【作者】 宋东风；

【导师】 胡绳荪；

【作者基本信息】 天津大学 ， 材料加工工程， 2006， 硕士

【摘要】 随着科学技术的发展,MIG焊在全位置自动焊接方面的应用越来越普遍。但是,由于焊接结构的限制,在焊接过程中焊枪喷嘴和工件表面的距离必然会发生变化,从而引起弧长及焊接过程的不稳定。在MIG焊接过程中,当焊枪喷嘴与工件表面的距离发生变化时,如何保证焊接弧长的稳定是焊接自动化领域研究的重要课题之一。本文分析了MIG焊接工艺参数对焊接过程及焊接质量的影响,并基于此提出了采用变速送丝配合缓降特性焊接电源的焊接弧长控制策略。鉴于焊接弧长控制系统通常为复杂的非线性系统,本文将模糊控制理论引入弧长控制过程中。本文以电弧电压为控制量,送丝速度为被控制量,采用MATLAB软件实现了双输入、单输出弧长模糊控制器的设计,并通过仿真对模糊控制中的比例因子和量化因子进行了优化。仿真结果表明,优化后的模糊控制器具有良好的响应特性和稳态精度。本文以MSP430F149单片机和TMS320LF2407型DSP为主控芯片,完成了数字化MIG焊弧长模糊控制系统的硬件电路和软件的设计。焊接试验表明,本文所研制的数字化软、硬件系统工作可靠;弧长模糊控制系统的数学模型正确。该系统能够在焊枪喷嘴和工件表面的距离发生变化时,保持电弧弧长一定,从而保证焊接过程的稳定。更多还原

【Abstract】 With the development of welding technology, MIG welding has been increasingly used in automatic welding of all position. However, during the welding, the distance between the welding torch muzzle and the surface of the work piece has to change because of the confine of welded structure, which will cause instabilities of the welding arc and the welding process. To keep the stability of welding arc is an important task in welding automation field, when the distance between the welding torch muzzle and the surface of the work piece changes.This paper analyzes how welding conditions tamper with welding process and welding quality, and the united control strategy of arc length control, by using changeable wire speed and drop-characteristic welding power source, is presented based on this analysis. The fuzzy control theory is inducted to the control as the control system is a complicated nonlinear one.The fuzzy arc length controller is established with arc voltage as the input and wire speed as the output, based on the MATLAB software. Optimizing of the controller’s parameters is proceeded based on simulations, and the results indicate a good response characteristic and high precision. The hardware and software design of the control system is completed, taking the MSP430F149 MCU and TMS320LF2407 DSP as chief controllers.The welding experiments indicate the accuracy of the mathematics model of the designed fuzzy control system and the stable work condition of the digital control system. Even when the distance between the welding torch muzzle and the surface of the work piece changes, this control system will keep the stability of arc length, so as to achieve a stable welding process.更多还原