Servers by jDrones

Tradheli not flying well in RTL and Auto

Hi,

today I was planning on doing a small mission testflight with a light wind 5(10) m/s and after switching to Auto mode I noticed that the aircraft was doing some very weird movements towards the waypoint. Finally it reached it, but it wasn’t flying in a straight line (circling around) while keeping the altitude. Same thing also happened when I turned it to RTL. However, in Loiter it was flying very nicely straight when I gave it cyclic. As in the first flight it also gave me GPS Glitch I thought that maybe that had something to do with it, but on the second flight there wasn’t any glitch and the behaviour was the same.
I have added autopilot log file from the first flight and screenrecord video of the second flight here
In the video (2nd flight) I fly a bit in Loiter and then switch to RTL (around 07:50). If anyone has any idea about what might cause such weird behaviour between Loiter and RTL/Auto modes then please let me know.
One more thing, I successfully flew the same mission yesterday (1 hour of consecutive flight). Only difference was that previous day there wasn’t any wind. Thanks for your help!

@SiimH I think it was you log that you posted in another thread where you were concerned with aircraft lurking around the landing point. I looked at that log and it was clear that your desired and actual velocities in the position controller were not in phase. I also notice oscillations in your attitude data around 1 hz if I remember correctly. So you have to tune the attitude controller better so the actual attitude tracks the desired attitude with in 1 to 2 deg. Then the position controller may need to be adjusted.

Hi Bill,

ok, thanks! We’ll get into it tomorrow and start sorting it out. On what the 1 Hz oscillation might refer to? Some filtering error or as a tuning oscillation?

Hi again

so we practiced tuning the heli in SITL before actually trying it on real aircraft and found out which parameter does which. So, after tuning the position controller VELXY_D and VELXY_I parameters to 0.5 and 0.3 respectfully the behaviour was increased significantly and we are able to decent autoflight in quite strong and gusty winds (~16 m/s winds). We understand that this current tune was sort of a “quick fix” and we are probably returning to to re-doing a proper tune after we have finished doing flights that are due very soon. Thanks for your help @bnsgeyer!
Also, one more question - does anyone happen to know if or how many users are using external gyro together with ArduCopter 4.0 firmware on TradHeli platforms? I understand it’s a bit of an odd setup, but just out of curiosity we would like to others experience with it. We once started with external gyro as the setup in Acro mode was way more easier and seemed to be safer on a 900 class heli that we are using. And that is one of the reasons we have stuck to this method so far, but understandably the autopilot code has gotten better and with the addition of Autotune functionality coming we are considering using a bit more traditional setup. Currenty we are a bit swamped with getting our helis to use, but @bnsgeyer if you ever need information about developing Autotune functionality also for 900-class helis, then feel free to let me know and I will definitely try to help out!

Servers by jDrones