本文關(guān)鍵詞： 電火花排屑 極間流體仿真 模糊抬刀控制 抬刀參數(shù)優(yōu)化　出處：《哈爾濱工業(yè)大學(xué)》2016年碩士論文　論文類型：學(xué)位論文

【摘要】：隨著國(guó)際加工制造業(yè)地發(fā)展,機(jī)械產(chǎn)品變地小型化,精密化。電火花加工技術(shù)作為一種特種加工方法,以其非接觸,高精度的加工特點(diǎn)成為機(jī)械制造領(lǐng)域的重要方法之一。由于電火花加工過(guò)程處在一個(gè)相對(duì)密閉的環(huán)境中,加工產(chǎn)生的金屬?gòu)U屑難以排除,嚴(yán)重影響到正常加工的進(jìn)行。抬刀排屑作為一種獨(dú)立于電火花放電過(guò)程的排屑方式,通過(guò)介質(zhì)的流動(dòng)帶動(dòng)廢屑粒子從加工間隙中流出。為了深入研究抬刀動(dòng)作對(duì)排屑的影響,本文利用Ansys Fluent有限元仿真軟件建立了抬刀流體仿真模型,定性分析了煤油介質(zhì)的流動(dòng)形式;通過(guò)離散相技術(shù),定量分析了不同抬刀參數(shù)下極間廢屑粒子的排出量。為了滿足快速抬刀和微動(dòng)進(jìn)給的運(yùn)動(dòng)精度要求,加入了雙PID運(yùn)動(dòng)參數(shù)切換。在自主設(shè)計(jì)開發(fā)的數(shù)控平臺(tái)上進(jìn)行了不同抬刀參數(shù)下小孔加工工藝實(shí)驗(yàn),討論了抬刀參數(shù)對(duì)加工效果的影響。為了提高電火花放電穩(wěn)定性和加工效率,本文設(shè)計(jì)出模糊抬刀方案,將原本開環(huán)抬刀方式,通過(guò)加入模糊控制器設(shè)計(jì)成一個(gè)閉環(huán)伺服系統(tǒng)。在MATLAB中利用專用工具包設(shè)計(jì)搭建模糊抬刀控制器,利用前期抬刀流體仿真結(jié)果和開環(huán)抬刀實(shí)驗(yàn)結(jié)果總結(jié)抬刀規(guī)律,設(shè)計(jì)模糊數(shù)據(jù)庫(kù),完成控制器仿真。通過(guò)串口通信技術(shù),將實(shí)時(shí)采集到的極間電壓反饋給上位機(jī)。上位機(jī)通過(guò)運(yùn)算,將得到的電壓偏差值及偏差變化率作為控制器輸入,將抬刀高度和抬刀周期作為輸出,完成閉環(huán)伺服系統(tǒng)。利用C++語(yǔ)言編寫開環(huán)抬刀功能模塊和模糊抬刀功能模塊,并嵌入到數(shù)控系統(tǒng)中。最后,設(shè)計(jì)開環(huán)抬刀和閉環(huán)抬刀對(duì)比工藝實(shí)驗(yàn),驗(yàn)證模糊抬刀控制器的有效性。與傳統(tǒng)定時(shí)定速定高抬刀方法相比,模糊抬刀方案通過(guò)判斷電火花極間放電狀態(tài),實(shí)現(xiàn)抬刀參數(shù)實(shí)時(shí)優(yōu)化,提高了排屑效率,保證了極間放電的穩(wěn)定性,高效性。
[Abstract]:With the development of international manufacturing industry, mechanical products become miniaturized and refined. As a special processing method, EDM is non-contact. The characteristics of high precision machining have become one of the important methods in the field of mechanical manufacturing. Because the process of EDM is in a relatively closed environment, it is difficult to eliminate the metal scrap produced by machining. As a way of chip removal independent of the electric spark discharge process, the debris removal from the machining gap is driven by the flow of the medium. In order to study the influence of the lifting knife action on the chip removal, In this paper, Ansys Fluent finite element simulation software is used to establish the fluid simulation model of lifting tool, and the flow form of kerosene medium is qualitatively analyzed. In order to satisfy the requirement of moving precision of quick lifting knife and fretting feed, the quantity of debris particles discharged between poles under different lifting tool parameters was quantitatively analyzed. With the addition of double PID motion parameter switching, the machining process of small hole under different lifting parameters was carried out on the NC platform designed and developed by ourselves. In order to improve the stability of electric spark discharge and the machining efficiency, a fuzzy lifting tool scheme was designed, in which the original open-loop lifting method was used. A closed loop servo system is designed by adding fuzzy controller. In MATLAB, a special tool kit is used to design and build a fuzzy lifting tool controller. The rule of lifting knife is summarized by using the simulation results of pre-lifting fluid and the experimental results of open-loop lifting tool. The fuzzy database is designed and the controller simulation is completed. Through serial port communication technology, the voltage between poles collected in real time is fed back to the host computer. Through operation, the voltage deviation value and the variation rate of the voltage deviation obtained by the upper computer are taken as the input of the controller. The closed loop servo system is completed by taking the height and cycle of the lifting tool as the output. The function module of open loop lifting cutter and fuzzy lifting tool module are programmed by C language and embedded in the NC system. Finally, The experiment of contrasting open loop and closed loop lifting tool is designed to verify the effectiveness of fuzzy lifting tool controller. Compared with the traditional method of fixed speed and fixed height lifting tool, the fuzzy lifting tool scheme judges the discharge state between the electrodes of electric spark. The parameters of lifting tool are optimized in real time, the chip removal efficiency is improved, and the stability and efficiency of inter-pole discharge are ensured.
【學(xué)位授予單位】：哈爾濱工業(yè)大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2016
【分類號(hào)】：TG661

【參考文獻(xiàn)】

中國(guó)碩士學(xué)位論文全文數(shù)據(jù)庫(kù) 前1條

1 楊青照;電火花加工抬刀的自適應(yīng)控制研究[D];北京建筑大學(xué);2014年

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本文編號(hào)：1551071