Vehichle simulations

[Sathersc]

Hey all,

I realize this is potentially a sensitive topic, but we're looking to set up simulations on handeling and vehicle dynamics. We're basically starting off with simulations based off the shock and damper chapter of RCVD, and were wondering what kind of experience other teams have had with these sort of simulations. Is it worth while? What sorts of parameters would be good to consider? What sort of outputs teams derive from their simulations? That sort of stuff.

We have a pretty good idea of how to set up our initial simulation for one wheel and expand it to a total vehicle, but I'm also curious in general as to other simulations teams run. Basically anything anyone wants to talk about simulations, not limited to just suspension systems is what I'm personally interested in.

[Sathersc]

Hey all,

I realize this is potentially a sensitive topic, but we're looking to set up simulations on handeling and vehicle dynamics. We're basically starting off with simulations based off the shock and damper chapter of RCVD, and were wondering what kind of experience other teams have had with these sort of simulations. Is it worth while? What sorts of parameters would be good to consider? What sort of outputs teams derive from their simulations? That sort of stuff.

We have a pretty good idea of how to set up our initial simulation for one wheel and expand it to a total vehicle, but I'm also curious in general as to other simulations teams run. Basically anything anyone wants to talk about simulations, not limited to just suspension systems is what I'm personally interested in.

[Jersey Tom]

It is definately worthwhile. I have been doing the same thing.. just doing as much out of RCVD as I see practical and useful. The results are very interesting.

[Chris Boon]

I believe it would be very useful if you have the time, the right person doing it and accurate data/figures. It must be said that if you feed rubbish in you get rubbish out.

Also I wouldnt use anyone elses model unless you are 100% completely satisfied that it is correct. I tried using an ADAMS model of our car that a person did for his thesis. After 4-5 months of pain and heartbreak I gave up trying to fix it and gave up with ADAMS altogether. ADAMS seems really high-tech and wizzbang but I dont really know if it is appropriate for our applications considering the time and effort it seems that it would take to build an accurate model and not error prone. Has anyone been able to get meaningful answers from an ADAMS model of their car?

I like the look of Solidworks and have heard that you can do some basic simulations with it. Can anyone confirm this? If it is possible I think this would be much more appropriate because teams make a full-car assembly in CAD anyway and it is pretty easy to convert things into Solidworks documents anyway. Also got a demo thing of a program call CarSIM or something like that the other day and was going to see what its like. Has anyone had a play around with it?

Pity for us in Australia that time is running out and the thought of simulations is beyond us for 06 cause the real things should be running soon,.... I hope. Maybe next year we can get someone looking into some serious simulations and get some worthwhile results back in return.

Cheers,
Chris

[Tony K]

OptimumG has a nice package coming out in the somewhat near future that has a direct SolidWorks interface. However, it probably won't be available within the confines of an FSAE budget.

ADAMS has the potential to be a very powerful program, but the top teams that I have seen use it with good results (Newman-Haas, Pratt & Miller, and Prodrive) have software engineers that write custom programming into the base software to tailor the program to their needs. I suppose if you had a very talented individual on your team you could work on doing this, but we don't have anyone like that on our team.

For our car, I start off with SusProg3D for the kinematics end which does a very good job at dealing with roll stiffness, weight transfer, and all of the other kinematics of the suspension given the correct inputs. After that, I use that data to determine what kind of damping curves I would like based on the bump / roll inputs to the dampers, pray that I have the correct piston in the damper to baseline with (or find a proper endmill in an extreme case), and play the shim dance game until our damper dyno spits out some reasonable curves. Then with the dampers and suspension set to what I think is reasonable, it's time for a quick spin around the parking lot with some data aquisition.

It takes a bit of practice to figure out what you're looking for in the first place and how to get there, but since I don't have a software engineer at my disposal, and would much rather get my hands dirty than compile massive amounts of code, it works out pretty well for me.