Experimental analysis of the slip sinkage effect based on real vehicle test

To improve the semi-empirical model, the slip sinkage effect is analyzed based on the real vehicle test. A dynamic testing system is used to gain the dynamic responses of wheel-soil interactions, The Gauss-Newton algorithm is adopted to estimate the undetermined parameters involved in the slip sinkage models. Wong＇s original model is compared with three typical slip sinkage models on the prediction performance of a drawbar pull. The maximum error rate, root mean squared error and correlation coefficient are utilized to evaluate the performance. The results indicate that the slip sinkage models outperform Wong＇s model and greatly improve the prediction accuracy. Lyasko＇s model is confirmed as an outstanding one for its comprehensive performance. Hence, the existence of the slip sinkage effect is validated. Lyasko＇s model is selected as an optimal one for the practical evaluation of military vehicle trafficability.

基于Simulink Real-Time的汽车空调半实物仿真试验系统研发

针对多样化汽车空调电子零部件的高效、低成本总成级测试需求,研究基于一汽大众速腾1.6 L车型原型,设计了基于Simulink Real-Time的汽车空调半实物仿真试验系统。该系统集成了真实的汽车空调总成、制冷循环以及包含宿主机和目标机的双机实时仿真系统,用于开发和运行台架监控和空调控制模型,为汽车空调电子零部件提供半实物仿真测试环境。通过系统集成及功能验证,结果表明,汽车空调半实物仿真试验系统能够实现汽车空调基本控制功能,同时在不同工况下实现乘员舱温度控制的稳定性,稳态误差控制在±1℃以内。此外,该系统还具备灵活调整空调运行工况和状态的能力,为汽车空调电子零部件提供了高效、低成本的半实物仿真测试环境。

On modeling approach for embedded real-time software simulation testing

Modeling technology has been introduced into software testing field. However, how to carry through the testing modeling effectively is still a difficulty. Based on combination of simulation modeling technology and embedded real-time software testing method, the process of simulation testing modeling is studied first. And then, the supporting environment of simulation testing modeling is put forward. Furthermore, an approach of embedded real-time software simulation testing modeling including modeling of cross-linked equipments of system under testing （SUT）, test case, testing scheduling, and testing system service is brought forward. Finally, the formalized description and execution system of testing models are given, with which we can realize real-time, closed loop, mad automated system testing for embedded real-time software.

Real-time embedded software testing method based on extended finite state machine

The reliability of real-time embedded software directly determines the reliability of the whole real-time embedded sys- tem, and the effective software testing is an important way to ensure software quality and reliability. Based on the analysis of the characteristics of real-time embedded software, the formal method is introduced into the real-time embedded software testing field and the real-time extended finite state machine （RT-EFSM） model is studied firstly. Then, the time zone division method of real-time embedded system is presented and the definition and description methods of time-constrained transition equivalence class （timeCTEC） are presented. Furthermore, the approaches of the testing sequence and test case generation are put forward. Finally, the proposed method is applied to a typical avionics real- time embedded software testing practice and the examples of the timeCTEC, testing sequences and test cases are given. With the analysis of the testing result, the application verification shows that the proposed method can effectively describe the real-time embedded software state transition characteristics and real-time requirements and play the advantages of the formal methods in accuracy, effectiveness and the automation supporting. Combined with the testing platform, the real-time, closed loop and automated simulation testing for real-time embedded software can be realized effectively.

Delay-dependent stability and added damping of SDOF real-time dynamic hybrid testing

It is well-recognized that a transfer system response delay that reduces the test stability inevitably exists in real-time dynamic hybrid testing （RTDHT）. This paper focuses on the delay-dependent stability and added damping of SDOF systems in RTDHT. The exponential delay term is transferred into a rational fraction by the Pad6 approximation, and the delay-dependent stability conditions and instability mechanism of SDOF RTDHT systems are investigated by the root locus technique. First, the stability conditions are discussed separately for the cases of stiffness, mass, and damping experimental substructure. The use of root locus plots shows that the added damping effect and instability mechanism for mass are different from those for stiffness. For the stiffness experimental substructure case, the instability results from the inherent mode because of an obvious negative damping effect of the delay. For the mass case, the delay introduces an equivalent positive damping into the inherent mode, and instability occurs at an added high frequency mode. Then, the compound stability condition is investigated for a general case and the results show that the mass ratio may have both upper and lower limits to remain stable. Finally, a high-emulational virtual shaking table model is built to validate the stability conclusions.

An Automatic Testing System of Scheduling Strategies in Real-Time UNIX

This paper proposes a formal model of the automatic testing system for scheduling strategies in real-time UNIX and describes the algorithm of the key part of the system. The model of the system is an important technology of the automatization of software development. According to the model presented in the paper, many different kinds of automatic testing systems can be designed and developed easily. At the end of the paper, the prototype proves the feasibility of the model and design.

Simulation of large-scale numerical substructure in real-time dynamic hybrid testing

A solution scheme is proposed in this paper for an existing RTDHT system to simulate large-scale finite element （FE） numerical substructures. The analysis of the FE numerical substructure is split into response analysis and signal generation tasks, and executed in two different target computers in real-time. One target computer implements the response analysis task, wherein a large time-step is used to solve the FE substructure, and another target computer implements the signal generation task, wherein an interpolation program is used to generate control signals in a small time-step to meet the input demand of the controller. By using this strategy, the scale of the FE numerical substructure simulation may be increased significantly. The proposed scheme is initially verified by two FE numerical substructure models with 98 and 1240 degrees of freedom （DOFs）. Thereafter, RTDHTs of a single frame-foundation structure are implemented where the foundation, considered as the numerical substructure, is simulated by the FE model with 1240 DOFs. Good agreements between the results of the RTDHT and those from the FE analysis in ABAQUS are obtained.

Velocity plus displacement equivalent force control for real-time substructure testing

This paper employs a velocity plus displacement（V＋D）-based equivalent force control（EFC） method to solve the velocity/displacement difference equation in a real-time substructure test. This method uses type 2 feedback control loops to replace mathematical iteration to solve the nonlinear dynamic equation. A spectral radius analysis of the amplification matrix shows that the type 2 EFC-explicit, Newmark-β method has beneficial numerical characteristics for this method. Its stability limit of Ω = 2 remains unchanged regardless of the system damping because the velocity is achieved with very high accuracy during simulation. In contrast, the stability limits of the central difference method using direct velocity prediction and the EFC-average acceleration method with linear interpolation are shown to decrease with an increase in system damping. In fact, the EFC-average acceleration method is shown to change from unconditionally stable to conditionally stable. We also show that if an over-damped system with a damping ratio of 1.05 is considered, the stability limit is reduced to Ω =1.45. Finally, the results from an experiment with a single-degree-of-freedom structure installed with a magneto-rheological（MR） damper are presented. The results demonstrate that the proposed method is able to follow both displacement and velocity commands with moderate accuracy, resulting in improved test performance and accuracy for structures that are sensitive to both velocity and displacement inputs. Although the findings of the study are promising, additional test data and several further improvements will be required to draw general conclusions.

房地产行业冲击下的系统性风险

房地产是当前中国最大的“灰犀牛”之一.本文首次就房地产行业冲击对我国所有行业可能造成的系统性风险影响进行了压力测试.为克服以往二维压力测试无法刻画所有行业之间联动的问题,本文提出了一种新的动态高维Copula(DHDC)宏观压力测试方法.还提出了一种新的系统性风险度量—条件市值损失(CoMVL),它结合了已有风险度量CoES和MES的优点,又融入了市值信息,从而更好地测量负向冲击的影响.利用中国18个行业的指数回报数据,基于DHDC压力测试的实证分析表明:房地产行业冲击对其他各个行业产生了广泛的不利影响,如果未来一个月内房地产行业累积收益率下跌20%,将会导致制造业、金融业、信息技术业和采矿业的市值分别下跌10.14万亿元、0.81万亿元、0.65万亿元和0.42万亿元,收益率分别下跌29.10%、7.81%、15.27%和10.92%;房地产行业冲击对一个行业造成的市值损失75%以上归结于间接影响,即房地产行业通过影响其它行业而其它行业又对目标行业造成的影响.风险溢出网络分析表明,房地产行业冲击主要通过信息技术业、采矿业、批发零售业、交运仓储业、水电煤气业和建筑业六个行业对制造业和金融业产生了不利影响.拓展分析还表明,房地产行业冲击时间越长,对其他行业产生的不利影响也就越大;而且房地产行业负向冲击产生的影响要大于同等幅度下正向冲击产生的影响,即当前稳定房地产下跌预期对防范系统性风险相对更加重要.一系列稳健性检验都证实了本文结果的可靠性.本研究对于全面理解和防范房地产行业冲击对其它各行业可能带来的系统性风险具有重要的政策指引意义.

基于扫视路径速度的隧道入口驾驶舒适性分析

为了更准确地评价公路隧道入口段驾驶员的视觉舒适性,以隧道入口段的驾驶员视觉特性为研究对象,在云南上鹤高速公路的野鸭塘1号、2号和3号隧道开展实车试验,采集驾驶员的注视与扫视时间、视点位置、瞳孔直径等眼动参数,并依次对20名驾驶员进行问卷调查。基于试验数据和问卷调查结果,提出扫视路径速度指标并验证其合理性。结果表明:扫视路径速度能够有效地对隧道入口段的驾驶视觉舒适性进行评价;当隧道照明条件相同时,新型蓄能反光发光材料能够使驾驶员的平均扫视路径速度降低50.62%,峰值扫视路径速度降低40.32%。通过对视觉舒适指标的关联性分析,进一步表明:扫视路径速度与驾驶员的视觉舒适性呈反比关系;随着隧道入口光环境质量的提高,驾驶员的扫视时间占比增加,进而扫视所用时间变长,扫视路径速度减慢,此时驾驶员的视觉舒适性较高有利于安全行驶,反之则不利于行车安全。

深海环境腐蚀试验技术及研究进展

从深海实海环境试验、模拟试验、原位电化学测试、数值仿真等方面阐述了深海环境试验技术的发展演变过程。介绍了国内外主要深海腐蚀研究使用的试验装置种类,各类装置的优缺点和使用场景,并以试验装置为平台,发展了金属材料深海原位电化学测试技术及深海测试数据实时远程传输技术。介绍了实验室模拟深海环境腐蚀试验技术由单因素模拟到多因素模拟,并结合力学及实时测试的发展历程。阐述了数值仿真技术在深海环境腐蚀研究方面的应用,推介了2项ISO深海环境试验方法国际标准,回顾了近期在材料深海环境腐蚀研究方面取得的最新成果。面向深海装备应用的需求,从新试验技术发展出发,探讨了深海试验技术研究的发展方向和趋势。

实时数据库数据的批量写入及性能测试研究

通过对石油化工行业使用较多的PHD实时数据库在多模式下的数据批量写入,以标准差指标对测试值进行可信度分析、测试调校,得出多模式下实时数据批量修改、更新测试的最优结果,探索一种行之有效的工业实时数据库优化、应用的方法。

RNA实时荧光核酸恒温扩增检测技术在儿童支原体肺炎早期诊断及疗效判断中的价值

目的 考察实时荧光核酸恒温扩增检测技术(SAT)在儿童肺炎支原体肺炎(MPP)早期临床诊断中的价值及其在评价MPP转归以及判断药物疗效中的作用。方法 选取社区获得性肺炎(CAP)住院患儿451例,所有患儿在入院24 h内采集血清标本,采用被动凝集试验检测肺炎支原体(MP)特异性抗体[MP抗体检测(MP-Ab)],并采集咽拭子标本提取MP-RNA(MP-SAT法)。对MPP患儿在完成大环内酯类药物治疗第1疗程、完成大环内酯类药物治疗第3疗程时复查MP-Ab和MP-RNA。根据MPP诊断标准将其分为MPP组(n=183)和非MPP组(n=268)。比较MP-SAT和MP-Ab诊断MPP的准确性(敏感度、特异度、阳性预测值、阴性预测值)。对病程<7 d入院前未使用大环内酯类药物的MPP患儿进行动态观察,考察在大环内酯类药物(阿奇霉素)治疗MP不同时间点(入院时、完成第1疗程和完成第3疗程时)MP-SAT和MP-Ab的阳性率以及患儿临床和影像学表现(咳嗽、发热、肺部体征和CT表现)变化情况。结果 MP-SAT和MP-Ab诊断MPP的准确性比较差异无统计学意义(P>0.05);病程<7 d患儿组中MP-SAT诊断MPP的敏感度、特异度、阳性预测值、阴性预测值均优于MP-Ab(P<0.001或P<0.05或P<0.01)。病程<7 d入院前未使用大环内酯类药物治疗的MPP患儿共42例,该组患儿在入院时、完成阿奇霉素治疗第1疗程和完成阿奇霉素治疗第3疗程时,MP-SAT检测阳性率分别为88.09%(37/42)、88.09%(37/42)和9.52%(4/42);MP-Ab检测阳性率分别为26.19%(11/42)、100.00%(42/42)和100.00%(42/42),在不同时间点MP-SAT和MP-Ab阳性率比较差异有统计学意义(P<0.001,P<0.05,P<0.001)。该组患儿完成第3疗程时MP-SAT阳性率较入院时明显下降(P<0.001),临床症状(咳嗽、发热)、肺部体征及肺部CT表现较入院时明显好转(均P<0.001),MP-SAT结果与临床症状、肺部体征及肺部影像学表现变化趋势相一致。结论 SAT检测MP-RNA可作为儿童MPP的早期诊断依据,同时也可作为评价MPP转归及判断临床治疗效果的指标。

miRNA表达谱在产前诊断胎儿先天性心脏病中的研究

目的:探究微小RNA(microRNA,miRNA)表达谱在产前诊断胎儿先天性心脏病(congenital heart disease,CHD)中的应用。方法:收集2021年1月—2022年12月于天津市中心妇产科医院就诊的30例超声确诊为CHD的孕妇(病例组)和同期10例要求行羊水穿刺的孕妇(对照组),用Illumina测序平台对2组孕妇的羊水上清进行全转录组测序,2组孕妇的全部miRNA进行归一化,分析差异表达的miRNA。从差异表达的miRNA中挑选P<0.05和|log2 FC|>3(差异倍数,Fold Change,FC)的miRNA再在羊水和外周血中进行实时荧光定量聚合酶链反应(real time fluorescence quantitative polymerase chain reaction,RT-qPCR)验证,比较羊水中miRNA测序与RT-qPCR的差异倍数,挑选外周血与羊水表达调控方向一致的miRNA。结果:共发现138个差异表达miRNA,其中85个上调,53个下调。进一步挑选出了15个差异表达的miRNA,羊水中miRNA测序与RT-qPCR结果比较相一致。外周血与羊水中表达调控方向一致的miRNA有2个,分别为miR-222-3p和miR-189-5p,这2个miRNA在病例组母血中表达量较对照组显著上升(均P<0.05)。结论:母血中miRNA作为新的血清学标志物可以初步应用于筛查胎儿CHD。

亮度和速度协同下公路隧道口路段驾驶舒适度研究

为探究山区双车道公路隧道口路段驾驶心理负荷的变化特性,本文采用实车试验的研究手段,招募27名驾驶人作为被试,选择重庆市境内的9座隧道作为试验场景,采集驾驶人、车辆和驾驶环境的行车数据,使用驾驶人的心率增长率表征驾驶心理负荷。通过数据分析,对驾驶人在隧道口路段的驾驶心理负荷与亮度和速度的相关性进行研究。结果表明,山区双车道公路隧道入口段的驾驶心理负荷大于出口段;在环境亮度小于500 cd·m^(-2)时,驾驶心理负荷对亮度的变化更为敏感,进而提出亮度变化率的计算公式,当亮度变化率在60%时,黑洞和白洞效应对驾驶人的心理影响趋于相同;在隧道口路段,速度对驾驶心理负荷具有放大效应;根据驾驶心理负荷值,划分隧道口路段的驾驶舒适度区间,提出基于驾驶舒适度需求的亮度变化率和速度的安全阈值,并给出计及亮度变化率和隧道口净空高度的亮度曲线。

基于轮力感知装置的软地面通过性测试系统

针对车辆的地面通过性试验方法主要局限于模型试验而缺乏实车试验的现状,提出了一套基于轮力感知装置的软地面通过性测试系统。系统以维轮力感知装置为核心,辅以轮速传感器、视觉传感器、GPS等多种车载设备。试验结果表明本文所提出的测试系统能够在多种软地面条件下完成牵引力、滑移率等通过性关键性指标的实时测量,进而为通过性地图的建立提供有力支撑。

基于设计运行条件的实际道路测试场景复杂度计算模型

自动驾驶车辆在实际道路行驶的安全性与外部交通要素、驾驶员状态以及本车状态密切相关。自动驾驶面临的一大难题是实际交通环境具有道路形态、自然环境、交通参与者及事件等在时间和空间维度的随机性特征,测试场景复杂度存在的差异造成了自动驾驶测试过程的不可复现性和测试结果的不可对比性,导致自动驾驶评价缺乏统一量化的测试环境基准。本文提出了一种基于设计运行条件的实际道路测试场景复杂度计算模型,系统考虑了网联功能、驾驶员感知能力、本车执行能力对自动驾驶车辆在实际道路中面临相关场景时的复杂度影响,建立了以道路等级、交通设施、临时交通变化、交通参与者、自然环境、网联信息、驾驶员状态和本车状态等8个要素大类为基础的自动驾驶实际道路测试场景复杂度计算模型要素库,建立了基于设计运行条件和层次分析法的自动驾驶功能实际道路测试场景复杂度计算模型。采用基于智能化网联化的技术逻辑影响传递机制计算场景要素权重系数,并在实际道路测试中验证了本文方法的可行性和合理性。

新型平衡舵阴极保护设计与保护效果评价

目的 针对新型平衡舵结构的电偶腐蚀薄弱区域,设计并优化牺牲阳极保护系统,并对保护效果进行评价。方法 基于边界元法,开展新型平衡舵电偶腐蚀仿真研究,分析电偶腐蚀薄弱区域。针对腐蚀薄弱区域,采用经验法设计牺牲阳极保护系统,开展服役初期和服役3 a后阴极保护效果仿真。从涂层破损率和阳极数量对阴极保护效果的影响出发,优化阴极保护系统。开展物理模型试验,对优化后阴极保护系统的保护效果进行评价。结果 电偶腐蚀主要发生在壳体和底座等支撑材料处,必须采取严格的防腐措施。采用经验法设计的牺牲阳极保护系统在服役初期可以使平衡舵保护电位均负于–800m V,处于良好的阴极保护状态。随着阳极的消耗,服役3 a后,阴极保护系统无法为平衡舵提供有效保护。涂层破损率的增加和阳极数量的减少,都会使平衡舵阴极保护电位正移。通过物理模型试验验证了优化后阴极保护模型的可靠性,对比试验结果,模型的预测误差在5%以内。结论 优化后的阴极保护方案为涂层+8块牺牲阳极,可以在服役3 a涂层破损率达20%的严苛工况下,为平衡舵提供有效阴极保护。优化后的阴极保护系统,铝阳极用量减少30%,有助于节省船舶动力。

同心分注井在线电动验封仪研制及应用

随着油田开发的不断深入,分层注水仍是补充地层能量、实现油田稳产、提高采收率的主要开发方式,原有同心分层注水井验封技术存在仪器定位难、密封件易损坏、验封效率低等问题,采用设计和试验相结合的研究方法,研制了同心分注井在线电动验封仪,并配套测调、验封一体多功能地面控制系统,集成流量、上/下压力等多参数测试技术,实现了一次下井、多层验封测试。试验表明,验封仪的坐卡/解卡性能、胶筒坐封/解封性能、整机承压能力、密封承压能力均能达到要求,现场应用效果良好,有效解决了验封效率不高等问题,提高了分层注水测试效率和合格率,为提升油田精细注水效果提供了可靠的工艺技术。

一种实艇试验测控系统

为提高海上试验测试技术水平,设计一种实艇试验测控系统。采用计算机作为主控平台,以实艇推进器为研究对象,利用传感器完成对压力、扭矩等参数的采集,通过计算机屏幕显示并将数据储存在硬盘中。试验结果表明:该装置可实现对试验数据的采集与储存,为实现实艇海上试验提供条件支持,为无人艇的研究提供参考。