A study on an object transport system using ultrasonic wave excitation

The development of information and telecommunication industries leads to the development of semiconductor and optical industries. In recent years, the demand of optical components is growing due to the demand of faster network. On the other hand, conventional transport systems are not adequate for transporting precision optical components and semiconductors. Because the conveyor belt can damage precision optical components with contact force and a magnetic system would destroy the inner structure of semiconductor with magnetic field, a new system for transporting optical components and semiconductors is required. One of the alternatives to the existing systems is a transport system using ultrasonic wave excitation since it can transport precision components such as semiconductors and optical components without damage. In this paper, a transport system using 2-mode ultrasonic wave excitation was developed for transporting optical components and semiconductor, and its performance was evaluated. The relationship between transporting characteristics and flexural beam shapes were evaluated.     

High-accuracy ultrasonic temperature measurement based on MLS-modulated continuous wave

Ultrasonic temperature measurement has the potential to improve measurement accuracy by increasing the length of a received signal due to its excellent performance with noise resistance. However, when the distance between the transmitter and receiver is limited, the received signal can be polluted by strong multiple echoes, which can significantly degrade temperature accuracy. This paper proposes a method for high-resolution ultrasonic temperature measurement. With the use of a maximum length sequence (MLS)-modulated continuous wave, the obstructive effect of echoes is effectively suppressed. A hybrid method is employed for accurate time-of-flight (TOF) estimation by incorporating both cross-correlation and phase shift (PS), which is the basis of highly accurate temperature measurement. The experimental results in distilled water show that the proposed method estimates TOF with a standard deviation of less than 0.3 ns, and temperature errors consistently remain within ±0.04 °C.     

A novel method for construction of a point coordinate measuring instrument using ultrasonic waves

Point coordinate measuring instruments are applied in the geometric measurement of parts. In this instrument, ultrasonic waves are used for measuring distances using a method similar to the time-of-flight method. For improvement of the measurement resolution, an accurate value of the speed of sound is enhanced by using a phase-locked loop (PLL) circuit to generate a reference signal; this signal is dependent on the variation of the speed of sound. To measure the coordinate of a point, an ultrasonic signal is produced with a wireless transmitter on the surface of a part. The waves are received by a set of three ultrasonic receivers located at the corner of the room. By counting the pulses of that signal within a transmit-to-receive period, the distance between each pair of transducers can be determined. By increasing the coefficient of the frequency divider in the PLL, the output frequency increases and the resolution improves.     

小型飞行时间质谱装置的构建

飞行时间质谱仪（TOF MS）在准确度、分辨率、灵敏度、质量上限、分析速度等方面具有优势,在生命科学等领域发挥着重要作用。目前商用飞行时间质谱仪已经比较成熟,但仪器尺寸普遍较大,且价格昂贵,维护困难;而小型仪器则面临分辨率较低等问题。提高小型飞行时间质谱仪的分辨率,降低购置成本和维护成本,对于飞行时间质谱仪的大范围推广有着重要意义。本工作构建了一套分辨率较高的小型飞行时间质谱装置,包括真空系统、离子源、锥孔、引出加速及偏转模块、离子反射镜模块、探测器模块、电路系统等。该仪器主体尺寸较小（0.5 m×0.5 m×0.7 m）,飞行管长度仅0.25 m。由于采用了模块化设计思路,各个模块之间独立封装,仪器的维护、升级工作简单易行。该仪器的关键模块采用创新设计,使得在m/z 2 000处分辨率可达4 200。     

智能移动机器人超声波测距定位系统的研究

移动机器人技术是机器人研究领域的一个重要分支。为了赋予机器人智能控制和自主导航的能力,解决机器人开发过程存在着成本高、功耗大等问题,研究设计了一套基于超声波传感器的智能移动机器人测距定位系统,同时使机器人具有报警、避障及定位等功能。     

Image enhancement of simplified ultrasonic CT using frequency analysis method

In this paper, a simplified ultrasonic CT system, which uses the information in three directions, that is, 90°, +45° and —45° about the inspection plane, is applied to the high strength steel, and the frequency analysis method for enhancing the C scan or CT image is developed. This frequency analysis method is based on the frequency response property of the material. By comparing the magnitudes in the frequency domain, the special frequency which shows a significant difference between the welded joint and base material was found and used to obtain a C scan or CT image. Experimental results for several kinds of specimens, having a welded joint by electron beam welding, a weld joint by arc welding, on a fatigue crack, showed that the obtained C scan or CT image has better resolution than the results of previous experiments using the maximum value of the received waveform.     

超声检测机械手控制系统的设计

为实现超声检测的自动化,研制了一种关节机械手控制系统.该机械手由传感检测系统、伺服系统、总线智能节点和PC机等组成,借助单片机、数字控制、现场总线、计算机、机器人等技术,利用CAN现场总线进行通讯,通过控制实现自动控制并实时获取坐标信息,有利于缺陷的定位分析,其结构简单,性能价格比高,可应用于其他场合,具有广泛的适应性.     

用于低质荷比离子传输的射频四极杆导向装置的研制

离子传输系统是质谱仪的重要组成部分,主要作用是将离子高效率地传输到质量分析器。本工作研制了一种用于质子转移反应飞行时间质谱（PTR-TOF MS）系统的射频四极杆离子导向装置,四极杆长80 mm,杆半径2.6 mm,内切圆半径2.25 mm,该装置可针对性地实现低质荷比挥发性有机化合物（VOCs）离子的聚焦传输。利用SIMION 8.1离子光学模拟平台对装置的运行环境进行仿真,然后在自行搭建的测试平台上对装置的工作条件,如气压、频率和电压幅值进行测试。结果表明,仿真和测试结果具有较好的一致性,装置的工作气压范围较宽,在0.2~0.3 Pa时的传输效率最高;当频率为3~4 MHz,电压幅值（V_p-p）为500 V左右时,对丙酮、甲苯等低质荷比VOCs（相似文献   

高灵敏VOCs在线真空紫外单光子电离飞行时间质谱仪的研制

研制了一种高灵敏度在线膜进样真空紫外电离源飞行时间质谱仪（MI-SPI-TOF MS）用于检测低浓度挥发性有机物（VOCs）。仪器包括真空系统、膜进样接口、真空紫外单光子电离源、垂直加速反射式飞行时间质量分析器和数据采集系统等。该仪器使用聚二甲基硅氧烷（PDMS）膜作为大气压下直接进样的接口,膜的选择透过性能直接、快速地富集大气中VOCs,可实现快速在线进样检测。真空紫外单光子灯作为电离源,能将电离能低于10.6 eV的VOCs电离,形成分子离子峰。结果表明,该仪器的分辨率优于750 FWHM,对苯、甲苯、二甲苯和氯苯的检测限达10^-12 mol/mol级别,检测速度达秒级,可用于低浓度VOCs的实时在线检测。     

Optimized design for time-of-flight total neutron scattering instrumentation using Monte Carlo simulations with application for the characterization of disordered macromolecules

Abstract

A time-of-flight neutron total scattering instrument for the China Spallation Neutron Source (CSNS) was designed. The instrument is designed for disordered macromolecular systems with characteristic lengths below 10?nm. The coupled hydrogen moderator of CSNS was selected to ensure the favorable statistics at the smallest scattering vector of 0.01?Å^?1. The optics and geometry of the instrument were optimized to cover a wide range of scattering vectors from 0.01 to 70?Å^?1. The performance of the instrument was examined using a series of Monte Carlo simulations, which demonstrate that the flux on the sample, the resolution, and the range of the scattering vectors are comparable to those of other advanced neutron total instruments. Finally, a virtual experiment was performed with silica powder. The resulting scattering pattern is consistent with both the numeric calculation and the estimated resolution of the instrument. The designed total scattering instrument at CSNS allows the simultaneous observation of both atomic and nanometer scale structures, having the potential to become a powerful tool for studying the structure of disordered materials in the fields of polymers, biology, and condensed matter physics.     

Study of a risk-based piping inspection guideline system

A risk-based inspection system and a piping inspection guideline model were developed in this study. The research procedure consists of two parts--the building of a risk-based inspection model for piping and the construction of a risk-based piping inspection guideline model. Field visits at the plant were conducted to develop the risk-based inspection and strategic analysis system. A knowledge-based model had been built in accordance with international standards and local government regulations, and the rational unified process was applied for reducing the discrepancy in the development of the models. The models had been designed to analyze damage factors, damage models, and potential damage positions of piping in the petrochemical plants. The purpose of this study was to provide inspection-related personnel with the optimal planning tools for piping inspections, hence, to enable effective predictions of potential piping risks and to enhance the better degree of safety in plant operations that the petrochemical industries can be expected to achieve. A risk analysis was conducted on the piping system of a petrochemical plant. The outcome indicated that most of the risks resulted from a small number of pipelines.     

一种实用的红外成像系统图像仿真方法

为了实现对红外成像系统静态性能计算机仿真评估,提出一种用于静态红外成像系统图像的生成方法。红外成像系统的调制传递函数（MTF）和噪声是系统图像的主要影响源,针对这一点,对系统调制传递函数和各类噪声源分别进行分析和建模,再根据红外目标和背景的辐射特性建立红外标准图像。通过模型的建立最终得到红外仿真图像,结果表明该方法具有很好的应用前景。     

嵌入式结构光投射系统设计

结构光投射系统的设计搭建是结构光三维形貌测量系统成功实现的关键之一.传统的激光投射系统存在结构复杂、生成的结构光的质量较低等缺点;而常用的光学投影系统又存在不完全可控等缺陷,难以适应嵌入式的应用.设计搭建了基于自主设计的嵌入式实时数字微镜(DMD)模块的结构光投射系统,驱动电路自主设计,底层接口完全可控,实现了结构光投...     

Outdoor position estimation based on a combination system of GPS-INS by using UPF

This paper proposes a technique that global positioning system(GPS)combines inertial navigation system(INS)by using unscented particle filter(UPF)to estimate the exact outdoor position.This system can make up for the weak point on position estimation by the merits of GPS and INS.In general,extended Kalman filter(EKF)has been widely used in order to combine GPS with INS.However,UPF can get the position more accurately and correctly than EKF when it is applied to real-system included non-linear,irregular distribution errors.In this paper,the accuracy of UPF is proved through the simulation experiment,using the virtual-data needed for the test.     

在超声-放电复合加工机床中结合应用专家系统与实时控制系统

研制了一种超声-放电复合加工参数选择专家系统,介绍了如何结合应用该专家系统与机床实时控制系统,并作了实际加工试验。     

Measurement of the contact area of a dovetail milling cutter using an ultrasonic method

Since there is no reliable mathematical model to analyze a multi-points contact simultaneously, the most effective way to know the contact area is to use experimental method directly. This study measures the contact area between a dovetail milling cutter and a steel plate by using ultrasound for regional scanning. This is a novel application for milling cutters and has not been applied before. The transducer emits an ultrasonic pulse to detect the contact surface. If contact occurs, the pulse is partially transmitted into the specimen. Therefore, the signal reflected back to the pulse receiver is reduced. The amount by which the signal amplitude is reduced is a measure of the degree of contact.     

Development of a Web-based RCM system for the driverless Rubber-Tired K-AGT system

The Korean Railroad Research Institute (KRRI) developed the rubber-tired AGT system (Model: K-AGT) between 1999 and 2005. The K-AGT is a light rail transit system does not require a driver and generally operates on an elevated railroad for transporting passengers. Accidents caused by driverless vehicles can severely affect social confidence, safety and economy. Therefore, it is very important to minimize the occurrences of such faults, and to accurately perform detailed maintenance tasks and thoroughly investigate the cause of any repeated failures. This research develops the web-based reliability centered maintenance (RCM) system for the K-AGT train system. The framework of the RCM system is based on performing a failure mode and effects analyses (FMEA) procedure on all the sub-systems in the K-AGT system. Out of the devices that have a low reliability, the high failure ranked devices are included high on the list for performing the overall maintenance plans. Through registration of historical failure data and the reliability indexes, the results of the FMEA can be updated. Such a process is repeated continuously and can achieve very accurate predictions for device operational lifetimes and failure rates. Also, the RCM system is designed so that workers can refer to the expert system for the latest procedures to perform the required diagnosis and repair of any failure. The overall RCM system consists of a failure/task management system, a preventive maintenance system, an expert system, a material management system, and an approval system. This research describes the development of the preventive maintenance system and the expert system that have been produced because these are the main functions for the RCM system. This paper was recommended for publication in revised form by Associate Editor Dae-Eun Kim Myung-Won Suh is a Professor of Mechanical Engineering. During 1986–1988, he worked for Ford motor company as researcher. From 1989–1995, he worked in technical center of KIA motors. He took a BS degree in Mechanical Engineering from Seoul National University and an MS degree in Mechanical Engineering from KAIST, South Korea. He obtained his Doctorate at the University of Michigan, USA, in 1989. His research areas include structure and system optimization, advanced safety vehicle and reliability analysis & optimization. Chul-Ho Bae is a PhD candidate at Sungkyunkwan University in Suwon, South Korea. He accomplished fellowship work as researcher at Mississippi State University, USA, in 2003 and 2005. He worked in Institute of Advanced Machi-nery and Technology (IMAT) as a Research Assistant in 2004. He was a part time Lecturer in computer aided Mechanical Engineering of Ansan College of Technology, Suwon Science College, and Osan College during 2004–2005. He took a BS Degree in Mechanical Design and an MS Degree in Mechanical Engineering from the Sungkyunkwan University. His research interests include computer aided engineering, reliability engineering, and optimization.     

高速单像素相机数据采集系统

研究了在压缩感知基础上发展起来的3D单像素相机的成像机制。基于现场可编程的阵列(FPGA)和FMC子板设计了一种可以代替雪崩光电二极管(APD)单光子探测器的高速3D单像素数据采集系统,以提高现有3D单像素相机系统的数据采集速度、降低系统成本。该系统基于Xilinx公司的FPGA和4DSP公司的FMC126子卡,配合高速光电探测器来实现对光信号的高速采集,同时获得目标物体反射光的光强信息和纵向距离信息,其采样率为5GS/s、分辨率为10bit。系统采用脉冲采样模式,最大程度地降低了数据量和计算成本。实验结果表明:在用800ps半脉宽的脉冲激光器作为光源时,可以得到20cm以上的纵向分辨率,每次数字微镜阵列(DMD)调制后的采集时间由目标物体的纵向长度决定。该系统也适合激光三维成像,脉冲激光测距等方面的应用。     

移动相机下基于三维背景估计的运动目标检测

室内环境中的运动目标检测是计算机视觉领域的研究热点,而移动相机造成的动态背景是运动目标检测的难点。本文提出一种基于同步定位与地图创建(ORB-SLAM)三维背景估计的运动目标检测算法,首先使用移动相机遍历整个室内环境,采用ORB-SLAM技术建立当前全局环境的三维背景特征点云模型;然后基于局部视频建立局部三维特征点云,根据定位信息将当前局部三维特征点云与环境三维背景特征点云进行嵌入,基于环境背景信息,采用三维均值漂移(3DMS)算法,对局部三维特征点云进行前景特征点提取;运用深度卷积神经网络,对提取的前景特征点所在候选区域进行运动目标确认。通过多个室内场景的实际实验进行验证,结果表明本文方法具有较高的运动目标检测准确率和召回率,提出的运动目标检测算法充分利用了三维背景信息,采用深度卷积神经网络进行确认,有效地改善了检测的准确性和鲁棒性。     

在线检测挥发性有机物的质子转移反应飞行时间质谱仪的研制

基于质子转移离子源和飞行时间质谱分析器技术,自主设计和开发了质子转移反应飞行时间质谱仪(PTR-TOF MS)。该仪器主要由空心阴极放电区、质子转移反应管、离子传输区及飞行时间质量分析检测器4部分组成。为了增加离子的传输效率,提高仪器的性能,整个仪器的真空系统采用三级真空设计,分别对应于质子转移反应管、离子传输区和飞行时间质量分析器。离子在离子传输区的运动轨迹通过Simion程序进行了模拟和优化。采用不同浓度的甲苯标准气体对仪器的整体性能进行测试,该仪器的线性动态范围可达3个数量级,检测限可达5×10^-10(甲苯)(S/N=6),分辨率优于4 500。