Collective jerk when disarming after land

[ChrisOlson]

@Rob_Lefebvre

The kick occurs immediately as I switch off the Interlock.

Yep, same here. But it will happen on a auto-disarm too.

@Rob_Lefebvre

I suspect it’s a bug that crept in with Leonard refactored the “spool logic” but I don’t know.

I don’t think so. We’re still working on that. We did heli and we’re waiting for Randy and Leonard to go thru their part of it, then me and Bill and are going to finish the spool logic for heli. But we started that a long time ago, and now Randy is having problems rebasing it on the latest master. We’ll test it when it get to PR status, but I don’t think the problem is in the spool logic.

@Rob_Lefebvre

It really shouldn’t do that regardless of GPS glitch. At least it didn’t used to. Used to be that it would “guess” when it’s on the ground, and would not chase a GPS glitch around like that. So I don’t know what’s going on in your case. Either your settings don’t allow it to guess that it’s disarmed. Or it is something changed in the code.

No, it shouldn’t do that. I’m still working on it and getting some info together for Paul R. I think we got a EKF issue. That was with 3.6-rc1.

Paul is the expert on this. But I think it’s a problem with how the GPS is fused into the EKF. A glitch doesn’t necessarily get “chased”. It means the GPS has become unreliable and the system actually does a very excellent check of that and detects an unreliable GPS every single time. I have been able to duplicate it in safe conditions with 100% success. The problem is in how the system deals with it in determining the alternative attitude solution. Paul will get it sorted out, and it’s not noticeable with a multi in spool-down like that, as they have no more thrust authority after shutting down. So I’m still working on it to get Paul the info he needs to fix it.

[Implicit (Jakob Schmidt)]

I land in loiter or auto the majority of the time and have never seen this. Anecdotal, I know. This is on 500/600 sized helis.

[carlosanlley (Carlos Sanlley)]

@Implicit

I land in loiter or auto the majority of the time and have never seen this. Anecdotal, I know. This is on 500/600 sized helis.

can you share your aircraft parameters?

[bnsgeyer (Bill Geyer)]

I reproduced this issue in SITL. And made an issue in github Here. I posted a log from my test. I went thru the code but still can’t figure out what is causing this. I’ve asked Randy and Leonard to look at it.

[bnsgeyer (Bill Geyer)]

So I did a little more digging and found the problem. It was a logic issue where switching motor interlock to disable before the land_complete flag was set caused the state of the aircraft to go from flying to motors stopped. Normally if the motor interlock is disabled after land_complete then the aircraft goes into the landed state before motors stopped.
So this should be an easy fix in the interim but I want to talk with @Leonardthall about some difference between multi and heli in how the altitude controller is programmed with the motors stopped. Heli has a descent commanded where multi just relaxes the altitude controller.