Flyaway and white indicator

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Kornel
Posts: 1
Joined: Sun Feb 12, 2017 12:55 pm

Flyaway and white indicator

Post by Kornel » Sun Feb 12, 2017 2:31 pm

My Xiro V rear indicators start to flash white and the drone flies away. I cannot control with remote, only up and down (so I make forced crash landing with the drifting drone - good we have deep snow today..). I cannot find the explanation of white slow flashing indicator anywhere in the manual. Anyone can help me what this is? This now happened third time in a row, quite randomly. Then I try to fly the drone again, no problem. I dont dare to fly it anymore near sea or pond, as never know when it will drift away.. Any help appreciated...

vsc
Posts: 4
Joined: Tue May 30, 2017 2:35 am

Re: Flyaway and white indicator

Post by vsc » Tue May 30, 2017 2:50 am

The same thing occurred today on my Xiro Explorer V, though I had a G gimbal fitted at the time. I was flying for some time, using the autopilot to fly a circle. When exiting from that mode the drone started to drift and I put in lateral stick to correct. That said the drift increased until I no longer had sufficient authority to compensate and was forced to drop the drone to the ground. In the end a reasonably soft landing but it did roll over onto the props. Thankfully on grass.

My sense is that the compass calibration wasn't good before takeoff. In fact the sequence of events was I took off without recalibrate for the local area and got a warning. Landed and calibrated but it complete quicker than usual.

Subsequently I recalibrate and noticed that it took a long time, which I find is normal for the Xiro. Finally another flight where I had no further issues.

I'm guessing a compass bias causes an error to build up in the flight control loops over time, especially if the aircraft is rotated. Eventually the bias is large enough to push the aircraft in some direction where control authority from the ground station is insufficient to overcome the bias.

It is a good thing that commanding a decent is possible. But this also proves why flying is a large field away from a tree line or the like is a very good idea such that one has room to manage a problem to a reasonable end of flight without catastrophic damage to the aircraft.

Edit:

After downloading the telemetry data from my phone and using the Xiro Assistant I determined that the magnetic and GPS headings were 100 degree different when this problem occurred. Notable is that earlier when circling the deviation sporadically occurred but the aircraft ignored the compass and with with the GPS coordinates.

Specifically when the aircraft came out of circle me and went into a hover the numbers deviated. Additionally, I found that at that juncture I put in compensation but in the wrong direction, enhancing the drift. In fact the telemetry shows I subsequently added full authority which increased the slip in the wrong direction. Pilot error? Clearly the compass was registering a large deviation from true North. My attempt to fix the problem made the situation worse, where I suspect if I went hands off it might have largely corrected itself.

That said it is also notable that 300 meters away were high voltage power lines on large towers. Did these power lines cause the compass to sporadically deviate? My sense is yes. Moving to an open location I was unable to reproduce the problem, where the post flight telemetry showed the compass issue did not reoccur.

On the other hand there is disturbing data points in the telemetry. Using a new battery, when the aircraft hit rough air (shown by the vibration parameter in the telemetry) the battery voltage dropped out, but recovered a few samples later. This was not known via visual observation of the aircraft, only the data. Additionally, there are periodic loss of GPS where the aircraft stays in GPS mode, versus attitude. It would appear that the aircraft's control laws are setting to coast through a short loss of GPS, which is a very good thing.

I very much appreciate the Xiro providing telemetry logging and their analysis tool.

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