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    Please use this identifier to cite or link to this item: http://ccur.lib.ccu.edu.tw/handle/A095B0000Q/234


    Title: 應用操作模態法於工具機主軸適應性轉速切削技術之研發
    Authors: 邱昱?;Chiu, Yu-Sheng
    Contributors: 機械工程系研究所
    Keywords: 顫振穩定界線圖;顫振;操作模態分析法;切削力;Angular velocity vold-kalman filtering order tracking;dynamometer;accelerometer;natural frequency;operational modal analysis;stability lobe diagram
    Date: 2017
    Issue Date: 2019-07-17
    Publisher: 機械工程系研究所
    Abstract: 本論文以訊號量測及操作模態分析法(Operational modal analysis, OMA)為基礎,發展兩項工具機關鍵技術;第一項是工具機最佳切削轉速估測技術;第二項是切削力估測技術。現今工具機朝加工高效率、高轉速、高材料移除率及高精度等發展,此時易因不好的切削轉速而導致顫振(Chatter)發生,進一步影響切削表面及刀具磨耗等問題,因此本研究發展工具機最佳切削轉速預估技術以避免此問題產生。首先鑑別工具機停機狀態之自然頻率、阻尼比以製作顫振穩定界線圖(Stability lobe diagram, SLD),從中獲得初始轉速及切削深度。於初始轉速切削時,以OMA鑑別含切削阻抗之切削系統(含主軸、刀柄、刀具、及工件)自然頻率與阻尼比,並更新顫振穩定界線圖及調變估測轉速,如能周而復始上述步驟,才能使工具機維持穩定切削狀態,此技術經實驗驗證得知考慮切削阻抗進行轉速估測,才能符合真實切削狀況及避免顫振發生,並提升切削表面及延長刀具壽命。切削力(Cutting force)被應用來觀察材料切削性質、顫振監測及預估刀具磨耗等問題。一般量測切削力的方法是使用動力計或透過其他感測裝置進行間接式切削力估測,但此兩方法有價格昂貴、架設不便及可靠度等問題,因此本技術提出以加速規進行切削力估測,以改善上述問題。本技術首先使用實驗模態分析法(Experimental modal analysis, EMA)獲得主軸-刀尖點之轉移函數,並於切削過程中透過主軸上端之加速規訊號與主軸-刀尖點之轉移函數進行切削力估測,接著透過弗德-卡曼濾波階次追蹤濾波器(Angular velocity vold-kalman filtering order tracking, AV VKF-OT)過濾非轉速及刀刃之倍頻以還原真實之切削力。本技術經實驗驗證,得知估測之切削力與動力量測之切削力大小相近,且能還原刀具撞擊工件之切削力波形。
    Two techniques for machine tools based on the operational modal analysis (OMA) are developed in this study. The first is a stable machining technique using adaptive spindle speed. The second is the cutting force estimation technique using frequency response functions. For the stable machining technique, the spindle speed is adjusted optimally according to an on-line machining stability analysis. With two accelerometers attached on the spindle, the dynamic characteristics, i.e. the natural frequency and the associated damping corresponding to the spindle-tool system coupled with the cutting impedance, are identified during the machining process using the operational modal analysis (OMA). With this information, the stability lobe diagram (SLD) which determines the optimal spindle speed is obtained and then the spindle speed is on-line adjusted accordingly. This proposed adaptive spindle speed machining technique is integrated with CNC controller and its performance in machining is assessed experimentally.For the cutting force estimation technique, the purpose is to estimate the cutting force accurately suing accelerometers instead of pricy dynamometers. A frequency transfer function between the force acting on the cutting tool tip and the acceleration on the spindle is determined first using traditional experimental modal analysis (EMA). With this transfer function, the cutting force is then obtained during the machining by measuring the spindle acceleration. Angular velocity vold-kalman filtering order tracking (AV VKF-OT) is utilized to filter out the frequency component induced by the vibration uncorrelated to the cutting force. The cutting force obtained by the proposed method is compared to that measured directly by the dynamometers during the machining to assess the accuracy of the proposed technique. Results show that the estimated cutting force has a similar frequency spectra to that from dynamometer and both force magnitudes are in the same order.
    Appears in Collections:[機械工程學系] 學位論文

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