I am trying to model all the forces a car suspension could undergo, for this car game of mine.(adsbygoogle = window.adsbygoogle || []).push({});

I am using the pacejka model to model the tyre, so that's not important, but I do need to understand how a car would transfer its weight under load.

I am using the following to calculate the load on one tyre:

n = normal force for the full car

l_c = load due to roll on the y axis (y axis points perpendicular to the direction of the car)

l_s = load due to roll on the x axis (x axis points in the direction of the car)

h = 1.0m (height of the CG from the ground)

L = length from front to back wheel (positive)

W = width from left to right wheel (positive)

m = mass of car

a_x = instantaneous x acceleration

a_y = instantaneous y acceleration (well both of these are not perfectly instantaneous when simulated, they are integrated over time).

The CG for simplicity is assumed to be at exactly halfway between both wheels in both directions.

(tyre load on front left tyre)

l_c + l_s = n/4.0 - ((h * mass * a_x)/L)/2.0 + ((h * mass * a_y)/W)/2.0

I think there's something wrong here, but I'm not well versed enough to figure it out. I'm also having the problem of getting lateral acceleration of like 100 (almost 10G's), but this is likely a problem with my tyre model giving too much grip.

If anyone could tell me how to determine the amount of roll a car experiences when it turns that would be great! I got the idea for the above from this website:

http://www.dur.ac.uk/r.g.bower/PoM/pom/node16.html

which probably explains it better, but doesn't add the term that deals with lateral roll.

I am using SAE coordinates, so z is up, y is right, and x is forward.

If someone could point me to another place which also describes the physics of a car's suspension in depth, that would be helpful also. I am currently simulating just a spring at each wheel, but I have the feeling this is wrong

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# Car suspensions

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