【摘要】：智能手機(jī)行業(yè)正方興未艾。其中,金屬手機(jī)外殼以其優(yōu)異的質(zhì)感、耐磨損等優(yōu)點(diǎn)越來越受大眾的青睞,市場(chǎng)規(guī)模巨大。而目前智能手機(jī)的金屬外殼加工所使用的數(shù)控機(jī)床為傳統(tǒng)機(jī)床,并未考慮到同一工件大批量重復(fù)加工問題,仍然將大批量的加工任務(wù)當(dāng)作單件來生產(chǎn),導(dǎo)致次品率居高不下。為解決上述問題,本課題提出了迭代學(xué)習(xí)加工方法,使機(jī)床能夠利用先前的加工過程來優(yōu)化后續(xù)加工,以提高加工精度。迭代學(xué)習(xí)控制為核心控制算法,本課題將對(duì)其收斂性、穩(wěn)定性以及工程應(yīng)用過程中會(huì)出現(xiàn)的過沖現(xiàn)象進(jìn)行研究,并提出相應(yīng)解決方案。課題將驅(qū)動(dòng)器調(diào)節(jié)成速度閉環(huán)模式,而在控制器中完成位置環(huán)的搭建�；赿SPACE1103控制卡,課題設(shè)計(jì)了速度環(huán)路掃頻辨識(shí)實(shí)驗(yàn),得到了速度閉環(huán)的數(shù)學(xué)模型。工程實(shí)踐中往往將位置環(huán)的控制模式設(shè)為比例(Proportion)控制,為使得被控系統(tǒng)獲得良好的動(dòng)態(tài)特性,需要對(duì)控制參數(shù)P進(jìn)行適當(dāng)?shù)膬?yōu)化。課題中將采用迭代反饋整定方法進(jìn)行控制參數(shù)整定。迭代學(xué)習(xí)控制在應(yīng)用過程中往往會(huì)出現(xiàn)誤差先收斂后發(fā)散最終又收斂這一過沖現(xiàn)象。課題分別從時(shí)域和頻域兩個(gè)角度對(duì)這一現(xiàn)象進(jìn)行分析,得出結(jié)論:誤差頻譜中的高頻成分積累最終導(dǎo)致過沖現(xiàn)象。為解決這一問題,需要設(shè)計(jì)相關(guān)濾波器將誤差高頻成分過濾掉。而普通濾波器存在相位差,于是我們引入零相位濾波器來完成濾波。誤差的超前補(bǔ)償可以使誤差更快速地收斂到更小值。無論是零相位濾波還是誤差超前補(bǔ)償都是在兩次迭代運(yùn)行之間的離線狀態(tài)下完成的。具體的最優(yōu)超前補(bǔ)償步數(shù)與其對(duì)應(yīng)的最大截止頻率,需要依據(jù)算法設(shè)計(jì)相關(guān)的仿真實(shí)驗(yàn)來確定。根據(jù)過沖現(xiàn)象的成因分析和相關(guān)的濾波與補(bǔ)償機(jī)制,課題進(jìn)行了仿真實(shí)驗(yàn),得到了期望效果,誤差實(shí)現(xiàn)了單調(diào)收斂�；诶碚撏茖�(dǎo)與仿真實(shí)驗(yàn),課題設(shè)計(jì)了具體的數(shù)控機(jī)床實(shí)驗(yàn),誤差實(shí)現(xiàn)了單調(diào)收斂,最終誤差可以收斂到1μm以內(nèi),驗(yàn)證了零相位濾波與誤差超前補(bǔ)償?shù)男Ч�。并�?duì)迭代運(yùn)行過程中的誤差進(jìn)行了頻譜分析,從而可以直觀體現(xiàn)出零相位濾波的效果。
[Abstract]:The smartphone industry is in the ascendant. Among them, metal mobile phone shell is more and more popular because of its excellent texture, wear resistance and other advantages, and the market scale is huge. At present, the CNC machine tool used in the metal shell processing of smart phone is a traditional machine tool, which does not take into account the problem of mass repeated machining of the same workpiece, and still produces a large number of processing tasks as a single piece, resulting in a high rate of defective products. In order to solve the above problems, an iterative learning machining method is proposed in this paper, which enables the machine tool to optimize the subsequent machining by using the previous machining process in order to improve the machining accuracy. Iterative learning control is the core control algorithm. In this paper, the convergence, stability and overshoot phenomenon in the process of engineering application will be studied, and the corresponding solutions will be put forward. In this paper, the driver is adjusted to the speed closed loop mode, and the position loop is built in the controller. Based on dSPACE1103 control card, the frequency sweep identification experiment of speed loop is designed, and the mathematical model of speed closed loop is obtained. In engineering practice, the control mode of position loop is often set to proportional (Proportion) control. In order to obtain good dynamic characteristics of the controlled system, it is necessary to optimize the control parameter P. In this paper, the iterative feedback tuning method will be used to adjust the control parameters. In the application process of iterative learning control, the error converges first, then diverges, and then converges. This paper analyzes this phenomenon from the perspective of time domain and frequency domain, and draws the conclusion that the accumulation of high frequency components in the error spectrum eventually leads to overshoot. In order to solve this problem, it is necessary to design a correlation filter to filter out the high frequency components of the error. However, the common filter has phase difference, so we introduce zero-phase filter to complete the filtering. The advance compensation of the error can make the error converge to a smaller value more quickly. Both zero-phase filtering and error advance compensation are completed in the offline state between the two iterations. The optimal number of advance compensation steps and the corresponding maximum cutoff frequency need to be determined according to the simulation experiments designed by the algorithm. According to the cause analysis of overshoot phenomenon and the related filtering and compensation mechanism, the simulation experiment is carried out, and the expected effect is obtained, and the error realizes monotone convergence. Based on the theoretical derivation and simulation experiment, a concrete NC machine tool experiment is designed. The error converges monotonously, and the final error can converge to less than 1 渭 m. The effect of zero phase filtering and error advance compensation is verified. The spectrum analysis of the error in the iterative operation process is carried out, so that the effect of zero-phase filtering can be intuitively reflected.
【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】：2017
【分類號(hào)】：TP273

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