cant find the right PID setting

Just tried this to find the PID for the sonar Altitude Hold.

By finding the maximum P where the AH starts to oscillate (copter goes up-down-up-down in rapid a/decends)

by timing, with a stopwatch for 10 cycles the average gave me Pu Unfortunately i hade a blade-off during te last test flight so could not implement the calculated PID. Still wondering about how high the gain (intmax) of this loop could be calculated.

[adapted from wiki]

Ziegler–Nichols method

The I

and D gains are first set to zero. The P gain is increased until it reaches the ultimate gain, $K u$ , at which the output of the loop starts to oscillate. $K u$ and the oscillation period $P u$ are used to set the gains as shown:

Ziegler–Nichols method
Control Type	$K p$	$K i$	$K d$
P	$0.50 K u$	-	-
PI	$0.45 K u$	$1.2 K p / P u$	-
PID	$0.60 K u$	$2 K p / P u$	$K p P u / 8$

$[/end snip]$

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valentin colon July 2, 2011 at 8:45pm

nice!!!!
Developer

Jason Short June 27, 2011 at 9:54pm

Here is a quick demo of the rotatation PIDs:

Click background to give Flash keyboard focus
Developer

Jason Short June 27, 2011 at 5:52pm

Here is how I found the current gains:

This is a quick mock up in Flash of the Alt hold PID.
Pieter van Woerkom June 27, 2011 at 4:42pm

Just tried this to find the PID for the sonar Altitude Hold.

By finding the maximum P where the AH starts to oscillate (copter goes up-down-up-down in rapid a/decends)

by timing, with a stopwatch for 10 cycles the average gave me Pu Unfortunately i hade a blade-off during te last test flight so could not implement the calculated PID. Still wondering about how high the gain (intmax) of this loop could be calculated.

[adapted from wiki]
Ziegler–Nichols method

$The I$ and D gains are first set to zero. The P gain is increased until it reaches the ultimate gain, $K u$ , at which the output of the loop starts to oscillate. $K u$ and the oscillation period $P u$ are used to set the gains as shown:

Ziegler–Nichols method
Control Type $K p$ $K i$ $K d$

P $0.50 K u$ - -

PI $0.45 K u$ $1.2 K p / P u$ -

PID $0.60 K u$ $2 K p / P u$ $K p P u / 8$

$[/end snip]$
Russell B. Sutton June 27, 2011 at 2:41pm

try P = .3 I = .025 D = .13 for pitch & roll
emile June 27, 2011 at 11:06am

Please share some more details on your setup.

Like motors, escs frame,prop size etc.

E.
Rob. S June 27, 2011 at 2:31am

Just another Question to add to this
could it b my esc's at the moment its all default?

wat changes should i make to them??

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cant find the right PID setting

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