PID Tuning - A symptom based approach


#1

Peeps,
2 part Q

Q1
I get what progressive derivative and integral do… to a degree. It seems that every PID tuning video/ instruction I watch seems to lend heavily on the subject before getting into a tune however.
Then, most of the videos end up tuning out a problem on their quads and I walk away from it wondering what the hell I should do. So why aren’t there any (that I can find) videos with a list of problems and how to tune that out? Is this just inherently an impossible task to achieve? Does anyone know of any good vids?

Q2
I’ve been playing with Antigravity. Why? Because when when I drop out of the sky then hit the throttle I get the wobbles for a bit. So I upped AntiGrav to about 4 and my I gain up by 5 on the three axis. No change. Should I up A.G. a bit more? Should I up the I gain a bit more?

Cheers.


#2

HI Benjo,

A1:

I am not the person to give detailed instruction about how to PID tune a quad as I am still learning to fly and have had any reason (so far) to change them on my quad. However, I can recommend Joshua Bardwell for PID tuning videos. He has done lots of them and explains the process very well. I’m sure the DNUTS team will also be able to provide a very good explanation.

This is the first of 14 other parts as well as some other interesting PID tuning videos he has uploaded.

A2:

Watching some of Bardwell’s videos may also solve this problem for you as well. I haven’t changed my A.G gain but I will be paying close attention to other replies to you about this as I also experience the same wobble.

I hope this helps,

Tim


#3

In answer to Q1 (sort of) what you are getting is prop wash, BF has been handling this sort of issue better over time and there are some things you can do to eliminate these (or reduce them) notch filters and that sort of thing and there are heaps of videos about these.
Having said that, if your quad is flying fine, there is a school of thought that says learn to fly what you have. What I mean is that you can eliminate the prop wash issues by trying to fly more smoothly and concentrating on the way you fly.
OK didn’t answer the question, but it is an approach.
Be careful with D term tuning and turning off filters as you can destroy motors if you are not careful, especially if you have a noisy quad.


#4

Its funny you say that because I get the same wobble when I do what feels like a bad a turn. I immediately think that I need to tune it out but part of me feels like “well actually I could have just taken that corner a lot better and not dropped into he prop wash”.
Sage advice.
Having said that, the quad seems to respond quite well. Other than what I mentioned above I haven’t played with the tune. Ill be sure to research the D tune before messing with that, cheers.

At the moment my quad isn’t flying at all, and its not due to prop wash. I nicked a branch and cut into my ESC which blew a motor. So back to the drawing board. When I get some new parts ill have to tune it all over again anyway.