Iris+ sudden fall

Posted by Mhct on July 3, 2015 at 3:59am

Hi all,

I was flying an Iris+ after performing all calibrations, etc. The copter had an extra radio (operating at 5.8GHz and a raspberry pi, on the same battery).

The flight was very ok, the Iris could handle the wind which was blowing, etc, when suddenly it simply fell from the sky.

Apparently only one of the engines suddenly stopped. I contacted 3DR and was told that the logs don't show anything special. They believe that there is either a problem in one of the motors or in the whole ESC. I would like to hear a second opinion, though.

I am posting the video of the crash and the log files here, asking if anyone can spot anything
interesting in the log files. I already took a look at the logs, but couldn't find anything.

Thanks for any reply.

Mario h.c.t.

15-06-25_17-34-44.bin

You need to be a member of diydrones to add comments!

Join diydrones

crash, iris+

Email me when people reply –

Replies

Scott July 4, 2015 at 11:23pm

First thing I see is that the flight did not start with a fully charged battery at 11.4 volts. A fully charged battery should show about 12.3 volts or so. At the time of the crash your battery showed 10.4 volt. That is very low. Based on that I'd say that battery just could not keep it in the air any longer. Check your failsafe settings for low battery and definitely pay attention to your telemetry. You should have landed before it got to that critical voltage.
- Mhct > Scott July 9, 2015 at 5:24am
  
  Thanks for drawing my attention to that Scott.
  
  The failsafe settings were, indeed, configured to LAND if the battery was lower than 10.5V, and if the battery had zero load (mAh = 0).
  
  I think you are right, it may simply be a problem with the load of the battery, since plotting the altitude versus battery, indicates that the battery suddenly went to 0V and the drone started falling...
  
  Thanks again for pointing that out.
- Scott > Scott July 8, 2015 at 9:41am
  
  Well...?
Richard Zade July 3, 2015 at 12:06pm

This kind of stuff scares the hell out of me. I have seen way to much of it and knowing that is over a thousand dollars plummeting to the ground like a rock is insane!
- Mhct > Richard Zade July 4, 2015 at 12:22pm
  
  Sure, it shouldn't simply fall..
  
  But if you are lucky you can always change the broken parts... :)
- Gregg > Mhct July 4, 2015 at 7:40pm
  
  That does not look likw one motor failure..looks like total power cut off. Usually if a motor quits it will do an angled dive to the ground either forward, back left or right. My Iris was loosing power and crashing when I turned. 3dr told me to down load the latest firmware to fix the power loss problem. I flew it a couple of times then sold it.
- Christoph > Richard Zade July 3, 2015 at 4:49pm
  
  It seems scary but the point is to figure out what happened. I believe in the majority of cases something went wrong which could have been prevented.
  
  Like in above case. As said I am not an expert in log analysing but here it rather looks like the IRIS was crashed during a first take off attempt. Something might have been damaged during that (ESC, Motor, Connections) which then caused the second more severe crash.
Christoph July 3, 2015 at 9:06am

I had a look at the log file. Although I am no expert it looks strange to me.

If I read it correctly the log shows a crash error already before you took off. I don't know how the crash error is triggered? By tough accelerations? Did you do anything before take off or before your real flight? Drop it onto the ground? The current drawn from the battery goes steep up.

Log also shows that you raised your throttle to max at that time.
- Christoph > Christoph July 3, 2015 at 9:11am
  
  You roll angle also changed a lot. Did your IRIS fail to take off and tipped over?
- Mhct > Christoph July 4, 2015 at 12:21pm
  
  Thanks for taking the time to look Christoph.
  
  You are right concerning the tip over. I forgot to mention that int he post. The first time I tried to fly it tipped over.
  
  As another update. I changed the broken arm and did another test flight. Everything worked flawlessly, what is even more strange for me.