Copter crash in RTL mode

rrr6399 · February 27, 2018, 10:11pm

If FS_THR_ENABLE is enabled, it will FS when no R/C is detected.

If you have an R/C connected and the telemetry fails and you’re not in guided mode, the telemetry fail safe will not activate since there is an assumption that the R/C can be used to control the bird.

Here is the logic:

github.com

ArduPilot/ardupilot/blob/master/ArduCopter/events.cpp#L83


// set the low battery flag
set_failsafe_battery(true);


// warn the ground station and log to dataflash
gcs().send_text(MAV_SEVERITY_WARNING,"Low battery");
Log_Write_Error(ERROR_SUBSYSTEM_FAILSAFE_BATT, ERROR_CODE_FAILSAFE_OCCURRED);


}


// failsafe_gcs_check - check for ground station failsafe
void Copter::failsafe_gcs_check()
{
uint32_t last_gcs_update_ms;


// return immediately if gcs failsafe is disabled, gcs has never been connected or we are not overriding rc controls from the gcs and we are not in guided mode
// this also checks to see if we have a GCS failsafe active, if we do, then must continue to process the logic for recovery from this state.
if ((!failsafe.gcs)&&(g.failsafe_gcs == FS_GCS_DISABLED || failsafe.last_heartbeat_ms == 0 || (!failsafe.rc_override_active && control_mode != GUIDED))) {
    return;
}


// calc time since last gcs update

There is still an assumption that there is always an R/C, which may not be the case these days. There probably needs to be a discussion with the ardupilot team to flesh out all the edge conditions.