Wednesday, 10 May 2017

What's The Difference Between A Linear Actuator And A Linear Servo?

If you're new to micro linear actuators, you might find yourself a little bit confused that there are two different terms used to describe what appear to be identical products: linear actuator, and linear servo. This can be confusing for some people and my aim here is to clear it up and help you understand what is meant by 'actuator' vs 'servo'.

It's important to know that all differences (other than the connector cable) are internal. Linear actuators and linear servos are indeed identical when viewed from the outside. They function exactly the same way, in and out.

So what's the difference between an actuator and a servo?

An actuator operates in the same manner as an electric motor. When power is applied, the motor will spin, and when power is removed, the motor will stop. Actuators are exactly the same. They are dumb devices that only recognize on or off. They are incapable of position control on their own.

A servo is different in that it can receive a command to go to a specific position, and then act on that command. It's not a simple power on-power off equation. A servo can be told what to do and then do it on it's own.
servo actuator

Though they look the same, they're actually quite different in how they function. This makes them ideal for different applications.

Actuators are ideal for projects and situations where what you need is the same range of linear motion all the time. You can apply power and it will extend until the end-limit switch shuts off the power. Reverse the polarity and the same will happen in retraction.

Servos are ideal for more complex applications where you need the device to respond to an external command for a certain position. This is how RC servos work. A linear servo must have 3 or more wires. Power, ground and a signal wire to tell the servo what position it should go to.

Looking at the pictures below, it's easy to understand how some might be a little confused.


micro linear actuators

So to summarize, an actuator is a dumb device that can not complete a task without being told to do so, and a servo is 'smart' in that it can accept an input signal and go to that position on it's own.

It's actually fairly simple, but this distinction can cause some confusion. I hope this article has helped you understand the difference and hopefully give you the foundation you need to choose the best device for your application.






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