该文针对左、右对称分布蜂窝库结构以及重载托盘,设计了一种三自由度机械手及其测控系统,可将此类管材存取于横梁式货架蜂窝库中.为减轻托盘自重,其底盘采用了刚度较大的框架结构减小弯曲变形,两侧受力较小,采用分布式立柱实现挡料;通过霍尔传感器实现移载小车减速位及机械手允许旋转位的检测,通过机械开关实现机械手臂摆动到位检测,以及手腕扭转到位检测;在机械手手掌上安装了漫反射光电传感器,利用传感器的迟滞特性实现了机械手对于托盘拉杆的精确定位和柔顺抓取.给出了移载小车和机械手的结构设计,以及三相交流电机和直流电机的驱动控制策略.系统实现了3000 kg负载托盘的快速、可靠存取,移载小车纵向定位误差为 1 mm.

针对工业现场使用压电超声波检测焊缝缺陷时需使用耦合剂的问题,研究了通过无须耦合剂的基于磁致伸缩电磁超声对薄钢板焊缝中缺陷进行检测的方法,并且针对电磁超声换能效率低、信号微弱的问题,通过仿真优化了回折线圈结构参数,选择了三分裂回折线圈,并探究了导波频率对缺陷检测灵敏度的影响.仿真结果表明:相比于无分裂线圈,选择三分裂回折线圈后激励信号面内位移幅值提高了94.2%,随着导波频率增加,缺陷反射回波幅值表现出先增大再减小的变化规律.实验结果表明:S0 模态Lamb波垂直入射焊缝时,焊缝本身产生的回波与缺陷信号相比相对较小,缺陷检测阈值达到1 mm,缺陷定位误差小于2 mm,证明了电磁超声导波具备检测焊缝中毫米级缺陷的能力.

The magnetostrictive properties of ferromagnetic materials are related to their microstructure which varies between different stress states. This paper proposes a new method of stress detection based on EMAT (electromagnetic ultrasonic transducer) to better identify the early defect and stress state of materials. For experimental verification, an experimental platform consisting of cantilever beam, strain gauge and EMAT detection system was constructed. Compared with the traditional method of magnetostrictive effect detection, the transmitter and the receiver were deployed in 7 different ways to explore the relationship between electromagnetic ultrasonic signal and stress. According to the amplitude of EMAT signal and the intensity of magnetic field as obtained under different stress states, the relationship curves between them were drawn, with ten representative EMAT characteristic parameters selected. In addition, BP (back propagation) neural network was applied to establish the mapping relationship between the electromagnetic ultrasonic characteristic parameters and the stress state of the specimen, and the material stress was predicted with the maximum error of 8.10%. Moreover, BP neural network was adopted to combine EMAT characteristic parameters with Barkhausen characteristic parameters for establishing the mapping relationship between the characteristic parameters and stress state of specimen. The research results show that the accuracy of quantitative prediction was improved for material stress, with the maximum error reaching 6.27%.

The measurement of mechanical properties parameters has been found as the standard process to predict the quality of ferromagnetic materials, which is a critical step in the production of ferromagnetic materials. The conventional testing methods of mechanical properties are dependent on Destructive tests. In this study, a nondestructive method was proposed based on magnetostriction EMAT and sound velocity to measure the mechanical properties of ferromagnetic materials imprinted by the materials' microstructure since the microstructure can have an effect on the pattern of the magnetostrictive effect and sound velocity of ferromagnetic materials. For experimental verification, the ultrasonic propagation time was calculated by filtering the orthogonal demodulation of the electromagnetic ultrasonic signal. Based on BP (back propagation) neural network, the Mean Impact Value (MIV) of each characteristic value was investigated to predict the effect arising from sound velocity on the network output. Moreover, with GRNN (general regression neural network), this study established the mapping relationship between magnetostrictive parameters (with or without combined sound velocity) and mechanical properties of the material, and the mechanical properties of the materials were non-destructively measured. The testing samples of cold-rolled steel specimens synthesized by Bao-steel Inc. were verified. As indicated by the results, the method combined with sound velocity achieved higher prediction accuracy, and the passing rate of relative error less than 10% could reach 95%.

拉线位移传感器将拉绳的位移转变为滑轮的转动,通过角度测量得到拉线自由端的位移,安装方式和使用环境都会对测量结果产生影响.本文基于拉线位移传感器的工作原理建立了拉线的力学模型,分析了误差影响因素,同时分析了其角度测量部件-增量式旋转编码器引入的误差.由于目前比较普遍使用的误差补偿模型优化算法难以获得较好的补偿效果,本文提出了一种基于粒子群算法(PSO)优化的BP神经网络模型的误差补偿方法.以KS120系列拉线位移传感器为研究对象,进行了实验研究,结果显示:在全量程范围内,使用该方法进行误差补偿后的拉线位移传感器精度由0.136％FS提高到0.007％FS,提高了95％.最后将本模型与基于多项式拟合算法和传统BP神经网络算法的补偿系统进行实验对比,结果显示补偿效果亦优于这两种方法.

2D/3D integrated circuit packaging technology is adopted in the process of wafer packaging and this technology uses wafer bumps to connect active devices. Inconsistent bump heights will cause circuit break after packaging, which will cause the whole chip to fail. Therefore, on-line detection of the height consistency of bumps is required during wafer packaging. To meet the above requirements, a fast and high-precision bump height measurement method based on optical triangulation method is studied. Based on the basic principle of oblique incidence optical triangulation method, the line beam is projected onto the chip bump, and the reflected beam on the chip surface is collected by the camera after through the imaging system. The height of the bump is calculated according to the geometric characteristics of the light stripe in the image collected by the camera and the distance between the spot on the top of the bump and the light stripe. Compared with spectral confocal method and white light interferometry, this method has the advantages of high speed and high measurement efficiency, and can meet the needs of on-line measurement of chip packaging defects. When calibrating the parameters of the chip bump height measurement system, in order to solve the difficult problem of angle calibration of projection and imaging device in the traditional triangulation method, a new calibration method is adopted: the magnification and pixel height ratio of the imaging system are used to replace the device angle to realize the indirect calibration of angle parameters. In order to accurately calibrate the pixel height ratio, a laser interferometer is used to accurately measure the height deviation of the reference plane. The center coordinate of the light strip on the reference plane is extracted by the gray centroid method to obtain the center offset of the light strip. The pixel height ratio is calculated according to the center offset of the light strip and the height deviation of the reference plane. A high-precision circular calibration plate is used to calibrate the magnification of the imaging system. The Hough circle transformation algorithm is used to extract the center coordinates of the circular pattern, and the magnification of the imaging system is calculated according to the ratio of the center distance of adjacent circles in the image to the actual distance. By substituting the calibrated system parameters into the measurement model, the accurate measurement of chip bump height can be realized. Using this method, the chip bump height is measured, and the standard deviation of height measurement is 0.58 mu m. If the same bump is measured repeatedly, the extension uncertainty is less than +/- 1 mu m. The experimental results show the accuracy of the measurement method. Compared with the traditional optical triangulation method, the chip bump height measurement model proposed in this paper is not affected by the light strip position and width, and the measurement accuracy and speed have been further improved. The research results of this paper are of great significance to realize the rapid and accurate detection of chip bumps, and have a strong reference value for the height measurement of objects with spherical structure at the top. This measurement method combined with high-precision mobile platform can further measure the bump height of chip or wafer, so as to evaluate the bump height consistency. Therefore, this measurement method has important application value for the research of industrial on-line bump height consistency measurement system.

Remanence detection is a technique of electromagnetic non-destructive testing (NDT). This paper studies a quantitative detection method for surface cracks of ferromagnetic materials based on remanence. The finite element analysis software COMSOL Multiphysics was used to establish the remanence detection model and the 'moving grid' function was used to realise the simulation of the remanence signal. The leakage magnetic field occurs due to the distortion of the magnetic induction lines near the surface cracks after ferromagnetic materials are magnetised. Remanence detection uses the leakage magnetic field to detect cracks. The relationship of the leakage magnetic field versus the crack depth and width was analysed using the magnetic dipole model. The relationship between the crack size and the remanence signal was verified by measuring the surface remanence signal of cracks of different sizes. The characteristic parameters related to the crack size were extracted and the regression model between the characteristic parameters and the crack size was established. For the remanence detection, the maximum error of width prediction was 16.25% and the maximum error of depth prediction was 18.48%. For the magnetic flux leakage (MFL) detection, the maximum error of width prediction was 12.1% and the maximum error of depth prediction was 12.32%. Under the same experimental conditions, the maximum error of crack width measurement of remanence detection was 4.15% larger than that of MFL detection and the maximum error of depth was 6.16% larger than that of MFL detection.

城市轨道列车使用的气路管材来自长细管的切割、弯曲等加工工艺过程.从托盘自动拣选到加工工位需要保证管材不产生塑性形变.该文针对不锈钢长管材的自动拣选搬运需求,研究了多支拣选机械手同步控制技术,利用主从控制方式,通过射频通讯技术实现多个机械手的动作准同步控制;采用分解动作同步策略,降低了机械手运动环节的误差积累,提高了管件搬运过程的平稳性,根据实验验证该方法具有可行性.

Ferromagnetic materials are widely used in industry and risking the hazards of aging and degradation of their mechanical properties. This paper proposed a non-destructive method for the measurement of the yield strength of ferromagnetic materials imprinted by the materials’ microstructure as the microstructure influences the pattern of the inverse magnetostrictive effect of ferromagnetic materials. For experimental verification, yield strengths of ferromagnetic specimens were measured on an electromagnetic ultrasonic transducer (EMAT) detection system. The relationship between electromagnetic acoustic transducer signals and the static magnetic field strength was obtained, from which we extracted the pattern parameters related to the yield strength. The regression model of the pattern parameters versus the yield strength was established and then verified with trial on a specimen processed in the same batch with a maximum prediction accuracy of 12.78%.

在工程教育专业认证及新工科教育背景下,以南京航空航天大学测控技术与仪器专业的传感器原理课程教学为例,开展培养学生解决复杂工程问题能力的课程改革实践.改革实践依据工程教育专业认证的要求和本专业的培养目标,建立了包含知识学习、技能培养、内容设计和考核评价的"培养解决复杂工程问题能力"的教学体系.

The mechanical and micromagnetc properties of ferromagnetic materials are overall associated with their microstructure parameters. The magnetostriction refers to one of the micromagnetic properties. The magnetostrictive properties of ferromagnetic materials are characterized by the relationships between the intensity of the SH (Shear Horizontal) waves with magnetostrictive effect under the identical excitation and the static bias magnetic induction intensity. In this study, the characteristic parameters exhibiting sensitivity to the magnetostrictive properties of ferromagnetic materials in the relationships between the intensity of EMAT (electromagnetic acoustic transducer) signal and static magnetic field strength were extracted. Besides, with BP (back propagation) neural network, the mapping association between the magnetostrictive parameters and the mechanical properties of the materials was developed, and the mechanical properties of the materials were non-destructively determined. By verifying the testing samples of cold-rolled steel specimens synthesized by Bao-steel Inc., the method was found to be capable of achieving high prediction accuracy; the passing rate of relative error less than 10% can reach 90%. (C) 2020 Published by Elsevier Ltd.

Non-destructive testing (NDT) involving stress measurement has found a wide range of applications in rail, pipeline, bridge and other engineering areas and it is therefore necessary to find a method to measure stress. In this paper, a non-destructive method is proposed to measure stress by observation of the magnetostrictive properties of the objects. Stress in the elastic range is applied to the ferromagnetic material, changing its lattice, while stress in the plastic range changes its microstructure. These are the reasons for the magnetostrictive coefficient variation of the material. An experimental platform was set up, using a cantilever beam with a strain gauge, to study the relationship between the SH wave, the static magnetic field strength and the applied uniaxial stress. The curve obtained shows the relationship between the amplitude of the electromagnetic acoustic transducer (EMAT) signal and the static magnetic field strength. The magnetostrictive parameters, sensitive to stress, were extracted from the curve. This method is verified through trials on test samples with a maximum relative error between experimental and predicted values of 8.06%.

Metal magnetic memory (MMM) is a widely used non-destructive electromagnetic detection technology. However, the analysis of its underlying principle is still insufficient. The mechanical and magnetic coupling model is a reasonable standpoint from which to study the principle of MMM. In this paper, a mechanical and magnetic coupling model of steel material is established based on density functional theory (DFT) using the CASTEP first-principles analysis software. In order to simulate the practical working environment, the residual magnetism in the rail is assumed to change with the stress on the rail. By applying different stresses to the model, the relationship between the atomic magnetic moment, the lattice constant and stress is explored, as well as the causes of magnetic signals in the stress concentration zone. It is revealed that the atomic magnetic moment and the crystal volume decrease with the increase in compressive stress. The magnetic signal on the surface of the magnetised metal component decreases with the increase in compressive stress, while the tensile stress shows the opposite tendency. Generally speaking, the change in atomic magnetic moment and crystal volume caused by lattice distortion under stress can be seen as the fundamental reason for the change in magnetic signal on the surface of the magnetised metal. The bending experiment of the rail shows that the normal magnetic field decreases with the increase in compressive stress in the stress concentration zone. The conclusion is verified by experiments.

压电式传感器与其他传感器相比,具有体积小、重量轻、频带宽和动态特性好等特点.基于压电材料的传感器实验是测控技术与仪器专业实验课程设计中的一个重要环节.以南京航空航天大学测控技术与仪器专业的传感器原理课程实验为例,设计了基于激振台和压电悬臂梁晶片的振动能量采集实验,帮助学生通过压电能量采集实验了解压电效应,并学会利用有限元软件进行压电悬臂梁的应力仿真分析,灵活应用常用的能量采集电路,实现高效率的能量采集,进而提高学生对压电材料和基于压电材料的传感器的理解和实践应用能力.

高速载运设施事关国家命脉,在其生产、布设、使用和维护各个环节,都需无损检测技术保驾护航.本文就高速载运设施无损检测的必要性,检测现状、检测技术的发展趋势(包括基于多物理原理的新型伤损检测技术,材料应力、微观结构、机械性能等状态检测,以及无损检测和结构健康监控及人工智能的结合)进行综述,旨在为高速载运设施的无损检测打下基础.

以STM32F013VET6为主控芯片,设计并实现了一种气动机械手位置伺服控制器.该控制器在STM32微处理器基本外围电路的基础上设计了开关量输入输出接口、模拟量输入输出接口、RS232通信接口、电源模块及nRF24L01无线通信模块.在控制策略的选取上,采用模糊PID控制算法,利用模糊规则对常规增量式PID控制算法进行在线参数自整定.对气动机械手进行了位置伺服控制实验研究,对比了相同目标位置下不同工作环境常规增量式PID控制位置响应曲线和模糊自整定PID控制位置响应曲线.实验结果表明,所设计的控制器具有通用性好、性价比高、控制精度高、响应快、实时性好等优点,并且具有良好的工作环境自适应能力.

在分析玻璃钢夹砂管道典型缺陷的基础上,分别采用DR检测技术、相控阵检测技术对其典型缺陷进行了无损检测研究.检测结果表明:DR检测技术能够有效地检测出试件的体积型缺陷,而对于复合材料层合结构中典型分层类缺陷正面检测时不易发现,只能通过侧面检测辅助判断;超声相控阵检测技术可以检测出试件中的气孔类体积型缺陷以及分层类缺陷,但由于在复合材料层合结构中声波衰减严重,本研究中采用的2.25MHz频率的探头只能检测到玻璃钢-夹砂层界面以下深度约15mm处回波.这说明2.25MHz频率超声探头不能够穿透该复合材料,不适用于该类复合材料管道的检测,需要探索更低频率的探头对其进行检测验证.

The sensor principle course in major of measurement and control technology and instrument of Nanjing University of Aeronautics& Astronautics has been taken as an example to discuss the setting and implementation scheme of sensor courses under the general standard of engineering certification. It puts forward that the course should aim at improving the ability of students' professional skills and solving complex engineering problems, and increase innovative study cases to enable students to consider other restrictive factors such as cost, environment protection, etc. The students need master the use of common sensors and accomplish the design and implementation of sensor systems, improve the ability of practice and innovation. Abstract: Under the background of electronic information engineering professional engineering education accreditation, in order to solve the problems appeared in the course design of electronic technology, based on OBE educational concept, this paper has carried on the reform and research from the setting of teaching objectives, teaching model optimization and complete the assessment method, and the benefit of the reform is analyzed. The results show that students' self-learning ability, innovation ability and problem solving ability have been improved.

铁磁性材料的微观结构状态会随工作应力而发生改变,微观结构的改变会引起材料的磁致伸缩特性发生变化.设计了一种基于磁致伸缩机理的电磁超声换能器(EMAT)应力检测系统.利用磁致伸缩效应强烈依赖于材料的微观结构状态以及工作应力的特性,设计了一个悬臂梁实验装置,以应变片检测构件的应变作为参考值,分析磁致伸缩EMAT接受的SH波的幅值信号、静态磁场强度与应力的关系.选择A3钢试件,绘制不同应力情况下的超声信号幅值-磁感应强度关系曲线.实验结果表明,在不同的应力状态条件下,超声信号幅值-磁感应强度关系曲线的特征参数呈现单调变化.

风机叶片表面在出现损伤时,叶片在空气中转动过程中,产生的气动音频信号有异于叶片无损时的气动音频信号,其信号特征参数与叶片的损伤类型存在一定的关系,但风机叶片在空气中旋转产生的气动音频信号往往是非线性非稳态的,对于这种信号的特征提取存在一定困难,实验证明,正常叶片气动音频信号与故障叶片的气动音频信号的频带存在显著差别,基于此,提出一种基于ITD固有时间尺度分解的时频分析方法,先将信号自适应的按频率从高到低分解为若干PRC旋转分量,计算每一频带内的时域信号的能量,构造初始特征向量,再使用PCA对特征向量进行降维,简化计算,提高分类器识别效率,最后将降维简化后的样本特征向量输入到支持向量机进行训练识别,并从特征提取时间和识别率上与传统EMD分解作比较,结果表明,该算法降低了特征提取的计算量,减少了特征提取时间,且有更高的识别率.