低飞溅脉冲GMAW焊机波形数字控制策略的研究

发布时间：2018-01-13 01:14

本文关键词：低飞溅脉冲GMAW焊机波形数字控制策略的研究　出处：《华南理工大学》2015年硕士论文　论文类型：学位论文

更多相关文章： 脉冲GMAW焊 熔滴过渡 飞溅 中值控制

【摘要】：脉冲GMAW焊具有高效节能、控制方式灵活、适应性强等特点,可在较大的电流调节范围内实现喷射过渡,焊缝成形较美观,在制造业中得到广泛的应用。其不足之处在于,熔滴的复杂性与随机性会使过渡状态和形式难以稳定,导致无法有效地控制热输入量,在焊接过程中可能会产生不同过渡状态,形成尺寸不均匀的熔滴或产生飞溅,从而影响焊缝成形质量。因此,需通过有效的控制方式使熔滴过渡尽可能稳定在有利于焊缝成形的状态,进一步提高脉冲GMAW焊的焊接成形质量。在国家自然科学基金项目(资助号：E51375173)的资助下,本文研究了一种全数字脉冲GMAW焊机,并采用中值波形控制策略实现了对焊接过程热输入量的精细化控制。研发样机具有普通脉冲模式、中中值脉冲模式、后中值脉冲模式、恒压模式等多种焊接模式。论文首先阐述了课题背景,分析了脉冲GMAW焊机技术的现状及发展趋势；在此基础上,讨论了熔滴过渡的状态和形式及其对焊接过程的影响；分析了工艺参数对焊缝成形的具体影响及飞溅产生的原因。其次,根据脉冲GMAW焊接的工艺特点及要求,完成了以Cortex-M4内核ARM处理器为核心的样机开发；包括全桥逆变主电路、控制系统电路、电源模块、芯片最小系统等硬件设计及基于RTX实时操作系统的主控制板和数字面板的软件设计。最后,利用示波器、三相调压器、机械手等设备完成大量的工艺实验,对比及分析了不同模式下的波形控制方法及其焊缝成形效果,尤其是飞溅程度,并对控制策略的有效性进行了分析。结果表明,中值控制策略下的焊缝成形明显优于普通脉冲模式,前者的熔滴过渡更规律、稳定,熔宽均匀、熔合良好、飞溅明显减少。焊缝成形由好至坏依次为：后中值脉冲模式、中中值脉冲模式、普通脉冲模式、恒压模式。
[Abstract]:Pulse GMAW welding has the characteristics of high efficiency and energy saving, flexible control mode and strong adaptability. It can realize spray transition in a large range of current regulation, and the weld formation is more beautiful. It is widely used in manufacturing industry. Its disadvantage is that the complexity and randomness of droplet will make it difficult to stabilize the transition state and form, resulting in the inability to effectively control the heat input. In the welding process, different transition states may occur, resulting in uneven size droplets or spatter, which will affect the quality of weld formation. It is necessary to make the droplet transfer as stable as possible in favor of weld formation through effective control. In order to improve the welding quality of pulsed GMAW welding, a digital pulsed GMAW welding machine is studied in this paper, with the support of the National Natural Science Foundation of China (Grant No.: E51375173). The control strategy of median waveform is used to control the heat input of welding process. The prototype has three modes: normal pulse mode, middle median pulse mode and posterior median pulse mode. At first, the paper describes the background of the subject, and analyzes the current situation and development trend of pulsed GMAW welding machine technology. On this basis, the state and form of droplet transfer and its influence on welding process are discussed. The influence of process parameters on weld formation and the cause of spatter are analyzed. Secondly, according to the characteristics and requirements of pulsed GMAW welding process. The prototype development based on Cortex-M4 kernel ARM processor is completed. Including full-bridge inverter main circuit, control system circuit, power module, chip minimum system hardware design and RTX real-time operating system based on the main control board and digital panel software design. Finally, using oscilloscope. Three-phase voltage regulator, manipulator and other equipment completed a large number of process experiments, compared and analyzed in different modes of waveform control methods and weld formation effect, especially the degree of spatter. The effectiveness of the control strategy is analyzed. The results show that the weld formation under the median control strategy is obviously superior to the conventional pulse mode, the former is more regular, stable, uniform melting width and good fusion. The order of weld forming from good to bad is: posterior median pulse mode, middle median pulse mode, common pulse mode, constant voltage mode.
【学位授予单位】：华南理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TG434.5

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