虛擬實境系統力回饋操控器之研製與實驗

Abstract

近年來由於電腦及人機界面設備的快速發展，使得虛擬實境 (VR) 得以大量應用於娛樂、教育、訓練、工業、藝術等各方面，VR系統透過視覺、聽覺、及觸覺等感官途徑與使用者產生即時互動，使其擁有身歷其境的擬真感受，其中產生觸覺的力回饋裝置對提昇真實感及即時互動的幫助很大。本論文即研製一同時具有方向盤式及搖桿式優點的兩軸力回饋操控器，供操作者輸入命令及提供操作者場景力資訊，我們所發展的力回饋裝置以力矩控制馬達、驅動器、控制卡、本體的機械裝置、以及控制器所組成，控制器為一部個人電腦，用以模擬視覺與觸覺的VR場景，並且能以多執行緒的方法產生不同的影像及力更新頻率；我們設計一系列的實驗，分析力回饋操控器的力更新頻率對觸覺品質之影響，以及探討如何擷取適當的場景資訊轉換成力形式呈現給操作者。由實驗得知，對可接受的觸覺品質，其所需的最低力更新頻率隨著操作模式而有所不同，越高的力更新頻率提供較佳的觸覺品質，但需要較高的運算能力，而擷取適當的場景資訊轉換成適當的力形式呈現，將有助於操作者即時掌握系統動態，進而提高工作效能。

Along with the development of computers and human-machine interface devices in recent years, VR has been popularly used in many areas, e.g., entertainment, education, training, industry, arts, and so on. VR can yield the operator an illusion of reality and a feeling of “being there” via real-time interaction with the operator through many different sensorial channels, such as vision, audition, and haptics. Specifically, force feedback devices can provide much reality and real-time interaction. In this thesis, we develop a 2-DOF force-feedback manipulator that lets the operator input commands and sense force information. The force-feedback manipulator consists of torque-controlled motors, drivers, controller cards, manipulator mechanism, and a controller unit. The controller unit is a PC, which emulates VR scenes, and generates graphics and force in different fresh rates using the multi-threading technique. We design a series of experiments, to investigate the relationship between the force update frequency and the haptic quality, and to extract suitable information from the VR scenes and express them in the form of force. From the results of our experiments, the minimum force update frequency for the acceptable haptic quality depends on the operating mode. And higher force update frequency provides higher haptic quality at the expense of computation load. Suitable force representation derived from the information from VR scenes makes the operator well deal with system dynamics in real-time, and consequently enhance performance.