i have configured following setting on my copter 4.1.2 RC Failsafe’s
FS_THR_FAILSAFE = 1
FS_THR_VALVE = 975
FS_OPTIONS = 13
FS_GCS_ENABLE = 1
i took off copter in GUIDED mode using MP at some height and proceed to the waypoint that i already planned and end of waypoint RTL was the command . through out this machine i never turned on my RC transmitter since my FS_OPTIONS = 13. so there is no required of Rc transmitter and that kept standby for the emergency purpose only.(ARMING _CHECK = 1) No bypass of arming check.
copter finished all waypoint and came back to home and start descend while i just turned on my RC transmitter at the movement immediately FC changed to RC transmitter current switch mode from Auto mode. This is normal ?
if So the way it should not be. Because if accidentally turned on Rc transmitter with Zero THR value May definitely cause Flight crash.
what my suggestion is that what ever the Auto controlled mode the copter is flying if we switch on the rc transmitter in between the flight controller should stay at current flight mode until/unless manual change from the rc transmitter with THR stick centered.
Auto mode most of the time no use of Rc transmitter so that time we switch off rc transmitter .when required that time we switched on but when switch on mode changed to Rc transmitter this should not happen.
Do you have specific idea to over come this issue?
Yes, when you turn on the transmitter, receiver is starting to give new pwm values from tranmistter to the autopilot. I guess one of them is set to mode changing via FLTMODE_CH. So probably this was leaved in a PWM value that corresponds to manually or semi-autonomous controlled throttle mode (STABILIZE, ALT_HOLD, LOITER). Autopilot obeyed to the RC transmitter and changed the mode because you requested it to do so.
Why would you do that? At least open the transmitter with mode switch corresponding to AUTO mode. If you really want to do fully autonomous flight, why you’re keeping the receiver on the vehicle? Or at least you can do FLTMODE_CH=0 which disables it.
I suggest you to leave mode changing switch in AUTO on you transmitter, this way even if you turn off & on the transmitter, if first bit of FS_OPTIONS is set (the one after the zeroth ), vehicle will continue in AUTO mode.
In autonomous flight, I always leave the throttle at %50, and mode switch in AUTO. Because sometimes transmitter might be on again off again during far flights.
always start with the transmitter on in case you need to grab it and take control. Unless you test extensively there’s probably going to be unexpected reactions when you turn on a TX mid-flight.
If the transmitter fails for any reason, leave it off and use the GCS to RTL. (see point 1)
Make your throttle stick spring-centred and set PILOT_THR_BHV,7
We see plenty of cases where people didnt understand some behaviour, like when the copter switched to RTL for some reason, then the person switches to Stabilise mode with the throttle at zero and then they aren’t quick enough to catch the fall.
Unless you are using a transmitter 100% of the time and fully away of stick and switch positions, it makes sense for a multirotor to use a spring-centred throttle.