What exactly is Q_VFWD_GAIN defined as?


I’m continuing to improve on my PZ Radian Pro quadplane installation. (Pixhawk 2.1, latest beta arduplane firmware, t-motor 4in1 esc, pretty standard stuff)
Overall I’m very impressed with Arduplane, autotune, q_autotune, Mission Planner, etc…

I have good position hold during loiter and I have smooth outbound and inbound transitions between FBWA and Q_Hover.

I’m experimenting more with increasing control in windy conditions in Q_Loiter. (The Radian has a relatively low wing loading so is susceptible to disturbances)

I’ve enabled Q_WVANE_GAIN and have pushed Q_VFWD_GAIN to 0.5 which is the maximum recommended. This seems to reduce ballooning (from changes in wing pitch/lift) when the aircraft is commanded fore or aft in Q_Loiter.

I have a few general questions regarding Q_VFWD_GAIN:

  1. What exactly is it defined as? I assume it is unit-less? Is it a fraction of propeller control versus pitch attitude control for fore/aft positioning?
  2. It looks like Q_VFWD_GAIN will accept a value of more than 0.5 and I plan to push it beyond slowly. I assume this is fine as long as I move cautiously?
  3. What exactly will happen if I push Q_VFWD_GAIN to 1.0? Is this the maximum number it can possibly be set to?


I decided to take a look at the source code.
Looks like Q_VFWD_GAIN is purely an integrator.

[// integrator as throttle percentage (-100 to 100)
vel_forward.integrator += fwd_vel_error * deltat * vel_forward.gain * 100;]


Question answered.
Time for more fly, less type.