Loiter mode(and altitude hold) stuttering, how to tune? (Flightvideo)

[HowDoIfly]

The stand for the gps broke off due to my frustration after the crash, so it is currently not mounted and I do not have a picture of the way it was mounted during that flight.
But this picture show how it was mounted, except that I flipped the compass/gps unit sideways so that the gps is on top like it is supposed to be.

Well, the GPS is upside so that sorts the low sat count /high HDOP problem. The antenna (which is on the other side) wants to be looking at the sky, not the controller chip

brb

[HowDoIfly]

If I lost 3d fix during loiter, would that explain the crash? I mean, would no 3dfix in loiter keep the qudcopter from rising when I apply full throttle?

Chanel 7 is not unused I guess as the gear switch manipulates chanel 7

The intricacies of APM still mostly alude me. I do know that in GPS-reliant modes, the throttle has a deadband set around the middle and manual throttle input has to be made at the more extreme ends of TX stick travel. I haven';t examined the logs for attitude yet, I';m not too up on it but can give it a go.

Channel 7 appears to be enabled throught the Hov Thro dial. The gear switch is right next to it, could it be that while flicking the switch you maybe brushed the dial at the same time? You can retest which is actuating Channel 7 if unsure.

[TheEdge]

Well, the GPS is upside so that sorts the low sat count /high HDOP problem. The antenna (which is on the other side) wants to be looking at the sky, not the controller chip

brb

this side was pointing to the sky during the flight when it crashed, isn';t that right?
I linked to the other picture because that showed the mount and placement on the quadcopter, but I just did not have a picture of it after I flipped the unit as I wrote. Sorry for the confusing picture.

The intricacies of APM still mostly alude me. I do know that in GPS-reliant modes, the throttle has a deadband set around the middle and manual throttle input has to be made at the more extreme ends of TX stick travel. I haven';t examined the logs for attitude yet, I';m not too up on it but can give it a go.

Channel 7 appears to be enabled throught the Hov Thro dial. The gear switch is right next to it, could it be that while flicking the switch you maybe brushed the dial at the same time? You can retest which is actuating Channel 7 if unsure.

The dial was used with channel 6 tuning, but that was with the crius board. The gear switch changed values in chanel 7.
I have disconnected the receiver since the crash, so I cannot verify.

[HowDoIfly]

this side was pointing to the sky during the flight when it crashed, isn';t that right?
I linked to the other picture because that showed the mount and placement on the quadcopter, but I just did not have a picture of it after I flipped the unit as I wrote. Sorry for the confusing picture.

The dial was used with channel 6 tuning, but that was with the crius board. The gear switch changed values in chanel 7.
I have disconnected the receiver since the crash, so I cannot verify.

Yes, GPS as in second picture. So why low sat visibility.... Did it have horizon to horizon view (above everything)?

[TheEdge]

Yes, GPS as in second picture. So why low sat visibility.... Did it have horizon to horizon view (above everything)?

Probably a difficult place for gps reception then, as also two other quads are low on gps count sometimes. When I was out there earlier today with the mobilephone, gps tester showed 24 sats in view and 7 in use..
We have quite a bit of mountains here in western part of Norway.. You see the place in the video in the first post.

[HowDoIfly]

Probably a difficult place for gps reception then, as also two other quads are low on gps count sometimes. When I was out there earlier today with the mobilephone, gps tester showed 24 sats in view and 7 in use..
We have quite a bit of mountains here in western part of Norway.. You see the place in the video in the first post.

Mountains don';t help but your phone sees over 20 satellites and uses more than your quad gps can see, so don';t know what to make of that shortcoming.

I also tried to interpret Thr_In vs Thr_Out data but none, except the first log, seemed to show any kind of correlation (though my analysis skills are sadly lacking).

[TheEdge]

I guess I will just have to put it back together and try it again.
But so far, from your analyzing the low gps count seems like the most likely cause of the crash.

I know the deadband on the throttle for alt.hold and loiter, but when I push the throttle over the deadband it starts to rise when it is working. at the time of the crash, that did not help. Since loiter relies also on gps, I guess the low gps count could explain it. If something similar happens again, I will switch to stabelize instead of pushing throttle to max.

Handson suggest removing power to the vtx, that is a logical thing to do as the camera and the vtx is the only thing that changed since it was working perfectly. But as I now have a functioning osd I could monitor the satcount in flight through the fpv if I keep the vtx connected.
I can just fly around in the same area in stabelize mode, watching the sat count..

Thank you all for help and guidance.

[Hands0n]

I think HowDoIFly is closer to the truth than me. Unless your VTX is putting out some weird EMI. Unlikely but not impossible. If you can watch in the OSD it may help. And I';d agree entirely with the strategy of switching to Stabilise of it goes wrong again. You may need to add some significant throttle to avoid crashing. The resultant altitude gain may help recover control also.

Sent from my Nexus 5 using Tapatalk

[HowDoIfly]

I have heard of mobius causing GPS interference if too close - it';s not unlikely vtx could be too, it';s what electrics does after all. These things though could and should be bench tested first.

What I would do; Setup outdoors without suspect/new devices powered and note Sat count. Power one device and recount Sats. This should be repeatable (if not, it';s intermittent) and if it';s causing degradation; invoking the reverse square law is just a matter of moving objects to other locations if possible. Then retest without flying until satisfied.

[SeamusOD]

Just reading through all this and can see all the same problems I had 

I got fed up one night and bought a Naza lite my friend who also messed about with these AIO boards and megapirate seen how rock solid the loiter was, with perfect RTH everytime out of the box,  so he went off and also ordered one that same day !

When you fit a Naza lite and it justs works with no hassle, you say to yourself why didnt I do that at the start  most of the time it is cost related but at £107 in UK from build our own drone with no hassle it is cheap really.

So my advise is just go and buy a naza lite, I can guarantee you will probably  say exactly what I said above 

Saying all that, now I have a quad that works perfectly everytime I go to fly with my naza setup, I have been back experimenting with my HK AIO and Crius ver1.1 & V2 boards (have three now, plus 3 gps modules, see would have been cheaper to buy a naza at the start  ).

Things I have discovered,
Big differences in the HK AIO boards, same boards flashed same way, loaded with same params one will be better than the others, no matter what you change.

Crius V2 board works better (more consistent) than the Crius ver1.1 or HK AIO

Covering the baro with foam alone is no good, MUST also block light if you can see light through the piece of foam it is no good, I have a blanking dome over my board and when I flew with this removed the loiter was all over the shop, so foam needed changing, try it with a torch and see any alt, vsi etc changes in mission planner.

External compass is also a must, too many things can effect the onboard one, external compass boards are only few pounds, but best bet is GPS/Compass combo, all the big players use external compass there IS a reason, onboard is crap.
Only way it will half work is if the FC is mounted above the motors.

If you change your external compass position or orientation you must re calibrate compass everytime, also regular degaussing the compass is important (going round the compass in circles with a magnet) especially if it was working one minute and not the next.

Save your params regular, so you always have a Known good one to come back to.
Always keep compass as the primary function not gps if playing with mission planners params as loiter wont work properly if you do and Dont even think about a far away RTH unless your loiter is working perfectly.