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    Please use this identifier to cite or link to this item: http://ccur.lib.ccu.edu.tw/handle/A095B0000Q/139

    Title: 應用強健性進給率控制與動態彈性變形補償於工具機高速高精控制技術之研發;Application of Robust Feedrate Control and Dynamic Elastic Compensation for High Speed and High Precision Control of Machine Tool
    Authors: 黃泓緯;HUANG, HONG-WEI
    Contributors: 機械工程系研究所
    Keywords: 進給系統;彈性變形補償;強健性進給率控制;Feed drive system;Elastic deformation compensation;Robust feedrate control
    Date: 2018
    Issue Date: 2019-05-23 12:52:41 (UTC+8)
    Publisher: 機械工程系研究所
    Abstract: 在本文中提出補償因彈性變形所造成位置誤差之方法以及具強健性之適應性切削控制器以提高工具機在位置精度與加工效率方面之性能。在提升精度方面,針對彈性變形所造成的位置誤差提出彈性變形補償插補法則。應用所提出的方法可大幅降低彈性變形效應,以提高未使用光學尺工具機之定位精度。首先建立具撓性之傳動系統動態模型,其包含底座,軸向模態,扭轉模態、伺服控制迴路以及摩擦效應以探討其動態行為。彈性變形方程式可根據所建立的動態模型進行推導得到,並透過分析完整彈性變形公式後可將公式進一步簡化成平台慣量,阻尼所產生的力造成之變形。在本文中使用具光學尺之雙軸平台進行實驗並將實驗所得之彈性變形結果與動態模型之模擬結果以及彈性變形公式進行比較後可驗證所推導彈性變形公式與動態模型之正確性。在驗證其正確性後,根據所推導之簡化彈性變形公式,提出彈性變形補償插補法則。從彈性變形補償實驗結果中可知,透過本文所提出的補償方法可大幅降低彈性變形誤差的最大值與與方均根值,進而提高定位精度。另一方面,為了提高工具機加工效率,本文透過量化回授理論設計了一個具強健性之進給率控制器。透過所提出的強健性控制器,即使在加工過程中切削條件發生變化,仍可將切削力控制在一個固定值進而提高加工效率。為了達到進給率控制以調變切削力的目的,首先針對伺服模型與切削模型進行推導與參數鑑別。並透過所推導之切削模型在不同加工條件下所產生的特性變化建立系統不確定性以設計具強健性之控制器。最後經由不同切削條件下(如不同刀具、工件材質)的實驗驗證所提出之強健性進給率控制器之性能。
    To achieve high speed and high precision control for machine tools, two approaches which the elastic deformation compensation for increasing positioning accuracy and the robust feedrate adaptation for enhancing the milling efficiency are proposed to improve the performance of machine tools in this study.The first one is to develop a novel interpolation algorithm to compensate the error caused by elastic deformation which can achieve higher tracking accuracy even without the signal from the linear scale on the table. First, a dynamic model which considers flexural modes of a feed drive system, servo control loops, and friction effects simultaneously is constructed. Based on the dynamic model, the equation of elastic deformation is then derived. The equation is further simplified to form a formulation in computing the deformations which is mainly caused by inertial and viscous forces during motion. Experiments and simulations are conducted to validate both dynamic model and the simplified elastic deformation equation. Based on the simplified equation, a novel elastic deformation compensation interpolation (MEDCI) algorithm is proposed to generate the modified position commands such that the tracking errors caused by elastic deformation can be reduced. Experimental results under linear trajectories demonstrate that the proposed algorithm could reduce the maximum elastic deformation error from 0.0234 mm to 0.0064 mm and the root mean square (RMS) error from 0.0195 mm to 0.0031 mm which are 84.1% and 72.6% reduction, respectively. Furthermore, the MEDCI can achieve more than 10% reduction of the RMS elastic deformation error as compared to the compensation approach used in published literature.The second one is to utilize quantitative feedback theory (QFT) to design a robust controller with consideration of varying cutting conditions. The servo dynamics and milling process models are identified first. The effects of different milling parameters on the dynamic model are evaluated to build the system uncertainties to the nominal plant. Instead of using the force measured from dynamometer, the robust controller adjusts the feedrate according to the spindle current which is easy to measure online. Simulation and experimental results illustrate that the cutting force could maintain at a constant level under different cutting depth. The machining time can be reduced for over 20% than the uncontrolled cases. Finally, the robustness of the proposed controller is validated by applying different tool, workpiece material and cutting parameters in the experiments.
    Appears in Collections:[機械工程學系] 學位論文

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