Roll angle estimator based on angular rate measurements for bicycles

ABSTRACT

Measuring the roll angle of single-track vehicles has always been a challenging task; however, accurate and reliable measurements of this magnitude are paramount for controlling the stability of these vehicles, both for autonomous riding and for safety reasons. A roll angle estimation is also useful in other situations, such as tests to perform the identification of the parameters of the rider control. In this work, a new algorithm is presented for estimating the roll angle of bicycles. This estimator, based on the well-known Kalman filter, employs a wheel speed sensor to approximate the speed of the vehicle, and three angular rate sensors, which are currently small and affordable sensors. The proposed method was implemented in a microcontroller and tested in a bicycle and the results were compared with measurements obtained with optical sensors, showing a good correlation. Although it has not been tested in motorcycles, comparable results are expected.     

Development of a new time domain-based algorithm for train detection and axle counting

This paper presents an innovative train detection algorithm, able to perform the train localisation and, at the same time, to estimate its speed, the crossing times on a fixed point of the track and the axle number. The proposed solution uses the same approach to evaluate all these quantities, starting from the knowledge of generic track inputs directly measured on the track (for example, the vertical forces on the sleepers, the rail deformation and the rail stress). More particularly, all the inputs are processed through cross-correlation operations to extract the required information in terms of speed, crossing time instants and axle counter. This approach has the advantage to be simple and less invasive than the standard ones (it requires less equipment) and represents a more reliable and robust solution against numerical noise because it exploits the whole shape of the input signal and not only the peak values. A suitable and accurate multibody model of railway vehicle and flexible track has also been developed by the authors to test the algorithm when experimental data are not available and in general, under any operating conditions (fundamental to verify the algorithm accuracy and robustness). The railway vehicle chosen as benchmark is the Manchester Wagon, modelled in the Adams VI-Rail environment. The physical model of the flexible track has been implemented in the Matlab and Comsol Multiphysics environments. A simulation campaign has been performed to verify the performance and the robustness of the proposed algorithm, and the results are quite promising. The research has been carried out in cooperation with Ansaldo STS and ECM Spa.     

VIV response of a flexible cylinder with varied coverage by buoyancy elements and helical strakes

Many significant engineering challenges have emerged as the petroleum industry has moved their field development and production activities into increasingly deeper water depths. The design of deepwater marine risers presents the combined challenges to minimize top tensioning requirements, mitigate any flow-induced vibrations, and if possible to increase the expected fatigue life of these slender structural members. As part of the design process to achieve these goals external buoyancy modules and strakes have been employed. To gain insight into the complex multi-mode response behavior a recent experimental study was performed and the analysis of selected data sets is presented. In the experiments a horizontal cylinder with a length to diameter ratio of 263 was fitted with a variety of strake and buoyancy element configurations. The models were towed at uniform speeds ranging from 0.4 to 2.0 m/s and fiber optic strain gages were used to measure both in-line and cross-flow strain response. The resulting time series information was processed utilizing the method of time domain decomposition formulated for strain data input and the introduction of modal assurance criterion to resolve the modal strain information that included frequency, mode shape, and critical damping ratio information. The pre-tensioned cylinder without appendages was used as a base case and the results were basically consistent with expectations. In the case of 0.8 m/s low-tension test, multiple closely spaced non-overlapping peaks were observed in both in-line and cross-flow directions and were identified as being of the same mode with mode shapes distorted away from purely sinusoidal behavior. The test data for the 100% coverage by helical stakes demonstrated the effectiveness of that suppression device over the range of current velocities investigated. The most interesting case was that of a staggered combination of helical strakes and buoyancy element whose total for each type of coverage was equal. This effective asymmetric VIV suppression approach is presented and discussed in detail.     

基于光纤光栅传感的铁路异物侵限监测系统研究

随着我国铁路建设进入快速发展时期,对铁路安全运输提出了更高的要求,建立铁路异物侵限监测系统显得很有必要。由此提出用光纤布喇格光栅应力传感器替代传统的电类传感器,分析了光纤布喇格光栅应力传感器的工作原理,设计了基于光纤光栅传感的铁路异物侵限监测系统并分析了预警过程。所设计的铁路异物侵限监测系统实现了分布式测量、光缆传输、系统集成、实时监测、在线控制等功能,为列车安全运行提供了可靠保障。     

基于光纤光栅传感技术的江阴大桥结构应变监测研究

江阴大桥自1999年通车以来,就一直经历着大交通和重载交通的双重考验.主桥钢箱梁受交通荷载的影响最为直接,极易因荷载的不断作用而产生疲劳损伤.对荷载影响反应最直接的就是主桥钢箱梁结构的内部应变,通过对结构应变的监测,可以较好地掌握桥梁受动态荷载作用下的结构响应.本文采用光纤光栅传感技术对钢箱梁结构的重点部位进行应变监测...     

光纤光栅传感测量中交叉敏感问题及解决方案

目前已有的基于光栅Bragg光栅的各种传感器,基本上都是直接或间接的利用应变和温度改变光纤的中心波长,以达到测试所需被测量的目的。但是中心波长不仅会随测试点的应变发生改变,还会随着环境温度的波动而发生变化,即存在温度和应变交叉敏感的问题。解决温度、应变交叉敏感问题即实现温度和应变的分离检测是光纤Bragg光栅应变传感器得到实际应用的重要前提[1]。文章从理论上分析了引起交叉敏感的物理机制,较为全面地介绍了几种主要的解决方案,并对其主要特点进行了简单的分析。     

插值法在瞬态转速计算中的应用研究

利用齿轮-磁电式传感器装置对TBD234V6型柴油机进行台架瞬时转速信号的测试,并针对采样频率不够高导致瞬时转速测试分辨率过低的问题,采用插值的方法,对用较低采样频率采集到的原始信号进行插值处理,以提高采样频率。结果表明:插值处理以后得到平滑的转速波形图,瞬时转速的波形得到了很好的恢复,此方法能够较好地反映柴油机转速的变化规律。     

非介入式气体管道泄漏检测的可行性研究

现有气体管道泄漏检测技术中,多采用打孔装表的感测方式,这不仅给被测量带来影响,还会造成新的安全隐患.针对上述问题,文中提出了一种非介入式的气体管道泄漏检测方法,采用压电声波传感器,粘贴在气体金属管道外壁,检测管道内部气体介质传播的低频泄漏声波信号.介绍了实验平台的搭建方法,并通过实验验证了这种方法的可行性.这种非介入式...     

隧道超前地质预报对传感器预埋位置确定的应用

结合高速公路科研实际情况,利用地质雷达对隧道围岩情况作出超前地质预报,精确判断围岩结构、状态、类别等,对预埋传感器位置和类型选择进行精确指导,实现合理科学的实时监测围岩位移、温度、应力等各种参数的变化。     

基于FBG传感器的船体结构实时监测系统

为实时监测船舶在高速航行时船体结构的状态,评估船体关键部位的强度,提高船舶的安全性.基于FBG传感技术,结合船体结构特征,采用信号处理和强度评估等理论,构建船体结构强度监测体系,以实现船体结构典型位置技术状态监测及预警判断.研究成果可为各种类型船舶的安全健康监测提供一定的借鉴和参考.