Understanding PID in 4 minutes

[savagealeut1212]

Basics adjustments that need to be made in order to get the same result after a derivative is thrown into play. In order to get the same result before the derivative. I can dig it, good video, but we need some music man!! LOL

[nahchris]

@amrosik Your explanation really helps! Thx a lot :D But can you also try to explain what does the I - component does using that analogy of the car? Thanks again!

[dragginleftnut]

I'm going to go jerk off in my cat's mouth

[mejiarinconleonardo]

Excelent Video!!!

[killmalletgodsrtmout]

Thank you for the great explanation. Really helpful. :)

[FreestyleBrain]

Great summary of all the important things!

[joeballardjrband]

still hasn't sunk in yet :(

[amrosik]

@joeballardjrband ok, then consider the folliwing: look at the picture at 2:19....

this is the case were you only response over linear correction. a practical example: a driver wants to follow a straight line on the floor... everytime he approaches the line, he still has momentum. this momentum causes the car to swing over the line.

now, what does a D-component do? the D-component involves the information about the momentum of the car. how does that D-komponent act?imagine the car approaches...

[amrosik]

@joeballardjrband ... approaches the line. then the error decreases, thereby the dx/dt is negative, and in sum P+D is smaller than P alone(because D is negative). and if this new output is fewer, then the driver will steer fewer, and as a result the car will swing over fewer.

now clear?

[110mhra]

that was really helpfull

[MyRAFA70]

I think that your video is one of the unique that explains very clear the PID tunning. Good job!

[dukkySM64]

How 2 get first hit rapiering

[clearair]

Very clear definition, thanks.

[anumsheraz]

Best video ever !!! Thanks to the man behind it. Took me obviously more thn 4 min. :p

[tagar07]

was very helpful !! better than a lot available

Thanks alot

[mrCbeems]

A graphic demostration of a PID in operation in a mechanism that most can relate to (like an airplane or car) would make understanding PID's A LOT easier.

[boxiness]

A good analogy is changing lanes on a freeway, where we have the feedback loop consisting of: eye - sensor; reference - car position; error - displacement to other lane; actuating signal - angle of steering wheel; disturbance - wind; plant/system - vehicle.

If u only have P controller, u can only instantaneously set the steering wheel angle to something proportional to the error. This will get you to the other lane if there were no disturbances. (to be cont.)

[boxiness]

But if there's some wind. For example you're trying to go to the right lane but we have some wind (disturbance) applied to the vehicle in the form of a step function at some time after you're turning into the lane, then it's possible you may end up with a constant offset. This occurs when the steering angle calculated from the P gain x error is equivalent to the force of the wind, thus canceling each other out and the car will move in a straight line, with a constant error.

[boxiness]

You could of course set the P gain to be very high to overcome potential disturbances. However if there were no wind e.g., then a very high P gain will cause the vehicle to overshoot the target lane. The system can even potentially be unstable and error go to infinity.

That's why the PI controller is so popular. The additional I gain solves the offset problem by looking at the cumulative error and increasing / decreasing the steering angle accordingly.

[boxiness]

So in the case where a step function wind is preventing the vehicle from turning into the right lane, the I gain, which depends on the cumulative error, will eventually overpower the force of the disturbance and allow the vehicle to move to the correct lane.

However this doesn't fix the problem of overshoot (settling time). In fact the PI controller has a higher settling time than the P controller. This should be obvious. So this is where the D term gain comes in.

[boxiness]

The D term gain is added to the PI controller now. The D term essentially looks at the rate at which the error is changing and try to counteract that change. So imagine a situation where the vehicle is oscillating around the target position in the lane. When it's moving from the center into the right shoulder, the error starts to increase, and since the D gain is proportional, the faster the error increases, the harder the D term tries to pull the vehicle back. u end up w/ reduced settling time.

[iammestamanRS]

How to be confused as fuck in four minutes!

[TheMimimocha510]

How does a controller work to maintain equilibrium in a closed loop system?

[mrCbeems]

Excellent.. please upload more on this topic. For example.. in most systems there are 2 PID's. One controls Speed and the other Current (Torque). Can you elaborate of these?

[thelegand1]

Ahh it all makes sense now!

[milburncamilo]

Thanks, Nice simple explanation.

[tariqusman1]

Please can u explain the Digital PID control

[chevon1920]

Well that took more than 4 minutes, but I do definitely understand it much better. THANKS SO MUCH!!!!!

[EngrKenXi]

I learned a lot from this. Thank you very much sir!

[electronicscontrol]

thanks