Our drone started to land after experiencing a number of RC/ GCS failsafe but there is no landing on any of its failsafe setting as far as I know.
It was using LTE datalink and joystick was attached to GCS laptop at the time. GCS failsafe was set to RTL so was RC failsafe. Final action of RTL was to hover at 30m.
This incident happened when the copter just took off of the ground and lost its connection to GCS linked via LTE datalink. We tried to take control back using in vain and it began its RTL process but began to land all of sudden.
Upon what I found on the list of parameters, copter can start landing when it has GPS issue while RTLing or EKF failsafe which is not really familiar with me.
Analyzing log didn’t go well without revealing any clue of its unexpected behavior of landing.
Have you tested RTL before?
You have RTL_ALT_FINAL,3000 (30m) but the parameters list 1000 (10m) as the maximum - actually I just checked in the code and didnt see where this would be an issue, but keep it in mind.
What I did find was this:
case SubMode::LOITER_AT_HOME:
if (rtl_path.land || copter.failsafe.radio) {
land_start();
} else {
descent_start();
}
It means if there is a radio failsafe then the copter will Land as part of RTL instead of just descending to the RTL_ALT_FINAL
And you have many radio failsafes, along with the option to “continue landing” if any other failsafe occurs.
You would need to have a solid radio signal and change into another flight mode, like you were trying to, in order to prevent the Land.
Thanks for kindly taking time to look into my trouble.
Yes, I’ve done RTL several times and it all finalized at 30m above homepoint. Even the parameter limits the maximum altitude at 10m on the description, it allows us to set it up at 30m and it does so when RTLed.
What confuses me now is that parameter FS_THR_ENABLE is set as of 1, enabled always RTL, but copter somehow decided to land denying the parameter. I do recognize having set the FS_OPTIONS to continue landing on any failsafe.
Since we’re operating at remote island so occassional disconnection from GCS is not completely avoidable.
A radio failsafe is a special case and RTL will ignore the RTL_ALT_FINAL and just Land.
You may have to adjust your timeout values.
Some RC systems rely on the the throttle channel PWM going below a certain value to mean signal loss, and newer protocols like SBUS dont rely on that, instead there are flags within the protocol.
But either way, a signal loss is an RC Failsafe and it’s going to initiate an RTL with Land.