EN
    您的位置: 首页 > 研究成果 > 研究论文
 
按时间查看




Tire-Road Friction Estimation based on Frequency Characteristics of In-Wheel Electric Drive System
作者 Long Chen,Mingyuan Bian,Yugong Luo,Zhaobo Qin,Keqiang Li
出版年份 2015 引用
摘要
In-wheel drive systems which combine with the permanent magnet synchronous motors (PMSM) and tires are highly electromechanical-coupled. This paper studies the dynamic characteristics of...展开全文
In-wheel drive systems which combine with the permanent magnet synchronous motors (PMSM) and tires are highly electromechanical-coupled. This paper studies the dynamic characteristics of this system to estimate the tire-road friction condition. After a dynamic tire model and a PMSM model is studied, a transfer function from control signal of the motor to the wheel dynamics is obtained. As a result of analyses about longitudinal dynamics in the frequency domains, motor-wheel resonance frequency is observed, which is related to the tire-road friction. Based on this feature, the friction estimation method combining a system identification technique to find dominant resonance frequency and recursive least square filtering, is applied for simulation. The simulation result shows that the proposed approach can detect road friction in the case that the tire is freely rolling, which is not sensitive to the noise and error of wheel speed signal.
收起全文

V2I-based Startup Assistance System at Signalized Intersections
作者 Jianqiang Wang,Yougang Bian,Biao Xu,Hongmao Qin,Manjiang Hu,Bin Huang
出版年份 2015 引用
摘要
Traffic delays are caused by unskilled vehicle operation and driver distraction during the startup process at signalized intersections. To address this issue, we propose a V2I-based driver assistance ...展开全文
Traffic delays are caused by unskilled vehicle operation and driver distraction during the startup process at signalized intersections. To address this issue, we propose a V2I-based driver assistance system that can acquire the current traffic signal status and provide drivers with startup assistance. This article presents the proposed system’s architecture and an assistance algorithm, which contains two types of driver assistance methods: startup prompting and automatic startup control. The automatic startup control method, based on fuzzy logic control, is validated in simulation tests. We also implement startup prompting using a prototype system and validate its performance in field tests. The test results suggest that the proposed assistance algorithm can help drivers start up their vehicles with less delay, which will significantly improve traffic efficiency.
收起全文

Complexity Analysis of Green Light Optimal Velocity Problem: An NP-complete Result for Binary Speed Choices
作者 Yang Zheng,Shengbo Eben Li,Biao Xu,Keqiang Li,Jianqiang Wang
出版年份 2015 引用
摘要
The motion of ground vehicles in a signalized traffic can significantly affect the throughput and efficiency. This paper presents the complexity analysis of a known green light optimal velocity(GL...展开全文
The motion of ground vehicles in a signalized traffic can significantly affect the throughput and efficiency. This paper presents the complexity analysis of a known green light optimal velocity(GLOV) problem, i.e., using the traffic light timing information to find optimal speed profiles that can avoid idling at red lights and minimize the trip time. A mathematical model for GLOV is formulated for the signalized traffic network, and then its problem complexity is analyzed by polynomial-time reducing a known NP-complete problem, i.e., partition problem, into GLOV. The complexity analysis shows that GLOV with binary speed choices belongs to NP-complete, which means it cannot be numerically solved in polynomial time unless P=NP.
收起全文

B&B Algorithm-based Green Light Optimal Speed Advisory Applied to Contiguous Intersections
作者 Biao Xu,Fang Zhang,Jianqiang Wang,Keqiang Li
出版年份 2015 引用
摘要
Signalized intersections play important roles in transportation efficiency and vehicle fuel consumption. The upcoming signal information obtained by DSRC communication can be used for green ...展开全文
Signalized intersections play important roles in transportation efficiency and vehicle fuel consumption. The upcoming signal information obtained by DSRC communication can be used for green light optimal speed advisory (GLOSA) to design the optimal velocity profile of approaching vehicles, which benefits fuel economy and traffic efficiency. In this paper, the branch and bound (B&B) algorithm based GLOSA applying to contiguous intersections is developed, aiming to improve the fuel economy. Using a communication platform, field tests were conducted to verify the GLOSA algorithm. The tests results indicate that, in free-flow conditions, the GLOSA algorithm can decrease stop times and fuel consumption without sacrificing trip efficiency.
收起全文

A Reliability Assessment Framework for Cloud Applications
作者 Xiaowei Wang,Jens Grabowski
出版年份 2015 引用
摘要
Cloud computing enables users to use computing resources, platforms and applications with reduced deployment and maintenance cost. The reliability of cloud applications becomes one of the key c...展开全文
Cloud computing enables users to use computing resources, platforms and applications with reduced deployment and maintenance cost. The reliability of cloud applications becomes one of the key concerns of cloud service providers and users. Meanwhile, the deep dependency stack of layered cloud objects makes it challenging to evaluate the reliability of cloud applications. To tackle this problem, we propose a layered dependency graph-based reliability assessment framework. To verify our framework, we conduct an initial case study which shows its feasibility.
收起全文

Tire–road friction coefficient estimation based on the resonance frequency of in-wheel motor drive system
作者 Long Chen,Mingyuan Bian,Yugong Luo,Zhaobo Qin,Keqiang Li
出版年份 2015 引用
摘要
In this paper, a resonance frequency-based tire–road friction coefficient (TRFC) estimation method is proposed by considering the dynamics performance of the in-wheel motor drive system under ...展开全文
In this paper, a resonance frequency-based tire–road friction coefficient (TRFC) estimation method is proposed by considering the dynamics performance of the in-wheel motor drive system under small slip ratio conditions. A frequency response function (FRF) is deduced for the drive system that is composed of a dynamic tire model and a simplified motor model. A linear relationship between the squared system resonance frequency and the TFRC is described with the FRF. Furthermore, the resonance frequency is identified by the Auto-Regressive eXogenous model using the information of the motor torque and the wheel speed, and the TRFC is estimated thereafter by a recursive least squares filter with the identified resonance frequency.Finally,the effectiveness of the proposed approach is demonstrated through simulations and experimental tests on different road surfaces.
收起全文



  Copyright © 2019 www.hive-hnu.org All rights reseved. 版权所有: 湖南大学智能车辆课题组
通讯地址: 湖南省长沙市岳麓区 湖南大学 现代工程训练中心A栋 邮编:410082