Uncommanded Land Mode Desired Position Bias

🧪 Flight Testing & Log Analysis
1

Hi all,

I’ve noticed what appears to be a desired position bias when entering land mode during flight that I cannot explain. The following is a previous flight where I experienced this behavior:

position_x_1.png844×337 25.6 KB

As you can see by the Position X plot above, when I switch from Position (green) to Land (purple), the position clamps to, what seems like, an arbitrary bias. I was able to repeat this behavior in a subsequent flight:
position_x.png844×337 23.2 KB

This seemingly arbitrary offset is also found in the Y axis. Here are links the two flights’ logs: Land Bias Flight 1 Land Bias Flight 2.

More notes on the flight tests:

  • Both flights tests were completed after power cycles
  • This behavior is occurring about 1 out of 4 times I power cycle
  • I am currently branched off of v1.6.5 my branch has minor mavlink additions unrelated to the commander source.

Has anyone experienced behavior like this before? Any tips on how to replicate this behavior regularly?

2

I’m not sure, but before spending too much time debugging this I recommend you try the latest master, which will soon become v1.7.0. There have been a lot of changes to the multicopter position controller.

3

@dagar thanks, I will give v1.7 a try. I’ll report back after I test.

FYI, I was able to repeat the results in an HIL sim. It appears that when I toggle land, the controller sets the XY setpoints to the home position.

4

@dagar Good news, I rebased my changes on top of v1.7rc0 and I haven’t experienced/been able to replicate the land issue :+1:

Thanks for your help! I’ll continue working off of the 1.7 rc’s and tell you guys if I experience any abnormalities.