Adjusting Sim Pedals/Realism

[blekenbleu]

Since this thread's title does not preclude it,
here is Niels Heusinkveld's tutorial about throttle response:

Extracted from that: Assetto Corsa's throttle vs RPM torque curves:

.. vs something more realistic:

IMO, it should not be too hard, e.g. in SimHub, to add a recalculation
based on throttle position HID axis value and engine RPM telemetry,
that provides corrected throttle signals to games for more credible torque.
Whether such correction can be implemented with sufficiently low latency
(it might yield sensations like turbo lag) remains to be determined.

 

[Deleted member 197115]

Doesn't ACC have different throttle mapping tied to ECU maps.

https://www.slipstreamracing.net/assetto-corsa-competizione-engine-map-guide

https://traxion.gg/the-key-to-engine-mapping-in-assetto-corsa-competizione/

 

[Deleted member 197115]

Related to "realism" question, may be Enzo can help.
Why all pedals using prone to over time degradation elastomers instead of springs.
Is it production cost or some other inherent characteristics of rubber/nylon squishy stack.
Always thought that there is no other way, but this kit piqued my curiosity.

https://www.mrpltd.co.nz/product/simtrecs-spring-upgrade-kit/

Many hours have been spent using VRS to log brake trace to compare the conventional urethane/rubber bumpers to the springs and we are happy to say the springs really smooth-en out the brake trace

Springs give the brake pedal better trail braking ability and more overall consistency
The springs also allow a super stiff pedal but also retaining some movement at the same time which we believe gives you better control
Especially good over long race stints as they don’t heat up like urethane/rubber

Oh, wow, they have one for HE Ultimate and Sprint too.

https://www.mrpltd.co.nz/product/he-ultimate-brake-spring-upgrade-kit/

 

[alfye20]

If im not wrong and based on personal experience, springs needs a load to compress and reaching this max load cannot translate very well when pushing a loadcell sensor.
It is like when you reach the max load of the spring, pedal is moving but no variation on the force read by the LC

 

[RasmusP]

If im not wrong and based on personal experience, springs needs a load to compress and reaching this max load cannot translate very well when pushing a loadcell sensor.
It is like when you reach the max load of the spring, pedal is moving but no variation on the force read by the LC

Ehhh that's not how this works. But I know what you're trying to say how springs vs elastomers feel!

The loadcell doesn't care what's between your foot and itself.
More muscle force = higher output.

But usually, elastomers are extremely non-linear. Quite easy to compress a little bit but then exponentially more resistance.
But also never reaching the end. You can continue to press harder and harder and they will always keep compression, although only a tiny bit.

A spring ist usually linear. So you need some minimum force to get it to move and then 2x the force = 2x compression until you hit the end.

But you can also manufacture non-linear springs with the coils becoming thicker, tighter etc, creating exactly the same Pressure-Compression-Curve like elastomers.

It's quite a bit more expensive and needs a lot of research than just buying 3 different types of rubber disks and filling the last gap with a softer, sponge like material.

 

[alfye20]

A spring ist usually linear. So you need some minimum force to get it to move and then 2x the force = 2x compression until you hit the end.

This!
Problem comes just before reaching the endstop of any spring, forces are linear and loadcell barely reacts

 

[RasmusP]

This!
Problem comes just before reaching the endstop of any spring, forces are linear and loadcell barely reacts

No, no, and no, sorry.
I know what you mean by this and that it can feel like that but it's really not the case!

What you're trying to say is:
Until the linear spring starts compressing at all, the loadcell will already show input, probably almost spike, then it will barely go up until you hit the end of the spring and then shoot up.

But that's because your foot actually pushes with that force-curve.

What you mean is force vs travel.
And while our body easily gets confused between force and travel, the loadcell does not.

That's why brake pedals need to be tuned differently for different people.
You need to set up the travel vs force curve so that your personal body thinks it correlates "like it should".

And yes, springs can confuse our muscles like hell!

 

[RasmusP]

To emphasise on this:
They really don't look like your average spring-pedal!
They are tuned to replicate the force curves of real brake pedals and I believe them.

 

[Enzo Fazzi]

Related to "realism" question, may be Enzo can help.
Why all pedals using prone to over time degradation elastomers instead of springs.
Is it production cost or some other inherent characteristics of rubber/nylon squishy stack.
Always thought that there is no other way, but this kit piqued my curiosity.

https://www.mrpltd.co.nz/product/simtrecs-spring-upgrade-kit/

Oh, wow, they have one for HE Ultimate and Sprint too.

https://www.mrpltd.co.nz/product/he-ultimate-brake-spring-upgrade-kit/

Can't speak for other companies of course, but for is it is as follows:
We've developed our new elastomers to have a progressive curve that follows data we've received from different race teams and manufacturers.
You replicate this with linear springs (by using a cam, similar to the clutch pedal), but you then no longer have a linear output from the loadcell (as the cam will change the leverage).

Progressive springs are an option as mentioned, but elastomers in our case are the most cost effective way to give a wide range of different options.

As for elastomers changing over time; we've tested ours at over 3 million cycles (This how much you'd need to brake for more than 5500 F1 GPs) and we did not observe any measurable changes.

This!
Problem comes just before reaching the endstop of any spring, forces are linear and loadcell barely reacts

As far as I know, this is only the case for Asetek Forte and La Prima pedals, as their brake pedals are travel based, not force based.

A brake pedal like ours will always give the same sensor output for a given force applied at the pedal face, regardless of travel.

 

[Deleted member 197115]

This!
Problem comes just before reaching the endstop of any spring, forces are linear and loadcell barely reacts

Load cell reacts to pressure, not movement. Plus with the stack of different springs you can achieve same non linearity as with the stack of different hardness rubber.

 

[Deleted member 197115]

Progressive springs are an option as mentioned, but elastomers in our case are the most cost effective way to give a wide range of different options.

Thanks Enzo, sounds like in theory springs might work.
Wasn't HE the first company that started using current design with elastomers, sounds like the industry just followed the leader without giving it a second thought.

 

[Enzo Fazzi]

Thanks Enzo, sounds like in theory springs might work.
Wasn't HE the first company that started using current design with elastomers, sounds like the industry just followed the leader without giving it a second thought.

I don't know the exact chronology, but people were putting tennisballs under their brake pedals in the 90s already.

 

[f1Simulation]

While this is true to some extent (G-forces will make up somewhere between 5 and 20% of braking force), it is no where near as much as people think it is. You're strapped in tight and you and the car are decelerating at the same rate. F1 drivers we worked with say that using 120KG with our Ultimate pedals is a good exercise for what it feels like in the real thing.


Current F1 cars have a brake-by-wire component, but it isn't a fully digital/electrical system. The pedal is still hydraulically connected to all four brakes, with seperate master cylinders for the front and rear. The front brakes are solely a traditional hydraulic system. The rear wheels get slowed down by 3 components; The brakes, engine braking from the ICE and regenerative braking from the electric motor.
To keep the car balanced, these 3 need to be dynamically regulated (also ICE and regenerative braking changes throughout the race/lap anyway, depending on what the driver needs/wants).

A pressure sensor in the brake pedal will relay to a computer how much the driver wants to slow down. The computer calculates how much brake pressure needs to go to the rear brakes and a valve at the rear master cylinder (similar to ABS systems) will open and close accordingly.

Brake pedal feel (travel) gets changed to what the driver prefers by swapping out parts of the hydraulic system. This is not the same throughout a season, as drivers typically prefer a different feel for Monaco than for say, Suzuka.

F1 and LMP at 120kg on Ultimate with elastomer full stack or shorter possible ?

 

[stigs2cousin]

https://heusinkveld.com/wp-content/uploads/A4_Handleiding_Sim_Pedals_UltimatesPlus__08MAR2022-D.pdf

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