VA

-

-

360

> Output

Output voltage
Continuous peak output current (d.2)
Transient peak output current (d.3)> Power amplifier

Peak output power (d.4)> Gain

Gain

V/V

20

kHz

30

dB

85

> Dynamic performances

Small signal bandwidth (-3 dB) (d.5)> Noise performance

Signal to noise ratio (d.6)> Protections

Protections

Overcurrent, overtemperature, overvoltage> Options

Push pull
UC55
Piezo cable
T LEMOLEMO -BNC adapter

Capability to drive push-pull piezo mechanisms
Controller for position loop - See specific datasheet
Specific length on request - Please contact CTEC for more detailAble to connect 2 CTEC actuators in parallel - Please contact CTEC for more detail
Converts LEMO to BNC connector
Table 8.d Characteristics of LA75A, B & C

d.1 Guaranted in labs environement
d.2 Electronically limited
d.3 With EPC Enhanced Peak Current - During 600µs with a max repetition rate of 20ms - Internally limited - see specific application note
d.4 Max. instantaneous output power = max(p(t)) = max(u(t) x i(t)), with EPC.
d.5 Unloaded
d.6 Computed as RMS output signal / RMS output Noise floor. [1; 200]Hzcompact dynamic precise

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PARAMETER (E.1)

UNIT

SA75A

SA75B

SA75D

> General

Function
Number of channels

Driver for piezoelectric actuator
1> Input

Control input voltage

V-1 … +7.5

VA±5-20 … +150
±10

±20

VA

750

1 500

3 000

> Output

Output voltage (e.2)
Continuous peak output current (e.3)> Power amplifier

Peak output power (e.4)> Gain

Gain

V/V

20

Hz

3800

dB

60

> Dynamic performance

Small signal bandwidth (-3 dB) (e.5)> Accuracy

Signal to noise Ratio (e.7) (e.8)> Protections

Amplifier protections
Actuator protections

Overcurrent, overtemperature, overvoltage
Overcurrent, overtemperature> Options

UC55
Piezo cableMulti outputs LEMO front panel

Controller for position loop - See specific datasheet
Specific length on request
Allows to connect several actuators in parallel - Please contact CTEC for moredetails
Table 8.e Characteristics of SA75A, B & D

e.1 Guaranted in labs environment
e.2 Digitally limited, can be increased to -200 … +200V upon request
e.3 Electronically limited
e.4 AC+DC apparent power. For sine signal with offset, RMS² is (PEAK/√2)² + OFFSET²
e.5 Unloaded. Order = 1Vpp
e.6 With 30µF load at 160Vpp
e.7 With 30µF load. Order = 0V
e.8 Computed as RMS output signal/ RMS output Noise floor. 40 Hz … 20 kHz

Products Catalogue Version 5.1 - Drive Electronics & Controllers

8.1.5. TWO STATES POWER AMPLIFIERThe Two States Power SP75A amplifier board is a designed two states
power driving board.
Only two positions can be obtained:• OFF position at rest (-20 Volt DC),• ON position (150 Volt DC).
The two positions are controlled by a TTL signal. The overshoot of thepiezo actuator can be reduced after calibrations of the slew rate or the
implementation of a signal pre-shaping.
Fig. 8.i: SP75A-2 amplifier board

PARAMETER (F.1)

UNIT

General
Function

SP75A

2 state power driver> Input

Control Input voltage

V

0 … +5
TTL signal / CMOS

V
mA

-20 … +150
±480

> Output

Output voltage
Transient peak output current (f.2)> Dynamic performance

Type of output signal excitation

Preshaping waveform> Noise performance

Signal to Noise Ratio (f.3)

dB

85> Protections

Protections

Overcurrent, Overtemperature, Overvoltage> Options

RS422 communication
SG75
Piezo cable
LEMO -BNC adapter

Capability to communicate the two states order with differential pairs
Monitoring of the position - See specific datasheet
Specific length on request - Please contact CTEC for more detail
Converts LEMO to BNC connector
Table 8.f Characteristics of SP75A

f.1 Guaranted in labs environement
f.2 Electronically limited
f.3 Computed as RMS output signal / RMS output noise floor. [1;200]Hz109

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8.1.6. DIGITAL CONTROLLERS
For closed loop applications (Fig. 2.w), Cedrat Technologies (CTEC) offers
different solutions built around digital controllers in order to adapt to theapplication’s requirements. All controllers come with a USB connection
for interfacing with a computer. The controllers implement PID real-time
control with additional stabilising output filters (low-pass filters, notch
filters). They feature analog inputs for the orders and sensors, andanalog outputs for the commands to the amplifiers. The different control
parameters can be tuned through the USB connection. Dedicated GUI
software is provided to allow easy tuning of the control laws and ordering
displacements. This software is called HDPM.
Under specific request, there is also the possibility to send commands tothe controllers over the serial connection instead of the analog inputs.

Fig. 8.j: UC55 controller board

The UC55 control board is plugged as a daughter board into amplifierboard and integrates a single channel digital controller that achievescontrol rate in accordance with CTEC mechanism.
In single channel, the control rate is 30 kSps, in dual channels, 15 kSps,
and in triple channels, 10 kSps. The UC55 boards can also be stacked tohandle several independent control channels at high frequency (up to 3).

PARAMETER

UNIT

UC55

> General

Function
Number of control channels
Digital communication

Digital controller with analog I/Os
1…3
USB

Graphical User Interface

CTEC HDPM> Digital control

Control strategy
Sampling rate
Digital resolution

kSps
bits

Tunable PID + Stabilising filters
10 / 15 / 30 (k.1)
16V-10 ... +10V-10 ... +10> Analog inputs

Analog inputs voltage range> Analog outputs

Analog outputs voltage range> Miscellaneous

Product compatibility

LA75 and SA75 series
Table 8.k Characteristics of UC55 controller boards

k.1 10kSps for 3 channels, 15kSps for 2 channels, and 30kSps for 1 channel

Products Catalogue Version 5.1 - Drive Electronics & Controllers

8.1.7. CUSTOMISED AMPLIFIERS AND CONTROLLERSLINEAR CHARGE AMPLIFIERThis linear charge amplifier based
powered rack is derived from thelinear voltage amplifier board LA75B.
The piezo actuator is driven withelectric charge instead of voltage inorder to reduce the hysteresis effectbelow 1 % in open loop and dynamic
conditions. This charge amplifier
option is available for LA75A and B
boards under request. (see Fig. 8.kand Fig. 8.l)

MULTICHANNEL LA75C
POWERED 19’’ SUB-RACKCABINETThis combination of 4 LA75C
with SG conditioner and digital
controller boards is implemented
inside a RK84F-9U cabinet in orderto drive and to control in push pullconfiguration some large piezo
Tip Tilt, XY stages or fast steering
platforms. (see Fig. 8.m)

HIGH VOLTAGE MULTICHANNELAMPLIFIER RACKThis 18 channels combination
allows to drive simultaneously
18 high voltage piezo actuators(from -200 to +200 V) (see Fig. 8.n)Fig. 8.k: Hysteresis plot of displacement versus input
voltage for a linear voltage amplifier (grey curve)
and for a linear charge amplifier (blue curve)

Fig. 8.l: Schematic of a charge amplifierFig. 8.m: Rack cabinet mounted LA75C
push pull amplifier channels for driving
large capacitance piezo mechanism

Fig. 8.n: 18 amplifier channels rack forhigh voltage piezo actuators

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8.2. AMPLIFIER FORMAGNETIC ACTUATORS
8.2.1. OEM SERIES

Fig. 8.o: MCLA 18

COMPACT LINEAR POWER AMPLIFIER MCLA18

The Compact Linear Power Amplifier MCLA18 is a compact size 2 channels push pull controller box with large output power
capability.
The MCLA18 is relevant for driving & control the motion of either 2 single axes MICA™ or dual axis magnetic actuators like
Magnetic Fast Steering Mirror (M-FSM™) along large operating bandwidth.
PARAMETER (G.1)

UNIT

MCLA18VDC

All-in-one magnetic driver and controller
2
RS422, USB±15 ... ±36

kSps
bits

Floating-point microcontroller
Dedicated control for magnetic mechanism
100
16

V

4
-10 … +10VA
µH

±10 … ±32±10

> General

Function
Number of channel
Digital communication
DC main supply voltage> Digital control

Processor
Control strategy
Sampling rate
Digital resolution> Input

Number of analog inputs
Control input voltage (Vin+ - Vin-)> Output

Output voltage
Continuous output current(g.2)
Minimum output load
> Power amplifier

Number of channels
Max. continuous output apparent
power (g.2)
Max. continuous output active power
Gain

2
VA

32

W
A/V

1 x 32max (or 2 x 16max)
0.1> Protections

Protections

Reverse Polarity, Current Limitation (Amplifier), Overtemperature (Amplifier)
Table 8.g Characteristics of MCLA18

g.1 Guaranted in labs environment
g.2 Depending of the output voltage - See Fig. 8.p

Fig. 8.p: MCLA18 Operating Graph

Products Catalogue Version 5.1 - Drive Electronics & Controllers

COMPACT SWITCHING AMPLIFIER MCSA480
The Compact Switching Amplifier MCSA480 is a compact size 2 channels
push pull controller box with large output power capability (max. 480 VA~ 48 V × 10 A).
The MCSA480 is relevant for driving & control the motion of either 2
single axis MICA™ or dual axis magnetic actuators like Magnetic Fast
Steering Mirror (M-FSM™) along large operating bandwidth (>100 Hz).
Fig. 8.q: MCSA 480

PARAMETER> See MCSA480 full datasheet

UNIT

MCSA480 (G.1)> General

Function
Number of control channels
Digital communication
Graphical User Interface

All-in-one magnetic driver and controller
2
RS422, Ethernet (optional), USB
CTEC HDPM> Digital control

Control strategy
Sampling rate
Digital resolution

kSps
bits

Specific Control
100
16

V

4
-10 … +10

VA

-48 … +48
±7

Vdc

24 … 48> Analog inputs

Number of analog inputs
Control input voltage (Vin+ - Vin-)> Output

Output voltage range (g.2)
RMS output current> Power supply

Supply voltage range> Power amplifier

Number of channels

2> Protections

Protections

Overcurrent (Actuator & Amplifier), Overtemperature (Amplifier), Reverse
Polarity, Overvoltage (input), Undervoltage (input)> Options

Actuator cableSpecific length on request.
Table 8.h Characteristics of MCSA480

h.1 Guaranted in labs environment
h.2 (1) Limited by supply voltage.

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LINEAR POWER AMPLIFIER FORMAGNETIC ACTUATOR CMAµ10
The following linear amplifier is designed to drive inductive loads likemagnetic actuators with extremely low noise. The new CMAµ10 is acompact and standalone unit specially designed for driving magnetic
products such as MICA20CS actuators. The CMAµ10 includes a current
closed-loop control and is ideal for driving small size actuators from CTEC
and other actuators such as voice coils and moving magnet actuators,
for linear or tilting motion.
PARAMETER (I.1)

UNIT

Fig. 8.r: CMAµ10
CMAµ10> General

Function
Number of channel

Driver for magnetic linear actuator
1> Input

Control input voltage (Vin+ - Vin-)

V-10 … +10

V
A
µH

±32
±0.5
100

VDC
VDC

24
±36

VA

16

W

16

A/V

0.05

> Output

Output voltage
Continuous output current (I.2)
Minimum output load
> External power supply

DC main supply voltage
DC additional supply voltage> Power amplifier

Max. continuous output apparent
power (I.3)
Max. continuous output active power> GainGain> Protections

Protections

Current limitation, Overtemperature indicator
Table 8.i Characteristics of CMAµ10

i.1 Guaranted in labs environment
i.2 Depending of the output voltage - See Fig. 8.tFig. 8.s: CMAµ10 Operating Graph

Products Catalogue Version 5.1 - Drive Electronics & Controllers

8.2.2. CUSTOMISED AMPLIFIERS & CONTROLLERS
POWERED CASE CONTROLLER

OEM COMPACT AMPLIFIER BOARD

This powered case includes a DC/DC converter, a linear
amplifier, a positioning sensor conditioner and a controller
boards in order to control a moving coil based mechanism
for high accuracy indent instrument.

This CLAu10 offers a compact linear amplifier board
solution to drive magnetic actuators such as MICA™ orMoving Coil Actuators.

Fig. 8.t: Powered case controller for
driving moving coil mechanism

COMPACT SWITCHING AMPLIFIER CSA96
The Compact Switching Amplifier CSA96 is a compact sizeand large output power amplifier box for driving linear
magnetic actuators like Moving Iron Controllable Actuator(MICA™). This CSA96 box is supplied by an External DC
power supply up to 96 VDC.

Fig. 8.u: CSA96

Fig. 8.v: OEM amplifier board for
driving magnetic actuators

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8.3. CONTROLLER FOR PIEZO MOTORS
Piezo motors always need the combination of a positioning sensor feedback and a controller to be used as accurate
positioners or motion providers within mechatronic system. The piezo motor technology developed by CEDRAT TECHNOLOGIES(CTEC) is called Stepping Piezo Actuator (SPA).

8.3.1. CONTROLLER BOARD FOR STEPPING PIEZO ACTUATOR
The Stepping Piezo Controller SPC45 is a versatile, single channel
controller board offering an off the shelves solution to control
either the Linear Stepping Piezo Actuator LSPA30uXS or the Linear
Stepping Piezo Stage LSPS35XS. The SPC45 controller board
is included in the developer kit and provide the user with many
features in terms of command & control options (step, position),
digital or analog I/O connections as well as a user-friendly graphicalinterface to adjust the motor performances according to the system
integration requirements.
Fig. 8.w: SPC45 piezo motor controller board

PARAMETER

UNIT

SPC45

> General

Number of control channels
Integated sensor conditioning (i.1)
Digital communication
Graphical User Interface (GUI)1
Quadrature encoder interface
USB
CTEC IHM SPC45> Analog inputs

Number of analog inputs
Analog inputs voltage range

V

1
0 ... 5V

1
0 ... 5VA

1
5 ... 96.5
0.15

Vdc
Arms

9 … 24
0.1 … 0.56

kg
mm3

0.11
91 × 66 × 22

> Analog outputs

Number of analog outputs
Analog outputs voltage range> Piezo driver

Number of channels
Nominal output voltage range
Peak output current> Power supply

Supply voltage
Supply current> Miscellaneous

Mass
Dimensions

Table 8.j Characteristics of SPC45
j.1

Sensor gain adjustable through GUI

Products Catalogue Version 5.1 - Drive Electronics & Controllers

8.3.2. CUSTOMISED CONTROLLERS FOR PIEZO MOTOR BASED MECHANISMS

Fig. 8.x: Controller box for 3 axis piezo motorised mechanism

Fig. 8.y: Controller box for 2 axis piezo motorised mechanism

CTEC had already developed from customer specifications
some piezo motor based mechanisms with several
degrees of freedom requiring multi-channel andcomplex control features (see chapter §6.6. Customised
piezo motor mechanisms, page 89). CTEC custom
designed controller boxes in order to meet the functional
requirements of the customer system.

Fig. 8.s shows a controller box to drive and to control
simultaneously and independently 2 piezo motorised
axes with submicron position repeatability & non colliding
protocol.
Fig. 8.t shows a controller box to drive a compact piezo
motorised sample along 3 degrees of freedom withaccurate tracking & flexibility in motion pattern follow up.

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For more information on this chapter,
please visit these pages:
cedrat-tec.com/products/sensors
cedrat-tec.com/technologies/sensors

Products Catalogue Version 5.1 - Sensors & Conditioners

9. SENSORS & CONDITIONERS
9.1. SELECTION GUIDE
Positioning sensors available on the market can hardly keep pace with the accuracy requirements
when scaling down the mechatronic system.
That is why CEDRAT TECHNOLOGIES (CTEC) has developed different kinds of sensors foranswering to this problematic of accuracy requirements in a compact volume.
To monitor actuator displacement or implement a closed loop control, CTEC offers several
solutions that allow the customer to build a system corresponding to its requirement.
Different kinds of sensor technologies are available:• Strain Gauges (SG) are contact sensors measuring the deformation of the piezo ceramics.
They are a standard option in piezo actuators (APA®, MLA, PPA) and in some piezomechanisms (TT, XY…).
• Eddy Current Probes (ECP) are contactless sensors measuring the distance between thesensor and a target. They are an option for several types of APA© piezo actuators and in somepiezo mechanisms (TT, DTT, XY). They can be used also with magnetic actuators.
Sensor conditioning boards are available for these two types of sensors. They can be implemented
in powered racks in combination with controllers and amplifiers to obtain a complete closed loop
system.
Both technologies are further presented in §9.2. Strain gauges & associated conditioners, page
122 and §9.3. Eddy Current Sensors & associated conditioners, page 124.
CTEC also integrates to its mechanisms other types of sensors from third party manufacturers,
such as incremental magnetic sensors, optical encoders, accelerometers, capacitive sensors,
end-of-stroke detectors, limit switch sensor, thermal sensors, etc (see §9.4. Customised sensors’
solutions, page 128).
Independently from actuators and mechanisms, CTEC manufactures non-contact inductive
sensors for position measurement in the centimeter range as well as long range magnetic
detection systems and acoustic piezo-based Structural Health Monitoring solutions (see §9.4.
Customised sensors’ solutions, page 128).
Please contact CTEC by phone or email at actuator@cedrat-tec.com for more detailed informationand help in the selection of your configuration.

The technical information on this chapter is not contractualand can be changed without prior notice.

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9.2. STRAIN GAUGES & ASSOCIATED
CONDITIONERS
9.2.1. STRAIN GAUGE SENSORS

Fig. 9.a: Strain Gauge on MLA on an APA1000XLThe Strain Gauge (SG) Sensor is a contact sensor which is bonded
onto a proof body to in order to measure its deformation. In CEDRATTECHNOLOGIES (CTEC) piezo actuators, the proof body is generally theMulti Layer Actuator MLA piezo ceramics, although for some cases the
APA® shell can also be used as the proof body.
It allows to monitor the displacement of the actuator and to implementa closed loop control.
Measuring principle:
The SG transforms applied strain into a proportional change of resistance.
The relationship between the applied strain ε (ε =∆L/Lo) and the relativechange of the resistance of a SG is described by the equation:

Fig. 9.b: APA60SM-SG stroke versus voltage in open loop

∆𝑅𝑅
= 𝑘𝑘. 𝜀𝜀𝑅𝑅0

where k is the gauge factor of the SG.

The small variation of strain induces a small variation of the voltage.
In the piezo actuator, it gives an image of the actuator total stroke.
So a wheastone bridge is built using 4 SG in a specific configuration.
This configuration is well known to improve the measurement of small
variations of resistance
The SG sensor is well adapted for applications requiring good resolution
and linearity. These performances are given with the electronics in thenext section (see Fig. 9.b and Fig. 9.c).
Fig. 9.c: APA60SM-SG stroke versus
voltage in closed loop

CTEC has performed a Space Qualification of its process of SG Sensor
bonded on piezo MLA. This Space Qualification has established a highreliability and an excellent time stability of its SG for piezo actuator.
General specifications are given in Table 9.a.

9.2.2. STRAIN GAUGES CONDITIONERSThe SG75 Strain Gauges Conditioner (Fig. 9.d) converts the signal fromthe Strain Gauge sensor. It is implemented on a 19’ board and can
include up to 3 independent channels.
General specifications are given in Table 9.b.
Up to date precision specifications (as regard linearity, drift, etc…) are
given on SG75 datasheet on CTEC website.

Fig. 9.d: SG75

Products Catalogue Version 5.1 - Sensors & Conditioners

PARAMETERUNIT

TYPICAL VALUE> General

FunctionContact sensor using strain gage technology> Electrical

Bridge impedanceBridge excitation

Ω
V

350
2.5 ... 10% FS (a.1)% FS (a.1)% FS (a.1) /°C% FS (a.1) /°C% FS (a.1)

0.01
< 0.5
0.05
0.01
0.01

°C

Mounted on MLA (a.2)
All APA® and PPA except APA30uXS, APA150XXS & APA50XS-75 ... +95> Type of Measurement

Deformation
Resolution
Creep
Thermal Offset drift
Thermal gain drift
Long term stability (30 days)> Miscellaneous

Dimension
Actuator compatibility
Operating temperature range
Compliant with actuator 'vaccum' option
Other interfaces on request

Table 9.a Specifications of Strain Gauge (SG) sensor
PARAMETERUNIT

TYPICAL VALUE> General

Function
Number of channels

Conditionner of strain gage sensor
1…3> Input

Sensor type
Bridge impedanceBridge excitation (b.1)
Gain span (b.2)Ω
V

Full bridge, strain gauge-based, 4 wires
350
5
116 … 2 700

V
kHz

±10
15

% FS (a.1)% FS (a.1)% FS (a.1) /°C% FS (a.1) /°C

0.01
0.01
±0.025± 0.1°C

0 ... 40

> Output

Typical output voltage (b.3)
Bandwidth -3 dB> Accuracy

Resolution
Linearity
Thermal offset drift (b.4)
Thermal gain drift (b.5)> Miscellaneous

Operating temperature range> Included Accessories

Strain Gauge cable

Shielded 1.5 m
Table 9.b Specifications of SG75

a.1 FS: Full Stroke (FS) corresponds to the stroke of the piezoelectric actuator
a.2 MLA: Multi layer Actuator (piezo ceramic)
b.1 Alternative voltage 2.5, 7.5, 10 V available on request
b.2 Other values on request
b.3 Set to [-1 V ; 7.5 V] on CTEC systems to be consistent with driver input
b.4 Could be reduced by deleting the offset adjustement
b.5 Maximum drift with conditionner gain of 1000

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9.3. EDDY CURRENT SENSORS &ASSOCIATED CONDITIONERS
9.3.1. EDDY CURRENT SENSOR PROBES ECP
Eddy Current Sensing (ECS) is a contactless proximity method formeasuring the distance between a probe and a conductive target. It
requires:• an Eddy Current Probe (ECP) placed in front of the Target• an ECS electronic conditioner, as the ECS45, ECS75, ECSu10,
Fig. 9.e: APA500L integrating a naked
ECP500 in front of a target

The measuring principle is shown on Fig. 9.f: the ECP features an
induction coil in which an alternating current is applied. It generates anoscillating magnetic field in the conductive target, in side which eddy
currents are induced. These eddy currents generate an induced magnetic
field the amplitude of which decreases with the distance between thetarget and the probe. This induced field is then detected by the ECP,
giving a signal amplified by conditioner (see §9.3.2. Eddy Current Probe
conditioners ECS, page 126).
From its long experience in magnetic devices design, Cedrat Technologies(CTEC) developed a unique ECP which is extremely compact, thanks to
the direct integration of the inductive coil inside a PCB. This technology
also takes benefit of space qualification, meaning performance androbustness.
The ECP is well adapted for distance measurement requiring higher
resolution, high bandwidth and a contactless sensing area.

Fig. 9.f: Physical principle of an Eddy Current
Sensor probe in front of a target

The ECP is able to sense sub-micron positions in sub-millimeter andmillimeter ranges. High precision is obtained when combined with ECS
conditioners.
For optimal performances, the target should be preferably made ofnonmagnetic conductive materials such as aluminum. Stainless steel isanother candidate but with less sensitivity.
Standards ECP are proposed in two versions with a different measurement
range: 500 µm for the ECP500 and 1000 µm for the ECP1000, but
customized versions can be easily derived. CTEC could adapt ECP for
specific volume with the naked ECP pattern PCB. The “shielded” version
could be provided with straight or right angle output cable.

Fig. 9.g: ECP Probe

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PARAMETERUNIT

ECP500

ECP1000

Preliminary data (c.1)
Eddy Current Sensor

Sensor type
> Electrical characteristics

Range of excitation frequency

kHz

>500

> Mechanical characteristics

Probe diameter
Probe height

mm
mm

8.0

µm
µm

500
1 000

15.0
7.0

> Measurement Range

Nominal range
Extended range

1 000
2 000

> Typical accuracy achieved after conditionning

Resolution (BW = 20 kHz) (c.2)
Resolution (BW = 1 kHz)
Resolution (BW = 20 kHz), extended range (2000 µm)
Resolution (BW = 1 kHz), extended range (2000 µm)% FS (c.3)% FS (c.3)% FS (c.3)% FS (c.3)

0.010
0.003
0.015
0.005

°C

-25 ... +70> Operating Environment

Operating temperature range> Options

Straight / Right Angle cable
Integration on CTEC APA® actuators or mechanisms
Table 9.c Characteristics of Eddy Current Probes

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9.3.2. EDDY CURRENT PROBE CONDITIONERS ECSCEDRAT TECHNOLOGIES’ (CTEC) ECS electronics manage the signal fromthe ECP Eddy Current Probe to provide an information of the probe-totarget distance.
The ECS75 (Fig. 9.j) is a conditioning board implemented on a 19” board,offering up to 3 independent channels, offering linearised sensing
responses. This board can be integrated to the RK42F and RK84F racks
for piezo actuators.
Fig. 9.h: ECSu10

The ECS45 (Fig. 9.i) is a standalone conditioner based on the ECS75,
and so also offering linearized sensing responses.
High precision is achieved considering low linearity error.
ECS75 features a new the “Thermally Stable” design since 2017 instandard. The drift in measured values due to thermal fluctuations of theenvironment is significately reduced. This addresses a major drawbackof the eddy current sensing technologies for these types of environment.
The thermally stable design is also implemented to the ECS45, thestandalone version of the ECS75 which is integrated in a housing
supplied by an external DC power supply.

Fig. 9.i: ECS45 standalone

ECS75 and ECS45 conditioners linearize the output from the ECP probewith a high order polynomial function programmed in a digital component.
The gain of each channel is generally set when the Eddy Current Probe isembedded in the mechanism.
Additionnaly, CTEC proposes a cost-effective and compact OEM
conditioner ECSu10 (Fig. 9.h) that can be easily integrated by thecustomer. It is built around the input analog stage of the ECS75 board
but without the digital stage performing the linearisation and without the
new thermal compensation.

Fig. 9.j: ECS75 board

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PARAMETERUNIT

ECSu10

ECS45

ECS75

Preliminary data

Preliminary data
2

Preliminary data
1…3

CTEC Eddy Current
Probe

CTEC Eddy Current
Probe

CTEC Eddy Current
Probe

Vdc

15 +/-5 %24 +/- 5 %VmA

0 ... 10
4 … 20

±10

±10

kHz

15

20

20

% FS (d.4)

0.005

0.010

0.010

% FS (d.4)

0.008

0.014

0.014

% FS (d.4)% FS (d.4) /°C

±25
0.2

0.1

0.1

Yes

Yes

Number of channels> Input

Sensor type
> Electrical characteristics

Power Supply> Output

Typical output voltage (d.1)
Output current (d.2)
Bandwidth - 3dB (extended onrequest)> Typical achieved accuracy

Resolution (BW = 20kHz) (d.3)
Resolution (BW = 20kHz), extended
range (d.3)
Linearity (d.5)
Thermal drift> OptionsDifferential output (with two probes)

Table 9.d Characteristics of Eddy Current Probe Conditioners ECS

d.1 Set to [-1V ; 7.5 V] on CTEC systems to be consistent with driver input - Could be adjusted with customer specification
d.2 [4-20 mA] output
d.3 BW: Bandwidth
d.4 FS: Full Scale
d.5 Better linearity can be achieved on request

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9.4. CUSTOMISED SENSORS’ SOLUTIONS
9.4.1. CUSTOMISED SENSOR’S INTEGRATION

Fig. 9.k: Linear magnetic encoder (hall effect sensor)

Besides the SG & ECS positioning sensor technologies described in
the previous paragraphs, CEDRAT TECHNOLOGIES (CTEC) have been
integrating other type of sensors available on the market inside its
customised mechatronic systems for decades. This integration covers
mechanical, electronic & control issues.
For instance, CTEC get use to integrate different type of magnetic or
optical encoders (see Fig. 9.k) to provide customers with long range(Several mm) & accurate (micron or nano-meter) positioning control.
CTEC also integrates force, gyros, speed or accelerometer sensors (seeFig. 9.l) for various mechatronic functions such like active stabilization,
tracking, damping, isolation or control of vibrations.
The selection of the sensor and the control strategy will be madeaccording to the customer specifications and application (payload,mechanical structure, environmental and boarding conditions…).
In the frame of our detection systems’ activities, CTEC also integrated
various type of temperature and pressure sensors.

Fig. 9.l: Three axes accelerometer PCB mounted

On top of this sensors’ integration know-how, CTEC develops customised
sensor and detection solutions, as shown in the following paragraph toanswer to customer’s specific needs.

9.4.2. CUSTOMISED MAGNETICSENSORS & DETECTION SYSTEMS
Magnetic sensors offer potential for contactless detection techniques.
These magnetic sensing technologies are recurrently exploited by CTEC
to provide various innovative customized solutions, either as components
or as complete systems.
Fig. 9.m: MC-Suite force sensing table (See cedrat-tec.
com/services/engineering/collaborative-projects)

Its Eddy Current Sensors products are used for high precision motion
control on distance up to 3 mm. They are used in its actuators or for
making customized force & torque sensors as well as top counter
sensors.
In machine tool, force feedback systems are requested to measureforces exerted to the workpiece during the cutting operation. To meet thisdemand, a cost-effective Force Sensing Table with a diameter 100 mm
and a height of 70 mm is capable of measuring forces in one direction
only with a range of ±20 kN, a resolution of 12 N and accuracy of better
than 50 N at 1 kHz.
Following the same approach, three axis force feedback table and Single
axis force feedback tool holder are also developed.

Fig. 9.n: CTS Contactless Torque Sensor

Customized Robust & Cost effective Contactless Torque Sensors (CTS)
have also been developed for automotive and aircraft. The concept isProducts Catalogue Version 5.1 - Sensors & Conditioners

based on a patented torsion converter and an ECS-based proximity
sensor. Different CTS can cover various torques from 1 to 500 N.m, withresolution of 0.1 %.
Using its ECS technology, an accurate contactless top counter sensor has
been space qualified for EUCLID-NISP Cryomechanism for CEA. This
generates a precise top signal at each rotation with an angularrepeatability under +/-0.25° while operating at 20°K in vacuum.
To offer cost-effective contactless solutions for tyre thickness
measurements, 3 different inductive sensor types have been developed
and patented in collaboration with MICHELIN MFP (see Fig. 9.p):• HMP: Hall sensor and Magnet Position sensor

Fig. 9.o: EUCLID-NISP top counter sensor• PCI: Pot shape Coil Inductive sensor• PCT: Planar shape Coil Transformer
They allows distance measurements up to 40 mm, with power as low as
0.3 mW, weight lower than 6 gr, resolution 0.1 mm.
In the frame of ROXTAR medtec project, CTEC has developed an accurate
Magnetic 6 DoF Alignment Localization & Tracking (MALT) system offeringa detection range larger than 1 m.
The MALT system is based on 3 sub-systems:• a magnetic fields emitter and placed on the X Ray emitter• a sensor systems placed in the X Ray detector plate

Fig. 9.p: PCI inductive sensor for MICHELIN MFP• a PC with electronics and a Graphical User Interface (GUI)
Localization resolutions are 0.5mm in horizontal plane, 5 mm along
vertical axis, and 0.1° in angle., within a latency of 300 ms.

Fig. 9.q: 1 meter range MALT for ROXTAR129

CEDRATTECHNOLOGIES
Innovation in Mechatronics

compact dynamic precise

9.4.3. NON-DESTRUCTIVE TESTING NDT &STRUCTURAL HEALTH MONITORING SHM
Non-Destructive Testing (NDT) consists of sensing techniques formaterial, component or system without causing damage. Among them,
Structural Health Monitoring (SHM) is an embedded NDT for detecting
damages of a mechanical structure over time.
Fig. 9.r: Monitoring stress in bridge cable

CEDRAT TECHNOLOGIES (CTEC) has an extensive experience in the fieldof piezo transducers, magnetic generators and sensors as well as theirrelated electronics (driving, sensing, controlling), which served as a basis
to develop powerful NDT or SHM-dedicated electronics solutions.
NDT activities at CTEC consists in developing various acoustic &electromagnetic techniques for dedicated needs, based on:• Piezo actuators, transducers & sensors• Strain gages on specific proof bodies• Specific Eddy Current Sensors

Fig. 9.s: Test bench for SHM : LWDS45
board connected to 2 piezo patches• Reluctance magnetic sensors• Direct magnetostriction effect (occurring when the magnetic
properties are changed with mechanical stress)
These techniques applies on pipelines, ferromagnetic cables, on-line
inspection of rolled steel manufacturing, weigh in motion (WIM), etc
One SHM technique developed by CTEC is to emit and receive ultrasonicwaves with piezo-electrical transducers attached to the structure. The
propagation of the wave is analyzed to evaluate the presence of damages
inside the structure. This ultrasonic detection method is particularly
appropriate to monitor health of large structures whose systematic
inspections are mandatory but costly, such as aircrafts, spacecrafts,
boats, bridges, cables, pipes, etc…

Fig. 9.t: Pulse-echo acoustic signals

The proposed solutions consist in designing piezo patches, driving andsensing electronics, ranging from the pure analog rack to the fully
programmable solution delivered with Graphical User Interface (GUI).
According to the application, operating frequencies varies from 1 kHz to
1 MHz.
For example in Fig. 9.t, a LWDS45 board from CTEC is connected to two
piezo patches. A patch is electrically excited to generate a pulse (see Fig.
9.u). Then the LWDS switches to a listening mode on both patches (pulseecho technique). The detected signals are recorded, and compared toprevious records. If signal changes are detected, it means a damage has
appeared in the plate.
Fig. 9.u shows a 18 channels electronics for piezo patch excitations for
SHM.
For more information on customised sensors’ solutions, please see:cedrat-tec.com/products/sensors/eddy-current-sensors and
cedrat-tec.com/technologies/sensors

Fig. 9.u: 18 channels piezo emission rackProducts Catalogue Version 5.1 - Sensors & Conditioners

131

CEDRATTECHNOLOGIES
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compact dynamic precise

For more information on this chapter,
please visit these pages:
cedrat-tec.com/products/evaluation-kits
cedrat-tec.com/products/piezo-motors

Products Catalogue Version 5.1 - Mechatronic solutions

10. MECHATRONIC SOLUTIONSCEDRAT TECHNOLOGIES (CTEC) also proposes different types of complete mechatronic solutions:• Evaluation and development kits
• Turnkey mechatronic modules
The mechatronic kits can be seen as first plug and play solutions to discover and to practicedifferent aspects of piezo mechatronic for different purposes. For instance, are presented in thefollowing paragraphs:• the Evaluation Pack EP120S: for low cost access and practice of piezo actuator & driver• the Active Control of Vibration ACV educational kit: a set up for educational purpose• the Linear Stepping Piezo Actuator LSPA30uXS, Linear Stepping Piezo Stage LSPS35XS andModular Stepping Piezo Actuator MSPA35XS developments kits: three kits to experienceminiaturised SPA motors with various integration levels combined with their associatedStepping Piezo Controller SPC45.

The technical information on this chapter is not contractualand can be changed without prior notice.

133

CEDRATTECHNOLOGIES
Innovation in Mechatronics

compact dynamic precise

10.1. EVALUATION PACK EP120S
The Evaluation Pack provides with an easy evaluation of CEDRATTECHNOLOGIES’s (CTEC) piezo offer in quasi static conditions. It includes:• An Amplified Piezoelectric Actuator APA120S• A linear amplifier CAu10• Related cables
The APA120S can bear load up to 0.5 kg over 140 μm, in a compact size.
Fig. 10.a: Evaluation Pack EP120S:
APA120S actuator & CAu10 amplifier

The CAu10 can deliver a voltage up to 150 V and has 2 channels.
Please refer to the datasheet of APA120S actuator and CAu10 amplifier
for technical specifications and drawings.
The typical diagram stroke/frequency of the EP120S is presented in Fig.
10.b:
The main features enlightened by the evaluation pack are:
• A high stiffness of the actuator• A nanometer resolution• A good repeatability• An excellent reliability

Fig. 10.b: Stroke / frequency of the EP120S• An easy implementation• A low cost of ownership

Products Catalogue Version 5.1 - Mechatronic solutions

10.2. EDUCATIONAL KIT ACV - ACTIVE CONTROL OF
VIBRATIONS
A real opportunity for students to discover mechatronics, control andpiezoelectricity.
The education kit ACV (Active Control of Vibration) includes:• A beam equiped with an accelerometre at the tip• A magnetic exciter able to move the beam on a large bandwidth• Related cables
In the actual industry, a growing number of enquiries deals withmechatronics and particularly Active Control of Vibrations. Stabilisationof wafers during lithography process, noise reduction of helicopter
blades, elimination of motion blur in optical devices, damping of machine
tool vibrations… are few examples of industrial applications.
The kit contains an original and innovative APA®, patented technology
from CTEC attached to a mechanical beam. When the beam is excited by
the magnetic shaker, the vibrations are measured with an accelerometer.
The control is realised with an industrial driver & controller from CTEC
using variable PID parameters and output filters. The controller drives thepiezo actuator in order to cancel the vibrations of the beam. The result isvery visual and impressive!
Developed with CETIM, a centre of excellence in mechanics, SUPMECA
and Polytech Annecy-Chambéry, two recognised engineering schools, itfits the curricula of many engineering courses, especially the ones in
the forefront of mechanics, mechatronics, control systems and industrial
data processing. Control parameters are directly available to students.
Several practical works from 4 to 8 hours developed by teachers areavailable for download on cedrat-tec.com/mechatronic-products/evaluationkits/educational-kit-acv. It is easy and fast to set up. The treated topics are
required know how for engineers: system analysis, PID control, signal
post treatment, modal analysis...
Similarly to the whole range of products of CTEC, the kit is extremely
robust. It is well protected against mishandlings which relieves students
and teachers when using the material.
The educational kit received the first price in the University Challenge
2011 organised by Bruel&Kjaer for the project relative to “Study andcontrol of the vibration behaviour of a ski”.

Fig. 10.c: Educational kit ACV

Fig. 10.d: Vibration damping with ACV kit

135

CEDRATTECHNOLOGIES
Innovation in Mechatronics

compact dynamic precise

10.3. PIEZO MOTOR DEVELOPER KITS
10.3.1. LSPA30UXS PIEZO MOTOR DEVELOPER KIT
The LSPA30uXS (Linear Stepping Piezo Actuactor) developer kit offers
the possibility to discover the potential of the LSPA30uXS, the smallest
existing LSPA, in stepping mode. The developer kit is a plug and playsolution. It allows to learn quickly how to use the LSPA motor.
Fig. 10.e: Components of the LSPA30uXS developer kit

With the included small driver (Stepping Piezo Controller SPC45) and ahigh resolution magnetic sensor, the developer kit is a fully closed-loop
solution allowing a high resolution millimeter-stroke motion (see §8.3.1,
page 116 for more information on the piezo controller itself).
The LSPA30uXS developer kit is made of the following items (Fig. 10.e):• LSPA30uXS on platform: LSPA30uXS mounted on 30×25 mm platform
and coupled with a 2 µm resolution position sensor• SPC45 driver• SPC45 power supply

Fig. 10.f: LSPA30uXS• Cables• USB cable for GUI control on PC
LSPA30uXS performances when coupled with SPC45 are presented inTable 10.a. The LSPA30uXS motor can be extracted from the holding
platform and integrated directly onto the user’s test bench. LSPA30uXS
characteristics can be found in §6.1, page 84.

10.3.2. LSPS35XS PIEZO MOTOR DEVELOPER KIT
The LSPS35XS (Linear Stepping Piezo Stage) developer kit offers thepossibility to discover the potential of the LSPS35XS stage in stepping
mode.
The LSPS35XS stage is a guided stage, which includes a position sensor
and easy mechanical interfaces (see §6.2, page 6.2). Using the included
small driver (SPC45), this kit is a fully closed-loop solution for highresolution millimeter-stroke motion (see §8.3.1, page 116 for more
information on the piezo controller itself).
Fig. 10.g: Components of the LSPS35XS developer kit

The LSPS35XS developer kit is made of different sub-systems (Fig. 10.g):• LSPS35XS piezoelectric stage• SPC45 driver• SPC45 Power Supply• Cables• USB cable for GUI control

Fig. 10.h: LSPS35XSLSPS35XS performances when coupled with SPC45 are presented inTable 10.a.

137

Products Catalogue Version 5.1 - Mechatronic solutions

10.3.3. MSPA35XS PIEZO MOTOR DEVELOPER KIT
The MSPA35XS (Modular Stepping Piezoelectric Actuator) developer kit
offers the possibility to discover the flexibility of the MSPA piezoelectricmotors in stepping mode.
The MSPA35XS developer kit includes a standard MSPA35XS
piezoelectric stage combined with a small driver (SPC45). When pressedagainst a guided payload, the MSPA35XS generates a driving force
making it moving.
The MSPA35XS developer kit is made of different sub-systems (Fig. 10.i):

Fig. 10.i: Components of the MSPA35XS developer kit• MSPA35XS piezoelectric stage• SPC45 driver• SPC45 power supply• Cables• USB cable for GUI control
MSPA35XS performances when coupled with SPC45 are presented inTable 10.a.
Fig. 10.j: MSPA35XS

A typical example that can be achieved using the MSPA35XS developer
kit is to drive a commercial bearing as shown in Fig. 10.k.

Fig. 10.k: Example of MSPA35XS use

PARAMETERUNIT

LSPA30UXSLSPS35XSMSPA35XS

mm
mm/s
µm
N/µm

3.4
20

10

∞ (a.1)

0.09

N
N

0.8
0.2

> Stepping mode

Travel range
Nominal Speed (a.2) (a.3)
Typical step size (a.2) (a.3)
Stiffness10
5 … 305 … 200.50> Forces

Holding force without consumption
Nominal driving force (a.2) (a.3)

3
0.8> DriverNominal driver

SPC45
Table 10.aa.1 Limited by moving parta.2 Unloaded
a.3 With nominal driver

Characteristics of developer kits coupled with SPC45

0.5

compact dynamic precise

CEDRATTEC
HNOLOGIES
Innovation in Mechatronics

Actuator

Voltage

Position

Ampliﬁer

Sensor conditioner

Controller

Order X

For more information on this chapter,
please visit these pages:
www.cedrat-technologies.com
cedrat-tec.com/products/users-manual/electronics

Products Catalogue Version 5.1 - Application notes

11. APPLICATION NOTES
11.1. YOUR OWN APPLICATION SELECTION GUIDECEDRAT TECHNOLOGIES (CTEC) can help you select the right combination of actuator and driver.
Try to answer the following questions and share your specifications by email or by phone.
• Maximum displacement required for my application• Required bandwidth (At which frequency do I want to drive the actuator ?)• Required actuation time
• Size (What volume and dimensions are allowed for the actuator in my application ?)• Mass to be moved by the actuator (What is the inertia ?)• Forces acting on the actuator:• Spring loading (Is my actuator loaded by a spring? What is the spring’s stiffness?)• Presence of other forces like gripping, viscosity, etc…?
• Position sensor (Do I need to monitor and/or control the motion/ the position?)• Motion resolution required• Motion accuracy required• Environment:• Temperature range• Humidity• Vacuum• Vibration shock• Magnetic field compatibility

See Table 11.a and Table 11.b next page for electronic selection.

The technical information on this chapter is not contractualand can be changed without prior notice.

139

compact dynamic precise

CEDRATTEC
HNOLOGIES
Innovation in Mechatronics

ELECTRONIC SERIE

Continuous peakoutput current (mA)
Transient peakoutput current (mA)
ACTUATOR
SERIE

CAU10

CCBU20

LA75A

LA75B

LA75C

SA75A

SA75B

SA75D

5

200

90

360

2 400

5 000

10 000

20 000

-

-

300

1 100

8 000

-

-

-

CAPACITANCE(µF)

CHARGING TIME @ 170 V (MILLISECONDS) (A.1)> MLA serie

MLA 2×5×10
MLA 5×5×10
MLA 5×5×20
MLA 10×10×20
MLA 14×14×20

0.25
0.7
1.55
6.6
12

8.5
24
53
224
408

0.2
0.6
1.3
6
10

0.14
0.4
1.5
11.1
21.3

0.04
0.11
0.2
1.9
4.4

0.01
0.01
0.03
0.1
0.3

0.15
0.15
0.15
0.25
0.4

0.15
0.15
0.15
0.2
0.27

0.15
0.15
0.15
0.18
0.23

0.052
0.15
0.25
1.55
3.15
10
20
40
110

1.8
5.1
8.5
53
107
340
680
1 360
3 740

0.04
0.1
0.2
1.3
2.7
8.5
17
34
94

0.03
0.09
0.1
1.5
4.6
17.5
36.4
74.2
206

0.01
0.02
0.04
0.2
0.5
3.5
8.2
17.7
50.7

0.001
0.003
0.01
0.03
0.1
0.2
0.4
1.4
6.4

0.15
0.15
0.15
0.15
0.15
0.35
0.58
1.2
4

0.15
0.15
0.15
0.15
0.15
0.25
0.38
0.67
1.83

0.15
0.15
0.15
0.15
0.15
0.22
0.28
0.42
0.88

0.7
1.4
2.7
13.3
20
26.6
24
48
72

24
48
92
452
680
904
816
1 632
2 448

0.6
1.2
2.3
11
17
23
20
41
61

0.4
1.2
3.7
24
36
49
44
89
135

0.11
0.2
0.4
5
8.2
11
10
21
33

0.01
0.03
0.1
0.3
0.4
0.6
0.5
2.0
3.7

0.15
0.15
0.15
0.42
0.58
0.72
0.67
1.52
2.48

0.15
0.15
0.15
0.29
0.38
0.46
0.43
0.8
1.2

0.15
0.15
0.15
0.24
0.28
0.33
0.31
0.47
0.63

> APA® serie

APA - µXS
APA - XXSAPA - XS
APA - S, SM
APA - M
APA - MMLAPA - ML
APA - L
APA - XL> PPA serie

PPA10M
PPA20M
PPA40M
PPA40L
PPA60L
PPA80L
PPA40XL
PPA80XLPPA120XL

Table 11.aCharging time comparison between drivers (a.2)

a.1 Values computed according to transient peak output current / See EPC application notea.2 Warning these values are given for electrical limitation. Thermal and mechanical limitations of the actuator are not taken into account141

Products Catalogue Version 5.1 - Application notes

ELECTRONIC SERIECAU10CCBU20

LA75A

LA75B

LA75C

SA75A

SA75B

SA75D

5

200

90

360

2 400

5 000

10 000

20 000

-

-

300

1 100

8 000

-

-

-

Continuous peakoutput current (mA)
Transient peakoutput current (mA)
ACTUATORSERIE

CAPACITANCE(µF)

MAXIMUM FREQUENCY (SINUS) @ 170 VPP (HZ) (B.1)> MLA series

MLA 2×5×10
MLA 5×5×10
MLA 5×5×20
MLA 10×10×20
MLA 14×14×20

0.25
0.7
1.55
6.6
12

40
10
10
1.4
0.8

300
110
50
10
10

670
240
110
26
14

2 700
960
430
100
56

17 980
6 420
2 900
680
370

- (b.2)- (b.2)- (b.2)
1 420
780- (b.2)- (b.2)- (b.2)
2 840
1 560

- (b.2)- (b.2)- (b.2)- (b.2)
3 120

0.052
0.15
0.25
1.55
3.15
10
20
40
110

180
62
37
6
3
1
0.5
0.2
0.1

1440
500
300
50
20
10
4
2
1

3 240
1 120
670
110
53
17
8
4.2
1.5

12 960
4 490
2 700
430
210
67
34
17
6

- (b.2)29 96017 980
2 900
1 430
450
220
110
40

- (b.2)- (b.2)- (b.2)- (b.2)
2 970
940
470
230
90

- (b.2)- (b.2)- (b.2)- (b.2)- (b.2)
1 870
940
470
170

- (b.2)- (b.2)- (b.2)- (b.2)- (b.2)
3 740
1 870
940
340

0.7
1.4
2.7
13.3
20
26.6
24
48
72

10
10
3
1
0.5
0.4
0.4
0.2
0.1

110
50
30
10
4
3
3
2
1

240
120
60
13
8
6
7
3.5
2.3

960
480
250
51
34
25
28
14
9

6 420
3 210
1 660
340
220
170
190
90
60

- (b.2)- (b.2)
3 470
700
470
350
390
200
130

- (b.2)- (b.2)- (b.2)
1 410
940
700
780
390
260

- (b.2)- (b.2)- (b.2)
2 820
1 870
1 410
1 560
780
520

> APA® serie

APA - µXS
APA - XXSAPA - XS
APA - S, SM
APA - M
APA - MMLAPA - ML
APA - L
APA - XL> PPA serie

PPA10M
PPA20M
PPA40M
PPA40L
PPA60L
PPA80L
PPA40XL
PPA80XLPPA120XL

Table 11.b

Maximum frequency comparison between drivers (b.3)

b.1 Values computed according to continuous peak output current
b.2 Please contact CTEC for this configuration
b.3 Warning these values are given for electrical limitation. Thermal and mechanical limitations of the actuator are not taken into accountcompact dynamic precise

CEDRATTEC
HNOLOGIES
Innovation in Mechatronics

11.2. BUILDING A GENERAL PIEZOELECTRIC ACTUATOR MODEL
The principal task before controlling a piezo actuator is tobuild a model integrating the parameters of the actuatorfrom the catalogue. This model allows the tuning of thecontroller’s parameters in advanced processes or for an
optimal control. Several parameters are given inside andrecalled below:• Effective Mass: M+m (Kg) actuator mass plus
additional embedded mass
• Resonant frequency: fr (Hz) first mode computed withthe stiffness and effective mass:

𝑓𝑓𝑟𝑟 =• Stroke: ΔU (m).

• Voltage: V (V), output voltage provided by the electronic
amplifier on the piezo actuator.

• Voltage: Vmax (V) maximal voltage applied on the piezo
actuator to reach the maximal stroke.

• Blocked force: F0 (N), maximum force generated by theactuator with no displacement at maximum voltage Vmax
• Force factor: N (N/V), force per voltage unit:

𝐹𝐹0
𝑁𝑁 =
𝑉𝑉𝑚𝑚𝑚𝑚𝑚𝑚• Stiffness: K (N/m), displacement ΔU under an applied
force F:𝐾𝐾𝐾𝐾 =𝐹𝐹𝐹𝐹0∆𝑈𝑈𝑈𝑈0

Elasticity is the opposite of stiffness:

𝑐𝑐𝑐𝑐𝑚𝑚𝑚𝑚 =1
𝐾𝐾𝐾𝐾

Cm can be seen as equivalent capacitance in the
motional equivalent circuit.

1𝐾𝐾√
2𝜋𝜋 𝑀𝑀 + 𝑚𝑚

• Quality factor: Q indicates a rate of energy dissipation
relative to the oscillation frequency:

𝑄𝑄𝑄𝑄𝑚𝑚𝑚𝑚 =12𝜋𝜋𝜋𝜋 𝑓𝑓𝑓𝑓𝑟𝑟𝑟𝑟 𝑐𝑐𝑐𝑐𝑚𝑚𝑚𝑚 𝑟𝑟𝑟𝑟𝑚𝑚𝑚𝑚

rm is the resistance in the motional equivalent circuit.
The quality factor of piezo actuators depends on signal
amplitude and boundary condition and then can varyfrom 20 to higher than 100.
From these parameters and as the actuator is driven involtage the transfer function of this continuous plantcan be written:
𝑇𝑇𝑇𝑇𝑇𝑇𝑇𝑇(𝑗𝑗𝑗𝑗𝑗𝑗𝑗𝑗) =∆𝑈𝑈𝑈𝑈𝑁𝑁𝑁𝑁𝑁𝑁𝑁𝑁𝑚𝑚𝑚𝑚=(1 + 𝑗𝑗𝑗𝑗𝑗𝑗𝑗𝑗𝑟𝑟𝑟𝑟𝑚𝑚𝑚𝑚 𝑁𝑁𝑁𝑁𝑚𝑚𝑚𝑚 − 𝑗𝑗𝑗𝑗 2 𝑁𝑁𝑁𝑁𝑚𝑚𝑚𝑚 (𝑀𝑀𝑀𝑀 + 𝑚𝑚𝑚𝑚))
𝑉𝑉𝑉𝑉

The generic model is a second order filter with high quality
factor. When multi mode mechanisms are used, the plantmust contain each mode built with the same formulae.
Of course, this model is a rough model excluding thenonlinearities of the piezo actuator such as the hysteresis,
the creep effect and other non linear effects. Nevertheless,this model can be used to design the control loop.

Products Catalogue Version 5.1 - Application notes

11.3. POSITIONING CONTROL OF PIEZO ACTUATORS
Once you have built your actuator model, the next step isto build your control strategy. Most of piezo actuator’s
applications require a closed loop positioning control
based on a positioning sensor (Strain gages, Contactless
position sensor, etc…) feedback and a controller including
filters and regulator or specific algorithm. This position
control is mandatory to get rid-off the multiple non-linear
effects of a piezo actuator such as hysteresis, creep, gain
variation with temperature, etc… in order to achieve a highlevel of positioning accuracy, repeatability and stability
required by the user system.

In terms of control strategy, Cedrat Technologies (CTEC)
can propose its digital control board with various control
solutions from the standard PID linear regulator (see Fig.
11.a) to the most sophisticated non linear algorithm inorder to satisfy different motion control demands met
in micro-scanning, tracking and stabilisation functions
to name but a few. For basic control solution of piezo
actuators based on PID regulator and filters, CTEC
published the application note below in order to help theuser to optimise and to make the control parameters
more robust. It is based on the HDPM GUI proposed in thestandard UC product.
See application note on position control of piezo actuators:
cedrat-tec.com/products/users-manual/electronics.html

Fig. 11.a: Step response of a piezo actuator withand without optimised PID closed loop143

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CEDRATTEC
HNOLOGIES
Innovation in Mechatronics

11.4. EPC: ENHANCED PEAK CURRENT
LA75B (Voltage)

An enhanced peak current capability for LA75 series
allows faster actuator charging thanks to a larger output
current during a limited time. This feature increases thepower bandwidth as well for low repetition rate signals.

140
120

Actuator Voltage (V)In the upgraded LA75 product a new function called
Enhanced Peak Current is added to fast charge actuators
actuators.

160

100
80
60
40
20
0
-20 0

1

2

3

-40

4

5

Time (ms)A piezo charge is like a capacitor. Due to this behavior,driving at large frequency demands large currents fromthe specific driver:Standard

Enhanced Peak Current

Fig. 11.c: Actuator’s voltage with andwithout peak current capability

LA75B (Current)
1,20

See application note on Enhanced peak current for linear
amplifiers :cedrat-tec.com/products/users-manual/electronics.html

1,00

Actuator Current (A)CTEC has developed a solution able to provide morecurrent during short time to respond to this problematic.
A dedicated Application Note is proposed to understandthe details of the behavior of such electronic capability inregards of your need.

0,80
0,60
0,40
0,20
0,00
-0,20

0

1

2

3

4

Time (ms)Standard

Enhanced Peak Current

Fig. 11.b: Actuator’s current with andwithout peak current capability

5

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Products Catalogue Version 5.1 - Application notes

INDEX
Accuracy, relative andabsolute:
§ 11.3 p.143
Amplified Piezoelectric
Actuators (APA®):§ 1.3.2 p.10;§ 4.2 p.60
Amplifier:
§ 8.1 p.102;§ 8.2 p.112
Blocked force:
§ 11.2 p.142
Charging time:
§ 2.1.10 p.25
Controller:
• CCB:
§ 8.1.1 p.102• UC55:
§ 8.1.6 p.110
LC converter:
§ 8.1.2 p.104;§ 8.1.3 p.106
Current limitation:
§ 2.1.10 p.25;§ 2.2.8 p.34
Drift or creep:
§ 2.1.10 p.25;§ 11.2 p.142;§ 11.3 p.143

FSPA:
§ 6.5 p.88

Repeatability:
§ 11.3 p.143

Life time:
§ 2.1.9 p.22

Resonance frequency:

Multilayer Actuators(MLA):
§ 4.3 p.70
MSPA:
§ 6.3 p.86

• Free-free:
§ 2.1.9 p.22
• Blocked-free:
§ 2.1.9 p.22

Operation modes:

Settling time:
§ 2.1.8 p.21;§ 2.1.10 p.25

• Dynamic strain (DS):
§ 2.1.9 p.22;§ 3.2 p.45

Stepping Piezo Stage(SPS):
§ 6.2 p.85

• Dynamic force (DF):
§ 2.1.9 p.22;§ 3.2 p.45

Stepping Piezo
Actuators (SPA):
§ 1.3.3 p.10;§ 6.1 p.84;§ 6.4 p.87;§ 6.3 p.86;§ 6.5 p.88

• Static (S):
§ 2.1.9 p.22;§ 3.2 p.45
• Impulse:
§ 2.1.9 p.22;§ 3.2 p.45
• Quasi-static:
§ 2.1.8 p.21;§ 2.1.9 p.22;§ 2.1.10 p.25
• Resonant (R):
§ 2.1.8 p.21;§ 11.2 p.142

Effective mass Meff:
§ 2.1.8 p.21;§ 11.2 p.142

Parallel Pre-stressed
Actuators (PPA):
§ 1.3.1 p.10;§ 4.4 p.71

FAPS:
§ 5.8 p.80

Preliminary data:
§ 3.1 p.43

FPS:
§ 5.7 p.80

Pre-load & pre-stress:
§ 2.1.9 p.22

Force limitation:
§ 2.1.9 p.22;§ 2.1.10 p.25

Proof-Mass Actuators(PMA):
§ 3.2.4 p.51

Stiffness: § 2.1.5 p.18;§ 2.1.7 p.20;§ 11.2 p.142
Stroke: § 11.2 p.142

147

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Even though CEDRAT TECHNOLOGIES S.A. makes every effort to guarantee the accuracy of the content of its catalogue, theinformation may be incomplete or, technically inaccurate or may contain typographical errors. Accordingly, the information
provided may be corrected or changed by CEDRAT TECHNOLOGIES SA at any time and without prior notice.
CEDRAT TECHNOLOGIES S.A. may, at any time and without prior notice, change or improve the products and services offered.
CEDRAT TECHNOLOGIES S.A. disclaims all liability for any information, inaccuracy or omission in its catalogue. CEDRATTECHNOLOGIES S.A. shall bear no liability for any decision made on the basis of the said information.
The reproduction or use of the information (texts, pictures, diagrams …) published by CEDRAT TECHNOLOGIES S.A. in thiscatalogue is authorised solely for personal and private use. Any reproduction or use of this information for other purposesis strictly prohibited.
All rights reserved © Copyright February 2023
CEDRAT TECHNOLOGIES S.A. - Meylan, France.

Products Catalogue Version 5.1 - Application notes

NOTES

149

CEDRATTECHNOLOGIES
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compact dynamic preciseCEDRAT TECHNOLOGIES (CTEC) offers off-the-shelfmechatronics products including piezoelectric &magnetic actuators, motors, mechanisms, transducers
and sensors with corresponding drivers & controllers.
These mechatronics products are used for scientific andindustrial applications requiring fonctions such as: micro
and nano positioning, generation of vibrations, microscanning, fast & precise motion control, active control ofvibrations, and energy harvesting...
Most of the products are available in OEM versions for low
cost and high volume industrial applications. CTEC alsooffers services including, design, R&D under contract andtraining.
CTEC is a SME located in Meylan, Inovallée, the French
Innovation Valley near Grenoble. CTEC is recognised asa highly innovative company and has received several
awards.

CEDRAT TECHNOLOGIES
59 Chemin du Vieux Chêne - Inovallée
38246 Meylan Cedex+33 (0)4 56 58 04 00
www.cedrat-technologies.com

CEDRATTECHNOLOGIESInnovation in Mechatronics