Steer assist causing violent shaking/oscillation

REVERSEDSKIES · Jun 1, 2024

Hiya

I know this kind of thing showed up from time to time but nothing seems to fix it for me.
I don't have a video and I currently can't connect my wheel to show it, but I have an issue in Assetto Corsa seemingly only with cars which have the setting "steer assist".
I have a Fanatec CSL DD with boost kit and the P1 V2 wheel. One of my favourite cars is the formula hybrid from RSS, but obviously I don't want to drive it with power steering, I want it to be at least somewhat realistic. However, when I put the steer assist on anything below 70 or something, the wheel violently shakes and oscillates at any speed other than 0. It of course gets worse the lower that setting. Sure at a speed of like 0.5kp/h it only shakes violently but ant faster and the wheel can't be held still. This is only with the wheel in the center. The moment I steer a little bit it stops and it's fine, but that doesn't make driving down a straight particularly fun of competitive (even when trying to race AI of course).
I've already tried messing with the experimental settings in content manager, tried wirh and without the gyro setting, tries FFB filter but nothing seems to work. Also tried the recommended settings for my wheel for Assetto from the Fanatec forum + the auto preset. Tried with their recommended FFB settings in Assetto plus some presets in content manager but it does nothing.
Now because this only happens with cars that have the "steer assist" setting, I heard you might be able to take out that setting in the .ini file for the mod, but I can't find the file for it either. I've tried a few cars so far and any car that doesn't have that setting works fine, nothing to worry about. It's specifically only the cars with that setting.

I can't find anything else that I could try because so far what I found is about the same. A lot of people suggest the gyro option, but that does nothing.
So I really hope someone has any idea because I just wanna play the game normally again. My old T300 RS had no issues wirh Assetto at all and my fanatec only has issues with cars wirh the steer assist setting.

So thanks for any suggestions!

REVERSEDSKIES · Jun 1, 2024

REVERSEDSKIES said:
Hiya

I know this kind of thing showed up from time to time but nothing seems to fix it for me.
I don't have a video and I currently can't connect my wheel to show it, but I have an issue in Assetto Corsa seemingly only with cars which have the setting "steer assist".
I have a Fanatec CSL DD with boost kit and the P1 V2 wheel. One of my favourite cars is the formula hybrid from RSS, but obviously I don't want to drive it with power steering, I want it to be at least somewhat realistic. However, when I put the steer assist on anything below 70 or something, the wheel violently shakes and oscillates at any speed other than 0. It of course gets worse the lower that setting. Sure at a speed of like 0.5kp/h it only shakes violently but ant faster and the wheel can't be held still. This is only with the wheel in the center. The moment I steer a little bit it stops and it's fine, but that doesn't make driving down a straight particularly fun of competitive (even when trying to race AI of course).
I've already tried messing with the experimental settings in content manager, tried wirh and without the gyro setting, tries FFB filter but nothing seems to work. Also tried the recommended settings for my wheel for Assetto from the Fanatec forum + the auto preset. Tried with their recommended FFB settings in Assetto plus some presets in content manager but it does nothing.
Now because this only happens with cars that have the "steer assist" setting, I heard you might be able to take out that setting in the .ini file for the mod, but I can't find the file for it either. I've tried a few cars so far and any car that doesn't have that setting works fine, nothing to worry about. It's specifically only the cars with that setting.

I can't find anything else that I could try because so far what I found is about the same. A lot of people suggest the gyro option, but that does nothing.
So I really hope someone has any idea because I just wanna play the game normally again. My old T300 RS had no issues wirh Assetto at all and my fanatec only has issues with cars wirh the steer assist setting.

So thanks for any suggestions!

I hate auto correct man.
Also can't edit the title for some reason. Thanks overtake.
It's supposed to say "Steer assist causing violent shaking/oscillation"

Stereo · Jun 2, 2024

The neutral value that is used on cars where it's not adjustable is 100%. "Steer assist" is a misleading name, 100% means completely linear input to output, lower values are lower exponents (force^0.7 for example for 70%) which increases midrange values.

The 'range compression' settings in CSP FFB are the equivalent and will give it a function that oscillates much less, name's different because it's not power assist or anything of that nature.

REVERSEDSKIES · Jun 2, 2024

Stereo said:
The neutral value that is used on cars where it's not adjustable is 100%. "Steer assist" is a misleading name, 100% means completely linear input to output, lower values are lower exponents (force^0.7 for example for 70%) which increases midrange values.

The 'range compression' settings in CSP FFB are the equivalent and will give it a function that oscillates much less, name's different because it's not power assist or anything of that nature.

Okay I'll have to try that setting soon then when I can connect my wheel again. But I do have to ask, what setting should I use for range compression? Currently I see it's at 100% And how can I make a car feel a bit more realistic, such as no feeling of power steering in a car that doesn't have it, like the F1 cars from RSS? And would it possibly be better to enable some other settings since it is a direct drive wheel? I've never actually seen these FFB settings in CSP before.
Also, I haven't actually tried putting the steer assist at 100% in the F1 car, but given that 80% (which is the default) already feels insanely light I'm assuming 100% to be even lighter. Again, haven't tried that yet, but IF that is the case, how come the default value of 100 for cars that don't have the setting feels so widely different?
And, if you have an answer to this, how come this setting doesn't cause this kind of thing on something like a T300 RS? Is that a thing to do with deadzones possibly?

I know I'm asking a lot of questions, sorry. I had hardly any issues with the game on my T300RS, only my T300RS had issues back when I had it, that's why I upgraded. Hadn't had any issues on Forza with this wheel but now on Assetto I do. I'd like to understand a bit more of how it works and what settings really do to know what I might wanna change if anything else ever comes up. I did a bit of looking around but you get a little conflicting info on what a setting really does it seems.
Thanks for the reply tho! I'll definitely check it out as soon as I can.

Stereo · Jun 2, 2024

Very ballpark cause it's not really how power steering works, but you'd want range compression at 100% for cars without power steering, and probably 300-400% for cars that do have power steering.

The problem with making it linear is you get light forces at lower speeds to give it headroom to reach the very high forces that are possible in top speed cornering. So making it more realistic usually makes it feel lighter.

Which is why power steering tends to be some variant on - first 1-2N.m of force unassisted, then there's about 50-100N.m that gets reduced by a pretty big ratio (up to maybe 8:1) until you max out the assistance at around 7-10N.m of effort and then it's unassisted again. The actual numbers depend on the designed forces of the car so there's not a one size fits all.

REVERSEDSKIES · Jun 2, 2024

Stereo said:
Very ballpark cause it's not really how power steering works, but you'd want range compression at 100% for cars without power steering, and probably 300-400% for cars that do have power steering.

The problem with making it linear is you get light forces at lower speeds to give it headroom to reach the very high forces that are possible in top speed cornering. So making it more realistic usually makes it feel lighter.

Which is why power steering tends to be some variant on - first 1-2N.m of force unassisted, then there's about 50-100N.m that gets reduced by a pretty big ratio (up to maybe 8:1) until you max out the assistance at around 7-10N.m of effort and then it's unassisted again. The actual numbers depend on the designed forces of the car so there's not a one size fits all.

Okay there's something I don't really understand. Currently the range compression is already at 100%. If I were to turn up the steer assist setting on the F1 hybrid to 100% or even leave it at the default 80 it will be light the entire time. Not just at low speeds but also at high speeds. It just makes the overall steering light regardless of the speed, giving you the feeling of power steering in a way. Sure this doesn't give me the oscillation but there's only a very, very small difference in feel at low and high speeds, but it's hardly anything so it's hardly noticeable, making it feel like you're driving with power steering.
Isn't there a way to just get rid of the oscillation? Other cars that don't have that setting available don't suffer from it but can feel pretty heavy. Heavier than that formula hybrid at any level of steer assist that doesn't oscillate the wheel violently. Surely there has got to be something right? Because if I leave the range compression at 100% for a car without power steering like you said then it's already said right. But that's when the steering feels so incredibly light.

Stereo · Jun 3, 2024

The way steer assist works is the lower the number, the more it increases forces that are not the maximum output.

So, for example, at 50% force output by the game, you'll get 50% from the wheel (100%), 57% (80% assist) or 66% (60% assist). If you want to feel the same strength, you need to adjust the overall strength at the same time. Eg. go from 80% assist + 100% strength to 100% assist 114% strength, and you'd have more similar mid range forces.

The reason it oscillates is the steer assist function's derivative is infinite at 0. The infinity means there's no principle like "at 80% assist, it'll be at most 5 times higher than with no assist" - at 80% assist, small forces are infinitely higher than at 100% assist. The more dead zone the less likely you are to feel this, cause for example at 80% assist, by the time it hits 1% force, it's only multiplying it by 2.5, so if you have a >2.5% deadzone, it'll be pretty normal.

Turning on the csp setting for range compression replacing steer assist gets rid of this infinity so it won't oscillate in as many situations (high enough derivative near 0 will still eventually oscillate even if it's not infinite though). It makes it a simple principle: at 200% range compression, forces will be at most 200% larger than with it disabled. The actual equivalent is I believe the inverse - 80% assist will be replaced with 125% range compression, 50% assist will be 200% range compression, etc.

Power steering systems will create curves like this, which is why I say steer assist is similar to enabling power steering:

At low forces it doesn't assist you, so you feel more force, then as force gets higher it assists you, so you feel less of the additional force. Until you get to the maximum assistance, at which point force rises at the original rate again. The reason this seems "backwards" is that either way it's pegged to the maximum force your FFB wheel can generate, so you only feel the first parts of the shape.

Cars designed for use without power steering will have lower absolute force at the maximum steering effort expected; the target is still the driver not needing to expend more than, say, 10Nm of effort to completely control the car. Power steering just lets them use steering geometry that generates much higher forces but the power hides it from you.