Dynamic Balancing Structure Optimal Design for the Rotating Arc Sensor

Rotating arc sensor is a key device for automation welding. The vibration has a big influence on signal's correct collection and reliable automatic welding. In order to solve the vibration problem and the dynamic balancing design with the restricted space,a bearing force analysis based dynamic balancing structure optimal design is proposed and implemented with the help of Pro/Engineer( PROE) and automatic dynamic analysis of mechanical systems( ADAMS) virtual prototype technology, in which three parameters of the counterbalance are considered. The method is suitable for the practical online adjustment. The simulation result shows that optimal design based counterbalance structure and parameters can satisfy the space requirement with lower vibration. The methodology provides a new idea for dynamic balancing design and adjustment of rotating arc sensor with adjustable rotation radius.

Short-circuit process model in underwater welding using rotating arc sensor

In order to detecting and tracking along the weld seam with rotating arc sensor in underwater welding,the highpressure water environment rotating arc welding hardware platform is established and welding experiments using rotating arc sensor is done. Different radius of rotating arc sensor is used. And the corresponding welding current and voltage is obtained,which is compared with the results of rotating arc sensor short-circuit process simulation model under high-pressure water environment established in this article. The results show that under high-pressure water environment,rotating arc radius should be optimized,otherwise the short-circuit-arcing cycle will transit to a short-circuit-arcing-abruption cycle,making the welding quality poor. At last the critical radius between the short-circuit-arcing cycle and short-circuit-arcing-abruption cycle under high-pressure water environment is obtained.

Simultaneous observation of keyhole and weld pool in plasma arc welding with a single cost-effective sensor

The dynamic behaviors of the keyhole and weld pool are coupled together in plasma arc welding, and the geometric variations of both the keyhole and the weld pool determine the weld quality. It is of great significance to simultaneously sense and monitor the keyhole and the weld pool behaviors by using a single low-cost vision sensor in plasma arc welding process. In this study, the keyhole and weld pool were observed and measured under different levels of welding current by using the near infrared sensing technology and the charge coupled device （CCD） sensing system. The shapes and relative position of weld pool and keyhole under different conditions were compared and analyzed. The observation results lay solid foundation for controlling weld quality and understanding the underlying process mechanisms.

基于BP神经网络薄板P-PAW搭接的间隙自适应工艺参数优化

对大型LNG燃料薄膜舱中1.2 mm厚SUS304L不锈钢板薄板的搭接焊,存在的搭接间隙会带来焊缝成形不良等严重影响船舱安全性的问题。本文通过激光传感器检测搭接间隙变化,设计了不同的峰值电流和焊接速度在不同间隙下的工艺实验,研究了间隙对焊缝成形质量的影响机制;基于BP神经网络建立不同间隙下的脉冲等离子弧焊(P-PAW)的工艺参数和间隙及焊缝成形尺寸之间的拓扑关系模型,通过工艺实验获取模型的训练样本,实现了基于BP神经网络的间隙自适应工艺参数优化系统。结果表明,该系统实现了不同搭接间隙下进行实时工艺参数优化的功能,并对搭接间隙在0~0.6 mm变化时所带来的空洞等缺陷起到了有效的抑制作用,实现了良好的焊接成形一致性控制,提高了在LNG薄膜舱中不锈钢板焊接的自适应能力。

脉冲电弧离子镀工艺参数对氧化锌压电涂层结构与电阻的影响

为了给探索、提升ZnO压电薄膜的制备工艺提供一定的科学参考及依据,通过脉冲电弧离子镀的方法在不锈钢基底上沉积结合力强的纳米氧化锌(ZnO)压电涂层,并系统研究工作气压及靶基距这2个关键制备工艺参数对ZnO压电传感涂层的晶体结构及电阻性能的影响。结果表明:工作气压降低则涂层结晶度提高,而随靶基距增大,结晶度先增加后降低,电阻随之降低。这一结果为新型永久薄膜压力传感器(PMTS)在高压及超高压智能套管的压力监测领域的应用提供了一定的科学参考及依据。

Application of RVM for prediction of bead shape in underwater rotating arc welding

Bead sttape in underwater rotating arc welding was affected by several welding parameters. RVM （ relevance vector machine） was used to build a model to predict weld bead shape. The training data set of RVM eortsists of the welding parameters which are rotational frequency, rotational radius, height of torch and welding current and the features of the bead shape. The maximum error and mean error for prediction of width are 0. 10 mm and 0. 09 mm, respectively, and the maximum error and mean error for prediction of penetration are 0. 31 mm and 0. 12mm, respectively, which are showed that the prediction model can achieve higher prediction precision at reasonably small size of training data set.

基于法拉第效应的宽频光学电流传感器研制及其性能研究

当前智能电网和新型电力系统中存在大量高频暂态电流分量。高频暂态电流是反映电力系统扰动及故障过程的重要信息,对其波形、频率、幅值等信息参数进行实时观测是预防和确保电网安全稳定运行的前提。而传统电流测量方式存在频带窄、易受电磁干扰、绝缘配合难度大等问题,难以对暂态电流进行有效检测。故提出并设计了一种具有抗干扰能力的螺线管式宽频光学电流传感器,基于传感器性能测试平台,研究了传感器的灵敏度、线性度以及频率特性,结果表明目前传感器的灵敏度为62.57 mV/A且带宽可以达到1 MHz以上;此外搭建了直流电弧实验平台对直流电弧进行了测量。试验结果表明,该传感器可实现对直流至高频电弧分量的有效测量,其测量结果与标准电流探头的线性相关度可达0.9971,多次实验结果表明相关系数的相对变化率小于2%,具有一定工程使用价值。

基于电磁辐射到达时差的电弧故障定位及精度

为了实现利用电磁辐射信号进行配网电弧故障定位,提出了一种基于到达时差(time difference of arrival,TDOA)方法的Chan-LM协同定位算法。该算法采用Chan算法快速获得的初始点,再经过LM(Levenberg-Marquart)算法迭代修正定位结果。仿真分析了TDOA定位算法、电磁辐射传感器配置对定位精度的影响,结果表明Chan-LM协同算法比Chan算法的定位误差减小40%,参考主站位于中心位置的Y形布站方式,传感器所在海拔高度相同时的监测区域整体定位准确度较高。利用实测电弧电磁辐射波形验证了Chan-LM协同算法能够有效改善定位精度,为基于电磁辐射TDOA的电弧定位策略应用提供参考依据。

DPR360ARC弧光保护系统设计

针对当前国内中低压母线没有快速保护的现状,设计了目前国内第一套弧光保护系统DPR360ARC,该系统采用基于紫外传感器的弧光探头技术和基于FPGA的高速串行通信技术,实现了母线、开关柜的快速保护,从弧光发生到跳闸出口的时间控制在4ms以内。DPR360ARC的应用有利于提高中低压输电线路的安全可靠性,为开关柜、母线和各种变流设备的弧光故障提供全面的保护,将对设备的损害和人员安全的威胁降至最低并确保电网平稳安全地恢复。

Some phenomena and features of the component distributions in welding arc

The components and their distributions both in space and in time are observed by spectroscopic method under GMAW and GTAW conditions.It reveals the features of component distributions in the arc as well as their regularities,and may lead to an essential knowledge to understand some physical and chemical phenomena in arc welding processes.

Micro-arc oxidization fabrication and ethanol sensing performance of Fe-doped TiO_2 thin films

In-situ pure TiO2 and Fe-doped TiO2 thin films were synthesized on Ti plates via the micro-arc oxidation （MAO） technique. The as-fabricated anatase TiO2 thin film-based conductometric sensors were employed to measure the gas sensitivity to ethanol. The results showed that Fe ions could be easily introduced into the MAO-TiO2 thin films by adding precursor K4（FeCN）6＇3H20 into the NaaPO4 electrolyte. The amount of doped Fe ions increased almost linearly with the concentration of Kg（FeCN）63H20 increasing, eventually affecting the ethanol sensing performances of TiO2 thin films. It was found that the enhanced sensor signals obtained had an optimal concentration of Fe dopant （1.28at%）, by which the maximal gas sensor signal to 1000 ppm ethanol was estimated to be 7.91 at 275℃. The response time was generally reduced by doped Fe ions, which could be ascribed to the increase of oxygen vacancies caused by Fe3＋ substituting for Ti4＋.

Study on contactless ultrasonic sensor and seam tracking

The sensitivity of contactless ultrasonic sensor is improved from 3.3% to 26% through acoustic and electric matching technique in this paper.Along dual crest lines auto seam tracking is firstly realized with contactless ultrasonic sensing.The focused acoustic lens is accurately designed, and a sonic beam with 0.5 mm in diameter is achieved. By means of software and hardware technique the accuracy of seam tracking with ultrasonic sensing is 0.5 mm in lateral direction and 0.2 mm in longitudinal direction respectively.

The validating and identifying of the droplet transfer character signal from arc light in oscillating wire feed mode

The character of droplet transfer arc light sense signal is studied and validated in oscillating feed mode. And a novel mini photoelectric arc light sensor together with the controlling circuit used to automatically stabilize the signal range is developed. Further more the automatically identifying of the droplet transfer character signal from arc light is realized reliably.

NTWV-based sensing keyhole dimension in plasma arc welding

During stable keyhole plasma arc welding, the pilot arc and the transferred arc exist at the meantime, and the arcs can be considered as a composition of two parts inside and outside the nozzle, respectively. Under the mechanical constriction and thermal contraction effects, the inside arc has certain arc length, electron density and arc profile etc. inducing constant tungsten-to-nozzle voltage. However, the arc outside the nozzle diverges at about 5 degrees and has certain characteristics similar to the free arcs. The nozzle-to-workpiece voltage （NTWV） depends mainly on the length of the arc, which gets bigger as increasing of the weld penetration and keyhole size. The NTWV sensor is developed for monitoring NTWV in real time. The welding experiments are designed to get different penetrations and keyhole sizes. It is found that as the weld penetration and the keyhole size increase, NTWV also increases linearly. The NTWV signals can be used as the feedback variable in automatic control of keyhole plasma arc welding.

Development of Magnetic Field Sensor and Motor Fault Monitoring Application

For the purpose of motor fault real-time monitoring, this research developed a nano-silicon ni- tride film based magnetic field (MF) sensor, and applied this sensor in MF detection of two common faults. Through experiment, it turned out that arc discharge and slot discharge occur in motor fault produce MF with certain laws. This result proved the feasibility of the sensor and sensing method in MF analysis, and revealed possibility of a new method in fault detection.

Pressure and Arc Voltage Measurement in a 252 kV SF_6 Puffer Circuit Breaker

The pressure distribution in an arcing chamber is critically important for the SF6 puffer circuit breaker design. In this paper, the pressure variation of four locations in the nozzle was measured by piezoresistive and fiber optical pressure sensors at two current levels of 10 kA and 50 kA. An arc voltage measurement was also taken. The results demonstrate that using either type of sensor with a connecting tube is able to detect the fast pressure variation in circuit breakers, however the possible distortion and delay to the pressure transient caused by the tube need further study.

电弧传感焊缝跟踪精度关键影响因素分析

电弧传感器根据焊接电弧信号的变化检测焊缝位置,具有无需额外设备、成本低的优点,但较低的传感精度和稳定性限制了其应用。从工程应用的角度研究焊接系统中影响电弧传感精度的因素,发现执行器发出位置信号的准确性、断弧现象、坡口角度和数据提取方式都会对传感的精度和稳定性产生重要影响,并针对性地给出了解决方案。研究结果对工程中提高电弧传感精度和稳定具有一定的指导意义。

基于弧形电容器的浆纱回潮率在线测量

为提高上浆质量以及解决使用接触式电阻含水率测量仪会破坏浆膜的问题,设计开发了基于弧形电容器的浆纱回潮率在线测量系统。根据浆纱在弧形电容器中的电场模型和电容法测量原理,利用指数回归算法建立电容差与回潮率的函数模型。上浆时,浆纱穿过弧形电容器,电感、电容、电阻(LCR)电桥测试仪将测量的电容值数据传到上位机,上位机根据模型计算出实时浆纱回潮率。讨论了弧形电容器结构、LCR电桥测试仪测试参数、环境温湿度、浆液含固率、浆纱线密度、回潮率对测量电容值的影响。实验结果表明:电容值受LCR电桥测试仪测试频率的影响较大;电容值随电容器结构参数极板长度、极板包角的增大而增大,与极板曲率半径呈负相关;环境温湿度会对电容值产生复杂影响,因此要求在恒温恒湿条件下进行测量;浆纱回潮率对电容值的影响显著,且回潮率与电容差呈指数函数关系。在上浆机上使用电容式回潮率在线检测系统进行测试,得到的浆纱回潮率与烘箱法测量结果相比平均误差小于5%,本文系统具有一定的工程实用价值。

磁控焊缝跟踪传感器非对称纵向磁场下的焊缝识别

针对纵向磁场作用下的电弧难提取焊缝信息的问题,设计一种由3个纵向分布磁感线圈组成的‘山’形分布纵向磁场传感器.利用COMSOL软件模拟非对称纵向磁场作用电弧形态.取焊接过程电弧电压分布对应的磁感应强度作为焊缝识别试验的磁感应强度.用高速摄影仪拍摄非对称纵向磁场作用下的电弧运动轨迹,并与新型传感器设计的电弧运动轨迹进行比较,验证纵向磁场传感器产生非对称纵向磁场的电弧形态变化.结果表明,非对称纵向磁场能控制电弧进行焊缝识别,并能解决窄间隙焊接过程中的咬边和侧壁不融合.该方法为磁控焊缝跟踪传感器在窄间隙焊接的应用开辟了新的方向.创新点:(1)设计一种由3个纵向分布磁感线圈组成的‘山’形分布纵向磁场传感器,该传感器产生的非对称纵向磁场能控制电弧提取焊缝信息.(2)该传感器能改变电弧热分布,从而解决窄间隙焊接过程中的咬边和侧壁不融合.

焊缝跟踪系统旋转电弧传感器的研究

随着社会的不断发展,焊接逐渐成为现代制造技术中非常重要的一个环节,在船舶制造、航空器制造、建筑业、铁路交通等领域有着越来越广泛的应用。在人们的日常经济活动中,焊接技术也有着重要的作用。手工焊接作为比较传统的焊接方式,其局限性也越来越突出,为了克服传统焊接的缺点,全方位移动焊接机器人应运而生,其中传感器是一个比较重要的部位。为了解决这一问题,文章对大型结构件的角焊缝跟踪技术进行研究,选用了旋转电弧传感器。在众多传感器中,旋转电弧传感器虽然存在着减震和小型化等问题,但是它凭借对焊缝的精确跟踪以及响应特性较高等优点实现了焊缝的实时跟踪,在工业生产中将得到更广泛的应用。