Multi-sensor selection optimization and driver warning decision for dynamical virtual driving simulator

This article presents a framework for the design and development of a multi-sensor selection optimization mechanism for a driver assistance simulation system. The multi-sensor selection mechanism is formulated as an optimization problem and solved by integer linear programming. Both static and dynamic driving scenarios are considered in the formulation; where a static scenario denotes an off-line multi-sensor selection problem and a dynamic scenario denotes an online driving condition transformation problem. The objective function for determining an optimal set of sensors is in terms of guaranteed coverage, energy, bandwidth, and reliability of sensors. For different driving conditions, and driver commands, a selection algorithm is developed for identifying the environment around the vehicle and warning the driver. The selection algorithm and multiple-vehicle driving examples are successfully implemented in a virtual driving simulator.     

超导磁悬浮微飞轮系统设计与功耗分析

针对飞轮系统在高转速时功耗大的问题,设计了基于超导磁悬浮轴承的微飞轮系统样机,研究了超导磁悬浮轴承对飞轮系统功耗的影响.微飞轮系统采用超导磁悬浮轴承作为支撑机构,以平面直流无刷电机作为驱动装置,在保证超导轴承场冷高度和电机间隙的条件下设计真空系统,通过搭建飞轮能耗实验平台,对超导磁悬浮飞轮系统的功耗进行分析,并通过测试不同场冷高度下的飞轮系统降速曲线,研究场冷高度对超导磁悬浮轴承的摩擦损耗影响.实验结果表明,在同样功耗下飞轮转子的最高转速可达到33 000 r/min,在15 000 r/min时超导磁悬浮轴承的功耗仅为机械飞轮系统功耗的1/7,并可以通过增加场冷高度进一步减少系统功耗.超导磁悬浮技术可以满足飞轮系统高转速、低功耗的要求．     

一种用于非圆异形孔加工的电磁驱动机构及控制方法研究

研究了用于非圆异形孔加工的电磁驱动机构及控制方法。为了对镗杆施加径向随动作用力,研制了由电磁定子和电磁转子组成的回转式电磁驱动机构。当改变定子线圈中的控制电流时,可以改变电磁定子与电磁转子之间的电磁驱动力,进而带动镗刀做径向微位移。通过电磁驱动力在静态工作点附近的线性化,建立了电磁驱动力与控制电流之间的线性关系,分析了实现电磁驱动力同步控制的方法。对电磁驱动机构进行了动态模拟试验,试验结果表明,随着转子的转动,在转子与定子之间可以形成一个同步旋转的电磁驱动力,实现镗杆中心的径向可控微位移。因此采用本文提出的回转式电磁驱动机构加工非圆异形孔是可行的。     

磁控挤压油膜阻尼器转子系统动力特性试验研究

为了改善传统挤压油膜阻尼器动力特性不可控的不足，提出了一种通过电磁效应来控制挤压油膜阻尼器动力特性的新结构，在一个双盘柔性转子系统上测量了不同磁场强度条件下磁控挤压油膜阻尼器转子系统在非旋转状态下的传递函数、在恒定转速下的运动轨道以及在慢加速运行过程中的不平衡响应曲线。结果表明了这种新型磁控挤压油膜阻尼器不仅具有良好的特性可控性，而且在设计合理的条件下还能够显著地减小转子系统的振动，是一种被动和主动兼备、具有良好发展和应用前景的转子系统阻尼结构。     

基于磁力等效原理的刚性磁悬浮转子系统高精度在线动平衡

针对磁悬浮飞轮转子不平衡振动问题,提出了一种在线动平衡方法。其基于磁轴承控制作用力与转子不平衡离心力之间的等效原理,通过检测磁轴承的控制作用力解算转子不平衡校正质量。设计了零位移控制器,使转子绕几何轴旋转,此时磁轴承的控制作用力与控制电流呈线性关系,通过测量控制电流来准确获得磁轴承的控制作用力。该方法消除了传统方法由动力学模型过度简化带来的误差,尤其适用于强陀螺效应的扁平型刚性磁悬浮转子系统。实验验证了该方法的有效性,对提高磁悬浮转子系统的动平衡精度具有实际意义。     

基于超磁致伸缩驱动器的油膜轴承-转子系统的稳定性研究

以超磁致伸缩驱动器(GMA)油膜轴承-柔性转子系统为研究对象,计入轴承质量和转子刚度建立了包括GMA磁滞伸缩力模型在内的动力学方程,利用Routh-Hurwitz准则,推导了GMA油膜轴承所支承的单质量弹性对称转子系统的稳定性判据。考察了驱动GMA的反馈电流的相位角和电流大小、转子刚度、转子质量和轴承质量对系统失稳转速的影响。结果表明,反馈电流的相位角对系统失稳转速影响很大,存在一个最佳值,使系统的失稳转速最高,系统稳定性最佳,并随着反馈驱动电流和转子刚度的增大,失稳转速明显增大;随着转子质量的增加,系统的失稳转速也是增加的,而轴承的质量对系统的失稳转速影响不大。计算结果在GMA油膜轴承-转子系统整体建模方面有一定的意义。     

Research on Driver Fatigue Early Warning Method Based on ARM

Fatigue driving is one of the important reasons of road traffic accidents,fatigue driving is refers to the driver in a long time continuous driving or physical fatigue condition,and then come into being physiological and psychological function disorder. In order to overcome the limitation of single sensor in the fatigue test,aimed at the requirements of monitoring on the fatigue driving,this article designed an driver fatigue monitor system based ARM926EJ-S as a controller,it is used to determine the driver's fatigue and reduce the traffic acc ident. On the basis of fully considering the source correlation and complementary,it adopts the method of multi-source information fusion; by monitoring the pulse,heart rate,temperature of the human body,steering wheel grip strength to realized the fatigue level. The system of graphical interface adopts UCGUI. Finally,testing the main function modules of early warning system,the feasibility of the proposed early warning system is verified fusion.     

Analysis of magnetic field and levitation force characteristics for 3-DOF deflection type PM motors

The mechanism and characteristics of the electromagnetic radial force are important for motors with complicated structures. The three-dimensional analytical model of the air gap between the rotor and stator is established under rotor eccentricity conditions. Then, aiming at solving the unbalanced radial force problem with rotor static eccentricity, the air-gap flux density, radial electromagnetic force, and the comparisons of harmonic contents are calculated and presented based on FEA (Finite Element Analysis) and MATLAB simulation. Finally, the magnetic field model has been validated by experiments utilizing a prototype system. The results provide a theoretical guide for configuration design, optimization, and levitation control research on three degree of freedom deflection type motors.     

无轴传动控制系统滑模变结构观测器研究

针对无轴传动中矢量控制系统各运动单元驱动电机、转子磁链难以精确观测的问题,设计了一种基于滑模变结构理论的转子磁链观测器,并用李亚普诺夫理论证明了算法的收敛性.仿真结果显示,该方法有较高的转子磁链观测准确度,并对转子电阻的变化具有鲁棒性.     

Driver behaviour when using an integrated advisory warning display for advanced driver assistance systems

With the increasing amount of safety features that are being introduced in our vehicles, research on warning design has suggested that advisory warning information may benefit driving performance. This simulator driving study compared driver?s performance using an integrated advisory advanced driver assistance system (ADAS) display based on ecological interface design (EID) combined with critical warnings to three ADAS with warnings of a critical character only. Results show that drivers drove with safer distances to vehicles in front when they received combined advisory/critical warnings compared to critical warnings only. Further, participants maintained better lane positioning during both the critical and combined ADAS conditions compared to baseline driving. In addition, participants found the combined warnings made them more aware of the traffic situation than when driving with critical warnings only and that the display helped them notice potential dangers in the traffic environment. These results suggest that providing drivers with advisory ADAS information can be a good complement to the critical warnings found in vehicles today and that a combination of these warnings, if correctly designed, may benefit both driver performance and driver acceptance.     

The effects of brief visual interruption tasks on drivers’ ability to resume their visual search for a pre-cued hazard

Driver visual distraction is known to increase the likelihood of being involved in a crash, especially for long glances inside the vehicle. The detrimental impact of these in-vehicle glances may carry over and disrupt the ongoing processing of information after the driver glances back up on the road. This study explored the effect of different types of visual tasks inside the vehicle on the top-down processes that guide the detection and monitoring of road hazards after the driver glances back towards the road. Using a driving simulator, 56 participants were monitored with an eye tracking system while they navigated various hazardous scenarios in one of four experimental conditions. In all conditions, a potential hazard was visible 4–5 s before the driver could strike the potential hazard were it to materialize. All interruptions were exactly two seconds in length. After the interruption the potential hazard again became visible for about a half-second after which the driver passed by the hazard. The nature of the in-vehicle visual interruption presented to the participants was varied across conditions: (1) Visual interruptions comprised of spatial, driving unrelated, tasks; (2) visual interruptions comprised of non-spatial, driving unrelated, tasks; (3) visual interruptions with no tasks added; and (4) no visual interruptions. In the first three conditions drivers glancing on the forward roadway was momentarily interrupted (either with or without a task) just after the potential hazard first became visible by the occurrence of an in-vehicle task lasting two seconds. In the last condition (no interruptions) the driver could not see the potential hazard after it just became visible because of obstructions in the built or natural environment. The obstruction (like the interruption) lasted for two seconds. In other words, across all conditions the hazard was visible, then became invisible, and finally became visible again. Importantly, the results show that the presence of an interruption (as opposed to an obstruction) negatively impacted drivers’ ability to anticipate the potential hazard. Moreover, the various types of interruptions had differential effects on hazard detection. The implications of this study for the design of in-vehicle displays are discussed.     

高速行车状态下驾驶人应激反应能力研究

为减少驾驶人在高速公路行车时因应激反应失误而引发交通事故,基于动力定型理论,开发驾驶人应激反应训练系统并进行仿真实验研究。选用30名被试分别在4个高速公路中典型应激交通场景下进行,运用MP 150实时记录被试人员的心率参数,运用对数回归和相关性分析,研究应激反应能力与训练次数间的定量关系。结果表明:随着训练次数增加,驾驶人应激反应能力增强。驾驶人经过标准规定次数的训练,即可减缓应激状态下的心理紧张,提高应激反应准确性和速度。设计的系统及建立的训练次数标准,满足驾驶人应激反应能力训练需求,可增强驾驶人应激能力,减少此类交通事故发生。     

Beyond general behavioral theories: Structural discrepancy in young motorcyclist's risky driving behavior and its policy implications

While many studies examine the mean score differences of psychological determinants between heterogeneous driver groups, this study reveals a structural discrepancy in a causal behavioral framework. Using young motorcyclists (ages 18–28) as subjects, this study investigates the various roles of key influential factors in determining risky driving behavior. Multi-group analysis of structural equation modeling shows that age and gender are two factors that can effectively distinguish heterogeneous driver groups exhibiting different decision-making mechanisms in shaping their risky driving behaviors. When encountering undesirable traffic conditions, road rage can immediately increase male motorcyclists’ intentions to engage in risky driving behaviors; on the other hand, young female motorcyclists further calculate their perceived risk to determine whether to engage in risky driving behaviors. This result shows that there is a significant link between risk perception and traffic condition awareness for experienced drivers (ages 25–28), but not for younger drivers (ages 18–24). This finding shows that while well-developed theories such as planned behavior and risk homeostasis provide general frameworks to explain risky driving behavior, heterogeneous driver groups may exhibit structural discrepancies that reflect their various decision-making mechanisms. This suggests that, in addition to mean differences, understanding structural discrepancies among heterogeneous groups could help researchers identify effective intervention strategies.     

Speech and driving - solution or problem?

Besides travel-related information (speedometer, tachometer, fuel gauge, and so on), driver-related information (navigation devices, telephone calls, email and so on) is now an increasing feature of modern-day driving. In order to process this information and still be able to drive safely at the same time, an information management system in the vehicle would seem to be necessary. Speech interfacing offers a good solution as verbal interactions use resources that are not needed when driving. However, in practice, experiments have shown that verbal interactions may distract the driver from the primary task. It is thus crucially important that verbal interactions are designed in such a way that the 'driving' task remains the focus of attention for the driver     

Local traffic condition: improvement of a vehicle-based measurement approach

Advanced driver assistance systems (ADAS) can be designed to adapt to the driver?s current needs, for example, taking the traffic conditions in the immediate vicinity of the ego vehicle into account. This motivates the design of a system intended to measure the local traffic conditions in a way, which corresponds to the driver?s perception of traffic conditions. A new method of measurement is introduced. It is based on automotive sensor technology. A stochastic approach is employed to optimise and evaluate the relationship between the subjective measurements made by the driver and the objective measurements presented. To this end, the drivers? subjective ratings are taken as reference. The analysis presented here is based on simulation data. The outcomes show that the design of the developed simulation environment is applicable to this work. It is shown that the objective measures correspond to the driver?s subjective ratings. Thus, it is possible to estimate the driver?s perception of traffic conditions using a technical measurement. The algorithm in its presented form is appropriate to give an estimation, which can be used as an input parameter for ADAS.     

Psychological constructs in driving automation: a consensus model and critical comment on construct proliferation

As automation in vehicles becomes more prevalent, the call for understanding the behaviour of the driver while driving an automated vehicle becomes more salient. Although a variety of driver behaviour models exist, and various psychological constructs have been said to be influenced by automation, an empirically testable psychological model of automated driving has yet to be developed. Building upon Stanton and Young's model of driving automation, this article presents an updated model of interrelated psychological constructs. The proposed model was created based upon a systematic literature search of driving automation papers and a subsequent quantification of the number of reported links between a selected set of psychological constructs. A secondary aim of this article is to reach consensus in the use of psychological constructs regarding driving automation. Henceforth special attention is paid to resolving the issue of construct proliferation.     

Analysis of driver roles: modelling the changing role of the driver in automated driving systems using EAST

ABSTRACT

The purpose of this paper is to analyse the role of the driver within automated driving systems using the Event Analysis of Systemic Teamwork (EAST) method. We already know that as the level of automation increases within the driving task, the role of the driver shifts from that of an active operator (i.e. a driver driving) to more of a passive monitor (i.e. a driver monitoring). Task, social and information networks were constructed using the Hierarchical Task Analysis of Driving and evidence from driver verbalisations collected during a previous study to further explore the changing role of the driver using network analysis. A ‘broken links’ approach was conducted to show that momentary engagement in non-driving-related secondary tasks within an automated driving system can dramatically change the structure of driving system.     

Real-Time Verification of AI Based Rotor Position Estimation Techniques for a 6/4 Pole Switched Reluctance Motor Drive

This paper presents real-time verification of an artificial neural network (ANN) and adaptive neuro-fuzzy inference system (ANFIS) based rotor position estimation techniques for a 6/4 pole switched reluctance motor (SRM) drive system. The techniques estimate rotor position by measuring the three-phase voltages and currents and using magnetic characteristics of the SRM, with the aid of an ANN and ANFIS, in real-time environments. The rotor position estimating techniques are used in a high-performance sensorless variable speed SRM drive. A digital signal processor, TMS320F2812, executes the rotor position estimation. To verify the performance of the ANN and ANFIS based rotor position estimation techniques, a rotor position sensor is mounted with the drive system. The experimental results show that the ANN and ANFIS based rotor position estimation techniques provide good performance at different operating conditions.     

电磁悬浮飞轮转子系统的模态解耦控制

基于电磁悬浮飞轮转子系统的数学模型,首先提出了一种在高速下能够使电磁悬浮飞轮转子系统保持稳定运行的模态解耦控制方法,然后对这种方法的解耦效果以及控制的有效性进行了仿真分析,并与传统分散PD控制的性能进行了比较。结果表明提出的模态解耦控制方法可以实现对电磁轴承飞轮转子系统的转动模态和平动模态间的解耦,以达到对各个模态的刚度和阻尼进行独立调节,使电磁悬浮飞轮转子系统具有更好的动态性能和更强的抗干扰能力的目的。     

Longitudinal control behaviour: Analysis and modelling based on experimental surveys in Italy and the UK

This paper analyses driving behaviour in car-following conditions, based on extensive individual vehicle data collected during experimental field surveys carried out in Italy and the UK. The aim is to contribute to identify simple evidence to be exploited in the ongoing process of driving assistance and automation which, in turn, would reduce rear-end crashes. In particular, identification of differences and similarities in observed car-following behaviours for different samples of drivers could justify common tuning, at a European or worldwide level, of a technological solution aimed at active safety, or, in the event of differences, could suggest the most critical aspects to be taken into account for localisation or customisation of driving assistance solutions. Without intending to be exhaustive, this paper moves one step in this direction. Indeed, driving behaviour and human errors are considered to be among the main crash contributory factors, and a promising approach for safety improvement is the progressive introduction of increasing levels of driving automation in next-generation vehicles, according to the active/preventive safety approach. However, the more advanced the system, the more complex will be the integration in the vehicle, and the interaction with the driver may sometimes become unproductive, or risky, should the driver be removed from the driving control loop. Thus, implementation of these systems will require the interaction of human driving logics with automation logics and then an enhanced ability in modelling drivers’ behaviour. This will allow both higher active-safety levels and higher user acceptance to be achieved, thus ensuring that the driver is always in the control loop, even if his/her role is limited to supervising the automatic logic. Currently, the driving mode most targeted by driving assistance systems is longitudinal driving. This is required in various driving conditions, among which car-following assumes key importance because of the huge number of rear-end crashes.The increased availability of lower-cost information and communication technologies (ICTs) has enhanced the possibility of collecting copious and reliable car-following individual vehicle data. In this work, data collected from three different experiments, two carried out in Italy and one in the UK, are analysed and compared. The experiments involved 146 drivers (105 Italian drivers and 41 UK drivers). Data were collected by two instrumented vehicles.Our analysis focused on inter-vehicular spacing in equilibrium car-following conditions. We observed that (i) the adopted equilibrium spacing can be fitted using lognormal distributions, (ii) the adopted equilibrium spacing increases with speed, and (iii) the dispersion between drivers increases with speed. In addition, according to different headway thresholds (up to 1 second) a significant number of potentially dangerous behaviours is observed.Three different car-following paradigms are also applied to each of the experiments, and modelling parameters are calibrated and compared to obtain indirect confirmation about the observed similarities and differences in driving behaviour.