| Research Abstract |
Owing to recent advance of communication networks, it is now becoming realistic to transmit not only conventional media like voice and images but also other streaming media as haptic information. This is a very challenging task and a few experimental result of the usage of haptic information over networks have been proposed. Since almost all the researches were by the community of researchers on robotics, they "innocently" ignored the delay, jitter and packet loss. Namely, they treated the network as ideal. However, the real networks are far from ideal and network impairment causes the heavy deteriation of Quality of Services (QoS) on haptic application. From this viewpoint, we study the effect of network impairment, especially delay, jitter and packet loss, on the haptics collaboration on Internet. For example, we found that delay of 100 [msec] is very crucial in haptic collaboration and if it is more than 100 [msec.], we cannot maintain good QoS in any way. Then, based on them, several countermeasures against such impairment were proposed. Against packet loss, we proposed a practical dead-reckoning method. Against, the limitation of bandwidth, we proposed a bandwidth compression method based on dead-reckoning and the 2nd order prediction. Against jitter, we first proposed a practical intra-media synchronization mechanism. We also proposed an inter-media synchronization mechanism. Finally, we integrated the above mentioned countermeasure into one practical system. It is very and robust and happily, it is now becoming widely used as the de-fact of the countermeasure against network impairment on networked haptic collaboration systems.
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