Actuators are devices used to produce action or motion.
Input(mainly electrical signal , air, fluids)
Electrical signal can be low power or high power.
Actuators output can be position or rate i. e.
linear displacement or velocity.
Actuation can be from few microns to few meters
A solenoid is a coil wound into a tightly packed helix.
In physics, the term solenoid refers to a long, thin loop
of wire, and wrapped around a metallic core.
which produces a magnetic field when an electric current
is passed through it.
Car door openers.
Single pressure line
Hydraulic systems are used to control & transmit power.
A pump driven by prime mover (electric motor) creates flow of fluid
Linear actuator (hydraulic cylinder)-
Provides motion in straight line.
Linear displacement depends on stroke length.
Usually referred to as cylinders, rams (single acting cylinders)
Rotary actuators (Hydraulic motors)-
Produces continuous rotational motion.
Pump shaft is rotated to generate flow.
A motor shaft is caused to rotate by fluid being forced into the
Semi rotary actuators-
Produces non-continuous rotational motion.
Limited to less than one revolution (<360°).
Used to produce oscillatory motions in mechanisms.
Used as sensor.
Close loop velocity controlling.
Highly precise positioning for heavy loads.
It convert energy formed by compressed air at high pressure
into ether linear or rotary motion.
Quickly respond in operation.
Pneumatic actuatorPneumatic actuator
Hydraulic & pneumatic actuators: cylindersHydraulic & pneumatic actuators: cylinders
work can be done only in one direction
Double acting piston:
Piston rod on both sides
Work is done in both directions
Non cushioned cylinders
are suitable for full stroke
working at slow speed.
Higher speeds with
Rotary hydraulic actuatorsRotary hydraulic actuators
Vane rotary actuator:
Limited angle in both directions.
Maximum angle always smaller than 360°
The same torque in both directions.
Piston rotary actuator:
With rack and gear coupling.
Here maximum angle may be larger than 360°
Limited angle rotary
Limited angle rotary
Mechanical linear actuators typically
operate by conversion of rotary
motion into linear motion.
Wheel and axle
Electrically actuated system are very widely used in control system
There are three types of motor used in control system
Every motor works on the principle that when a current-carrying
conductor is placed in a magnetic field, it experiences a mechanical force.
Working Principle of motor
Permanent magnet type
Variable reluctance type
A stepper motor is an electromechanical device which converts electrical pulses
into discrete mechanical movements.
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
short response time.
An ability to create high forces.
A high efficiency and a high mechanical durability.
Have small strains. (0.1-.2%)
High supply voltage needed.(60-1000V)
Large hysteresis.(actuator doesn’t go back to exactly
where it started).
A piezo ceramic crystal is coated with silver on both sides.
Glued to a brass, nickel alloy, or stainless steel disk.
Commercial & industrial use.(not subjected to environment )
Use where it subjected to environment.
Uses where it subjected to solvent, corrosive chemical,
Piezoelectric Stack Actuators
Produce linear motion.
Heaters - used with temperature sensors And temperature controller
to control the temperature in automated moulding
Equipment and in soldering operation.
Lights - Lights are used on almost all machines to indicate the
machine state and provide feedback to the operator.
Gas plasma display
Sirens/Horns - Sirens or horns can be useful for unattended or
dangerous machines to make conditions well known.