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Monday, 18 March 2019

Actuator in IoT

An actuator is a component of a machine or system  that moves or controls the mechanism or the system.

An actuator is the mechanism by which a control system acts upon an environment

An actuator requires a control signal and a source of energy.

Upon receiving a control signal, the actuator tor responds by converting the energy into mechanical motion.

The control system  can be simple (a fixed mechanical or electronic system), software-based (e.g. a printer driver, robot control system), a human, or any other input.



Actuator Types
  • Hydraulic
  • Pneumatic
  • Electrical
  • Thermal/Magnetic
  • Mechanical
Hydraulic Actuators 
  • A hydraulic actuator consists of a cylinder or fluid motor that uses hydraulic power to facilitate mechanical operation.
  • The mechanical motion is converted to linear, rotary or oscillatory motion.
  • Since liquids are nearly impossible to compress, a hydraulic actuator exerts considerable force.
  • The actuator's limited acceleration restricts its usage.



Pneumatic Actuators :
  • A pneumatic actuator converts energy formed by vacuum or compressed air at high pressure into either linear or rotary motion.
  • Pneumatic rack and pinion actuators are used for valve controls of water pipes.
  • Pneumatic energy quickly responds to starting and stopping signals.
  • The power source does not need to be stored in reserve for operation.
  • Pneumatic actuators enable large forces to be produced from relatively small presure changes (e.g., Pneumatic brakes can are very responsive to small changes in pressure applied by the driver).
  • It is responsible for converting pressure into force.



Electric Actuators
  • An electric actuator is generally powered by a motor that converts electrical energy into mechanical torque.
  • The electrical energy is used to actuate equipment such as solenoid valves which control the flow of water in pipes in response to electrical signals.
  • Considered as one of the cheapest, cleanest and speedy actuator types available.



Thermal or Magnetic Actuators
  • These can be actuated by applying thermal or magnetic energy.
  • They tend to be compact, lightweight, economical and with high power density.
  • These actuators use shape memory materials (SMMs), such as shape memory alloys (SMAs) or magnetic shape-memory alloys (MSMAs).
  • Some popular manufacturers or these devices are Finnish Modti Inc. and American Dynalloy.

Mechanical Actuators
  • A mechanical actuator converts rotary motion into linear motion to execute some movement.
  • It involves gears, rails, pulleys, chains and other devices to operate.
  • Example : rack and pinion


Soft Actuators
  • Soft actuators (e.g. polymer based) are designed to handle fragile objects like fruit harvesting in agriculture or manipulating the internal organs in biomedicine.
  • They typically address challenging tasks in robotics.
  • Soft actuators produce flexible motion due to the integration of microscopic changes at the molecular level into a macroscopic deformation of the actuator materials.

Shape Memory Polymers
  • Shape memory (SMP) actuators function similar to our muscles, even providing a response to a range of stimuli such as light, electrical, magnetic, heat, PH, and moisture changes.
  • SMP exhibits surprising features such a low density, high strain recovery, biocompatibility, and biodegradability.
Light Activated Polymers
  • Photopolymer/light activated polymers (LAP) are a special type of SMP that are activated by light stimuli.
  • The LAP actuators have instant response.
  • They can be controlled remotely without any physical contact, only using the variation of light frequency or intensity.


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