Transparency in Port-Hamiltonian-Based Telemanipulation

After stability, transparency is the major issue in the design of a telemanipulation system. In this paper, we exploit the behavioral approach in order to provide an index for the evaluation of transparency in port-Hamiltonian-based teleoperators. Furthermore, we provide a transparency analysis of packet switching scattering-based communication channels

Position Drift Compensation in Port-Hamiltonian Based Telemanipulation

Passivity based bilateral telemanipulation schemes are often subject to a position drift between master and slave if the communication channel is implemented using scattering variables. The magnitude of this position mismatch can be significant during interaction tasks. In this paper we propose a passivity preserving scheme for compensating the position drift arising during contact tasks in port-Hamiltonian based telemanipulation improving the kinematic perception of the remote environment felt by the human operato

Sampled data systems passivity and discrete port-Hamiltonian systems

In this paper, we present a novel way to approach the interconnection of a continuous and a discrete time physical system first presented in [1][2] [3]. This is done in a way which preserves passivity of the coupled system independently of the sampling time T. This strategy can be used both in the field of telemanipulation, for the implementation of a passive master/slave system on a digital transmission line with varying time delays and possible loss of packets (e.g., the Internet), and in the field of haptics, where the virtual environment should `feel¿ like a physical equivalent system

Port-contact systems in bilateral telemanipulation

In this paper we develop one of the first control applications of the recently proposed port-contact framework. We show how it is possible to model and control a bilateral telemanipulation system using port-contact systems and we develop a port-contact impedance controller that allows to impose a desired interactive behavior and a zero steady state position error during contact tasks

Spatially: Resolved heterogeneous dynamics in a strong colloidal gel

We re-examine the classical problem of irreversible colloid aggregation, showing that the application of Digital Fourier Imaging (DFI), a class of optical correlation methods that combine the power of light scattering and imaging, allows one to pick out novel useful evidence concerning the restructuring processes taking place in a strong colloidal gel. In particular, the spatially-resolved displacement fields provided by DFI strongly suggest that the temporally-intermittent local rearrangements taking place in the course of gel ageing are characterized by very long-ranged spatial correlations

Biopolymer gels with "physical" cross-links: gelation kinetics, aging, heterogeneous dynamics, and macroscopic mechanical properties

Alginate is a natural biopolymer that forms, in the presence of divalent cations, ionic-bound gels typifying a large class of biological gels stabilized by non-covalent cross-links, and displaying a consistent restructuring kinetics. We investigate the kinetics of formation and aging of alginate gels by slow permeation of a curing CaCl2 agent by means of photon correlation imaging, a novel optical technique that allows obtaining the microscopic dynamics of the sample, while retaining at the same time the spatial resolution of imaging techniques. Specifically, the gelling kinetics displays a peculiar non-diffusive behavior, and the subsequent restructuring of the gel structure shares several features in common with the aging of colloidal gels, in particular for what concerns the occurrence of heterogeneous dynamics effects. A comparative analysis of the gel macroscopic mechanical properties at different aging stages further highlights distinctive effects arising from the non-permanent nature of the bonds

Bridging the gap between passivity and transparency

In this paper a structure will be given which in a remarkably simple way offers a solution to the implementation of different telemanipulation schemes for discrete time varying delays by preserving passivity and allowing the highest trans- parency possible. This is achieved by splitting the communication channel in two separate ones, one for the energy balance which will ensure passivity and one for the haptic information between master and slave and which will address transparency. The authors believe that this structure is the most general up to date which preserves passivity under discrete time varying delays allowing different control schemes to address transparency