Tweaking Gains

[Opto-Mystic]

OK , I admit that I am not fully conversant with terms like yaw etc ...Forgive the newcomer';s terminology 

I am still questing for a slow AND smooth rotation (yaw?).

In D,R EXPO, I have set CH 4  D,R <-- and --> at 50% with EXPO left/right still at zero. This has given me far more rotational control. I will experiment with this later.

A fellow enthusiast (experience/skill unknown) saw my ';First Flight'; and left a comment: "...just fine tuning your gain to get smooth rotation during flight"
DJI F450 Flamewheel First Flight on Vimeo

I would like to do this but I do not want to alter anything until I understand what it does and the implications especially if I have to fly to see the result. So, as I have no idea what ';gain'; actually does I would appreciate advice/explanation on what gain is and what does it do and its effects on the various controls.

Thanks

[Richlizard]

I have asked this question so many times and nobody ever really explained it.

It seems to be something you adjust to get better control, but is a magical thing of mystery. I fear if I ever do find out, I may become a target of alien hitmen!

[Hands0n]

Generally speaking, the gains are nothing more than a control that alters the speed of response of the multi-rotor to a specific input, whether that be from your TX';s control sticks or the auto-whatever mode that the FC (flight controller) is causing.  That may be, in the case of Stablise, the FC sending pitch and roll adjustment signals to the flight controller logic.  Or it may be in response to you making trimming adjustments to any of Yaw, Pitch, Roll.

If the gains are too high the resulting physical movement of the multi-rotor will be twitchy, sudden, exaggerated in relation to the input control.  If the gains are too low the movement will seem delayed, laggy, or unresponsive. 

The key is to get the gains set just right for your requirements - and the aircraft';s.

In terms of the Yaw gain - if you find the multi-rotor responds too much to the stick input then lower the gains a little at a time until you get what you want.  Don';t over-do it or it may not Yaw fast enough for general flying and object avoidance (trees, buildings, stuff).  Just work at the setting until it does what you want and need it to.

In the final analysis, there is absolutely no substitution for trying it out for real.  There is no amount of theory or reading that will substitute - too many variables between each aircraft and specific environment to make publishing a set of PIDs viable other than for a starting point. And in that case you may as well start with the default PIDs that come out of the box. 

Give it a go, gently, small adjustments, test each before adjusting some more. That would be my suggestion.

HTH

[Opto-Mystic]

Thank you Danny. That has made it very clear & most helpful. Now I understand why so many folk have access to their gains via the TX or laptop in the car!

In general terms, I am happy with the current set up and it is the rotation that I want to get slow and smooth for videoing. I am sure that as I get more of the ';feel'; of the sticks, I will get the urge to do tweaking of other controls.

[Hands0n]

Glad to help, Donald. I found that after a little while, with the FPV, it became quite natural to move the Yaw less as I got the "feel" as you say.  Now it is with a gentle and tiny movement the quad Yaws beautifully, gliding its view across the horizon.  I';m by no means perfect at it yet - needs more practical use and practise but I definitely feel that I';m getting there.

Some folk dial in a bit of expo on their TX to lower the amount of control coming from the TX itself. I can';t remember if you can adjust the Yaw expo in your TX, turning the stick movement from a straight line to one that has a flattening in the centre. That way the initial movement is gentle and gradual, then as the stick moves more to its extremes the movement is much stronger, rapid.

[Opto-Mystic]

Yes, I have dialled expo in but at the moment it is a straight line was 100/100 but now 50/50. I have it selectable on SWA so that I can still arm the motors - later I will play with creating a curve to make the yaw less sensitive in the middle  but still hit 100/100 for arming and do without the switch (there are so many switches on the Futaba T8J that I can leave SWA dedicated to that task!)

I am a believer of only altering/tweaking one item at a time, so will not be messing with expo while getting the feel for ';gain'; changes.

Again, thanks