【摘要】：切削作為一種主要的金屬加工方式，廣泛地存在現(xiàn)代制造業(yè)中。切削加工中的振動，尤其是顫振是制約其加工效率與精度的主要因素之一。為了提高加工質(zhì)量與生產(chǎn)效率，有必要對切削振動實現(xiàn)有效地控制。 本文將以車削和銑削過程為研究對象，建立一個具有時滯特性的系統(tǒng)加工動力學(xué)方程。由于切削動力學(xué)方程是具有時滯的微分方程，具有無窮多個特征根,全部求解其特征根具有非常大的難度。本文首先使用特征根方法討論傳統(tǒng)的單時滯反饋控在車削過程中的穩(wěn)定域問題；在此基礎(chǔ)上，對單時滯反饋控制進(jìn)行了時域仿真，指出了其優(yōu)點和不足。然后利用離散法，將車削動力學(xué)方程等效為一個標(biāo)準(zhǔn)的離散狀態(tài)空間方程，基于線性二次型最優(yōu)控制原理設(shè)計多時滯控制器，并對控制效果進(jìn)行數(shù)值模擬驗證。結(jié)果證明文中提出的時滯主動控制器能有效提高車削過程的穩(wěn)定性，擴大穩(wěn)定切削區(qū)域。同時討論了控制時滯對控制效率及控制力的影響。 相比于車削過程，銑削過程的復(fù)雜性不僅在于系統(tǒng)中時滯的存在，還在于由于銑削過程中刀齒旋轉(zhuǎn)切削運動的周期性，這導(dǎo)致銑削動力學(xué)方程中的系數(shù)呈周期性變化。本文首先上使用半離散法討論了狀態(tài)時滯控制在銑削過程中的可行性；然后將銑削動力學(xué)方程的時變周期系數(shù)在一個周期內(nèi)進(jìn)行平均化處理，使之成為定常系數(shù)的時滯微分方程，基于此設(shè)計了雙時滯主動控制器。隨后討論了雙時滯在銑削振動控制中對控制效率的影響，并探討了時滯不穩(wěn)定區(qū)域與銑削系統(tǒng)分叉特性之間的聯(lián)系。同時發(fā)現(xiàn)銑削系統(tǒng)在特定轉(zhuǎn)速下發(fā)生倍周期分叉時，，時滯控制器將會失效。為了解決這一問題，文中將最低控制目標(biāo)調(diào)整為定值，在一定程度上解決了時滯控制器失效的問題。
[Abstract]:As one of the main metal working methods, cutting is widely used in modern manufacturing industry. Vibration, especially flutter, is one of the main factors that restrict the machining efficiency and precision. In order to improve machining quality and production efficiency, it is necessary to control cutting vibration effectively. In this paper, taking turning and milling process as the research object, a system machining dynamics equation with time-delay characteristic is established. Since the cutting dynamics equation is a differential equation with time-delay and has infinitely many characteristic roots, it is very difficult to solve all the characteristic roots. In this paper, the characteristic root method is used to discuss the stability domain of the traditional feedback control with single time delay in turning process. Based on this, the time domain simulation of the feedback control with single time delay is carried out, and the advantages and disadvantages of the control are pointed out. Then using the discrete method, the turning dynamics equation is equivalent to a standard discrete state space equation. Based on the linear quadratic optimal control principle, a multi-time-delay controller is designed, and the control effect is verified by numerical simulation. The results show that the time-delay active controller proposed in this paper can effectively improve the stability of turning process and enlarge the stable cutting area. At the same time, the influence of control time delay on control efficiency and control force is discussed. Compared with the turning process, the complexity of the milling process lies not only in the existence of time delay in the system, but also in the periodicity of the rotary cutting motion of the cutter teeth in the milling process, which leads to the periodic variation of the coefficients in the dynamic equation of milling. In this paper, the feasibility of state delay control in milling process is discussed by using semi-discrete method. Then, the time-varying periodic coefficients of the milling dynamics equation are averaged in a period to make it a delay differential equation with constant coefficients. Based on this, an active controller with double delays is designed. Then, the influence of double time delay on control efficiency in milling vibration control is discussed, and the relationship between the unstable region of time delay and the bifurcation characteristics of milling system is discussed. At the same time, it is found that the time delay controller will fail when the period doubling bifurcation occurs in the milling system at a specific speed. In order to solve this problem, the minimum control objective is adjusted to a fixed value to solve the problem of time-delay controller failure to a certain extent.
【學(xué)位授予單位】：上海交通大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2014
【分類號】：TB535

【參考文獻(xiàn)】

相關(guān)期刊論文 前10條

1 ;ACTIVE CONTROL OF A FLEXIBLE CANTILEVER PLATE WITH MULTIPLE TIME DELAYS[J];Acta Mechanica Solida Sinica;2008年03期

2 李忠群;劉強;;立銑加工顫振穩(wěn)定性時域求解與分析研究(英文)[J];Chinese Journal of Aeronautics;2008年02期

3 師漢民;影響機床顫振的幾個非線性因素及其數(shù)學(xué)模型[J];華中工學(xué)院學(xué)報;1984年06期

4 江浩;龍新華;孟光;;銑削主動減振平臺設(shè)計及控制[J];上海交通大學(xué)學(xué)報;2008年05期

5 孫清;劉正偉;伍曉紅;張斌;;含雙時滯振動主動控制系統(tǒng)的穩(wěn)定性分析[J];西安交通大學(xué)學(xué)報;2010年01期

6 孫清;張斌;伍曉紅;薛曉敏;;含雙時滯主動控制系統(tǒng)平凡平衡解穩(wěn)定性的數(shù)值分析[J];西安交通大學(xué)學(xué)報;2010年05期

7 陳花玲,戴德沛;機床切削顫振的非線性理論研究[J];振動工程學(xué)報;1992年04期

8 于駿一,周曉勤;切削顫振的預(yù)報控制[J];中國機械工程;1999年09期

9 李崢;劉強;;基于切削噪聲測試的數(shù)控加工顫振識別系統(tǒng)[J];制造技術(shù)與機床;2009年02期

10 胡海巖,王在華;時滯受控機械系統(tǒng)動力學(xué)研究進(jìn)展[J];自然科學(xué)進(jìn)展;2000年07期

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