title: Robust Stability of Scaled-Four-Channel Teleoperation with Internet Time-Varying Delays.
abstract: We describe the application of a generic stability framework for a teleoperation system under time-varying delay conditions, as addressed in a previous work, to a scaled-four-channel (γ-4C) control scheme. Described is how varying delays are dealt with by means of dynamic encapsulation, giving rise to mu-test conditions for robust stability and offering an appealing frequency technique to deal with the stability robustness of the architecture. We discuss ideal transparency problems and we adapt classical solutions so that controllers are proper, without single or double differentiators, and thus avoid the negative effects of noise. The control scheme was fine-tuned and tested for complete stability to zero of the whole state, while seeking a practical solution to the trade-off between stability and transparency in the Internet-based teleoperation. These ideas were tested on an Internet-based application with two Omni devices at remote laboratory locations via simulations and real remote experiments that achieved robust stability, while performing well in terms of position synchronization and force transparency.
authors.affiliation: School of Industrial Engineering, University of Vigo, 36310 Vigo, Spain. emmad@uvigo.es.
authors.forename: Emma
authors.initials: E
authors.lastname: Delgado
authors.affiliation: School of Industrial Engineering, University of Vigo, 36310 Vigo, Spain. abarreiro@uvigo.es.
authors.forename: Antonio
authors.initials: A
authors.lastname: Barreiro
authors.affiliation: School of Industrial Engineering, University of Vigo, 36310 Vigo, Spain. pfalcon@uvigo.es.
authors.forename: Pablo
authors.initials: P
authors.lastname: Falcón
authors.affiliation: School of Computer Engineering, University of Vigo, 32004 Orense, Spain. mcacho@uvigo.es.
authors.forename: Miguel
authors.initials: M
authors.lastname: Díaz-Cacho
keywords: robust stability; teleoperation; time-varying delays; transparency