埋弧焊机数字化控制的研究

【作者】 杨绍辉；

【导师】 尹海；

【作者基本信息】 山东大学 ， 电力电子与电力传动， 2006， 硕士

【摘要】 本文介绍了埋弧焊的特点、发展历史、国内外的研究现状，分析了模拟电路控制系统和数字化控制系统的优缺点，指出数字化控制是逆变埋弧焊机控制的发展方向。对埋弧焊接过程和埋弧焊机控制系统进行分析，论述了变速送丝电弧控制系统的原理及影响因素，并且分析了焊接电弧的特性，为逆变埋弧焊机数字化控制系统的设计提供了理论依据。 针对传统埋弧焊机体积大、控制电路复杂、可靠性差等问题，在模拟控制系统的基础上做出改进，设计了基于单片机和FPGA的埋弧焊控制系统。由于送丝速度的均匀性直接影响到焊接过程的稳定性和焊缝的质量，良好的送丝速度控制系统是实现高质量焊接的前提。根据电弧的特性，设计了基于FPGA的模糊控制系统，用于送丝速度的调节，通过调节送丝速度保持电弧稳定。小车行走速度的调节也采用闭环控制，由数字PI产生PWM脉冲，驱动行车电机。针对埋弧焊接控制流程的特点，用VHDL语言编写了焊接程序，负责整个焊接过程的控制和各种保护功能的实现。 数字控制系统中的电磁干扰是难以避免的，因此在焊机控制电路和软件部分进行了可靠性与抗干扰设计，对可能影响焊机正常工作的干扰及其产生原因进行分析，并且在原理图设计、PCB制作以及程序编制的过程中采取了相应的抗干扰措施。 最后，对采用本控制系统的埋弧焊机进行初步实验，结果表明：本文所设计的埋弧焊机控制系统能够满足逆变埋弧自动焊的要求，具有电路简单，控制精度高，抗干扰能力强，操作方便，工作稳定可靠等特点，提高了焊机的综合性能及自动化程度。 本课题所研究的埋弧焊数字化控制系统，具有良好的输出特性并且可根据需求进行调整，很好地实现了非线性控制，可满足埋弧焊、手工焊等工艺要求。焊机的送丝速度和焊接速度采用数字控制算法调节，引弧、焊接、收弧过程由软件控制，电弧稳定、焊接质量好，而且还具有焊接数据存储和故障自诊断功能。更多还原

【Abstract】 The characteristic, history, actuality and foreground of submerged arc welding are introduced in the introduction part of this paper. It analyses the advantages and disadvantages of analog circuit control system and digital control system, point out that digital is the direction. It has an analysis on the process of submerged arc welding and control system, discusses the theory and reason of change-speed wire-feed system, analysis characteristic of the electrical arc, offer the theory for the design of digital control system of the submerged arc welding.According to the problems of too big body, complex control circuit and bad reliability, it design control system of microprocessor and FPGA, based on analog control system. Because the uniformity of wire-feed speed affects welding process to be stable and weld joint quality directly. Good control system of the wire-feed speed is precondition of realize high grade weld. This article design a fuzzy controller based on the VHDL language, according to the characteristic of electric arc specially. It is used to adjust the wire-feed speed, in order to make the electrical arc stable. The speed of the car adjusts by the closed-loop control. The PWM pulse drives the motor produced by digital PL To designed the welding program with the VHDL language, according to the characteristic of the flow with the submerged arc welding, to realize the entire control of welding process and all kinds of protection functions.Electromagnetism disturbances are inevitable in digital control system. Reliability and noise resistance designs are also covered in control circuit and software. The reasons of disturbance are analyzed, and some hardware and software measures are adopted in chart design, PCB making and program.Do an experiment on the control system of this paper, the experiment results indicates: It can meet the request of power source and process更多还原