汽车运行状态远程监测系统开发

介绍了汽车运行状态远程监测系统的组成和开发情况。该系统通过车载子系统采集车辆运行过程中的状态参数信息,借助于移动通信技术和计算机通信网络传至监测中心,状态监测与故障预测服务子系统对这些参数进行分析,以达到对车辆运行状态实时监测与故障预测的目的。该系统可以及时发现汽车潜在的故障,并提供警示信息或技术服务,确保汽车具有良好的运行性能,从而防止车辆带＂病＂行驶,避免因车辆故障引起的交通堵塞和交通事故,有利于保障道路交通的畅通。     

State estimation in roll dynamics for commercial vehicles

Accurate lateral load transfer estimation plays an important role in improving the performance of the active rollover prevention system equipped in commercial vehicles. This estimation depends on the accurate prediction of roll angles for both the sprung and the unsprung subsystems. This paper proposes a novel computational method for roll-angle estimation in commercial vehicles employing sensors which are already used in a vehicle dynamic control system without additional expensive measurement units. The estimation strategy integrates two blocks. The first block contains a sliding-mode observer which is responsible for calculating the lateral tyre forces, while in the second block, the Kalman filter estimates the roll angles of the sprung mass and those of axles in the truck. The validation is conducted through MATLAB/TruckSim co-simulation. Based on the comparison between the estimated results and the simulation results from TruckSim, it can be concluded that the proposed estimation method has a promising tracking performance with low computational cost and high convergence speed. This approach enables a low-cost solution for the rollover prevention in commercial vehicles.     

Adhesion estimation at the wheel–rail interface using advanced model-based filtering

The railway industry in the UK is currently expanding the use of condition monitoring of railway vehicles. These systems can be used to improve maintenance procedures or could potentially be used to monitor current vehicle running conditions without the use of cost prohibitive sensors. This paper looks at a novel method for the online detection of areas of low adhesion in the wheel/rail contact that cause significant disruption to the running of a network, particularly in the autumn season. The proposed method uses a Kalman–Bucy filter to estimate the creep forces in the wheel–rail contact area; post-processing is then applied to provide information indicative of the actual adhesion level. The algorithm uses data that, in practice, would be available from a set of modest cost inertial sensors mounted on the vehicle bogie and wheel-sets. The efficacy of the approach is demonstrated using simulation data from a nonlinear dynamic model of the vehicle and its track interface.     

Railway vehicle performance optimisation using virtual homologation

Unlike regular automotive vehicles, which are designed to travel in different types of roads, railway vehicles travel mostly in the same route during their life cycle. To accept the operation of a railway vehicle in a particular network, a homologation process is required according to local standard regulations. In Europe, the standards EN 14363 and UIC 518, which are used for railway vehicle acceptance, require on-track tests and/or numerical simulations. An important advantage of using virtual homologation is the reduction of the high costs associated with on-track tests by studying the railway vehicle performance in different operation conditions. This work proposes a methodology for the improvement of railway vehicle design with the objective of its operation in selected railway tracks by using optimisation. The analyses required for the vehicle improvement are performed under control of the optimisation method global and local optimisation using direct search. To quantify the performance of the vehicle, a new objective function is proposed, which includes: a Dynamic Performance Index, defined as a weighted sum of the indices obtained from the virtual homologation process; the non-compensated acceleration, which is related to the operational velocity; and a penalty associated with cases where the vehicle presents an unacceptable dynamic behaviour according to the standards. Thus, the optimisation process intends not only to improve the quality of the vehicle in terms of running safety and ride quality, but also to increase the vehicle availability via the reduction of the time for a journey while ensuring its operational acceptance under the standards. The design variables include the suspension characteristics and the operational velocity of the vehicle, which are allowed to vary in an acceptable range of variation. The results of the optimisation lead to a global minimum of the objective function in which the suspensions characteristics of the vehicle are optimal for the track, the maximum operational velocity is increased while the safety and ride quality measures of the vehicle, as defined by homologation standards, are either maintained in acceptable values or improved.     

Semi-active suspension systems for railway vehicles using magnetorheological dampers. Part II: simulation and analysis

In this paper, the semi-active suspension system for railway vehicles based on the controlled (MR) fluid dampers is investigated, and compared with the passive on and passive off suspension systems. The lateral, yaw, and roll accelerations of the car body, trucks, and wheelsets of a full-scale railway vehicle integrated with four MR dampers in the secondary suspension systems, which are in the closed and open loops respectively, are simulated under the random and periodical track irregularities using the established governing equations of the railway vehicle and the modelled track irregularities in Part I of this paper. The simulation results indicate that (1) the semi-active controlled MR damper-based suspension system for railway vehicles is effective and beneficial as compared with the passive on and passive off modes, and (2) while the car body accelerations of the railway vehicle integrated with semi-active controlled MR dampers can be significantly reduced relative to the passive on and passive off ones, the accelerations of the trucks and wheelsets could be increased to some extent. However, the increase in the accelerations of the trucks and wheelsets is insignificant.     

Active yaw damper for the improvement of railway vehicle stability and curving performances: simulations and experimental results

To further increase passenger train comfort and handling performances, a mechatronic approach to the design of railway vehicles is necessary. In fact, active systems on board a railway vehicle allow to push design barriers beyond those encountered with just passive systems. The article deals with the development of an electro-mechanical actuator to improve the running behaviour of a railway vehicle, both in straight track and curve. The main components of the active system are a brushless motor and a mechanical transmission, used to apply a longitudinal force between the carbody and the bogie of the vehicle. The actuator is operated in force control. Different control strategies were developed for straight track running, where the aim is to increase the vehicle critical speed, and for curve negotiation, where the goal is to reduce the maximum values of track shift forces. A mathematical model of the railway vehicle incorporating the active control device has been developed and used to optimise control strategies and hardware set-up of the active device and to estimate the increase in operating performances with respect to a conventional passive vehicle. The active control device has then been mounted on an ETR470 railway vehicle, and its performances have been evaluated during in-line tests in both straight and curved tracks.     

Active yaw damper for the improvement of railway vehicle stability and curving performances: simulations and experimental results

To further increase passenger train comfort and handling performances, a mechatronic approach to the design of railway vehicles is necessary. In fact, active systems on board a railway vehicle allow to push design barriers beyond those encountered with just passive systems. The article deals with the development of an electro-mechanical actuator to improve the running behaviour of a railway vehicle, both in straight track and curve. The main components of the active system are a brushless motor and a mechanical transmission, used to apply a longitudinal force between the carbody and the bogie of the vehicle. The actuator is operated in force control. Different control strategies were developed for straight track running, where the aim is to increase the vehicle critical speed, and for curve negotiation, where the goal is to reduce the maximum values of track shift forces. A mathematical model of the railway vehicle incorporating the active control device has been developed and used to optimise control strategies and hardware set-up of the active device and to estimate the increase in operating performances with respect to a conventional passive vehicle. The active control device has then been mounted on an ETR470 railway vehicle, and its performances have been evaluated during in-line tests in both straight and curved tracks.     

An overview: modern techniques for railway vehicle on-board health monitoring systems

Health monitoring systems with low-cost sensor networks and smart algorithms are always needed in both passenger trains and heavy haul trains due to the increasing need for reliability and safety in the railway industry. This paper focuses on an overview of existing approaches applied for railway vehicle on-board health monitoring systems. The approaches applied in the data measurement systems and the data analysis systems in railway on-board health monitoring systems are presented in this paper, including methodologies, theories and applications. The pros and cons of the various approaches are analysed to determine appropriate benchmarks for an effective and efficient railway vehicle on-board health monitoring system. According to this review, inertial sensors are the most popular due to their advantages of low cost, robustness and low power consumption. Linearisation methods are required for the model-based methods which would inevitably introduce error to the estimation results, and it is time-consuming to include all possible conditions in the pre-built database required for signal-based methods. Based on this review, future development trends in the design of new low-cost health monitoring systems for railway vehicles are discussed.     

Heavy duty vehicle rollover detection and active roll control

This paper presents the results of a comprehensive study on heavy-duty vehicle (HDV) roll stability improvement technology. The proposed rollover threat warning system uses the real-time dynamic model-based time-to-rollover (TTR) metric as a basis for online rollover detections. Its feasibility for implementation in a HDV rollover threat detection system is demonstrated through vehicle dynamic simulation studies. The research on the development of a rollover threat detection system is further enhanced in combination with an active roll control system using active suspension mechanism to improve heavy-duty trucks’ roll stability both in the static cornering and in emergency maneuvers. It has been demonstrated that the roll stability of typical heavy-duty trucks has been largely improved by the proposed active safety monitoring and control system.     

Prediction of Wheel/Rail Profile Wear

The alteration in wheel and rail profiles due to wear involves considerable vehicle and track-maintenance costs, and influences the loading capacity of the rails, as well as the operation safety and riding comfort of the vehicles. In the past twenty years a vehicle dynamics, contact mechanics and tribology based research work has emerged which is also recently continuous in an international scale, and this research is more and more intensive. Parallel to the growing possibilities of computer based analyses, several algorithms and numerical procedures have been elaborated, as well as measurement based experiments have been carried out to establish the reliable prediction of wear-caused wheel and rail profile alterations and to maximise the mileage performance by selecting the optimum vehicle system parameters for running gears operating on a selected railway line or a whole network under specified -in general inherently stochastic - traffic conditions. This paper takes an attempt to introduce the extended sphere of problems of wheel and rail wear prediction, as well as the latest results reflecting the present state of the art.     

GPRS道路实时监控系统的安全策略

GPRS道路实时监测系统直接监测试验车辆的运行状态及车辆的试验数据,系统能否安全稳定运行对试验结果意义重大。因此系统数据传输的安全性是一个至关重要的问题。     

面向交通枢纽的车辆三维真实感实时仿真

为分析和解决城市交通拥挤问题并提高城市道路利用率提供可行的途径,提出了一种面向交通枢纽的车辆运行仿真方法,通过场景、道路与车辆的三维动态建模,实现交通枢纽交通状况的实时真实感仿真.首先,提出了基于道路关键点连接网络模型表示交通枢纽的通行道路.其次,基于粒子系统实现车辆的动态运行实时仿真,并采用基于空间剖分的车辆碰撞检测方法对车辆运动控制算法进行了优化.最终,通过对路段的动态观测和反馈机制实现车辆行驶路线的规划和调度.实验结果表明,本文提出的方法可以生动直观地呈现实际路面的交通状况,并且能以较为流畅的帧速率实现交通场景的动态仿真.     

纯电动物流车用PMSM降开关损耗控制

物流车是城市内部运送货物的重要交通工具,具有运行距离短、启停频率高、运行时间长的特点。城市内部物流车都逐步采用纯电动物流车代替传统的燃油车。针对物流车运行特点,文章对电动物流车电机控制算法进行优化,在考虑不同工况下使用不同的开关频率,降低开关损耗,减少控制器发热。通过对降低开关损耗控制方法与传统控制方法在不同车辆运行工况下对比,电机控制器发热均有所降低,同时电机控制器效率有所增加。     

Semi-active suspension systems for railway vehicles using magnetorheological dampers. Part I: system integration and modelling

In this paper, it is aimed to investigate semi-active suspension systems using magnetorheological (MR) fluid dampers for improving the ride quality of railway vehicles. A 17-degree-of-freedom (DOF) model of a full-scale railway vehicle integrated with the semi-active controlled MR fluid dampers in its secondary suspension system is proposed to cope with the lateral, yaw, and roll motions of the car body, trucks, and wheelsets. The governing equations combining the dynamics of the railway vehicle integrated with MR dampers in the suspension system and the dynamics of the rail track irregularities are developed and a linear quadratic Gaussian (LQG) control law using the acceleration feedback is adopted, in which the state variables are estimated from the measurable accelerations with a Kalman estimator. In order to evaluate the performances of the semi-active suspension systems based on MR dampers for railway vehicles, the random and periodical track irregularities are modelled with a uniform state-space formulation according to the testing data and incorporated into the governing equation of the railway vehicle integrated with the semi-active suspension system. Utilising the governing equations and the semi-active controller developed in this paper, the simulation and analysis are presented in Part II of this paper.     

针对铰接工程车辆的变角度全景环视系统研究

针对铰接工程车辆车头与车厢间存在铰接角度且车身长导致的视觉盲区大的问题，提出了一种可以根据铰接角度实时调整拼接图像的变角度全景环视系统。对于静态俯视图像的生成，提出一种用于将畸变图像转换为俯视图像并对齐到指定位置的查找表快速映射方法，实现了通过一步变换完成鱼眼校正、逆透视变换与图像配准，提升了静态俯视图像生成的速率。对于动态全景环视图像的生成，提出了一种根据铰接角度改变后对应的动态查找表直接生成变角度全景环视图像的方法，提升了角度改变时图像重新配准的速率。对于全景环视图像的融合，提出了一种循环颜色调整和透明度融合相结合的方法，从而对整幅变角度全景环视图像进行均衡化处理并降低拼接缝带来的图像损失。试验结果表明：在同样的硬件平台下，对于静态俯视图像的生成，该系统不仅将运行速度提升了接近1倍，并且有效减少了图像的失真程度；在图像融合方面，该系统不仅获得了较好的融合效果，并且保证了运行的实时性；通过实车验证，该系统可以生成全局均衡且无缝的变角度全景环视图像并在嵌入式处理器上实现了接近30 帧·s^-1的处理速度；该系统实时生成的变角度全景环视图像可以有效消除铰接工程车辆周围的视觉盲区，从而提升铰接工程车辆行驶的安全性和便捷性。     

液压互联悬架抗侧倾控制研究（双语出版）

针对车辆减少能量消耗与提高抗侧倾能力需求,提出了一种主/被动可切换的液压互联悬架抗侧倾控制方法。基于9自由度车辆动力学模型,考虑蓄能器、液压缸、液压泵三者之间耦合的体积-流量-压力特性,建立液压互联悬架主动控制时域模型;结合"车身侧倾角-车身侧倾角速度"相平面法及车辆侧向加速度,得到车辆侧倾稳定域,并提出液压互联悬架系统侧倾稳定性控制介入与退出判据;在此基础上,采用Backstepping非线性控制算法设计主动液压互联抗侧倾控制器。最后,分析并改进侧倾稳定性评价指标,通过在MATLAB/Simulink环境下进行高速双移线、鱼钩试验等极端工况数值仿真,验证所提出的液压互联悬架主/被动切换控制系统能在减少能量消耗的情况下能否提高车辆抗侧翻的能力。研究结果表明：所提出的控制系统能有效提高车辆抗侧翻能力;当车辆侧倾状态超出设定的侧倾稳定区域介入线时,液压互联悬架系统由被动模式切换为主动抗侧倾模式,控制车辆侧倾状态回到稳定区域,以提高车辆侧倾稳定性;当判定车辆侧倾状态满足主动控制退出条件时,液压互联悬架系统回到被动模式,以减小能量消耗。     

Prediction of Wheel/Rail Profile Wear

SUMMARY

The alteration in wheel and rail profiles due to wear involves considerable vehicle and track-maintenance costs, and influences the loading capacity of the rails, as well as the operation safety and riding comfort of the vehicles. In the past twenty years a vehicle dynamics, contact mechanics and tribology based research work has emerged which is also recently continuous in an international scale, and this research is more and more intensive. Parallel to the growing possibilities of computer based analyses, several algorithms and numerical procedures have been elaborated, as well as measurement based experiments have been carried out to establish the reliable prediction of wear-caused wheel and rail profile alterations and to maximise the mileage performance by selecting the optimum vehicle system parameters for running gears operating on a selected railway line or a whole network under specified -in general inherently stochastic - traffic conditions. This paper takes an attempt to introduce the extended sphere of problems of wheel and rail wear prediction, as well as the latest results reflecting the present state of the art.     

汽车驾驶人姿态监测系统研究综述（双语出版）

随着自动驾驶技术的发展,驾驶人将会参与更多的与驾驶无关的活动,从而呈现出新的姿态,这些新姿态是优化传统被动安全系统的重要切入点。而且在未来相当长的时间内,自动驾驶车辆的行驶依然依赖于人和系统的密切配合。对驾驶人姿态的观察,则可以为判断驾驶人是否有能力及时接管车辆提供帮助,从而确保安全、合理的人机交互过程。通过对大量相关文献的系统性梳理,综述了汽车驾驶人姿态监测技术的智能化发展趋势,从传感器种类以及相应的姿态监测算法出发,分析了目前不同监测系统的优缺点。研究发现,尽管传感器技术和姿态识别算法取得了明显进步,然而廉价稳定且能够在实际驾驶条件下对驾驶人姿态准确感知的监测系统依然缺乏。总体而言,目前的监测系统大多只是集中于对驾驶人局部身体部位的感知,缺乏实际驾驶条件下的性能分析,并且对驾驶人状态的实时感知和预测能力仍有待完善。最后,针对目前监测系统所面临的问题,对未来可能的研究方向进行展望,并提出主动式立体视觉系统和压力传感器阵列相融合的驾驶人姿态监测方式。研究成果将为驾驶人姿态监测系统的研究提供参考和借鉴,从而有助于道路交通安全水平的进一步提升,同时也可为人机交互界面的设计带来启发。