Understanding and Tuning Non-Linear PID Controllers for UAVs

[young_penguin]

TL;DR

NLPID and LPID

Hello,
I'm working on a project controlling a UAV (quadcopter)
I'm trying to understand non-linear PID controllers.
I know that a linear PID is given by:

and a non-linear PID the konstant terms are replaced with functions

My question is: how to i find these function and tune the paremeters, i don't seem to understand
Hope someone can help!

 

[BvU]

Hello young penguin,

Don't the authors describe that in their paper ?

You can hardly expect us to do much better on such a general question than a paper (probably the same as the one you looked at) of 10 pages with 32 references.

 

[BvU]

I haven't seen this paper

So where did your formula picture come from ?

i don't seem to understand what f_z1, f_z2, and f_z3 are.

I suppose I could read the paper thoroughly and come up with an answer. But I am certain you can read too

 

[young_penguin]

Hello young penguin,

Don't the authors describe that in their paper ?

View attachment 256188
You can hardly expect us to do much better on such a general question than a paper (probably the same as the one you looked at) of 10 pages with 32 references.

Hello BvU
Sorry i was a little too fast, i was reading the paper.
thanks for the reply. I have looked at the paper you link to, and have some basic questions i hope you can answer for me.

I don't seem to understand how the coefficients k_i1, k_i2, mu and alpha are found
I see what he says in section 5.1. Step reference tracking but i don't understand it.
Hope you can help