What is an Actuator?


An actuator is the part of a machine or device which helps it achieve mobility by transforming energy (mostly electric, air, or hydraulic) into mechanical power. In other words, it's the part in almost any machine that allows movement.

Actuator exploded view

It may be compared to the operation of your body. Like muscles within a body that power movement of legs or arms, actuators operate in a system to execute a mechanical action.

Actuators exist in virtually every machine around us, from easy digital control systems to the vibrator in our cell phone.  You will find them in household appliances, vehicles, industrial apparatus, robots and countless other things.

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What is a Linear Actuator?

A linear actuator is a tool that transforms rotational motion into linear motion - straight up and down movement.  Depending on the function of the actuator, this movement can be powered by electric, hydraulic, or pneumatic energy.  Electric and piezoelectric actuators, for example, operate on the input of electrical voltage or current supplied by DC or AC motors.  Hydraulic actuators use an incompressible liquid and pneumatic actuators use air. The output signal is mechanical energy.

Unlike machine learning and artificial intelligence, linear actuators are not often in the headlines. However, the role they play in our world today is probably more important than any device ever invented.

For example, in industrial mechatronics systems, actuators are entirely responsible for ensuring a device like a robotic arm can move when an electrical input signal is supplied. Your automobile uses actuators in the engine control system to modulate air flaps for force and optimization of electricity, idle speed, and gas management to get perfect combustion. An actuator is a "mover."

How Linear Actuators Work

Hydraulic Linear Actuators

Hydraulic linear actuators create straight line motion by having an unbalanced pressure applied with hydraulic fluid onto a piston in a hollow tube that results in torque powerful enough to maneuver an outside thing.

The main benefit of a hydraulic linear actuator is the large quantity of torque it can create. This is because fluids are nearly incompressible. Single-acting hydraulic actuators have pistons that may move in only one direction, and spring is required for reverse movement. A double-acting hydraulic actuator uses pressure in both ends to alleviate relative movement from either side.  They are mainly used for transferring quite heavy loads, in precisely the same style that big construction equipment frequently works off of hydraulic pressure.

Pneumatic Linear Actuators

Pneumatic linear actuators are the simplest and most cost-effective actuators.  They work using compressed air to create motion by stretching and extending a piston.  The retraction of the piston is done using a spring or by providing fluid in the opposite end.

Pneumatic linear actuators are ideal for achieving high torque and speed on a relatively compact footprint. Quick, point-to-point movement is their strength, and they do not readily get ruined by hard stops. This rugged nature makes them popular in devices that have to be more explosion-proof or resistant to challenging conditions such as high temperature.

Piezoelectric Actuators

Piezo is a set of solid materials such as ceramic that respond to the electric charge by enlarging or contracting and create energy when mechanical pressure is applied. Piezoelectric actuators make the most of this motion by electrical signs to make short high speed and fast-response strokes.

The motion that piezoelectric actuators create is frequently parallel to the electrical field. Nonetheless, in some instances, when the unit is set to operate on the transverse piezoelectric effect, the motion is orthogonal to the electrical field. The downside of piezo actuators is that they only move a few microns at a time, as they typically only move about 5% of their actual length. So a 100mm piezo will only move around 1mm in stroke which is very tiny. 

Electric Linear Actuators

As its name suggests, electric linear actuators use electric energy to allow movements in a direct line. They operate by moving a piston back and forth according to electrical signals and are used mainly for movements like pulling, pushing, blocking, lifting, ejecting, clamping, or descending.

Linear actuators work with a motor that creates high-speed rotational movement along with a gearbox that slows down its impact. Consequently, this will raise the torque, which will turn into a lead screw, which causes the linear movement of a rotating shaft or drive nut. Shifting the link's polarity from the engine to the battery could make the engine rotate in the opposite direction.


Electric linear actuators are available in distinct strokes, which are accomplished by increasing or reducing the shaft's length. With various gears, different rates may also be attained. Broadly, the greater the rate of the screw, the less the drive. A switch over the primary actuator shaft on top and lower finish halt the twist as it reaches the end of its stroke or movement. Since the rotating reaches its ending, the switch cuts off power to your engine.

    The Capacity of Linear Actuators

    Performance metrics are measurable outputs that enable you to assess the quality of a specific item. Actuators are considered under many performance metrics. The most common ones are torque, speed, and endurance. Lately, energy efficiency can be regarded as significant. Other aspects that could be considered include quantity, mass, working requirements, etc.

    Torque or Force

    Torque is one of the most crucial elements to think about in the operation of an actuator. There are two torque metrics to think about: static and dynamic load. Static load torque or force denotes the actuator's capability when it is at rest. Dynamic load describes this device's torque capability when it's moving.


    The speed of an actuator differs based upon the weight of the load it's assumed to take. Normally, the greater the force, the lower your speed. Thus the rate metric should be looked at once the actuator isn't carrying any load.

    Actuator Durability

    The kind of actuator and also the company's design determines the sturdiness of an actuator. Though hydraulic actuators are considered more durable and rugged compared with electrical actuators, the detailed specs about the quality of the material used will probably be up to the manufacturer.

    Actuator Energy Performance

    With rising concerns on energy conservation and its immediate effect on operational expenses, energy efficiency is a growing metric in all sorts of machines.  Actuators using the least amount of energy necessary will rate highest at energy performance.  

    Linear actuators convert rotational movement in motors to straight or linear push/pull moves. Linear actuators are best for all sorts of applications where leaning, lifting, pulling, or shoving pounds of force will be needed.

    Electric linear actuators are usually the preferred solution if you want a comfortable, secure, and clean motion with accurate precision and smooth movement control.  If you are interested in using electric linear actuators for your next project, Firgelli Automations can supply you with what you need.

    As industry leaders, Firgelli Automations carries the most extensive inventory of linear actuators for every application. You will find the perfect linear motion product and accessories tailored to your project.

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