Modeling And Application Of Tire Overturning Moment Property

In recent years, multi-body dynamics software is applied more and more widely in thesimulation of vehicle dynamics. Tire model of high accuracy is necessary to accurate vehicledynamics simulation behavior. At the same time, tire model should have good extension.After years of hard work, various tire models that well used in vehicle dynamics simulationhave been established, including theoretical model, semi-empirical model and empiricalmodel. However, the model of tire overturning moment is simplified or ignored in most tiremodels, which results in some deviation in the simulation. Consequently, a model of tireoverturning moment with high accuracy is established based on its produce mechanism, thenextended to non-steady conditions and verified by test data. In addition, tire overturningmoment in wheel center is obtained based on tire loaded radius and embedded in CarSim toconduct fishhook simulation. This thesis has five chapters.Chapter one is the introduction. It mainly presents the background and significance ofthe thesis, tire mechanical behavior, and the research progressing of tire models home andabroad, finally proposes the main contents of the thesis.Chapter two establishes tire overturning moment model of contact patch center and themodel is verified by test data. Firstly, the produce mechanism of the overturning moment isfurther analysed. It is thought that the overturning moment is caused by the shift of theapplication point of vertical force that was influenced by two factors: the tire carcass lateraltranslation deformation yielded by lateral force and the carcass effective camber related withtire camber and lateral force, and the two factors have different influence on tire overturningmoment with the change of vertical load. Then it is emphasized that tire overturning momentis influenced by vertical load, camber angle and tire width. Thus a model of tire overturningmoment is established, and verified by test data. Finally, it is compared between the model oftire overturning moment in this thesis and MF tire model. The comparison results show thatthe model of tire overturning moment established in this thesis has higher accuracy than MF model, thus improved the application of tire model.Chapter three establishes tire overturning moment model of wheel center and the modelis extended to non-steady conditions. Firstly it presents the influence of vertical load, lateralforce and camber angle on tire loaded radius, then a model of tire loaded radius isestablished and identified by various test data, it verifies the accuracy and application of themodel. Then the model of tire overturning moment in the wheel center that applies to thenon-steady conditions subsequently is obtained by using overturning moment in the contactpatch center and tire loaded radius. The model results of both contact patch center and wheelcenter in non-steady conditions are verified by test data. The research results show that thesteady model of tire overturning moment can express the non-steady characters on conditionof non-steady inputs.In chapter four, tire overturning moment is applied to vehicle dynamics simulation.Firstly it introduces the connection method of tire model and CarSim software. Then themodel of tire overturning moment is embedded in CarSim. In order to investigate the effectof overturning moment and tire loaded radius on vehicle dynamics, vehicle fishhooksimulation with different overturning moment models is conducted. The comparisons figuresof vehicle behaviors between high accuracy model, simple model and model withoutoverturning moment are given. From the figures we can see that tire overturning momentand loaded radius have great influence on the vehicle dynamics, the tire overturning momentneeds to be considered for an accurate vehicle simulation.Chapter five is the conclusion of the paper, it summarizes the full text and points outthe future research direction.