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Steer KDamping value

Started by h106frp, November 26, 2015, 10:59:31 PM

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h106frp

November 26, 2015, 10:59:31 PM Last Edit: November 27, 2015, 01:19:40 AM by h106frp
In the bike.cfg file 'steer' section what are

KDamping0 = 0
KDamping1 = 0.2

I have been tinkering with Yohji's 990 V1 model and altering these values to

KDamping0 = 0.8
KDamping1 = 0.1

has made the bike a joy to ride, the violent head shakes (often started by very small lean angles) are calmed down and cornering is much more stable.

Front braking confidence is massively improved  :)

But i am just guessing at values  ???

Not tried it yet but anyone know exactly what

Damper = 4.7
DamperPower = 1.5 <-- changed this to 2.5 and got cores after a big crash  :(

relate to ?

Thanks

Did some more tests and it seems 'damper' can be raised a bit without problems, currently at

   Damper = 6.7
   DamperPower = 1.5

   KDamping0 = 0.8
   KDamping1 = 0.2

With yohji's 990 V1, still guessing at what the values actually do  ??? but a massive improvement over the stock bike

Its brilliant! Bike holds a good line on turns, headshakes are controllable (and realistic), front and rear slides are saveable, best feel i have had for the 990 with beta 7.

Highly recommended that you give it a try  :)

HornetMaX

Quote from: h106frp on November 26, 2015, 10:59:31 PM
Not tried it yet but anyone know exactly what

Damper = 4.7
DamperPower = 1.5 <-- changed this to 2.5 and got cores after a big crash  :(

relate to ?
That's our beloved steering damper. From this thread :

Quote from: PiBoSo on March 01, 2014, 09:46:58 PM
2. Steer damper. Damping torque = Damper * (steer speed ^ DamperPower)

Incidentally, the thread goes on discussing stuff about the rear suspension, stuff that is currently being improved by PiBoSo.

h106frp

Thanks,
That probably explains why raising 'DamperPower' above 2 causes problems  ;D

Oddly the KDamping values seem to be much more effective, K is usually stiffness so i wonder if its meant to be a value for Q, not sure why we have 2 values though

crappy quote from wiki for people i have just confused    :) "In physics and engineering the quality factor or Q factor is a dimensionless parameter that describes how under-damped an oscillator or resonator is, and characterizes a resonator's bandwidth relative to its center frequency."

HornetMaX

I don't think I've had any reply from PiBoSo on what KYaw, KDamping0 and KDamping1 are. I think he sort of implied they are related to the "yaw controller" (that tries to keep "neutral steering behavior", no over/under-steer), but that's all. I'd say that KYaw is the gain of the "yaw controller" (K prefix is often used for gains in control systems), the two others I have no clear guess.

h106frp

November 27, 2015, 10:40:44 AM #4 Last Edit: November 27, 2015, 11:25:29 AM by h106frp
Tweaking the values so far has produced a nice bike and pleasant to ride especially first person (the shakes are not fun in1P) but still has the character of the stock 990. Even i can do consistent lap times with it and i am not getting the silly falls that i seemed to get with the original bike and b7. It even seems to go where i point it  :)

I have managed to get it named up correctly (first time file dabbling) to use in game and i am hoping Yohji will allow me to post it, not sure my outgoing messaging is working though.

Its a great replacement for the stock bike and has definitely brought the fun back to b7 for me.


HornetMaX

Just post the tweaking you've done (I guess it's all in the bike.cfg) in a "code" section (the #, "insert code"): it would be interesting to see what it does on the stock 990.

h106frp

Im guessing that Yohji pivot mod is a big part of it, i just tweaked from there using the first run down the straight and up eau rouge to gauge the tweaks as this messes up the stock bike completely.

More interested in the feedback from someone else really - i might just be in placebo land  :)

I will PM you and Nick a link if that is alright, i would be interested in your judgements.

HornetMaX

Quote from: h106frp on November 27, 2015, 12:05:44 PM
Im guessing that Yohji pivot mod is a big part of it
No need to guess, that's why it would be nice to test it on the stock 990 :)

h106frp

Tried just setting pivot to 0 on Yohjis model but the suspension rear balance still seems evident.

Maybe try and change a stock 990 later on but busy today  :(

Napalm Nick

H - tried your modded test bike vs the normal bike and agree the tankslappers are less violent but seemed to have more front washouts?

However this test feedback is completely useless as I cannot do more than one lap offline because it always cores.

Doesn't matter what bike or what track it just cores out every time. Have hardly any problems online. Any suggestions for that problem warmly received  ::)
"The post you are writing has been written at least ten times already in the last 15ish years. Its already been reported, suggested, discussed, ignored or archived (but mostly ignored). Why are you doing it again?"

h106frp

Odd, just done 10 laps of Mallory and a couple of spa on the bike with no problems to check. Even tried some big crashes as well but all OK

I remember a few weeks ago you were having trouble before offline, is it ok with the stock bike?

With the pivot at 4 or 5 and rake at 23 degrees i find the front very stable and the usual cause is bringing the back round due to too much power and lean.

With the improved geometry you do not need too muck rake as the bike sits better.

I will have a look at the files and see if i can spot anything. Thanks for taking the time to try it anyway.


Napalm Nick

It is the SAME problem H, not related to your bike, as I said it happens all bikes all tracks.

Have been playing with graphics settings and stuff to try and cure it but gawd knows. But if it works online Im happy with that. Try again after B8 is released lol.
"The post you are writing has been written at least ten times already in the last 15ish years. Its already been reported, suggested, discussed, ignored or archived (but mostly ignored). Why are you doing it again?"

h106frp

Strange, you would think the problems would be with online.

The experiment has now been approved so you could try it in 'local online mode'


HornetMaX

Quote from: HornetMaX on November 27, 2015, 08:55:43 AM
I don't think I've had any reply from PiBoSo on what KYaw, KDamping0 and KDamping1 are. I think he sort of implied they are related to the "yaw controller" (that tries to keep "neutral steering behavior", no over/under-steer), but that's all. I'd say that KYaw is the gain of the "yaw controller" (K prefix is often used for gains in control systems), the two others I have no clear guess.

Rethinking about it, I got a bright moment. If Ye is the "yaw error" (difference between the current yaw and the target yaw), Ye_dot its time derivative, then the output of the yaw controller could be: KYaw * Ye + (KDamping0 + KDamping1 * speed) * Ye_dot




h106frp

Thanks for the info,

Something very odd with 'DamperPower' raising it (tried 1.9 but haven't worked through all the values) leads rapidly to cores, lowering it even below 1 seem to have a positive effect on the bikes cornering with less front washouts  and the shakes do not seem to get worse ??? - now knowing how this value is fed back to steer torque i am starting to wonder.......