Actuators are essential components in the Internet of Things (IoT) ecosystem. They are the mechanisms that convert various forms of energy into motion, allowing IoT devices to physically interact with the environment.
There are several different types of actuators used in IoT applications, each with their own set of capabilities and use cases. In this article, we will explore the 9 major categories of actuators that empower connected devices to sense inputs and activate outputs in the physical world.
Overview of Actuators in IoT
Before diving into the different kinds of actuators, let‘s first understand what exactly actuators are and why they matter in IoT systems.
Actuators are the components that produce physical motion and force based on electronic control signals. They take energy, such as electrical, pneumatic or hydraulic power, and convert it into rotational movement or linear displacement.
In IoT ecosystems, actuators serve as the interface between digital systems and physical processes. They allow IoT devices to manipulate objects, move parts, control industrial machinery, and more based on sensor inputs and automated logic.
Without actuators, IoT devices would only be able to passively collect data about the external environment. Actuators enable them to act on the physical world and make things happen through movement.
Now let‘s explore the major categories of actuators that serve various functions across different IoT applications.
1. Electric Motors
Electric motors are one of the most widely used types of actuators in IoT and automation systems. They work by converting electrical energy into mechanical rotation using electromagnetic induction.
IoT applications employ various kinds of electric motors – AC motors, DC motors, stepper motors, servo motors and more. Each type has its own torque, speed and control capabilities suitable for different use cases.
How Electric Motors Work
The basic principle behind any electric motor is electromagnetic induction between coils carrying current and magnetic fields surrounding them. By changing the polarity and strength of energized coils in a sequence, a rotational force is generated.
Parts of an electric motor:
- Stator – The static part containing permanent magnets or electromagnets
- Rotor – The rotating part powered by the rotating magnetic field
- Commutator – Allows DC current direction to switch in sync with rotor movement
- Brushes – Transfers power from external source to the spinning rotor
Applications of Electric Motors in IoT
Electric motors supply mechanical power for movement and motion in numerous IoT applications:
- Industrial Robotics – Multi-axis robotic arms and automated machinery used in Industry 4.0 manufacturing facilities.
- Transportation – Wheeled robots, autonomous vehicles, delivery drones.
- Smart Home Devices – Motorized windows, vacuum cleaners, garage door openers.
- Precision Equipment – Stepper motors in 3D printers, CNC machines, surgical tools.
Overall, the versatility, precision control and high power density make electric motors suitable for most IoT applications that involve physical motion.
2. Servo Motors
Servo motors are a specialized type of actuators designed for precise position control applications. In contrast to regular motors which provide just torque and speed, servo motors use closed-loop control circuits to achieve accurate orientation and placement.
This makes them ideal for IoT systems that demand repetitive motions and synchronized components like robotics, radars and assembly lines.
How Servo Motors Work
Servo motors contain an in-built feedback circuit that lets external controllers monitor and adjust position in real time. This circuit consists of:
- Control circuitry to command intended positions
- Potentiometer/encoder to track actual position
- Error-correction signals to reach and sustain right orientation
Based on live sensing of position, the servo recalibrates rotation quickly and accurately. This enables exceptional responsiveness and precision compared to open-loop motors.
IoT Applications of Servo Motors
Here are some common examples of servo motors in IoT ecosystems:
- Robotics – Multi-axis arms, self-driving cars, humanoid robots
- Industrial Automation – Pick-and-place machines, CNC routers, conveyors
- Surveillance Systems – Pan-tilt camera rotation mechanisms
- Automotive – Power-assisted steering, automatic braking systems
- Avionics – Flight control and stabilization equipment
With closed-loop speed and position control functionalities, servo motors facilitate accuracy and synchronization in motion-critical IoT systems.
3. Solenoids
Solenoids are electro-mechanical actuators that produce linear actuation for unlocking, releasing or triggering physical mechanisms. They consist of a helical coil of wire wrapped around a movable metallic plunger or piston.
When current is passed through the coil, it becomes magnetized and creates a linear force that pulls/pushes the plunger in a straight line. This linear actuation makes them ideal for electronic locking systems and mechanical controls which need simple on/off movements.
How Solenoids Work
The working principle relies on the linear force between the induced electromagnetic field of the coil and the plunger which serves as its armature.
By attracting the plunger into the center of the coil when energized, solenoids can provide straight-line thrust and impact to unlock latches, depress levers or strike components.
This linear actuation mechanism gives solenoids toggle-type control capabilities for a huge range of applications.
IoT Applications of Solenoids
Here are some common examples where solenoid linear actuators serve important functions in IoT ecosystems:
- Door Locks & Access Control – Electronic locks, deadbolts, vehicle locking
- Valves & Fluid Control – Irrigation systems, additive manufacturing
- Switching & Impact Mechanisms – Circuit breakers, robotic strikers
- Vending Machines – Product release traps, acceptance checks
- Automotive Systems – Door locks, brake fluid valves, horn triggers
With simple yet reliable linear motion generation, solenoids enable on/off actuation for critical mechanisms across IoT systems.
4. Stepper Motors
Stepper motors are digital actuators that move in discrete steps allowing for precise position control without any feedback sensor. This stepping motion lets them excel in applications needing high accuracy like 3D printing and CNC machining.
Their ability to translate input pulses into proportional shaft rotation makes stepper motors ideal for open-loop position control applications.
How Stepper Motors Work
Stepper motors consist of multiple toothed electromagnets arranged radially around a central gear. By energizing the electromagnets in an orchestrated sequence, they magnetically pull the gear causing it to rotate step-by-step.
Key Components:
- Stator – Multi-toothed electromagnets
- Rotor – Central geared shaft
- Driver – Converts digital pulses into stator energizing sequences
By controlling pulse frequency and sequences sent to the driver, rotational speed and position can be finely regulated.
IoT Applications of Stepper Motors
With their intrinsic stepping action and control precision, stepper motors are widely adopted across IoT ecosystems including:
- 3D Printing & CNC Machining – High precision linear and rotary motion
- Robotics – Wheeled robot locomotion, multi-axis arms
- Automation Equipment – Conveyors, pick-and-place machines
- Healthcare – Drug infusion pumps, ventilators
- Wearable Technology – Step counters, exoskeletons
Stepper motors lend digital accuracy to motion control for equipment that depend on reliability, speed and cost-effectiveness.
5. Linear Actuators
As their name suggests, linear actuators are designed to produce linear motion or straight-line movement. They come in electric, hydraulic or pneumatic variants and provide reciprocating thrust to push, pull or lift loads.
With customizable force and stroke lengths, linear actuators serve numerous automation tasks involving doors, axes, linkages that need back-and-forth action.
How Linear Actuators Work
While underlying technologies differ, all linear actuators work on the principle of converting rotary motion of motors or fluids into linear movement through mechanical conversion components:
- Electric – Lead screws or belts powered by motors
- Hydraulic – Fluid pressure fed into output cylinder
- Pneumatic – Compressed air pushed into extensible chamber
This reciprocating linear motion allows them to automate sliding, opening/closing and pick-and-place mechanisms.
IoT Applications of Linear Actuators
Linear actuation capacities make these actuators suitable for:
- Industrial Robotics – Cartesian robots, rod linkage systems
- Automation Equipment – Conveyors, assembly line part feeders
- Domotics – Motorized doors, windows, furniture
- Automotive – Convertible car roofs, automatic tailgates
- Healthcare – Patient lifting systems, adjustable beds
With versatile speed and force scalability, linear actuators provide reliable automation of sliding and lifting tasks across IoT ecosystems.
6. Pneumatic Actuators
Pneumatic actuators produce motive power by harnessing compressed gases – usually air. They offer high speed, reliability and cost-effectiveness for automation tasks not needing the complexity of motors and gears.
Pneumatics function via compressed air fed into chambers with output rods or vanes. By controlling air pressure, force and extension of these rods can be regulated.
How Pneumatic Actuators Work
Pneumatic systems comprise an air compressor, distribution system (valves and tubes) and air-powered cylinders/engines.
Pressurized air has potential mechanical energy that can reciprocate pistons or rotate rotors to generate motion. This clean movement makes them suitable for food & healthcare applications too.
IoT Applications of Pneumatic Actuators
Pneumatic actuation facilitates specialized tasks across IoT verticals:
- Industrial Automation – Assembly robots, automatic product testing rigs, pick-and-place machines
- Transportation – Truck braking systems, vehicle suspension
- Avionics – Aircraft flight control systems, engine starters
- Biomedical – Anesthesia delivery systems, respirators, medical air pumps
With efficient power-to-weight ratio and design flexibility, pneumatic actuators complement electric options for low-complexity fluid-based automation.
7. Hydraulic Actuators
Hydraulic actuators operate on the principle of fluid power transmission using pressurized liquid. Most hydraulic systems use oil as the working fluid which is pumped into cylinders to create linear or rotary motion.
Generating extremely high forces from small actuators, hydraulics are ideal for heavy lifting and earth moving equipment. They also facilitate smooth control of weighty components.
How Hydraulic Actuators Work
Hydraulic systems comprise a reservoir, pump, valves and cylinder/motor pair. The pump presses oil from the reservoir into the cylinder forcing its piston to extend/retract.
Control valves regulate fluid pressure and flow direction. By managing this system, huge unidirectional forces can be produced to operate heavy mechanisms.
IoT Applications of Hydraulic Actuators
The extreme power density hydraulic actuators provide is leveraged across IoT verticals:
- Construction & Agriculture – Backhoes, bulldozers, tractors, robotic arms
- Aerospace – Flight control, wheel brakes and flap actuators
- Industrial – Presses, jacks, lifts, conveyors, submarine tooling
- Renewable Energy – Tidal turbines, wave energy harvesting buoys
With strength multiplication and flow control competencies, hydraulics serve demanding tasks in the harshest IoT application environments.
8. Piezoelectric Actuators
Piezoelectric actuators produce precise linear displacement on the order of microns using unique electromechanical properties of certain crystals. Under applied voltage, these crystals undergo atomic deformations creating tiny motions usable across micropositioning systems.
With low power needs and lightning-quick response times, piezoelectric actuators assume critical roles in high-precision optics, acoustics and robotics equipment.
How Piezoelectric Actuators Work
Piezoelectricity is caused due to asymmetrical crystal lattice structures possessing electric dipoles. When subjected to electric stimulus, one set of dipoles elongates while the other contracts.
This atomic strain cumulatively leads to measurable macroscopic displacement that can be utilized for microactuation.
IoT Applications of Piezoelectric Actuators
The nano-scale motions from piezoelectricity facilitate ultra-fine control across:
- Microscopy – Atomic force, scanning tunneling and optical microscopes
- Printing – Inkjet printers, micropipettes
- Optics – Adaptive optics, auto-focus, stabilization
- Acoustics – Ultrasonic transducers, speakers
- Haptics & Telepresence – Tactile feedback, vibration control
Thus, piezoelectric actuators constitute an entire domain of micro-actuators vital for precision tasks in IoT ecosystems.
9. Shape Memory Alloys
Shape memory alloys (SMA) are remarkable smart materials that can return to their original shape when heated beyond a transformation temperature. After apparent plastic deformation, they instantly snap back upon heating.
This unique property known as the shape memory effect generates usable strokes making them novel linear actuators.
How Shape Memory Alloys Work
SMAs like nickel-titanium alloys (nitinol) can exist in two solid state crystal phases – low temperature martensite (malleable) and high temperature austenite (rigid).
Heating triggers an atomic rearrangement from twisted martensite to ordered austenite, forcing the alloy to recall its previous high-temp shape. This phase change releases large recovery forces usable for actuation.
IoT Applications of Shape Memory Alloys
The solid-state actuation of SMAs is advantageous across:
- Biomedical – Catheters, stents, orthodontic wires, orthopedic fixation
- Aerospace – Satellite antenna and solar array deployment
- Automotive – Comfort and safety – electric valves
- Industrial – Fire protection valves, adaptive structures
- Robotics – Continuum manipulators inspired by elephant trunks
With bio-inspired complex motion capabilities, SMA morphing actuators open new possibilities for smart IoT systems.
And those are 9 major types of actuators empowering the growing multitude of IoT applications through their unique motion generation competencies! Understanding their fundamental traits and use cases provides great perspective into theInner Workings of the Internet of Things. This knowledge serves well while designing, selecting and interfacing appropriate actuators to physical tasks across IoT ecosystems.
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