[sherring]

Hi all! I am kinda new to drones and RC's and have been building a drone for quite a while now - about 1.5 yrs, with no success. I am coming from crius multiwii board, with no success, currently using CC3D evo board. My setup is listed bellow.
Currently, I cannot hover and I found out two strange behaviours:
1) Motors go high speed - not full speed, tough - with little thurst. I expected a proportional thurst to throttle. Should I expect it?
2) Uneven motors' speed for a given, minimal thurst command, monitoring from the scopes tab. To rule out vibration issues, I have disconnected every ESC, level the drone, do not touch it at all and apply some throttle. Still, motors command are completely uneven, as per attachment.
How can I debug it?

My specs:
SK450 frame
4 Turnigy multistar 30A
4 Turnigy D2830/11
4 1045 props
4S 2.65aH 20-30C
CC3D evo
Turnigy 9X8C PWM rx
Turnigy TGY 9X tx


Thanks in advance.
Paulo Sherring.

[Mallowsthecat]

please make sure to do this:

goto stabilization
goto basic settings
make sure you put a check on:
"Zero integral when throttle is low"
then save settings

Trim down your integral inner loop for now
make is same value as proportional

try to fly when you have success try experimenting by raising
integral in the inner loop

[sherring]

Thanks for the reply, I was able to hover a foot , way more than I have ever achieved. But, I couldn't understand why it worked. In cgs, it says that inner loop changes rate effect, but, in config, I am no using rate,  only attitude, attitude, lock and manual.
Any thought?

[TheOtherCliff]

Attitude mode uses outer loop.  Outer loop uses inner loop.

[sherring]

Nice, thank you so much! Will start dealing with on air oscillations now

[TheOtherCliff]

Most people leave outer loop alone, but the correct order of tuning is to fly Rate mode and adjust Inner Loop PIDs, then fly Attitude mode and adjust Outer loop PIDs.

[sherring]

Hi! Is there any technical reading available for cgs? I looked at wiki and could find a definition for throttle. Does it modulate available power for motors? Is there some way to make it signify an input signal to how much should the drone rise or dive?
Although I am rusty in control engineering, it would be nice to meet hobby and engineering for real
Thanks again!
Paulo Sherring.

[TheOtherCliff]

CC3D does not have a baro.  Baro is required to do "Altitude Hold".

Like driving a car.  To get to 60mph you use half the pedal, but once you get there, you cut it way back, and you have to add or subtract on hills to maintain 60.  No baro is like no speedometer, no car cruise control; you are directly controlling throttle.  Altitude Hold is like cruise control on a car. 

Revo class FCs have a baro and can do Altitude Hold and even better, Altitude Vario.  AV with throttle in center (with deadband) is AH, else the stick gives proportional speed.  If full stick is configured to climb at 3m/s then 75% stick climbs at an exact metered and servoed 1.5m/s and 25% stick likewise descends at 1.5m/s with a full PID implementation to make sure it acts the same even if you remove your heavy camera.

The wiki has some info on flight modes and AH / AV is a flight mode throttle option, but not for CC3D.  Here is a search to get you started.
https://librepilot.atlassian.net/wiki/dosearchsite.action?cql=siteSearch+~+%22flight+mode+attitude%22&queryString=flight+mode+attitude

[sherring]

I though about integrating acceleration 2 times to get vertical displacement, but I guess with time, error would increase very much, due to noise and sensor precision. (Or else, someone else who has been around a lot longer than me would have already got it done, right?!)
Any way, thanks for the reading!

[memz180]

This was happening to me as well. The solution was within the stabilization tab in Librepilot, there is a check box if you scroll all the way down.

It immediately fixed the issue with the throttle.