Hi guys,
I'm wondering if someone here is modelling Fx/Camber ... there's
nothing about camber in longitudinal Pacejka... but I think that's
plain wrong and Fx should decrease with camber...
Shouldnt it?
Question 2:
Any good links or SAE papers about brakes/temperature relations?
Thanks...
On 19 Feb 2002 08:30:21 -0800, [email hidden] (Stefano Casillo)
wrote:
>Hi guys,
>
>I'm wondering if someone here is modelling Fx/Camber ... there's
>nothing about camber in longitudinal Pacejka... but I think that's
>plain wrong and Fx should decrease with camber...
Hm, perhaps yes. You'd say with a lot of camber Fx would surely
decrease, since the contact patch gets smaller (less wide).
But perhaps wasn't big enough to add to Pacejka? (hm, lots of tiny
things go into Pacejka, so you would say camber would be at least of
the same importance as many other coefficients).
>Question 2:
>
>Any good links or SAE papers about brakes/temperature relations?
I have no idea. However, I'd say it's a matter mostly of raising
temperature and lowering it based on braking power, where the relation
is quadratic (since we're dealing with an area, not really a volume
and certainly not a line).
So what I want to do in the future is:
- float tempRiseCoeff, tempFallCoeff
- float brakeDiscArea
- float tempCoeff
And then do some juggling like:
steadyStateTemp=brakingApplication*tempCoeff
if(temp<steadyStateTemp)
temp+=tempRiseCoeff*brakeDiscArea^2*brakingApplication*dt
else
temp-=tempFallCoeff*brakeDiscArea^2*(1-brakingApplication)*dt
Sort of like that, being creative as I write. :)
Ruud van Gaal
Free car sim: http://www.racer.nl/
Pencil art : http://www.marketgraph.nl/gallery/
You're an artist!
hehhe
I've found some stuff on a racing brake reseller about optimal
temperature... I'll try to use that...and be..hmmm.. creative..hehehe
I've learned how they check for brake temperature... with a special paint to
apply to the brakes! That's fun...
"Ruud van Gaal" <[email hidden]> wrote in message
news:[email hidden]...
Quoted text (43 lines)
> On 19 Feb 2002 08:30:21 -0800, [email hidden] (Stefano Casillo) > wrote: > > >Hi guys, > > > >I'm wondering if someone here is modelling Fx/Camber ... there's > >nothing about camber in longitudinal Pacejka... but I think that's > >plain wrong and Fx should decrease with camber... > > Hm, perhaps yes. You'd say with a lot of camber Fx would surely > decrease, since the contact patch gets smaller (less wide). > > But perhaps wasn't big enough to add to Pacejka? (hm, lots of tiny > things go into Pacejka, so you would say camber would be at least of > the same importance as many other coefficients). > > >Question 2: > > > >Any good links or SAE papers about brakes/temperature relations? > > I have no idea. However, I'd say it's a matter mostly of raising > temperature and lowering it based on braking power, where the relation > is quadratic (since we're dealing with an area, not really a volume > and certainly not a line). > So what I want to do in the future is: > - float tempRiseCoeff, tempFallCoeff > - float brakeDiscArea > - float tempCoeff > > And then do some juggling like: > steadyStateTemp=brakingApplication*tempCoeff > > if(temp<steadyStateTemp) > temp+=tempRiseCoeff*brakeDiscArea^2*brakingApplication*dt > else > temp-=tempFallCoeff*brakeDiscArea^2*(1-brakingApplication)*dt > > Sort of like that, being creative as I write. :) > > > Ruud van Gaal > Free car sim: http://www.racer.nl/ > Pencil art : http://www.marketgraph.nl/gallery/I didn't ever see any "good" models for camber grip effects, so I just did a
simple curve fit to some (not enough, of course) data... with radial tires
the lateral grip will be highest when the tire is leaning several degrees
into the direction of turn, so your function will also have to take into
account slip angle/slip ratio as well as camber. I think RCVD probably has
some sample graphs of this effect.
For temperature, wouldn't you want something like:
input_power = brake_torque * wheel_angular_velocity
energy = (air_temperature - temperature) * radiation_factor * airflow +
input_power
temperature += energy/(mass*specific_heat) * delta_t
(i.e., cooling/heating rate is proportional to the difference between object
and ambient temperature... constants thrown in as needed, as I just pulled
this out of thin air...)
"Ruud van Gaal" <[email hidden]> wrote in message
news:[email hidden]...
Quoted text (43 lines)
> On 19 Feb 2002 08:30:21 -0800, [email hidden] (Stefano Casillo) > wrote: > > >Hi guys, > > > >I'm wondering if someone here is modelling Fx/Camber ... there's > >nothing about camber in longitudinal Pacejka... but I think that's > >plain wrong and Fx should decrease with camber... > > Hm, perhaps yes. You'd say with a lot of camber Fx would surely > decrease, since the contact patch gets smaller (less wide). > > But perhaps wasn't big enough to add to Pacejka? (hm, lots of tiny > things go into Pacejka, so you would say camber would be at least of > the same importance as many other coefficients). > > >Question 2: > > > >Any good links or SAE papers about brakes/temperature relations? > > I have no idea. However, I'd say it's a matter mostly of raising > temperature and lowering it based on braking power, where the relation > is quadratic (since we're dealing with an area, not really a volume > and certainly not a line). > So what I want to do in the future is: > - float tempRiseCoeff, tempFallCoeff > - float brakeDiscArea > - float tempCoeff > > And then do some juggling like: > steadyStateTemp=brakingApplication*tempCoeff > > if(temp<steadyStateTemp) > temp+=tempRiseCoeff*brakeDiscArea^2*brakingApplication*dt > else > temp-=tempFallCoeff*brakeDiscArea^2*(1-brakingApplication)*dt > > Sort of like that, being creative as I write. :) > > > Ruud van Gaal > Free car sim: http://www.racer.nl/ > Pencil art : http://www.marketgraph.nl/gallery/On Wed, 20 Feb 2002 23:37:35 -0600, "Dave Pollatsek"
<[email hidden]> wrote:
the constant is the Thermic Capacity J.kg-1,K-1
J = Joule
Kg = kilogramme
K = Klevin degre ( 0 degre kelbin = -273.15� degre celsius ) , and NO
negative value, in universe u cant have colder stuff ;)
delta_U = variation of internal nrj
Q = heat
W = work exchange
delta_U = W + Q
C = dQ / dT ( J.K-1 )
c = 1/m . dQ / dT ( J.kg-1.K-1 )
Some value of c ( J.kg-1.K-1 )
Water : 4,1855.10^3
ice : 2,1.10^3
steam : 1,9.10^3
Aluminium : 0,92.10^3
Iron : 0,75.10^3
Air : 1.10^3
for more information search for
Thermodynamic ( Thermodynamique in French )
Calorimetry ( Colorimetrie in French )
have fun ;)
Sebastien TIXIER - Game Developer
Dynamics and Car Physics
http://www.eden-studios.fr
GPLRank Normal:-44.24 Monster:-124.44
