漏磁检测多排传感器的数据修正理论及方法

漏磁检测因其显著的技术优势,被广泛应用于无损检测铁磁性构件中的缺陷,尤其是在油气管道的内检测领域。 漏磁 检测信号的空间分辨率由传感器的排布密度决定,但传感器的排布密度受其尺寸限制,尤其是对单排传感器。 因此为提升检测 信号的空间分辨率,传感器的多排、错排布置是简单易行的方法。 由于多排传感器所处位置的背景磁场不同,不同背景磁场对 检测信号的影响规律尚不清晰,因此需要对以上问题进行理论分析,并提出对多排传感器检测数据进行修正的方法。 本研究基 于磁荷理论,将缺陷检测信号划分成背景磁场和缺陷漏磁场两部分的叠加,给出了两者叠加的规律。 基于此提出了对多排传感 器的检测数据进行修正的方法,并通过 COMSOL 仿真和实验结果验证了所提方法的有效性。     

全波形激光测距幅相误差改正方法

针对全波形激光测距中存在的幅相误差问题,提出一种基于神经网络的幅相误差改正方法。利用非合作目标探测信息,通过提取回波波形的形状信息、能量信息、梯度信息、对称性信息及距离信息特征参数,根据皮尔逊相关系数对特征参数进行分级,建立多回波特征信息与幅相误差改正的神经网络模型以校正全波形激光测量中各通道幅相误差的影响。实验使用5%、20%、60%、80%标准反射板及激光采集模块在室内对7种距离进行数据分组采集和处理,并与传统测量方法进行对比。结果表明,该方法可以有效减小全波形激光测量中幅相误差的影响,测量精度提高了51.2%以上。     

Design and real time implementation of single phase boost power factor correction converter

This paper presents a real time implementation of the single-phase power factor correction (PFC) AC–DC boost converter. A combination of higher order sliding mode controller based on super twisting algorithm and predictive control techniques are implemented to improve the performance of the boost converter. Due to the chattering effects, the higher order sliding mode control (HOSMC) is designed. Also, the predictive technique is modified taking into account the large computational delays. The robustness of the controller is verified conducting simulation in MATLAB, the results show good performances in both steady and transient states. An experiment is conducted through a test bench based on dSPACE 1104. The experimental results proved that the proposed controller enhanced the performance of the converter under different parameters variations.     

一种SMT生产缺陷自动检测系统的设计与实现

为了控制PCB成品质量,设计和实现了对SMT生产缺陷的自动检测。采用定位、摄像和图像处理等技术,精确检测和标识PCB产品的缺陷。系统运行可靠,降低了SMT生产成本。     

远程气象探测系统设计与实现

大气参数是大气科学各种理论研究的基础,其最直接的测量方式就是通过雷达或无线电经纬仪进行高空探测,但是,这些设备存在探测距离有限、不能空投、不能多个探空仪同时探测等缺点。文章介绍了一种远程综合探测系统的设计方案与实现方法。该系统具备远程自动探测能力,能实现远程监测、高度可控、定点投送功能,并具备完善的数据处理和气象辅助决策功能。通过对远程综合探测系统的试验和仿真,验证了其功能和性能达到了设计要求。     

一个连续码版面喷印系统的设计与实现

本文阐述了对一台喷码机进行功能扩展,以实现按版面喷印连续码的软硬件设计思想与实现过程,系统的实现综合了机械,单片机,喷码机,串型通信,多线程等方面技术,用较低成本换取到很好的经济效益。     

高速卷绕头网络控制系统的设计与实现

主控机、工控机、可编程逻辑控制器(PLC)和变频器(FC)构成的网络控制系统中，利用RS-232与RS-485接口实现主控机、工控机、可编程逻辑控制器和变频器之间的通信，具有成本低，易于实现多机联网控制．抗干扰能力强等优点。本文主要介绍了RS-232接口通信系统的设计方法与实现。     

正压法气体流量标定系统的设计与实现

随着非标准流量仪表种类和数量的日益增加,为了保证仪表的测量精度。非标流量仪表的标定要求显得日益迫切。系统采用了国际标准文丘利作为标准表。应用标准流量计“比较法”原理,配合计算机程序控制,建立气体流量标定系统。进行流量计的检定和测试。依据有关的国家检定规程。该装置可对多孔孔板、V锥、楔形、巴类等差压式仪表以及涡轮、涡街、旋进旋涡等流量计进行检定、工业现场流量模拟实验以及风洞实验。通过运行实践证明,该系统测量精度高,稳定性好,标定流量范围宽。     

鸭舵式二维弹道修正机构设计与动力学分析

提出并设计了一种新型的二维弹道修正机构,建立了动力学分析模型,并通过仿真分析,验证了新型修正机构的可行性及合理性.分析结果表明,该修正机构具有响应时间快、结构简单、同步性好、动作可靠等优点,满足对二维弹道修正能力的要求.这将为二维弹道修正结构的进一步设计和试验奠定良好的基础.     

痕量N2O气体检测系统的设计与实现

建立了基于光谱吸收技术的检测系统,用于快速、准确地测量N2O气体浓度。首先,从理论上证明了二次谐波、一次谐波与N2O气体浓度之间的关系;然后,设计了痕量N2O气体浓度检测系统,利用光源调制、锁相放大等技术,实现了强杂波背景下气体浓度弱信号的解析;最后,实验测试了系统的检测性能、抗干扰能力及检测结果的可重复性。测试结果表明,系统能够在0～1%有效检测N2O气体浓度,检测下限为5.0×10-5,相对检测误差为0.11%,检测结果线性方程为Y=192.699 09 X-0.006 24,线性度为0.998 07。多次检测实验表明,系统相对标准偏差为0.137%,CO2、O2、水蒸气等常见气体对检测结果无影响。改变激光器的中心波长,该方法亦可用于CO2,CH4等其它温室气体的检测。     

用坐标法在数控机床上加工管板类工件的管孔位置度误差研究

以坐标法在立式加工中心加工大型管板类工件上的管孔为例,说明了工序尺寸链组成.对单个孔的位置度极限误差、任意两孔的中心距尺寸极限误差及其影响因素进行了分析,得出了单个孔的位置度极限误差、任意两孔的中心距尺寸极限误差与被加工孔在机床坐标系中的位置有关、与工件的移动路径和加工顺序无关的结论,对合理评价被加工件的质量具有普遍的指导意义.     

Design and implementation of an ultrasonic sensor for rapid monitoring of industrial malolactic fermentation of wines

Ultrasound is an emerging technology that can be applied to monitor food processes. However, ultrasonic techniques are usually limited to research activities within a laboratory environment and they are not extensively used in industrial processes. The aim of this paper is to describe a novel ultrasonic sensor designed to monitor physical–chemical changes that occur in wines stored in industrial tanks. Essentially, the sensor consists of an ultrasonic transducer in contact with a buffer rod, mounted inside a stainless steel tube section. This structure allows the ultrasonic sensor to be directly installed in stainless steel tanks of an industrial plant. The operating principle of this design is based on the measurement of ultrasonic velocity of propagation. To test its proper operation, the sensor has been used to measure changes of concentration in aqueous samples and to monitor the progress of a malolactic fermentation of red wines in various commercial wineries. Results show the feasibility of using this sensor for monitoring malolactic fermentations in red wines placed in industrial tanks.     

星载超光谱成像仪摆镜系统轴系的误差分析与设计

摆镜系统轴系的精度会影响星载超光谱成像仪的成像质量。轴系设计时采用了向心推力球轴承来调整轴系的装配误差。分析了摆镜系统工作时影响轴系精度的几个误差源,包括零件的尺寸误差、同轴度误差、配合误差等,按照误差理论设计并计算了各误差值,得到轴系的径向晃动误差和角运动误差。对加工好的轴系进行精度检测,实验结果符合理论结果,验证了该摆镜系统的轴系结构设计的合理性和可靠性,为该类航天运动部件的轴系结构设计提供了参考依据。     

基于 Lamb 波的数据传输与缺陷检测同步实现方法

在结构健康监测领域,超声导波相对于体波具有传输距离远、覆盖范围大、检测成本低的优点。提出了一种基于Lamb波的数据传输与缺陷检测同步实现方法,实现了超声系统的多功能复用。通过理论仿真与扫频实验验证了Lamb波模态调制理论,使用压电晶片主动传感器在铝板上以500 kHz的中心频率激发出S₀模态Lamb波进行数据传输和缺陷检测。针对Lamb波边界反射引起的码间串扰问题,采用移不变稀疏编码方法进行信息恢复,在具有反射边界的铝板上成功实现100 kbps的信息传输速率,并且误码率为0。同时,利用移不变稀疏编码中的原子信号进行结构缺陷检测,根据合成孔径聚焦技术实现了缺陷的准确定位,定位误差小于0.2%。     

基于虚拟传感器的气体传感器故障诊断与恢复

对传感器进行故障检测与恢复,对提高系统可靠性是必须的。采用智能软方法可以有效地降低系统的成本。由于化学气体传感器之间具有信息冗余的特点,该文提出了利用神经网络构建虚拟传感器来实现化学气体传感器故障检测与恢复的新方法,该方法已用于一个人工嗅觉系统中,实验表明采用该方法可以方便地实现传感器故障的在线诊断与恢复。     

Research on dynamic transmission error of harmonic drive with uncertain parameters by an interval method

Transmission error is one of the most important performance indicators for evaluating harmonic drives, and can have crippling effects on positioning accuracy and stability of industrial robots. However, most of the existing error analysis methods focus on a single factor, and do not consider the uncertainty of dynamic parameters, leading to evident limitations. In the present study, static transmission error (caused by manufacturing and assembly error) and dynamic transmission error (generated by static transmission error and dynamic parameters) of a harmonic drive are modeled. An interval method is developed and used to numerically express uncertain dynamic parameters of the system. Chebyshev polynomials are used to approximate the dynamic differential equations of the harmonic drive, and then the distribution of dynamic transmission error and its relationship with uncertain parameters are discussed in detail. In addition, a global sensitivity analysis is carried out to intuitively demonstrate how much impact each parameter has on dynamic transmission error. Our results suggest that the moment of inertia J_in and the torsional stiffness coefficient k₁ have a large influence on dynamic transmission error. Finally, the proposed method is validated by experiment. The method can be adopted to determine the upper and lower bounds of dynamic transmission error of dynamic systems under the influence of uncertain parameters and provides a theoretical basis for transmission error optimization and compensation.     

高信噪比微流控芯片检测仪的设计

简要介绍了微流控芯片及其现有的检测方法,重点设计研发一种具有高信噪比的检测仪。此检测仪器采用激光诱导荧光检测原理;检测光路采用共焦原理;并通过电路滤波及放大设计、仪器结构设计、软件设计等途径而研制。此检测仪是集光、机、电及软件处理等的多维一体的综合性仪器。检测证明这种仪器检测性能高、结构紧凑便于携带、具有很高的信噪比,检测能力可达到1-0 9n m o l/L。     

A novel concept of automatic soap flowmeter with bubble detection by closing an electrical circuit

A novel accurate method of automatic timing of bubble motion through the measuring section of a soap flowmeter is proposed. The method is based on the closure of an electrical circuit by a soap bubble moving in the calibrated tube. The accuracy of the automated flowmeter, estimated by comparison with other accurate flow measurement methods, is found to be 2%. Modification of the bubble making system aimed at increasing of the flowmeter tightness and bubble quality is developed, as well. The proposed design does not require precise assembly and admits the use of cheap and readily available components.     

Mapping and correction of the CMM workspace error with the use of an electronic gyroscope and neural networks—practical application

The article presents the application of neural networks in determining and correction of the deformation of a coordinate measuring machine (CMM) workspace. The information about the CMM errors is acquired using an ADXRS401 electronic gyroscope. A test device (PS‐20 module) was built and integrated with a commercial measurement system based on the SP25M passive scanning probe and with a PH10M module (Renishaw). The proposed solution was tested on a Kemco 600 CMM and on a DEA Global Clima CMM. In the former case, correction of the CMM errors was performed using the source code of WinIOS software owned by The Institute of Advanced Manufacturing Technology, Cracow, Poland and in the latter on an external PC. Optimum parameters of full and simplified mapping of a given layer of the CMM workspace were determined for practical applications. The proposed method can be employed for the interim check (ISO 10360–2 procedure) or to detect local CMM deformations, occurring when the CMM works at high scanning speeds (>20 mm/s). SCANNING 35: 222‐231, 2013. © 2012 Wiley Periodicals, Inc.     

Development of a new lapping method for high precision ball screw (2nd report): Design and experimental study of an automatic lapping machine with in-process torque monitoring system

This paper presents a new approach in lapping process in making appropriate condition to improve the manufacturing operations for ball screw. After grinding, high precision ball screw is lapped by highly skilled operators. These operators have the ability to control and maintain the lapping conditions by sensing the lapping torque manually. Prior to lapping process, the effective diameter must be measured to find out the effective threaded profile along the screw shaft. The section which has a large effective diameter will be primarily lapped wherein the lapping torque is high. The aim of this study is to establish a control scheme on the automatic lapping machine for high precision ball screw in both measuring and finishing process. A prototyped horizontal lapping machine with in-process torque monitoring system has been designed, built, and tested. This is to determine the relationship among lapping torque, effective diameter, and error on travel to establish the measurement system to control the finishing operations efficiently and eventually improve and eliminate the various sorts of error components in a ball screw. The experimental results showed that the new lapping method could adequately predict the effective diameter and error on travel by observing the lapping torque.