Hi all, I've had my 3DR quad for a while now and amazingly, despite my ~5x5m flying area, have avoided crashing it!
However one thing I've noticed is that the copter does seem a little unstable, even in a light breeze. I also seem to have a "mushy" yaw, as in the wind can actually yaw it a few degrees and it won't really try and correct it (Does seem to yaw itself ever so slightly in flight too - I have the APM2.6 with external GPS/mag and have auto declination on).
It flies perfectly stable in no breeze, but I've just noticed that once there's even a light breeze, the copter seems to kind of wobble around. Not like oscillation wobble, just being knocked about by the wind and not really correcting for it fast enough.
I do intend to try the autotune feature, but I'm waiting for a nice still day for that, which hasn't happened yet. I'm using the default arducopter PID's, which are apparently great for the 3DR quad, but I'm just wondering if there's something I can tweak to try get it's yaw locked in a bit better, and "wobblyness" down, for lack of better terminology :D
Dan
Replies
As long as the copter is not holding well anymore under disturbance(wind), your PID is bad with a low gain. Just like Rizki said increasing P gain will help but dont get your copter into too much wobble, it's on the edge of stability when it starts to oscillate.
My Hexa behaves exactly the same it wants to roll or pitch in small amount like random when there are even small air movement but will perfectly hover with no input when wind is non existent. I used to have this problem on my Multiwii because of the vibration, and wind seems to amplified the effect. Reducing and isolating the vibration solved the problem but not on the APM so it must be something else. The effect is less if i fly in more open area but it still there. With my multiwii the wind will just push it around no pitching or rolling like in the APM.
One thing that make it better/stable in the wind but not solved it completely is to increase Rate I to some big value or induce a small but fast oscillation by increasing Rate P. Once in small but quick oscillation it hold winds more steadily/level. Just a though.
I would be hold back on changing too much until you have had a chance to fly in a bigger area. Then see what you need to do, its amazing the stability free space away from obstructions gives you. It must be pretty dialed in if you have avoided an off to date.