Hello,
When flying heli, in case of requesting to much ground speed, or too much climb rate in automode, there no security…
we can go over engine max power and issue rpm drop that conduct to crash.
How to activate rpm check and automaticaly limit collective in case of rpm drop over limit?
I’m trying to do so with lua, but I think that this can be interesting feature.
We can also check EGT, if EGT goes over x degrees, we can activate collective limiter.
Hello @bnsgeyer,
What you advice regarding collective limitation?
I can make lua that check RPM and limit PSC_ACCZ_IMAX dynamicaly if I loos to much RPM?
What do you advice?
Limiting the Z integrator will cause loss of altitude and likely no further corrective action ex. reduction in demanded velocity.
I would advice against this. In critical situations, you want the ability to go over limit and while low RRPM is almost never good, it’s better than the alternative.
Better idea is to warn the operator and let him take appropriate action(s).
Messing with inner loops is definitely a bad idea. Limiting outer loop demands IMHO is reasonable way of protecting against inadequately set parameters ex. due to increased mass or drag. Copter and heli already lean back if they can’t maintain altitude. Adding low RPM/high EGT would benefit protect users and equipment. Low RPM if not corrected will likely lead to collapse as drag induced at required blade AoA increases and high EGT will lead to motor failure. IMHO heli would benefit from some sort of TECS equivalent.
Hello,
@implicit You are right.
The best is to warn the user and let hime take appropiate action.
Yes if there is some TECS equivalent to heli would be fine.
For example limit attitude ground speed in case of egt or rotor low speed limit.
Also I make test on simulator, Ardupiilot limit attitude when integrator is on llimit.
There is the issue that the user may not be available to take action (ex. RC control & GCS failsafe, one way link etc.)
In that case, how would you know if it isn’t doing it to say, avoid terrain? Deal with icing? If you are reducing pitch , you will lose altitude, but with a loss of C&C, you have no way of knowing what the situation is.
The idea is that the autopilot should take sensible action (slow down to V Min power) im absence of operator input.