Path Tracking for Autonomous Race Car Based on G-G Diagram

Currently, the autonomous driving technique is attracting increasing research focus from all over the world. Generally, the control systems of an autonomous vehicle include environment perception, path planning and path tracking control systems. In this paper, the path tracking control issue of the autonomous vehicle will be focused on. Few of the previous proposed path tracking controllers consider the vehicle driving and handling limit, which degenerates the potential of the autonomous vehicle to finish the desired path as quick as possible. To this end, this paper proposes a path tracking controller for autonomous vehicle, which aims at pushing it to the driving and handling limit. The limit dynamic performance of the autonomous vehicle is represented by the G-G diagram, which indicates the acceleration capability of the autonomous vehicle. The G-G diagram is obtained by phase portrait method and it is validated by a modified FSAE racing car. Finally, a path tracking controller based on the G-G diagram is proposed. The simulation validation results demonstrate the effectiveness of the proposed controller.     

Development of an errorable car-following driver model

An errorable car-following driver model is presented in this paper. An errorable driver model is one that emulates human driver’s functions and can generate both nominal (error-free), as well as devious (with error) behaviours. This model was developed for evaluation and design of active safety systems. The car-following data used for developing and validating the model were obtained from a large-scale naturalistic driving database. The stochastic car-following behaviour was first analysed and modelled as a random process. Three error-inducing behaviours were then introduced. First, human perceptual limitation was studied and implemented. Distraction due to non-driving tasks was then identified based on the statistical analysis of the driving data. Finally, time delay of human drivers was estimated through a recursive least-square identification process. By including these three error-inducing behaviours, rear-end collisions with the lead vehicle could occur. The simulated crash rate was found to be similar but somewhat higher than that reported in traffic statistics.     

Human driving data-based design of a vehicle adaptive cruise control algorithm

This paper presents a vehicle adaptive cruise control algorithm design with human factors considerations. Adaptive cruise control (ACC) systems should be acceptable to drivers. In order to be acceptable to drivers, the ACC systems need to be designed based on the analysis of human driver driving behaviour. Manual driving characteristics are investigated using real-world driving test data. The goal of the control algorithm is to achieve naturalistic behaviour of the controlled vehicle that would feel natural to the human driver in normal driving situations and to achieve safe vehicle behaviour in severe braking situations in which large decelerations are necessary. A non-dimensional warning index and inverse time-to-collision are used to evaluate driving situations. A confusion matrix method based on natural driving data sets was used to tune control parameters in the proposed ACC system. Using a simulation and a validated vehicle simulator, vehicle following characteristics of the controlled vehicle are compared with real-world manual driving radar sensor data. It is shown that the proposed control strategy can provide with natural following performance similar to human manual driving in both high speed driving and low speed stop-and-go situations and can prevent the vehicle-to-vehicle distance from dropping to an unsafe level in a variety of driving conditions.     

Development and validation of a Kalman filter-based model for vehicle slip angle estimation

It is well known that vehicle slip angle is one of the most difficult parameters to measure on a vehicle during testing or racing activities. Moreover, the appropriate sensor is very expensive and it is often difficult to fit to a car, especially on race cars. We propose here a strategy to eliminate the need for this sensor by using a mathematical tool which gives a good estimation of the vehicle slip angle. A single-track car model, coupled with an extended Kalman filter, was used in order to achieve the result. Moreover, a tuning procedure is proposed that takes into consideration both nonlinear and saturation characteristics typical of vehicle lateral dynamics. The effectiveness of the proposed algorithm has been proven by both simulation results and real-world data.     

基于自然驾驶数据的跨江大桥小客车跟驰特性研究

为明确跨江大桥的跟驰行为特征以及驾驶模式,在重庆菜园坝大桥展开了30位被试的小客车实车驾驶试验,使用华测航姿测量系统和前视碰撞预警系统Mobileye 630采集自然驾驶状态下汽车的连续行驶速度、车头时距和车头间距等数据。通过筛选得到了725条有效跟驰轨迹数据,对比分析发现跨江大桥与城市一般道路的跟驰行为存在一定差异性,明确了菜园坝大桥车头时距和车头间距的分布特征,并且对强跟驰(小于1.6 s)、过渡区间(1.6~2.6 s之间)以及弱跟驰(大于2.6 s)3种跟驰状态和驾驶人性别差异下的跟驰数据进行了分析。结果表明:桥梁段车头时距分布集中在1.6 s处,车头间距分布集中在18 m处;超过1/3的跟驰轨迹处于强跟驰状态,此状态下前车驾驶行为对跟驰车辆具有较强制约性;当车辆处于弱跟驰状态时,前车对于后车的约束性会随车头时距的增大而快速降低;过渡区间的设立更好地揭示了强/弱跟驰状态之间的转变并不是只有一个临界值,而是存在一个转换过程,并且其间车辆跟驰特性的变化与驾驶人本身的操作行为存在较大关联;驾驶人的性别差异对跟驰距离几乎没有影响,但男性驾驶人往往会采取更加冒险的驾驶行为,平均车头时距、车头间距以及相对速度均高于女性驾驶人。     

汽车驾驶员不安全行为评价分析

为稳步增强汽车驾驶的安全性,减少安全事故的发生,驾驶人员除了需要具备足够的应急应变能力之外,还需要做好安全行为习惯养成工作,形成良好的驾驶习惯。文章以汽车驾驶员不安全行为作出研究对象,在明确不安全行为表现的基础上,深刻分析影响汽车驾驶人员不安全行为的因素,在此基础上,制定合理的应对策略,旨在引导驾驶人员形成安全行为,以不断提升驾驶员的驾驶能力。     

考虑肌电信号的驾驶人弯道操纵行为分析

驾驶人是"人-车-路"闭环系统中的核心。近年来,研发人性化、个性化的汽车驾驶辅助系统逐渐成为行业热点。为了更加透彻地理解弯道驾驶行为特性,为弯道驾驶辅助系统提供功效评估与优化,提出了一种考虑肌电信号的驾驶人弯道行驶过程操纵行为分析方法。招募12名驾驶人在试验场标准路面上进行实车试验,其中包含6名专业试车师与6名普通驾驶人,要求驾驶人分别以30,40,50 km·h^-1的不同初速度驶入U形弯道并自由驾驶。试验过程中记录驾驶人颈部肌电信号数据和车辆运动状态数据,分析转弯行驶车辆侧向运动对不同驾驶能力的驾驶人生理体验的影响,同时进一步探讨不同类型驾驶人在不同入弯速度条件下颈部肌电信号与侧向加速度的关联差异特性。试验结果表明：相同工况下,专业驾驶人和普通驾驶人颈部肌电特征值存在显著差异,专业驾驶人颈部肌电信号特征与车辆侧向加速度呈现一定的线性关系;随着驾驶任务难度的增加,驾驶能力好的驾驶人能够较好地适应任务的变化,在进行纵侧向耦合操纵时能够较好地协调身体生理反应与车辆侧向运动保持较好的关联特性。研究成果为进一步探索并完善驾驶体验评价方法提供了新的研究思路,同时,可为汽车辅助驾驶系统功能设计与智能汽车行驶性能的用户体验测评提供技术支撑。     

Traffic safety culture of professional drivers in the State of Qatar

Professional drivers play a significant role within the traffic system of the State of Qatar. With developing infrastructure, the need for professional drivers is growing. However, knowledge is lacking about their perception of traffic safety. Therefore, this study investigates the personal acceptance of risky driving and suggested traffic laws among this specific group of drivers, in order to create understanding about their likelihood to commit certain risky driving behaviors and their resistance to the implementation of certain traffic laws. The aim of this study is to establish which personal attributes of professional drivers in Qatar could influence a high likelihood to commit risky driving behaviors, estimating which specific groups of professional drivers impose the highest risk to violate certain traffic laws. Results indicate that transportation mode, origin and years of driving experience are all personal attributes that have a significant impact on the professional driver's risk to commit risky driving behaviors and their opposition to the implementation of related traffic laws. Distressing results have been found for the high likelihood to violate speed in school zones and the high risk to be distracted by any type of phone use while driving, suggesting the need to put emphasize on these safety hazards during the training programs of professional drivers at professional driving schools in the State of Qatar.     

基于改进BB-BC算法的轮毂电机直驱赛车行驶策略优化

为了合理制定轮毂电机直驱赛车的行驶策略,缩短完赛时间,提出了基于改进BB-BC算法的策略优化方法.在分析传统BB-BC算法不足的基础上,通过引入混沌逻辑映射的方法,形成改进的BB-BC算法.利用Matlab/Simulink建立了轮毂电机直驱赛车整车优化模型并进行了实车验证,进一步对行驶策略进行优化研究.结果表明,改进...     

驾驶行为与驾驶风险国际研究进展

驾驶人在驾驶车辆的过程中总会面临由自身或外界条件所带来的或高或低的风险,即驾驶风险,通过对驾驶风险进行识别、分析及评估是对风险进行管理的有效对策,明确由人为因素（即驾驶人个体特征及驾驶行为）所带来的驾驶风险并对驾驶人进行安全管理尤为重要。为了全面了解各类危险驾驶行为和各种驾驶人群体的驾驶风险行为研究进展,对驾驶风险领域重点问题进行了总体概述。从驾驶人个体特征及驾驶行为的角度出发,探究了驾驶风险领域目前的研究现状,并利用科学知识图谱展示驾驶风险领域研究的发展进程与结构关系。通过Web of Science核心合集数据库获取了3 406篇在1986~2020年（截至2020年2月29日）间出版的驾驶风险研究相关英文文献,共涵盖8 684位作者及6 018个关键词,基于科学知识图谱对该领域文献进行梳理与分析。结果表明：驾驶风险领域的国外研究在驾驶人选择方面主要从年轻驾驶人、老年驾驶人、新手驾驶人及职业驾驶人的角度进行切入,重点围绕酒驾、药驾、分心驾驶及疲劳驾驶等主题开展研究。与国外研究相比,中国在分心驾驶、疲劳驾驶领域的研究相对丰富,而针对酒驾、药驾的研究试验手段较为单一,研究不够全面;在研究对象的选取上,有必要进一步增加老年驾驶人及新手驾驶人的深入研究,包括老年驾驶人适驾性评估与教育培训,以及新手驾驶人驾照分级制度的可行性探索。在研究方法方面,国外常见研究方法包括问卷调查、驾驶模拟器试验、实车试验以及自然驾驶研究等,而中国在自然驾驶研究领域尚未充分开发利用;未来应考虑多种方法相结合并从不同角度促进对驾驶行为及驾驶风险的全面理解。     

公务车驾驶员的行车安全影响分析及对策

安全是公务车服务工作的重中之重。随着道路上行驶车辆的不断增加,公务活动节奏的加快,公务车驾驶员的行车安全日益受到关注。本文从思想、心理、身体和外部的车、路等因素影响分析,并结合实际提出对策。     

考虑驾驶人风格的换道轨迹规划与控制（双语出版）

基于自动换道控制技术中融合个性化驾驶人风格的研究,建立考虑驾驶人风格的车辆换道轨迹规划及控制模型以提高换道规划控制模型对不同风格驾驶人的适用性,在保证安全性的基础上进一步满足驾驶人的个性化需求。首先通过问卷调查的方式采集得到了212份驾驶人风格量表数据,采用主成分分析法和K均值（K-means）聚类分析法将驾驶人按驾驶风格分为激进型、普通型和谨慎型,并通过驾驶模拟器试验采集不同风格驾驶人分别在自车道前车、目标车道前车和目标车道后车影响下的换道行为数据。然后对椭圆车辆模型进行改进,以描述不同风格驾驶人的行车安全区域,并据此构建3种典型工况下不同风格驾驶人的换道最小安全距离模型,结合驾驶舒适性约束、车辆几何位置约束以及不同风格驾驶人的换道行为数据,以换道纵向位移最短为目标,实现适应驾驶人风格的换道轨迹规划。最后以基于预瞄的路径跟踪模型作为前馈量,设计基于动力学的线性二次型最优（LQR）反馈控制器,通过调节控制权重矩阵实现3种工况下不同驾驶人风格的换道轨迹跟踪。PreScan和MATLAB/Simulink联合仿真结果表明：所设计的考虑驾驶人风格的换道轨迹规划及跟踪控制模型能够实现不同驾驶风格的自动换道轨迹规划及跟踪控制,可满足驾驶人个性化换道需求。     

Car driving at the limit by adaptive linear optimal preview control

The paper is concerned with modelling car drivers. The context of the work presented is explained. Then, previous research on the application of optimal linear preview control theory to driving road vehicles with only modest excursions from a straight-running equilibrium state is extended into the general large-lateral-motion arena. Optimal controls are found for steady-cornering trim states of an exemplary car at a given speed as a function of cornering effort, up to the practical limit. The manner in which the optimal controls change as the cornering vigour changes is discussed. Simulations of the virtual driver-controlled car are shown to demonstrate the closed-loop system following lateral path demands and the advantages of employing gain-scheduled adaptive control over a fixed-control scheme are demonstrated.     

Investigating characteristics of cellphone distraction with significance tests and association rule mining

Due to the escalating usage of cellphones, cellphone distracted driving remains one of the fastest-growing traffic safety problems. Two basic types of cellphone distractions are – talking (handheld or hands-free) and manipulating (texting, internet browsing, using apps for social networking, navigation, entertainment, etc.). To explore the association between the cellphone distraction type and characteristics of a driver, roadway, and vehicle, we used Fisher's exact test and association rule mining to analyze the data from ten different hour-long observation sessions performed both at intersections and on straight continuous segments. Among 3727 drivers observed, 22.1% were found distracted by cellphones. More drivers were involved in manipulating (12.8%) than talking on the phone (9.3%). The Fisher's exact test results show that intersections and the presence of passengers may be significantly associated with driver distraction type. This study makes a novel attempt to utilize association rule mining in cellphone distraction observation. A set of generated rules and their network visualization demonstrated how a specific group of characteristics can be related to cellphone conversation or manipulation through the measures of support, confidence, and lift. 'Peak hour', 'Absence of passengers', and 'Urban setting' are more likely to be associated with distracted driving than other characteristics. The results from association rules revealed that male drivers were found to be predominantly involved in cellphone manipulation during peak hours on urban segments than female drivers, and they were also largely involved in cellphone conversation during peak hours on the rural segment. Female drivers engaged in manipulating cellphones at the urban intersection during both peak and off-peak hours. In the rural area during peak hours, female drivers were manipulating at the intersection and were talking while driving on the continuous segment. Drivers aged '30–60 years' were found to be more associated with cellphone use compared to '<30 years' and '>60 years' age group. 'Passenger car drivers during peak hours' were more associated with manipulating cellphones than expected compared to any other collective group, whereas 'female passenger car drivers driving on continuous segment' were strongly associated with cellphone conversation. The detailed discussion of the findings from association rule mining will be useful for targeting a specific group of relevant characteristics in potential cellphone distraction reduction strategies.     

卫星定位数据驱动的营运车辆驾驶人驾驶风险评估模型

为了提高营运车辆驾驶人安全管理的精细化水平，合理地评估驾驶人驾驶风险程度，有的放矢地降低高风险驾驶人的事故率，基于卫星定位数据特点及驾驶行为与驾驶风险的相关关系设计26个驾驶行为特征参数。考虑到高速和非高速行驶时相同驾驶行为对驾驶风险的影响区别较大，根据23名营运车辆驾驶人的实测数据有针对性地筛选高速和非高速路段驾驶人风险评估指标，构建营运车辆驾驶人驾驶风险评估指标体系。然后，基于熵权法、独立性权系数法和Spearman相关系数法建立集成赋权法，确定各评估指标的权重。最后，雇佣40名营运车辆驾驶人进行实车试验以验证模型的合理性。结果表明：车辆速度和加速度方面的驾驶行为特征可以用于评估驾驶人的驾驶风险且评估效果较好，驾驶风险评估得分与实际交通冲突次数呈正相关关系，所建立模型可以较为准确地评估营运车辆驾驶人驾驶风险的高低，准确率达到77.50%，该模型在不同地区使用时，准确率存在一定的差异，但在容许范围之内，方法具有较好的鲁棒性。     

汽车驾驶员如何提高预防事故能力

汽车的工业化生产让越来越多的家庭拥有了汽车作为出行工具,并且这也让人们的生活质量有了本质性的提升。不仅仅是人们的生活终会用到汽车同时在一些其他行业的工作过程当中也需要利用汽车进行运输,汽车产品的需求量呈现出逐年增长的模式。与此同时在建设过程当中汽车的驾驶安全问题也受到了社会的广泛关注。本文将从汽车驾驶员对预防事故的能力方面着手对汽车事故的预防问题进行简要探讨,希望能够为更多的驾驶人员提供一些参考和借鉴,从而更加保证自身行驶的质量和安全。     

试论汽车驾驶员在安全驾驶中的问题

中国在过去几十年里发生了翻天覆地的变化,社会经济建设取得了重大成就,经济也实现了跨越式发展。目前人们的收入是非常可观的,所以人们有足够的经济支撑购买汽车,这也正是现如今汽车保有量不断增加的主要原因。任何事情都具有双面性,汽车为人们的出行提供了便利,但是其同样会造成交通安全事故,威胁人们生命健康安全。对于汽车驾驶员来讲,道路状况会影响汽车驾驶状态,但对其影响最大的是个人主观因素,即驾驶员驾驶过程中的状态以及心理素质水平的高低。本文主要论述驾驶员在安全驾驶中的问题,并就问题提出解决策略。     

融合预瞄与势场栅格法的紧急避撞驾驶人模型

紧急避障工况下的驾驶人操作具有响应快且动作幅值较大的特点，传统预瞄驾驶人模型已不能适应紧急避障工况的需求，故考虑实际避撞场景开发相应的驾驶人模型就显得尤为必要。针对此种状况，基于驾驶模拟器，结合紧急避撞工况实际驾驶人操纵数据，提出了一种融合预瞄与势场栅格法的紧急避撞驾驶人模型。首先针对紧急避撞工况下车辆运动特点，建立车辆横、纵向耦合非线性动力学模型，并给出其状态空间方程描述；其次，离线仿真分析紧急避撞系统特征，并结合线性二次型最优控制，建立最优曲率预瞄+跟踪误差反馈驾驶人模型；再者，基于紧急避撞工况下真实驾驶人经验转向行为数据，开发基于势场栅格法的驾驶人模型，为进一步提高驾驶人模型对避障行驶工况的适应性，将基于势场栅格法的驾驶人模型与最优曲率预瞄+跟踪误差反馈驾驶人模型进行融合，并基于Sigmoid函数实现两者输出的权重分配；最后，针对所提出的融合预瞄与势场栅格法的驾驶人模型，开展基于避撞台架的驾驶人在环仿真试验以及实车试验。研究结果表明：在紧急避撞工况下，对比最优曲率预瞄+跟踪误差反馈驾驶人模型，融合预瞄与势场栅格法的驾驶人模型输出的转向动作与实际驾驶人行为较为接近，可在保证避障安全性的前提下，兼顾避障路径跟踪精度与车辆行驶的稳定性。     

FSC赛车空气套件CFD优化设计

在满足FSC赛车设计规则要求前提下,对空气套件进行了结构优化设计,重点完成了赛车尾翼的优化设计和分析。利用CFD技术对赛车车身模型进行了外流场分析,并通过在赛车尾部加装不同间隙和攻角的尾翼,进行车身外流场模拟对比分析,研究尾翼在改善赛车气动特性方面的影响规律,研究确定了空气动力学装置在不同比赛项目时的调教策略。通过对比分析赛车车辆周围气流的压力分布和速度分布规律,研究高速赛车的负升力效果,对于提高赛车的操纵稳定性和安全性具有非常重要的意义,对于指导赛车尾翼的正确安装、确定尾翼在不同比赛项目时的调教策略有一定的指导意义。     

Real-time characterisation of driver steering behaviour

In recent years the application of driver steering models has extended from the off-line simulation environment to autonomous vehicles research and the support of driver assistance systems. For these new environments there is a need for the model to be adaptive in real time, so the supporting vehicle systems can react to changes in the driver, their driving style, mood and skill. This paper provides a novel means to meet these needs by combining a simple driver model with a single-track vehicle handling model in a parameter estimating filter – in this case, an unscented Kalman filter. Although the steering model is simple, a motion simulator study shows it is capable of characterising a range of driving styles and may also indicate the level of skill of the driver. The resulting filter is also efficient – comfortably operating faster than real time – and it requires only steer and speed measurements from the vehicle in addition to the reference path. Adaptation of the steer model parameters is demonstrated along with robustness of the filter to errors in initial conditions, using data from five test drivers in vehicle tests carried out on the open road.

Abbreviations: ADAS: advanced driver assistance systems; CG: centre of gravity; CAN: controller area network; EKF: extended Kalman filter; GPS: global positioning system; UKF: unscented Kalman filter