Hi everyone, Im trying to tune a 29inch prop quadcopter using Arducopter and the Cube Orange+.
Drone was flying fine but I decided to play with the FFT to improve video stability and now the drone shows oscillations when rolling and pitching in Loiter mode (less in Alt-H).
Does FFT change the PIDs?
I disabled FFT but the oscillation still happens.
Any suggestions?
Why aren’t you using ESC telemetry?
If the FFT is off now it would cause issues.
No. And the Notch filter is used to filter the gyro signal before the PID loop. It’s not a tool to improve video stability but the overall tune of the craft. Perhaps the tune is poor causing the oscillation. Post a link to a.bin flight log.
Thanks a lot for your reply. I have placed the logs in this Dropbox folder:
Unfortunately the ESCs are 4 in 1 with a PDB all custom built and I dont know which firmware they use, I have tried the manufacturer but they dont want to disclose that info.
Let us know who that is so we can avoid buying them.
Update to latest Stable version firmware 1st. Forget about an FFT referenced Notch and configure a throttle referenced. But your tuning is poor with some rather random looking Rate PID changes that are also unconventional causing this:
What tuning guide are you following?
To be tottally honest someone else did the tuning, Ive been just handed over this mess to try and fix it.
Our drone has a composite body, about 110cm diagonal motor to motor and 29inch props. Motors I believe are Lumeniere LU8 pro (not 100% sure, just like with the ESC the drone vendor wont give us that info).
I have attached a picture and diagram of the drone.
Are you sure changing the filter won’t affect the PIDs? I think changing the filter means altering the system’s response. So I think the PIDs should be re-tuned
Maybe you can try the passthrough feature and make esc-configurator.com read the ESCs
Sure they will affect the PID’s if you run a tune process like Auto Tune or Quick Tune. He did neither but simply asked if by enabling FFT and configuring the notch somehow the PID’s will change.
Then start over and use a Tune Process. Arducopter Tuning
Or The Methodic Configurator
So if I dont change the PIDs the FFT shouldnt affect flight performance?
Again, the drone was flying fine and only when we started messing with the FFT (not touching the PIDs) the drone began to have oscillations.
It will affect the flight because then the system has changed and it needs a re-tune of the PIDs. At this point, reduce your gains by about 50% or so such that no oscillations are seen, configure the notch filter and then run autotune. The best option may be to use the default PIDs, then start from there. As Dave mentioned, then follow a tuning guide from the start and change the notch to throttle (or esc rpm based if you have esc telemetry).
Also, I think it is important to note that this is a tethered drone.
TOW is around 15lb with a 6s 7000 back up battery. Tether weight is around 1lb per 100ft and max height is 400ft
