A Comprehensive Guide to Actuator Types in IoT

Actuators are vital in Internet of Things (IoT) applications, transforming energy into motion or force to drive various automated tasks. From hydraulic systems in industrial machines to electrical actuators in smart home devices, each type serves a unique purpose. In this article, we will explore different actuator types, including hydraulic, pneumatic, electric, mechanical, magnetic, and soft actuators. Understanding their characteristics and applications can help identify the right actuator for specific IoT needs, enhancing efficiency and functionality across diverse fields.

What is an Actuator?

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.

• The component of a system (or machine) which moves or controls a mechanism or the system is called an actuator.
• An actuator requires a control signal and a source of energy.
• Upon receiving a control signal, the 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 the major functions or applications of different types of actuators in IoT systems.

Hydraulic Actuator

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

Pneumatic Actuator

• This actuator converts energy formed by vacuum or compressed air at high pressure into linear or rotary motion.

• They are responsible for converting pressure into force.

• Advantages:

  1. Pneumatic energy responds quickly to start and stop signals.
  2. It does require a 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 a motor which converts electrical energy into mechanical torque.
• Electrical energy is used to actuate equipment (e.g., solenoid valves) which control water flow in pipes in 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 the 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 a thermostat, magnetic actuator is an electromagnet

Soft Actuator

• It is polymer-based and designed to handle fragile objects like fruit harvesting in agriculture or manipulating internal organs in biomedicine.
• Examples: Shape Memory polymers, Photo polymers
• Shape memory polymer functions similarly to our muscles. It also provides a response to a 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 a special type of shape memory polymer that are activated by light stimuli.

Other Actuator Types

• 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 the automotive domain, they control various functions in vehicles, such as door locks, windows, and engine components.
• In the 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 equipment such as surgical robots and prosthetics.

Conclusion

Actuators play a crucial role in bridging the digital and physical worlds within IoT applications. Each type, such as hydraulic, pneumatic, electric, mechanical, magnetic, and soft, offers unique advantages tailored to specific requirements, from industrial automation to medical devices and smart homes. By selecting the right actuator, IoT systems can achieve higher accuracy, reliability, and efficiency. As IoT continues to advance, actuators will remain integral to innovative applications across sectors.