At 07:50 PM 10/28/99 , Engstrom wrote:
>> Ignoring the transition component, you'd want something like:
>>
>> g_usage = sqrt((cur_lat/peak_lat)^2 + (cur_accel/peak_accel)^2)
>>
>Now, usage at any point in the run is calculated as the highest of three
>numbers.
> 1) Total G percentage - this number is the distance from the
> origin (or center of the friction circle) of the total Gs that
> the car is currently pulling divided by the distance from
> the origin of the edge of the friction circle that touches
> a line that runs from the origin through the total G point
> that the car is currently pulling.
Okay. I think the math for this would be the g_usage I gave above,
where you use the appropriate friction circle for your speed.
>
> 2) Maximum acceleration G percentage - this number is the
> longitudinal acceleration that the car is currently pulling
> divided by the maximum longitudinal acceleration that the
> car can pull. If the friction circle for a given speed was
> always a circle, then this percentage would always be less
> than or equal to #1 above. However, the friction "circle" for
> any given speed is actually a friction ellipse. This means
> that although you might only be pulling 90% of total Gs,
> you are accelerating at 95% of the maximum longitudinal
> acceleration. Since Geez doesn't know whether you want
> to pull max longitudinal Gs or max total Gs at this point on
> the course, it gives you the benefit of the doubt.
Interesting. I would think that #1 would handle the ellipse okay without
#2. _But_, where the engine gives out at a different point than the tires,
the ellipse may not be a proper ellipse... but actually flat on top. In
that case, you'd need some really fancy math, OR approximate it by maxing
in this term.
Byron, is that a proper explanation?
Brian
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