Using TTC data in adams

[jowen]

I'm trying to use the pacejka data that has been provided by Stackpole Engineering in Adams car. What is bothering me is that Adams complains that the Pky2 coefficient (load at which Ky reaches maximum value) can't be negative. It is possible to run a simulation if I change it to a positive value but the camber thrust is very high. About as high as the cornering stiffness. The tire I'm trying to simulate is Hoosier 18x6-10.

Do you guys have any experience to share regarding the use of TTC data in adams?

/Joakim Wennström
Luleå University of technology

[jowen]

I'm trying to use the pacejka data that has been provided by Stackpole Engineering in Adams car. What is bothering me is that Adams complains that the Pky2 coefficient (load at which Ky reaches maximum value) can't be negative. It is possible to run a simulation if I change it to a positive value but the camber thrust is very high. About as high as the cornering stiffness. The tire I'm trying to simulate is Hoosier 18x6-10.

Do you guys have any experience to share regarding the use of TTC data in adams?

/Joakim Wennström
Luleå University of technology

[Ben Beacock]

aha.. I love the search button http://fsae.com/groupee_common/emoticons/icon_smile.gif
I just ran into the same thing with a negative PKY2, but for Formula CarMaker. Did you end up finding a solution? I'm going to try changing both PKY1 and PKY2 to +ve but I'm going to have a look at the equations first.

Ben

[jowen]

Nice to finally get a reply =)

I've made a matlab program that plots the coefficients, and when I change the sign on PKY2 the whole curve flips. So obviously, PKY2 needs to be correct sign for the car to not steer in wrong direction i.e. positive lateral force for negative slip angle.

[Ben Beacock]

Does Adams allow the use of scaling factors?
since PKY1 is the slope(stiffness) and PKY2 is the load for the max value, I flipped the signs on both, then applied SCALE.LKY = -1 to flip it over. I still have to check what that does to PKY3 and see if that needs to be flipped as well. It at least gets me rolling and not flying off into space http://fsae.com/groupee_common/emoticons/icon_smile.gif