DIY Brake Pedal simulator
From wikiluntti
Introduction
Fluid brakes with vacuum brake booster behavior.
In reality, most of the additional pedal travel comes from:
- Slight expansion of rubber brake hoses.
- Elastic deformation of calipers, pads, rotors, and other components.
- Small clearances being taken up within the system.
- The action of the brake booster.
A master cylinder only system (no booster) behaves more directly:
- Pedal force is proportional to hydraulic pressure.
- The pedal becomes firm quickly.
- To achieve high braking force, the driver must push quite hard.
- This is similar to older cars, race cars without power assist, or a vehicle with the booster disabled.
A vacuum-boosted system has a different feel:
- Light pedal effort produces substantial braking.
- The pedal often travels a bit farther for a given braking force.
- The force-vs-travel relationship is nonlinear because the booster adds force.
- Drivers perceive it as softer and easier to modulate in normal driving.
The "feel" of a brake pedal comes more from:
- Compliance (how much travel occurs per unit pressure),
- Booster assist curve,
- Initial pad contact point,
A common engineering model is:
- Pedal → spring (system compliance) → hydraulic pressure OR Pedal → light spring → stiff elastomer/spring → force sensor
- Spring: hose expansion, caliper flex, seal deformation, pad compression, structural flex, tiny fluid compression
- a two-stage spring: A softer initial rate (taking up clearances and pad contact; spring) and a stiffer rate after the pads are "on the rotor (rubber bushings)."
- Optional booster force added in parallel.
For a road-car feel, you generally want:
- noticeable initial travel,
- progressively increasing resistance,
- moderate peak force (perhaps 150–300 N at the pedal).
For a race-car-without-booster feel, you'd use:
- less travel,
- much higher force,
- a very firm end stop.
Plan 1
Parts
- Piduri peasilinder: MERCEDES-BENZ E-CLASS (W211) (2002-2009), 2004
- Piduripedaal: MERCEDES-BENZ ML-CLASS (W164) (2005-2011), 2006
Gas pedal
- Andur, gaasipedaal: MERCEDES-BENZ ML-CLASS (W164) (2005-2011), 2007
Driving wheel:
- AUDI A6 Avant (4F5, C6) (03.05-08.11), O: 19938, Rool MÜT11
