基于ZigBee的便携式矿用多参数传感器设计

基于ZigBee无线通信技术,结合现有的煤矿传感器,设计了一款便携式矿用安全监测传感器。该传感器具有自组网、小体积、高效率、低功耗、低成本的特点,集信号采集、液晶显示和组网通信功能于一体。该传感器集成监测瓦斯浓度、温度、电流、压力等多种环境参数,有效弥补了矿用单参数传感器功能单一的不足;以无线通信代替有线通信,可固定安装或由工作人员随身携带,覆盖更多的监测盲点,更有利于系统的扩展和维护。     

船载测控雷达偏馈信号动态控制系统的设计

为了满足船载统一测控系统沟通无线偏馈射频链路进行遥测误码率测试的要求,进一步构建系统联调联试的动态射频信号环境,设计了船载测控雷达偏馈信号动态控制系统。通过系统监控台手动或自动远程控制位于天线背部中心体的数控衰减器,可实现雷达天线在对冷空的情况下接收偏馈射频信号幅度的变化,也可实现船载测控雷达系统联调过程中模拟目标动态变化情况,进而分析对系统跟踪性能的影响。该系统经过数次海上测控任务的检验,证明其方法科学有效、操作方便快捷、运行稳定可靠,达到了充分检验设备性能、提高任务准备效率的目的。     

Experimental investigation of noise suppression using the modified up-and-down method

The noise suppression efficiency is experimentally investigated for discrete stroboscopic signal transformation providing 5–15 μV (RMS) sensitivity. A balanced comparator based on tunnel diodes is used as a clocked comparator. Ordinary and modified up-and-down methods are used to measure the instantaneous signal values. The experimental results are compared to the theoretical calculations.     

基于正交频分复用的自适应载波调控策略

针对现今众多无线宽带传输方案采用OFDM技术的现状,在分析FLASH-OFDM及其改进技术Flexband的基础上,提出了多频蜂窝网的自适应载波调控策略。在单个蜂窝中采用了3个载波,其覆盖范围分为远、中、近三个等级;用户根据自适应载波调控策略选择信号质量好的信道。仿真结果表明,该方案能够获得更高的网络吞吐率及频谱利用率,并能支持更多的用户,提高了系统容量。     

饮用水溴离子浓度测量装置数据采集系统设计

针对一种基于微波感应的新型饮用水中溴离子浓度测量装置中微弱电压信号采集和分析的需求,设计了一种采集系统,包括信号采集部分和上位机显示部分。信号采集部分对传感器输出的微弱信号的放大和滤波后由C8051F310单片机自带的A/D转换器采集并通过串口发送给LabVIEW编写的上位机,上位机进行数据的接收、分析并显示溴酸盐浓度值。实验表明：该采集系统稳定可靠,可以作为饮用水溴离子浓度测量装置的数据采集系统。     

一种带有限位功能的步进电机控制器

为了适应调焦系统中爬山算法的搜索复位和区域限定要求,对通用步进电机控制器进行了改进,使其可以利用位置感应电路的限位信号主动完成搜索复位和限位.步进电机控制器通过了功能仿真,并在可编程门阵列器件中进行了实验.结果表明该控制器实现了预期的功能要求,复位与限位功能正常.     

An active approach for detection of incipient faults

The methodology of auxiliary signal design for robust fault detection based on a multi-model (MM) formulation of normal and faulty systems is used to study the problem of incipient fault detection. The fault is modelled as a drift in a system parameter, and an auxiliary signal is to be designed to enhance the detection of variations in this parameter. It is shown that it is possible to consider the model of the system with a drifted parameter as a second model and use the MM framework for designing the auxiliary signal by considering the limiting case as the parameter variation goes to zero. The result can be applied very effectively to many early detection problems where small parameter variations should be detected. Two different approaches for computing the test signal are given and compared on several computational examples.     

三维直角坐标系下三环网络的超L型瓦仿真

传统的超L型瓦仿真算法主要采用穷举的方法,效率较低,且有一定的局限性。针对上述问题,将三维直角坐标系引入三环网络,在三维直角坐标系下,提出广义三环网络G(N;s1,s2,s3)的超L型瓦仿真算法,利用C++和OpenGL实现超L型仿真,并求得其相关参数l、m、n,以及三环网络的直径D。实验结果表明,该算法具有较高的执行效率和更强的通用性。     

空气弹簧隔振台特性试验及信号处理算法研究

超精密测量对环境振动要求非常严格,其仪器设备中多安装隔振装置。为评估某重点实验室圆度仪中使用的仪用小型空气弹簧隔振台的隔振性能,利用压电式加速度传感器设计振动测试试验。根据振动测试中信号的实际情况,设计信号处理算法,对采集到的加速度信号进行预处理、积分运算、频谱分析,消除信号中低频趋势项和干扰噪声,还原实际振动状况,准确获取隔振系统振动位移曲线及其固有频率。试验表明,该空气弹簧隔振系统各项指标满足隔振要求。信号处理算法对振动测试中的加速度信号处理具有一定指导意义,也可作为故障诊断中加速度信号处理的参考。     

A new index of serial-link manipulator performance combining dynamic manipulability and manipulating force ellipsoids

The inertia matching ellipsoid (IME) is proposed as a new index of dynamic performance for serial-link robotic manipulators. The IME integrates the existing dynamic manipulability and manipulating-force ellipsoids to achieve an accurate measure of the dynamic torque-force transmission efficiency between the joint torque and the force applied to a load held by an end-effector. The dynamic manipulability and manipulating-force ellipsoids can both be derived from the IME as limiting forms, with respect to the weight of the load. The effectiveness of the IME is demonstrated numerically through the selection of an optimal leg posture for jumping robots and optimal active stiffness control, and experimentally through application to a pick-up task using a commercial manipulator. The index is also extended theoretically to the case of a manipulator mounted on a free-flying satellite.     

Synchronous and asynchronous handling of abnormal events in the μsystem

This paper presents a general model for dealing with abnormal events during program execution and describes how this model is implemented in the μSystem. (The μSystem is a library of C definitions that provide light-weight concurrency on uniprocessor and multiprocessor computers running the UNIX operating system.) Two different techniques can be used to deal with an abnormal event: an exception, which results in an exceptional change in control flow from the point of the abnormal event; and an intervention, which is a routine call from the point of the abnormal event that performs some corrective action. Users can define named exceptions and interventions in conjunction with ones defined by the μSystem. Exception handlers and intervention routines for dealing with abnormal events can be defined/installed at any point in a program. An exception or intervention can then be raised or called, passing data about the abnormal event and returning results for interventions. Interventions can also be activated in other tasks, like a UNIX signal. Such asynchronous interventions may interrupt a task's execution and invoke the specified intervention routine. Asynchronous interventions are found to be useful to get another task's attention when it is not listening through the synchronous communication mechanism.     

基于PSD的水利工程变形监测系统设计及室内检验

为高精度实现水利工程变形测量,设计一套基于PSD的变形监测系统。将激光器安装在水利工程易出现变形的位置上,通过实时观察照射在PSD表面的光斑位置变化,测出水利工程水平和竖直方向的微位移。对PSD输出的信号进行处理,利用单片机对转换后的4路信号进行位置计算,并用遗传算法与LM-BP神经网络法相结合的模型对PSD进行非线性校正,将位置结果显示在数码管和系统界面上。监测系统在模拟水利工程环境的室内已检验设计功能,同时PSD作为新型传感器,分辨力高,信号处理简单,可代替其他监测设备广泛用于水利工程的变形监测。     

Interfacing digitiezed Disa anemometer output to an Apple II computer

For measuring the velocities in a fluctuating fluid flow, the new Disa 56C00 multichannel constant-temperature anemometer system can be used with the 56N00 signal analysis equipment to provide a digital output of mean, root mean square or correlation values. A simple interface arrangement and appropriate software control for reading data directly into an Apple II computer are described. With these the subsequent calculation of derived parameters, such as displacement and momentum thickness of boundary layers and turbulence intensity, can be quickly and easily completed.     

基于Halbach原理的电磁超声换能器永磁铁设计

在实际应用中,电磁超声换能器（electromagnetic acoustic transducer,EMAT）的转换效率低是一个普遍存在的问题,如何提高其检测效率是研究的重点。为了提高接收信号的幅度,对比了两种永久磁铁结构,选定了一种基于Halbach阵列的永磁铁的新型结构模型。对磁铁的提离距离做了仿真分析与实验研究,得出最合适的提离距离为2mm。通过理论计算与有限元方法的大量仿真与结构优化,验证了其结构的可行性与有效性。结果表明,新型EMAT结构能够有效提高接收信号的幅度,信噪比大约是传统EMAT结构的1.9倍。     

Capturing asymmetrical spectral regrowth in RF systems using a multislice behavioral model and enhanced envelop transient analysis

Nonlinear distortion in RF and microwave systems results in spectral regrowth of digitally modulated signals. The distortion above and below the main channel can be at different levels and this is attributed to baseband effects. This article presents a new multislice behavioral‐model architecture that captures this asymmetry and can be implemented in a variety of circuit simulators, including SPICE, harmonic balance (HB), envelope transient (ET), and system simulators. The work is experimentally validated using an HBT power amplifier at 2.5 GHz driven by a WCDMA signal. The model is used with envelope transient circuit simulation which is enhanced to accommodate an arbitrary baseband transfer function. © 2006 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2006.     

无人机地面在线检测软件的设计

依据无人机系统的组成和工作原理,针对系统的检测环节,设计了在线检测与监视软件.该软件使用Microsoft Visual C++6.0编写,可直接安装在地面指挥控制站,具有通用性;全系统加电后,进行飞行前、飞行中和异常模式的检测,制定故障等级,通过文字和语音方式进行告警提示.经过系统联试,表明该软件在无人机系统的可行性和优越性.     

Model-based temperature control of a diesel oxidation catalyst

The problem studied in this article is the control of a DOC (diesel oxidation catalyst) as used in aftertreatment systems of diesel vehicles. This system is inherently a distributed parameter system due to its elongated geometry where a gas stream is in contact with a spatially distributed catalyst. A first contribution is a model for the DOC system. It is obtained by successive simplifications justified either experimentally (from observations, estimates of orders of magnitude) or by an analysis of governing equations (through asymptotic developments and changes of variables). This model can reproduce the complex temperature response of DOC output to changes in input variables. In particular, the effects of gas velocity variations, inlet temperature and inlet hydrocarbons are well represented. A second contribution is a combination of algorithms (feedback, feedforward, and synchronization) designed to control the thermal phenomena in the DOC. Both contributions have been tested and validated experimentally. In conclusion, the outcomes are evaluated: using the approach presented in this article, it is possible to control, in conditions representative of vehicle driving conditions, the outlet temperature of the DOC within ±15 °C.     

火炮发射高过载信号存储测试系统设计

针对某高过载弹体无损回收试验系统,研制了一套火炮发射高过载存储测试装置.该装置以STM32为控制核心,实现信号调理、数据存储、串口通信等功能.软件设计上采用一次外触发+多次内触发的方式,有效规避了测试时误触发的现象.该装置将加速度传感器与存储测试电路分离安装,方便传感器的拆卸,可安装于发射弹体的尾部,能够检测并记录弹体发射过程中的加速度数据.试验后回收装置,利用上位机读取检测到的数据并显示波形,可以为之后弹体无损回收的理论分析、参数设置提供重要的实验依据.     

采煤机无线监测系统的设计

为准确获取采煤机的运行状态参数,提出了一种采煤机无线监测系统的设计方案。该系统在采煤机机身的指定部位安装具有特定功能的无线传感器节点,用于采集采煤机的工作信号,该信号由DSP处理后,通过无线MESH网络传至无线网桥AP,再通过光纤传送到中心计算机,中心计算机上的分析软件对接收到的采煤机的工作信号进行分析,并根据预先设定的门限值进行报警或其它处理。现场试验结果表明,该系统运行良好,无线MESH网络的信号强度能够满足采煤机无线监测系统的要求。     

一种数字式栏栅型频谱分析仪器设计

为设计一种基于μClinux&FPGA的数字频谱分析仪,采用Altera-EP2C35F484C8N,嵌入32位NiosII软核CPU,安装μClinux操作系统;首先对信号进行100MHz高速采样,通过软件汉宁窗加窗与库利-图基FFT运算,实现信号的频谱分析,然后将信号的频谱、相谱信息在640*480的TFT上以离散的栏栅式的图形显示;实验中系统工作稳定可靠,满足设计要求,实验表明该设计方法是行之有效的。