內含DDOB與加速度迴路之穩健精密運動控制器設計

Abstract

為了要使運動系統的精密度提升，首先要降低命令路徑之誤差與輪廓誤差。而系統常因外界的干擾（如摩擦力，負載變化）而影響精密度。本研究是利用一設計良好的整合型控制器為出發點。在系統的大部分追跡誤差以及輪廓誤差已被抑制的情況下，再利用數位式干擾觀測器（digital disturbance observer, DDOB）來改善因摩擦力所造成的Stick-Slip現象，使得輪廓誤差的極大值能夠降低。同時，當負載發生變化時，系統的穩健性較佳。另外，在設計整合型控制器時，將系統的加速度迴路考慮其中，可利用加速度迴路較高的頻寬與較快的速度響應，並可降低系統模型不確定性，來改善系統的輪廓誤差與追跡誤差。在負載發生變化時，使用考慮加速度迴路的控制器擁有較佳的穩健性。且其設計的方式較設計DDOB 簡單與傳統運動控制器設計方式相同。

To improve the accuracy of motion systems, reduction of both tracking error and contouring error is necessary. In practice, performance of systems is often affected by disturbances such as loading and friction. This research is based on the integrated controller which reduces both the tracking error and contouring error. By applying digital disturbance observer (DDOB) to the integrated controller, the contouring error can be further reduced. Also, the stick-slip phenomenon due to friction is reduced by applying the DDOB. The robustness of the system can be preserved when the loading varies. Meanwhile, by adding an acceleration loop to the motion systems, the higher bandwidth of acceleration loop leads to reduction of model uncertainties. Thus, the tracking and contouring accuracy can be also improved. Results indicate that bandwidth of the present control systems is higher than those without the acceleration loop. Also, when the loading varies, the motion controller with an acceleration loop inside performs better. The design process of the controller with an acceleration loop is easier than the design process of DDOB and thus, the proposed controller becomes more practical for single-axis systems.