Tham khảo tài liệu 'human-robot interaction part 14', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | Capturing and Training Motor Skills 241 Virtual reality platform The virtual environment platform provides the visual information to the user was programmed in XVR. There are 3 different sequences involved in this scenery. The first one is the initial screen that shows 5 avatars executing different Tai Chi movements. When a user tries to imitate one movement the system recognizes the movement through the gesture recognition algorithm and passes the control to the second stage called training session . In this part the system visualizes 2 avatars one represents the master and the other one is the user. Because learning strategy is based on the imitation process the master performs the movement one step forward to the user. The teacher avatar remains in the state n 1 until the user has reached or performed the actual state n. With this strategy the master gives the future movement to the user and the user tries to reach him. Moreover the graphics displays a virtual energy line between the hands of the user. The intensity of this line is changing proportionally depending on the error produced by the distance between the hands of the student. When a certain number of repetitions have been performed the system finishes the training stage and displays a replay session that shows all the movements performed by the student and the statistical information of the movement s performance. Figure 12 shows the storyboard for the interaction with the user and Figure 13 A B shows the virtual Tai-Chi environment. Fig. 13. VR environment A Initial Screen 5 avatars performing Tai-Chi movements B Training session two avatars one is the master and second is the user. C Distance of the Hands D Right Hand Position. Vibrotactile feedback system The SHAKE device was used to obtain wireless feedback vibrotactile stimulation. This device contains a small motor that produces vibrations at different frequencies. In this process the descriptor obtains the information of the distance
