实时多任务控制软件可靠性设计及测试

对发动机电控系统实时软件进行了可靠性设计和测试。按事件触发类型和时间触发类型设计了实时多任务软件,对实时控制软件进行了抗干扰设计、失效恢复设计等可靠性设计;对控制软件进行了长时间的软件在环仿真测试以及硬件在环(HIL)仿真测试,验证了实时软件可靠性设计的有效性并检验了所设计软件的可靠性。通过对实时软件的仿真测试,减小了验证软件可靠性所需的实际发动机台架试验的工作量。     

预应力混凝土简支空心板梁桥静载校验系数分析

以内蒙古呼伦贝尔市境内的上护林大桥为工程背景,在预应力混凝土空心板桥的常规静载试验的基础上,提出断面应变校验系数的概念。结合常规校验系数与断面应变校验系数对该桥的工作状况进行评估,得出该桥横向联系及整体工作状况良好,且断面应变校验系数法可以在类似结构桥梁的荷载试验结果分析中加以推广和应用。     

自平衡试桩法荷载箱埋设位置探讨

自平衡试桩法是检测单桩竖向抗压极限承载力的一种试验方法.荷载箱的埋设位置是检测成功与否的重要因素之一.结合工程实例,就采用自平衡试桩法确定荷载箱埋设位置的问题进行探讨和总结,供同行参考.     

不同交联度环氧沥青混合料低温弯曲性能研究

环氧沥青作为一种交联的粘弹性材料,其低温力学性能受交联密度影响较大。该文介绍了其低温弯曲性能试验研究。采用交联度75.3%、71.4%、67.3%和58.4%的环氧沥青混合料,进行-20℃、-10℃、0℃、10℃温度下小梁三点弯曲性能试验。结果表明,不同交联度的环氧沥青混合料弯曲强度与模量随着温度的提高而降低,破坏变形与应变能密度随着温度的提高而增大。不同交联度的环氧沥青混合料弯曲强度、模量、破坏变形及应变能密度与温度关系基本一致,各弯曲性能参数的温度敏感区间也基本相同,交联度75.3%混合料的弯曲性能参数温度敏感区间为大于10℃,交联度71.4%和67.3%的温度敏感区间为0~10℃,交联度58.4%温度敏感区间为-10~0℃;温度敏感区间弯曲性能参数变化幅度较大,低于温度敏感区间,则弯曲性能参数变化幅度较小。环氧沥青混合料低温弯曲性能参数与温度、交联度之间具有较好相关性,可以建立混合料弯曲强度、模量、破坏变形及应变能密度与温度、交联度的关系,并用于混合料低温弯曲性能预测。     

装备远程测试保障技术研究

大型装备投资大、功能复杂且往往难以替代,要求运行保障的高可靠性、维护技能的多学科性和维护决策的科学性。为及时准确掌握装备的运行状况,利用多方专家资源进行装备技术保障,应当建设装备远程测试系统。文中分析了装备现场测试系统的设计,总结了装备远程测试技术的两种实现途径,包括面向装备的远程测试系统和面向诊断中心的远程测试系统,分别讨论了其适用范围。     

Fuel economy testing of autonomous vehicles

Environmental pollution and energy use in the light-duty transportation sector are currently regulated through fuel economy and emissions standards, which typically assess quantity of pollutants emitted and volume of fuel used per distance driven. In the United States, fuel economy testing consists of a vehicle on a treadmill, while a trained driver follows a fixed drive cycle. By design, the current standardized fuel economy testing system neglects differences in how individuals drive their vehicles on the road. As autonomous vehicle (AV) technology is introduced, more aspects of driving are shifted into functions of decisions made by the vehicle, rather than the human driver. Yet the current fuel economy testing procedure does not have a mechanism to evaluate the impacts of AV technology on fuel economy ratings, and subsequent regulations such as Corporate Average Fuel Economy targets. This paper develops a method to incorporate the impacts of AV technology within the bounds of current fuel economy test, and simulates a range of automated following drive cycles to estimate changes in fuel economy. The results show that AV following algorithms designed without considering efficiency can degrade fuel economy by up to 3%, while efficiency-focused control strategies may equal or slightly exceed the existing EPA fuel economy test results, by up to 10%. This suggests the need for a new near-term approach in fuel economy testing to account for connected and autonomous vehicles. As AV technology improves and adoption increases in the future, a further reimagining of drive cycles and testing is required.     

Map-induced journey-planning biases for a simple network: A Docklands Light Railway study

A usability study was conducted to identify the most effective prototype Docklands Light Railway map for installation on trains. This comprised a series of tasks that required station finding and also planning of routes between pairs of stations, with response time and accuracy as measures of performance. In addition, subjective ratings of map design were collected via questionnaire-based evaluations, and also ranked preferences between designs. A clear best-option was easily identifiable as a result of this research. The existing design was associated with the most journey planning errors, and two of the prototypes were associated with inefficient journey choices. The latter finding suggested that respondents were using unsophisticated planning strategies that were put at a disadvantage by certain route depictions. This has wider implications for suggestions that schematic maps should maintain topographical relationships in order to facilitate appropriate journey choices, with the danger that the inevitable increased complexity of line trajectories for such designs would simultaneously reduce the ability of passengers to identify the most appropriate routes.     

Vehicular emissions prediction with CART-BMARS hybrid models

Vehicular emission models play a key role in the development of reliable air quality modeling systems. To minimize uncertainties associated with these models, it is essential to match the high-resolution requirements of emission models with up-to-date information. However, these models are usually based on average trip speed, not on environmental parameters like ambient temperature, and vehicle’s motion characteristics, such as speed, acceleration, load and power. This contributes to the degradation of its predictive performance. In this paper, we propose to use the non-parametric Classification and Regression Trees (CART), the Boosting Multivariate Adaptive Regression Splines (BMARS) algorithm and a combination of them in hybrid models to improve the accuracy of vehicular emission prediction using on-board measurements and the chassis dynamometer testing. The experimental comparison between the proposed CART-BMARS hybrid model with the BMARS and artificial neural networks (ANNs) algorithms demonstrates its effectiveness and efficiency in estimating vehicular emissions.     

基于Lab VIEW汽车发电机测试系统设计与实现

介绍汽车发电机参数自动检测系统的结构、设计和实现技术，并对LabVIEW软件平台的设计原理、思想及其路线进行论述。通过虚拟仪器技术，力图降低汽车发电机检测系统开发成本，使其更加普及实用。结果表明，该系统能够为教学提供平台，并能够解决发电机检测不普遍的问题，能提供简洁友好的人机交互界面来进行参数的测量，易于维护和系统扩展等。     

电力机车辅助电源传动试验台系统控制策略研究

介绍了电力机车辅助电源传动试验台系统,对系统组成和工作原理进行了说明。其采用PWM整流器作为系统负载,利用PWM整流器调节被试逆变器的输出电流来进行各种工况的试验,PWM整流器采用了基于交流电压定向的电流控制策略实现解耦控制,并采用了预测电压法提高控制性能。