ROLL CENTER FORMULA HELP

[IceMan007]

Hi,

I'm working on a software program to calculate the front roll center of a NASCAR Nextel Cup race car. Does anyone know of a mathematical formula for this? I've done it by plotting it out on graph paper based on suspension measurments and I would like to be able to do it on the PC. I'll give you a free copy of the proram for your help.

Thanks in Advance

 

[GregLocock]

What sort of suspension?

I haven't worked out the formula as such, it would probably get very difficult to account for the correct quadrant in the sines and coses in a short long arm, for example.

You might want to look in the FAQ.



Cheers

Greg Locock

 

[red300zx99x]

I have such a formula. 2d or 3d?

 

[IceMan007]

The method I curretnly use is located here

http://www.stockcarproducts.com/pstech3.htm

Thanks

 

[GregLocock]

Yes, that's the usual method. What is the problem?

Cheers

Greg Locock

 

[IceMan007]

The problem is there is a mathematical formula that you can use to enter the measurements and come up with the answer to the roll center location. Plotting it on graph paper is not hitech. Unfortunately my Geometry and Agebra where in over 20 years ago and I haven't a clue where to start. I figured a suspension engineer would know these by heart but I guess I am mistaken. I have several Race car design and advanced race car math books but none of them give the formula for figuring the roll center.

 

[WilliamH]

IceMan,

I would suggest you confer with William C. Mitchell. He has software that does what you want and a whole bunch more. Do a Google search "William C Mitchell software". This man has been doing chassis software for years and has some very usefull, easy to use programs.

Will

 

[red300zx99x]

2d or 3d. 2d is easy, intersection of lines. 3d your dealing with planes more, but yeh 2d or 3d. Also what type of suspension and what are the given inputs, be happy to work this out over the bb

 

[NormPeterson]

Is this being written in a programmming language or is it a spreadsheet application? In any event, it has to be easier to separately work out the intermediate results and solve for the final answer in a separate step rather than solve for the end result directly from the basic inputs via a single massive equation (let alone perform the initial check/debug).

Is it correct to assume that the suspension is not necessarily symmetrical left side vs right in terms of link lengths and inclinations? That will determine how many independent inputs are necessary.

Norm

 

[IceMan007]

See my link above. I am aware that it will take several calculations to come up with the final answer. See the link posted above for the formula currently in use by using plotting and graph paper. Unequal length control arms is the most psopular type of stock car setup. I'm going to be writing the program in Visual Basic 6.0 but a spread sheet could easily be converted to Visual Basic. 2D is best.

Thanks for your consideration and Happy Holdiays to All

Paul

 

[BillyShope]

I use Excel's "solver" tool for a 2D solution. Just took a few minutes to set up. Not as "neat" as a direct solution (sometimes you have to insert another guess to "nudge" the iterations along), but I usually make a mistake when I have to wade through that much algebra.

 

[carnage1]

http://locost7.info/mirror/suspension.php

slark.zip
it is in a spreadsheet, is this what you are after?

 

[sreid]

I think you could use one of the Mechanical Linkage programs.