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
Power
amplification
& modulation
Energy
conversion
Control
signal
Actuator
Output
Unmodulate
Energy source
Linear actuator: solenoid, Hydraulic/Pneumatic.
Rotary actuator: motor, Hydraulic/Pneumatic.
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.
Pneumatic valve.
Car door openers.
Hydraulic cylinder
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)
or jacks.
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
driving chambers.
Semi rotary actuators-
Produces non-continuous rotational motion.
Limited to less than one revolution (<360°).
Used to produce oscillatory motions in mechanisms.
Hydraulic jack.
Hydraulic brake.
Hydraulic ram.
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
10
Hydraulic & pneumatic actuators: cylindersHydraulic & pneumatic actuators: cylinders
Single acting:
work can be done only in one direction
Piston
Double acting piston:
Piston rod on both sides
Plunger
Work is done in both directions
Telescopic
Telescopic
Tandem
Non cushioned cylinders
are suitable for full stroke
working at slow speed.
Higher speeds with
external cushions.
12
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
actuator
Limited angle rotary
actuator
Parallel
piston
rotary
actuator
Mechanical linear actuators typically
operate by conversion of rotary
motion into linear motion.
Screw
Wheel and axle
Cam
Electrically actuated system are very widely used in control system
There are three types of motor used in control system
D.C. motor
A.C. motor
Stepper motor
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
A.C. motor
Stepper motor
Permanent magnet type
Variable reluctance type
Hybrid 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
titanade).
Advantages
short response time.
An ability to create high forces.
A high efficiency and a high mechanical durability.
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).
 A piezo ceramic crystal is coated with silver on both sides.
 Glued to a brass, nickel alloy, or stainless steel disk.
Brass:
Commercial & industrial use.(not subjected to environment )
Nickel alloy:
Use where it subjected to environment.
Stainless steel:
Uses where it subjected to solvent, corrosive chemical,
Underwater .
Medical fields.
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.
LED
LCD’s
Gas plasma display
CRT
Sirens/Horns - Sirens or horns can be useful for unattended or
dangerous machines to make conditions well known.
Actuators.ppt

Actuators.ppt

  • 2.
    Actuators are devicesused 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
  • 3.
  • 4.
    Linear actuator: solenoid,Hydraulic/Pneumatic. Rotary actuator: motor, Hydraulic/Pneumatic.
  • 5.
    A solenoid isa 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.
  • 6.
    Pneumatic valve. Car dooropeners. Hydraulic cylinder Single pressure line
  • 7.
    Hydraulic systems areused 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) or jacks. 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 driving chambers.
  • 8.
    Semi rotary actuators- Producesnon-continuous rotational motion. Limited to less than one revolution (<360°). Used to produce oscillatory motions in mechanisms. Hydraulic jack. Hydraulic brake. Hydraulic ram. Used as sensor. Close loop velocity controlling. Highly precise positioning for heavy loads.
  • 9.
    It convert energyformed by compressed air at high pressure into ether linear or rotary motion. Quickly respond in operation. Pneumatic actuatorPneumatic actuator
  • 10.
    10 Hydraulic & pneumaticactuators: cylindersHydraulic & pneumatic actuators: cylinders Single acting: work can be done only in one direction Piston Double acting piston: Piston rod on both sides Plunger Work is done in both directions Telescopic Telescopic Tandem
  • 11.
    Non cushioned cylinders aresuitable for full stroke working at slow speed. Higher speeds with external cushions.
  • 12.
    12 Rotary hydraulic actuatorsRotaryhydraulic 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 actuator Limited angle rotary actuator Parallel piston rotary actuator
  • 13.
    Mechanical linear actuatorstypically operate by conversion of rotary motion into linear motion. Screw Wheel and axle Cam
  • 14.
    Electrically actuated systemare very widely used in control system There are three types of motor used in control system D.C. motor A.C. motor Stepper motor 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
  • 15.
    A.C. motor Stepper motor Permanentmagnet type Variable reluctance type Hybrid type A stepper motor is an electromechanical device which converts electrical pulses into discrete mechanical movements.
  • 16.
    Pierre and JacquesCurie 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 short response time. An ability to create high forces. A high efficiency and a high mechanical durability. 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).
  • 17.
     A piezoceramic crystal is coated with silver on both sides.  Glued to a brass, nickel alloy, or stainless steel disk. Brass: Commercial & industrial use.(not subjected to environment ) Nickel alloy: Use where it subjected to environment. Stainless steel: Uses where it subjected to solvent, corrosive chemical, Underwater . Medical fields.
  • 18.
  • 19.
    Heaters - usedwith 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. LED LCD’s Gas plasma display CRT Sirens/Horns - Sirens or horns can be useful for unattended or dangerous machines to make conditions well known.