低压电力线载波点对点通信性能测试系统设计与研究

针对低压电力线载波点对点通信性能主要表现在发送信号电平、接收灵敏度、抗干扰能力和阻抗适应性等方面,文章建立了一套可定量测试上述参数的低压电力线载波点对点通信性能测试系统的技术方案,并阐述了系统测试原理和方法。测试系统结构简单,实用性强,能自动实现载波点对点通信信号频带和最大输出信号电平及频带外干扰电平测试、数据传输可靠性测试、接收灵敏度测试、通信抗干扰测试和模拟低压线路参数综合测试,从而为比较、改进和设计载波通信单元提供技术依据。     

基于nRF905的小型无线温度传感器设计

文章基于nRF905无线芯片,设计了一款无线温度传感器,该传感器工作在433 MHz免许可频段,点对点通信。测试结果表明该系统功耗低,可靠性高,通信距离较远。     

基于Cortex-M3与FPGA的无线生理参数监测仪的设计

设计了以Cortex-M3与FPGA为核心的无线生理参数监测仪,可以实时监测人体运动状态下的重要生理参数。文中介绍了监测仪的测量原理,和以心电信号提取为主的系统采集模块、无线电信号传输和中继器等硬件电路的设计;在该硬件系统中,采用NRF24L01无线芯片完成自定义协议数据通信,中继器则采用Cyclone III的FPGA实现对信号预处理及显示功能,同时控制Cy68013经USB与上位机通信;最后进行了对血氧饱和度的实时监测和系统性能的测试,验证了监测仪的可行性。     

自动测试系统通用信号调理平台构建

在以计算机为核心构成的测试系统中，采用一种新型总线构建了信号调理平台，该总线结构设计简单合理，包含了系统模块通信所必需的信号。并对系统的可靠性进行了分析和设计，使用该总线对各调理模块进行控制，建立的信号调理平台具有良好的通用性、扩展性、灵活性、稳定性和可靠性，并且可节省测试资源，能够满足多种测试系统的需要。     

基于无线传输技术的汽车智能仪表设计

针对传统仪表显示采用线束连接,导致汽车仪表系统的抗电磁干扰能力弱、准确率和精度等较低的问题,提出一种基于CAN无线总线技术的智能仪表系统。结合汽车仪表工作原理,根据智能仪表系统的功能需求,分别从硬件和软件方面对智能仪表系统进行设计;利用CAN无线通信技术实现汽车数据采集与不同电子器件的通信。最后,通过脉冲信号模拟对智能仪表系统进行测试,验证了该设计方案的可行性,为智能技术的应用提供参考。     

水润滑轴承水膜压力无线测试系统研究

为了深入研究水润滑轴承特性,需要了解轴承真实的水膜压力分布,而传统的滑动轴承润滑膜压力测试无法获得轴承全周水膜压力的连续分布,且采用集流环作为信号传输媒介,其成本较高、对输出信号干扰较大。针对以上不足,研究并设计了一种无线测试系统,可测量水润滑轴承全周水膜压力,并实时监测水润滑轴系的运转情况。介绍了测试系统组成,包括无线采集发射与接收装置、传感器与信号调理模块、测试软件及水润滑轴承试验台,最后应用此系统对八沟槽水润滑平面橡胶轴承的水膜压力进行测试,并与仿真结果对比分析。结果表明,该测试系统实用性良好,可用于测试其他材料和结构的水润滑轴承的水膜压力。     

基于SPI总线的无线传感器网络节点

在基于无线传感器网络的分布式测试系统中,为了使同一传感器节点能根据测试任务的需要方便地添加或删除某些功能模块,提出了一种星形结构的SPI总线的设计方案,用于节点的控制模块和各功能模块之间的通信.该方案在传统的SPI通信协议的基础之上,增加了从机呼叫信号以实现通信过程中的2次硬件握手,使节点能以分组交换的方式将测试数据打包发送回基站.实践检验证明:基于SPI总线设计的传感器节点工作稳定,功能拓展方便,可以完成复杂的测试任务.     

自动气象站信号模拟器通信系统的设计与实现

阐述了通信系统在自动气象站信号模拟器应用中的意义,针对信号模拟器的特点选择了适当的通信方式和通信协议,提出了硬件抗干扰措施,并介绍了以Delphi语言为基础的上位机通信模块设计。测试与实际应用结果表明,自动气象站信号模拟器和上位机之间可以可靠、稳定地实现通信。该通信系统在自动化控制系统和智能仪器仪表中具有良好的应用前景。     

旋转体动态数据采集系统的研制

本文成功研制了一种新颖、实用的旋转体动态数据采集系统－非接触式集流环。介绍了其工作原理。该集流环采用红外作为动、静装置之间信号传播媒介,对被测装置的转速没有限制,传输精度高。此外,该集流环对工作环境条件无严格要求,且安装方便。实测结果表明,该系统抗干扰能力强、测试精度高。     

基于远距离通信模块的无线传感器网络设计

针对规模化农田需要远距离无线传输的特点和对通信数据实时性强的要求,提出一种基于远距离通信模块、以太阳能电池和铅酸蓄电池为供电方式的无线传感器网路设计方案.经试验测试,该系统的传输距离大于4 km,频率波动小于0.25 MHz;与GPRS通信模块相比,该系统抗干扰能力强,实时性好,保证了无线传感器节点间远距离通信的成功率.     

Laser vibrometry measurements of an optically smooth rotating spindle

Laser doppler vibrometry (LDV) is a well-established non-contact method, commonly used for vibration measurements on static objects. However, the method has limitations when applied to rotating objects. The LDV signal will contain periodically repeated speckle noise and a mix of vibration velocity components.In this paper, the crosstalk between vibration velocity components in laser vibrometry measurements of a rotating dummy tool in a milling machine spindle is studied. The spindle is excited by an active magnetic bearing (AMB) and the response is measured by LDV in one direction and inductive displacement sensors in two orthogonal directions simultaneously. The work shows how the LDV crosstalk problem can be avoided if the measurement surface is optically smooth, hence the LDV technique can be used when measuring spindle dynamics.     

A comprehensive technique for measuring the three-dimensional positioning accuracy of a rotating object

A method for measuring the accuracy of rotating objects was studied. Rotating axis errors are significant; such as the spindle error of a machine tool which results in increased surface roughness of machined work pieces. Three capacitance-type displacement sensors were used to measure the position of a rotating master ball. The sensors were mounted at the three orthogonal points on the spindle axis. The measurement data were analysed for rotating spindle accuracy, not only for the average roundness error but also for the spindle volumetric positional error during rotation. This method is simple and economical for industrial field use for regular inspection of spindles using portable equipment. The time taken for measurement and analysis using this method is only about two hours. This method can also measure microscopic amplitudes in 3-D directions of vibrating objects.     

三维激光扫描仪的测量精度控制定量分析

数据测量是逆向工程中的一个重要阶段,测量数据的精度是决定着后续数字化模型能否在误差控制范围内还原为已有实物的关键。本文基于一种先进测量设备——ATOS三维光学测量系统,对该系统在测量过程中产生的误差来源进行了详尽的分析,总结了测量实物时误差产生的特点,提出了提高三维激光扫描仪测量精度的三种方法。结合某叶片模具活块,定量分析比较了三种方法改善测量精度的效果,指出坐标系的设定和坐标系堆叠的流程是控制测量精度的关键。     

光切法扫描测量策略及其数据合成

根据常见测量对象的几何特征及光切法三维轮廓测量特点，设计了两种测量系统结构方案，并重点介绍了四轴卧式系统四种扫描测量策略及其数据台成方法，最后给出了实物测量结果。     

Development of an automatic cumulative-lead error measurement system for ballscrew nuts

Ballscrew is a precision mechanical component used to convert rotational motion to linear motion in the precision linear stage. The precision measuring system for the screw's cumulative-lead error is already well known. Up to now, however, there is no suitable measuring equipment for internal cumulative-lead error of the nut. For a matching pair, it is not reasonable to understand the quality of only one piece. This paper presents a developed automatic cumulative-lead error measuring system for ballscrew nuts. The nut is clamped by a rotational stage, in which the moving angle is detected by a rotary encoder. The probing ball is inserted into the nut and remains in contact with the thread groove of the nut. The probe arm is mounted on a linear slide so that when rotating the nut, the probing ball will be pushed by the groove wall and moved axially. A high-resolution diffraction scale is employed to detect the linear movement of the probe to nanometer resolution. Combining the angular and linear motions, the cumulative-lead error of the nut can be realized. In practice, however, the nut will cause typical spindle errors during rotating, including axial slip, radial run out, and tilt motions. These errors have to be compensated in order to guarantee the accuracy of measurement results. A multi-sensor error compensation system is thus developed. Experimental results show the applicability of this developed measuring system.     

定桨距变转速风力机气动性能测试与流场测量

针对非并网风电系统,搭建了风力机性能测试平台,设计了流场测量系统。利用该平台和测试系统,通过改变磁粉制动器的励磁电流实现对风轮转速的高精度控制。通过测量分析发现了风轮后气流旋转方向与风轮旋转方向相反的规律,得到了输出功率越大,其尾迹内气流的轴向速度越小的结论。该实验结果为定桨距变转速风力机的转速控制策略制定提供了依据,也为非并网风电系统风力机的优化和设计提供了参考。     

全自动测量轴圆度的V形法测量系统研究

为了寻找一种结构简单、精度高、造价较低而且能全自动地测量轴圆度的方法,本文根据一般V形法的实际应用及测量精度,对一般的V形法测量系统进行了全自动化研究.本文介绍了V形法的测量原理、数据处理方法、全自动V形法测量系统的研究以及主要单元部件的构成.通过计算机控制、直流伺服电机带动被测轴旋转、计数码盘计算被测轴转过的角度、测微头自动拾取测量数据、计算机计算并输出计算结果,能够实现全自动测量轴的圆度,测量精度可达到十纳米级.     

Stereo vision for 3D measurement: accuracy analysis, calibration and industrial applications

This paper evaluates the accuracy of different camera calibration and measurement methods used in 3D stereo vision with CCD cameras. These methods are evaluated by means of several precision tests, determining their error limits under specified conditions of operation. To check the precision of such systems, a CMM and some calibration objects, such as grids, plates, spheres, etc. are used. Two practical applications are described: a cost-effective system for the measurement of free-form surfaces, able to generate CAD models and measuring programs for CMMs. The system aims to reduce some difficulties associated with stereo vision and to speed up the traditional digitizing process. The other application involves car frame measurement. A new automatic measuring system has been developed, allowing contactless car frame measurement through two rotating CCD cameras.     

GUlDELESS SPATIAL COORDINATE MEASUREMENT TECHNOLOGY BASED ON CODING POLE

A new method of guideless spatial coordinate measurement technology based on coding pole and vision measurement is proposed. Unequal spacing of bar code is adopted to pole, so that the code combination of pole image in measuring field is unique. Holographic characteristics of numeric coding pole are adopted to obtain pole pose and pole probe position by any section of bar code on the pole. Spatial coordinates of measuring points can be obtained by coordinate transform. The contradiction between high resolution and large visual field of image sensor is resolved, thereby providing a new concept for surface shape measurement of large objects with high precision. The measurement principles of the system are expounded and mathematic model is established. The measurement equation is evaluated by simulation experiments and the measurement precision is analyzed. Theoretical analysis and simulation experiments prove that this system is characterized by simple structure and wide measurement range. Therefore it can be used in the 3-dimentional coordinate measurement of large objects.     

高速旋转叶片振动实时监测系统研究

高速旋转叶片振动的非接触测量是叶片振动测量中极具发展前景的技术。研究了高速旋转叶片振动实时监测系统 ,叶端定时传感器、传感器脉冲信号采集电路和叶片振动信号的实时分析和处理。