sensors and actuators

1. PRESENTATION
Piezoelectric Sensors &
Actuators: Piezoelectric
Materials and properties
– Modes of deformation
– Multimorphs –
Environmental effects
INSTRUCTOR DR MANU SRIVASTAVA
MAM

2. TEAM MEMBERS
20BEC028 SHARATH
20BEC037 DUGGE SHASHIDHAR
20BEC038 FAIYZULLA SHAIK
20BEC099 SAURABH KUMAR SINGH
20BCS211 SHUBHAM TIWARI

4. Piezoelectric actuators are transducers that convert
electrical energy into a mechanical displacement or stress
based on a piezoelectric effect.
They have been used widely as a high precision positioning
mechanism since it can control a small mechanical
displacement at high speed, with the advantages of large
generated force, stable displacement, and ease of use.
However, problems include insufficient displacement and
the large voltage up to a few hundred volts, which is needed
.
Piezoelectric actuators can be designed either as
piezoelectric bimorph actuators or as linear actuators
employing a lever mechanism.
PIEZOELECTRIC ACTUATORS

5. PIEZOELECTRIC SENSOR
piezo sensors detect changes in the environment and
convert them into electrical energy.
A piezoelectric sensor senses mechanical changes in
the environment and produces a useable electrical
signal output, which can be used to measure the
mechanical changes or generate displacement with the
electrical output.
Piezo sensors take on two forms to accomplish this:
active and passive.
These piezo sensors operate below their resonant
frequency for maximized range.
Piezoelectric sensors are mostly used in measuring
vibrations, acceleration, strain, force, and movement.

6. What is
Peizoelectric
Effect?
Piezoelectric effect is when compressing a piezoelectric material produces
electricity.
It occurs when there is a conversion of kinetic or mechanical energy due to
crystal deformation, into electrical energy. Piezoelectric materials are
materials that can produce electricity due to mechanical stress. When a
piezoelectric material is placed under mechanical stress, there is a shift of
the positive and negative charge centers in the material, which then
results in an external electric field. Going the other direction, with an
inverse piezoelectric effect, an external electric field causes a physical
deformation in a piezoelectric material.

7. Peizoelectric
Sensors
A piezoelectric sensor senses mechanical changes in
the environment and produces a useable electrical
signal output

9. TYPES OF PIEZOELECTRIC SENSORS
1.Sonic Sensor
2. Mega-sonic Sensor
3. Ultrasonic Sensor
4. Lead-type Sensor
5. Pin-type Sensor
6. Pressure Sensor
7. Force or Load Sensor
8. Accelerometer Sensor
9. Mechanical Sensor
10. Electrical Sensor
Some of the well known piezoelectric sensors

10. Sonic sensor
Sonic Sensor (as one of the Piezoelectric
Sensor Types)
Sonic sensors are devices used to detect
(and characterize) bodies or objects based
on acoustic waves or vibrations released
from the object.
For sonic sensors, the acoustic waves that
can be detected by this piezoelectric
device are those which fall within audible
range .
.

11. Sonic sensor:
Sonic sensors are used for a variety of purposes,
among which geologic exploration is a prominent
example. The sensor may operate by emitting
acoustic signals which are reflected back to the
device on collision with objects in their path.
When these reflected signals are received, their
characteristics can be analyzed to derive
information about the objects that have been
detected

12. Ultrasonic:
2). Ultrasonic Sensor (as one of the Piezoelectric
Sensor Types)Ultrasonic piezoelectric sensor is used to
detect acoustic waves that vibrate at very high
frequencies above the audible range; which is typically
above 20 kHz [2].This category of acoustic waves is
often referred to as ultrasound.
Piezoelectric ultrasound works on the basis of the
piezoelectric effect; whereby electricity is generated as
a result of mechanical (vibratory) stresses created
when acoustic waves interact with a material.
The high-frequency operation of ultrasonic piezoelectric
sensors, makes them capable of being utilized under a
broad range of conditions, and for a variety of
purposes.It is important to note that ultrasonic sensors
differ from ultrasonic transducers; which are capable of
generating their own ultrasound waves.

13. Mega sonic
Mega-sonic Sensor:
Mega-sonic sensors operate based on the
same principles as sonic and ultrasonic
sensors, but are designed to detect acoustic
waves or vibratory stresses at high frequency
than ultrasonic waves.
These acoustic waves are called mega-sonic
waves, and may vibrate at frequencies that
exceed 1000 kHz.

14. Lead-type Sensor
Lead-type sensor is a type of piezoelectric sensor that
uses lead materials like lead zirconate titanate (PZT) as
the main piezoelectric material.The piezoelectric
material in this sensor is usually connected to electric
cables which help with current transmission.

15. Pin type
Pin-type Sensor (as one of the Piezoelectric Sensor
Types)Pin-type piezoelectric sensor also uses lead
compounds as the main piezoelectric materials.
However, the connection design of this type is slightly
different from that of lead-type sensor. In place of
cables, metal pins are used for current transmission.
Pin-type and lead-type sensors are generally equal in
performance, principle and capacity.

16. Pressure sensor
Pressure Sensor:
Piezoelectric pressure sensor is a type of piezoelectric
sensor that is used to evaluate changes in dynamic
pressure conditions within a given environment,
medium or body.The accuracy of this type of
piezoelectric sensor is dependent on its sensitivity to
mechanical stress. Its operation is based on the linear
proportional relationship between pressure and
electricity generation (estimated in terms of current and
voltage).

17. Force or load sensor
Force or Load Sensor (as one of the Piezoelectric
Sensor Types)Piezoelectric force sensor is a type of
piezoelectric sensor that is used specifically to detect
and estimate strain, stress, or mechanical load.This
type of sensor is most relevant in situations or events
involving significant amounts of force.The operation of
piezoelectric force sensor is based on the generation of
electrostatic charges from piezoelectric materials when
they are subjected to stres

18. Accelometer sensor
Accelerometer Sensor:
A piezoelectric accelerometer measures or detects
motion through the mechanical changes that occur as a
body experiences changes in speed (also known as
acceleration).Alternatively referred to as a
piezoresistive accelerometer, it works by analyzing
force dynamics like stress and vibration/harmonic
motion, which are set off as acceleration or any
significant mechanical process, occurs.The
piezoelectric accelerometer sensor is often used for
shock testing and pulse measurement or evaluation.
Like other types of piezoelectric sensors, it depends on
the piezoelectric effect, or changes in electric charge
dynamics with changes in stress distribution, for all its
functions.

19. Mechanical Sensor
Mechanical Sensor (as one of the Piezoelectric Sensor
Types)A piezoelectric mechanical sensor is used to
detect changes in mechanical properties or variables
like force and speed or direction of motion.

20. Electrical sensor
Electrical Sensor:
An electrical piezoelectric sensor uses the piezoelectric
effect to analyze the supply and flow of current through
a conductor or energy management system.
An electrical sensor (also called an electronic sensor) is
a device that detects a physical parameter of interest
(e.g. heat, light, sound) and converts it into electrical
signal that can be measured and used by an electrical
or electronic system.

21. Piezoelectric
Actuators
Piezoelectric actuators are transducers that convert
electrical energy into a mechanical displacement or
stress based on a piezoelectric effect

22. Piezoelectric actuators
Piezoelectric actuators are devices that produce a small displacement with a high force
capability when voltage is applied. There are many applications where a piezoelectric
actuator may be used, such as ultra-precise positioning and in the generation and
handling of high forces or pressures in static or dynamic situations.Actuator configuration
can vary greatly, depending on application.
Piezoelectric stack or multilayer actuators are manufactured by stacking up piezoelectric
disks or plates, the axis of the stack being the axis of linear motion that occurs when a
voltage is applied.
Tube actuators are monolithic devices that contract laterally and longitudinally when a
voltage is applied between the inner and outer electrodes.
A disk actuator is a device in the shape of a planar disk. Ring actuators are disk actuators
with a center bore, making the actuator axis accessible for optical, mechanical, or
electrical purposes. Other less common configurations include block, disk, bender, and
bimorph styles.
.

23. Stiffness is a these devices can also be ultrasonic. Ultrasonic actuators are
specifically designed to produce strokes of several micrometers at ultrasonic
(>20 kHz) frequencies.
They are especially useful for controlling vibration, positioning applications,
and quick switching. In addition, piezoelectric actuators can be either direct or
amplified.
The effect of amplification is not only larger displacement, but it can also result
in slower response times.
The critical specifications for piezoelectric actuators are displacement, force,
and operating voltage of the actuator. Other factors to consider are stiffness,
erm used to describe the force needed to achieve a certain deformation of a
structure. For piezoelectric actuators, it is the force needed to elongate the
device by a certain amount, normally specified in terms of Newtons per
micrometer.

24. Real life usage of piezoelectric actuators

25. Materials used in Piezoelectric sensors
and Actuators
Several common piezoelectric materials are used in various applications due
to their piezoelectric properties
Quartz Crystals Rochelle Salt

26. Lead Zirconate Titanate (PZT)
Polyvinylidene Fluoride (PVDF)
Lead Magnesium Niobate-Lead Titanate (PMN-PT)

27. Properties of piezo electric materials
•High Sensitivity: Piezoelectric materials are highly sensitive to mechanical
changes and can produce electrical signals in response to very small forces or
vibrations. This property allows for precise measurements in sensors.
•Wide Frequency Range: Piezoelectric materials can operate across a wide
range of frequencies, from very low (e.g., seismic sensors) to ultrasonic
frequencies (e.g., medical ultrasound transducers).
•Rapid Response Time: These materials have rapid response times, making
them suitable for applications requiring fast and accurate measurements or
actuation.
•Stiffness and Rigidity: Piezoelectric materials are often stiff and rigid,
allowing for precise control of mechanical movements and vibrations.
.

28. Properties:
•Broad Temperature Range: They can function effectively over a broad
temperature range, from cryogenic temperatures to elevated temperatures.
•Damping Properties: Some piezoelectric materials exhibit good damping
properties, which can be useful in reducing vibrations and noise in
mechanical systems.
•Durability: Piezoelectric materials are known for their long-term stability
and durability when used within their specified operating conditions

29. Piezoelectric sensors play crucial roles in various
industrial applications:
•Engine Knock Sensors: In the automotive industry,
piezoelectric knock sensors are essential for detecting
engine detonation, allowing real-time adjustments to
prevent damage and optimize engine efficiency.
Applications of
piezo electric
sensors

30. Applications of piezo electric sensors
•Pressure Sensors: Piezoelectric pressure sensors
are the preferred choice for measuring dynamic
pressure changes in various applications. They provide
reliable results due to their high-frequency response
and eliminate the need for additional mechanical
components like bellows or diaphragms.

31. Applications of piezo electric sensors
•Sonar Equipment: Sonar systems heavily rely on
piezoelectric sensors to transmit and receive ultrasonic
signals within the 50-200 kHz range. These sensors
offer an ideal frequency response and high power
density, enabling efficient acoustic power transmission
from compact transducers.

32. Applications of piezo electric sensors
Piezoelectric actuators are
integral to a range of
industrial applications,
including:
•Diesel Fuel Injectors:
Stringent emissions
regulations and demands
for quieter, more powerful
engines have driven engine
manufacturers to employ
precisely timed and
metered fuel injections.
Piezoelectric actuators
control small valves within
fuel injectors, allowing for
precise control of high-
pressure fuel flow.
.

33. Applications of piezo electric sensors
•Fast Response Solenoids: In
processes requiring rapid and precise
mechanical actuation, piezoelectric
actuators excel. They offer fast
response, low power consumption,
and compact size, making them an
attractive alternative to
electromagnetic solenoids.

34. Applications of piezo electric sensors
•Optical Adjustment:
Piezoelectric actuators are
employed to adjust optics with
wide frequency responses and
minimal moving parts. This is
crucial in applications such as
optical experiments, adaptive
optics for telescopes, and fiber
optic converters

35. Applications of piezo electric sensors
•Ultrasonic Cleaning:
Piezoelectric actuators are
used in ultrasonic cleaning,
where they agitate solvents
to clean objects with
inaccessible surfaces. They
find applications in medical
procedures like breaking up
kidney stones and dental
plaque removal.

36. Applications of piezo electric sensors
•Piezoelectric Motors: These
motors offer precise and predictable
characteristics, allowing for
controlled expansion and
contraction based on voltage. They
provide nanometer-level precision
and can operate in environments
with strong magnetic fields or
cryogenic temperatures, as seen in
MRI machines and particle
accelerators.

37. Applications of piezo electric sensors
•Stack Actuators: Stacked
piezoelectric elements, known as
stack actuators, are used to achieve
greater displacement for a given
voltage. They excel in various
specialty applications due to
advantages like operation in extreme
conditions (cryogenic or magnetic),
high force generation, rapid response,
and exceptional precision.
Applications include proportioning
valves, electrical relays, optical
modulation, and vibration dampening

38. Advancements of piezoelectric
technology
•Miniaturization: Advances in materials science and
microfabrication techniques have allowed for the
miniaturization of piezoelectric devices. This has led to
the development of tiny sensors, actuators, and
transducers for use in medical implants, consumer
electronics, and microelectromechanical systems
(MEMS).
•Energy Harvesting: Piezoelectric energy harvesting
has gained prominence, allowing the conversion of
ambient vibrations and movements into electrical
energy. This technology is used to power small
electronic devices and sensors in applications where
traditional batteries are impractical, such as in remote
monitoring systems.

39. •Nanotechnology: Nanoscale piezoelectric materials and devices have been
developed, enabling ultra-sensitive sensors, high-resolution imaging, and precise
control of nanoscale movements. This has applications in fields like
nanoelectronics and nanomedicine.
•Piezoelectric Motors: Development of more efficient and compact piezoelectric
motors has led to their use in various applications, such as autofocus mechanisms
in cameras and precision positioning systems.
Advancements of piezoelectric
technology

40. Advancements of piezoelectric
technology
•Biomedical Applications: Piezoelectric technology has found increasing
use in biomedical applications, including ultrasonic imaging, drug delivery
systems, and wearable health monitoring devices. Advances in medical
imaging have been made possible by highly sensitive piezoelectric
transducers.
•High-Frequency Applications: Piezoelectric materials have been
adapted for high-frequency applications, such as in piezoelectric inkjet
printers, where precise and rapid droplet ejection is essential.

41. Advancements of piezoelectric
technology
•Aerospace and Defense: Piezoelectric technology has been applied in
aerospace and defense for applications like acoustic sensors, energy
harvesting in unmanned systems, and precision control of aerospace
components.
•Ultrasonic Cleaning: Ultrasonic cleaning devices, which use
piezoelectric transducers to generate high-frequency sound waves, have
become more efficient and widely used in industries like manufacturing
and healthcare.

42. Advancements of piezoelectric
technology
•Non-Destructive Testing: Advances in piezoelectric
transducer design have improved non-destructive
testing methods for evaluating the integrity of materials
and structures, particularly in industries like aerospace
and manufacturing.
•Wearable Technology: The flexibility and
conformability of certain piezoelectric materials, such as
polyvinylidene fluoride (PVDF), have made them
suitable for integration into wearable technology,
including sensors for health monitoring and motion
detection.

43. Challenges and limitations of
piezoelectric
•Limited Displacement: Piezoelectric actuators often
have limited displacement compared to other actuation
methods, which can be a limitation in applications
requiring large mechanical movements.
•Fragility: Many piezoelectric materials are brittle and
can be susceptible to mechanical damage, limiting their
durability in certain environments.
•Temperature Sensitivity: Piezoelectric materials can
be sensitive to temperature variations, and their
performance may change significantly at extreme
temperatures. Special measures may be required to
maintain stable operation.
•Dependence on Material: The properties of
piezoelectric devices are highly dependent on the
specific material used. Material selection is critical, and
not all materials are suitable for all applications.

44. Challenges:
•Aging: Piezoelectric materials can experience aging
effects, leading to changes in their properties over time.
This is a concern in long-term applications.
•Complex Drive Electronics: Complex drive
electronics and feedback control systems may be
required for precise operation, adding to the complexity
and cost of some piezoelectric applications.
•Size and Weight: While miniaturization has improved,
some piezoelectric devices can still be relatively bulky
and heavy compared to other technologies, limiting
their use in portable or lightweight applications.
•Noise: Piezoelectric actuators can produce acoustic
noise during operation, which may be undesirable in
some applications.
•Environmental Sensitivity: Piezoelectric materials
can be sensitive to environmental factors such as
humidity and chemicals, which can affect their long-
term stability.

45. Future trends of piezoelectric instruments
•Energy Harvesting: More efficient conversion of
mechanical energy into electricity for remote
devices.
•Wearable Technology: Integration of flexible
piezoelectric sensors for health monitoring and
energy generation.
•Biomedical Devices: Enhanced piezoelectric
components for medical imaging, drug delivery, and
implants.
•Nanotechnology: Nanoscale piezoelectric
materials for sensitive sensors and nanoelectronics.

46. Future trends of piezoelectric instruments
•Aerospace and Defence: Applications in sensors,
energy harvesting, and precision components.
•Advanced Robotics: For precise and agile
movements in robotics.
•Communication Devices: Piezoelectric resonators
for improved frequency control.
•Artificial Intelligence (AI): AI-driven optimization for
autonomous adjustments.
•Industry 4.0: Automation and precision control in
manufacturing.
•Green Technologies: Sustainable energy
harvesting from renewable sources.
•Consumer Electronics: Integration in devices for
haptic feedback and energy efficiency.
•Sustainable Energy: Harnessing energy from wind
and ocean waves

47. Real Life Examples:

48. Peizoelctric ceramics in space
As space is increasingly explored, there
is a massive drive to understand this new
environment. For years, NASA has been
testing the viability of utilizing piezo
sensors for impact detection of space
particles and debris. Given the
capabilities of piezo elements, NASA
designed an impact piezoceramic sensor
to detect micrometeoroids and sub-
millimeter orbital debris that cannot
usually be tracked. The impact piezo
sensors work by utilizing thin piezo
strips or piezo plates

49. Piezoelectric Ceramics in Aerospace
Applications
Piezoelectricity is undoubtedly one of the
most beneficial and efficient means of
generating power in virtually any
environment. The electricity generated
via piezoceramic material can be
harnessed to generate movement or
produce electrical signals. In recent
years, space exploration has made large
strides in the implementation of piezo
sensors and piezo actuators in
aerospace applications.

50. Piezoelectric Application by NASA
Piezoelectric ceramics offer a
lens into the unknown in
space. Piezo elements, as
aerospace engineers are
discovering, are the ideal tool
for measuring the
environment and controlling
devices due to their extremely
precise, accurate, and fast
response. Piezo
sensors and piezo
actuators are now at the
forefront of aerospace
applications, and piezoelectric
ceramics will inhabit space for
long to come.

51. Piezoelectric Actuator Used By NASA on
Mars Rover

52. PIEZO DISCS IN ACOUSTIC DEVICES

53. MODES OF DEFORMATION IN
PIEZO-ELECTRIC MATERIALS
1. Longitudinal mode of
deformation:
The longitudinal mode of deformation is one of the
fundamental modes of deformation in piezoelectric
materials. In this mode, mechanical stress and
electric field are applied parallel to the direction of
polarization within the piezoelectric material. This
results in a change in the dimensions of the
material along the same axis as the applied stress
and electric field.

54. 1. Direction of Stress and Electric Field: In the longitudinal
mode, both the mechanical stress and the electric field are
applied along the same axis. This axis is typically aligned with
the direction of polarization within the piezoelectric material. For
example, if the piezoelectric material is poled along the vertical
axis, the stress and electric field are applied vertically.

55. 1. Deformation: When a mechanical stress is applied
in this manner, the piezoelectric material
undergoes dimensional changes along the
direction of the stress. In other words, it gets
compressed or stretched along that axis.
1. Electric Field Generation: Simultaneously, due to
the direct piezoelectric effect, an electric field is
generated within the material along the same axis.
This electric field can be measured across the
material's surfaces.

56. 1. Applications: The longitudinal mode of deformation is commonly used in various
piezoelectric devices and applications. For example:

57. MULTIMORPHS:
Multimorphs are a specific arrangement of
piezoelectric layers that are stacked together
in a way that allows for enhanced or tailored
mechanical and electrical performance. They
are a type of multilayered piezoelectric
structure designed to optimize certain
characteristics for various applications.
Multimorph structure:

58. MULTIMORPHS:
a) A multimorph typically consists of
two or more piezoelectric layers
stacked together, often with each
layer having a different orientation
and polarization direction.
a) The layers are bonded
together in such a way that
when an electric field is
applied across the structure, it
induces bending or curvature
in the multimorph.

59. Working Principle:
Layered Configuration: A multimorph typically consists of two or more
piezoelectric layers that are stacked together. These layers can be made
of materials like PZT (lead zirconate titanate), PVDF (polyvinylidene
fluoride), or other piezoelectric materials. Each layer in the stack has a
different orientation and polarization direction.

60. a) Polarization and Orientation: The key to the functioning of multimorphs lies in the fact that
the individual layers have varying orientations and polarization directions. This means that
when an electric field is applied to the entire structure, each layer will respond differently
based on its orientation and the direction of the electric field.
a) Differential Expansion/Contraction: When the electric field is applied across the multimorph
structure, it induces an electric displacement in each layer. This displacement causes the
piezoelectric material to expand or contract along the direction of the electric field. However,
due to the differing orientations and polarization directions of the layers, they will expand or
contract by varying amounts.
a) Bending and Curvature: As a result of the differential expansion or contraction, the layers
will exert mechanical forces on each other. These forces will cause the multimorph to bend
or curve. The direction and magnitude of the bending are controllable and can be designed
to meet the specific requirements of the application.

61. a) Control of Bending: The bending characteristics of the multimorph can be controlled
and optimized by adjusting several parameters, including the thickness and material
properties of each layer, the orientation of the layers, and the magnitude of the applied
electric field. This allows for precise control over the shape and movement of the
multimorph.

62. a) Actuation and Sensing: Multimorphs can be used for actuation, where they provide controlled
mechanical movement, or for sensing, where they can detect mechanical forces or accelerations. The
bending of the multimorph can be harnessed for various applications, such as micro-positioning,
adaptive optics, energy harvesting, and more.
Applications:
a) Actuators: They are used to
create highly precise and
controllable actuators for
applications like micropositioning,
optical fiber alignment, and
adaptive optics.

63. a) Sensors: Multimorphs can be used as sensitive sensors for detecting mechanical forces or
accelerations.
b) Energy Harvesting: They are employed in energy harvesting devices to convert mechanical
vibrations or deformations into electrical energy.
a) MEMS (Micro-Electro-Mechanical Systems): In microscale devices, multimorphs can
provide precise mechanical movement for valves, mirrors, and other components.
Benefits:
a) Multimorph structures offer a way to achieve significant mechanical displacement or
deformation with relatively low voltage compared to single-layer piezoelectric devices.
a) They provide a high level of control over the direction and magnitude of bending or
curvature, making them valuable in applications requiring precise motion.
Multimorphs can be tailored to specific requirements by selecting appropriate piezoelectric
materials and layer configurations

64. ENVIRONMENTAL EFFECTS:
Linear Thermal Expansion
Thermal stability of piezoceramics is better than that of most other
materials. Actuators and positioning systems consist of a
combination of piezoceramics and other materials and their overall
behavior differs accordingly.
Temperature Dependency of the Piezo Effect
Piezo translators work in a wide temperature range. The piezo
effect in lead zirconate titanate (PZT) ceramics is known to function
down to almost zero kelvin, but the magnitude of the piezo
coefficients is temperature dependent.
At liquid helium temperature piezo gain drops to approximately 10–
20 % of its room temperature value.

65. ENVIRONMENTAL EFFECTS:
Piezoelectric sensors array based damage imaging method as a high resolution source
localization algorithm is becoming a promising method in structural health monitoring
(SHM) technology. However, the environmental variations could affect the gain-phase of
array signal. This paper experimentally evaluates the environmental effects on piezoelectric
sensors array, and presents a compensated 2D-MUSIC based damage imaging method for
composite structures
The polymer insulation materials used in piezoceramic actuators are sensitive to
humidity. Water molecules diffuse through the polymer layer and can cause short
circuiting of the piezoelectric layers. The insulation materials used in piezo actuators
are sensitive to humidity.

66. Thank You