Telerobotics over IP networks: Towards a low-level real-time architecture

Abstract

Long distance teleoperation over asynchronous transmission links makes many classical teleoperation schemes unstable. The use of this kind of media involves varying transmission delays that may become prohibitive even at short distance. However, they are standardized, cheap and widespread over the planet. This paper presents our latest works on the improvement of teleoperation loops, by providing a low-level architecture which permits the use of classical teleoperation controls over asynchronous digital links.

Time-Delay Estimation and Finite-Spectrum Assignment for Control Over Multi-Hop WSN

“…Experimental results on telerobotics over TCP/IP networks illustrate the importance of varying transmission delays in the control loop [4], where the authors combine a generic estimation/prediction control scheme with a buffering of the received packets, which compensates for the delays jitter. While the buffer may decrease the transient performances of the closed-loop system [5], this work motivates the use of estimation/prediction schemes to achieve robust and efficient control over networks.…”

Control of a remote system over network including delays and packet dropout

“…To bypass this problem, it was proposed by Lelevé et al [1999Lelevé et al [ , 2001, N.J. Ploplys and Alleyne [2004] to introduce two input buffers (Master and Slave) that make both of the receivers wait until the maximum value h M of the communicaton delay is reached. However, it is obvious that this situation maximizes the delays h 1 (t) and h 2 (t) up to their worst (largest) value (i.e., h 1 (t) ֒→ h M and h 2 (t) ֒→ h M ) and, consequently, decreases the possible range of speed performance.…”

A gain scheduling strategy for the control and estimation of a remote robot via Internet

“…Because of this lack of knowledge, predictor-based control laws (E. Witrant et al, 2007) cannot be applied. A delay maximizing strategy (J.P. Richard, 2003;A. Lelevé et al, 2001) ("virtual delay", "buffer", or "waiting" strategy) can be carried out so to make the delay constant and known.…”