Hi
So today when I went to disarm my apm 2.5 it entered RTL mode and my quad suddenly took off. I had control of roll and pitch but not throttle. The quad shot up about 30 metres. After fighting with it I eventually crashed it through a tree which brought it down.
Anyway, I have since been able to repeat what has happened. It turns out that when I have a low transmitter signal and go to disarm the system it enters RTL. It stays in this mode even if I regain a strong signal. I can only get it to exit this mode when the receiver is turned off then back on.
Anyone got any ideas why this would happen?
I have failsafe set on both the receiver and the APM.
(Failsafe on receiver changes channel five flight mode to RTL.)
Could this be the problem?
However, if I turn the receiver off it enters the APM failsafe. As soon as I turn the receiver back on I have full control again.
That's why I don't understand why the system gets stuck in RTL even when I have a good signal strength.
I am running Ardupilot V2.8.1
Michael
Replies
I did experience the same happening for me today.
This was with Turnigy 9X with ER9X firmware and FrSky transmittermodule and receiver.
Maybe you did have the same problem?
While looking at Radio input in configuration setup in Mission Planner I watched the Throttle channel.
When applying full rudder left for disarming my throttle channel dropped to below my failsafe value.
I did test APM by using servotester directly to rudder input and the throttle didn't drop. Only when rudder connected to the radio. I concluded with this being a problem with radio/transmitter combination and solved it by decrease travel for rudder in traveladjust at the transmitter. Below the point where throttle is affected and recalibrated radio in APM. I could possible also moved throttle to another channel number.
This problem was with throttle connected to channel 3 and Rudder connected to Channel 4.
Low Throttle 1005, failsafe 988, failsafe set point 995.
Combination of low channel 3 (1005) and using full left on channel 4 gave 988 output on channel 3.
If you have failsafe enabled on your APM it will look for low throttle (below 975pwm) to enable it. If you run failsafe on your radio using CH5 you don't need to run the throttle based failsafe.
You can run the CLI test to see what your radio outputs, but I'm guessing from the description it outputs below the failsafe trigger.
My advice would be do turn off failsafe on the APM and just use your radio.
Also the APM will disarm automatically after ten seconds with no throttle.
Jason