300km

Auto takeoff and crash x2

Can anyone help me find the cause of the only two crashes I've had with my FPV Raptor and APM 2.5.

I've done a dozen or so auto take offs successfully, but two of them resulted in crashes. Actually in both cases I recognized things weren't going well and tried to switch to manual to save it, the crash happened once I was out of Auto mode. The crashes were on separate days with successful auto takeoffs between times.

In both cases the plane got off the ground then headed in the wrong direction. I'll just talk about the one that I have logs for. It got up to about 10m of altitude (WP2 was at 20) then stayed around 10m and headed in the wrong direction. In the second image 99.6 or after point 1:26 in the video you can see that the Current Heading (red line), Intended Heading (green line), GPS Reported Direction (black line) and Direct Line to Next Waypoint (yellow line) are all over the show. I left it for a bit hoping it would reach 20m then head for WP2 but it lost a few meters, in a panic I tried to switch to manual to save it but got RTL and it hit the ground.  

Now that I've looked at the logs I see that even the "successful" auto take offs earlier in the day had the various heading indicators all pointing in different directions, but those flights all got to the altitude of 20m and did a half reasonable job of following the WP course and auto landing.

The video is of the last successful flight (auto take off, circuit and auto landing), then the unsuccessful flight (auto take off and crash).

The images are 82.48.jpg below showing the wobbly successful flight, 

3690983845?profile=original

and 99.6.jpg showing the plane on the way to its doom.

3690983965?profile=original

Log file attached. Several successful auto flights including the last few at 58% 79%

Crash flight starts at 98.7

I had one previous exciting incident which was somewhat, but not completely, solved and may be related. See http://diydrones.com/xn/detail/705844:Topic:1034997

From that I learned that magnetic offset exists. I've attached an image of the magnetic offset trace from one of the flights magoffset.gif. Should it change so much during flight?

3690984016?profile=original

 

2012-12-13 06-18-04.tlog

2012-12-13 06-18-04.param

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Replies

  • Hi, I once saw something similar (plane flying sideways on map) when the compass was being distorted by the magnetic field of my 40 or so amperes motor wiring.

    Have you tested if there is interference? I don't know about the offset values, I just mean does the compass shift when applying throttle? One needs to check in several different directions, because with a single test, one might just happen to choose the single direction where the magnetic fields are aligned and nothing is observed.

    How far is the ESC wiring from the APM, and are the + and - wires in the high current circuit far apart? They should run closely parallel, or even better twisted.

    Regards

    Soren

  • 300km

    Anyone?

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