I have added a Lidar laser scanner sensor to my quad (uses Pixhawk - APMcopter 3.4.0 [last developer version] ). it was flying fine for first 3 minutes (from fine I mean I was in altitude hold mode and it was trying to keep the altitude, however it wasn’t that stable [you can see in the log file]). Anyway, suddenly buzzer started beeping and I figured out it is in the fail safe mode now and I was expecting it to land ( I had set it so that it should land for battery low fail safe) BUT instead of landing it started going up !!! and no matter how hard I tried to bring the throttle down and make it land it just kept going up and eventually crashed to the ceiling of the gym in over 30 ft and crashed down to the earth
I reviewed the log, apparently every thing was working fine (lidar was telling right altitude also barometer was showing increasing the altitude I am not sure what had happened. There was one wired thing ALT parameter in CTUN category in going down!
Please help me understand what happened and what was the cause this strange behavior. The other question is how can I make pixhawk pick ONLY the altitude given by Lidar and not anything else?
As it’s the 3.4dev version and not a release version, it may have some unexpected bugs in it.
The only thing that I can see from your log is that your battery is woefully inadequate if your voltage reading is accurate.
It drops from 12.2v to 8.5v just on take off, settling in to 9.3v within the first minute.
[quote=“MarkM”]As it’s the 3.4dev version and not a release version, it may have some unexpected bugs in it.
The only thing that I can see from your log is that your battery is woefully inadequate if your voltage reading is accurate.
It drops from 12.2v to 8.5v just on take off, settling in to 9.3v within the first minute.[/quote]
It’s been my experience that the power module included with the Pixhawk (and others also) ready incredibly low on load. I’ve experienced this in 4S and 6S batteries. I’ve calibrated voltage reading as well as amperageg draw using the indicated methods. I have a FRSky Lipo meter that sends back voltage data to my radio which I can log. The PX power module ALWAYS reads low when I’m loading the copter. Even in a hover it still reads low. The only time it ever reads anywhere close to what the telemetry from the Lipo module is returning is after landing. I’ve tried the stock Pixhawk power module, an Attopilot module (of which I did all the necessary recalibrations) and I now have an Andoer 6S module that I picked up on Amazon. They ALL do this. I’m not sure quite why, but I don’t trust the power readings that the Pixhawk gives me aside from resting voltage.
