本論文提出一新控制器切換策略應用於自動鑽削作業上，以解決鑽頭碰觸工件之瞬間所產生的衝擊情況，並且在鑽孔時維持一期望之切削力進行鑽削。回顧傳統自動鑽削上所使用的控制器通常為position-based PID以及force-based PID控制器兩種。使用傳統position-based PID控制器進行鑽削時，除非進刀速率降到合理範圍，否則將無法避免衝擊情況的發生；此外，使用此控制器無法在鑽孔時維持一特定切削力。另一方面，使用傳統force-based PID控制器進行自動鑽削作業時，此控制器無法讓鑽頭沿著期望的位置軌跡靠近工件，並且，當碰觸工件時將產生極大的衝擊力。因此，本文所提出之新控制器切換策略大大的改善了傳統position-based PID以及傳統force-based PID控制器應用於自動鑽削作業的缺點。
本文所提出的控制策略，其以控制器間自動互作切換之方式，以結合兩控制器特性於一體。在鑽頭行經至工件與接觸工件之瞬間，本文使用機械臂之阻抗控制的概念，使得鑽頭碰觸工件時產生順應之效果，避免衝擊情況之發生。而在鑽孔時，則使用力量PID控制器以維持一期望之切削力達到良好的鑽削性能。在阻抗控制器以及力量PID控制器切換部分，本文使用了CMP函數當作切換之依據，藉此達到bumpless transfer的切換目標。由於實際的鑽床系統充滿了許多不確定性，因此本文在此使用了適應阻抗控制器代替原本的阻抗控制，並經過嚴謹的數學推導，證明其可行性。最後，本文亦以實驗來證明新控制器切換策略之控制效果並與傳統的控制方法做比較。

This paper focuses on the automatic drilling controller design which is able to avoid the impact force when the drill bit hits the work-piece and can maintain a constant force during cutting process. It is noted that in the classical position-based PID control of the automatic drilling process, the impact force is unavoidable unless the feed rate is lowered to a considerable amount. Meanwhile, the cutting force can not be regulated to a desired value. On the other hand, the conventional force-based PID controller in the automatic drilling system may not guide the drill bit to the work-piece in a desirable trajectory, and a significant impact is also unavoidable. Therefore, the controller proposed in this thesis gives enormous improvement than both the position-based as well as the force-based PID controllers.
The strategy proposed in this thesis employs the impedance control concept from robotics to have a compliant interaction between the drill bit and the work-piece so that the impact force is properly accommodated. The force-based PID is used to regulate a desired force to give proper cutting performance. The switching between the impedance controller and the force-based PID is accomplished by using a CMP function so that a bumpless transfer can be obtained. Due to the uncertainties in the system model, the impedance controller is developed in its adaptive version with rigorous mathematical justifications. To verify the effectiveness of the design, an experimental setup is built. The results are satisfactory compared with traditional designs.

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