【作者】 朱继东；

【导师】 陈坚； 周志江；

【作者基本信息】 上海交通大学 ， 控制工程， 2009， 硕士

【摘要】 目前,我国拥有自主知识产权的国产辙叉闪光对接焊机尚属空白,现场生产的辙叉焊接主要依靠引进国外的焊接设备或技术。本课题在研究了国外现行的主流闪光焊接装备的基础上,综合利用和结合了我国现有的技术与成果,研制了第一台具有自主知识产权的辙叉闪光对接焊机。这一成果摆脱了辙叉闪光焊接依赖进口设备的局面,实现了辙叉焊接装备国产化,对于节约外汇,提高我国焊接设备自动化水平有重要意义。在研制中,依照闪光焊工艺参数的特点,参考大量实际生产经验,确定了合理的闪光焊工艺参数。按照闪光焊各个闪光阶段的工艺要求,建立了闪光速度控制的模型。闪光焊机是一个多变量、非线性、时变、随机干扰较强的系统,且无法确定准确的数学模型。采用经典的PID控制,动态调节时间长,超调量大,而且PID参数难以在线整定,影响闪光控制效果。针对经典PID控制器存在的问题,引入了模糊控制的控制策略,模糊控制器是一种近年来发展起来的新型控制器,其优点是不要求掌握受控对象的精确数学模型,将模糊控制和PID控制两者结合起来,扬长避短,既具有模糊控制灵活而适应性强的优点,又具有PID控制精度高的特点。采用模糊PID控制策略来调整闪光速度,达到控制闪光电流的目的。该控制器结构简单,易于实现,系统跟踪性能好,超调量小,在实际应用中效果较理想。以闪光焊接工艺控制模型为基础,开发了一套以模糊PID控制器为基础的计算机控制系统。控制系统由工控机、PLC、数据采集系统等部分组成。PLC负责控制焊接的过程控制,工控机负责实时数据的采集、显示和储存。以Rockwell公司的PLC为控制核心,以Fuzzy-PID参数自整定控制策略的控制系统,实现了闪光焊全过程自动控制,在连续闪光焊阶段,将电流控制在限制之内,超调部分也不超过10%。采用该控制系统后,提高了闪光焊设备的效率,自动化程度更高,更加有利于焊接出高质量的焊头,实现了较好的经济技术指标。更多还原

【Abstract】 Now,the flash butt welder of frog which hold self-owned intellectual property has not been even put into operation in China,frog welding mainly depends on the technology and equipment from abroad. In this dissertation,we use existing technology and production and develop the first flash butt welder which hold self-owned intellectual property in China,based on researching on flash welding equipment abroad. This technical achievement breaks away from the situation that we depends on import equipment to weld frog, realizes localization of frog welding equipment. It is importance to improve our automation level of welding equipment and save foreign exchange.In the dissertation,we definite the rational technological parameter of flash welding according to the feature of parameter and many of production experience. We build the model of flash speed control according to the each flash stage of flash welding. Flash welding is a kind of system with multivariable, nonlinear, time-variation and strong random disturbance,and it can not fix on its accurate mathematical model. Traditional PID control have the features of long dynamic regulation time and high overshoot,moreover its PID parameters can hardly set online,and all this will effect the quality of welding products. So, Fuzzy control is drown into use to resolve the fault of traditional PID. Fuzzy controller is a sort of late model controller developed in last several years, its is a kind of precision mathematical model which don’t require control controlled plant, contrarily, it organize and control decision table according to manual control regulation,and then determine controlled variable by control decision table. The method that band fuzzy control and PID control together not only have the merit of flexible and strong adaptable fuzzy control, but also have the feature of high precision PID control.We adjust flash speed by using Fuzzy-PID control strategy to control flash current. This controller is of simple structure, easy to achieve, better trace performance, less overshoot and good effects in practical application. On the basis of the mathematic model of controlling process, we design a set of computer control system for Fuzzy-PID controller by superior computer, PLC, data acquisition system and other units. The PLC take charge of process control of welding, computer take charge of data to collect, display and store. By taking PLC made by Rockwell Corp. as main unit and Fuzzy-PID controller as control strategy, the automatic control function of flash welding is realized. In the sequence-flashing stage, this controller is managing to control the current into setting range, and overshoot decline10%. After using this control system, the welder is of efficiency to weld, good to get high-quality welding head, and better economic and technical indicators is achieved.更多还原