• Welcome to PiBoSo Official Forum. Please login or sign up.
 

Controller beginnings

Started by teeds, October 23, 2014, 10:53:08 AM

Previous topic - Next topic

doubledragoncc

Hi "H" can you give the link for the lever set please. Thats a dang good price. My problem is I cant use used parts and need to ensure all parts are good quality and supply is good too. The hydraulic way is better than using cables but more expensive so it will be offered as an option.

This thread is getting good.

DD
GPBOC Live Streams: https://www.youtube.com/c/IASystemsComputerControls; i7 12700K 5.1GHz Z690 ASUS Strix Z690-A Mobo 32GB 3600MHz DDR4 RAM ASUS Strix RTX3080 OC 10GB DDR6X ASUS Ryujin 360 AOI Cooler ROG Thor 1200w PSU in ROG Helios Tower Case.

h106frp

January 12, 2015, 05:29:37 PM #46 Last Edit: January 12, 2015, 05:43:22 PM by h106frp
These ones;
http://www.ebay.co.uk/itm/Pair-7-8-Motorcycle-BIKE-Brake-Lever-Clutch-Master-Cylinder-Reservoir-Hydraulic-/400763208879?pt=UK_Motorcycle_Parts_13&hash=item5d4f5944af

Hoses are the thing that seem to be difficult to find cheap, just have to keep checking and see if any bargains come up. Have discovered than land rover 300tdi clutch slaves are metric and that bearmach cast iron are the ones to go for around £10 ea.

Managed to get a friend to agree to machine my 'special' steering spindle for me so might start to make a bit of progress with the assembly soon :) Want to get basic steer with handlebar controls all working first though before starting on the clever bits like torque steer and feedback.

doubledragoncc

January 13, 2015, 01:49:14 PM #47 Last Edit: January 13, 2015, 01:51:29 PM by doubledragoncc
Thanks H. I found them before but forgot it lmao. Im old.

I am thinking to try with no caliper and just a pressure sensor to save on components needed and weight for shipping. I have to think of these things bugger lol. I think trying different fluids might bring surprise results as you dont need to think about heat. It depends on the brake systems seals. DOT 5 is best as it will not damage paint etc if spilled in the home.

I want to make a system that uses as little amount of components as possible so am trying all sorts of weird and wonderful shit out lol.

It reminds me of when I was a kid watching Blue Peter and how they made so much out of washing up bottles and a sponge lol. God Im old!!!!

DD
GPBOC Live Streams: https://www.youtube.com/c/IASystemsComputerControls; i7 12700K 5.1GHz Z690 ASUS Strix Z690-A Mobo 32GB 3600MHz DDR4 RAM ASUS Strix RTX3080 OC 10GB DDR6X ASUS Ryujin 360 AOI Cooler ROG Thor 1200w PSU in ROG Helios Tower Case.

h106frp

I think without a load piston and the controlled deflection it allows it will be difficult to reliably avoid the system being 'locked' with no lever movement at all as all fluids are incompressible. You could possible add a very small accumulator device to allow some controlled lever movement. This is a link to a commercial device that  might give some inspiration for a home made contraption. You are just trying to compress a fixed small amount of gas a bit like a controlled situation of needing the system bleeding, a bit spongy before the pressure builds up.
http://www.hawe.de/en/products/product/product/ac-mini-accumulators/

The other problem is loosing the option to use a load cell, the only cheap pressure transducers i have seen (<£20 for up to 100 bar) are direct from china, the low pressure car ones (0 to 30 psi) will not be much use and they are still £30+. Slave cylinder+load cell is around the same price of £20 so its only the cost of the brake line that a deal breaker.
I do have a pressure transducers available to me (20, 60 or 100 bar) but i think i will try the load cell first as its easier for everyone to obtain.

Otherwise if might be easier to 'fake it' and modify a proper hydraulic lever set to work with a cable lever / spring / budget 'bath scale' load cell setup. You would have the looks of real bike parts and the simplicity of mechanical components.

Full hydraulic is arguably overkill compared with cable and load sensor - but enjoying the challenge of building a one one off special for myself :)

doubledragoncc

Yeah gotta agree with you. I just know there must be a way to get the right feeling with the right data output some way or another, but thats what this is about, making something that dont exist is so much fun and challenging that when you find the solution it feels 10 times better than getting it off the shelf at a high price. I will stick to washing up bottles and duck tape method lol.

DD
GPBOC Live Streams: https://www.youtube.com/c/IASystemsComputerControls; i7 12700K 5.1GHz Z690 ASUS Strix Z690-A Mobo 32GB 3600MHz DDR4 RAM ASUS Strix RTX3080 OC 10GB DDR6X ASUS Ryujin 360 AOI Cooler ROG Thor 1200w PSU in ROG Helios Tower Case.

HornetMaX

Quote from: h106frp on January 13, 2015, 03:21:20 PM
I think without a load piston and the controlled deflection it allows it will be difficult to reliably avoid the system being 'locked' with no lever movement at all as all fluids are incompressible.
But that's what happens on a real (race) brake system: once the brake pads touch the disk, the brake lever moves no more.
The only movements that are left are due to fluid compression (tiny at usual temps, but gets important if the fluid "boils") and mechanical deformations (lever, pipes, joints, calipers).

The lever should have itself an initial "free" displacement, after that it will lock:


Maybe it's enough, meaning you just need to "put a cork after the lever" and fill the circuit with fluid (i.e no need for calipers, pads and discs).
You'd still need to find a place for the pressure sensor, of course.

I'd tend to agree that a proper lever with a cable acting on a load cell could be enough. I even think that just a cable a spring (sufficiently stiff one) would make such a big difference that going beyond that may be unnecessary ...

MaX.

teeds

If you're not expecting any movement from a fluid based system once it's engaged then it seems bit overly complicated using hydraulics? I was thinking for simplicity and compactness couldn't you rig up a mechanical equivalent using a load cell and some rubber actually within the fluid reservoir? I was thinking you could drill and insert a pivot in the ally reservoir and have a lever going from the push rod to a load cell/rubber/spring assembly on the other end. Would need to be the same as pictured below and not the remote reservoir type but should be as easy as rigging up a complete system if not easier, neat and compact too and no fluids. Hmm...  :)



http://www.ebay.co.uk/itm/7-8-Handlebar-Motorcycle-Universal-Hydraulic-Brake-Master-Cylinder-Lever-Chrome-/181617195237?pt=UK_Motorcycle_Parts_13&hash=item2a493a78e5

HornetMaX

Quote from: teeds on January 13, 2015, 05:38:53 PM
I was thinking for simplicity and compactness couldn't you rig up a mechanical equivalent using a load cell and some rubber actually within the fluid reservoir? I was thinking you could drill and insert a pivot in the ally reservoir and have a lever going from the push rod to a load cell/rubber/spring assembly on the other end. Would need to be the same as pictured below and not the remote reservoir type but should be as easy as rigging up a complete system if not easier, neat and compact too and no fluids. Hmm...  :)
You could probably just stick a load cell where a classical (non radial) lever pushes the cylinder, no ?

MaX.

doubledragoncc

All you need is to have a pressure sensor that could bolt into the master cylinder directly, BUT there would be no space for fluid to move and it would be like the brake is on all the time, the lever would be nearly solid. You would need something for the fluid to press against until it stopped. Dont forget the brake pads only move 2mm to 5mm then hit the disk.......solid lever. Love the lil ol diagram Max. All we need is to have a small unit that bolts between the master cylinder and the sensor, that will move a small amount= initial braking and then block= actual full braking and putting full pressure on the sensor.  This would mean few components and real feel, it will take a bit of playing around to get right but it should work.

Teeds that switch on the master cylinder(universal Harley I custom built them 25 years) its just the brake switch and no use. its digital not analog.

DD
GPBOC Live Streams: https://www.youtube.com/c/IASystemsComputerControls; i7 12700K 5.1GHz Z690 ASUS Strix Z690-A Mobo 32GB 3600MHz DDR4 RAM ASUS Strix RTX3080 OC 10GB DDR6X ASUS Ryujin 360 AOI Cooler ROG Thor 1200w PSU in ROG Helios Tower Case.

h106frp

Cheapest analogue pressure transducers i have found are these from china


http://www.ebay.co.uk/itm/100psi-Pressure-Transducer-or-Sender-for-Oil-Fuel-Diesel-Gas-Air-Water-Pressure-/170980134449?pt=UK_CarsParts_Vehicles_CarParts_SM&hash=item27cf35ce31

Offered in a range of maximum pressures to suit as we do not want the output to clip, could be connected directly to master cylinder output if used as suggested below....

It has an integrated amplifier and the output is ideal for interfacing directly to USB (0-5 volts) so that bits easy.

If you could put a stop block the right length to get your desired lever stroke in the end of the master cylinder without blocking the outlet port or damaging the seals, this combined with a correctly selected rate (stronger) master cylinder return spring might complete the simulated circuit without the need for remote cylinders :).

HornetMaX

Quote from: h106frp on January 13, 2015, 08:30:43 PM
If you could put a stop block the right length to get your desired lever stroke in the end of the master cylinder without blocking the outlet port or damaging the seals, this combined with a correctly selected rate (stronger) master cylinder return spring might complete the simulated circuit without the need for remote cylinders :).
Not sure I understand.

If you bolt that sensor right on the master cylinder, the stroke will be very short: as soon as the outlet port is blocked, the whole thing locks.
Also, why would you need a stronger spring ?

MaX.

h106frp

January 13, 2015, 08:48:04 PM #56 Last Edit: January 13, 2015, 08:54:13 PM by h106frp
Thinking that while the piston crosses the fluid inlet port the only lever pressure is the spring, if you were to use as is or 'open up' the port to suit, the width of the port would give you you the no pressure travel range before it hit the stop block and loaded the lever. Needs a brave soul with a scrap cylinder/drill/steady hand :D to experiment

As i understand, the initial travel of a normal lever is 3 stage, crossing the inlet port gives master cylinder spring load only, then the resistance of the slave piston travel in the caliper (fraction of mm) then the pressure load as the pad force is increased.

....Actually you might not need the stop at all as hydraulic pressure after the port closes is enough, just uprate the spring to feel more like the second step of caliper piston movement

HornetMaX

Quote from: h106frp on January 13, 2015, 08:48:04 PM
Thinking that while the piston crosses the fluid inlet port the only lever pressure is the spring, if you were to use as is or 'open up' the port to suit, the width of the port would give you you the no pressure travel range before it hit the stop block and loaded the lever. Needs a brave soul with a scrap cylinder/drill/steady hand :D to experiment
I'd think the stock spring may just be enough.

Quote from: h106frp on January 13, 2015, 08:48:04 PM
As i understand, the initial travel of a normal lever is 3 stage, crossing the inlet port gives master cylinder spring load only, then the resistance of the slave piston travel in the caliper (fraction of mm) then the pressure load as the pad force is increased.
Yep, right. But absence of phase 2 shouldn't be a big deal (unless the stroke is really too short).

MaX.

h106frp

Typical, just shows how these discussions contribute to a bit of lateral thinking... just ordered my slave cylinders for the car sim approach  ::)

Quick 'in my head calc' for the lever unit i bought suggests that the pressure for 20kg force at the lever (totally guessing for very heavy braking) and 5:1 lever ratio would be around 300psi out from the master cylinder, so the 500psi sensor unit might be a reasonable start point.

Need some ideas of how 'wide' the typical master cylinder inlet port is and possible methods for making it longer in front of the piston, drill/file/dremel etc.

Could be quite a graceful approach to the problem though.

teeds

Quote from: HornetMaX on January 13, 2015, 06:00:40 PM
You could probably just stick a load cell where a classical (non radial) lever pushes the cylinder, no ?

Yea if there's enough room for the initial travel, spring and sensor etc. Also maybe the plunger could be extended to protrude beyond the banjo bolt hole, mounting the sensor where the banjo would normally sit. I need to have a rummage in my garage see if I have a front brake lying around to play with.

Quote from: doubledragoncc on January 13, 2015, 07:59:34 PM
Teeds that switch on the master cylinder(universal Harley I custom built them 25 years) its just the brake switch and no use. its digital not analog.

Umm yea thanks for that DD  ::)  lmao   ;)