Ran into a bug on our physical plane where failsafe.last_valid_rc_ms was not recognizing that the transmitter had failed. This is likely due to how the standard failsafe works in receiving lower-than-possible throttle values. So in order to account for this, I added a new variable to the failsafe, AFS_last_valid_rc_ms, and I update it only if the ch3_failsafe (the throttle failsafe) is not on. If the throttle failsafe is on, that means that the plane has indeed lost transmitter input, so the AFS needs to recognize that.
Reverse thrust for controlled landings, even with much steeper approach slopes. This is achieved by allowing throttle demand to go negative to maintain a target airspeed. A Pre-Flare stage was added, triggered by an altitude, to allow for a slower airspeed just before land. That lower airspeed can be near stall.
new params LAND_PF_ALT, LAND_PF_SEC, LAND_PF_ARSPD, USE_REV_THRUST
The PSTR is already define as a NOP for all supported platforms. It's
only needed for AVR so here we remove all the uses throughout the
codebase.
This was automated with a simple python script so it also converts
places which spans to multiple lines, removing the matching parentheses.
AVR-specific places were not changed.