On Aug 3 I was testing the droid planner 2 in auto mode and crashed my pixhawk quad. This was my 20th flight using the quad. Can anybody help me understand what caused this by looking at the attached log file?
In a nutshell I was flying loiter mode at about 100 feet agl. I switched to auto mode expecting the quad to fly a small circle. When I went to auto mode the quad started flying away but sounded as if the engines were surging and fighting. I immediately went into stabilize mode but was not able to regain control.
I was monitoring the quad on a nexus 7 and saw the battery voltage drop to 10.0 V.
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lowest logged voltage is 9.23volt, it was falling to the ground soon after at about 10v. the ThrOut shows that it tried to maintain altitude.
The prolonged time with instability may have been caused by the ESC's - IF they have a soft-shutdown featrure.
Roll was less stable than pitch (a small suspicion of hardware failure), but I still doubt your setup and PIDs are good at such low voltages.
also, stability got worse below 10.8 volts.
Can you tell me how to look at the log? I opened the file but was not able to get a handle on what happened.
I am using turnigy esc's. How can I tell if they have been damaged? I am trying to decide if I should replace the esc's on the machine?
Thank you for helping me with this. It is always good to confirm suspicions.
open Log (APM Planner 2 , or MP) - , and graph this;
CURR.Volt - (battery voltage)
ATT.DesRoll (desired roll angle)
ATT.Roll (actual roll angle)
you can see how Roll follows DesRoll worse as voltage drops.
As you for ESC's - it's hard to say , one way to tell is see if there is any sign of physical damage, another to hook up to a motor (no prop) - run it on low rpm, and gently press/twist the ESC's PCB)- if any pins/pads (SMD coldered contact surfaces) are loose - you'll most likely see the results then (anything from uneven run, to magic smoke) - always better than getting that effect midair.