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Lu, Pingping
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Improving Multi-Axle Vehicle Steering Coordination Performance Based on the Concept of Instantaneous Wheel Turn Center

SAE International Journal of Commercial Vehicles

GAC Automotive Research & Development Center, China-Bo Wang, Hongshan Zha, Guoqi Zhong, Shijing Weng, Qin Li
Jilin University, China-Pingping Lu
  • Journal Article
  • 02-12-02-0010
Published 2019-03-14 by SAE International in United States
A new concept of instantaneous wheel turn center (IWTC) is proposed to evaluate and improve multi-axle vehicle steering coordination performance. The concept of IWTC and its calculation method are studied. The index named dispersion of IWTC is developed to evaluate the vehicle steering coordination performance quantitatively. The simulation tests based on a three-axle off-road vehicle model are conducted under different vehicle velocities and lateral accelerations. The simulation results show that the turn centers of different wheels are disperse, and the dispersion becomes larger with the increase of vehicle velocities and lateral acceleration. Since suspension has important influences on vehicle steering performance, the genetic algorithm is used to optimize the suspension hard points and bushing stiffness, aiming at minimizing the dispersion of wheel turn centers (DWTC) to improve the vehicle steering coordination performance. The optimization results indicate that the suspension optimization can effectively reduce the DWTC and improve the vehicle steering coordination performance. The proposed wheel turn center method provides an index and tool for the suspension design and optimization in the pre-development phase of the…
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Friction Model for Real-Time Simulation of Powertrain Dynamics

SAE International Journal of Vehicle Dynamics, Stability, and NVH

China Automotive Technology & Research Center-Liang Xu
Jilin University-Hsin Guan, Haiyan Song, Pingping Lu
  • Journal Article
  • 10-02-01-0003
Published 2018-05-22 by SAE International in United States
Clutch friction modeling in powertrain system is the key to realize the real-time and accurate simulation of the powertrain system, and it will have a significant effect on the accurate simulation of the nonlinear characteristics of the powertrain system. Friction models can be divided into two categories: discontinuous friction models and continuous friction models. The approach of dealing with zero velocity discontinuity will affect the numerical stability of the real-time simulation in the discontinuous friction models. The smaller simulation step usually required by continuous friction models will reduce the efficiency of the simulation. Therefore, how to establish and select the friction model is one of the difficulties in the powertrain system modeling. In this article, with the standard of high computational efficiency and numerical stability, simulation research on typical friction model used in real time simulation has been done. At the same time, some friction models of them are improved. A real-time simulation model of the powertrain system is established and the selected friction models are applied to the clutch modeling. The simulation results show…
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The Research of Tire Mechanics at Lower-Speed for Interactive Developing

ASCL of Jilin University-Hsin Guan, Chunguang Duan, Pingping Lu, Jun Zhan, Yunting He
Published 2015-03-30 by SAE International in United States
With the development of computer and vehicle research to high frequency, the driving simulator plays an important role on vehicle research and pre-development. The driving simulator have already been used for research about human factors, advanced active system (ABS, ESP et al), the vehicle dynamics and intelligent transportation systems (ITS) et al. The crucial requirement for a driving simulator is that it should have realistic behavior. The realistic behavior base on high-fidelity dynamics models especially tire model. “Tire/road” model is of special importance model for its influence on vehicle performances. The forces for accelerating, braking and steering are all came from tire road contact. The simulator simulation faces all possible driving scenes as driving in the real word, like parking on the hill, stop and start again, sharp steering and sharp braking et al. From the research based on the ASCL driving simulator (State Key Laboratory of Automotive Simulation and Control, Jilin University, China), the vehicle couldn't stop completely and the vehicle shift easily on the braking operation. The depressed phenomenon came from the tire…
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The Quasi-Instantaneous Engine Output Torque Model Based on Indicator Diagram

ASCL of JLU-Chunguang Duan, Xu Liang, Pingping Lu, Hsin Guan
FAW of China-Biao Li
Published 2014-04-01 by SAE International in United States
High-quality dynamics model is one of the trends of vehicle dynamics model research and development. The engine generates high frequency excitation during operation, which may cause dynamic response in full vehicle. However, the widely-used internal-combustion engine model in vehicle dynamics simulation is steady-state model, which can't describe the fluctuation of engine drive torque along with the crankshaft angle. Consequently, this article concentrates on the modeling of instantaneous engine drive torque in order to improve the dynamic performance of the vehicle model.The paper has built the quasi-instantaneous engine model based on indicator diagram. To satisfy the requirement of real-time simulation, dynamically equivalent piston-connecting rod model is built and fast interpolation algorithm is researched. The linkage was simplified to spring and damper, and decoupled the piston translation and the crank rotation movements. Based on the C language to build simulation program, and embed it into complex vehicle model to simulate various conditions, the simulation results show that the engine model was able to export crankshaft speed, drive torque periodic fluctuation in 720 degrees of crankshaft rotation cycle…
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