基于模型的CBTC区域控制系统安全软件开发

传统的软件开发方法不能满足基于通信的列车控制(CBTC)区域控制系统(ZC)的开发需求.结合北京地铁亦庄线研究项目,介绍一种基于模型的系统开发方法,给出ZC系统的软件容错结构,阐述该系统的移动授权和列车管理功能建模方法,并从模型覆盖率分析和形式化验证两方面深入分析系统安全性保障措施.ZC系统的研究项目表明,基于模型的开...     

考虑ATP限速的ATO控制算法研究

一般列车自动运行(ATO)控制算法不直接考虑列车自动防护系统(ATP)限速的约束,因此可能造成列车在正常运行情况下的紧急停车。本文提出一种基于模型预测控制MPC(Model Predictive Control)的ATO控制算法,在控制器设计中直接考虑ATP限速约束,能够保证在ATO控制列车正常运行情况下不会触发ATP紧急制动,从而提高列车运行效率和舒适度。仿真结果表明该方法是有效的。     

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.     

A Novel Method for Character Segmentation in Natural Scenes

Introduction Nowadays the applications of scene text recog-nition are rapidly expanding with the developmentof portable digital imaging devices[1]. However,character extraction from scene images has alwaysbeen a challenging problem due to complex back-ground, uneven illumination, shadows and noise ofimages[2]. Besides, languages also impose anotherlevel of variation in text. Characters in such lan-guages as Chinese, Japanese and Korean are usual-ly composed of several strokes, which do not n…     

Model predictive driving simulator motion cueing algorithm with actuator-based constraints

The simulator motion cueing problem has been considered extensively in the literature; approaches based on linear filtering and optimal control have been presented and shown to perform reasonably well. More recently, model predictive control (MPC) has been considered as a variant of the optimal control approach; MPC is perhaps an obvious candidate for motion cueing due to its ability to deal with constraints, in this case the platform workspace boundary. This paper presents an MPC-based cueing algorithm that, unlike other algorithms, uses the actuator positions and velocities as the constraints. The result is a cueing algorithm that can make better use of the platform workspace whilst ensuring that its bounds are never exceeded. The algorithm is shown to perform well against the classical cueing algorithm and an algorithm previously proposed by the authors, both in simulation and in tests with human drivers.     

Slip-based terrain estimation with a skid-steer vehicle

In this paper, a novel approach for online terrain characterisation is presented using a skid-steer vehicle. In the context of this research, terrain characterisation refers to the estimation of physical parameters that affects the terrain ability to support vehicular motion. These parameters are inferred from the modelling of the kinematic and dynamic behaviour of a skid-steer vehicle that reveals the underlying relationships governing the vehicle-terrain interaction. The concept of slip track is introduced as a measure of the slippage experienced by the vehicle during turning motion. The proposed terrain estimation system includes common onboard sensors, that is, wheel encoders, electrical current sensors and yaw rate gyroscope. Using these components, the system can characterise terrain online during normal vehicle operations. Experimental results obtained from different surfaces are presented to validate the system in the field showing its effectiveness and potential benefits to implement adaptive driving assistance systems or to automatically update the parameters of onboard control and planning algorithms.     

城市快速路网络交通路由诱导方法设计与案例分析

为了达到均衡城市快速路网交通负荷,提高交通运行效率的目的,该文介绍了一种模型预测路由控制方法。其控制任务被描述为一个动态的、离散时间、空间的、带有约束控制变量的最优控制问题,通过在未来较长的时段内求解每一个控制周期的最优问题来实现反馈控制。案例分析结果表明,模型预测路由控制方法能够考虑时变的交通状态,取得良好的控制效果,可为先进的交通管理系统规划设计提供依据。     

Analytical Solution for Model-Based Dynamic Power Factor Measurement in AC Resistance Spot Welding

On the basis of welding transformer circuit model, a new measuring method was proposed. This method measures the peak angle of the welding current, and then calculates the dynamic power factor in each half-wave. An artificial neural network is trained and used to generate simulation data for the analytical solution, i.e. a high-order binary polynomial, which can be easily adopted to calculate the power factor online. The tailored sensing and computing system ensures that the method possesses a real-time computational capacity and satisfying accuracy. A DSP-based resistance spot welding monitoring system was developed to perform ANN computation. The experimental results suggest that this measuring method is feasible.     

预应力混凝土桥梁徐变模型试验相似关系研究

讨论预应力混凝土桥梁徐变模型试验主要影响因素及处理原则,提出了模型梁设计时需满足的相似关系;基于CEB-FIP(MC90)徐变模型,建立了模型梁与原型梁跨中徐变长期上拱的相似关系.模型梁试验推算值与实桥测试值比较表明,推算值具有较好的精度.本文为预应力混凝土桥梁非足尺结构模型的徐变试验研究提供新思路,建立的公式在工程试验研究中具实用性.     

Tyre pressure monitoring using a dynamical model-based estimator

In the last few years, various control systems have been investigated in the automotive field with the aim of increasing the level of safety and stability, avoid roll-over, and customise handling characteristics. One critical issue connected with their integration is the lack of state and parameter information. As an example, vehicle handling depends to a large extent on tyre inflation pressure. When inflation pressure drops, handling and comfort performance generally deteriorate. In addition, it results in an increase in fuel consumption and in a decrease in lifetime. Therefore, it is important to keep tyres within the normal inflation pressure range. This paper introduces a model-based approach to estimate online tyre inflation pressure. First, basic vertical dynamic modelling of the vehicle is discussed. Then, a parameter estimation framework for dynamic analysis is presented. Several important vehicle parameters including tyre inflation pressure can be estimated using the estimated states. This method aims to work during normal driving using information from standard sensors only. On the one hand, the driver is informed about the inflation pressure and he is warned for sudden changes. On the other hand, accurate estimation of the vehicle states is available as possible input to onboard control systems.