Need Help/Feedback PID Tuning Large Hexacopter

ArduCopter Copter 3.3
1

Hi everybody!

I’ve got a large 1280mm hexacopter, Multistar 5008 330Kv motors, 18x5.5 props. I’ve got it tuned pretty decent in stabilize, but in PosHold (Pixhawk running 3.3) it’s slow and mushy when it brakes. While in PosHold, I think because of the large wingspan, the amount of time it takes to roll or pitch into the brake angle takes much longer than normal. It’s kind of like I need to speed the rate of roll and pitch when braking in PosHold.

I’ve got PHLD_BRAKE_RATE set to default (8) at the moment, tomorrow I’m going to up that one digit at a time and begin slowly increasing I and D via Ch6 to see how it responds.

My question is with a copter this large, is there anything else I should be considering while trying to PID tune?

I’ve tuned many smaller quads and hexes, but this 1280 is nothing like what I’ve dealt with before.

Any help or feedback is GREATLY appreciated!

Dan

1280UC_Manual_PIDS_001.PNG710×358 14.6 KB

2

I welcome you!
I hexacopter-pitch propellers and 90cm 15x55 and also I have a problem with the length of braking. The total take-off weight is 7kg and flying “half power” after releasing the gas kopter long inhibited. Sometimes even 7-8 meters. I’ll follow this post pending a solution to the problem!

3

Did you run autotune ?
If not do it running one axis at time , you can set in full parametr list what axis with be autotuned.

Pay attention, your Yaw P is really small compared to Pitch and Roll this can lead to unwanted behavior of copter

4

Sorry for the delayed response, but sometimes life gets busy. :grin:

I didn’t autotune, mostly because I had no confidence to in being able to keep it up in the air long enough without crashing, it was very unstable.

The good news is that I figured out the the arm tubes weren’t thick enough, there was wayyyyy too much flex which is why it was behaving like that.

I upgraded the frame to one with thicker arms (20mm instead of 16mm) and now it flies perfectly, no problems at all.

Thank you for your feedback, and for being so helpful.

Dan

5

Hello can you helpe me please. Ser myvideo please

https://drive.google.com/file/d/1h3p8Vi7dO4J-93qhZDnTh9P-tPYPGRac/view?usp=drivesdk