Hs3 Hydraulic Brakes and Clutch

[uberslug]

I agree the amount of friction is proportional to the pressure, however, once the system has reached maximum pressure any additional force on the lever is absorbed by the expansion of the brake lines.

Ah OK then, it was a bit unclear when you first stated it.

If braking force were merely dependent upon system pressure we would have massively large brake calipers with massively large pistons and very small master cylinder diameters. In addition, levers would be REALLY long with very high pivot ratios.

But that's mostly the case no ? Multi-piston calipers(more practical than one larger piston), braided hoses, small master cylinders, high leverages ... all stuff we have on sports bikes.
Not the long levers of course, for obvious resons

Modern braking systems rely on the friction created when two materials are rubbed against each other for their braking force, not the overall system pressure.

Oh man, you lost me again That (rubbing) friction depends on the pressure.
If it wasn't dependent on the pressure, we wouldn't need braided hoses (just lower the leverage to get a lower max pressure with just as much braking force).

And just so we are comparing apples to apples: In my argument(s) I am defining 'Braking Force' as the drag the braking system introduces to the rotational velocity of the wheel, not the amount of force being exerted upon the brake pad / disk combination.

And what I'm trying to tell you is that the two are proportional
The more you press the pad against the disc, the more drag you get.

We are saying the same thing, however, I am taking into consideration the physical limit to the amount of pressure that can be exerted on the brake pads. Even though this limit exists, braking technology advances due to the invention of materials with higher coefficients of friction.

[HornetMaX]

@HornetMax :

that's the point, if he uses transductor its to get pressure on the hand as a real brake, so the feeling would be the same.

Yeah but the point of the discussion with uberslug and h106frp was that they seems to think (if I understood them correctly) that a simple setup like dd's (real lever+master cyl + hose + pressure sensor and a cap) will not results in something that feels like the real thing (for reasons like initial displacement or others). Just trying to understand, dd is anyway already testing

We are saying the same thing, however, I am taking into consideration the physical limit to the amount of pressure that can be exerted on the brake pads.

In dd's case: whatever breaks/bulges/leaks first, the master cylinder, the hose or the pressure sensor

[uberslug]

@HornetMax :

that's the point, if he uses transductor its to get pressure on the hand as a real brake, so the feeling would be the same.

And i'm glad to see that we agree with DD, theory and practic are oftenly different, it needs to be tested and retested.

"The Bumblebee can't fly, Aeoronautics theory has proven it. But he doesn't know about aeronautics, that's why he is actually flying..."   

Technically, the feeling would only be the same if there was a range of little resistance [gap between the pads and the disk] followed by a range of increasing resistance [as components compress and expand]. I have not studied the design but from what I see in the picture, and if the system is fully bled of air, it is dead headed which means it starts creating measurable pressure immediately upon lever movement. It will, more than likely, produce better results than a potentiometer but it will not truly duplicate the 'feel' of a real brake lever.

I would guess one could leave a bit of air in the system [to act as a progressive rate spring] which would more closely replicate the initial lever movement. This band aid would cause its own list of problems and would not truly replicate the feel of an actual braking system but it would be close.

I built my glorified game pad using a caliper, a braided steel brake line, a load cell, and a faux brake pad to actuate the load cell. Once properly bled it operated and felt exactly like a real life brake system [since it is]. It also provided the tactile feed back I was looking for. It was, however, expensive [even with used parts], consumed a lot of space, and was / is potentially messy / hazardous.

DD's design is simple and compact which makes it far more marketable than a 'real life system'. My contributions to this thread should in no way be construed as being critical of his system.

[uberslug]

@HornetMax :

that's the point, if he uses transductor its to get pressure on the hand as a real brake, so the feeling would be the same.

Yeah but the point of the discussion with uberslug and h106frp was that they seems to think (if I understood them correctly) that a simple setup like dd's (real lever+master cyl + hose + pressure sensor and a cap) will not results in something that feels like the real thing (for reasons like initial displacement or others). Just trying to understand, dd is anyway already testing

We are saying the same thing, however, I am taking into consideration the physical limit to the amount of pressure that can be exerted on the brake pads.

In dd's case: whatever breaks/bulges/leaks first, the master cylinder, the hose or the pressure sensor

I may be wrong, but, it looks like the transducer is screwed directly into either the end of the master cylinder or a coupling of some sort. I do not see any length of hose between the transducer and the master cylinder. This is why I am writing that the system is truly dead headed as there are no components that provide any expansion.

[speedfr]

Perfect and thanks to both of you, i can understand a lot better now what you guys was saying.

And yes, the feeling won't be the same, but the esssential is to have the end of braking that feel the same, i mean you know when you press hard and harder that you brake harder. Anyway, the feeling comes from practice in the game.

And @Ubersulg, if i well understand what you did, you are actually braking on a regular system except the disk is changed by a loadcell and then you push the pads on the loadcell when you brake, am i right ?

(to be honest, that what i was thinking of doing at first, keeping a real brake from my Husky or coming from a wreck place, and brake as natural using a potentiometer for the measure of distance).

I wrote a mail to BRD to know what they use for this braking measure, they claim to use regular braking stuff in their simulator, we will see their answer.

in case somebody wants to get to them, its in UK (they makes simulator using Kunos Simulazioni software - Assetto Corsa)-->

BallRacing Developments Limited
Unit 12 Lawson Hunt Industrial Park
Broadbridge Heath, Nr Horsham
West Sussex
RH12 3JR
UK
Tel: +44 (0) 870 777 5757
Fax: +44 (0) 870 777 5858
Email: info@brdsim.com



(preparing Round 3 picture....  )


Edit :

@HornetMax :

that's the point, if he uses transductor its to get pressure on the hand as a real brake, so the feeling would be the same.

Yeah but the point of the discussion with uberslug and h106frp was that they seems to think (if I understood them correctly) that a simple setup like dd's (real lever+master cyl + hose + pressure sensor and a cap) will not results in something that feels like the real thing (for reasons like initial displacement or others). Just trying to understand, dd is anyway already testing

We are saying the same thing, however, I am taking into consideration the physical limit to the amount of pressure that can be exerted on the brake pads.

In dd's case: whatever breaks/bulges/leaks first, the master cylinder, the hose or the pressure sensor

I may be wrong, but, it looks like the transducer is screwed directly into either the end of the master cylinder or a coupling of some sort. I do not see any length of hose between the transducer and the master cylinder. This is why I am writing that the system is truly dead headed as there are no components that provide any expansion.

That's exactly what i meant, there's no tube that could "take" some of the pressure gain (even if we don't want it, that's why we use Avionics tube (still don't have the good terms, sorry) so it wouldn't grow during braking and absord parts of the pressure. But here the pressure goes directly to the head of the transductor.

Example of "Durit Aviation" to have a better reliable braking : https://www.bst-moto.com/durite-aviation-rub_fr_237.html

[uberslug]

And @Ubersulg, if i well understand what you did, you are actually braking on a regular system except the disk is changed by a loadcell and then you push the pads on the loadcell when you brake, am i right ?

(preparing Round 3 picture....  )

Yes.

[HornetMaX]

I think there's more to gain with a proper software setup (pressure to GPB input curve) than with anything else.
Even if dd's system is dead headed and is stuck after the initial "no output" movement.

Side note: most car freaks seem to be pretty satisfied with the feeling of load cells without and fluid circuitry.

Personally I'd tend to think that for us, something as simple as a 1st soft spring for initial lever movement + a 2nd very stiff spring for actual action + a proper curve on this should be more than enough.
But as it would need to be custom built, maybe it's easier to go along with what dd is doing, at least he can use real parts.

[speedfr]

Yes, what DD uses is the simpliest.
No movement, just the reading of the pressure, no hose (tube?) no pads, no heavy stuff, simple and direct. Just need to be linked to LEoBodnar controller and ready to go.
Really simple and efficent, and  a real brake feeling. That will be great.

On car sim, the guys are using a lot of loadcell now, but it's a single brake, on a foot. Which is easy to make and link but on the handlebar, on the front brake, it will need cable and complex system to go press or push the load cell. Ubersulg system is great but heavy and complex, and probably not good enough to be sold as a finished product.

I even have seen a guy stealing the gauge of his wife balance to make a load cell braking system. It works great. But not appliable for hand braking.

That changes from the usual pitbabes !!!

[doubledragoncc]

The system is fully bled but this particular master cylinder unit allows a small amount of lever movement before it hit pressure. I find it helpful and as said before it will boil down to getting used to the feel and how it works in GPB before I can really comment on it all. I have to build a complete system as I must change a lot to get the parts to all fit each other from using cable units before.

I cant see a real reason anything should break or leak as long as the parts are quality enough and I just treat it with respect and find its limitations.

Either way it will ave me at least 10 hours of 3D printing so really hope it all pans out.

Thanks for all your input.

DD

[doubledragoncc]

Just done first full system test with front and rear hydrulic brakes.....................frickin love it, so much more feel for front brake. Rear brake needs to be bleed more but is hard due to design as it has no blled nipple..................no nipples no fun lol.

Will figure it out but will make a video tomorrow to show it in GPBikes and Ride2 and maybe The Crew.

DD

[KG_03]

DD, maybe you remember that during your last live stream I have said that controling a virtual bike with countersteer axis would be more realistic. Now I have to admit that I was wrong. Despite irl we control the bike lean with countersteer, in virtual world having a feel of a lean is more important than minimal conter movement of handlebar. I really love your idea and the way the handlebar is made - fantastic work. 

[doubledragoncc]

Actually KG, irl you apply pressure with your right arm on the bars to countersteer, ie as if turning the bars to go left, on the Hs3 system if you are leaning right you are therefore pushing with your right arm which in real life give pressure on the bars, and this means it IS counter steering and feel natural.

Back to the hydraulic brakes.......................soooooooooo in last nights stream all was good until I tried The Crew and the front brake was so weak I was not sure why and gave a bit too much effort and blew the 500psi transducer!!! A normal person applys about 300psi of pressure when squeezing their hand in a fist so 500 should have been okay, BUT, naturally there is the mastercylinder to concider and I have now taken the 1000psi off the rear brake to test for the front brake.

I was really giving the lever force, far more than you ever would in real life but this is why I test everything for the possability of missuse and apes using the system.

So far I am really happy with the feel of the brake and am now 99% sure it will be stock on future systems.

The dogleg levers feel great too and am keeping the clutch with cable and potentiometer for now.

I hope to do a better live stream later today. Yesterday was totally lacking in setup before I streamed as it is a war zone in my room lol

Rear brake is proving harder to bleed this time and wonder if it is the 90 degree adapter causing problems but will get it sorted today with luck. Only problem is I only have a 300psi transducer in stock and have to wait on the next 1000psi one. Its a slow process to get right but I will prevail lol.

DD

[Hawk]

Your doing a great job there DD... Keep up the great work mate!

Remember that with a lever the potential PSI pressure will be so much greater than the 300psi when just squeezing your hand, but the 1000 psi replacement transducer should be enough I would've thought?

[speedfr]

Hi !

Searching for what value to use, on karting pro or for racing data reporting, they use 100 bar transudcer so that makes 1450 psi. I guess they take a little extra in case but that seems to be the "average" when i went to look for that kind of stuff. Adding the fact that when real brakes works, they get hot and so the pressure as artificial raise but still, 100 bar seems sturdy enough.

speedfr

[doubledragoncc]

Not forgotten you speedfr just been very busy.

What does that transducer cost though?

DD