Governor Tuning¶
The goal: a steady headspeed through any manoeuvre, without surging or hunting. Ideally the precompensation (feedforward) does most of the work -- adding throttle before the headspeed sags -- with P making quick corrections and I holding the headspeed over time.
You need the governor set up and working first -- see Governor Setup. The gains are per profile, on the Profiles tab.
A governor can be too good
A well-tuned governor delivers a lot of torque, and the tail has to counter all of it. If the tail can't hold during hard collective, the answer may be a softer governor, less collective, or more tail authority (bigger tail blades, a higher tail ratio) -- not more tail gain.
Preparation¶
- Motorised tail: set TTA gain to 0 while tuning the governor.
- On the Blackbox tab, log at 1 kHz with
the Governor field on, and Debug mode
GOVERNORfor extra detail. - Change one gain at a time. With the Lua suite you can change gains at the field between flights; an efficient routine is to fly three or four values around the default for one gain, logging each, then compare.
The test manoeuvre: hard pitch pumps -- full positive, full negative, repeated -- and fast climb-outs. Look at the headspeed trace in the log.
1. Collective precompensation and F¶
Collective precomp (default 50) adds throttle as collective rises; the Feedforward Gain (default 10) scales all the precompensation together.
- Headspeed drops on each pump: raise collective precomp (or F).
- Headspeed rises above target on each pump: lower it.
Try steps of about 10. Then tune Cyclic and Yaw precomp the same way, with hard cyclic and pirouettes.
2. I-gain¶
Raise I (default 50) until a slow oscillation in headspeed appears -- during or after the pumps -- then reduce it by about a third. Steps of about 25.
3. P-gain¶
Raise P (default 40) until fast oscillations appear, then reduce it by about a third. Steps of about 10.
If the headspeed surges or hunts overall, Master Gain (default 40) scales P, I and D together.
4. D-gain¶
Usually not needed. Larger helicopters, with heavy rotors, may benefit from a little.
Symptoms¶
| You see | Try |
|---|---|
| Headspeed sags on collective, recovers slowly | Raise collective precomp / F, then I |
| Headspeed overshoots after a pump | Lower precomp, or lower P |
| Slow headspeed wander, ~1 Hz | Lower I |
| Fast headspeed oscillation, audible surging | Lower P or Master Gain |
| Throttle near 100% in a hover | Headspeed too high for the power system -- lower it or change gearing |
| Motor bogs, then overspeeds in descents | Turn on Dynamic Minimum Throttle |
| Pack sag makes headspeed fall late in the flight | Turn on Voltage Compensation (needs Battery ADC) |