Hi, this is my first post here and maybe someone can help me out.
When i go full tilt forward with my quad it looses power and tips over after about 3 seconds of good speed, it looks like APM shuts down for one moment.
After about 2 seconds it recovers and stabilizes again.
Here is my setup: apm2.6(not mini), 250 H-Frame, 80deg. max lean angle, motors 2300kv, 20A ESCs, GPS
In the logs i can see high vibrations on AccZ right before the problem occures. Well, i have used two layers of moon gel and thought this would do the trick but nothing.
The problem persists when i lower the max lean angle to 70deg.
I am struggling with this copter for 8 weeks now, please help!
Best Regards, Harald.
Replies
Thanks for the help so far...
i am away for work now for two days and will try to work on the tilt angle when i get back.
Also, the logs i uploaded indicate very strong vibrations on the Z axis at a higher speed. I will also try to dampen that even more.
OK, I tried 60deg max angle an it seems to help. It still is all over the place when braking hard at 80km/h but at least it looks like it stopped cutting the motors.
Not sure what's your configuration, but since the APM will try to compansate throttle for the leaning, 70 degrees of leaning would mean around 3 times of level hovering thrust ( 1/cos(70deg) ).
If any of your ESC maxed out, it'll cause controller unable to balance the vehicle, that might cause some problem.
I have no clues about your APM shuts down if that's true. It depands on how you power your APM. I'll guess that maybe your battery could handle the current and the voltage drops suddenly?
The logs show constant voltageinput for the APM.
Then it is unlikely to be an black out/ brown out event. But the lack of the power to ESC is still possible. I would simply guess it not enough power from the battery, or the 20A limits of your ESC has been reached. You can make a static test to see how much thrust you can produce with maximum throttle, if it's less then 3 times the weight of your quad, lower your lean limit.
I can check how much current is drawn on full throttle. Could that tell something about overloading the ESCs?
Yes, you can do that by seeing if you can measure at least 20A at full throttle. If it's significatnly less than that, it probably means your battery cannot output 80A of current (or you have a really low quality ESCs like I do).
However, my point is, even the battery can handle the current, the ESC working at maximum ampere, and you have good motors and props, the problem of not able to reach 70deg is still likely to persist because the maximum thrust simply cannot reach that high.
As I stated before, theorectilly you would need at least 3x the thrust of weight to achieve balance at that angle, and in reality, I would say you'll need at least 3.3x (10% higher) of weight for the controller to function. If that's not the case, lower your angle limit or install something more powerful.