AC3.1.3 Error when RTL or Automission Invoke land

Hello Arducopter Droners,

I experimented arducopter since version 2.6.

Now I’m using pixhawk with v3.1.3 firmware on Hexarotor.

Since I updated to V3.1.3 from 3.1.2, automatic land is not working properly when it’s automatically engaged in a auto mission mode or when the RTL mode engages the landing phase.

Infact, drone goes down normally, then it stabilizes at 10 meters above the ground and not move, while the RTL_ALT_FINAL parameter is 0.

Fortunately, I finished the landing by taking the hand in manual mode.

You will find attached the log of the last flight where I am testing different automatic landings.

Any thoughts are greatly appreciated.

I was browsing the forum at lunch and found this post. I have having the exact same problem since moving to 3.1.3 on both my quadcopter and tricopter. It comes down normally to around 7-10 meters and just sits there hovering infinitely until I take over and land it. Odd thing is that sometimes it will pause and land as it normally should. It is about a 50/50 chance every time.

Interesting note: if it is below this 7-10 meter threshold, it will land as normal every time. Does yours?

In the next couple of days I’m going to install my sonar to see if that help identify the problem. I’m guessing that the APM (in your case the Pixhawk) is checking for an event that is missing before making the final descent?

Custom Quad/ Custom Tricopter
APM 2.6, 3.1.3
sonar not installed at the moment

I’m glad to finally find someone who has the same problem!

In fact I have also noticed that below a certain threshold height (7-10 meters) it this pause about 50 seconds and finally began the final descent to the touchdown.

someone else has seen the same issue?

Randy and experts can give us some answers?

This problem is interesting at time when all developers working on AC3.2 release.

Is that this issue is already solved it for future version?

I saw a similar if not the same issue in the previous firmware version. See here: viewtopic.php?f=25&t=6843

Someone in that post made the comment:
“I’m wondering if this problems is actually that the Loiter performance is a bit loose, and the WP Radius is small. I’m not sure about Land mode, but I know this has caused me problems on RTL. It wants to make sure you hit the RTL waypoint precisely before it begins the land. And if it’s moving around a bit, it won’t be satisfied, and will keep trying to get that target point. This causes an non-deterministic delay on the RTL landing.”

Maybe that’s what you are seeing. My “workaround” was to fly at 9.9 m or below, which isn’t really a great longterm fix. :slight_smile: