Hi all,

I was wondering what would cause the Desired Altitude to jump in Alt Hold mode in Arducopter 3.3? I was flying my hexacopter in Alt Hold mode outside when I decided to try and fly under an outdoor overhang. I had the throttle mid stick to maintain altitude and as soon as it went under it started climbing and I could hear the motors start increasing throttle erratically. I was able to land it, but when I was looking at the data logs (Pixhawk BTW) I saw that the desired altitude had jumped randomly even though the throttle input had not changed. I was under the assumption that the throttle input
was the only thing controlling the desired altitude, but what else would cause this behavior (right before the 24000 mark on the x-axis)? I attached a picture of the graph corresponding to this behavior and the flight log. Thanks in advance.



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  • I looks like you need to calibrate he throttle stick and change your midpoint. Looking at that first data log, your desired altitude is changing with your throttle stick (Channel 3) when it is outside the deadband. Changes in Barametric Pressue should not change the desired altitude, just the current altitude.


  • hay.... I have this same issue with ac3.3.3. When I switch to altitude hold mode the quad suddenly drops with the throttle stick in the mid position. When I reviewed my log it shows, the desired altitude dropped  so the quad. I think it could be a barometer issue due to weather. I have attached some of the logs where altitude hold doesn't work..

     If you got any solution pls do share...... 

    2016-12-09 13-37-11.bin

    2016-12-08 15-16-40.bin

    2016-12-08 15-25-19.bin

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