Slew Rate Questions

Simucube 2
1

I have some questions about direct drive slew rates and am hoping you folks may have some answers.

I’m considering getting either the Simucube 2 Sport or Pro. The only advantage of the Pro for me seems to be that it has a higher slew rate. I don’t need 25NM of force feedback. I’m wondering how high a slew rate you actually need for sim racing and how the 4.8NM/ms compared to something like the small Mige.

My hunch is that 4.8NM/ms is sufficient but I’m not really sure what slew rate is. Would it mean that it takes 3.5ms to reach full force feedback (17/4.8)? And in my normal scenario where I use 40% force feedback I would be hitting the limit in ~2ms?

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2

More torque is not just more power, it’s also more reactivity.
It seems logical because more power = more quicker you can go to a position.

3

My opinion is that 4.8 is way more than enough. Most of the times I run slew rate at 0.5-3.0 or so. I think high slew rates feel more unrealistic and further exposes the active & position/velocity-based nature of game FFB (real-life “FFB” is the opposite being a passive/reactive & torque-based system).

I feel the higher slew-rates further increase the noticeability of the wheel (well motor) being told to do the work and move (again, due to the “active” nature of FFB systems)…at least for the initial changes of velocity/position. The lower slew rates give the first moments of velocity/position change a slightly more realistic feel and also allows you to run less damping overall.

I still need to do lots more tests & comparisons with different slew-rate, damper, friction, and overall power level combinations but, so far, I’ve found the ability to adjust/lower S-R a very welcome feature.

Of course, like with all settings/filters, there are compromises so I’m not advising to go crazy and set S-R to 0.05 :slight_smile:

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4

I thought it would be the opposite if I understand it correctly?

Slew rate off allows the servo to accelerate as fast as it is able to, at which point we might want to add some extra damping.

If we then begin to limit the slew rate, we make the servo less active and can then lower the damping.

That’s how I understood it but feel free to correct me if I have this wrong.

5

Yup, you got that correct.

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6

if that is how it works I guess it would be really useful in r3e, in which the wheel feels always too “gummy” and “springy”, that’s the best way I can describe it :slight_smile: I tried adding more damping both in td and ingame but I think I might try with slew rate

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7

It may help; S-R helps with the initial movement, the change in velocity/position. If R3E has a S.A.T. filter/slider (I don’t think it does but check), try lowering that. Also try lowering the “steering force” or “steering rack force.”

I may have misunderstood what you’re looking for so the lowering of the steering rack force may bring you in the wrong direction :slight_smile: but give it a shot.

P.S. You may not feel much difference setting S-R down a little. I would bring it down a lot to start just to more easily feel the difference. Bring it all the way down to 0.2 or 0.3 to start.

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