Hi all,
High hopes dashed this evening probably through my own stupidity but I would welcome a diagnosis of the attached log, please.
This is a Tarot 250 mini quad with APM Mini 3.1 and 6M gps. All seems good, took off about 3 feet and kept her fairly steady in stab mode then went into alth at which point she started to rise steadily without response to any of my inputs. Got to roof level so I took her out of alth, even tried rth but she took a quick right and started heading down our street. I shot through the house and luckily a guy I know down the road saw it land in somebody's front garden. No apparent damage apart from a couple of props and a lost prop nut.
Seems there were some GPS glitches but I don't understand why she wouldn't go back into stab and let me bring her back down.
I'm successfully flying a powerful Spy 600 with Pixhawk and have never even had the slightest brown trouser moment with that..
Thanks,
Peter.
Replies
Well, I went my local flying area this evening and all went really well! She needs some tuning but no unexpected behaviour, alth was pretty chaotic at times, very edgy but loiter was pretty steady and stab was fine.. GPS seemed to be working well so I guess this topic can be put to rest.
https://youtu.be/2tQLH42TLoY
The Mini is in a case and has some breathable foam over it so I don't know alth was erratic, I'll try some other foam maybe..
Thanks for everybody's input!
Peter.
2015-03-17 18-07-16.log
2015-03-17 18-21-53.log
2015-03-17 18-21-53.log.gpx
https://youtu.be/5-dgB9FEJZw
Glad you got it back. RTH is definitely dodgy with 6 sats and untested loiter.
When you get this flying again could you report how Alt Hold works. I have discovered I have terrible baro performance compared to my 2 APM 2.6s and VR uBrain. And yes it is covered, protected etc. You can see it on the bench and baro logs. Loiter becomes Land at low altitudes. People say 3.15 has been better for them with this board with regard these issues when they arise, though I am unsure why. I have ordered another from a different vendor to see if I can get better performance before I abandon the APM mini. At $40 (from Witespy) you have to wonder if you are getting genuine baro components in them. When I have more data I should probably post my findings.
Hi Marc,
I know it's a little early to be thinking this but changing to a Pixhawk has been a thought.. I've never had a fly away before, it's always been a dread of mine but thankfully this was so much better than it could have been, just think where 2 or 3 minutes of flight could have taken it.. One invests a lot of time and money building these craft and to watch one disappear must be pretty soul destroying.
Still, I was fortunate so I will persevere although I won't let her fly again until she responds as she should whilst still being held, one advantage of such a small frame.
I'll post up any progress I make.
A pixhawk can fly away just as easily as a mini APM if prior prep and tests have not been done.
Basically don't rely on any of the gps modes, especially RTL without proper setup and testing.
If you haven't been doing this prep/test then you have been lucky that this your first fly away. Not having a dig, just saying...its important. No one wants you to lose your copter either.
I almost think that arducopter needs even more hand holding, not allowing the gps modes until certain testing or flags have been set. These flags could be parameters that can be set true at risk....but it would ensure conscious effort to do so hopefully making the operator think about what they are doing.
100% right on that Stuart. I have a simple rig in my basement where I test before flying. I never fly anything outside until it can do a controlled 6 inch tethered hover and vibes are acceptable and barometer is behaving. We all learn the hard way at some point........
Wouldnt the log show when the different flight modes were used? I may have missed it in the thread if the stabilize-mode where even used? Or were there two fails: RC signal loss & Too few satellites? Maybe there wasnt any signal loss because of the panic? :-)
Ordering a Mini APM 3.1 later tonight... =)
Hi Mikael,
It does show 2 flight modes, stab and rtl.. I'm 99% certain that there wasn't any radio loss.
I have fitted a new mount for the Mini Apm this evening.
Let us know how you get on with yours..
Peter.
DSC_0296.JPG
You could essentially have either vibrations or downdraft issues on the baro. See copter.ardupilot.com for info on how to analyse and fix that.
You live quite close to some nice open spaces, fly there rather than over people's houses would be my advice.
Thanks Bill, yes will definitely go to an open space next time. Switching to rtl was a reaction to loss of control but thinking back I can't be sure that I did switch back to stab, panic may have ruled as when I held the quad and switched back to stab it did respond.
I wondered about vibrations but why would that just affect alth and not stab?
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