Bilateral teleoperation through Internet

The implementation of a reliable bilateral teleoperation, when the Internet is used for data exchange, is a complex task, this due to the time-varying characteristics of the communication link, in terms of delay, throughput and reliability. Most of the reported studies on Internet-based teleoperation address the problems of the variable delay and packet losses. We analyze the most recent results in this field and present a pair of results on the control law design, the first based on an extension of the Generalized Predictive Control to bilateral telerobots, and the second relying on the new concept of the “communication disturbance observer” (CDOB). Such techniques have been successfully used in both long and short distance bilateral teleoperation. Additionally, we address the problem of using Internet when the same connection is shared by both hard real time (e.g. haptic) and non-hard real time (e.g. audio and video) data flows, in a realistic scenario, with variable operating conditions. We present a simple policy for adaptive data flow management that has been applied when video and haptic data are transmitted between slave and master station in a bilateral telerobotic device. The proposed solution is based on off-line and on-line measurements on the Internet connection and a properly designed adaptation scheme, which trims the packet size of a buffered H-263 video flow.