An actuator is a device that converts energy into motion. Common types of actuators include pneumatic cylinders powered by compressed air and hydraulic cylinders powered by pressurized fluids. Actuators can produce either linear motion in a straight line or rotational motion. Examples of linear actuators are pneumatic cylinders, hydraulic cylinders, screw jacks, and ball screws. Rotary actuators include hydraulic motors. Actuators are widely used in manufacturing applications to move or position components. Common applications include robots, valves, pumps, and switches.
FRL UNIT
An FRL unit is comprised of a filter (F), regulator (R), and a lubricator (L).
The three components work together to do the following:
Filters remove water, dirt and other harmful debris from an air system. This is often the first step in improving the air quality.
Regulators adjust and control the air pressure of a system to ensure that down-line components do not exceed their maximum operating pressures. This is the second step in the FRL system.
Lubricators reduce the internal friction in tools or equipment by releasing a controlled mist of oil into the compressed air. This is often done last and/or right before the component needing lubrication.
FRL UNIT
An FRL unit is comprised of a filter (F), regulator (R), and a lubricator (L).
The three components work together to do the following:
Filters remove water, dirt and other harmful debris from an air system. This is often the first step in improving the air quality.
Regulators adjust and control the air pressure of a system to ensure that down-line components do not exceed their maximum operating pressures. This is the second step in the FRL system.
Lubricators reduce the internal friction in tools or equipment by releasing a controlled mist of oil into the compressed air. This is often done last and/or right before the component needing lubrication.
Hydraulic Valves and Hydraulic System AccessoriesRAHUL THAKER
Hydraulic Valves and Hydraulic System Accessories:
Direction control valves,Pressure control valves, Flow control valves, Non-return valves, Reservoirs,Accumulators, Heating & cooling devices, Hoses. Selection of valves for circuits.
Effect of non sinusoidal waveform of a.c. machine performancevishalgohel12195
Effect of Non sinusoidal waveform of A.C. Machine performance
Nonsinusoidal Waveforms
Key Similarities and Differences between Sinusoidal and Nonsinusoidal Waveforms
Effect of harmonics in motor drives
Square wave inverter with 180° mode
Effect of leakage reactance on the harmonic content of current
Parasitic torques due to non-sinusoidal voltages
Working elements of Pneumatic System with Circuits, Safety, InstallationMohammad Azam Khan
A pneumatic circuit is usually designed to implement the desired logics. However, there are several basics circuits, which can be integrated into the final circuit
raoid transverse and feed circut mostly used where two different speeds for operations are needed. example like punch and press, drill etc.
here the main components are reservoir tank, feed pump, one directional flow control valve, 2 DCV (3/2 & 4/3) and double acting cylinder.
Hydraulic Valves and Hydraulic System AccessoriesRAHUL THAKER
Hydraulic Valves and Hydraulic System Accessories:
Direction control valves,Pressure control valves, Flow control valves, Non-return valves, Reservoirs,Accumulators, Heating & cooling devices, Hoses. Selection of valves for circuits.
Effect of non sinusoidal waveform of a.c. machine performancevishalgohel12195
Effect of Non sinusoidal waveform of A.C. Machine performance
Nonsinusoidal Waveforms
Key Similarities and Differences between Sinusoidal and Nonsinusoidal Waveforms
Effect of harmonics in motor drives
Square wave inverter with 180° mode
Effect of leakage reactance on the harmonic content of current
Parasitic torques due to non-sinusoidal voltages
Working elements of Pneumatic System with Circuits, Safety, InstallationMohammad Azam Khan
A pneumatic circuit is usually designed to implement the desired logics. However, there are several basics circuits, which can be integrated into the final circuit
raoid transverse and feed circut mostly used where two different speeds for operations are needed. example like punch and press, drill etc.
here the main components are reservoir tank, feed pump, one directional flow control valve, 2 DCV (3/2 & 4/3) and double acting cylinder.
This project is on the design and construction of a solar power hacksaw machine for cutting of metal to different size and length with the help of solar hacksaw.
This CIM and automation laboratory manual covers the G-Codes and M-codes for CNC Turning and Milling operations. Some concepts of Robot programming are also introduced.
This presentation was prepared for a seminar. I have shared this with you. This is not related to curriculam. Please writre your criticisms to: hareeshang@gmail.com.
Assembly of screw jack, Computer Aided Machine Drawing (CAMD) of VTU Syllabus prepared by Hareesha N Gowda, Asst. Prof, Dayananda Sagar College of Engg, Blore. Please write to hareeshang@gmail.com for suggestions and criticisms.
A pneumatic control valve actuator converts energy (typically in the form of compressed air) into mechanical motion. The motion can be rotary or linear, depending on the type of actuator.
HYDRAULIC POWER GENERATING AND UTILIZING SYSTEMS
Introduction to fluid power system - Hydraulic fluids - functions, types, properties, selection and application.
POWER GENERATING ELEMENTS: Pumps, classification, working of different pumps such as Gear, Vane, Piston (axial and radial), pump performance or characteristics, pump selection factors- simple Problems.
POWER UTILIZING ELEMENTS: Fluid Power Actuators: Linear hydraulic actuators – Types and construction of hydraulic cylinders – Single acting, Double acting, special cylinders like tandem, Rodless, Telescopic, Cushioning mechanism.
Hydraulic Motors, types – Gear, Vane, Piston (axial and radial) – performance of motors.
Set Up Basic Hydraulics Circuits Eng.Muath N.BaniSalim .docxlesleyryder69361
Set Up Basic Hydraulics Circuits
Eng.Muath N.BaniSalim
[email protected] 1
2
What is fluid power ?
• Fluid power is the technology that deals with the
generation , control ,and transmission of power using
pressurized fluids. It can be said that fluid power is the
muscle that moves industry. This is because fluid power
is used to push , pull ,regulate or drive virtually all the
machines of modern industry.
• Fluid power is subdivided into hydraulics using a liquid
such as mineral oil or water, and pneumatics using a gas
such as air or other gases
3
4
On this hydraulic excavator,
not only all working
movements (linear drives)
but also the propulsion of
the vehicle (rotary drive)
are hydraulically powered. 5
6
7
https://www.youtube.com/watch?x-yt-
ts=1422327029&x-yt-
cl=84838260&feature=player_detailpage&v
=fcIitdkVr_A
Start from the 35th sec
8
https://www.youtube.com/watch?feature=pl
ayer_detailpage&x-yt-cl=84838260&x-yt-
ts=1422327029&v=W7v4gLFSQsY
9
http://www.youtube.com/watch?feature=pla
yer_detailpage&v=plh8xMpc44k
Advantages of fluid power
• 1-Ease and accuracy of control
• By the use of simple levers and push buttons, the operator of
a fluid power system can readily start , stop speed up or slow
down and position forces that provides any desired
horsepower with tolerance as precise as one ten- thousand of
an inch
10
Ref: fluid power with applications 4th edition,
Anthony esposito
• 2-Multiplication of force
• A fluid power system (without using cumbersome gears,
pulleys , and levers) can multiply forces simply and efficiently
from a fraction of an ounce to several to several hundreds
tons of output.
11
• 3-Constant force or torque
• Only fluid power systems are capable of providing constant
force or torque regardless of peed change. This is
accomplished whether the work output moves a few inches
per hours.
12
• 4-Simplicity ,safety, economy
• In general , fluid power systems use fewer moving parts than
comparable mechanical or electrical systems. Thus , they are
simpler to maintain and operate . This ,in turn, maximize
safety ,compactness, and reliability.
13
The available Power Source for the
mechanical machines (Actuators)
• 1- Diesel engines
• 2-Electical Drive
• 3-Pnumatic actuators
• 4-Hydrulic actuators
14
• The choice of using electric, hydraulic, or
pneumatic motion systems is a
fundamental decision that affects
performance, costs, maintainability,
safety, ease of use, flexibility, and
reliability the needs of the application
and the capabilities of the technology
must be carefully evaluated—and then
balanced with a cost-benefit analysis.
15
Small note before the comparison
• As systems, neither one is better than the other.
There is no "Better", only "More suitable for a
specific purpose." Car tyres are Pneumatic...
they're full of air. Air is compre.
Student information management system project report ii.pdfKamal Acharya
Our project explains about the student management. This project mainly explains the various actions related to student details. This project shows some ease in adding, editing and deleting the student details. It also provides a less time consuming process for viewing, adding, editing and deleting the marks of the students.
Automobile Management System Project Report.pdfKamal Acharya
The proposed project is developed to manage the automobile in the automobile dealer company. The main module in this project is login, automobile management, customer management, sales, complaints and reports. The first module is the login. The automobile showroom owner should login to the project for usage. The username and password are verified and if it is correct, next form opens. If the username and password are not correct, it shows the error message.
When a customer search for a automobile, if the automobile is available, they will be taken to a page that shows the details of the automobile including automobile name, automobile ID, quantity, price etc. “Automobile Management System” is useful for maintaining automobiles, customers effectively and hence helps for establishing good relation between customer and automobile organization. It contains various customized modules for effectively maintaining automobiles and stock information accurately and safely.
When the automobile is sold to the customer, stock will be reduced automatically. When a new purchase is made, stock will be increased automatically. While selecting automobiles for sale, the proposed software will automatically check for total number of available stock of that particular item, if the total stock of that particular item is less than 5, software will notify the user to purchase the particular item.
Also when the user tries to sale items which are not in stock, the system will prompt the user that the stock is not enough. Customers of this system can search for a automobile; can purchase a automobile easily by selecting fast. On the other hand the stock of automobiles can be maintained perfectly by the automobile shop manager overcoming the drawbacks of existing system.
Final project report on grocery store management system..pdfKamal Acharya
In today’s fast-changing business environment, it’s extremely important to be able to respond to client needs in the most effective and timely manner. If your customers wish to see your business online and have instant access to your products or services.
Online Grocery Store is an e-commerce website, which retails various grocery products. This project allows viewing various products available enables registered users to purchase desired products instantly using Paytm, UPI payment processor (Instant Pay) and also can place order by using Cash on Delivery (Pay Later) option. This project provides an easy access to Administrators and Managers to view orders placed using Pay Later and Instant Pay options.
In order to develop an e-commerce website, a number of Technologies must be studied and understood. These include multi-tiered architecture, server and client-side scripting techniques, implementation technologies, programming language (such as PHP, HTML, CSS, JavaScript) and MySQL relational databases. This is a project with the objective to develop a basic website where a consumer is provided with a shopping cart website and also to know about the technologies used to develop such a website.
This document will discuss each of the underlying technologies to create and implement an e- commerce website.
Saudi Arabia stands as a titan in the global energy landscape, renowned for its abundant oil and gas resources. It's the largest exporter of petroleum and holds some of the world's most significant reserves. Let's delve into the top 10 oil and gas projects shaping Saudi Arabia's energy future in 2024.
Event Management System Vb Net Project Report.pdfKamal Acharya
In present era, the scopes of information technology growing with a very fast .We do not see any are untouched from this industry. The scope of information technology has become wider includes: Business and industry. Household Business, Communication, Education, Entertainment, Science, Medicine, Engineering, Distance Learning, Weather Forecasting. Carrier Searching and so on.
My project named “Event Management System” is software that store and maintained all events coordinated in college. It also helpful to print related reports. My project will help to record the events coordinated by faculties with their Name, Event subject, date & details in an efficient & effective ways.
In my system we have to make a system by which a user can record all events coordinated by a particular faculty. In our proposed system some more featured are added which differs it from the existing system such as security.
Industrial Training at Shahjalal Fertilizer Company Limited (SFCL)MdTanvirMahtab2
This presentation is about the working procedure of Shahjalal Fertilizer Company Limited (SFCL). A Govt. owned Company of Bangladesh Chemical Industries Corporation under Ministry of Industries.
Hybrid optimization of pumped hydro system and solar- Engr. Abdul-Azeez.pdffxintegritypublishin
Advancements in technology unveil a myriad of electrical and electronic breakthroughs geared towards efficiently harnessing limited resources to meet human energy demands. The optimization of hybrid solar PV panels and pumped hydro energy supply systems plays a pivotal role in utilizing natural resources effectively. This initiative not only benefits humanity but also fosters environmental sustainability. The study investigated the design optimization of these hybrid systems, focusing on understanding solar radiation patterns, identifying geographical influences on solar radiation, formulating a mathematical model for system optimization, and determining the optimal configuration of PV panels and pumped hydro storage. Through a comparative analysis approach and eight weeks of data collection, the study addressed key research questions related to solar radiation patterns and optimal system design. The findings highlighted regions with heightened solar radiation levels, showcasing substantial potential for power generation and emphasizing the system's efficiency. Optimizing system design significantly boosted power generation, promoted renewable energy utilization, and enhanced energy storage capacity. The study underscored the benefits of optimizing hybrid solar PV panels and pumped hydro energy supply systems for sustainable energy usage. Optimizing the design of solar PV panels and pumped hydro energy supply systems as examined across diverse climatic conditions in a developing country, not only enhances power generation but also improves the integration of renewable energy sources and boosts energy storage capacities, particularly beneficial for less economically prosperous regions. Additionally, the study provides valuable insights for advancing energy research in economically viable areas. Recommendations included conducting site-specific assessments, utilizing advanced modeling tools, implementing regular maintenance protocols, and enhancing communication among system components.
Sachpazis:Terzaghi Bearing Capacity Estimation in simple terms with Calculati...Dr.Costas Sachpazis
Terzaghi's soil bearing capacity theory, developed by Karl Terzaghi, is a fundamental principle in geotechnical engineering used to determine the bearing capacity of shallow foundations. This theory provides a method to calculate the ultimate bearing capacity of soil, which is the maximum load per unit area that the soil can support without undergoing shear failure. The Calculation HTML Code included.
Forklift Classes Overview by Intella PartsIntella Parts
Discover the different forklift classes and their specific applications. Learn how to choose the right forklift for your needs to ensure safety, efficiency, and compliance in your operations.
For more technical information, visit our website https://intellaparts.com
Democratizing Fuzzing at Scale by Abhishek Aryaabh.arya
Presented at NUS: Fuzzing and Software Security Summer School 2024
This keynote talks about the democratization of fuzzing at scale, highlighting the collaboration between open source communities, academia, and industry to advance the field of fuzzing. It delves into the history of fuzzing, the development of scalable fuzzing platforms, and the empowerment of community-driven research. The talk will further discuss recent advancements leveraging AI/ML and offer insights into the future evolution of the fuzzing landscape.
Courier management system project report.pdfKamal Acharya
It is now-a-days very important for the people to send or receive articles like imported furniture, electronic items, gifts, business goods and the like. People depend vastly on different transport systems which mostly use the manual way of receiving and delivering the articles. There is no way to track the articles till they are received and there is no way to let the customer know what happened in transit, once he booked some articles. In such a situation, we need a system which completely computerizes the cargo activities including time to time tracking of the articles sent. This need is fulfilled by Courier Management System software which is online software for the cargo management people that enables them to receive the goods from a source and send them to a required destination and track their status from time to time.
1. Introduction
An actuator is a type of motor for moving or controlling a mechanism or
system. It is operated by a source of energy, usually in the form of an electric
current, hydraulic fluid pressure or pneumatic pressure, and converts that energy
into some kind of motion. An actuator is the mechanism by which an agent acts
upon an environment. The agent can be either an artificial intelligence agent or any
other autonomous being (human, other animal, etc.).
Perhaps the most common type of actuator is powered by air and is called a
pneumatic cylinder or air cylinder. This type of actuator is an air-tight cylinder,
typically made from metal, that uses the stored energy of compressed air to move a
piston when the air is released or uncompressed. These actuators are most
commonly used in manufacturing and assembly processes. Grippers, which are
used in robotics, use actuators that are driven by compressed air to work much like
human fingers.
Many actuators have more than one type of power source. Solenoid valves,
for example, can be powered by both air and electricity. Alternatively, a solenoid
can be powered by both hydraulics and electricity.
2. What is an actuator?
An actuator is something that converts energy into motion. It also can be
used to apply a force. An actuator typically is a mechanical device that takes
energy — usually energy that is created by air, electricity or liquid — and converts
it into some kind of motion. That motion can be in virtually any form, such as
blocking, clamping or ejecting. Actuators typically are used in manufacturing or
industrial applications and might be used in devices such as motors, pumps,
switches and valves.
Electrical signal can be low power or high power. In case of low power
signal, additional circuitry is required to drive the actuator otherwise it can be
driven directly.
Actuators output can be position or rate i. e.linear displacement or velocity.
Actuation can be from few microns to few meters.
3. Hydraulic actuator:
Hydraulic systems are used to control & transmit power.A pump driven by
prime mover (electric motor) creates flow of fluid.
An actuator is used to convert the energy of the fluid back into mechanical
power Amount of output power developed depends upon the flow rate, pressure
drop across the actuator & its overall efficiency.
TYPES OF ACTUATORS
Linear actuator (hydraulic cylinder)
-Provides motion in straight line
-Linear displacement depends on stroke length (length of actuator)
-Usually referred to as cylinders, rams (single acting cylinders) or jacks (cylinder
used for lifting)
Rotary actuators (Hydraulic motors)
-Produces continuous rotational motion
-Pump shaft is rotated to generate flow, a motor shaft is causedto rotate by fluid
being forced into the driving chambers
Semi rotary actuators
4. -Produces non-continuous rotational motion
-Limited to less than one revolution (<360°)
-Used to produce oscillatory motions in mechanisms
LINEAR HYDRAULIC ACTUATORS (CYLINDERS)Common Types
#Single acting cylinder
#Double acting cylinder
#Displacement cylinder
Special Types
1. Plunger or ram
2. Telescoping.
3. Cable
4. Diaphragm
5. Bellow
6. Tandem
7. Duplex
8. Rotary actuators
5. Pneumatic actuator
It convert energy formed by compressed air at high pressure into ether linear or rotary
motion.
The devices intended for transformation of potential and kinetic energy of the stream of
compressed gas in mechanical energy of the output link that can be, for example, a rod of the
piston, a shaft of the turbine or the case of the jet device is called pneumatic engines of the
automated actuator.
All pneumatic actuators can be subdivided into the following types:
• diaphragm pneumatic actuators.
• pneumatic power cylinders.
• gas-engine pneumatic actuators.
• turbine pneumatic actuators.
• jet-stream pneumatic actuators.
• pneumomuscles.
• combined pneumatic actuators.
Advantages and disadvantages of Pneumatic Actuators.
Advantages:
• Simplicity of realization relatively to small back and forth motions;
• Sophisticated transfer mechanisms are not required;
• Low cost;
• High speed of moving;
• ease at reversion movements;
• Tolerance to overloads, up to a full stop;
• High reliability of work;
• Explosion and fire safety;
• Ecological purity;
• Ability to accumulation and transportation.
Disadvantages:
• Compressibility of the air.
• Impossibility to receive uniform and constant speed of the working bodies movement.
• Difficulties in performance at slow speed.
• Limited conditions - use of compressed air is beneficial up to the definite values of pressure.
• Compressed air requires good preparation.
7. • Consists of cylinder (barrel), piston, piston-rod (ram) & inlet port at piston end or blank end
(other end is known as rod end).
• Cylinder is machined to high surface finish (honing).
• Fluid enters through inlet port into piston end or blank end –pressure build up-force generation
on piston-movement of piston –EXTENSION or FORWARD STROKE.
• RETRACTION or RETURN by compression spring or under the influence of gravity (only in
case of vertical mounting).
• Usage of seals –Piston seal (imparts clearance between piston & cylinder for clear movement),
Rod seal or End seal (prevention of leakage from cylinder), Bearing (supports piston rod) &
Wiper (prevention of dirt/dust entry into the cylinder).
•Drain hole helps in removing the leaked oil across piston seal.
•Widely used in hydraulic systems operations.
DOUBLE ACTING CYLINDER
8. • Produces linear motion in two directions.
• May be single rod ended or double rod ended.
• Piston is connected to smaller diameter piston rod.
• Fluid pressure acts on either side of piston alternatively.
• Both sides of piston has oil ports.
• Parts of double acting cylinder.
• Fluid enters through left port causing extension stroke while when it enters through right port
causes retraction stroke, for present case.
• For a given pressure double acting cylinder (single rod type) exerts greater force when
extending than when retracting.
CONSTRUCTIONAL FEATURES OF CYLINDER
• Five basic parts –Base cap & Bearing cap with port connections, a cylinder barrel, piston &
piston rod.
• End caps are secured to barrel through welding or threaded connection.
• Smooth inner surface of barrel (seamless drawn tube) to prevent wear & leakage.
• Pistons (separates high & low pressure zones) are usually made of cast iron or steel.
• Function of End seal, bearing & wiper seal.
9. DISPLACEMENT CYLINDER
• Produces motion in one direction.
• No piston. Need no precision machining.
• Consist of cylinder, rod & end cap with bearing.
• Rod end inside cylinder is provided with collar while other end is connected to load.
• Collar prevents ejection of rod under fluid pressure.
• Amount of fluid entering in cylinder equals rod displacement from cylinder hence the name
displacement cylinder.
• Maximum thrust exerted by the displacement cylinder is given by
Maximum thrust = Pressure X rod area.
• Extend speed of the rod is given by Rod speed =Flow rate of fluid entering cylinder /Area of
cylinder rod displacement.
TANDEM CYLINDER
• Also known as combination cylinder.
10. • Two separate pistons are mounted on same rod.
• Two double acting cylinders are connected in series.
• Suitable for higher force (2 cylinders –twice force) generation with smaller cylinders.
• High volume of oil is required to drive the cylinders.
TELESCOPIC CYLINDER
• Multiple cylinders mounted concentrically within one another.
• Suitable for longer strokes with shorter retraction.
• Operates on displacement principle.
• Stop rings limit the movement of each section.
• When the cylinder extends, all the sections move together until the outer section is prevented
from further extension by its stop ring.
• Remaining sections continue out-stroking until the second outermost section reaches the limit
of its stroke and so on until all sections are extended, the innermost one being last of all.
• For a given input flow rate, the speed of operation will increase in steps as each successive
section reaches the end of its stroke.
• For a specific pressure the load lifting capacity reduces for each successive section.
• Example : high lift fork truck, tilting of truck dump bodies telescopic.
11. COUSHIONED CYLINDER
• End caps (base cap) have to withstand shock loads (fluid pressure or from kinetic energy of the
moving parts) at extremes of piston travel
• Reduction of shock loads with the help of cushion valves build in end caps
• Exhaust fluid flow is unrestricted until plunger enters the cap.
• As plunger enters end cap port fluid experiences blockage, passes through deceleration valve
(adjustable needle valve) which in turn reduces speed & the end of travel impact.
• Deceleration valve is adjustable to allow the deceleration rate to be set.
• A check valve is included in the end cap to bypass the deceleration valve & give near full flow
as the cylinder extends.
12. Screw:
lead screw, screw jack, ball screw and roller screw actuators all operate on the principle
of the simple machine known as the screw. By rotating the actuator's nut, the screw shaft moves
in a line.
Wheel and axle:
Hoist, winch, rack and pinion, chain drive, belt drive, rigid chain and rigid belt actuators operate
on the principle of the wheel and axle. A rotating wheel moves a cable, rack, chain or belt to produce
linear motion. [1]
Cam:
Cam actuators function on a principle similar to that of the wedge, but provide relatively
limited travel. As a wheel-like cam rotates, its eccentric shape provides thrust at the base of a
shaft.
Electrical actuator
Electrically actuated system are very widely used in control system because easy
interface with control system which are also electric and because electricity is easily available
unlike fluid power which require pump and compressor .
The disadvantage of electric actuator’s
Electric equipment is more hazard than other system unless made intrinsically safe, in
which case it become expansive.
Electric actuator have a poor torque-speed characteristic at low speed.
13. Electric actuator are all basically rotary motion and complicated mechanism needed to
convert rotation into other form of motion.
There are three types of motor used in control system
D.C. motor
A.C. motor
Stepper motor
Working Principle of motor
Every motor works on the principle that when a current-carrying conductor is placed in a
magnetic field, it experiences a mechanical force.
Classification of Motors
14. AC Induction motor
Components:
Stator: It carries three phase winding and is fed from 3-phase supply.
Rotor: It carries winding which works as a secondary as in transformer.
AC Synchronous motor
Stator: It carries three phase winding and is fed from 3-phase supply.
Rotor: It carries permanent magnet poles that rotate exactly with same speed as that of the stator
magnetic field, hence the name synchronous motor.
15. It is not self starting.
Stepper motors
A stepper motor is an electromechanical device which converts electrical pulses into discrete
mechanical movements. The shaft or spindle of a stepper motor rotates in discrete step increments
when electrical command pulses are applied to it in the proper sequence.
Advantage:
The rotation angle of the motor is proportional to the input pulse.
The motor has full torque at standstill (if the windings are energized)
Precise positioning and repeatability of movement since good stepper motors have an
accuracy of 3 – 5% of a step and this error is non-cumulative from one step to the next.
Excellent response to starting/ stopping/reversing.
A wide range of rotational speeds can be realized as the speed is proportional to the
frequency of the input pulses.
Disadvantage:
16. Not easy to operate at extremely high speeds.
Types of stepper motor
Permanent magnet type
Variable reluctance type
Hybrid type
17. SOLENOIDS (Electric actuator)
Solenoids are the most common actuator components. The basic principle of operation
is there is a moving ferrous core (a piston) that will move inside wire coil as shown in Figure.
Normally the piston is held outside the coil by a spring. When a voltage is applied to the coil and
current flows, the coil builds up a magnetic field that attracts the piston and pulls it into the
center of the coil. The piston can be used to supply a linear force
Applications
Pneumatic valve.
Car door openers.
Solenoids controlled valves
The flow of fluids and air can be controlled with solenoid controlled valves. An
example of a solenoid controlled valve is shown in Figure. The solenoid is mounted on the side.
When actuated it will drive the central spool left. The top of the valve body has two ports that
will be connected to a device such as a hydraulic cylinder. The bottom of the valve body has a
single pressure line in the center with two exhausts to the side. In the top drawing the power
flows in through the center to the right hand cylinder port. The left hand cylinder port is allowed
to exit through an exhaust port. In the bottom drawing the solenoid is in a new position and the
pressure is now applied to the left hand port on the top, and the right hand port can exhaust. The
symbols to the left of the figure show the schematic equivalent of the actual valve positions.
Valves are also available that allow the valves to be blocked when unused.
18. Piezoelectric actuators (Electric actuator)
Pierre and Jacques Curie discovered the piezoelectric effect in 1880.
The application of an electric field to a piezoelectric crystal leads to a physical
deformation of the crystal.
Piezoelectric materials are: Quartz, Ceramics, PZT(lead zirconate titanade).
Advantages
An ability to create high forces.
A high efficiency and a high mechanical durability.
short response time.
Disadvantage
Have small strains. (0.1-.2%)
High supply voltage needed.(60-1000V)
Large hysteresis. (actuator doesn’t go back to exactly where it started).
19. Types of piezoelectric actuators
1.Piezoelectric Stack Actuator
Perhaps the easiest way to produce a linear motion by the piezoelectric effect is to use a
stack actuator, which is a multilayer construction: each stack is composed of several
piezoelectric layers, as depicted in Figure.
The required dimensions of the stack can be easily determined from the requirements of the
application in question. The height is determined in respect to the desired movement and the
cross–sectional area in respect to the desired force.
The main problem of the stack actuators is the relatively small strain (0,1 – 0,2 %) obtained.
The movement can be increased by using for example levers or hydraulic amplifiers. It is noticeable,
that in addition to the desired longitudinal movement some lateral movement typically also occurs.
Therefore, a guiding has to be used if only longitudinal motion is desired.
Figure illustrates the deviations from the straight-line accuracy.
2. Linear Motors
Since the strain of the piezoelectric ceramics is relatively small, displacement amplifiers
or hybrid structures are needed. There are many amplification techniques such as levers and
hydraulic systems, and piezoelectric motors.
20. In the lever systems, the amplification is achieved with lever arms which magnify the
displacement. The output force of the lever system is significantly smaller than the actuator force.
Hydraulic systems use generally a piston for the amplification. The Micro- and Nanosystems
Research Group has developed a hydraulic amplifier based on the use of bellows.
Figure: A schematic of the Figure: A 3D-CAD model of the
Piezo hydraulic actuator Piezo hydraulic actuator
The linear steppers include an inchworm motor, a stick and slip actuator, and an impact
drive motor. The ultrasonic motors can be divided into standing wave and traveling wave
ultrasonic motors. In this paper, the operating principles of the inchworm motor, the stick & slip
actuator and the traveling wave ultrasonic motor are described.
In inchworm motors, the linear movement is achieved by using three piezo elements.
The operation principle is illustrated in above Figure.
3. Piezoelectric Benders
Piezoelectric bending actuators (or piezoelectric cantilevers, or piezoelectric bimorphs)
bear a close resemblance to bimetallic benders. The application of an electric field across the two
layers of the bender result in one layer to expand, while the other contracts. The net result is a
curvature much greater than the length or thickness deformation of the individual layers. With a
piezoelectric bender, relatively high displacements can be achieved, but at the cost of force and
speed.
There are some benders that have only one piezoelectric layer on top of a metal layer
(unimorph), but generally there are two piezoelectric layers and no metal (bimorph).
21. This way, the displacement is doubled in comparison to a single layer version. If the
number of piezoelectric layers exceeds two, the bender is referred as a multilayer. With thinner
piezo layers, a smaller voltage is required to produce the same electric field strength, and
therefore, the benefit of the multilayer benders is their lower operating voltage.
Bimorph and multilayer benders can be built into one of the two types: a serial or parallel
bender. In a serial bender, there are two piezoelectric layers with an anti-parallel polarization
connected to each other, and two surface electrodes.
Other types of actuator:
Resistance heater
Cartridge heater and Band heater are used with temperature sensors and temperature
controller to control the temperature in automated molding equipment and in soldering
operation.
The resistive heating element 1 comprises a substrate
2 which serves as carrier material and which is substantially plate-shaped, e.g. of
graphite, and an electrically conducting layer
3 in the form of a, in the present embodiment, meandering conductor path
22. 4 (shown with dash-dotted lines) e.g. of pyrolytic carbon. An insulating layer
5, e.g. of pyrolytic boron nitride is disposed between the substrate 2 and the conducting
layer 3 forming the conductor path
6 for protecting the conductor path 4 from external effects which also consists e.g. of
pyrolytic boron nitride. The ends of the conductor path 4 connecting to an outer side of
the resistive heating element 1 serve as terminals.
7, 8 for applying an electric voltage.
Light
Lights are used on almost all machines to indicate the machine state and provide
feedback to the operator.
Display devices are also actuator.
LED
Whenever we needed bright display we use LED an LED array for displaying
number’s.
Gas plasma display
CRT
23. LCD
LCD is low power consuming.
It don’t generate light.
It control the transmission of light.
Sirens/Horns –
Sirens or horns can be useful for unattended or dangerous machines to make
conditions well known.