[ODE] Re: Simulating Wheels

[Steve Baker]

Nate W wrote:

>>Just tweaking it until it seems right isn't going to cut it.
> 
> 
> That assumes you're modeling the bumps and dips in the roads you drive on
> with similar accuracy.

Well - so long as the simulated road has bumps and dips of reasonable dimensions,
that'll be good enough.

> Seems to me that if you tweak it until it seems about right, then tweaking
> a parameter of the simulated car by 10% should give you a pretty good idea
> of how the handling will change in reality if you tweak a parameter on the
> car by 10%.

But how do I tweak it "until it seems about right" - if all I've got to go
on is the graphics?

When I added a stiffer rear anti-sway-bar to my car, I could feel the change
in the seat of my pants on the very first corner.  It felt like the outside
rear corner of the car was being pushed upwards.   However, if you watch two
cars take a corner - one with the sway bar mod and the other without it - you
can't *see* any difference at all.

However, the effect on the handling is spectacular - the amount of lateral G
forces you can achieve (I have an accellerometer to measure this) goes up by
almost 20%.

The problem is - if I can only look at the car - I don't get that 'seat of the
pants' feel.  How am I going to tweak the suspension model?   There are a bajillion
parameters...getting any one of them off by a large amount may not have a significant
effect until you do something like changing the spring stiffness.

It seems to me that measuring everything and plugging it into a robust math model
is the way to go.

---------------------------- Steve Baker -------------------------
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