Literature review and fundamental approaches for vehicle and tire state estimation*

ABSTRACT

Most modern day automotive chassis control systems employ a feedback control structure. Therefore, real-time estimates of the vehicle dynamic states and tire-road contact parameters are invaluable for enhancing the performance of vehicle control systems, such as anti-lock brake system (ABS) and electronic stability program (ESP). Today's production vehicles are equipped with onboard sensors (e.g. a 3-axis accelerometer, 3-axis gyroscope, steering wheel angle sensor, and wheel speed sensors), which when used in conjunction with certain model-based or kinematics-based observers can be used to identify relevant tire and vehicle states for optimal control of comfort, stability and handling. Vehicle state estimation is becoming ever more relevant with the increased sophistication of chassis control systems. This paper presents a comprehensive overview of the state-of-the-art in the field of vehicle and tire state estimation. It is expected to serve as a resource for researchers interested in developing vehicle state estimation algorithms for usage in advanced vehicle control and safety systems.     

An adaptive hawkes process formulation for estimating time-of-day zonal trip arrivals with location-based social networking check-in data

Location-Based Social Networking (LBSN) services, such as Foursquare, Facebook check-ins, and Geo-tagged Twitter tweets, have emerged as new secondary data sources for studying individual travel mobility patterns at a fine-grained level. However, the differences between human social behavioral and travel patterns can cause significant sampling bias for travel demand estimation. This paper presents a dynamic model to estimate time-of-day zonal trip arrival patterns. In the proposed model, the state propagation is formulated by the Hawkes process; the observation model implements LBSN sampling. The proposed model is applied to Foursquare check-in data collected from Austin, Texas in 2010 and calibrated with Origin-Destination (OD) data and time of day factor from Capital Area Metropolitan Planning Organization (CAMPO). The proposed model is compared with a simple aggregation model of trip purposes and time of day based on a prior daily OD estimation model using the LBSN data. The results illustrate the promising benefits of applying stochastic point process models and state-space modeling in time-of-day zonal arrival pattern estimation with the LBSN data. The proposed model can significantly reduce the number of parameters to calibrate in order to reduce the sampling bias of LBSN data for trip arrival estimation.     

The “Mirror Flags”: Ship registration in globalised ship breaking industry

The incorporation of new international regulations is a rational way to avoid the use of substandard Asian ship-breaking yards. However, more restrictive regulations and agreements could lead to increase the proliferation of the use of third countries in connection with ship recycling industry. The new Open Registries provides ship-owners with legal loopholes in order to avoid strict national legislations and international rules, thus the “genuine link” disappears and the ship-owner’s responsibilities relax. Ship-breaking industry is a complex interconnected system with many important key actors, such as shipping companies, ship-owners, ship registries, brokers, and ship-breaking yards, all of which are discussed in this paper under the vision of a new global ship recycling policy, and focusing in those cases when a ship changes its flag state registration just before scrapping. This paper analyses the most common flags selected in order to send ships for scrapping. Empirical investigation to determine the relation between States and ship-breaking industry has been carried out using the multivariate statistic technic known as “Simple correspondence analysis”. The results show a relation between ship registry selection and ships that are about to end their lives, re-flagging solely for the purpose of scrapping. If we observe the evolution of the different flag states at the end of the ship’s life, we find incremented use of new open registers or “Mirror Flags”. General abuse of new registries in ship-breaking industry would lead to a ship-breaking industry without rules or transparent procedures, which could violate labour and environmental standards.     

水面无人艇集群系统研究

针对具有未建模动态、外部环境干扰及未知集群参考信号的欠驱动无人船（USV）集群跟踪问题,研究USV集群运动决策机制并提出有限时间集群跟踪控制方法。

首先,利用Lyapunov函数和人工势函数,结合集群虚拟参考船位置信息,构造速度导引的集群运动决策策略;然后,设计有限时间集总不确定观测器（FLUO）,对速度误差方程中包含的未知信息予以补偿;最后,设计基于FLUO的非奇异终端滑模（NTSM）集群跟踪控制方法（FLUO−NTSM）。

通过理论分析和仿真试验,证明系统在有限时间内稳定。

基于所提集群运动决策策略和FLUO−NTSM跟踪控制方法,USV可保持群集并实现精准路径跟踪。

     

Stochastic frontier analysis of excess access to mid-trip battery electric vehicle fast charging

This study aims to explore how factors including charging infrastructure and battery technology associate the way people currently charge their battery electric vehicles, as well as to explore whether good use of battery capacity can be encouraged. Using a stochastic frontier model applied to panel data obtained in a field trial on battery electric vehicle usage in Japan, the remaining charge when mid-trip fast charging begins is treated as a dependent variable. The estimation results obtained using four models, for commercial and private vehicles, respectively, on working and non-working days, show that remaining charge is associated with number of charging stations, familiarity with charging stations, usage of air-conditioning or heater, battery capacity, number of trips, Vehicle Miles of Travel, paid charging. However, the associated factors are not identical for the four models. In general, EVs with high-capacity batteries are initiated at higher remaining charge, and so are the mid-trip fast charging events in the latter period of this trial. The estimation results also show that there are great opportunities to encourage more efficient charging behavior. It appears that the stochastic frontier modeling method is an effective way to model the remaining charge at which fast-charging should be initiated, since it incorporates trip and vehicle characteristics into the estimation process to some extent.     

基于VHDL的有限状态机电路设计

有限状态机(FSM)及其应用技术是数字系统设计中的重要组成部分,基于VHDL的有限状态机设计已经成为EDA技术中的主要设计方法。论文通过对AD采样控制状态机的原理分析,介绍了基于VHDL平台的有限状态机的设计技术和实现过程。     

基于设计模式的内容管理系统"多站点发布"设计

设计模式对当代的面向对象程序设计技术做出了巨大的贡献，为开发人员带来了福音。通过设计模式，程序的结构比以往更为有效。在内容管理系统“多站点发布”的设计中通过引入设计模式并对模式进行组合和简单实现不仅提高了系统设计的可重用性也避免了过分的设计，最终达到了设计与解决问题之间的最佳平衡。     

船舶动力定位系统的一增广非线性观测器设计

滤波和状态估计在动力定位系统中起着非常重要的作用。本文在文献[1]的基础上，为船舶动力定位系统设计了一增广非线性状态观测器，其稳定性通过李亚普诺夫方法得到了证明。该非线性观测器的性能通过对一动力定位船舶模型的仿真得到了验证。     

一种新型五电平逆变器及其电容预充电方法

本文提出一种新型五电平并网逆变器,相比于其他五电平逆变器,在该逆变器中当输出电压为高电平时,电流只流经两个开关管,因此可以减小导通损耗。而且,本文提出了针对该逆变器的改进型调制策略,可以实现开关损耗的最小化。更进一步地,为了避免在启动时由于悬浮电容电压未达到额定电压而导致的部分开关管应力过大的潜在风险,本文提出了针对该逆变器的直流充电方法,可以保证给各个电容安全充电的同时,使得所有开关管的电压应力都不超过其正常运行时所承受的电压应力。通过实验,该新型五电平逆变器拓扑和电容预充电方法的可行性都得到验证。     

如何接受和配合港口国监督检查

主要介绍了PSC检查中发现的主要缺陷,怎样做好接受PSC检查的准备工作和PSC检查时应注意的问题。