No abstract

Tactile internet" refers to a network that can support real-time interactions between human operators and remote cyber-physical systems as if they were near to each other. For this, the network should support ultra-low latency communication, often referred to as the 1ms challenge. However, we observe that network requirements, such as latency and bandwidth, of tactile internet based cyber-physical systems or Tactile Cyber-Physical Systems (TCPS) are not static: they severely fluctuate over time. Therefore, for TCPS, static provisioning of network resources is sub-optimal. For optimal utilization of network resources, we propose a mechanism to, per TCPS flow, dynamically create, destroy and switch network slices, based on the network resources needed at that time. Our solution consists of two main components. First, we develop a clustering algorithm to determine the slices and their specifications required to support a TCPS flow. Second, we leverage Software-Defined Networking (SDN) and P4-programmable switches to enable onthe-fly provisioning and switching of these slices.

Several on-body sensing and communication applications use electrodes in contact with the human body. Body–electrode interfaces in these cases act as a transducer, converting ionic current in the body to electronic current in the sensing and communication circuits and vice versa. An ideal body–electrode interface should have the characteristics of an electrical short, i.e., the transfer of ionic currents and electronic currents across the interface should happen without any hindrance. However, practical body–electrode interfaces often have definite impedances and potentials that hinder the free flow of currents, affecting the application’s performance. Minimizing the impact of body–electrode interfaces on the application’s performance requires one to understand the physics of such interfaces, how it distorts the signals passing through it, and how the interface-induced signal degradations affect the applications. Our work deals with reviewing these elements in the context of biopotential sensing and human body communication.

In this paper, we consider Tactile Cyber Physical Systems (TCPS), which differ from typical CPS in that haptic sensory feedback is included. In particular, we design and implement a TCPS testbed, called TCPSbed, using well-defined components and interfaces glued together using APIs. In addition to real connections, our testbed supports the interconnection of components over an NS3-emulated network. The testbed also supports the integration of applications that mimic the behaviour of real-world embedded objects. Since controlling latency and ensuring stability is crucial for TCPS applications, the testbed includes tools for fine-grained characterization of latency and control performance. Finally, through proof-of-concept experiments with our testbed, we demonstrate TCPSbed's capabilities to facilitate TCPS research and development.

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 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.Index Terms-quality of control, tactile internet, tactile cyberphysical systems.