Quality of Control Assessment for Tactile Internet based Cyber-Physical Systems

TL;DR

This paper introduces a new methodology and metric for evaluating the quality of control in Tactile Internet-based Cyber-Physical Systems, linking control stability to user cybersickness through experiments on various network setups.

Contribution

It develops a control-theoretic step response analysis method and a QoC metric to assess control stability and cybersickness in TCPS, validated through extensive experiments.

Findings

QoC metric is sensitive to control loop instabilities.

QoC effectively predicts cybersickness levels.

Methodology is validated across diverse network conditions.

Abstract

We evolve a methodology and define a metric to evaluate Tactile Internet based Cyber-Physical Systems or Tactile Cyber-Physical Systems (TCPS). Towards this goal, we adopt the step response analysis, a well-known control-theoretic method. The adoption includes replacing the human operator (or master) with a controller with known characteristics and analyzing its response to slave side step disturbances. The resulting step response curves demonstrate that the \textit{Quality of Control} (QoC) metric is sensitive to control loop instabilities and serves as a good indicator of cybersickness experienced by human operators. We demonstrate the efficacy of the proposed methodology and metric through experiments on a TCPS testbed. The experiments include assessing the suitability of several access technologies, intercontinental links, network topologies, network traffic conditions and testbed configurations. Further, we validate our claim of using QoC to predict and quantify cybersickness through experiments on a teleoperation setup built using Mininet and VREP.