Analysis And Prediction Of Tire Combined Longitudinal And Cornering Property

All kinds of tire theoretical models, empirical models and semi-empirical modelshave been applied in the simulation of vehicle dynamics. But these tire modelsincluding theoretical models, empirical models and semi-empirical models must bevalidated by tire test data. However tire tests are restricted by test equipment. Andthere are so many factors that may have a big effect on the tire tests, such as tiretypes, tire traveling velocity, vertical load, longitudinal slip and slip angle, etc. It isimpossible to conduct all the tire tests considering all the factors. So the tire modelswith the function of prediction will reduce the cost of tire test, cut the experimentalcondition restriction and shorten the automobile development cycle.The cornering and longitudinal property is an important part in tire research, andit is also a key part in vehicle dynamics. On the basis of theoretical study andexperimental analysis, a new model-ISC model is brought forward. This new modelrequires pure slip tire test data and partial combined slip tire test data. In this paper,the comparison to Combinator model has been made through modeling mechanicsand prediction. The two models both use pure test data to predict. However,compared with Combinator model, ISC model has two differences. On one hand, it isa cosine expression in Combinator model, but this expression is replaced by ellipsein ISC model. On the other hand, in addition to pure test data, ISC model still needsome combined data. It makes a revision compared to Combinator model.First, on the basis of the theory of combined longitudinal-slip and corneringbrush models in steady state conditions, this paper come to a theoretical formula,and this theoretical formula takes the tire carcass into consideration. Throughequivalently analysis, how the tire carcass affecting the tire bristle equivalent distribution stiffness is known.Second, it provides a theoretical basis to the following researches through theresearch of tire longitudinal and cornering property analysis under small slip.Third, it confirms the deviation again by the research and the simulation of theMF model in this paper. This article explains that how the deviation appears inCombinator model. In order to get longitudinal force in pure longitudinal slip andlateral force in pure lateral slip, this paper uses UniTire model. So this article takes abrief introduction of UniTire model.Fourth, it provides a theoretical basis to the following researches through theresearch of tire longitudinal and cornering property analysis under large slip.Finally, this paper introduces the "slip circle" concept and the concept is firstlyproposed in Combinator model. Under the same value of the total slip vector, thereis ellipse relationship between longitudinal force and lateral force regardless of slipstate of tire. Therefore, this test builds the expression of ISC model and makes theprediction and comparison based on the ‘Smithers’ data. The contents include: theprediction of Combinator model, the prediction of ISC model and the comparison.From the results, we can see: the prediction using ISC model is better thanCombinator model. The prediction result using ISC model is closer to the test data,especially in the combined slip under small side slip angle.