Having fun with 2.0.23 - sofar seems stable on stock AC frame with sonar. I am not having luck with default PID for sonar (log included). As soon as I hit alt hold it will sink, but occasionally rise. This is a typical log at the default .35 .05 .3 settings.  I have played with these, seems like .45 .07 .3 gets closer to staying at altitude, sometimes a minute or two, but still can drop or shoot up for no apparent reason. I am running out of PID settings to try, never seem to hone in on stability. Sonar works fine with NG, and log seems to show correct distances for this flight. I have flicked ch7 off/ on while hovering, while hovering with alt hold, and even left it on to no apparant effect. Very strange......

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Which sonar sensor are you using? We default to the XL MaxSonar EX0.

I am using XL Maxsonar EZ4 - do I need to change?  One more clue - here is a log I ran flying with pid at .4  .07 .3 - unit stayed at altitude about 1 meter for a minute or two - much better than default pid of .35 .05 .3.  However, as you can see it decided to come to earth quickly for no apparent reason. Am I better off just changing sensor or is this a pid issue?  I am still puzzled on the ch7 function - It would be incredible if we could just hold alt by flipping this switch like the old NG code - altitude hold in simple mode would be very hot. Is it not possible to do alt hold in simple mode?

Maxsonar web does not list EX0  - do you mean EZ0 (wider beam version of EZ4)?


I was having pretty good luck with my new sonar installation, using the EZ0 unit. Got a few flights in with it holding very well in sonar, zooming up and down the field at low altitude, however at the end of the runs, it would rise up a bit when I slowed down to revers course and when it rose up, past 4 meters, it just kept going up. It did this regularly. If I kept it slow, the the quad did not rise up as much and alt hold in sonar worked fine. But with some speed and the inevitable rise as I stopped the quad and reversed course, it would lose its lock and just keep going up at a steady (slow) rate until I took it off alt hold.


My last run, alt hold off, I was speeding down the field about 2m altitude when it just dove over into the grass. It appears either the aft motor died, or a prop blade came off and then it just went right over. Some damage, one motor inop, but I think it's one of the wires, also could have been the reason for the in-flight shutdown.


Can you guys tell what happened by looking at the attached log?





Saw the last name and had to say Hi...lol...

Fast Crash from Jim Phoenix on Vimeo.

Here's a video showing the sonar altitude hold disengaging at the end of a run, it just climbs up, then I disengage, fly around a bit, then it dives for the ground. My wife is laughing at the beginning of the film, because I had just crashed it before this flight and we were surprised that it came through unscathed, and were kinda laughing about it. Not so lucky this time :-( but easily repairable.


Looking at the HD raw video frame by frame of the crash, there appears to be nothing wrong with the motors or props, just pitches right over into the ground - might be a depleted battery, I'm still waiting for my battery monitor to arrive in the UPS - this is another lesseon learned.





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