A fail-safe or fail-secure device is one that, in the event of a specific type of failure, responds in a way that will cause no harm, or at least a minimum of harm, to other devices or danger to personnel.
Taking this definition as a start point, drones, obviously, also needs security measurements. You could configure Erle-Copter to enable failsafes. In this section, we will explain how to activate some of them (the most meaningful ones). For more info check this site.
Note: As user might not have GPS, this section will show how to setup failsafes using land mode
Erle-Copter supports Return-To-Launch/Land in cases where contact between the Pilot’s RC transmitter and the flight controller’s receiver is lost.
If enabled and set-up correctly the radio failsafe will trigger if:
Follow the next steps to enable it:
Make the next tests in order to verify is working fine:
Now turn off the RC and check that the value descends:
Switch to stabilize mode, arm your motors but keep your throttle at zero. Turn off your transmitter. The motors should disarm immediately (red led will start flashing, DISARMED will be displayed in the Mission Planner’s Flight Data screen).
Switch to stabilize mode, arm your motors and raise your throttle to the mid point. Turn off your transmitter. The Flight Mode should switch to LAND.
Notice that the value of the throttle is lower than the minimum value (~1053) when the RC is on and that Erle-Copter has changed to Land mode.
Erle-Copter supports the activation of Battery based failsafe. Our Power Module enables battery monitoring. Right now (19-03-2015), battery voltage reading is supported in the latest Autopilot. Download the latest binaries from our repository!
Thanks to this reading, the user could know the battery voltage using a GCS.
This failsafe permits to you to minimize the risks of having a sudden death of Erle-Copter and enables a better use of your LiPo batteries.
If enabled and set-up correctly the battery failsafe will trigger if battery voltage drops below the threshold voltage determined (10.5v by default).
Also notice that if you try to arm Erle-Copter having a lower battery voltage than the trigger threshold one, an low battery error will show up (in the GCS in case you are using it).
Note: The use of a voltage sensing Power Module is mandatory!
Note: We are working on having current measurement, this will be used to establish current based failsafe.
Once you have activated the failsafe, you could check that you cannot arm Erle-Copter. Follow the next steps:
Don't forget to restore desired low battery voltage value again!