對於工作路徑或工件外形不明的狀況下，由於無法事先得到預期的路徑或外形，多數的順應性控制器 (Compliant controller) 都失去效用。本文將分別提出模糊控制器及適應性控制器 (Adaptive controller)，應用於機械臂循跡及三次元外形量測系統上。 在執行循跡控制時，將根據量測得到的接觸力，針對其法線方向進行力量控制，而在切線方向進行位置控制，由控制器自動產生預期的工作路徑或工件外形，這是本論文的主要研究目的及貢獻。 在追隨工件的路徑或外形的應用上，傳統上以雷射或 CCD 識別系統來解決這種問題。但是，這種雷射或 CCD 識別系統相當複雜，而且會受限於環境的狀況。本論文採用的模糊控制器及適應性控制器，可以自我調適 (self-tuning)，讓機械臂可以自動追隨不明的路徑或外形。在機械臂上裝置終端效應器 (end-effector)，其中具有力量感測器 (force sensor)。力量感測器可以量測接觸力的大小及方向，藉由解析及控制接觸力的大小和方向，來決定不明的工作路徑或工件外形的軌跡。 在本論文中，發展出自我調適的模糊控制器，當機械臂接觸到工件時，控制器依據維持接觸力法線方向的大小不變的原則，控制終端效應器的位置，並根據接觸力的切線方向，決定機械臂的行進方向。重複這種不斷的調整及移動，最後即可決定出期望的工作路徑或工件外形。實驗結果顯示，應用這種控制器來尋找工作路徑或量測工件外形，都可以得到相當不錯的結果。這個方法可以應用於自動焊接系統的焊道循跡、機械工件去毛邊及倒角、3D工件外形量測...等。 For the case of unknown contour, most controllers for compliant motion fail since the desired trajectory cannot be obtained. However, in this study, when performing compliant motion, with the magnitude of the contact force remains constant, the desired trajectory is generated from the controller based on the tangential direction of the measured contact force, which is the major merit of our paper. For the application of tracking the path on the workpieces, the laser system or CCD (Change Couple Device) identification system is generally used as one of the popular resolutions. However, the implementation of laser system or CCD identification system is highly complex and environmental-limited. This study presents a functional compliant motion controller by applying the self-tuning fuzzy control to have a robot manipulator implement tracking tasks on the unknown paths. The manipulator has its end-effector installed with a force sensor. With the aid of the self-tuning fuzzy controller, this control system results the smoothly path-tracking on a workpiece. A radius compensating method is used to correct the measured data and then leads to the “real” path or contour of the workpiece. The experiments performed have successfully demonstrated the feasibility of the proposed control algorithms. For anothor study in this paper, our design of the controller is based on adaptive control scheme. The position and the contact force of end-effector are controlled by feed forward and feedback controller. By applying these controllers, the manipulator can be adapted to the curved surface of environment, and can have close contact with the curved surface. The contour of workpieces can then be measured accordingly.
