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A Maneuver-Based Threat Assessment Strategy for Collision Avoidance

SAE International Journal of Passenger Cars - Electronic and Electrical Systems

Jilin University, China-Yaxin Li, Bohua Sun, Jian Zhao, Bing Zhu
Beihang University, China-Weiwen Deng
  • Journal Article
  • 07-12-01-0003
Published 2019-08-22 by SAE International in United States
Advanced driver-assistance systems (ADAS) are being developed for more and more complicated application scenarios, which often require more predictive strategies with better understanding of the driving environment. Taking traffic vehicles’ maneuvers into account can greatly expand the beforehand time span for danger awareness. This article presents a maneuver-based strategy to vehicle collision threat assessment. First, a maneuver-based trajectory prediction model (MTPM) is built, in which near-future trajectories of ego vehicle and traffic vehicles are estimated with the combination of vehicle’s maneuvers and kinematic models that correspond to every maneuver. The most probable maneuvers of ego vehicle and each traffic vehicles are modelled and inferred via Hidden Markov Models with mixture of Gaussians outputs (GMHMM). Based on the inferred maneuvers, trajectory sets consisting of vehicles’ position and motion states are predicted by kinematic models. Subsequently, time to collision (TTC) is calculated in a strategy of employing collision detection at every predicted trajectory instance. For this purpose, safe areas via bounding boxes are applied on every vehicle, and Separating Axis Theorem (SAT) is applied for collision prediction…
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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

Jilin University, China-Pingping Lu
GAC Automotive Research & Development Center, China-Bo Wang, Hongshan Zha, Guoqi Zhong, Shijing Weng, Qin Li
  • 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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Uncertainty Analysis of High-Frequency Noise in Battery Electric Vehicle Based on Interval Model

SAE International Journal of Vehicle Dynamics, Stability, and NVH

Jilin University, China-Junhong Dong, Fangwu Ma
China Automotive Technology and Research Center Co., Ltd, China-Cansong Gu, Yaodong Hao
  • Journal Article
  • 10-03-02-0006
Published 2019-02-01 by SAE International in United States
The high-frequency noise issue is one of the most significant noise, vibration, and harshness problems, particularly in battery electric vehicles (BEVs). The sound package treatment is one of the most important approaches toward solving this problem. Owing to the limitations imposed by manufacturing error, assembly error, and the operating conditions, there is often a big difference between the actual values and the design values of the sound package components. Therefore, the sound package parameters include greater uncertainties. In this article, an uncertainty analysis method for BEV interior noise was developed based on an interval model to investigate the effect of sound package uncertainty on the interior noise of a BEV. An interval perturbation method was formulated to compute the uncertainty of the BEV’s interior noise. The sound absorption coefficient and transmission loss of the sound package were obtained through tests, and a statistical energy analysis model of the BEV was established. The acoustic loads of the BEV were tested and the interior noise of the cabin was analyzed under certain working conditions. Uncertain parameters were…
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Tire Side Force Characteristics with the Coupling Effect of Vertical Load and Inflation Pressure

SAE International Journal of Vehicle Dynamics, Stability, and NVH

Jilin University, China-Konghui Guo, Ping Chen, Nan Xu
China Automotive Technology and Research Center Co., Ltd., China-Fei Li
  • Journal Article
  • 10-03-01-0002
Published 2018-11-09 by SAE International in United States
The tire vertical load and inflation pressure have great influence on tire steady- and non-steady-state characteristics and, consequently, on the vehicle handling and stability. The objective of this article is to reveal the coupling effect of tire vertical load and inflation pressure on tire characteristics and then introduce an improved UniTire side force model including such coupling effect through experimental and theoretical analysis. First, the influence of the tire vertical load and inflation pressure on the tire characteristics is presented through experimental analysis. Second, the theoretical tire cornering stiffness and lateral relaxation length model are introduced to study the underlying mechanism of the coupling effect. Then, an improved UniTire side force model including the coupling effect of tire vertical load and inflation pressure is derived. Finally, the proposed improved UniTire side force model is validated through tire steady-state and transient data. The coupling effect of tire vertical load and inflation pressure on tire cornering stiffness and lateral relaxation length is decided by the variation of the half length of tire contact patch and the carcass…
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Real-Time Estimation of Radar Cross Section for ADAS Simulation

Jilin University, China-Xin Li, Weiwen Deng
Published 2017-03-28 by SAE International in United States
This paper proposes a Real-Time Estimation of Radar Cross Section for ADAS Simulation, aimed to enable math-based virtual development and test of ADAS. The electromagnetic scattering mechanism is firstly analyzed with targets to be typical objects in traffic. Then a geometric model is developed, in which the object surfaces are divided into multiple scattering zones corresponding to different scattering mechanism. According to different surface curvature radius and scattering mechanism, the scattering zones are approximately equivalent to plane, cylinder, sphere and so on. Using the ARD model based on an improved physical optics and diffraction theory, RCS value of a zone is estimated. Then the RCS of the object surface is obtained by vector superposition of all zones. Some typical simulation comparisons are carried out, which proves the practicability of our method.
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Linear Vehicle Model Identification Under Different Speed Based on ARMA Model

Jilin University, China-Yan Bai, Hsin Guan, Changfu Zong
University of Sunderland, UK-D.A. Crolla
Published 2012-04-16 by SAE International in United States
Vehicle model plays an important role during the development process of a new car chassis. There are 2 different ways to set up the vehicle mathematics model, one is set up based on understanding the system mechanism and the other is based on system identification technique. In this paper, the transfer functions of the vehicle at 100 km/h, including yaw rate to the steering angle and lateral acceleration to the steering angle, were identified. And then the transfer functions under other forward speed were derived through studying two degrees of freedom vehicle model equation. At last the identified model at different speed was used to analysis the stability of closed loop system from the classical control theory viewpoint.
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Two-Degree-of-Freedom Controller Design for Clutch Slip Control of Automatic Transmission

SAE International Journal of Passenger Cars - Mechanical Systems

Jilin University, China-Hong Chen
Jilin University, China; Yokohama National University, Japan-Bingzhao Gao
  • Journal Article
  • 2008-01-0537
Published 2008-04-14 by SAE International in United States
To improve shift quality of vehicle with clutch-to-clutch gear shifts, a two-degree-of-freedom controller, including a clutch pressure estimator, is designed for clutch control during the inertia phase of the shift process. The controller is designed based on a low order linear model which is derived from dynamics of the proportional pressure control valve and the vehicle drive line. Then the calculated controller is evaluated on the constructed nonlinear powertrain simulation model. Simulation results show that the rotational speed difference clutch can track the desired trajectory well, and shock can be reduced by designing suitable feedforward compensator.
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Virtual Instrument System of Measuring Automotive Wake Velocity Based on Hot-Wire Anemometer

Jilin University, China-Li-min Fu, Xing-jun Hu
Published 2003-10-27 by SAE International in United States
In order to reveal the wake structure's characteristics effectively and then provide the basis to improve the body shape, considering shortcomings of traditional test instruments we introduced the concept of virtual instrument, and developed a virtual instrument system based on hot-wire anemometer to measure automotive wake velocity in the automotive wind-tunnel by means of LabVIEW program. With this system we made an experiment to gain the wake velocity distribution behind one certain kind of passenger car made in China, and the results are in accordance with those of the former research, which validate the virtual instrument system.
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New Creation Method of Class-A Surface Model of Autobody

Jilin University, China-T. Ma, L. Yi, F. Lan
Published 2003-10-27 by SAE International in United States
In general smoothing and evaluating an autobody outer surface is very difficult for autobody designers, but it is a very important requirement in autobody design. This paper reviewed a lot relevant researches, expressed the definition of autobody Class-A surface, and presented a new method for modeling. Finally some design examples were demonstrated.
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