This is my first post here and i hope to find little help as i´m not an APM Expert!
I recently build a DIY V-Octo from scratch, that is flying ready at last. As FC i have a APM 2.6 Board and
have it set up with standard Arducopter FW AC3.2 for Octo with the option V-Frame!
The copter behaves fine after i did Autotune and changed some parameters, so i think! But i want to enhance
it a bit as i think there could be a better performance.
This i see most time in windy conditions. The Copter maintains the position on "Position Hold" pretty well,
but with a bit jerking on wind gusts!
Or when it descends quickly the copter begins sometimes to wobble around in all axis
On calm days it feels "Rock solid"
As i read this configuration should fly optimized with an angle of 14° Motor rails to Y-axis in the
known screenshot to find everywhere when you search for "AP V-Frame Octocopter". So i did some measuring
and found out my "Motorrail angle" is just ~ 12°.
I decided to give the finishing touches in changing the "Motor Mixing" in the Arducopter code!
But as i am no expert in these things i´m looking for your help.
There is so much to do that i feel a little overwhelmed with all this new phrases to read, as i also have
not the best english skills to understand all this "Technical things" and every answer i find leads to
more questions ;-)
There are questions about:
"When i modify the code, compile it and flash it back on the APM what happens with my hard made Settings, Parameters, PID´s?
Will they be overwritten, or can i import an "Exported" "Advanced Parameters" again.
What could happen if i did some mess and want to load the original back. Do i have to set it up all again?
Where to change the right "motor mixing table" in the code, i found at least 2 parts that look like a "Mixing Table"
What values should i change to match my 12° Angle?
I know here are the experts to find ;-)
I really hope for help, as i love my V-Octocopter because it´s not that commodity "Starshaped" copter you see on every
corner ;-). I like the unique things not everyone has!
Im having the same issues seen you posted a while back were you able to figure out?
Hey Michael - I hope that you've figured out the problem by now. But if not ...
The problem isn't motor mixing. That would only have a small impact on the control issues you see.
The problem is the PID values for each motor. There are a lot of videos and posts on how to tune the PID of your motors. But a quick introduction.
- P is proportional so impacts how quickly the motor responds to a wind perturbation.
- D is derivative so impacts how quickly the motor is stopped from overshooting (a high P & too low D -> motor revs too long).
- I is integral (sum) so impacts the long-term memory and helps the ship fall stably through its own wake.
Your PIDs are too low for your ship size.
- Too high and the ship quivers
- Too low and the ship can't respond fast enough to perturbations