臺灣博碩士論文加值系統

中文摘要

顫振是在切削加工的過程中一種自發性的振動，在工件和刀具之間產生劇烈振動，因此降低工件的表面精度、限制材料移除率甚至降低刀具使用壽命，若能抑制顫振則能夠提昇加工性能。
顫振現象在加工細長形工件時更容易發生，本文設計一個新式的壓電致動刀具取代傳統刀具，以抑制車削細長形工件的顫振，本文建立更詳細的壓電致動刀具車削的顫振模式，設計控制器時，考慮切削力對工件位移的轉移函數不容易精確鑑別，且在車削過程為時變的問題，因此採用回授式濾波型最小均方演算法設計適應性控制器。
以電腦模擬測試控制器性能，模擬結果顯示控制器能有效抑制車削顫振的發生。透過進行實際車削實驗，比較未控制車削與加入控制器的車削結果。結果顯示在加入控制器之後，工件各區段的表面粗度皆明顯低於未控制的車削結果，因此設計的控制器於實際車削時的顫振抑制效果獲得驗證。


關鍵字：顫振、控制、車削、車床

Abstract

“Chatter” is a kind of self-excited vibration in the process of cutting. It corresponds to the relative displacement between the workpieces and cutting tools. Hence it lowers down the surface finish of workpieces, limits the material removal rate (MRR), and reduces the service life of cutting tools. Improvement of the performance of machining is surely expected provided chatter effect is suppressed.
Chatter is more likely to happen in the cutting of slender workpieces. In this study, a novel piezo-actuated toolholder is designed to replace the traditional one in turning operation. It is intended to suppress the chatter effect in the turning of slender workpieces. A more detailed chatter model for the piezo-actuated toolholder is also derived. Considering that the transfer function from the cutting force to the workpiece displacement is time-varying and cannot be precisely determined in easy ways, the “feedback filter-x least mean square, feedback FXLMS” algorithm is employed to design an adaptive controller for suppressing chatter.
The performance of the designed controller is tested through computer simulation. Simulation results indicate that the controller is able to inhibit the onset of chatter in turning. Turning experiments are carried out for comparing the surface finish in controlled turning and uncontrolled turning. The results show that the surface roughness in each section of the workpiece is significantly improved in controlled turning. Therefore, the effectiveness of the designed controller in the suppressing of chatter is verified.


Keywords: chatter, control, turning, lathe

目錄

中文摘要 v
Abstract vi
目錄 vii
圖目錄 ix
第一章 緒論 1
1.1　研究背景 1
1.2　國內外相關研究 3
1.3　研究目的 5
第二章 顫振模式與控制器理論 6
2.1 車削的顫振模式 6
2.1.1傳統刀具顫振模式 6
2.1.2 壓電致動刀具之設計 9
2.2 主動式壓電致動刀具控制系統 11
2.2.1 壓電致動刀具車削顫振理論 11
2.2.2 控制的壓電致動刀具車削顫振模式 13
2.3　FXLMS適應性控制器之設計 15
2.4　FXLMS適應性控制器應用於車削加工之設計 17
第三章 系統識別 19
3.1 控制電壓對刀具位移的系統識別 19
3.2 切削力對刀具位移的系統識別 21
3.3 工件的系統識別 23
第四章 控制器模擬 26
4.1 控制器性能 26
4.2 控制器模擬 29
4.2.1 未控制的壓電致動刀具顫振模擬 29
4.2.2 控制的壓電致動刀具顫振模擬 31
第五章 實際車削實驗與結果 35
5.1 壓電致動刀具車削實驗設備與架構 36
5.2 工件表面精度測量方法 38
5.3 實驗以及表面粗度量測結果 41
5.4 實驗結果比較 46
第六章 結論 49
參考文獻 50

參考文獻

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