虛擬實境即時船舶動態模擬系統之場景與模型建立

Abstract

海洋是一個變化無常的環境，有時風平浪靜、有時卻是狂風駭浪，在其上航行往往隱藏著無數的危險。所以本文將在虛擬實境的系統上，研究即時船舶動態模擬訓練系統。在此我們將適當建立周圍海浪的動態模型，並提出新的船舶動態模擬理論推導與方法，探討船舶在動態海域上航行時與海浪的各種受力情形，來模擬航行於波濤洶湧海洋的船舶其六自由度變化情形。在動態海域的模擬上，我們係根據長形波公式和細碎公式來作結合，推導其數學模型，提供給整個即時動態模擬訓練系統一個動態的環境。在船舶動態物理模型的建立上，我們根據所建立的動態海域，以流體力學的觀點來計算船舶於海洋上航行時的力和力矩。 在系統整合部份，本文提出虛擬實境場景底層的軟體架構，使用Windows 2000作業系統所提供的Shared Memory、Socket、FILE等各種通訊介面來作為各個獨立模組的通訊管道，而我們可以增添/刪減任何的通訊介面模組來滿足對場景功能的要求，也可以降低場景主體程式所需要的修改。本文並利用TCP/IP網路連線功能來與六軸運動平台 控制器作連結，採用位置控制和沖淡演算(Washout)控制兩種方式在平台上模擬船舶的六軸姿態和力的表現。另外並對網路的傳輸模組採用Real-time的設計機制，介紹整個即時機制的設計方法和流程，以及對整個即時船舶動態模擬訓練系統作分析與討論。最後將虛擬實境場景、即時動態模擬模組、六軸運動平台、力操控搖桿 整合成為一完整之即時船舶動態模擬訓練系統。

The ocean is a dynamic changing environment. Sometimes it is calm and tranquil, while sometimes it may become violent due to strong wind and rain. Hence, a boat sailing on the real ocean may be very dangerous. To avoid danger in the real world when training the skills for safe manipulation and control of sailing, in this thesis we shall develop a motion simulation of sailing training system with real-time dynamic model on virtual reality. We shall properly construct the dynamic simulation environment of ocean waves and probe into the real force situation when sailing on the dynamic simulation of waves. Finally, we propose a new theory and method for dynamic simulation module of sailing. In the simulation of dynamic ocean waves, we integrate the mathematic model of long-crested wave theory and broken-bits wave theory for the fast generation of dynamic ocean environment for the training system. In the method to produce the real force feeling of sailing, we base on hydrodynamics to calculate real force and torque from the generated dynamic waves. In system integration, we bring the VR scene、dynamic module、washout filter theory、Stewart platform and force-feedback joystick into an integrated sailing training system based on real-time software framework and network communication. We use Share Memory、PC Socket、 File Processing functionality from Microsoft Windows 2000 Operating System to develop the previous proposed software framework and other communication modules. For network communication, we use TCP/IP as the interface between VR scene and Stewart platform, using position control and washout filter module to perform the 6-DOF posture of platform and the feeling of force. We shall also introduce the real-time module under Windows 2000, and use it to analyze and explore the real-time problems in the dynamic ship training system. Because of these independent modules, we can not only increase the expansibility of the sailing training system but also change the configuration dynamicall