A compact two-phase twisted string actuation system: Modeling and validation

The preliminary experimental study toward the implementation of an arm rehabilitation device based on a twisted string actuation module is presented. The actuation module is characterized by an integrated force sensor based on optoelectronic components. The adopted actuation system can be used for a wide set of robotic applications and is particularly suited for very compact, light-weight, and wearable robotic devices, such as wearable rehabilitation systems and exoskeletons. Thorough presentation and description of the proposed actuation module as well as the basic force sensor working principle are illustrated and discussed. A conceptual design of a wearable arm assistive system based on the proposed actuation module is presented. Moreover, the actuation module has been used in a simple assistive application, in which surface-electromyography signals are used to detect muscle activity of the user wearing the system and to regulate the support action provided to the user to reduce his effort, showing in this way the effectiveness of the approach.

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The Impact of Modeling Complexity and Two-Phase Flow Parameters on the Accuracy of System Modeling for Unitary Air Conditioners

HVAC&R Research ◽

10.1080/10789669.2004.10391087 ◽

2004 ◽

Vol 10 (1) ◽

pp. 5-20 ◽

Cited By ~ 8

Author(s):

Todd Harms ◽

James Braun ◽

Eckhard Groll

Keyword(s):

Two Phase Flow ◽

System Modeling ◽

Phase Flow ◽

Two Phase ◽

Air Conditioners ◽

Flow Parameters ◽

The Impact

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Traveling Waves Solutions of a Convective–Dispersive System Modeling Two-Phase Fluid Flows

Mathematical Models and Methods in Applied Sciences ◽

10.1142/s0218202597000451 ◽

1997 ◽

Vol 07 (07) ◽

pp. 887-908 ◽

Cited By ~ 1

Author(s):

Nabil Bedjaoui

Keyword(s):

Fluid Flow ◽

Solitary Waves ◽

Traveling Waves ◽

System Modeling ◽

Fluid Flows ◽

Two Phase ◽

Periodic Traveling Waves ◽

Dispersive System ◽

Phase Fluid

In this paper we are interested in the existence of traveling waves for a convective dispersive system modeling a stratified two-phase fluid flow in horizontal ducts. We prove the existence of a class of nonconstant solitary waves and periodic traveling waves.

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A Singular Perturbation Approach for Modeling Differential-Algebraic Systems

Journal of Dynamic Systems Measurement and Control ◽

10.1115/1.2801500 ◽

1998 ◽

Vol 120 (4) ◽

pp. 541-545 ◽

Cited By ~ 20

Author(s):

Brandon W. Gordon ◽

Sheng Liu

Keyword(s):

Singular Perturbation ◽

State Space ◽

System Modeling ◽

Space Representation ◽

Perturbation Approach ◽

Algebraic Equations ◽

Two Phase ◽

Modeling And Analysis ◽

State Space Representation ◽

Singular Perturbation Analysis

Dynamic systems described by an implicit mixed set of Differential and Algebraic Equations (DAEs) are often encountered in control system modeling and analysis due to inherent constraints in the system. A key difficulty in control and simulation of DAE systems is that they are not expressed in an explicit state space representation. This paper describes a general approach based on singular perturbation analysis for adding fast dynamics to a system of DAEs so that they can be expressed in an explicit state space form. Conditions for asymptotic convergence and approximation methods are investigated. The approach is illustrated for a model of a two-phase flow heat exchanger.

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