钨极氩弧焊弧长自动控制的研究

发布时间：2018-04-29 06:13

本文选题：TIG焊 + 质量控制保证　；参考：《西南交通大学》2017年硕士论文

【摘要】：21世纪以来,焊接产品质量控制与保证产品质量已成为焊接制造技术的焦点问题之一,而新兴的各种复合型TIG焊接工艺不但保留一般TIG焊的共同优点,同时突破传统TIG焊的局限,兼具高质量和大焊速,应用广泛。TIG焊接过程中电弧长度的稳定性直接影响焊接质量,因此在精密工件的焊接时需要引入TIG弧长自动控制系统以保证焊接质量。本文在调研主流TIG弧长自动控制技术和设计方案的基础上,分析了现有TIG弧长控制系统的缺点:功能单一、结构复杂、自动化程度低、成本较高等,提出了以数字PID为控制策略的新型交直流及脉冲TIG弧长自动控制系统:以弧压为弧长信号,采用步进电机细分驱动以提高控制精度,以单片机为控制核心增强系统的柔性。在系统硬件电路设计中考虑了系统对高频引弧、高压脉冲引弧和高压脉冲稳弧的适应性和对交直流的兼容性,设计了信号选择电路、弧压采集处理电路、单片机控制系统、液晶显示电路、细分驱动电路、定位检测电路等,并对焊枪调整机构的步进电机及行走机构进行了设计与选型。结合所设计的系统硬件,以c语言按模块化编写AD转化、去极值均值滤波信号处理、控制算法、液晶显示、控制信号生成等功能子程序,实现弧长自动控制的基本功能。搭建了 TIG焊接弧长控制试验平台,设计了弧长跟踪控制试验,通过试凑法调整获得了系统参数,并优化了弧长控制性能。试验表明:将带死区的变速积分PID控制算法应用于交直流钨极氩弧焊弧长跟踪,能提高系统的动态性能和控制精度,更好满足自动化焊接的弧长控制需求。
[Abstract]:Since the 21st century, the quality control and quality assurance of welding products has become one of the focus problems in welding manufacturing technology. However, the emerging hybrid TIG welding processes not only retain the common advantages of general TIG welding, but also improve the quality of welding products. At the same time, it breaks through the limitation of traditional TIG welding and has both high quality and large welding speed. The stability of arc length in wide application of .TIG welding process directly affects the welding quality. So it is necessary to introduce TIG arc length control system to ensure welding quality. Based on the investigation of mainstream TIG arc length control technology and design scheme, this paper analyzes the shortcomings of the existing TIG arc length control system: single function, complex structure, low automation, high cost, etc. A new type of AC / DC and pulse TIG arc length automatic control system based on digital PID is proposed. The arc voltage is taken as the arc length signal, the step motor is subdivided to improve the control precision, and the single chip microcomputer is used as the control core to enhance the flexibility of the system. In the system hardware circuit design, the adaptability of the system to high frequency arc starting, high voltage pulse starting arc and high voltage pulse stabilizing arc and compatibility to AC / DC are considered. The signal selection circuit, arc voltage acquisition and processing circuit, single chip microcomputer control system are designed. Liquid crystal display circuit, subdivision drive circuit, position detection circuit and so on. The step motor and walking mechanism of welding torch adjusting mechanism are designed and selected. Combined with the hardware of the system, the basic function of automatic arc length control is realized by using c language to program AD transform, deextremum mean filter signal processing, control algorithm, liquid crystal display, control signal generation and so on. The TIG welding arc length control test platform was built, and the arc length tracking control test was designed. The system parameters were obtained by trial and error method, and the arc length control performance was optimized. The test results show that the application of variable speed integral PID control algorithm with dead zone in arc length tracking of AC / DC TIG welding can improve the dynamic performance and control accuracy of the system and better meet the requirements of arc length control for automatic welding.
【学位授予单位】：西南交通大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TG444.74

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