测试系统的组成

Architectures for Implementing a Hardware-in-the-Loop SystemOverviewYou can test embedded control systems more efficiently with the powerful method of hardware-in-the-loop (HIL) simulation. Safety, availability, or cost considerations can make it impractical to perform all the necessary tests with the complete embedded control system. Using HIL simulation, you can simulate the parts of the system that pose these challenges. By thoroughly testing the embedded control device in a virtual environment before proceeding to real-world tests of the complete system, you can maintain reliability and time-to-market requirements in a cost-effective manner even as the systems you are testing become more complex.ContentsComponents of an HIL Test System (2)Hardware Fault Insertion (2)Testing Multi-ECU Systems (2)Additional Processing Power—Distributed Processing (3)Simplified Wiring—Distributed I/O (4)Implementing HIL Test Systems (4)Next Steps (5)Components of an HIL Test SystemAn HIL test system consists of three primary components: a real-time processor, I/O interfaces, and an operator interface. The real-time processor is the core of the HIL test system. It provides deterministic execution of most of the HIL test system components such as hardware I/O communication, data logging, stimulus generation, and model execution. A real-time system is typically necessary to provide an accurate simulation of the parts of the system that are not physically present as part of the test.The I/O interfaces are analog, digital, and bus signals that interact with the unit under test. You can use them to produce stimulus signals, acquire data for logging and analysis, and provide the sensor/actuator interactions between the electronic control unit (ECU) being tested and the virtual environment being simulated by the model. The operator interface communicates with the real-time processor to provide test commands and visualization. Often, this component also provides configuration management, test automation, analysis, and reporting tasks.Figure 1. An HIL test system consists of three primary components: an operator interface, a real-timeprocessor, and I/O interfaces.Hardware Fault InsertionMany HIL test systems use hardware fault insertion to create signal faults between the ECU and the rest of the system to test, characterize, or validate the behavior of the device under these conditions. To accomplish this, you can insert fault insertion units (FIUs) between the I/O interfaces and the ECU to allow the HIL test system to switch the interface signals between normal operation and fault conditions such as a short-to-ground or open circuit.Figure 2. You can use hardware fault insertion to test the behavior of the ECU during signal faults. Testing Multi-ECU SystemsSome embedded control systems, such as an automobile, aircraft, or wind farm, use multiple ECUs that are often networked together to function cohesively. Although each of these ECUs may initially be testedindependently, a system’s integration HIL test sys tem, such as a full vehicle simulator or iron bird simulator, is often used to provide more complete virtual testing. When testing a multi-ECU control system (and even some single ECU control systems), two needs often arise: additional processing power and simplified wiring.Figure 3. Automobiles, aircraft, and wind farms use multiple ECUs. Additional Processing Power—Distributed ProcessingEven with the latest multicore processing power, some systems require more processing power than what is available in a single chassis. To address this challenge, you can use distributed processing techniques to meet the performance requirements of these systems. In very high-channel-count systems, the need is more than simply additional processing power, additional I/O is also necessary. In contrast, systems using large, processor-hungry models often use additional chassis only for the extra processing power, allowing those processors to remain dedicated to a single task for greater efficiency. Depending on how the simulator tasks are distributed, it may be necessary to provide shared trigger and timing signals between the chassis as well as deterministic data mirroring to allow them to operate cohesively.Figure 4. When using multiple chassis for additional processing power, it is often necessary to provide timing and data synchronization interfaces between them.Simplified Wiring—Distributed I/OImplementing and maintaining wiring for high-channel-count systems can pose costly and time-consuming challenges. These systems can require hundreds to thousands of signals be connected between the ECU and the HIL test system, often spanning many meters to compensate for space requirements.Fortunately, deterministic distributed I/O technologies can help you tame these wiring complexities and provide modular connectivity to ECUs, which allows for efficient system configuration modifications. Instead of routing all connections back to a single rack containing one or more real-time processing chassis instrumented with I/O interfaces, you can use deterministic distributed I/O to provide modular I/O interfaces located in close proximity to each ECU without sacrificing the high-speed determinism necessary for accurate simulation of the virtual parts of the system.This approach greatly reduces HIL test system wiring cost and complexity by making it possible for the connections between the ECU and the I/O interfaces to be made locally (spanning less than a meter) while a single bus cable is used to span the additional distance to the real-time processing chassis. Additionally, with the modular nature of this approach, HIL test systems can easily scale, incrementally, from a multi-ECU test system in which all but one of the ECUs are simulated to a complete system integration HIL test system where none of the ECUs are simulated.Figure 5. Deterministic distributed I/O interfaces greatly reduce HIL test system wiring cost and complexity because the connections between the ECU and the I/O interfaces can be made locally. Implementing HIL Test SystemsAfter you have selected the appropriate architecture for your HIL test system, the first step in creating a HIL test system is to select the components that best meet your development requirements. NI provides a wide variety of real-time processing and I/O options for implementing HIL test systems. Because they are all based on open industry standards, you can be assured that they always deliver the latest advances in PC technology to your HIL test system and always meet future test system requirements.The NI HIL platform is open and extensible, which means that it can adapt to changing system requirements. Because of its modular architecture, the NI HIL platform can be easily upgraded with additional functionality, which helps you future proof your test systems and meet the requirements of the most demanding embedded software testing applications. In addition to the widest range of I/O on market, NI offers software tools that help you automate your HIL tests, perform post-processing and report generation, and map test results to requirements. These tools help you perform a wider range of tests earlier in the software development process, which reduces overall development cost while improving product quality.。

一、微波测试系统的认识和调试实验目的：1 了解微波测试系统的测量原理2 了解微波信号源的工作特性3 熟悉选频放大器的使用方法4 熟悉各种波导元件的功能和特征4 掌握测量线的使用方法5 掌握校准晶体检波器特性的方法6 学会频率测量和功率测量实验原理：一、微波测试系统微波测试系统通常由3部分组成:1等效信号源部分：包括微波信号源,功率,频率监视单元,隔离器.；2测量电路部分：包括测量线,调配元件,待测元件,辅助元件；3指示检测部分：指显示测量信号特性的仪表,如直流电流表,,测量放大器,功率计,示波器,数字频率计等。

如图所示：等效源 测量电路二、微波信号源通常微波信号源有电真空和固态的两种。

电真空的震荡器主要有反射速调管和磁控管等，而固态震荡器随着微波半导体技术的迅速发展，类型越来越多，如微波晶体管震荡器，体效应管震荡器，雪崩二极管震荡器等（1）反射速调管是一种微波电子管，利用速度调制方法（用高频电场控制电子运动）改变在交变电磁场中电子流的运动速度，从而将直流能量转化为微波能量。

它的震荡频率能在一定范围内改变，且容易调谐，并能做脉冲和频率调制。

反射式速调管分为内腔式和外腔式两类。

（2）磁控管震荡器主要是指多腔磁控管，由阳极、阴极和能量输出系统组成。

利用电场和磁场来控制电子运动来实现速度调制，从本质上可以说是一个置于磁场中的二极管。

它是现今产生强功率震荡的最常用的一种电子管。

(3) 固态震荡器，在振荡原理上，微波固态震荡器可分为两种基本类型：负阻型振荡器和反馈型振荡器。

微波晶体管振荡器大多属反馈型，而其他种类的微波固态震荡器多属负阻型。

其中体效应管就是负阻效应来产生微波振荡的，它是利用某些半导体材料的体效应——即转移电子机构来进行震荡的，因此，也称为转移电子二极管。

目前，制造体效应管的半导体材料多用n型砷化镓。

砷化镓的禁带宽度E g=1.43eV大于能谷间的距离ΔE，因此，当加大电场时，并不产生电子雪崩式的击穿（即电子被加速到足够大的能量时，能产生碰撞电离，使电子数目雪崩式倍增而击穿），而下能谷的电子很容易转移到上能谷去，随着外加电场的增大，从下能谷转移到上能谷去的电子数目也增加。

测试系统的构成测试系统的构成是由不同的组成部分组成的，这些组成部分主要包括测试策略、测试计划、测试用例、测试执行、缺陷跟踪和测试报告等。

这篇文章将会讨论这些组成部分以及它们在测试系统中的作用。

测试策略测试策略是测试系统中最重要的组成部分之一，它是测试的基础，规定了测试方法的方向和目标。

测试策略包括以下内容：测试目标测试目标是测试策略的关键部分，它明确了测试项目要达到的主要目标。

测试目标应明确、清晰、可测量和可跟踪。

测试范围测试范围包括了测试系统中需要进行测试的所有范围，它通常由需求文档、设计文档和功能规格说明书等决定。

测试方法测试方法是根据测试目标和测试范围确定的一种测试方式，它包括了测试用例设计、测试环境选择、测试工具选择等。

测试时间和资源测试时间和资源是测试策略中最容易被忽视的部分，它包括了测试所需要的时间、人力资源、设备、测试环境和测试工具等。

测试计划测试计划是测试的一个重要组成部分，它提供了测试活动的详细计划，包括以下内容：测试计划的目的和概述测试计划的目的和概述是为了让测试计划的所有参与者都了解测试计划的目标、排期、过程和范围。

测试计划的组成部分测试计划的组成部分包括测试计划的范围、测试进度、测试资源、质量标准和风险分析等。

测试计划的执行测试计划的执行包括测试活动的过程和结果，需要对测试活动进行监控和评估。

测试用例测试用例是测试系统中最核心的部分之一，它是测试数据、测试操作流程、测试结果和测试预期结果的集合。

测试用例需要满足完整性、正确性、可重复性和可自动化等需求。

测试执行测试执行是测试系统的直接实施环节，需要按照测试计划和测试用例进行系统测试和回归测试，确定软件产品的质量。

缺陷跟踪缺陷跟踪是测试系统中的一个指标，需要对测试执行中发现的缺陷进行精细化管理，包括缺陷的数据收集、分类、跟踪、管理和报告等。

测试报告测试报告是测试系统中的最终产物，它对测试执行和测试结果进行和分析，向测试负责人和项目管理团队提供详细的测试数据和统计信息，帮助项目进一步优化质量。

工程测试技术第一章1、测试系统组成及主要性能指标。

测量系统由荷载系统、测量系统、信号处理系统、显示与记录系统组成；测试系统的主要性能指标有精确度、稳定性、测量范围(量程)、分辨率和传递特性等。

2、测试系统的传递特性传递特性是表示测量系统输入与输出对应关系的性能，包括静态传递特性和动态传递特性。

3、简述测试系统选择的原则。

(1)灵敏度：灵敏度高，微小变化，测量范围窄，稳定性差；（2）准确度：测量结果与真值的一致程度，同等准确度，前高后低；（3）响应特性：不失真，延迟愈短愈好，输出紧跟输入变化；（4）线性范围线性范围内工作，保证测量准确度；（5）稳定性：输出随时间不变，漂移和零漂；（6）测量方式：接触与非接触、机械与电测，在线与非在线；（7）各特性参数之间的配合（匹配性）4、精度：测试系统给出的指示值和被测量的真值的接近程度；蠕变：固体材料在保持应力不变的条件下，应变随时间延长而增加的现象；回程误差：指在相同测试条件下和全量程范围A 内，在输入由小增大和由大减小的行程中，对于同一输入值所得到的两个输出值之间的最大差值h max 与A 的比值的百分率，即第二章1、传感器：能够将外界的非电信号，按一定规律转换成电信号输出的器件或装置。

2、电阻式传感器工作原理根据电阻应变效应先将被测量转换成应变，再将应变量转换成电阻3、钢弦式传感器的原理及应用由钢弦内应力的变化转变为钢弦振动频率的变化；应用：1）刚弦式混凝土表面应变计；2）钢弦式沉降仪；3）土压力计；4）混凝土应力；5）荷载盒（测力计）；6）锚索测力计、钢筋计；7）刚弦式位移传感器4、压电效应：有些电介质晶体材料在沿一定方向受到压力或拉力作用时发生极化，并导致介质两端表面出现符号相反的束缚电荷，其电荷密度与外力成比例，若外力消失时，它们又会回到不带电状态，这种由外力作用而激起晶体表面荷电的现象为压电效应。

5、压磁效应：铁磁材料受机械力作用，内部产生机械效应力，从而引起导磁系数发生变化。

1. 现代机械产品和信息化有何关系？机械产品的灵魂是测试系统，测试系统需要信息化的支持，信息化的两个特点是：一、网络化：协同手段、资源共享协同设计和制造、远程设计与制造、并行设计和制造。

二、数字化：信息化的核心。

在制造领域，它表现在：数字工厂、数字制造、数字装备等，同时，它又能大大提高设备的精确度。

2. 测试系统由哪些环节组成？测试系统包括传感器、信号调理、数据采集、数据处理、显示。

3. 周期信号谱和非周期信号谱有何异同？相同点：都是通过对时域信号进行傅里叶变换得到的，其幅值谱和相位谱的物理意义是一样的。

都是在无限的频带上作傅里叶展开。

不同点：周期信号非周期信号周期T T→∞圆频率ω0＝2Л/T ω0 →dω△ω无穷小谱线k.ω0 k.ω0 →ω连续4. 信号量化存在哪些误差？如何减少幅值误差？（1）幅值误差、失真、能量泄露。

（2）1.增大量化时分度的区间个数2.使区间取值接近信号的峰值3.增加A/D的采样位数。

5. 频谱混叠的原因是什么？如何实施抗混叠滤波？（1）折叠频率小于最高分析频率的采集而产生混频，欠采样产生频谱混叠（2）采集前滤去大于fd的，频率——抗混叠滤波，低通滤波频率为0—fd6. 何谓FFT？它主要解决什么问题？（1）FFT，即快速傅氏变换，是离散傅氏变换的快速算法，它是根据离散傅氏变换的奇、偶、虚、实等特性，对离散傅立叶变换的算法进行改进获得的。

（2）离散傅里叶变换（DFT）由于计算量太大，利用一般的计算机计算时需要耗费大量时间，满足不了一般系统的实时性要求。

FFT主要解决的问题是利用快速的算法来实现对信号的傅里叶变换，大大减少了傅里叶变换的计算量。

7. 什么是不失真测试？要满足什么条件？输入输出在时间轴上的的宽度相等，对应高度成比例，只是滞后一个位置t0，或者输入信号的个频率分量通过装置，均应被放大相同的倍数A08. 测试系统主要的静、动态参数包括哪些？静态参数：灵敏度、测量范围、精度、线性度等。