Pixhawk 2/PX4: Trigger flight termination on digital input?

Hi Everyone,

We are currently trying to integrate a parachtue (DRS-10) with our Pixhawk 2 (running PX4), and in addition to two other issues (one and two), we have the following question.

The parachute we are using provides an own IMU and can trigger itself when certain conditions are met. This is meant as an additional redundancy in case the flight controller fails entirels. It fires when roll/pitch limits are exceeded, or free fall is detected.

When the chute fires, however, we would like the Pixhawk to go intro flight termination mode. This is to prevent to motors from spinning and avoid them cutting through the parachute lines.

We realize that if the flight controller has failed entirely, this will not work because it will no longer be able to go into flight termination mode. However, in case the chute fires and Pixhawk has not failed entiely, it is still crucial to kill the motors.

Our parachute can provide either a PWM high/low signal to determine whether it has fired, or a constant DC high/low. Is it possible to configure the Pixhawk in a way that it enters flight termination mode on one of those triggers (PWM high or DC high)?

Thanks!

Best,
Michael

Hi @michael-borkowski ,

Currently, the only ways to trigger flight termination is by internal automatic triggers (geofence, RC loss, DL loss, FailureDetector, …) or the MAVLink message VEHICLE_CMD_DO_FLIGHTTERMINATION. It’s unfortunately not possible yet to configure it to react on the state of a pin or from RC.

Those things would obviously good to have so if you can implement them, just ping me and I can review your PR (hint: the flag you need to set to true is force_failsafe in the actuator_armed message, here is an example of how termination is triggered by the FailureDetector).

Enjoy flying!
Mathieu