What is an Actuator?
An actuator is a device that produces motion—either linear or rotary—by converting energy into mechanical force. Actuators are fundamental components in automation, robotics, manufacturing, automotive systems, and even in everyday items like electric recliners or car door locks.
At its core, an actuator takes energy (usually electrical, hydraulic, or pneumatic) and uses it to move or control a mechanism or system. Think of actuators as the muscles of machines, responsible for physical movement.
Types of Actuators
Actuators are broadly categorized into two types based on the motion they produce:
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Linear Actuators – produce motion in a straight line.
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Rotary Actuators – produce rotational motion.
We’ll explore each type and their subcategories below.
Linear Actuators
1. Electric Linear Actuators
These actuators use an electric motor to drive a lead screw or similar mechanism to create linear motion. The length of travel, called "Stroke" can range from 0.1mm to around 60" and speeds can go from very low to as high as about 4" per second typically. Forces for electric linear actuators typically top out at around 2,000 lbs force, to go greater you have to go Hydraulically powered.
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Applications: Home automation, adjustable beds, industrial machinery, robotics, home automation, farming, boating.
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Firgelli Products: Electric Linear Actuators
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Pros: low to medium force output. very precise positional control possible, large range of forces and stroke options.
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Cons: Max force is around 2,000 lbs n
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Diagram of an Electric Linear Actuator showing motor, lead screw, slider, and housing.
2. Hydraulic Linear Actuators
These use pressurized hydraulic fluid to push a piston inside a cylinder, generating strong linear motion. Typically Hydrailuc actuators are slower than electric, however they can push massive forces.
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Applications: Heavy machinery, construction equipment, aircraft control systems.
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Pros: High force output.
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Cons: Requires pumps, fluid maintenance, prone to leaks.
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Diagram of a Hydraulic Linear Actuator showing piston, cylinder, and fluid input.
3. Pneumatic Linear Actuators
Similar to hydraulic actuators but use compressed air instead of fluid. These can go extremely fast, but have very little control over them because they require compressed air which expands and contracts giving you little to no positional control. These are ideal for simple end to end motion control applications
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Applications: Manufacturing automation, packaging, material handling.
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Pros: Fast, clean.
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Cons: Lower force, less precise, no positional control.
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Diagram of a Pneumatic Linear Actuator showing air inlet, piston, and housing.
4. Piezoelectric Actuators
Use piezoelectric materials that deform when voltage is applied, producing very small but precise movements.
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Applications: Precision instruments, medical devices, micro-positioning.
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Pros: Extremely precise, no moving parts.
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Cons: Very limited stroke length.
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Diagram of a Piezoelectric Actuator showing piezo stack, voltage input, and displacement direction.
Rotary Actuators
1. Electric Rotary Actuators
These convert electrical energy into rotational motion using a motor and gearing system.
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Applications: Robotics joints, camera gimbals, industrial automation.
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Firgelli Products: Electric Rotary Actuators
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Diagram of an Electric Rotary Actuator showing motor, geartrain, and output shaft.
2. Hydraulic Rotary Actuators
Use hydraulic pressure to generate torque and rotation, often using a vane or piston mechanism.
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Applications: Construction vehicles, marine equipment, heavy lifting arms.
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Diagram of a Hydraulic Rotary Actuator showing vane, rotor, and fluid channels.
3. Pneumatic Rotary Actuators
Use compressed air to generate rotation through vanes or pistons inside a chamber.
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Applications: Valve control, pick-and-place machines, automation systems.
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Diagram of a Pneumatic Rotary Actuator showing vane chamber and air inlet.
Comparison Table: Actuator Types
| Actuator Type | Motion | Energy Source | Strength | Precision | Speed | Maintenance | Cost |
|---|---|---|---|---|---|---|---|
| Electric Linear | Linear | Electric | Medium | High | Medium | Low | Medium |
| Hydraulic Linear | Linear | Hydraulic | Very High | Medium | Low | High | High |
| Pneumatic Linear | Linear | Air | Medium | Low | High | Medium | Low |
| Piezoelectric | Linear | Electric | Low | Very High | Low | Very Low | High |
| Electric Rotary | Rotary | Electric | Medium | High | Medium | Low | Medium |
| Hydraulic Rotary | Rotary | Hydraulic | Very High | Medium | Low | High | High |
| Pneumatic Rotary | Rotary | Air | Medium | Low | High | Medium | Low |
Conclusion
Actuators are essential components in countless modern technologies, powering everything from massive construction equipment to delicate surgical instruments. Choosing the right actuator depends on your application’s requirements—force, speed, precision, environment, and cost.
For more details on selecting the right actuator, check out these Firgelli blog posts:
Explore our full range of actuators:
