| Virtual reality (VR) is an applied technique of computer, which emerged in 1960's and developed quickly in1990's. VR is a wide involving and complex technique that including computer graphics, interface of human and computer, interactivity of human and computer, artificial intelligence, psychology, 3-dimensional sound, and many subjects and techniques.VR has three main features: immersion, interaction and imagination. Immersion means the real degree which user feels when he exists in virtual environment. Interaction means the degree which user operates objects in virtual environment, and the degree which callback from virtual environment (including real time feature). Imagination means that VR is not only a medium, a senior user interface, but also reflects ideology of designer. Just because of the features of VR, it has widely applied in military science, medical science, education, culture, art and many fields.Aerial machinist VR training system is a scientific project for air force, which applied VR technique to daily training of new equipments. Firstly, we study any analysis the domestic and external available devices about VR. Then we determine the hardware system, which includes HMD, digital gloves, location system, main-control system, real time image system, 3D sound system, etc. HMD, digital gloves and location system are purchased from America. Main-control system, real time image system and 3D sound system are developed by us, which based on PC computer.First, real time image system produces 3D image of virtual aircraft cabin, ant outputs to HMD. Second, when user operates in system, location system detects positions of head and hands, digital gloves detect shapes of hands. The positions and shapes data are send to main-control computer. Third, main-control computer carries out the controls and calculations of collision detection and interaction of human and computer, and send data to real time image system and 3D sound system. At last, real time image system receives data from main-control computer, real time produces image of environment and send to HMD, in which status of the relevant objects have changed according to data from main-control computer. And 3D sound system also receives data from main-control computer, and plays relevant sounds and sends to HMD too.Software design of VR training system is the most important part. It is composed of 3D model building of system, main-control system, collision detection algorithm, real time image building system, 3D sound system.1. 3D model building of system is the first step of VR system. Except building virtual working environment, which is to build 3D virtual cabin environment. It should also build objects in virtual environment relevant to interaction, such as switches, throttles, meters, signals, and so on. Especially, it should build model of hand in virtual environment. In order to ensuring reality of virtual environment, all models are build according to real objects, and all grain pictures are come from real objects too. During building models, we use Levels of Detail technique for improving handling speed of real time image system.2. Main-control system is core of whole VR system. It coordinates and controls the working of each part. On the one hand, it connects with head location system, hands location system and digital gloves, to get position and shape data of head and hands. On the other hand, it also connects with real time image system and 3D sound system, to send data of head, hands and relevant objects. Main-control system is composed of data model construction, collision detection, script programming, and real time communication. The collision detection is a core technique of VR system. It receives status data from digital gloves, calculates position and shape data of hands. At the same time, use data model of objects in virtual environment, to judge if there is collision. 3.Collision detection is a core technique of system. As you know, there are some features about VR training system: a) Images displaying is not c...
|
PDF Full Text Request