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Firstly, a multiple-step parameter identification method is proposed, based on the analysis of the characteristics of the Magic Formula tire model structure.Show citation Neural Network Identification of a Racing Car Tire Model Jianfeng Wang, 1 Yiqun Liu, 1 Liang Ding, 2 Jun Li, 2 Haibo Gao, 2 Yuhan Liang, 1 and Tianyao Sun 1 1 School of Automotive Engineering, Harbin Institute of Technology, Weihai, Shandong 264209, China 2 State Key Laboratory of Robotics and System, Harbin Institute of Technology, Harbin 150001, China Show more Academic Editor: Kamran Iqbal Received 03 Aug 2017 Accepted 16 Apr 2018 Published 29 May 2018 Abstract In order to meet the demands of small race car dynamics simulation, a new method of parameter identification in the Magic Formula tire model is presented in this work, based on an analysis of the Magic Formula tire model structure.A high-precision tire model used for vehicle dynamics simulation is established via this method.
It is difficult for students to build a high-precision tire model because of the complexity of widely used tire models such as Magic Formula and UniTire. ![]() In order to fully understand the difference between the two models, a two-degrees-of-freedom (2 DOF) vehicle model is established. The advantages, disadvantages, and applicable scope of the two tire models are discussed after comparing the simulation results of the 2 DOF model with the Magic Formula and intelligent tire model. Introduction The Formula Society of Automotive Engineers (FSAE) race cars higher speed and greater cornering acceleration make tire characteristics significantly influence the vehicles performance 1 3. In order to ensure the results of vehicle dynamics simulation are consistent with real vehicle tests, the tire model problem must be solved. It is necessary to build a mathematical model that can accurately express the tire force and moment characteristics 4. In 1954, Fiala conducted an analysis and performed various experiments pertaining to cornering characteristics and proposed a dimensionless formula of tire characteristics based on a simplified analytical tire model 5. Since then, the relationship between lateral forcealigning moment and side slip angle has been found. In 1986, Shape proposed a multispoke model, and its central feature is that the carcass flexibility is associated entirely with independently acting radial spokes. In 1991, Gim built a complete tire force characteristic formula based on three elementary springs, whose axes of symmetry are perpendicular to each other. In the early 1960s, Pacejka simplified the carcass deformation as a stretched string, and conducted extensive theoretical and experimental research pertaining to the mechanical characteristics of tires 10. ![]() Presently, the pneumatic trail is expressed by a cosine function, and aligning moment can be obtained by multiplying the lateral force with the pneumatic trail and adding the usually small residual moment. This further improved tire model is called the Magic Formula tire model 12. The contact pressure distribution was assumed to be uniform in the lateral direction and of arbitrary form in the vertical direction 13. Later, a combined slip semiempirical tire model was developed. On the basis of various tests and theoretical analyses, a nonlinear and non-steady state tire model was proposed. The model can accurately express the six-dimensional wheel force under complex tire motion inputs involving side slip, longitudinal slip, turn slip, and camber 14 16. Presently, the UniTire model is widely used in research on vehicle handling dynamics. The intelligent tire model is built on the basis of a neural network and has multi-input, multioutput, and self-adaptive abilities 17. Since then, many scholars have begun to research this high-precision and convenient intelligent tire modeling method. In this paper, the FSAE race car of the Harbin Institute of Technology Racing Team (HRT) is taken as a research object.
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