Research on the properties of MAG welded joint of X65 pipeline steel

With the worldwide pipeline construction boom, the pipeline welding technology has rapidly developed. Considering the needs of some projects, many tests of mechanical properties of X65 pipeline steel metal active-gus （MAG） welded joint have been carried out, and so do the analysis of metallographic structure characteristics and the impact fracture appearance of joint. The results show that, using MAG welding, the test data of mechanical properties of their girth welded joint are in conformity with the relevant technical standards （ API1104 ）. MAG welding with COz protection has the characteristics of low hydrogen, energy-saving and environmental protection. Therefore, it should be noted to develop the welding materials and equipments vigorously for this welding method.     

基于无差拍电压空间矢量控制的SVG仿真研究

提出一种静止无功发生器无功补偿的新方法——基于无差拍电压空间矢量控制.该方法通过瞬时无功功率理论的无功电流检测法实时检测无功电流,提高了系统响应速度.针对直接电流控制开关频率过高的不足,引入了电压空间矢量技术,分析了电压空间矢量在静止无功发生器中的应用原理.为了消除采样及计算等带来的延时,引入了无差拍控制技术.最后通过Matlab对控制方案做了系统仿真,将无差拍与电压空间矢量SVPWM相结合,分析实时的仿真波形,仿真结果验证了所选控制方案的有效性和可行性.     

机器人弧焊成形系统中离线自动编程

目前的机器人离线编程系统大多采用图形示教方式建立机器人运动路径,然而这种编程方式对于复杂路径来说工作量仍是相当大的,而且对于路径规划直接计算得出的机器人位置数据及弧焊操作指令无法方便地形成机器人程序(relative job,JOB).文中以弧焊机器人为对象进行了离线自动编程的研究.利用MOTOMAN机器人的相对JOB数据交换格式,实现了MOTOMAN机器人相对JOB的离线自动编程,自动生成机器人程序.离线自动编程模块通过ODBC接口从弧焊成形系统中相应的规划数据库取得指令代码及数据,充分发挥数据库的优势,有利于离线编程系统的扩展.结果表明,研究的离线编程运行稳定,机器人动作连贯,焊接路径与设计吻合.     

抗积分饱和控制在无刷直流电动机中的应用与研究

正无刷直流电动机调速系统是一个多变量、非线性系统,建立了无刷直流电动机的数学模型,并分析了转矩脉动产生的原因和防止积分饱和的方法,就传统PI控制器和PWM调制方式下的积分饱和问题,把积分钳位式Anti-windup控制方式应用到无刷直流电动机的控制中,设计了抗积分饱和速度调节器。仿真结果表明,此方法可以有效限制积分饱和现象,提高系统的控制性能。无刷直流电动机是随着高性能永磁材料和自动控制技术的发展,特别是大功率半导体器件的快速发展才发展起来的新型电动机。其转子采用永磁材料励磁,具有体积小、重量轻、结构简单且易于控制等优点,已在航空航天、仪器     

微压力液位变送器在二次供水中的应用

通过实验论证了微压力液位变送器在水箱液位检测中的可行性,并分析对比了这两种类型液位变送器的优缺点及注意事项,为微压力液位变送器替代投入式液位变送器在二次供水中的应用提供了依据。     

Research and engineering application of the arc welding pulsed controller technology

The tenacity of heat-affected zone （HAZ） will decline and the size of grains will increase, because of the overheating on HAZ when submerged are welding （SAW） is ased to thick plate with high heat input. The shaping will worsen when SAW is used to thin plate with high current at high speed. A new SAW technology, the pulsed direct current （DC） automatic SAW, will be put forward in this paper in order to overcome the above shortcomings. And a pulsed controller with micro-controller unit （MCU） as the core, nixie tube （NT） and keyboard as the man-machine conversation interface is developed. The main functions of the pulsed controller include the output of pulsed welding current and the working with twinwire. The research has widely prospects in application with significant meanings in theory and practical engineering.     

永磁同步直线电动机的模型辨识

将MATLAB与DSP结合起来,实现在MATLAB/Simulink中搭建算法,编译生成DSP代码,控制直线电动机,从而获得电机的频率特性数据。并利用由幅频特性推导传递函数的原理,编写M文件处理数据,获得直线电动机的拟合状态方程和传递函数。通过对比电机、拟合状态方程和传递函数的频率响应,得到传递函数,用于直线电动机的控制设计中。     

Research and engineering application of the arc welding pulsed controller technology

0IntroductionSubmerged arc welding(SAW)is a welding processwhere the arc burns under flux[1].Automatic SAW hasbeen widely put into practice in the fields of ship-building,energy industry and mechanical engineering for its high ef-ficiency,good quality,flexibility of adjustment and fairlynice working condition.In a word,SAW can carry outwelding of high quality with high current at high speed.High heat input is usually applied for more depositedmetal when SAWis used to weld thick plate.In …     

不平衡系统下无功补偿的策略研究

本系统设计的是以三电平空间矢量控制方案建立调制数学模型并分析控制过程,以瞬时无功理论为基础对无功量进行提取,又讨论了负载在不平衡时的补偿,通过基于d-q坐标系的双序同步控制SVG的策略,分离出三相不对称的正负序分量,采用对正序和负序同步控制器分别对SVG的输出进行正序和负序分量闭环反馈控制,最终实现对无功功率的实时补偿和提高电网的功率因数,通过仿真验证了该理论的正确性,并且通过实验对其中阻感负载情况下的无功分量进行实时补偿,根据提取的无功量通过空间矢量调制,补偿到电网中使功率因数得到显著提升。     

Study on DC welding parameters of Al-alloy shaping based on arc-welding robot

The Al-alloy arc-welding shaping system based on arc-welding robot is established, and the Al-alloy shaping manufacture is realized with the DC （direct current） gas metal arc welding （GMAW）. The research indicates that the metal transfer type of DC GMA W, heat input and the initial temperature of the workpiece greatly affect the Al-alloy shaping based on arc welding robot. On the penetration, the weld width and the reinforcement, the influence of welding parameters is analyzed by generalized regression neural network （GRNN） fitting.