Quadcopter acts as if flying in a tornado with mild to no wind

apm
multirotor

#1

My quadcopter seems to go all over the place without me telling it to and I don’t know why. Its loiter doesn’t work very well and goes into VRS very quickly and easily and requires lots of power to recover. When I stop moving and it “corrects” itself it starts tipping aggressively from side to side. It has a 600mm frame and turnigy 5017 motors and 15in props. Can you help me fix these problems? Thanks. Or could you recommend a different flight controller? I’m honestly getting tired of the endless stream of problems that seem to be coming from the APM.


#2

Hi
Alex @unmannedtech is the guru on APM so no doubt he will give you advise

For my two-pennyworth, if you are new to the hobby and do not want to have lots of settings to configure you could do worse than swap it out for a DJI NAZA M system.
They are easy to set up, fly well, are well suited to a 600mm frame and can be bought, the LITE version, for as little as £75 (genuine part, beware of cheap copies) A free software upgrade will bring it up to V2 spec which is a really stable flyer.
Not as versatile as the APM/Pixhawk devices but will get you in the air quicker

Cheers
Steve :slight_smile:


#3

Thanks, although $75 sounds really expensive. Is that with GPS/battery monitor or without? Or are my parts compatible? Anyways, I would prefer to fix this if possible…


#4

Because you are using non standard motor with 15inch props its likely the poor performance is due to bad PID settings, but that in itself can be a tedious process to tune, but there are quite alot of guides around on the internet on that. But other issues could be high vibrations upsetting the IMU on the APM board so it is rather difficult to say without seeing it fly.

As for poor loiter that is usually down to bad compass calibration, or a bad mounting location so the compass is getting lots of interference from the motors/ other electronics on your drone.


#5

I got the 15in prop idea from this page: https://www.rcgroups.com/forums/showthread.php?2233568-Turnigy-5017-620kv-Brushless-Multi-Rotor-Motor
which says that you can and should use it on 3s with this motor. I will try to send a video of it flying when I can. I am using velcro to attach the APM to the quad, does that eliminate enough vibrations or should I get a real anti-vibration mount for the APM? I’ll try redoing the compass calibration and compass motor calibration. The compass is on the center-right of the quadcopter. Here’s a (bad quality from my webcam) picture:


#6

I might just try resetting everything and redoing all the calibrations. I did have some old settings still lurking around from my V-shaped frame which was lighter and differently shaped… I’m thinking the problem is that my P value is too high or D value is too low (in the PID tuning.) Does that sound like the problem? Also, I might have to wait until the weekend to get a good video of the problem, hopefully the weather will be good by then.


#7

If your APM is mounted just with Velcro that could actually cause more vibrations if it’s not totally secure and the board itself can move slightly independent on the frame. Check this post for some more info on vibration damping

But a video would be helpful


#8

I just flew it outside with no wind and it flew perfectly! I would post the video I tried to take but my camera somehow didn’t get it :slight_frown:. Still, it’s horrible in wind. I’ll try to get it on a windier day.


#9

I just charged the battery and got a good video of it in no wind (same day as last post.) It flies like a phantom and has rock-solid stabilization. That usually changes in the wind, though. Also, maybe it’s possible that the “mild” wind I mentioned in the title wasn’t so mild after all. I didn’t measure the speed, but you never know. Anyway, here’s the video, although it won’t help us troubleshoot because there’s no trouble to see! https://www.youtube.com/watch?v=fTslyH-iDa0