A wearable sensor network is developed to track the human joint motion with high accuracy. One sensor unit consists of an accelerometer and a miniature linear sensor. We design one motion-based interface based on the wearable sensor network, in which users can control the virtual characters in both a video game and an online virtual environment (Second Life) by moving their wrists and knees. Based on the analysis of the situation awareness and the failure of task during the game playing, the results of the task performance on controlling the virtual characters indicated that the motion-based interface provided better control than the keyboard interface.otion capture technology has been broadly applied in entertainment, robotics, manufacturing, virtual environments (VEs) and other fields. In computer graphics relevant areas, motion capture technology is mainly used for view control, navigation, object selection or manipulation, and character animation [13]. The powerful, interactive, and immersive VEs typically require a tracker to manipulate and interact with the graphical objects [3]. In recent years, the motion track systems for the interaction in VEs and entertainments are becoming easier to use and cost effective.Motion tracking systems can be mainly categorized into ten categories: optical, imaged-based, mechanical, magnetic, inertial, acoustic, conductive fibers, inductive fiber mesh, optical fiber loss, and piezo-resistive fabric. Among them, inertial motion capture system comprising accelerometers and gyroscopes offers the relatively better performance since it has very low latency, can be measured at high rates, and has no sensitivity to interfering electromagnetic fields or ambient noises. The weaknesses of the inertial motioncapture system, however, are its electronic offsets and drift which yield significant tracking errors. The inertial tracker alone cannot recover reliably from these errors without introducing external reference information.Motion tracking based on sensor fusion of accelerometers, magnetometers, and gyroscopes [2][16] is one approach to solve the problems. In this approach, the orientations can be measured solely relying upon
