1.5. Actuator in embedded system23456
1.5.1. Definition
An actuator is an output device that converts electrical signals into physical movement or action
An actuator is an output device that converts electrical energy into mechanical motion or another physical action.
1.5.2. How an Actuator Works
Every sensor follows three basic steps:
- Receives a signal from the microcontroller.
- Converts electrical energy.
- Produces movement or action.
Example:
Arduino → Relay → Water Pump → Irrigation
1.5.3. Types of Actuators
1.5.3.1. Electrical Actuators
Operate using electricity.
Example:
- DC Motor
- Servo Motor
- Stepper Motor
- Solenoid
1.5.3.2. Hydraulic Actuators
Use pressurized liquid.
Applications of hydraulic actuators
- Excavators
- Hydraulic lifts
- Industrial presses
Advantages of hydraulic actuators
- Produce high force.
1.5.3.3. Pneumatic Actuators
Use compressed air.
Applications of pneumatic actuators
- Factory automation
- Packaging machines
- Pneumatic valves
Advantages of pneumatic actuators
- Fast operation
- Clean.
- Safe in hazardous environments
1.5.3.4. Magnetic Actuators
A magnetic actuator is a device that converts electrical energy into mechanical motion using magnetic fields.
Electrical Energy → Magnetic Field → Mechanical Motion
When electric current flows through a coil, it creates a magnetic field. The magnetic field attracts or repels magnetic materials, producing motion.
Types of Magnetic Actuators
a) Solenoid
A solenoid consists of a coil and a movable iron core (plunger). When current flows through the coil, the plunger moves linearly.
Applications
- Door locks
- Automatic valves
- Fuel injectors
- Vending machines
b) Electromagnet
An electromagnet produces a magnetic field only when electric current flows.
Applications
- Scrap metal lifting cranes
- Magnetic door locks
- Industrial automation
- Electromagnetic relays
c) Electric Motor
Electric motors use magnetic fields to produce rotational motion.
Types Electric motors
- DC Motor
- AC Motor
- Brushless DC (BLDC) Motor
- Stepper Motor
- Servo Motor
Applications of Electric motors
- Fans
- Robots
- Electric vehicles
- Pumps
- Conveyor belts
1.5.3.5. Thermal Actuators Actuators
A thermal actuator is a device that converts electrical energy into heat or uses heat to produce mechanical movement.
Electrical Energy → Heat → Mechanical Motion or Temperature Change
When an electric current passes through a heating element or special material, heat is generated.
Types of Thermal Actuators
a) Heating Element
A heating element converts electrical energy directly into heat.
Applications
- Electric ovens
- Water heaters
- Electric irons
- Incubators
- 3D printer hot ends
b) Bimetallic Actuator
A bimetallic actuator consists of two different metals bonded together. Since the metals expand at different rates when heated, the strip bends and produces mechanical movement.
Applications
- Thermostats
- Circuit breakers
- Temperature switches
- Automatic electric kettles
c) Shape Memory Alloy (SMA) Actuator
A Shape Memory Alloy (such as Nitinol) changes shape when heated and returns to its original shape upon cooling.
Applications of Shape Memory Alloy (SMA) Actuator
- Medical devices
- Robotic grippers
- Aircraft control systems
- Micro-actuators
Advantages of Shape Memory Alloy (SMA) Actuator
- Simple construction
- Quiet operation
- High reliability
- Low maintenance
1.5.5. Characteristics of Actuators
A good actuator should have:
- High efficiency
- Fast response
- High reliability
- Accurate positioning
- Low maintenance
- Long service life
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