Modeling and System Identification of the muFly Micro Helicopter

An accurate mathematical model is indispensable for simulation and control of a micro helicopter. The nonlinear model in this work is based on the rigid body motion where all external forces and moments as well as the dynamics of the different hardware elements are discussed and derived in detail. The important model parameters are estimated, measured or identified in an identification process. While most parameters are identified from test bench measurements, the remaining ones are identified on subsystems using the linear prediction error method on real flight data. The good results allow to use the systems for the attitude and altitude controller design.     

基于时延的微通信元主机原型性能测试

介绍服务元网络体系结构（SUNA）和基于非层次网络体系结构的微通信元系统架构（MCES）。针对MCES主机原型进行有效测试,以进一步验证SUNA的可行性和有效性。讨论基于时延的MCES主机原型性能测试方法和过程。测试结果表明SUNA和MCES是可行的。     

微型直升机自主飞行辅助视觉系统研究

为了实现微型直升机自主飞行,论文设计了实时的计算机视觉系统。该系统包括机载上的硬件设备和软件算法,能够实现目标识别、特征点提取和位置估计。文中设计了特定图标,并主要依据颜色来进行快速识别。此外,通过检测4个共面的图像特征点,能够在单目单帧的基础上计算出直升机相对于特定目标的三维位置信息。视觉系统任务由位于机载上的IntelSitsang板来执行。由于受到板子运算能力的限制,每秒钟可以处理5帧160×120的彩色图像。飞行实验结果表明,该视觉系统的目标识别率高达93%,角点计算偏差小于3个像素,同时自身定位的三维位置坐标平均偏差为8cm、13cm和6cm。因此,该视觉系统通过精确自身定位,能够很好的辅助微型直升机完成自主悬停、起飞和降落等飞行任务。     

直升机发动机超转信号发生器的设计

本文介绍了基于DDS技术的直升机超转信号发生器,同时介绍了DDS工作原理,设计了信号放大器和隔离功率输出级。此信号发生器输出信号频率误差小、分辨率高。     

Geometric Bone Modeling: From Macro to Micro Structures

There is major interest within the bio-engineering community in developing accurate and non-invasive means for visualizing, modeling and analyzing bone micro-structures. Bones are composed of hierarchical bio-composite materials characterized by complex multi-scale structural geometry. The process of reconstructing a volumetric bone model is usually based upon CT/MRI scanned images. Meshes generated by current commercial CAD systems cannot be used for further modeling or analysis. Moreover, recently develop...     

直升机驾驶仪的故障诊断与自动测试系统

本文介绍了某直升机自动驾驶仪的性能检测、故障诊断及其自动测试(ATE)系统,利用基于VXI总线的软硬件集成环境,进行了故障和可测试性定义,开发了自动检测和故障诊断程序,可以定位到SRU级子部件和模拟放大器板级关键元件,具有较强的故障诊断定位能力和诊断效率。     

直升机桨叶动平衡试验技术研究

通过研究直升机桨叶动平衡试验技术,重点分析了采用基准桨叶校准试验台、标准桨叶和伴随桨叶,以及采用标准桨叶和伴随桨叶校验批生产桨叶的几个关键步骤和技术途径,统一了部分术语和定义,整理了相关参数的计算公式,是对直升机桨叶动平衡试验技术的一次消化和总结,对于深入研究基准桨叶校准方法具有非常重要的意义,同时也为开展新型号直升机的桨叶动平衡试验打下了基础.     

Image-Based Visual PID Control of a Micro Helicopter Using a Stationary Camera

This paper proposes an image-based visual servo control method for a micro helicopter. The helicopter does not have any sensors to measure its position or posture on the body. A stationary camera is placed on the ground and it obtains image features of the helicopter. The differences between current features and given reference features are computed. PID controllers then make control input voltages for helicopter control and they drive the helicopter. The proposed controller can avoid some major difficulties in computer vision such as numerical instability due to image noise or model uncertainties, since the reference is defined in the image frames. An experimental result demonstrates that the proposed controller can keep the helicopter in a stable hover.     

直升机自动驾驶仪测试系统软件的设计与实现

针对直升机自动驾驶仪装机前的性能检测,设计了直升机自动驾驶仪测试系统软件。详细叙述了自动驾驶仪测试系统软件的设计方案,重点分析了RS-485总线冲突的解决方案,基于Modbus协议数据包的解读机制,测试软件实时性的保证。实时测试软件采用模块化设计思想,实现了测试的自动化和综合化,实际应用表明,该测试软件操作简便,运行稳定可靠。     

通用基础软件等级保护测评原型的研究

文章提出了一种针对国产通用基础软件的等级保护测评原型。该原型在深入对比分析国内外主要等级保护相关标准的基础上,充分考虑了国产通用基础软件自身的特点。原型的内容既涵盖了软件代码、体系结构风险等常规软件安全测试项目,还包括了身份鉴别、访问控制、完整性等等级保护中的要求。本文提出的测评原型既可以为建立国产通用基础软件的安全测试标准体系提供参考,也可以用来指导国产通用基础软件的安全性测试工作。     

平台上的无人直升机非线性预测姿态控制

针对在平台上的无人直升机姿态控制,设计了1个非线性预测姿态控制器,该预测控制器具有解析解不需要在线优化,通过查表的方式可以方便地得到满足设计要求的控制器参数。讨论了当输入饱和时的处理方法,通过仿真比较了当输入出现饱和时剪切法和方向保持法对系统性能的影响。最后,将非线性预测控制器和PID控制器的进行了比较,仿真结果说明采用该控制器系统响应比PID控制快,并且可以去除通道耦合引起的过大的超调量。     

直升机尾桨叶疲劳试验技术的研究

基于直升机尾桨叶疲劳试验技术研究的现状,对尾桨叶疲劳试验实现技术进行了重点阐述.根据尾桨叶疲劳试验的加载及测量要求,结合尾桨叶构型特性,设计制造了可同时对尾桨叶施加离心力、挥舞力、摆振力、扭力及法兰盘压载荷的尾桨叶疲劳试验台,并说明了尾桨叶疲劳试验台的工作原理.通过应用对尾桨叶粘贴应变片的方法测得了 3件尾桨叶疲劳试验...     

From Family First to the FBI: Children, ideology and Cyberspace

The Internet and child protection are usually discussed as if one inevitably follows the other. This article questions the process by which children are constructed on the Internet and suggests that the ideological agenda of the organisations that advocate the protection of children must be questioned. In particular, it is argued that many of these organisations proceed from a view of the child that is based on a conservative view of family relationships that is not obviously in children's best interests. The problem is that these views of the child have begun to permeate the state apparatus, which itself polices the Internet leading to an orthodoxy that is difficult to challenge.     

腕戴式集成电气测量测试系统原型设计

以PSoC5 LP为硬件开发平台,以PSoC Creator为软件开发平台,构建集成示波、频谱分析、信号(波形)发生以及信息交互功能的系统.显示外设采用Memory LCD,频谱分析通过快速傅里叶变换(FFT)实现,根据真任意波形发生技术(Ture arb)实现信号发生,扩展CC2541蓝牙模块实现与移动终端的信息交互.系统原型集成采用有限状态机实现多种功能,并用物理按键进行操作和切换.初步完成了集成有4种功能的腕戴式电气测量测试系统,达到了设计要求.     

微型磁通门的优化分析与性能测试

对铁芯结构的改进有利于满足微型磁通门传感器降低功耗的要求,但不同的拓扑结构所取得的效果不同,为此对铁芯结构进行了优化分析,并采用MEMS工艺制备了不同铁芯结构的微型磁通门进行性能测试与对比验证.测试结果表明,优化后的多孔铁芯结构能更好的降低微型磁通门传感器的功耗与噪声,提高灵敏度,改善器件的整体性能.     

一种直升机配电盒线路逻辑测试设备的设计与实现

为降低X系列直升机多型左/右配电盒线路通电测试所带来的测试风险，将其线路逻辑测试分为不加电情况下的线路导通测试与加电情况下的线路通电测试两类，两者均包括交流主通路、直流主通路和其他控制线路三类测试。为满足X系列直升机多种左/右配电盒整机线路逻辑测试需求，采用自动测试理论进行测试设备的研制。利用各种程控部件(包括数字万用表、电压源/电流源等)和自研的适配器箱、接触器箱搭建测试设备硬件平台，并基于VC++ 6.0开发相应的测试软件。最后针对X系列某型直升机左/右配电盒，对测试设备功能进行测试验证，测试结果表明其有效性。所做研究对其他系列直升机配电盒的整机线路逻辑测试具有借鉴意义。     

微型磁通门性能指标的综合测试与分析

对铁芯结构的改进有利于提高微型磁通门传感器的性能,采用MEMS工艺制备了多孔铁芯结构微型磁通门,并对所制备的微型磁通门进行主要的工作参数和性能指标的综合测试,分析了激励电流和激励频率对灵敏度、线性范围、噪声、剩磁误差等性能指标的影响规律.对实验结果的分析结论为传感器选择合适工作参数提供了数据支持.     

From First Conception to First Demonstration: the Nascent Years of Machine Translation, 1947–1954. A Chronology

The early history of applying electronic computers to the task of translating natural languages is chronicled, from the first suggestions by Warren Weaver in March 1947 to the first demonstration of a working, if limited, program in January 1954.     

Empirical investigation towards the effectiveness of Test First programming

The Test First (TF) programming, which is based on an iterative process of “setting up test cases, implementing the functionality, and having all test cases passed”, has been put forward for decades, however knowledge of the evidence of the Test First programming’s success is limited. This paper describes a controlled experiment that investigated the distinctions between the effectiveness of Test First and that of Test Last (TL) (the traditional approach). The experimental results showed that Test First teams spent a larger percentage of time on testing. The achievable minimum external quality of delivered software applications increased with the percentage of time spent on testing regardless of the testing strategy (TF or TL) applied, although there does not exist a linear correlation between them. With four years’ data, it is also found that a strong linear correlation between the amount of effort spent on testing and coding in Test First teams, while this phenomenon was not observed in Test Last teams.