Heavy quad PID suggestions

Hello all.

I’m Jean, new here. I believe I am currently in need of some good advice from more experienced individuals, so here’s my little problem.

This past year I’ve been working on building a new drone, using the Cube flight controller. The drone is on the larger size (I’ve built several drones before but this is by far the largest), weighing in 23kg but I will leave some numbers further down this post.

Following my first test flight a few days ago, I am convinced the stock PIDs need to be seriously adjusted before I can proceed with my next flight. My target is to get the drone flyable enough to use Auto Tune, as this feature has served me well on lesser drones in the past and I really think it’s a great feature, however this drone costs a bit too much to accept it flipping over… The video below explains it all, PIDs at end of clip.

I am aware enough that I can’t ask for PID settings, they are different for each drone, so if I could get some input with regards to whether people see something off with them or not (for a large drone), I’d be grateful to know so I can be nudged in the right starting direction.

Here are some specs if they help.

Frame - Ridged carbon H frame
Motors - T-motor U13ii
ESC - T-motor flame 180A
Propellers - T-motor carbon 32 inch
System voltage - 12S
Take off weight - 23kg
Radio - Frsky X9E with R9M module

PS: I’ve just realized I’m using the same PIDs from my previous drone! I should probably fall back to defaults and try again!

Appreciate your help! Thank you.
Jean V

Use this tuning guide for the process:
and this spreadsheet to derive the values:

Thank you Shawn. I will certainly spend some time going through this.

Really appreciated.

nice “monster” what you got there :wink:

the parameters shown in the video look a bit weird to me:

  • Rates ( P ) pretty low
  • Stablize extremely high (18!)

of course your copter is more than 5kg heavier than mine, but generally the inner control loop (rates) should work well before the outer loop (stablize) should be tuned.

Thank you for your feedback and comment.

I have finished a second test flight just 2 days ago, with much better results thanks to the Tuning instructions kindly provided to me by Shawn. I reset all PIDs and rates, but put P down slightly and that’s all it took. While it is far from perfect, it is now in a stable PID loop and ready for autotune :slight_smile:

Also the PIDs you saw were obtained on a small hexacopter through autotune (which was put together strictly for me to learn Pixhawk/Ardupilot). I remember a gentle breeze that day, perhaps that had something to do with the high stabilize?

Once again, appreciate your time and input. :slight_smile:

I whish you luck and happy landings :metal:

that*s a really good idea. So do you fly acro mode, just as a test for the inner control loop?