http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/36 2026-03-10T11:51:30Z http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/24895 標題: 齒輪機構之運動特徵分析與合成; Kinematic Characteristics and Synthesis of Geared Mechanisms Using the Concept of Kinematic Fractionation 作者: Yu-Ching Yeh; 葉又菁 摘要: 本論文主要利用運動分解的概念進行齒輪機構運動的特徵分析與合成，以及經由運動特徵進行齒輪機構的分類。齒輪機構可被分解為數個單自由度的運動單元，每個運動單元則被視為齒輪機構內的運動傳輸模組。運動單元間的拓樸構造連接可分為雙鏈結型與同軸三角型，內文將分析內含四個運動單元，單自由度至六桿，以及兩個自由度至七桿的齒輪機構，並且說明及表列其對應的拓樸構造；藉由選擇輸入與輸出端的位置，可得到齒輪機構內所有可能的運動傳輸路徑並將路徑以控制區塊圖表示。利用控制區塊的增益計算公式，將輸入端與輸出端的運動關係公式化為增益矩陣。 接著進一步討論運動單元內部條件對整體運動增益的影響；運動單元內輸出入桿件的不同及運動單元間的共同連接部分的接頭條件會共同影響整體增益的表現形式，利用增益表現形式的差異可將內含四個運動單元，單自由度至六桿，以及兩個自由度至七桿的齒輪機構做完整分類，根據增益型式分類及運動特徵可得到功能導向之齒輪設計方法。; A methodology based on the concept of kinematic fractionation for the revelation of kinematic characteristics and classification of geared mechanisms is presented. It is shown that structurally non-fractionated geared mechanisms can be considered as the combination of kinematic units (KUs). Each KU is considered as the basic motion transmission module inside a geared mechanism. Admissible connections of KUs are identified according to the structural characteristics of one- and two-DOF geared mechanisms of up to four KUs. Such configurations are then used to construct possible propagation paths of motion via the assignments of input and output links. Since the propagation paths can be modeled by the control block diagram problems, the kinematic relations between input and output links are formulated to gain matrices. According to the types of entities in a gain matrix, various kinematic behaviors are disclosed. The complete kinematic behavior of single KU is revealed and three gain forms of KU is basic of global gain since the geared mechanism is combination of KUs. The global gain of the mechanism is determined by three factors: the configuration decides the transmission flow at KU level, the common linkage between KUs of the mechanism limit the thin edge type of local input and output in the connection of KUs, the assignment of input, ground and output decides the thin edge type of global input and output. From the factor of global gain, there are three gain type are identified and characteristics of geared mechanism are more clear. It is believed that such kinematic characteristics can be readily transformed into the functional requirements and synthesis of geared mechanisms of up to four KUs can be accomplished much easier. 2007-01-01T00:00:00Z http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/46934 標題: 黃銅線及鍍鋅線應用於線切割之性能研究; A Study on the Performance of Brass and Zinc-Coated Wire Electrodes in WEDM 作者: Yu-Ju Lee; 李育儒 摘要: 線切割加工能使用的線電極種類繁多，但線電極對加工性能的影響過去未見討論。本研究欲探討線電極對加工特性之影響，以提供未來線電極設計之參考。文中使用鍍鋅線與黃銅線，進行不同加工道次切割數種厚度的SKD-11材料。結果顯示鍍鋅線不僅在面切割速度上優於黃銅線，在工件上也呈現更好的形狀精度以及更優異的表面粗糙度。導致此差異的原因可歸納為三大基本因素，分別為熱、電與汽化的性質。研究中針對鍍鋅線與黃銅線在熱、電與汽化相關等特性設計實驗，整合實驗結果可發現使用鍍鋅線做為線電極材料，其表面的多孔結構可增加線電極與加工液接觸的面積，協助熱量的排除，並因為鍍鋅線有較低的熔點與沸點，因此較容易發生汽化帶走熱量，而具有較佳的熱量排除機制；另外由於鍍鋅線有較低的電子親合能，在放電加工過程中會產生較大的放電間隙，配合上鍍鋅線的低沸點與高飽和蒸氣壓，於加工中產生大量氣體，使放電渣較容易排除，而達到較佳的清洗性。最後本研究歸納了各種在放電加工上影響線電極效果之因素，建議如欲改善黃銅線之加工效能，可將黃銅線的表面改成多孔結構，以協助熱量排除；如欲發展新線種，可設計多層不同材質的線電極，例如最內層選用鉬或鎢等高剛性、高熔點材料，中間層則選用導電性良好的黃銅或純銅，最外層則鍍上一層鋅，此種新型電極應可滿足線電極的所有需求。預期有極佳的剛性、優異的導電率、優良的熱量排除機制以及良好的清洗性。; Many kinds of wire electrodes were used on wire electric discharge machining (WEDM), but the research of the wire electrode has few been discussed. In this study, the impact of wire electrode will be discussed, in order to be the reference of design the wire electrode in the future. In the article, brass wire and zinc-coated brass wire were used as electrodes in WEDM. Experiments were conducted with different workpiece thicknesses and different cutting processes. And material SKD-11 was used as the workpiece. According to the experimental result, zinc-coated brass wire is not only good at machining speed but also can form good shape accuracy and good surface roughness. It could be concluded that the three basic elements like heat, electric and evaporation were the main factors. This study focused on these three basic physical properties of zinc-coated brass wire and brass wire, and also designed and conducted the experiments with the characteristics of heat, electric and evaporation. It is discovered that there are some micro holes on the surface of zinc-coated brass wire while it is used as an electrode. Hence, the contact area between the fluid and the wire electrode will increase and that will lead to a better heat removal, being easy to evaporate and a better cooling mechanism because of the lower melting point and boiling point of zinc-coated brass wire. Moreover, the lower electron affinity of zinc-coated brass wire would lead to the larger gap distance during WEDM process. And with the characteristics of lower boiling point and induced higher saturated vapor pressure, zinc-coated brass wire can produce much more vapor resulting that the discharge debris could be easily eliminated to achieve the better flush-ability. At last, this study has figured out all the factors which can influence the efficiency of wire electrode and machine efficiency. A design with multi layers of electrode composed of different materials like the most inner layer with molybdenum or tungsten material with high boiling point and stiffness, the median layer with brass or copper which is good at conductivity and the outer layer with zinc-coated was proposed as an innovative electrode design. Multi-layer wire electrode would be the optimum choice to obtain a good stiffness, conductivity, heat removal rate and debris eliminating. 2010-01-01T00:00:00Z http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/68849 標題: 麥克風陣列結合波束成型理論進行聲源定位及應用聲學攝影機於加工系統之振噪分析 ; Using Microphone Arrays with Beamforming in Sound Source Localization and Application of Sound Camera for Noise and Vibration Analysis of Machining Systems 作者: Tzu-Yin Su; 蘇紫茵 摘要: 就像人有兩個耳朵一樣，多個感測器組成陣列後可以進行聲源定位。此技術應用廣泛，從早期用於軍事科技，到現代智慧聲控裝置或輔助工業噪音檢測，皆能見到其蹤影，亦是一項發展已久的技術，研究者也努力從陣列排列方式或演算法優化追求提升定位精準度及運算速度。 本研究首先將聲音感測器以直線的方式排列建立一維等間距線性陣列系統，並使用波束成型演算法進行聲源定位，進而建構完整的自動聲源追蹤系統；接著為了追蹤空間中的聲源位置，以一維陣列系統為基礎建立二維的聲源定位陣列，利用不同的排列形式設計各種陣列幾何的配置，並探討對應的聲源辨識能力與解析度，進而找出最佳的陣列排序方式；接著將二維陣列系統與工業相機結合，建立出可視化的聲場量測系統，並設計靜止、二維移動和三維空間移動的聲源實驗，測試此系統的靈敏度與定位能力；最後將本系統與三維數位影像相關法（digital image correlation，DIC）結合可精準定位聲源的三維空間位置，並將分析結果與市售的聲學攝影機相互比對以驗證本系統之可行性。另一部份則是將聲源定位應用於振噪分析的實例研究，與傳統量測工具相互搭配，針對內藏式主軸、馬達加工系統與機械手臂三種不同加工系統進行量測，將運轉訊號分離出環境背景噪音、電子元件噪音與運轉機械噪音並分項討論，也從異常訊號特徵推論結構有零件鬆動、基座不穩等問題，並成功使用聲學攝影機找到發出異音的缺陷軸承；最後則將聲學攝影機拍攝結果相互比較，討論聲源定位技術於實例應用的可行性。; Similar to human’s two ears, the sound can be “heard” and localized by the sensor array. This technology is widely used in many fields from military technology at early stages to smart voice control devices or assisting industrial noise detection. This technique has been developed for a long time. Researchers usually focus on the topics for the location of those sensors that were placed or developing the algorithm in order to improve locating accuracy, precision, and speed. This study starts with 1-D array system with uniform arrangement, using beamforming algorithm in sound source localization and constructs an automatic source tracking system. For tracking the sound source in space, it carries on 2-D array system and discussed different geometric forms of the array with their locating ability and resolution, therefore finding out the best arrangement. Next combines this 2-D system with industrial camera to practicing an acoustic source visualizing system and then tests its sensitivity and locating ability by tracking a steady sound source, moving in a plane and in space. Lastly, combines this 2-D sound source tracking system with 3-D digital image correlation can locate the sound source in a 3-D space and compare the experimental results with those from a commercially available product, sound camera, to evaluate the system. The other part of this thesis is noise and vibration analysis, which cooperates this sound source localization technology with traditional measurement tools such as microphone and accelerometer. In these 3 cases, which include built-in high-speed spindle, machining system, and robotic arm, this study separates the operation signal for background noise, electronic components noise and mechanical noise from the machines. Finally, the capability of the practical application of sound source localization technology is discussed by the measuring results of the sound camera in these cases. 2020-01-01T00:00:00Z http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/96327 標題: 麥克風陣列安裝角度誤差對刀具磨耗偵測之預測準確度的影響; Study on the Impact of Microphone Array Installation Angle Error on the Prediction Accuracy of Tool Wear Detection Systems 作者: 連廷勳; Ting-Hsun Lien 摘要: 在銑削加工中，刀具的狀態是一個重要的指標，且會影響整體加工的品質，所以刀具磨耗的偵測系統就格外重要。雖然在過去的經驗裡，常透過有經驗的操作人員來聽聲音的變化以及其他現象進行判斷。不過為了提升加工便捷、操作簡單化以及提高可靠度，應透過感測器來收集相關訊號，以及透過機器學習來預測刀具磨耗的狀態。 本研究透過麥克風當作感測器，其目的是可以透過非接觸式的方式進行訊號偵測，易於安裝及調整感測器的位置，相較於接觸式感測器，限制較少。過去的研究為了提高實驗的重覆性，通常仔細校準麥克風的位置與角度，以降低實驗時的誤差。然而，實務上可能在安裝麥克風時會有些許角度的誤差，文獻中並未有研究討論到安裝麥克風的角度誤差對預測準確度的影響。本研究在實驗過程中除了單一麥克風外，會透過三支麥克風組成麥克風陣列進行聲音訊號處理，其方式稱為波束成型法(Beamforming)，分別為延遲加總波束成型法(Delay-and-Sum Beamforming, DSB)與最小方差無失真響應波束成型法(Minimum Variance Distortionless Response, MVDR)之方法進行實驗。除此之外，透過群組分離準則以及特徵選取，將刀具磨耗指標進行分類，再利用費雪線性區分法(Fisher linear discriminant)建立刀具偵測系統，預測刀具磨耗的狀態。 實驗結果顯示在小角度的變化之下，可有效地透過MVDR波束成型法補償。相對於對準聲源的情況下準確率可以到93%，麥克風與聲源夾角為5度下，透過MVDR可以將準確率最大從75%上升到88%，角度誤差為10度的情況下，透過MVDR有效將準確率從最大從68%上升到82%。不過觀察到角度越大，能補償的有限，但在10度以內，補償後的預測準確度可以來到80%以上。; In milling operations, the condition of the cutting tool is essential to determining the quality of machining. Therefore, an effective tool wear detection system is crucial. In the past, experienced operators would often rely on auditory cues and visual observations to assess tool conditions. However, to improve convenience, simplify operations, and enhance reliability, it is more effective to utilize sensors to collect relevant signals and apply machine learning techniques to predict tool wear. In this research, microphones are used as sensors for contactless signal collection. This approach allows for easy installation and adjustment of sensor positions, offering more flexibility compared to contact sensors. Furthermore, the study investigates the accuracy of tool wear prediction by analyzing acoustic signals captured at different angles using microphones. To this end, the experimental setup allows the microphone positions to be adjusted freely. The experiments involve both individual microphones and a three-microphone array, utilizing acoustic signal processing methods known as beamforming. The two beamforming techniques employed are Delay-and-Sum Beamforming and Minimum Variance Distortionless Response. In addition, group separation criteria and feature selection are applied to classify tool wear indicators, followed by the use of Fisher Linear Discriminant for tool wear detection to predict tool wear accuracy and establish tool life standards. The results indicate that small angular deviations can be effectively compensated using the MVDR beamforming method. Compared to the scenario where the microphone array is perfectly aligned with the acoustic source, achieving an accuracy of 93%, MVDR improves the accuracy from a maximum of 75% to 88% at a 5-degree angle error. For a 10-degree angle error, MVDR effectively raises the maximum accuracy from 68% to 82%. However, it was observed that the compensation becomes limited as the angle increases. Nevertheless, for deviations within 10 degrees, the post-compensation prediction accuracy remains above 80%. 2024-01-01T00:00:00Z