until now the desired thrust was simply the absolute value of the thrust setpoint vector
but a multicopter is only capable of producing thrust in its (negative) body z axis
this leads to excess thrust during attitude tracking errors
one important use case is:
trying to land with minimal thrust in NED z axis against gravity
but the position controller still correcting some small horizontal estimation errors
then this prevents unwanted thrust in a completely wrong direction
Matthias Grob
5f3cbbbbc2