Rudder Common Gain -- what is its purpose?

In case you do not know something or you are not sure, here is the right place for your question.
Post Reply
curmudgeon
Posts: 231
Joined: Thu 01. Oct 2015 15:13:29

I am pretty happy with the Spirit. I love the reliable rescue feature which has my back when I need it most. The Jeti integration makes it even more enjoyable for me.

I am now trying to fine tune. The governor needs a little fine tuning to keep the RPM a bit more consistent, and the tail kicks whenever I apply collective. I understand that this is a "trial and error" process.

When optimizing the rudder, when do I adjust the regular "Rudder Gain" vs the "Rudder Common Gain"?

As I try to figure this out, it seems to me that the Sensor >> "Rudder Gain" is just a pure P gain, the Advanced >> "Pirouette consistency" is a pure I gain, and the Advanced >> "Rudder dynamic" is the D gain. Assuming that I am correct and that all three PID values can be adjusted independently, what is the purpose of the "Rudder Common Gain" multiplier?
jgiannakas
Posts: 183
Joined: Sat 02. Jan 2016 12:17:50

curmudgeon wrote:I am pretty happy with the Spirit. I love the reliable rescue feature which has my back when I need it most. The Jeti integration makes it even more enjoyable for me.

I am now trying to fine tune. The governor needs a little fine tuning to keep the RPM a bit more consistent, and the tail kicks whenever I apply collective. I understand that this is a "trial and error" process.

When optimizing the rudder, when do I adjust the regular "Rudder Gain" vs the "Rudder Common Gain"?

As I try to figure this out, it seems to me that the Sensor >> "Rudder Gain" is just a pure P gain, the Advanced >> "Pirouette consistency" is a pure I gain, and the Advanced >> "Rudder dynamic" is the D gain. Assuming that I am correct and that all three PID values can be adjusted independently, what is the purpose of the "Rudder Common Gain" multiplier?
I've found that for larger helicopters or for super fast servos you end up maximising the rudder gain on the transmitter. Hence if you need to go higher you need to use the multiplier (rudder common gain) to give you more headroom to adjust gain in the TX.
ZeXx86
Site Admin
Posts: 12834
Joined: Mon 29. Apr 2013 16:06:44
Contact:

You can find explanation for all parameters when you hover the cursor over the parameter and also in the manual.

Spirit is not using PID, the algorithm is much more sophisticated. It is better to forget everything that you know from VBar as it can lead to situations where you try to fix something but it will not work in that way.
But Pirouette Consistency is really similar to I gain, Rudder Delay to D gain. I can tell you what to set there according to your setup.
Spirit System developer
Post Reply