新型双层复合管道微内窥检测系统设计

根据管道的具体结构特征,设计了适用于内管外径Φ180-220mm,外管内径大于Φ360mm的环形双层复合管道焊缝缺陷内窥检测系统。该系统由环形自转式运动机构,CCD摄像机以及基于DSP的运动控制卡和高分辨率的图像采集卡等组成。对系统的总体设计,关键技术分别进行了阐述。试验结果表明,所研制的基于视觉的双层管道微内窥检测系统方便,快捷,准确,满足实际工程需要。     

液力变矩器上盖与连续块MAG点固焊专机控制系统设计

针对液力变矩器连接块要求焊台定位精度高及生产上高效、高质的要求,从控制系统硬件和软件两方面进行了阐述,详细介绍了如何利用德国SIEMENS公司的SINUMERIK 810T CNC集成数控系统的优良性能,提高整个焊接专机系统的可靠性和自动化程度,并给出了系统结构框图和程序流程图。     

基于特征点提取和旋转不变技术的锁片基体视觉检测

针对锁片基体漏装检测中高速、柔性、准确的要求，采用视觉检测的方式进行检测。运用基于Harris探测算法的特征点提取并结合Zernike矩图像旋转不变技术，成功地解决了基体在图像中位置不固定的情况下检测耗时的问题，实现了锁片基体手工安装是否漏装的自动化视觉检测。实验证明，该方法具有实用性和高效性。     

基于DSP控制的十二相焊接电源主电路数字化触发

数字化焊接电源已经成为新型焊接屯潍的发展趋势，采用由数字信号处理器(DSP)作为控制核心对新型十二相晶闸管CO2气体保护焊接电源的主电路功率器件进行数字化触发。实验证明，通过DSP软件编程产生触发信号可靠稳定，实现了晶闸管的数字化触发。     

温度对高速电弧喷涂Fe-Al/Cr3C2涂层的影响

采用Fe—Al／Cr3C2粉芯丝材和高速电弧喷涂技术(HVAS)原位合成了复合涂层，对不同温度下涂层的组织和性能进行了研究。结果表明，随着温度的升高，涂层的耐冲蚀性能提高，涂层的耐蚀性能变化不大，涂层的结合强度提高，并且涂层表面氧化物膜增多，涂层组织颗粒变小，涂层结合处出现冶金结合。     

国产厚板大功率激光填丝焊Y形焊缝的焊接工艺性

大功率激光的高功率密度特征使其成为船用大厚度材料高效焊接最有前景的方法之一.试验完成了10mm和12mm国产船用材料高功率CO2激光填丝焊的工艺设计,分析了焊接过程的光致等离子体行为.结果表明,当功率在13kW以上时随着焊缝熔深的增加斜率明显变缓;对于焊透的焊缝,仅仅用熔宽和熔深不能充分表征焊接参数对焊缝截面的影响;试验建立了激光填丝焊Y形焊缝形态模型,将Y形焊缝抽象成上半部分为梯形,下半部分为长方形的组合图形;在激光功率和焊接速度保持不变的条件下,研究了送丝速度和焊缝间隙变化时焊缝截面形态的变化规律.     

高效焊接技术研究现状及进展

弧焊高效焊接技术主要以提高熔敷效率和焊接速度为目的.其中高熔敷效率焊接主要是在单位时间内熔化更多的焊接材料,代表工艺为T.I.M.E.焊接;高速焊接是在提高焊接速度的同时提高焊接电流,以维持焊接热输入大体上保持不变,代表工艺以多丝弧焊技术为主.此外,高效焊接技术还包括其它焊接方法,都可以大大提高焊接效率,主要有激光复合焊,A-TIG焊等.文中主要介绍了这几种典型的弧焊高效焊接技术的研究现状及其进展.     

铝合金P-MIG焊接电流对电弧形态的影响

通过对铝镁合金进行脉冲氩弧焊(P-MIG),在相同平均电流和平均电压工作条件下,调节不同峰值电流和基值电流,获得了不同的电弧形态.峰值电流对电弧形态有着重要的影响,而基值电流基本没有影响.基值电流是维持电弧燃烧的参数,在基值时间阶段,必须给定一个足够大的基值电流才能维持电弧的稳定燃烧.文中定义了电弧形态的表征值,针对电流对电弧形态表征值的影响进行了分析.峰值电流是决定电弧温度和脉冲能量的重要参数,铝合金电弧充分燃烧时电弧长度、电弧宽度和电弧纵向截面面积随着峰值电流增加而增加.

Abstract：

Under the same average welding current and welding voltage, by regulating the different based current and peak current, the Al-Mg alloy was welded with Al-Mg filler wire. The photos of welding arc were obtained by using high-speed video photography.Peak current has great influence on the shape and characteristics of the arc. With increasing the peak cunent value, rotated arc appears and pulsed rotated metal transfer behavior occurs. Based current has little influence on the arc shape. Base current is the important parameter for keeping arc burning. At pulse off time, it must be given base current value which is large enough to keep the arc burning stably. In this study, the arc shape is defined by arc length, arc width and arc portrait cross-section area, which will be influenced by the weld current. Peak current is important parameter of arc temperature and pulse energy. The study shows that when the arc is burning at pulse on time, the arc length, arc width and arc pomait cross-section area increase with raising peak current.     

基于卡尔曼滤波的焊缝偏差实时最优估计

建立了基于卡尔曼滤波的焊缝偏差实时最优估计算法.以焊缝中心位置为特征矢量,建立焊缝位置检测的状态方程和测量方程,并依据最小均方差原则建立了卡尔曼滤波最优估计的递推算法.测量噪声协方差由传感器测量误差的统计值得到,假定过程噪声是由于加速度变化引入,通过两点法确定焊缝中心位置的初值.在焊接过程中,应用卡尔曼滤波消除噪声干扰,实现焊缝位置的实时精确预测.计算机仿真和试验结果表明,焊缝偏差信号经过卡尔曼滤波处理后,消除了偶然因素和随机噪声的影响,提高了跟踪精度以及系统工作的稳定性,适合实际工程应用.

Abstract：

The optimal estimation algorithm for real-time welding deviation based on Kalman filtering is presented. The state equation and measurement equation for detecting the weld position is established, and the optimal estimation of the Kalman filtering recursive algorithm also is established according to the principle of minimum mean square error. Measurement noise covariance is obtained from the statistical value of measurement error, and after the process noise is supposed to derive from the changes in acceleration, the initial values of the welding center position are determined by the twopoint method. During the welding process, the welding position is accurately predicted while the noise interference is eliminated by Kalman filtering. The computer simulation and experiment results show that the weld deviation signal processed by the Kalman filtering can eliminate the disturbance of causal factors and random noise,improve the tracking precision and the stability of system, and be suitable for the practical engineering applications.     

脉冲熔化极气体保护焊熔滴过渡电信号特征及建模

脉冲熔化极气体保护焊(GMAW-P)熔滴过渡形式对焊接质量有着重要的影响,同时脉冲参数是影响GMAW-P熔滴过渡行为的主要参数.利用高速数字摄像技术,记录熔滴过渡过程,同时采集焊接过程的电流、电压信号,并将各个信息传输到PC机中,实现数据的保存.综合分析熔滴过渡图片与对应的电信号的关系,提取了GMAW-P熔滴过渡过程特征电信号.通过统计分析建立了GMAW-P熔滴过渡逻辑回归模型.结果表明,此模型预测熔滴过渡的正确率达93%,为实现一脉一滴最佳脉冲熔滴过渡形式闭环控制开辟了新的途径.

Abstract：

Metal droplet transfer mode which is influenced by the pulse parameters such as pulse current ( I_p ) , pulse time ( t_p ) , base current ( I_b ) and pulse frequency (f) has play an important role in the weld quality. An experimental system based on the Lab VIEW virtual instrument and high speed photography technology was developed to sample the transient electrical parameters and record the images of droplet transfer process simultaneously. A transition voltage U_(dd) in the pulse voltage drop edge of electrical waveform was discovered according to analysis of synchronous electric and image signals. The relationship between the metal transfer mode and the slope of the transition voltage was proposed. The result of experiments shows that the model can be used in closed-loop controlling of one droplet per pulse transfer mode and also can help for optimizing the welding parameters.