Tyre combined operation of both longitudinal and lateral slip

[Yunlong Xu]

Hi guys, this might be a question that should be put into the TTC forum, but since that forum is not near as active as this one and also I'm not putting on any detailed tyre data from the TTC DVD, I think I'll ask for help here

I'm just wondering what you do for modelling combined operations of the tyres(say 0.15 slip ratio, 3degrees slip angle)

The MRA tyre model doesn't seem to give combined operation data and the SES Pajecka only gives the pure slip coefficients.

What do you guys do to solve this problem? Braking and turning at the same time may not be a too significant problem since our driver doesn't tend to do trail braking, but what about accelerating out of a corner? I'm sure tha't one of the most important factors in FSAE. With a good model for tyre characteristics in combine operation, it seems to me that it is impossible to predict the performance of a car out of a corner.

Any ideas? cheers

[Yunlong Xu]

Hi guys, this might be a question that should be put into the TTC forum, but since that forum is not near as active as this one and also I'm not putting on any detailed tyre data from the TTC DVD, I think I'll ask for help here

I'm just wondering what you do for modelling combined operations of the tyres(say 0.15 slip ratio, 3degrees slip angle)

The MRA tyre model doesn't seem to give combined operation data and the SES Pajecka only gives the pure slip coefficients.

What do you guys do to solve this problem? Braking and turning at the same time may not be a too significant problem since our driver doesn't tend to do trail braking, but what about accelerating out of a corner? I'm sure tha't one of the most important factors in FSAE. With a good model for tyre characteristics in combine operation, it seems to me that it is impossible to predict the performance of a car out of a corner.

Any ideas? cheers

[Zac]

The SES pacejka fit includes combined coefficients for some inflation pressures. There are a couple revisons of the document floating around. make sure you're looking at SES_FSAE_Tiredata_Round3_Rev1

Also, you could also fit to pacejka yourself(the equations are out there) or even develop your own force and moment model. Wasn't someone from OptimumG offering up a free Beta of their force and moment fitting software a couple months ago?

I think the only issue you will run into is that not all of the tires were run at every condition for every inflation.

[Yunlong Xu]

The tyre that we are using is AVON 7.2/20-13. I've only got the data from DVD of round 2 testings... Do we get the data of every new round as long as we've paid to join the TTC or do we need to pay for every round of data,ie 500/round? When we bought it , the dollars was a LOT cheaper...

[Zac]

I believe that once you're in the TTC, you're in for good.

But if you're using the Avon you'll be out of luck. Because of "availability issues," Avon hasn't been included on the past 2 rounds of testing (which actually includes combined testing).

[Yunlong Xu]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Zac:
I believe that once you're in the TTC, you're in for good.

But if you're using the Avon you'll be out of luck. Because of "availability issues," Avon hasn't been included on the past 2 rounds of testing (which actually includes combined testing). </div></BLOCKQUOTE>

Well, then I guess we'll swtich to other tyres next year. I always believe that we should use a tyre that we've got the most information of.

I've just downloaded the round 4 data off the TTC forum. And now I just need to make sure that I keep hassling our team leader till he gives me the round 3 data...

Thanks for your reply