Servers by jDrones

Help with loiter accuracy (3.6)


(S) #1

I’m having trouble with loiter accuracy.

I was having trouble w/ loiter being wobbly. Stabilize and Acro flew great, but switching to Loiter was very wobbly. I managed to tune that out.
My psc velocity P,I,D are about .7,.5,.3 now, and it’s much better. This is on a 250 size quad. I’m using 3.6 with the new loiter settings.

But, the copter drifts over a few meter area while in loiter. I thought it was bad GPS reception (Thinking maybe the copter thought it was staying still but the GPS signal had it drifting around), but that’s not it. I was hovering and watching the copter in Mission Planner, and the copter icon in Mission Planner tracks the copters movement. So, the copter knows it is wandering around about a 3 meter area when it’s in loiter. A gust of wind will push it to the side for about a meter or two before it starts correcting. It doesn’t appear to be toiletbowling, because it doesn’t go in a circle… it just randomly wanders around.

I don’t have a log at the moment because I’m on my work computer. I can post one later if anyone wants to see it.
But for now, I’m wondering if there are any settings I should be focusing on to increase positional accuracy?
Like I said, I figured out how to tune the feel and the wobbles. But I can’t find information about controlling how hard it tries to hold it’s position.

Thanks for any help.


(S) #2

I just ran out to my car and got my SD card from the copter… So, here’s a log.

I was tuning in this flight… It’s easy to see where I try different settings because I’ve landed and taken off again, and the wobbles are visibly better/worse with different settings. It was best around the 2nd quarter of the flight, so those are the settings I kept. But anyway, the positional accuracy doesn’t seem related to the wobble tuning… It’s been the same throughout.

https://drive.google.com/open?id=17sLGd5gvudOQQ_1lOka4-DxeUyr0ZAFo


(S) #3

Today I increased my PSC filters, and increased the PSC possition XY by a lot… Usually on this small copter all the PID’s need to be lower… And that definitely did help w/ the velocity pid’s. But maybe because the velocity pids are so small, the position ones need to be higher to compensate? I’m not sure. I’ve got it over the suggested maximum of 2. It seems better now. Generally drifting around .5-1 meter, which is great if it stays like this. But also I had 16 sats when I was trying to tune this yesterday. Today I’ve got 20. So maybe that’s making the difference.


(Rolando G) #4

Hey, I fly a much larger 680 quad. For what it’s worth, I did an auto-tune flight inside a large shed and got pretty good results. I did a second auto-tune in loiter mode outside with 1-2mph winds and it started to wonder around like you’re describing and not really correcting its position much. I just cancelled the auto-tune and stayed with the first params. Would it be advisable that you try auto-tune on your small copter perhaps?