What are Actuators, its principle and applications

This article is about What are Actuators, its principle and applicationsand focusing to the engineers, technicians and supervisors. You will find lot of documents related to this article. Just navigate our website  www.paktechpoint.com  and find more articles. Please! Do not forget to subscribe our You tube channel also. Thanks in Advance.


What are Actuators, its principle and applications
  • Agent
  • Agent Requirements
  • Introduction to Actuators
  • Actuator Components
  • Actuator Types
  • Actuator Applications
  • Conclusion
  • Links & References
Actuators, its principle
An Agent
  • Perceives environment
  • Think for the results through their intelligence
  • Perform actions as a result


  • Human
  • Robot
  • Software
Intelligent Agent
An robot agent which works with its actuators and apparently, it works via sensors in environment.
Actuators, its principle


Agent Environment

Before we design an intelligent agent, we must specify its “task environment”:

  • Performance measure
  • Environment
  • Actuators
  • Sensors
Actuator stands for
A= Allowing
C= Component
T= To
U= Undergo
A= Action
T= To
O= Offer
R= Response
One that activates, a device responsible for actuating a mechanical device.
An actuator is the mechanism by which an agent acts as a result of any change perceived in the environment. The agent can be either an artificial intelligence agent or any other autonomous being (human, other animal, etc.
Actuators may be grouped in a number of ways: 
  • Electromechanical 
      1. Electromagnetic
      2. Electrodynamics
  • Fluid mechanical 
      1. Pneumatic
      2. Hydraulic 
  • Thermal

Electric Actuators

It uses ELECTRICAL energy for the activation function It may result in

    1. Rotation 
    2. Linear movement
    3. linear movement with gear or with real linear motor

Main Features

  • Easy to control
  • From mW to MW

Main Features

  • Normally high velocities 1000 – 10000 rpm
  • Several types
  • Accurate servo control
  • Ideal torque for driving
  • Excellent efficiency
  • Autonomous power system difficult
Principal of Operation

An electric current in a presence of magnetic field produces a force    F= I L X B    . . . (1)

thumbs ruleElectric Actuators



We make current carrying wire in form of loop, you can see two sides of loop perpendicular to the magnetic field and will experience forces with opposite direction


The pair of forces produce a turning effect or torque to move or rotate the coil
Electric Actuators
  • to produce a more uniform to torque, in pratical motor we should have more loops.
  • Electromagnets produce magnetic field and are called field coils 



Types of Motors

Following are some types of Motors:-

AC Motors
DC Motors

  • Modified from Basic AC DC Motors
    1. Torque Motors
    2. Servomotors
    3. Stepper Motors
    4. Brushless Motors
    5. Linear Motors
Types of Motors

Hydraulic Actuators

  • It uses HYDRAULIC head (of water) for the actuation function
  • Main Components
    1. Motor & pump actuator combination 
    2. Motor, generator, battery
    3. Motor & gear combination
  • Main Features
    1. Linear movement
    2. Larger forces without gears
Hydraulic Actuators

Main Features

    1. Actuators are simple
    2. In mobile machines
    3. Bad efficiency
    4. Many times larger load can be manipulated

Medium used

    1. Oil
    2. oil/water mix (non flammable)
  • water + corrosion inhibitors
    – virtually incompressible
    – viscosity heavily temperature dependent

Pressure Range

  • Up to about 30 MPa – 200 MPa for diesel injectors


  • Positioning with high load rigidity precision in closed loop control systems

Hydraulic Systems

Hydraulic Systems


Hydraulic Systems


Hydraulic Systems


Hydraulic Systems


Hydraulic Systems

Pneumatic Actuators

  •              Main Features                                               


  1.            Quick response
  2.            Large forces with elasticity
  3.            No leak problems
  •             Medium used 
  1.          Usually air 
– compressible
– separate lubrication probably required.
– viscosity fluctuations not important
Pressure Range
  1.          Up to about 1 MPa
  •      Applications
  •        Lower power and force / torque requirements,
  •        Positioning by mechanical stops in open loop systems.
Pneumatic Actuators


Pneumatic Actuators


Pneumatic Actuators


Pneumatic Actuators


Thermal Actuators

  • Working Principal
  1. Thermal Expansion
  • In bimetallic strip
  • In thermoloid material
Thermal Actuators










  •         When current is applied
  •         Thermoloid material, sealed in the actuator, changes phase from a solid to a     liquid and expands
  •        The volume of the Thermoloid material the material is essentially incompressible and encased in a rigid housing
  •          The piston moves and extends
  •          Motion occurs over a narrow temperature range
  1.              Merits
  •  precise control of a device at a specific temperature
  • operating temperature is extremely stable
  • repeatable and accurate
  1.          Applications
  • Temperature actuated valves
  • Switches & Latches
  • Clamps and control devices
  •  Instrument calibration

Piezoelectric Actuators

A device that cleverly harnesses piezoelectric property and produces movement is called a piezoelectric actuator.
High Power “Hard” Materials
High Sensitivity “Soft” Materials
Piezoelectric ActuatorsPiezoelectric Actuators


 Extremely rapid response of 0.01 milliseconds
Ultra-minute movements of 0.01 microns
Amazing power that exceeds 3 kilograms per square millimeter
The range of movement they can achieve is extremely limited, on the order of 0.05 millimeters.
Their various characteristics could only be applied to only a limited number of fields.
Optical Communications
Piezoelectric Actuators
-for Motor Vehicles
      -Mass flow controller
      -Semiconductor Equipment
      -Medical treatment.
Piezoelectric Actuators



You may also like...

1 Response

  1. August 7, 2018

    […] Please read also: What are Actuators, its principle and applications […]

Leave a Reply

%d bloggers like this: