Actuators (Explained) Video Lecture - Electrical Engineering (EE)

Hello, everyone, and welcome to this week's video.
Today, I'm going to be talking about actuators.
Now, actuators are a very important topic because they're used in practically all types of machinery.
So, it's a very useful thing to understand how they work.
Um, I'm going to talk about three or four different types, and also how these, or where these actuators are utilized in the automotive industry.
So, starting with the screw-type actuator, one of the most basic types of the linear actuator.
What you've got going on is you've got an electric motor,
and that motor turns a threaded rod -- that's this, right here.
And so, attached to this threaded rod, we've got this, uh, little green device here, and so this is a nut, this green device.
And it's threaded on the inside, so as this motor turns, it moves one way,
like it could move vertically or move down, uh, depending on which way the motor is rotating.
So... also if you have this to the side, obviously it can move left to right rather than up and down.
And so, the reason why it goes up or down is because it's got this blue guard here that you see that prevents this nut from rotating with the threaded rod.
So, when a motor rotates, it's forced to go up or down, or left or right, or however you have this set up.
So, some of the automotive uses, where something like this could be used:
Drag reduction system, as I've already gone over, used in Formula 1.
Also, it could be used for cruise control, and I'll have a video on that later, so that'll make more sense at that time.
Another type of actuator: hydraulic and pneumatic.
Uh, hydraulic using oil pressure; pneumatic using air pressure.
So here, I've drawn a hydraulic system.
Uh, everything in black pertains to the, uh, hydraulic system, and I've also got some words in red, and that pertains to the pneumatic system.
So, what we've got going on...
You've got a reservoir, a pump, a valve,
and you've got this system here, which is the oil pressure to move this green device here.
So, say you want to move something in this direction.
And this is very common in construction equipment, uh, that very common to use hydraulics.
So you've got the pump here, and that's going to use this valve
This valve's going to direct which way the oil goes, so... a little coming on this side.
This is basically a piston-cylinder system.
So, as oil forced in here, oil is forced out here.
It moves through the valve back into the reservoir, and from the reservoir into the pump.
And the screen device, this piston, is pushed to the right.
So you can orient this in any direction.
And with this particular system, you can move it in both directions.
You can move this piston in or out.
Some, uh, hydraulic systems, we just rely on gravity or other forces to go back down,
so they might only push one way and then come back the other way, just using gravity.
This one, you can just reverse the pump.
So, then... or you don't reverse the pump, you reverse the valves. So the pump pumps in here...
and it'll pump oil in this side, rather than this side, and push the piston this way.
And that oil will come through here and go into the reservoir...
...uh, and then back into the pump, obviously.
So, that's one way of doing it. Now, if you're using a pneumatic system, you wouldn't have to have a reservoir.
You can just have it open to the atmosphere.
And you'd have an air compressor here that would pump in the air to either side of which you wanted to move this piston.
The next system is a vacuum -- oh!
I should've mentioned... so, some of the uses for this, uh, this hydraulic, or pneumatics:
Obviously using construction all the time, you see those big backhoes and everything. Those are all using hydraulics.
Uh, forklifts also use hydraulics, very common.
Power steering is basically the system I've drawn here. So it moves a rack-and-pinion system.
So that's in using cars.
The next type of actuator: a vacuum actuator.
Uh, it's a... it's a pretty unique system and it's actually kind of a cool idea going on.
So, what happens is you've got these springs here, and you've got this green device which you want to move left or right.
That's the whole purpose of an actuator: to move something.
And you create a vacuum on this side of this chamber, so you can have a pump
or something like a connection to an intake manifold where there is an vacuum,
and using this valve, you can control the amount of the vacuum,
and then you can move this green device left or right.
So, you've got springs, which want to push it this way,
except you've got atmospheric pressure on one side and a vacuum on the other.
So as that vacuum increases, the atmospheric pressure...
There's a pressure difference on the left and the right, so it pushes it in and it moves that in.
So, it's kind of an opposite idea of like a linear actuator; you want to push something out,
rather... it usually is used to pull something in; however, you release that back.
You get close to atmospheric pressure in here, and it will push back out; so it does work both ways.
So these are three different types of actuators.
The vacuum actuator can be used in things like brake assist, through power brakes.
There's a very similar system to this being used, uh, which I'll go over in a future video.
And also, cruise control. It's a very common use of vacuum actuators, so that's another use for that.
So, three different types of actuators, all very common throughout the mechanical world and various will understand.
So, I hope you guys learned something from this.