although probably not what you want to hear.  I think I’m biting off more than anyone else has ever chewed before: autonomous (self-contained) flight control.  I was watching a normal guy’s first flight of his DIY quad.  I’ve no idea of it’s build, but the first test flight was in his 4m x 4m lounge (my estimate) full of furniture, and it went better than Phoebe had ever achieved.

Then I started thinking back through all the other YouTube videos of quads in flight, and they all share the same piece that I am missing – an external PID feedback system whether it’s a human with a transmitter or the external monitoring system as shown by Raffaello D’Andrea’s video.

So I started looking at quadcopter PID images on Google, and they show the same thing: they all have an external feedback system (usually a user with an RC transmitter) where I have my velocity PIDs. This is why I’m having so much trouble with drift control: untuned acceleromer integration to produce drift feedback simply cannot work due to offset / gain inaccuracies; for completely autonomous control, the accelerometer tuning with trend lines to incorporate temperature shifts may well be the only solution until drift becomes large enough for GPS to take over.

I think I may have to return to the tedious trend line tuning to get better trends and hence better drift control.

Still, it’s motivationally exciting to think I may be breaking new ground.  Shame it’s taken me so long to come to this conclusion.