臺灣博碩士論文加值系統

顫振(chatter)是在切削加工的過程中一種自發性的振動，會造成工件和刀具產生激烈振動，因此降低工件的表面精度、限制材料移除率更甚者使得刀具磨損或斷裂，此現象在加工細長型工件時更為明顯，因此若能抑制顫振則能提昇加工性能。
本研究針對車削細長型工件的顫振抑制問題加以探討，設計一個壓電致動刀具以取代傳統刀具，並基於H∞控制理論設計控制器，輸入控制電壓驅動壓電致動刀具，動態改變車削深度，達到抑制顫振的目的。
本文分別應用有限元素分析法及實驗模態分析法，鑑別出精確的切削力對工件位移、切削力及控制電壓對壓電致動刀具位移的轉移函數，以供設計控制器之用。
由顫振理論可知，顫振的發生和與工件和刀具的結構動態轉移函數有重要關聯，因此本文基於模式匹配(model matching)的觀念，設計控制器使工件和刀具的結構動態轉移函數具有較高的穩定邊界，並應用H∞控制理論設計控制器。先以電腦模擬驗證控制系統的性能，再應用dSPACE建構一個實驗架構，包含實體的壓電致動刀具和電腦模擬的車削動態實驗架構，做進一步驗證。本文將車床改裝，以架設壓電致動刀具，進行實際的車削實驗。在相同的車削條件下，比較傳統刀具、未控制的壓電致動刀具和加入H∞控制器的壓電致動刀具之車削效果，驗證本文提出的H∞控制器能有效抑制顫振。

Chatter is a self-excited vibration during machining that causes violent vibration between the tool and the workpiece. Chatter degrades surface finish, causes wear or breakage of tools and limits the material removal rate. This phenomenon is more conspicuous on slender workpiece. Therefore, the ability to suppress chatter can improve machining performance significantly.
In this study, the chatter suppression problem is investigated for slender workpieces in turning. A tool holder driven by a piezoelectric actuator is designed and controlled. Based on the H∞ controller may change the chip width dynamically by controller signal voltage for chatter suppression in the turning process.
Experimental modal analysis and ANSYS finite-element modal analysis are carried out for obtaining accurate frequency response functions of the workpiece and the cutting tool for designing controllers.
According to the chatter theory, the happening of chatter has important relation to the structure’s dynamic transfer function of the workpiece and cutting tool. Based on the model matching conception and applied H∞ control theory to design a controller to have the higher critical stabile value of the structure’s dynamic transfer function. The performance of controller is tested first in a simulative environment, then an experimental structure is built by utilizing dSPACE, include of the real cutter and the computer-modelling workpiece and cutting status. To proceed with the machining experiment, the lathe was refitted to mount the piezo-actuated tool holder. Compared with the results of cutting by traditional tool holder and uncontrolled piezo-actuated tool holder and controlled piezo-actuated tool holder under the same cutting condition, to make sure the H∞ controller possess the ability of chatter suppress effectively.

中文摘要 i
Abstract ii
目錄 iv
圖目錄 vi
表目錄 ix
第一章　緒論 1
1.1　研究背景 1
1.2　國內外相關研究 2
1.3　研究目的 3
第二章 車削顫振模式與強健控制器理論 5
2.1　車削顫振模式 5
2.1.1　傳統刀具顫振模式 5
2.1.2　壓電致動刀具顫振模式 8
2.2　強健控制器設計 10
2.2.1　控制器設計概念 10
2.2.2　控制器的模式匹配 11
2.3　強健控制器理論 13
2.4　控制器降階 17
第三章　系統識別 18
3.1　切削力對刀具位移的系統識別 18
3.2　控制電壓對刀具位移的系統識別 20
3.3　工件的系統識別 21
第四章　強健控制器模擬 22
4.1　強健控制器性能 22
4.2　車削系統的控制器性能模擬 24
4.2.1　未控制的車削系統模擬 24
4.2.2　加入控制的車削系統模擬 25
4.3　即時控制模擬實驗 27
4.3.1　實驗設備與實驗架構 27
4.3.2　正弦切削力輸入模擬實驗 28
4.3.3　車削顫振模式模擬實驗 29
第五章　車削實驗與結果 31
5.1　未控制的實際車削實驗 31
5.1.1　實驗設備 31
5.1.2　未控制的車削結果 32
5.1.3　顫振現象分析 33
5.2　加入控制器的實際車削實驗 38
5.2.1　實驗架構 38
5.2.2　車削實驗結果 39
5.3　工件表面粗度量測實驗 40
5.3.1　工件表面粗度量測方法 40
5.3.2　實驗結果 42
5.3.3　實驗結果比較 53
第六章　結論 55
參考文獻 56
附錄　壓電致動元件驅動電路製作 58
A1　製作目的 58
A2　壓電驅動電路架構 59
A2.1　運算放大器 59
A2.2　壓電驅動電路 60
A2.3　壓電驅動電路模擬 61
A3　實驗與實驗結果 62

[1] MERRIT, H. E., “Theory of self-excited machine-tool chatter,” Journal of Engineering for Industry, pp.447-454, November 1965.
[2] Frankpitt, B. A., A model of the dynamics of a lathe toolpost that incorporates active vibration suppression. Technical Report, Institute for System Research, University of Maryland, College Park, 1995.
[3] Eshete, Z., In process machine tool vibration cancellation using electrostrictive actuators. Ph.D. dissertation, Institute for System Research, University of Maryland, College Park, 1996.
[4] G. Pan and H. Xu, “Modeling and intelligent chatter control strategies for a lathe machine,” Control Engineering Practice, Vol.4, No.12, pp.1647-1658, 1996.
[5] S. K. Choudhury, N. N. Goudimenko and V. A. Kudinov, “On-line control of machine tool vibration in turning,” International Journal of Machine Tools & Manufacture, Vol. 37, No. 6, pp. 801-811, 1997.
[6] D. Liu, J. W. S., K. S. Moon, T. J. Sturos and R. Kashani, “Surface texture improvement in the turning process via application of a magnetostrictively-actuated tool holder,” ASME Journal of Dynamic Systems, Measurement, and Control, Vol. 120,pp. 193-199,1998.
[7] J. D. Kim, D. S. Kim, “Waviness compensation of precision machining by piezoelectric micro cutting device,” International Journal of Machine Tools & Manufacture, Vol. 38, pp. 1305-1322, 1998.
[8] Andrew Woronko, Jin Huang, and Yusuf Altintas, “Piezoelectric tool actuator for precision machining on conventional CNC turning centers,” Precision engineering, vol. 27, pp. 335–345, 2003.
[9] Min Chen and Carl R. Knospe, “Control Approaches to the Suppression of Machining Chatter Using Active Magnetic Bearings,” IEEE transactions on control systems technology, vol. 15, No.2, March 2007.
[10] Tarng, Y.S., J.Y. Kao, and E.C. Lee, “Chatter suppression in turning operations with a tuned vibration absorber,” Journal of Materials Processing Technology, vol.105, pp. 55-60, 2000.

[11] Tarng, Y.S. and E.C. Lee, “A critical investigation of the phase shift between the inner and outer modulation for the control of machine tool chatter,” International Journal of Machine Tools and Manufacture, vol. 37, No. 12, pp. 1661-1672, 1997 .
[12]Zhou, K. and J.C. Doyle, Essentials of robust control. Prentice-Hall, 1998.
[13] Shahian and Hassul, Control system design using Matlab. Prentice-Hall, 1993.
[14] Gu, Da-W, Petkov, P.Hr., and Konstantinov M.M., Robust Control Design with MATLAB. Springer, 2005.
[15] T. Delio, J. Tlusty and S. Smith, “Use of Audio Signals for Chatter Detection and Control,” Journal of Engineering for Industry, vol. 114, pp. 146-157, 1992.
[16] Goro Obinata and Brian D.O. Anderson, Model Reduction for Control System Design, New York, Springer, 2000.
[17] 王詠傑，“應用於車削的主動式減振控制的壓電致動刀具設計”， 逢甲大學自動控制工程研究所，碩士論文，民國95年。
[18] 江曉鈴，“壓電致動器於精密加工的主動式控制研究”， 逢甲大學自動控制工程研究所，碩士論文，民國96年。