Identifying multiclass vehicles using global positioning system data

It has been previously evidenced that global positioning system (GPS) data can be used to distinguish passenger cars from delivery trucks. In this paper, a machine learning approach is proposed to use GPS data to identify multiclass vehicles, including passenger cars, single unit trucks, and multi-trailer trucks. The method is acceleration and deceleration-based since it considers the variations of acceleration and deceleration as the most effective features to classify vehicles. The overall classification result for the three vehicle classes is about 75%. The major challenge is to distinguish single unit trucks from multitrailer trucks due to their somewhat similar mobility patterns. The paper also explores the impacts of GPS sampling frequency on vehicle classification. It is found that the proposed multiclass vehicle classification can be reasonably conducted if the data are collected frequently enough (i.e., every five seconds or more frequently) to capture the major acceleration and deceleration processes. The proposed method can be considered as a low-cost and non-intrusive approach to collect vehicle class information and to potentially supplement the existing classification schemes in urban areas.     

Smooth motion control of the adaptive cruise control system by a virtual lead vehicle

The adaptive cruise control system maintains the appropriate distance to the lead vehicle when the lead vehicle exists and maintains the desired speed when no lead vehicle is detected. A virtual lead vehicle scheme is introduced to make the switching between the speed control algorithm and the distance control algorithm unnecessary and simplify the structure of the control system. The speed and the position of the virtual vehicle can be decided by the control system according to the current situation. Smoother responses are achieved by the virtual lead vehicle scheme compared to the conventional mode switching scheme. This method is also shown to provide a good reaction for when a lead vehicle cuts in or out. A linear quadratic controller with variable weights is suggested to control the virtual lead vehicle. This scheme shows improved performance in terms of passenger comfort and fuel efficiency of the host vehicle.     

Fuzzy and adaptive fuzzy control for the automobiles’ active suspension system

Two typical criteria for good vehicle suspension performance are their ability to provide good road handling and increased passenger comfort. The main disturbance affecting these two criteria is terrain irregularities. Active suspension control systems reduce these undesirable effects by isolating car body motion from vibrations at the wheels. This paper describes fuzzy and adaptive fuzzy control (AFC) schemes for the automobile active suspension system (ASS). The design objective is to provide smooth vertical motion so as to achieve the road holding and riding comfort over a wide range of road profiles. The efficacy of the proposed control schemes is demonstrated via simulations. With respect to the optimal linear quadratic regulator (LQR), it is shown that superior results have been achieved by the AFC.     

Fuzzy and adaptive fuzzy control for the automobiles' active suspension system

Two typical criteria for good vehicle suspension performance are their ability to provide good road handling and increased passenger comfort. The main disturbance affecting these two criteria is terrain irregularities. Active suspension control systems reduce these undesirable effects by isolating car body motion from vibrations at the wheels. This paper describes fuzzy and adaptive fuzzy control (AFC) schemes for the automobile active suspension system (ASS). The design objective is to provide smooth vertical motion so as to achieve the road holding and riding comfort over a wide range of road profiles. The efficacy of the proposed control schemes is demonstrated via simulations. With respect to the optimal linear quadratic regulator (LQR), it is shown that superior results have been achieved by the AFC.     

智能车辆非结构化路面障碍检测

为在非结构化路面条件下进行有效障碍检测,提出一套利用雷达和图像进行一般障碍特征提取的算法和一种利用多层技术专门适用于负障碍检测的轮廓提取方法.然后讨论通过双传感器融合进行障碍物识别的方法和框架.最后通过实车试验验证整套检测算法的准确性和可靠性.     

Vehicle detection system design based on stereo vision sensors

Vehicle detection is a crucial issue for driver assistance system as well as for autonomous vehicle guidance function and it has to be performed with high reliability to avoid any potential collision. The vision-based vehicle detection systems are regarded promising for this purpose because they require little infrastructure on a highway. However, the feasibility of these systems in passenger car requires accurate and robust sensing performance. In this paper, a vehicle detection system using stereo vision sensors is developed. This system utilizes feature extraction, epipoplar constraint and feature matching in order to robustly detect the initial corresponding pairs. The proposed system can detect a leading vehicle in front and can estimate its position parameters such as the distance and heading angle. After the initial detection, the system executes the tracking algorithm for the vehicles in the lane. The proposed vehicle detection system is implemented on a passenger car and its performances are verified experimentally.     

基于站点群体聚集性客流的公交串车调度优化

为提升城市公交准点率、减少延误，解决车辆串车问题，研究基于站点群体聚集性客流的公交调度优化方法。以乘客出行意愿、乘车属性、到站规律等标识公交客流变化特征，以车辆载客限制、站点延误、到达率、下车率等描述串车形成场景。考虑准时性、客流需求、调控策略等约束，采用实时混合控制策略，实现车头时距偏差与乘客总行程时间最小的多目标优化。提出的公交串车调度方法，考虑到乘客到达率的不确定性，并通过调控公交车辆站点驻站时间以及路段平均行驶速度，可满足站点时段性群体聚集公交客流出行需求，防范潜在的公交串车。在模型求解上，考虑到双目标优化视角的差异性，运用超车规则对串车场景下的出站车辆重新排序，设计基于NSGA-II的求解算法，以拥挤距离标定序度关系，以精英策略获取新种群，改进交叉算子，并基于TOPSIS法对获取的Pareto解集择优。最后，以实际公交线路为例进行案例分析，结果表明：基于站点群体聚集性客流的公交串车优化调度模型，系统考虑了乘客乘车属性与车辆载客限制，能够输出最优的车辆滞站与车速调整方案，并且能运算得出车辆离站时间、车头时距偏差、准点率、乘客等待时间以及乘客行程时间等多项运营指标。优化前后对比表...     

Nonlinear ACC in Simulation and Measurement

In this paper an adaptive cruise control (ACC) of a convoy consisting of two passenger cars is designed and tested. For the ACC only on board sensors in the following vehicle are used, communication within the convoy or between the controlled vehicle and electronic systems on the roadside is not assumed. A laser scanner is applied for range measurements, derived from the complete vision data of the area in front of the car. Since the scanner provides the range only, a Kalman Filter is used to estimate the velocity and acceleration of the car. For controller design the concept of flat outputs in connection with the exact state linearization is applied. Moreover, the exact state linearization is combined with a sliding mode control. The control parameters are obtained by an optimization algorithm using optimal tracking formulation. The optimization also guarantees individual vehicle stability as well as string stability of the convoy. It is shown how the convoy is responding to disturbances resulting from initial errors or from velocity steps by the leading vehicle at lower speed in simulation and experiment.     

Nonlinear ACC in Simulation and Measurement

In this paper an adaptive cruise control (ACC) of a convoy consisting of two passenger cars is designed and tested. For the ACC only on board sensors in the following vehicle are used, communication within the convoy or between the controlled vehicle and electronic systems on the roadside is not assumed. A laser scanner is applied for range measurements, derived from the complete vision data of the area in front of the car. Since the scanner provides the range only, a Kalman Filter is used to estimate the velocity and acceleration of the car. For controller design the concept of flat outputs in connection with the exact state linearization is applied. Moreover, the exact state linearization is combined with a sliding mode control. The control parameters are obtained by an optimization algorithm using optimal tracking formulation. The optimization also guarantees individual vehicle stability as well as string stability of the convoy. It is shown how the convoy is responding to disturbances resulting from initial errors or from velocity steps by the leading vehicle at lower speed in simulation and experiment.     

山区双车道公路路线设计车型分类标准

为研究建立公路路线设计标准车型,通过对西部山区双车道公路的实地交通调查,并结合我国在用车型统计,建立了各类营运车辆车型参数数据库;在详细统计分析现有车型的尺寸、载质量和功率质量比分布规律的基础上,以满足85%的车型外廓尺寸和载质量为标准,采用双因素聚类分析方法对各种车型的功率质量比进行聚类分层计算,根据外廓尺寸相近的原则进行归并后,提出了山区公路路线设计车型的小型车、大型车外廓尺寸分类标准。在此分类基础上,研究了用于公路纵断面设计的载重汽车动力性能标准,通过大量实地观测资料和统计分析,提出了载重汽车上坡动力性能曲线,建立了速度折减量与坡度、坡长之间的关系曲线,以速度折减量作为公路纵坡和坡长的设计关键指标。     

Advanced vehicle dynamics of heavy trucks with the perspective of road safety

ABSTRACT

This paper presents state-of-the art within advanced vehicle dynamics of heavy trucks with the perspective of road safety. The most common accidents with heavy trucks involved are truck against passenger cars. Safety critical situations are for example loss of control (such as rollover and lateral stability) and a majority of these occur during speed when cornering. Other critical situations are avoidance manoeuvre and road edge recovery. The dynamic behaviour of heavy trucks have significant differences compared to passenger cars and as a consequence, successful application of vehicle dynamic functions for enhanced safety of trucks might differ from the functions in passenger cars. Here, the differences between vehicle dynamics of heavy trucks and passenger cars are clarified. Advanced vehicle dynamics solutions with the perspective of road safety of trucks are presented, beginning with the topic vehicle stability, followed by the steering system, the braking system and driver assistance systems that differ in some way from that of passenger cars as well.     

乘用车市场库存深度的研究

根据2005-2011年的狭义乘用车市场库存数据，以当期批发量和批发量的环比两个因素作为自变量，以当期库存占批发量的占比为因变量，运用回归分析建模，并推断出1998～2004年的乘用车库存数，最后估算出2011年年底乘用车市场的库存总量。针对乘用车市场现有库存深度的计算公式没有考虑季节性因素的偏差，采用滚动月均销量法修正偏差，计算表明最佳滚动月与当年销量增长率和库存增长率有关。     

Wear/comfort Pareto optimisation of bogie suspension

Pareto optimisation of bogie suspension components is considered for a 50 degrees of freedom railway vehicle model to reduce wheel/rail contact wear and improve passenger ride comfort. Several operational scenarios including tracks with different curve radii ranging from very small radii up to straight tracks are considered for the analysis. In each case, the maximum admissible speed is applied to the vehicle. Design parameters are categorised into two levels and the wear/comfort Pareto optimisation is accordingly accomplished in a multistep manner to improve the computational efficiency. The genetic algorithm (GA) is employed to perform the multi-objective optimisation. Two suspension system configurations are considered, a symmetric and an asymmetric in which the primary or secondary suspension elements on the right- and left-hand sides of the vehicle are not the same. It is shown that the vehicle performance on curves can be significantly improved using the asymmetric suspension configuration. The Pareto-optimised values of the design parameters achieved here guarantee wear reduction and comfort improvement for railway vehicles and can also be utilised in developing the reference vehicle models for design of bogie active suspension systems.     

Optimal control of motorsport differentials

Modern motorsport limited slip differentials (LSD) have evolved to become highly adjustable, allowing the torque bias that they generate to be tuned in the corner entry, apex and corner exit phases of typical on-track manoeuvres. The task of finding the optimal torque bias profile under such varied vehicle conditions is complex. This paper presents a nonlinear optimal control method which is used to find the minimum time optimal torque bias profile through a lane change manoeuvre. The results are compared to traditional open and fully locked differential strategies, in addition to considering related vehicle stability and agility metrics. An investigation into how the optimal torque bias profile changes with reduced track-tyre friction is also included in the analysis. The optimal LSD profile was shown to give a performance gain over its locked differential counterpart in key areas of the manoeuvre where a quick direction change is required. The methodology proposed can be used to find both optimal passive LSD characteristics and as the basis of a semi-active LSD control algorithm.     

基于车辆位置与速度特征的驾驶行为模式分类方法

精细车辆轨迹中包含连续的时间戳、位置，以及速度等信息。通过对车辆轨迹数据进行量化表达与挖掘分析，可以实现对车辆行为模式的分类。现有研究大多关注对位置的聚类，很少对车速、加速度等特征进行研究分析，而车速等是反映驾驶行为模式的重要特征。为了将轨迹多维信息纳入分析框架，研究了基于位置与速度特征的车辆轨迹行为模式分类方法。为克服现有行为模式分类方法的维度单一性，运用豪斯多夫轨迹距离算法计算出位置和速度特征的综合距离矩阵，针对豪斯多夫距离算法鲁棒性差的缺点，采用单向豪斯多夫距离90%分位值对算法进行了改进，降低噪声影响。同时，引入了车辆位置和速度来进一步提高分类的准确性，运用多次分层聚类算法依次对位置与速度轨迹图进行分类，得到车辆位置和速度上的行为模式。以HighD数据集为样本，提取了三车道上的行车轨迹，验证了基于速度与位置特征的车辆行为模式分类方法。结果表明:①本方法可以得到位置和速度的综合行为模式，聚类平均准确率达到94.8%，优于DBTCAN准确率89.3%和t-Cluster准确率86.4%；②基于换道模式轨迹偏移率曲线的分析，得到了4种互异的典型车辆换道模式。该方法可利用多维轨迹数据对行车模式进行分类及行为辨识，在车辆轨迹分类与不良行为辨识方面具有应用潜力。      

A New Control Approach for Platoon Operations during Vehicle Exit/Entry

A new platoon control concept is introduced, called Back Control, in which the controller of a given vehicle utilizes state information from the lead, preceding, and following vehicles, as well as the vehicle itself. Simulations are carried out on two non-steady state platoon operations - vehicle exit and vehicle entry from a platoon. A previously developed longitudinal controller is utilized as a reference to the proposed Back controller and a ride quality index is used to assess passenger comfort in these simulations. It is shown that the Back controller has advantages over the reference controller in these two operations and that it is therefore worth examining as a candidate controller of vehicular platoons, especially in non-nominal operations.     

车载移动变电站在吉图珲客运专线项目施工供电中的应用

采用固定变电站审批程序复杂、构筑物多、建设工期长,不能满足工程项目施工电力快速供应的需要,车载移动变电站克服了这些缺点。以吉图珲客运专线项目施工供电为背景,对车载移动变电站在吉图珲客运专线项目施工供电中的应用进行监测和分析。主要研究内容和结论如下： 1）通过研究车载移动变电站技术在吉图珲客运专线施工供电中的使用情况,证明车载移动变电站完全满足吉图珲客运专线施工需要; 2）与传统供电技术进行对比和分析,可以据此判定车载移动变电站技术在施工、使用过程中远优于传统供电技术; 3）车载移动变电站技术在吉图珲客运专线的成功使用,是符合当前快速施工建设需要的新技术,对未来施工供电具有指导作用。     

Possibilities to improve the ride and handling performance of delivery trucks by modern mechatronic systems

The ride and handling qualities of conventional delivery trucks are wores compared to modern passenger cars. However this vehicles have the power to drive as fast as passenger cars. Vehicle comfort and driving safety are mostly influenced by vertical accelerations and vehicle movements caused by pitch and roll motions. In the paper “Vehicle Dynamics with Adaptive or Semi-Active Suspension Systems – Demands on Software and Hardware” Wallentowitz and Ridlich have shown at AVEC'94 in which way tyre stiffness, shock absorber characteristics, spring stiffness and unsprung mass have an influence on vehicle comfort and active safety. They achieved these results by the theoretical analysis of a quarter-vehicle-model. Their examinations are extended in this paper on the model of a complete delivery truck. By the use of the multibody-simulation tool SIMPACK the road performance of a delivery truck will be analysed. Therefore a complex model of the vehicle has been built up in SIMPACK. Several computer simulations have been carried out to analyse the vehicle comfort and handling characteristics in different standard driving manoeuvres.Furthermore, the potential of improvements is shown by simulating different driving manoeuvres with the complete vehicle model by varying some vehicle characteristics such as tyre stiffness, shock absorber characteristics, spring stiffness and unsprung mass.In addition to that, simulations with models of unconventional spring- and damper-systems have been carried out to demonstrate the potential of improvements by the use of these systems. Two different controller algorithms for a semiactive and an active suspension system have been used an will be compared in this paper.     

A Study on Terrain-Surface Modeling and Searching Algorithms for Real-time Simulation of Off-Road Vehicles

Summary Terrain surfaces have to be modeled in very detail and wheel-surface contacting geometry must be well defined in order to obtain proper ground-reaction and friction forces for realistic simulation of off-road vehicles. Delaunay triangulation is one of the most widely used methods in modeling 3-dimensional terrain surfaces, and the T-search is a relevant algorithm for searching resulting triangular polygons. The T-search method searches polygons in a successive order and may not allow real-time computation of off-road vehicle dynamics if the terrain is modeled with many polygons, depending on the computer performance used in the simulation. In order to accelerate the searching speed of the T-search, a terrain database of triangular polygons is modeled in multi-levels by adopting the LOD (Level of Detail) method used in real-time computer graphics. Simulation results show that the new LOD-search is effective in shortening the required computing time. The LOD-search can be even further accelerated by introducing the NN (Neural Network) algorithm, in the cases where a appropriate range of moving paths can be predicted by cultural or geographical or empirical information of the simulated terrain, such as lakes, houses, etc. Numerical tests show that LOD-NN search almost doubles the speed of the original T-search.     

高速公路运输量研究

提出了高速公路运输量的统计方法,并以南京—上海高速公路为例,首次统计了中国高速公路的客运量、货运量、客运周转量、货运周转量以及客、货运输密度。研究表明:在南京—上海通道内,高速公路和铁路起着同样的关键作用;货运方面,高速公路和铁路运送货物价值相差很大,两者是互补性的,客运方面,高速公路客运量中个性化出行与铁路是互补性的,而群体性出行与铁路是替代性的。对高速公路上运行的车辆状况进行了分析,指出货运量主要是由四轴的半挂列车和两轴的单车完成的。客运中个性化出行的乘客占40%,车数占88%。