虛擬實境與六軸平台整合系統：力感呈現、操控、與實驗驗證

Abstract

現今，結合資訊、機電、控制等技術，發展一即時動態模擬系統以供高科技娛樂或模擬訓練用途已日趨成熟，而這樣的即時動態模擬系統主要包括：六軸運動平台、力操控器(搖桿)、虛擬實境互動場景、即時動態模擬單元和網路型系統控制及整合。虛擬實境是以電腦模擬產生一三度空間虛擬環境，人們可以身歷其境般置身於其中進行操作，就如同於真實世界一樣。在我們所發展的虛擬實境系統中，除了軟體顯示部分外，還有連接一六軸運動平台。六軸運動平台是一種平行結構操作器，其比傳統的三軸平台，或是傳統的串列式結構，具有更高的力重比，剛性與控制精度。此六軸運動平台是採用油壓比例伺服閥驅動系統，來達成運動平台在空間中做六自由度運動之目的，藉此可以模擬飛機、船舶、車輛等運動。本論文的研究目的是針對六軸平台與虛擬實境的系統整合中，另加入一具有2軸力回饋的力搖桿，探討力資訊在此整合系統中所扮演的角色，也就是說將探討當一操作者位於平台上，藉由力搖桿的力回饋資訊，將帶給操作者何種不同觸覺及視覺（虛擬實景）的力感。我們採用WorldToolKit的軟體來發展一釣魚相關的虛擬場景，並分析利用力搖桿所獲得的力資訊。實驗部分，我們讓操作者透過頭盔顯示器或投射螢幕上觀看在釣魚情況的虛擬場景，分別坐在地上的椅子及六軸平台上，使用有力回饋及無力回饋搖桿的不同方式操控場景中的釣竿，以比較其釣魚的力資訊、互動時間、得分情形、互動距離，以及操作者與魚互動的感受程度。分析結果顯示使用具有持續力資訊回饋的搖桿，在規律的動態平台變化中，可輔助操作者對調整場景力資訊的認知，增加操作者對虛擬場景互動的效果，更能沈浸在虛擬場景的活動中，相較於無持續力資訊回饋的搖桿，能提供更有逼真的感受。

Nowadays, to develop a real-time dynamical simulation system by integrating the technologies of information science, mechatronics, and control. This real-time dynamical simulation system consists of five elements follows 6-DOF (degree of freedom), joystick, interactive virtual reality, real-time simulation unit, and LAN (local area network)-based system integration and control. In this thesis, an integrated system consisting of a six-DOF motion platform and an accommodation of virtual reality has been developed. In addition, a two-DOF force reflection joystick is added to this arrangement to understand the role of force information performed in this VR-based motion platform integration system. In a word, a user can actually experience the force feeling through his haptic and visual scenes as he operates this system using the force reflection joystick. We employ the WorldToolKit software to develop a VR scene of fishing and to analyze the force information derived from the force reflection joystick. With respect to our experiment, it is designed that operators can view VR of the fishing situation via a projected screen or by wearing a HMD. The game can be proceeded by sitting in a chair on a six-DOF motion platform or on the ground, with or without the usage of force reflection from the joystick to be acting as a fishing rod. The factors acquired to be analyzed in the experiment include force information, interaction time, scores, with the fish distance of interaction. In experimental results indicate that operators manipulate the force reflection joystick can immersion the VR much more as compared with those using joystick without force reflection. Moreover, force feedback improves the cognition of the operator in maneuvering virtual, and the small VR scene change was well suited to used the force reflection joystick. Chinese Abstract i English Abstract ii Acknowledgements iii Contents iv List of Tables vi List of Figures vii 1 Introduction 1 2 A VR-Based Motion Platform System 6 2.1 Main Modules ……………… ……………………… 6 2.1.1 VR I/O devices …………………………………… 6 2.1.2 VR engine ………………………… …………… 9 2.1.3 Six-DOF motion platform ……………… … … 9 2.2 System Organization ……………………………… 13 3 Hardware Implementation 17 3.1 Force Reflection Joystick …………………………… 17 3.2 Six-DOF Motion Platform ………………………… 20 4 Software Implementation 28 4.1 3D Object Geometric Modeling …………………… 28 4.2 VR Programming for Simulation Management ……… 29 4.3 Communication Programming ……………………… 33 4.4 Dynamic Modeling for Objects and Environments …… 38 5 Experiment 41 5.1 Experimental Design ……………………………… 41 5.2 Experimental Results ……………………………… 45 6 Conclusion 51 6.1 Future Works ……………………………………… 51 Appendix: Mathematical Analysis for the Six-DOF Motion Platform A.1 Analysis of Inverse Kinematics …………………… 53 Bibliography 56