史都華平台偏移點之運動校正

The Motion Calibration for an Offset Point on the Stewart Platform

林信宏(Hsin-Hom Lin)

指導教授 ： 曾百由

國立臺北科技大學/機電學院/自動化科技研究所/碩士(2006年)

摘要

一般對史都華平台的運動控制多是給定活動平台中心點的六個自由度，並用逆向運動學公式推導求出致動器相對應長度，對於活動平台上架設儀器所產生位置偏移的影響則未見深入而有效的探討。本研究主要針對上平台中心點的偏移量做運動的量測，並配合六軸平台運動的量測，探討位置偏移的影響與可能的補償方式。研究的結果可應用在於常見的動感模擬器與震動模擬器中。因為在偏移的位置所表現的運動會不同於給定活動平台中心點的命令，為了克服額外的運動，研究中將使用空間座標轉換方程式來計算與執行動感模擬的補償。此方法也可以應用在震動模擬的應用上，當模擬裝置的安裝位置跟上平台中心點產生一相對誤差，而使得對模擬裝置的震動模擬也會有誤差產生，在本研究中也運用空間座標轉換方程式計算補償運動並驗證其結果。
實驗過程以數位訊號處理器(DSP)為史都華平台運動控制器，上平台架設儀器量測運動資料並以量測位置為偏移點。藉由推導空間座標轉換方程式作為運動補償計算的方法，規劃完史都華平台的運動路徑後，以未補償運動的理論數據與實際量測的運動資料作比較，驗證理論計算與量測方法的正確性並進行補償運動的加速度量測。研究並將此運動補償的成果運用在一套伺服馬達角度定位控制上，比較運動補償前後對馬達定位控制的差異性，藉以證實空間座標轉換對平台偏移點運動補償的效果。

關鍵字

史都華平台 ； DSP ； 空間座標轉換

並列摘要

Generally, the motion of Stewart platform is commanded with the center of the mobile plate; the lengths of actuators are then derived with inverse kinematics. However, studies of the motion of an offset point on the Stewart platform and its calibration have not been found. This research has measured the motion of the offset point, as well as the motion of the mobile plate of the Stewart platform, to investigate the effects of offset and means to reduce its affection. The result of this study could be applied to motion simulator or vibration simulation machine. Because the motion of offset points would be different from what has been commanded to the center of the mobile platform, this research will apply the spatial coordinate transformation to calculate and calibrate the additional motions due to the offset. This concept could also be applied to calibrate the vibration simulation. When there is offset between the testing device and the center of the mobile plate, there must be error in the simulated vibration. This research will utilize the fore-mentioned spatial coordinate transformation to calibrate motion and verify its results.
The experiment in this research has adopted the Digital Signal Processor (DSP) as the Stewart platform motion controller to control the motion of an offset point above the mobile plate. By using the spatial coordinate transformation, motion of the Stewart platform will be arranged and measured to compare and validate the results with and without the motion calibration. A servo-motor driven motion stabilizer will be implemented to test and analyze the effects of the motion calibration to validate results of the calibrating method derived in this research.

並列關鍵字

Stewart Platform ； DSP ； Spatial Coordinate Transformation

參考文獻

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