- 學位論文
五軸工具機循跡控制實驗驗證
Experimental Verification of Contouring Control for Five-axis Machine Tools
摘要
五軸工具機在市面上已經 越來越普及，然而由於其複雜的非線性問題，高精度難以達到，因此本團隊提出一套等效誤差法應用於五軸循跡控制器，等效誤差法有別於傳統，具有幾項優點: (1)直接以路徑方程式設計輪廓誤差，因此不會有輪廓誤差近似的問題;(2)它可以應用於多軸的運動系統。 等效誤差法應用於五軸工具機的實驗已有前人做過，然而以前做過的實驗路徑不外乎直線或圓，頂多就一條簡單的曲線，為了使該實驗更加完善，本論文選取實際的牙模加工路徑，使用等效誤差法控制五軸工具機追循該路徑，要使用等效誤差法首先必須要有路徑方程式，因此會先針對牙模路徑NC碼擬合成分段多項式曲線，每段路徑末端與下一段路徑的起點位置、斜率需一致，該位置稱之為轉折點，循跡時在轉折點的位置輪廓誤差容易上升，因此在控制器裡會加入一些條件使遇到轉折點時輪廓誤差降低，為了避免機台晃動，接著會對擬合路徑做S型加減速規劃，且為了消除系統的非線性，會使用Lagrangian法推導五軸工具機的系統動態方程式，整合系統方程式及等效誤差法，並加入積分滑動模式控制(ISMC)增加強健性，整個合成一個完整的循跡控制器，接著會藉由MATLAB/Simulink模擬各軸的運動狀態，最後再將設計好的控制器應用於五軸工具機證明該理論可以應用於複雜路徑的加工。
並列摘要
five-axis machine tool has become increasingly popular in the market. However, due to its complex nonlinear problems, high precision is hard to attain. Thus, this team proposes a method of equivalent error to apply to five -axis contouring controller. The method of equivalent error is different from tradition. It has several advantages: (1) contour error is directly designed by path equation, so it has not the problem of contour errors approximation; (2) It can be applied to multi-axis motion systems. Experiment of the method of equivalent error is applied to five-axis machine tool has been done before. However, previously experimental path nothing else but line or circle. At most, a simple curve. In order to make experiment more perfect, this paper chooses the actual path of dental mold. five-axis machine tool is controlled to tracing the path by the method of equivalent error. First, the method of equivalent error need to have path equation, so NC code of dental mold will being fitted piecewise polynomial curve. Position and slope must be the same between each end of the segment of the path and start of the next segment of the path. The position is called “turning point”. Contour error easily rises in turning point when tracking. So, it will adding some conditions in controller make contour error reduce when it encounters turning point. In order to avoid machine shaking, fitting path will be planning by S-type acceleration and deceleration. And in order to eliminate systemic nonlinear, dynamic equation of five-axis machine tool is derived by method of Lagrangian. Integrated systemic equation and method of equivalent error and add integral sliding mode control (ISMC) increased robustness. Entire compose a complete contouring controller. Then, it will be simulation of motion of each axis by MATLAB/Simulink. . Finally, it will be applied to five-axis machine tools by designed controller to prove the theory can be applied to complex machining path.
參考文獻
延伸閱讀
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