Actuators and its types in Internet of Things (IoT)

In the context of Internet of Things (IoT), actuators play a crucial role in enabling physical interaction and control of devices and systems. IoT actuators are used to convert digital signals or commands from the IoT network or cloud into physical actions. Some common types of actuators that power smart IoT devices and systems include electric, pneumatic, piezoelectric and soft actuators.

What is Actuator?

• The component of a system (or machine) which moves or controls mechanism or the system is called actuator.
• An actuator requires control signal and source of energy.
• Upon receiving control signal, actuator responds by converting energy into mechanical motion.
• The control system can be simple (fixed mechanical or electric system), software based (e.g. a printer driver, robot control system), a human or any other input.


Let us understand major functions or applications of different types of actuators.

Specific applications and Functions of Actuators

Let us understand functions and applications of actuator types.

Hydraulic actuator

• This actuator converts mechanical motion into linear, rotary or oscillatory motion.
• The hydraulic actuator consists of cylinder or fluid motor which uses hydraulic power to help mechanical operation.
• Liquids are nearly impossible to compress, hydraulic actuator maintains considerable force. Limited acceleration of actuator restricts its usage.
• Example: Hydraulic brake in vehicle

Pneumatic actuator

• This actuator converts energy formed by vacuum or compressed air at high pressure into linear or rotary motion.
• They are responsible to convert pressure into force.
• Advantages: 1. Pneumatic energy responds quickly to start and stop signals. 2. It does require power source to be stored in reserve for its operation. 3. Pneumatic actuators produce large forces from relatively small pressure changes.
• Examples:
➤Rack and Pinion actuators used for valve controls of pipes
➤Pneumatic brakes are very responsive to small pressure changes applied by the driver.

Electrical actuator

• It is powered by motor which converts electrical energy into mechanical torque.
• Electrical energy is used to actuate equipments (e.g. solenoid valves) which control water flow in pipes with response to electrical signals.
• Advantages: cheap, clean, speedy type of actuator.
• Examples: Solenoid based electric bell ringing mechanism

Mechanical actuator

• It converts rotary motion into linear motion.
• It consists of gears, pulleys, rails, chains and other devices for its operation.
• Examples: Rack and pinion mechanism and Crank shaft

Thermal or Magnetic actuator

• This actuator can be actuated by application of thermal or magnetic energy.
• This actuator uses shape memory materials e.g. shape memory alloys
• Advantages: Compact, light in weight, economical, offers high power density
• Examples: Thermal actuator is thermostat, magnetic actuator is electro magnet

Soft actuator

• It is polymer based and are designed to handle fragile objects like fruit harvesting in agriculture or manipulating the internal organs in biomedicine.
• Examples: Shape Memory polymers, Photo polymers
• Shape memory polymer is functions similar to our muscles. It also provides response to range of stimuli e.g. light, electrical, heat, magnetic, pH, moisture changes etc. The advantages of such polymers are low density, high strain recovery, bio-compatibility, bio-degradability etc.
• Photo polymers are known as light activated polymers. They are special type of shape memory polymers which are activated by light stimuli.

Other Actuator Types

Following are the other types of Actuators.
• Comb drive
• Electric motor
• Digital micromirror device
• Electroactive polymer
• Piezoelectric actuator
• Screw Jack
• Hydraulic Cylinder

Common applications of actuators

Following are the generic applications of actuators across various industries and technologies.
• In robotics, they are essential components in robot joints and limbs which allow them to move and interact with their environment.
• In automotive domain, they control various functions in vehicles, such as door locks, windows and engine components.
• In aerospace domain, they are used in aircraft control surfaces, landing gear and other systems.
• In industrial automation, they are used for precise control and positioning of machinery.
• They are used in HVAC systems to regulate temperature and airflow.
• Actuators are used in medical equipments such as surgical robots and prosthetics.

Conclusion: These types of actuators provide the physical functionality required for IoT devices to interact with the real world. They are integrated into IoT systems to enable remote and automated control, monitoring, and manipulation of devices and processes. They contribute to the advancement of smart and interconnected technologies. Soft actuators have become popular in IoT applications due to their unique capabilities and advantages which makes them suitable for specific tasks and environments.

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