臺灣博碩士論文加值系統

隨著電腦圖學技術的快速發展，越來越多彈性以及動作自然度極高的虛擬角色動作在遊戲以及動畫這些領域出現。本研究從來源檔案中擷取虛擬角色的骨架與動作資訊，利用開放動態物理引擎(Open Dynamics Engine)中的函式功能建置骨架中包含物理屬性的虛擬角色，其目的藉由物理引擎來調整動作資料庫的動作，使動作能夠順暢且具合理地在新的環境中執行。本研究使用PD控制器(Proportional-Derivative controller)追蹤來源檔案中的角色動作。PD控制器的作用是使虛擬角色所模擬的動作接近來源檔案中的角色動作。計算方式是將當前虛擬角色與來源檔案的角色對其關節角度與關節速度值做比較，接著計算虛擬角色追蹤來源檔案動作的力矩。除了考慮參數上的設定之外，平衡性也是考量的重要因素，傳統上的平衡大部分採用零力矩點(zero- moment point)的運算，而本研究透過髖關節以及骨盆等控制質心，並利用腳踝的關節部分傳輸地面接觸力來進行力矩的修正。虛擬角色受外力干擾的情形，本研究會將平衡與動作追蹤控制的部分做三個部份的探討，這方面不同於直接從動作資料庫中取得動作的方法，實驗中會藉由參數上的調整來產生較為自然的動作。

With the rapid growth of computer graphics, plausible and natural motions of animating 3D characters are more desirable when we accomplish computer games and animations. The up-to-date approach is to apply physically based methods to control and simulate character motions. In this paper, we take advantage of both motion tracking and balance control techniques to allow a bipedal character to react to different disturbances by the proposed motion coordination control. In the first step, we apply Open Dynamics Engine to be served as the physics engine for creating a 3D character with fully physical parameters in terms of a few reference motions. The next step is to employ Proportional-Derivative controller to follow a particular reference motion as closely as possible. Besides, we take the standing balance control into account to let the character adapt to external forces and ground contacts. In the case of suffering from slight perturbations, it is a trade-off problem in which we simultaneously make use of the motion tracking and balance control. We devise a motion coordination control to solve the above problem and try to apply more joint torque to adjust character motions accordingly. In the experiments, we test different extents of external forces to demonstrate the effectiveness of the three major balancing modes, including basic, hold, and stagger. The results show that the reactive motion of the character is robust and intuitive while pushing and pulling under the acceptable conditions.

目錄
中文摘要 i
Abstract ii
目錄 iv
表目錄 v
圖目錄 vii
第一章、 緒論(Introduction) 1
1.1 研究動機 1
1.2 研究方法 2
1.3 章節安排 3
第二章、相關工作(Related Works) 4
2.1平衡控制 5
2.2二足控制器 6
2.3資料驅動 7
2.4機器人學的延伸 9
第三章、系統架構與角色狀態同步化(System Structure and Character State Synchronization) 11
3.1 虛擬角色設定步驟 11
3.2 系統架構 13
3.3基本狀態判斷 14
3.4受力狀態判斷 16
3.5動作切換狀態判斷 18
第四章、動作追蹤與平衡控制(Motion Tracking and Balance Control) 19
4.1 動作追蹤 19
4.2 平衡架構設計 22
4.3 動作回饋調整 24
4.3.1 跨步機制 25
4.3.2 例外處理 27
第五章、動作協調控制(Motion Coordination Control) 29
5.1 動態來源參數調整 30
5.2 三階段受力判斷 31
第六章、實驗結果 (Experimental Results) 34
6.1 虛擬角色基本設定 35
6.2 虛擬角色模擬來源動作 39
6.3 虛擬角色受力結果 40
第七章、結論與未來方向 (Conclusions and Future Work) 45
參考文獻 47

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