在本論文的研究中，我們提出了力回饋的修正 (force-feedback refinement) 與觸力的展現 (force rendering) 技術應用於我們所發展的虛擬觸覺系統中。由於研究經費的限制，我們所使用的力回饋器有些粗糙，操作會感覺到許多阻力因而影響到力回饋與觸覺表現的逼真度。因此在本研究中，我們提出力回饋的修正方法 (force-feedback refinement) 來消除這些阻力，目的就是要讓使用者感覺到他們在操作一個無阻力的器具；另一方面，我們也提出展現力道與觸感的方法 (force rendering)，讓使用者可以感覺到虛擬環境中物體的形狀及其表面的特性，例如摩擦力 (friction) 及紋理的特性 (texture)。為了要增進展現效率，我們採用一個快速的碰撞偵測方法，可以有效的提高視覺展現的速度 (frame rate)；另外，為了要讓觸覺的感受更加平順，我們也採用多執行緒 (multi-thread) 的方法，提高觸覺回饋的頻率 (haptic servo rate)。在我們所建構的虛擬環境中，使用者可以即時 (real time) 的看到及感觸到虛擬的物體。 In this paper, we develop two techniques: force feedback refinement and force rendering for our virtual haptic system. Due to the limitation of research budget, our surgical instruments are coarse and involve undesired forces. The force feedback refinement technique is just proposed to eliminate the undesired forces such that users can feel as if they control frictionless and weightless instruments. On the other hand, the force rendering technique is proposed to display the force feeling on surface details such as the shape of an object, the friction force of the object, and the texture property of the object. To improve the rendering performance, a fast collision detection algorithm is adopted to speed up the process of force rendering and a multi-thread technique is employed to increase the haptic servo rate. Based on the proposed haptic system, users can interact with virtual environments and have realistic haptic feeling of virtual objects in real time.
