resolved Altitude Hold Oscillation

[Picure]

Hi, is this normal or is it a bug? Altitude hold does not hold the aircraft in a stable altitude during a hover and oscillates over time resulting in a crash. This happened to me on Rotorheads first, then I went on SP free flight to try it again and it was still the same.

Please check the video 

 

[Yuto]

have had this happen to me more than once, had it perfectly set at 100 feet and it kept going up and down after several minutes until i hit the ground and crashed, it seems like the alt hold mode is having problems with the new OB patch, hopefully a hotfix releases soon. 

[placsea]

They tightened the collective SCAS with the latest patch and as a result the saturation tone does not go off near as much but now ALT hold doesn't work properly. Attitude hold has similar issues where it will progressively decelerate or accelerate to the saturation point making it only useful at a hover.  

[Swift.]

If you dig though the FM config lua, you can get an idea of how many variables there are controlling the various axis of the SCAS and the holds. Notably for the collective axis, there are a lot fewer variables than the other axis, and even those with more variables still don't have enough for this type of control system.

I mean, think about all the different values that could dictate behaviour in just the collective alone:

-How much motion you need to input for the SCAS to 'help'
-How fast the SCAS will move from damping to helping
-How far the SCAS will go when helping
-At what point it will return to damping from helping
-How quickly it returns from helping to damping
-How quickly the SCAS responds to transients whilst damping rate
-How quickly the SCAS moves whilst responding to rate damping
-How quickly the SCAS sleeves accelerate whilst responding to rate damping
-How far the SCAS can move whilst damping rate
-How quickly the SCAS responds to transients whilst damping position
-How quickly the SCAS moves whilst responding to position damping
-How quickly the SCAS sleeves accelerate whilst responding to position damping
-How far the SCAS can mover whilst damping position
-How quickly the sleeves decelerate as they near the limit of their authority (to avoid slamming into the stops at great clip!)
 

There are more variables, but tbh I got bored typing.

Hopefully the point is clear, there are a lot of variables that control even this single axis (and that's assuming its symmetric). It's not surprising that we end up with coincidental oscillations when one part of this system it tuned, because with only 3 variables everything is linked!

Edited September 25, 2022 by Swift.

[Raptor9]

Keep in mind that Swift's claims about the control system are assumptions, nothing more, despite stating them as if they were facts. Not everything in the code is open to users to view or edit.

[JIGGAwest]

There is clearly a problem with the ALT hold at the moment. Last patch it worked, this patch, not so well.

[Fakum]

Yup,,, same issue here. I resorted to holding altitude now with the collective myself for now, just a pain till resolved

[gzj3401]

same issue

[BIGNEWY]

Hi all

please be patient as we have some more tweaks to come. 

thank you

[Hippo]

Sorry if it's me doing something wrong, but I think that the ALT HOLD has become much more unrealiable recently.  Several times recently I've experienced what happens in the attached track (an increasing overcorrection which ends in me dropping to the ground), previously this was not happening.

alt_hold.trk

[Dallas88B]

1 hour ago, Hippo said:

ALT HOLD has become much more unrealiable recently

 

[BIGNEWY]

posts merged

thanks