六連桿平行滑動機之運動控制系統

Abstract

本論文首先對平行式操縱機與串接式操縱機作特性上之比較，分析平行式操縱機之優點，並回顧相關研究文獻，接著我們提出六連桿平行滑動機(Hexaglide)逆向運動學分析,並推導出其逆向運動學計算公式。如此可求得運動平台不同姿態時六個線性馬達之位置。經由動力學分析，我們計算出平台運動時六連桿所需的施力,並導出Hexaglide動態方程式。在運動控制部分，若是能將六個馬達位置命令同步分別由伺服控制器執行，則可以簡單之單一輸入單一輸出(SISO)之線性控制設計來實現Hexaglide之運動控制。因此在進行控制時可將每個馬達視為獨立的系統，用六個控制器分別控制六個馬達達到所要的位置，如此可使平台到達給定的位置與角度。在給定機構幾何參數等條件下，我們以電腦模擬初步驗證了所提出之設計。模擬平台對X,Y,Z軸平移及旋轉時六個線性馬達相對應的位移變化及六連桿所受的施力變化。由於Hexaglide之動態方程式參數隨平台與馬達位置不同而變化，因此我們提出以模式參考適應控制(MRAC)方法來設計控制器，論文中以電腦模擬平台作直線，旋轉及圓周路徑的追蹤控制。模式參考適應控制方法可隨系統變化而調整其控制參數，因此比固定參數PID控制器有更精確的追蹤響應，尤其是有外力干擾時可即時調整控制參數，使其響應幾乎不受影響。另為了改善模式參考適應控制器的暫態振盪現象，我們加入了PD控制器做平行補償來降低暫態振盪現象。模擬結果顯示，所提出之PD與MRAC整合之控制器具有較佳之追蹤控制結果。最後我們研製三軸平行滑動機，以旋轉馬達結合導螺桿將旋轉運動轉換成直線運動，來驗證馬達位置命令同步分別由伺服控制器執行，則可以簡單之單一輸入單一輸出(SISO)之線性控制設計來實現三軸平行滑動機之運動控制。

In this thesis,we present the research results of the development of Hexaglide motion controll system. The inverse kinematics analysis of Hexaglide is presented. An algorithm is proposed to compute the motor positions when the position and orientation of the platform are given. The dynamics equations of the Hexaglide are derived. The relation between platform motion and the link force can be computed accordingly. Computer simulations are presented to verify the proposed methods. An independent single-input-single-output (SISO) control architecture is developed for 6-DOF Hexaglide. However, adaptive control schemes are required to improve the tracking performance. A model reference adaptive control(MRAC) approach is adopted in this thesis for this purpose. In order to improve transient performance of the MRAC,a PD controller is added to combine with the conventional adaptive controller. Simulation results confirm that the proposed controller has satisfactory tracking performance. A three DOF triglide system has been designed and implemented. Rotary motors and ball screws we used to achieve linear motion on the linear glide. Experimental results of this mechanism are demonstrated.