Entity

Time filter

Source Type


Xiao L.,Defective Product Administrative Center | Gao F.,Beihang University
IEEE Transactions on Intelligent Transportation Systems | Year: 2011

In this paper, the practical string stability of both homogeneous and heterogeneous platoons of adaptive cruise control (ACC) vehicles, which apply the constant time headway spacing policy, is investigated by considering the parasitic time delays and lags of the actuators and sensors when building the vehicle longitudinal dynamics model. The proposed control law based on the sliding-mode controller can guarantee both homogeneous and heterogeneous string stability, if the control parameters and system parameters meet certain requirements. The analysis of the negative effect of the parasitic time delays and lags on the string stability indicates that the negative effect of the time delays is larger than that of the time lags. This paper provides a practical means to evaluate the ACC systems applying the sliding-mode controller and provides a reasonable proposal to design the ACC controller from the perspective of the practical string stability. © 2011 IEEE. Source


Xiao L.-Y.,Beihang University | Xiao L.-Y.,Defective Product Administrative Center | Gao F.,Beihang University
Journal of Central South University of Technology (English Edition) | Year: 2010

The effect of the information delay, which was caused by the nature of the distance sensors and wireless communication systems, on the string stability of platoon of automated vehicles was studied. The longitudinal vehicle dynamics model was built by taking the information delay into consideration, and three typical information frameworks, i.e., leader-predecessor framework (LPF), multiple-predecessors framework (MPF) and predecessor-successor framework (PSF), were defined and their related spacing error dynamics models in frequency domain were proposed. The string stability of platoon of automated vehicles was analyzed for the LPF, MPF and PSF, respectively. Meanwhile, the related sufficient string stable conditions were also obtained. The results demonstrate that the string stability can be guaranteed for the LPF and PSF with considering the information delay, but the ranges of the control gains of the control laws are smaller than those without considering the information delay. For the MPF, the "weak" string stability, which can be guaranteed without considering the information delay, cannot be obtained with considering the information delay. The comparative simulations further demonstrate that the LPF shows better string stability, but the PSF shows better string scalable performance. © Central South University Press and Springer-Verlag Berlin Heidelberg 2010. Source


Huang G.,University of Science and Technology Beijing | Wang Y.,Defective Product Administrative Center | Chen Y.,University of Science and Technology Beijing | Wang J.,University of Science and Technology Beijing
Advanced Materials Research | Year: 2012

This paper analyzed the automobile defects and its risk characteristics; the Event Tree Analysis (ETA) method was introduced to determine the risk flow route of automobile defects. According to the scattered of automobile, a risk forecast method based on the Weibull distribution is established. Based on the thousand vehicle breakdown number for risk probability forecast, propose a risk assessment model of automobile defect. The results indicate that on gathering actual failure data from after-sales service, the Weibull distribution model has a favorable applicability for forecasting risk possibility. Source


Xiao L.,Beihang University | Xiao L.,Defective Product Administrative Center | Gao F.,Beihang University
Chinese Journal of Mechanical Engineering (English Edition) | Year: 2010

For the constant distance spacing policy, the existing researches of the string stability focus on the single-predecessor information framework(SPIF) and predecessor-successor information framework(PSIF). The research results demonstrated that the string stability could not be guaranteed with the SPIF, and then the PSIF was proposed to resolve this string instability. But the issue, whether the string stability can be guaranteed when applying the PSIF, is still controversial. Meanwhile, most of the previous researches on the string stability were conducted without consideration of the parasitic time delays and lags. In this paper, the practical longitudinal vehicle dynamics model is built with consideration of the parasitic time delays and lags existing in the actuators, sensors or the communication systems. Secondly, the detailed theoretical analysis of string stability in frequency domain is conducted to demonstrate that the classical linear control laws can not ensure the string stability when applying both the symmetrical PSIF(SPSIF) and asymmetrical PSIF(APSIF). Thirdly, a control law, which adds the position and velocity information of the leading vehicle, is proposed to guarantee string stability for small/medium platoon, and the other control law, which adds the acceleration information of the controlled vehicle, is proposed to guarantee string stability for large platoon as well as small/medium platoon. Finally, the comparative simulation is conducted to confirm the conducted analysis and the proposed control laws. The conducted research completes the means to analyze the string stability in frequency domain, provides the parameters' reference for the design and implementation of the practical automatic following controllers, and improves the reliability and stability of the platoon of automatic vehicles. © 2010 Chinese Journal of Mechanical Engineering. Source


Gao F.,Beihang University | Xiao L.,Defective Product Administrative Center | Wang J.,Beihang University
Beijing Hangkong Hangtian Daxue Xuebao/Journal of Beijing University of Aeronautics and Astronautics | Year: 2010

Based on the vehicle longitudinal lag-delay dynamics model, the string stability and the control strategies for the automated platoon of vehicles were analyzed and studied. The vehicle longitudinal lag-delay dynamics model was built under consideration of the time delay and time lag. The sliding model controller and proportion integration differentiation(PID) controller were proposed based on the constant time headway policy. Then, the analysis of string stability for the two controllers were conducted based on the string stable policy and the related string stable conditions were obtained. The comparative quantitative analysis and simulations' analysis demonstrates that the PID controller is more robust against the time delay and time lag. Source

Discover hidden collaborations