Hi,
I wonder if if would be hard to add a reliable crash detector to APM? Something that detects that the aircraft is stuck in the terrain or a tree or whatever. It would be nice to have, as it would enable shutting down the motors, preventing them from burning out and there might even be a chance of saving the battery.
Any good ideas on how? I had thought of:
- Stabilization I terms: If I terms in attitude stabilization have nozero factors and reach high values over long time (their limits, for example) it is indicative that the aircraft is not under control. Problems: It could also just be bad PID config, and anyway most people fly with zero I factors and/or limits.
- No rotation: Gyros have near-zero readings over some time. Problems: They also have that in a very well stabilized aircraft, and an aircraft in a tree or with a damaged prop may still move after a crash
- No GPS movement. Requires that there is a GPS. It is safe to regard a long time without a lock as a crash? A hovering aircraft also does (almost) not change position.
- Consistent constant non vertical acceleration over some time. There are the obvoius problems of long forward flight (copter) and long steep climbs and descents and circle patterns (plane) but maybe that can be solved.
- Combination of the above.
Did someone find a good solution already?
Regards
Soren
Replies
Hello Søren,
we have accelerometers on the APM board, I think it is enough to read a peak higher than a certain value of "G" to establish that the aircraft collided with an obstacle or the ground.
Of course is important to filter well the reading of the accelerometers to avoid false collisions.
A certain information however you can have only with the sum of two readings, one may be a high peak of "G" added for example to the GPS reading that no longer detecting any movement.
Regards,
Fausto