Hydraulic Pedals Brake Fade Idea

[Punknoodle]

So, if you were using a high end pedal set with a hydraulic master cylinder operating a pressure sensor for brake force, you could have a bleed off solenoid in place, possibly controled using PWM and an analog input, which bleeds fluid back to the reservoir. This would have the effect of reducing the amount of pressure on the sensor and thus the braking force, and also it would soften the brake pedal, making it sink, depending on the degree of the bleed. You could get the software to increase the bleed depending on level of brake fade or complete brake failures.

You could even simulate the effect of pad knock off, where the kerbs etc cause the brake pads to be back further from the rotor. In real life this means you have a long pedal until you pump the brakes, which brings the pads up to the disc, which can surprise you in a corner if you haven't brought the brake pedal back up. This could be simulated by having the bleed valve opened and then shutting it once the brakes have been pumped, bringing back the pedal resistance and also braking force.

Just something I thought of randomly.

 

[3ller]

i think the most difficult and the most that have effect on pedal travel initially is powerbrakes/servobrakes on a stationary rig you cant simulate that only fake it with the initial spring lead in method

 

[VBR]

@Punknoodle - Awesome idea! You could have something similar with clutch wear, having to press it down less far as it wears, could be done via software by a game dev.

I'd also like a FFB gear shifter that had some kind of genius mechanism inside that stopped you from being able to shift unless the clutch was activated correctly, & that fed accurate FFB gear crunching waveforms through the stick! Maybe the shifter could have a speaker inside as well that fed audio crunching sounds to go along with the FFB waveforms.

I'd also like a FFB brake pedal that fed accurate ABS waveforms through the pedal. I know Fanatec have their vibrating ones, but the feeling isn't 1:1 with reality.

This is the future!

 

[RC45]

Only for poorly maintained road cars and possibly extreme distance endurance races - at which time you put to have the impending failures worked on.

Track day use normally includes new pads, fluid and up to date clutch maintenance.

I cannot imagine daring to track my car with worn pads and poorly maintained brake fluid levels.

And if the brakes would have issues such as extreme fade or clutch began to show signs of extreme wear or fluid issues its time to pit and call it a day.

 

[VBR]

And if the brakes would have issues such as extreme fade or clutch began to show signs of extreme wear or fluid issues its time to pit and call it a day.

Maybe if you were on a track day, but not if you were battling for a good position in a race.

 

[Punknoodle]

Only for poorly maintained road cars and possibly extreme distance endurance races - at which time you put to have the impending failures worked on.

Track day use normally includes new pads, fluid and up to date clutch maintenance.

I cannot imagine daring to track my car with worn pads and poorly maintained brake fluid levels.

And if the brakes would have issues such as extreme fade or clutch began to show signs of extreme wear or fluid issues its time to pit and call it a day.

Brake fade is a factor in touring car racing, during long endurance races where pad changes mid race are necessary. On that note, if a driver doesn't pump up his pedal after a change to bring the pads back to the disc your pedal goes to the floor. Pad knock off is an very real thing, especially in touring car racing where riding over the kerbs is key to a fast laptime. As the car goes over the kerb it can move the pads away from the disc surface, meaning at the next corner you have a long brake pedal until it's pumped up. This encourages a safety tap of the brakes before coming in to a heavy braking zone to ensure the pads are in the correct position and you have pedal pressure.

Sure it's on the side of uber realism but it's just an idea I had that I could see as a way to simulate this on a simulator.

 

[Punknoodle]

Aftermath of a pad change without pumping the pedal: (This one is good because you also see a car go through the pit process where they change pads and pump pedal)


I couldn't find a good video where someone is clearly explaining pad knock off but if you look at the on board, take a look at the safety tap happening before a big brake application.

 

[RC45]

But either way, this should just be under "simulated failures" - the lap to lap pad knock off pedal taps would vary from car to car and brake system to brake system and would be difficult to simulate in any sort of variation on the pedal system, so you would just end up with a generic "brake needs initial tap to work ever time" feature - and for the pad change situation this should fall under pit change strategy/failures which are based on the racing sim pit modeling implementation.

Its an interesting idea, but would probably best be suited for a single make/model style simulator rig rather than a generic driving sim rig. IMO of course.

 

[JohnBodin]

Interesting idea, but I can't really understand why you'd want your pedals to simulate something that would have absolutely nothing to do with what was going on with the actual physics inside the game/sim itself.

 

[Swagger897]

@Punknoodle - Awesome idea! You could have something similar with clutch wear, having to press it down less far as it wears, could be done via software by a game dev.

I'd also like a FFB gear shifter that had some kind of genius mechanism inside that stopped you from being able to shift unless the clutch was activated correctly, & that fed accurate FFB gear crunching waveforms through the stick! Maybe the shifter could have a speaker inside as well that fed audio crunching sounds to go along with the FFB waveforms.

I'd also like a FFB brake pedal that fed accurate ABS waveforms through the pedal. I know Fanatec have their vibrating ones, but the feeling isn't 1:1 with reality.

This is the future!

As far as automatic cars go, when switching out of park to any drive there's an interlock that requires the brakes to have a current go through them to allow the shifter to even move. This would be super easy as it already exists.

However, it wouldn't stop a forceful shift. It would just cause it to not shift at all.

 

[MozzMann]

NOT all Cars have any interlock , In the US and Europe but at least not all new cars in Oz.
But thats beside the point I am mucking about with some ideas for extracting data from various sims that works by extracting the Brake temp and as a result reduces the brake input voltage thus decreasing the effective braking , as the brakes cool you get better brakes cook them and you get stuff all.
The BIG issue is not all sim's export their Motec type data in the same way,

I am also experimenting with Hydraulic to Electric signal input BUT with tunable ABS and tactile feedback but alas this will be a way off as I have other pressing issues at present.

 

[Rallywagon]

This is actually a good idea. It could be set up in such a way that you could actually simulate proper pedal travel, yet still base your push of muscle memory. You can better simulate brake fade from over heating and fluid boiling and mixed with an accumulator and pump could be used to simulate an abs system. Creating an algorithm to simulate when and how knock off would happen would really not be beyond a group of people who can code suspension geometry.
As for the failure components, several games model brake failures of some sort. It would be nice to have that translates to the brake as well.

 

[Swagger897]

News page:
https://www.gtplanet.net/tokyo-motor-show-brings-updated-gt6-motion-simulator-rig/#comments

 

[Rallywagon]

Ohhh, now that is a neat concept. Find a sliding caliper and mount and place it on a plate that has a load sensor on it to push against.
Bet they used Nissan stuff.

 

[Punknoodle]

Interesting idea, but I can't really understand why you'd want your pedals to simulate something that would have absolutely nothing to do with what was going on with the actual physics inside the game/sim itself.

The idea would be that the software/simulator is directly controlling the brake knock off and is part of the physics.

News page:
https://www.gtplanet.net/tokyo-motor-show-brings-updated-gt6-motion-simulator-rig/#comments

Yeah there have been a few hydraulic based brake systems made but none with a bleed valve that allows for pedal feeling loss.

 

[sesselpupser]

I'd also like a FFB gear shifter that had some kind of genius mechanism inside that stopped you from being able to shift unless the clutch was activated correctly, & that fed accurate FFB gear crunching waveforms through the stick! Maybe the shifter could have a speaker inside as well that fed audio crunching sounds to go along with the FFB waveforms.

I had an idea like this that used solenoids to lock the shifter until the clutch was depressed a certain amount, but in the end I kind of thought it was too digital; in a real car you can shift without using the clutch at all and the rest of it is dependent on the engine speed and the ratios you're switching between, so I didn't think it was worth exploring. I thought of also using electromagnets that could finely control the resistance too but that seemed like a lot of hassle since you'd need quite a high current to give you convincingly high resistance.

As for the pedal thing, it's one of those chicken and egg scenarios that probably won't ever happen, by which I mean there is no mainstream sim hardware that can simulate this so developers don't include the telemetry and brake fade simulation that the hardware would require, so hardware manufacturers aren't implementing it in their mainstream products. It's the same problem as proper mainstream motorbike simulators, they don't exist because no one mass produces the hardware so no one develops motorbike simulators.

That doesn't mean it's not a good idea, though, and I've learned something new today (which is why racing drivers tap their brakes so much), but I suspect the work and money involved means it'll never come to fruition, sadly.

 

[VBR]

I had an idea like this that used solenoids to lock the shifter until the clutch was depressed a certain amount, but in the end I kind of thought it was too digital; in a real car you can shift without using the clutch at all and the rest of it is dependent on the engine speed and the ratios you're switching between....

The shifter also could unlock & let you change gear if your revmatching was in the sweet spot for a downshift. It would be a very complicated thing to build though!