【作者】 石玗；

【导师】 樊丁；

【作者基本信息】 兰州理工大学 ， 材料加工工程， 2005， 博士

【摘要】 近年来,随着汽车、列车等运输装置向轻量化发展,铝合金焊接结构生产的自动化、智能化和信息化成为日益重要的研究课题,本文针对其中的一些关键问题进行了深入研究。 弧焊机器人用数控焊接变位机的研制对弧焊机器人柔性加工单元(WFMC)的设计具有重要的意义。本文设计了基于模糊规则的智能双模协调控制器,即采用PID控制器和模糊控制器的加权合成算法,控制过程中模糊控制器和PID控制器同时输出控制量,当控制误差较大时模糊控制器的输出权重较大,而当控制误差较小时PID控制器的输出权重较大,有效避免了变结构控制器切换过程中的震荡,实现了焊接变位机的高精度位置控制。论文对实时控制软件的结构设计和实时性要求进行了详细的理论分析,提出了基于DOS系统下的高精度数控焊接变位机多任务实时控制软件的设计与实现方法。利用工业控制计算机和单片机实现了示教盒、操纵杆和计算机键盘等三种示教装置,同时设计了一套包括程序控制指令、轨迹描述指令和I/O通讯指令的数控焊接变位机控制指令系统。进行了多种工件的焊接试验,试验表明该控制系统工作可靠,效果良好。 由于铝合金焊接过程中存在很多不确定因素,实时的检测和控制熔池动态过程是保证焊接质量的一种重要方法。本文建立了铝合金熔池图像检测视觉系统。通过窄带滤光结构,有效地克服了弧光干扰,并获得了比较清晰的铝合金MIG焊熔池图像。分析了铝合金MIG焊熔池图像特征,并提出了相应的熔池图像处理算法。针对传统图像处理算法的不足,提出利用形态学方法去除图像信号中的噪声、阴极雾化区等影响熔池特征提取的部分,获得了满意的熔池边缘图像,可以对熔池形状信息进行动态检测。在此基础上,设计了阶跃响应试验,利用曲线拟合法对基值电流、送丝速度、脉冲电流占空比、焊接速度与熔宽的模型分别进行了辨识,分析了它们对熔宽的影响规律,为铝合金脉冲MIG焊过程控制提供了理论依据。设计了适于铝合金脉冲MIG焊过程控制的模糊—专家控制系统,利用此系统成功实现了铝合金机器人脉冲MIG焊熔宽实时控制,通过控制焊接脉冲电流占空比和送丝速度获得理想的焊缝宽度。实验表明,利用建立的熔池图像检测和控制系统,通过提出的图像处理和控制算法,能够实现在铝合金MIG焊过程中实时、精确的控制熔池变化并获得一致的熔宽。 利用嵌入式网关结合单片机控制系统实现了数字电焊机的以太网接入,可以使作为现场生产单元的电焊机与目前基于以太网和TCP/IP协议的企业信息系统无缝集成。同时设计了网络电焊机管理系统,并利用SQL SERVER构建了基于web的焊接规范数据库和焊接生产过程监测数据库。整个系统可以实现焊接规范参数数据库的维护、电焊机参数远程监控和焊接规范的远程设置与网络化管理。更多还原

【Abstract】 In resent years, lightweight has become a core problem for development of means of transportation such as automobile and high speed train, so more and more aluminum alloy welding structures have been widely applied to vehicle. In order to adapt to this tend, some key problems of automatized, intelligent and information welding production for aluminum alloy structure were studied in this paper.Development of numerically controlled (NC) robotic positioner is of vital importance to the design of welding flexible manufacturing center (WFMC) of arc-welding robot. The control system has taken 2-aixs servo motor control card as its core and used a two-mode controller that based on Fuzz and PID control method as its position controller. In the tow-mode controller, the outputs of Fuzz and PID acted on object at the same time, but weights of the Fuzz and PID were differing from value of error. This structure avoided concussion effectively when from one controller switch to other controller. The tow-mode controller has realized precise control over position of welding positioner. This paper has made a detail theoretical analysis of the constitution design and real-time controlled software and brought up the design and fulfillment method of multi-task real-time control software of high precisely and numerically controlled welding positioner. Three teaching devices which are teaching-box, joy-stick and computer keyboard are fulfilled with industry control computer and single-chip, and a set of control command system of NC welding positioner is also designed, including program command, track description command and I/O communicating command. Good results obtained in practice.Real-time sensing and control of weld pool dynamics are important techniques to ensure expected weld quality because there are many uncertain effects especially during aluminum alloy welding process. A vision sensing system for taking and processing the image of MIG welding pool of aluminum alloy has been setup in this paper. Clear images of the MIG welding pool are obtained by using the technology of narrow band filter, which used to overcome the influence of strong arc light. The aluminum alloy’s characteristic of the MIG welding pool is analyzed. A corresponding image-processing algorithm has been developed to acquire characteristic parameters of the weld pool in real time. In order to overcome the disadvantages of traditional welding pool image processing method, the morphological operators is used to process the aluminum alloy MIG welding pool. This method can effectively wipe off noise and ’cathode pulverization’ area in image. The morphological operator is used to process the aluminum alloy MIG welding pool. By using the result of the image processing, a simulation model of the welding system is prepared to make a digital controller. The welding pool width model of dynamic process in Aluminum Alloy pulsed MIG welding is identified by least square method. The input of the model is welding wire speed, base current, welding speed and pulse duty ratio respectively, and the output is beam width of welding pool. The order of these factors influence on welding pool width is analyzed. Based on Fuzzy controller and expert system (ES), real-time control of dynamic weld pool for topside weld width during robotic-pulsedMIG process has been realized in this study. Welding pulse duty ratio and wire-feed speed are controlled to get the desired bead width. The experiments show that the real-time and precision requirements for detecting and control of weld pool changes and bead width of aluminum alloy pulsed MIG welding process could be satisfied by developed image processing and control algorithm on the established systems.With the development of technology of Ethernet, how to apply it to industry filed is a very important problem. The author utilize the embedded gateway combining with MCU controlling system to fulfill the welding machine connection with Ethernet, which could integrate the welding machine with company information system based on Ethernet and TCP/IP completely, and which could make possible of remote management during the welding production and remote diagnosis of welding machine faults via Ethernet. And the author, utilizing SQL SERVER software, design the Net-welding machine managing system, construct the welding standard database and welding process supervision database based on web. The whole system could fulfill the maintenance of welding criterion database, the remote supervision of welding machine parameters and the remote setup of welding criterion and management based on Network..更多还原