Feasibility Study of a Hand Exoskeleton for Rehabilitation of Post-Stroke Patients

2012 ◽  
Author(s):  
Marco Troncossi ◽  
Mohammad Mozaffari Foumashi ◽  
Marco Carricato ◽  
Vincenzo Parenti Castelli
Keyword(s):  
Feasibility Study ◽  
Degrees Of Freedom ◽  
Degree Of Freedom ◽  
Design Issues ◽  
Stroke Patients ◽  
Two Degrees Of Freedom ◽  
Kinematic Chains ◽  
Basic Module ◽  
Post Stroke ◽  
Hand Exoskeleton

This paper illustrates the activity done by the authors for the development of a hand exoskeleton with two degrees of freedom addressed to the rehabilitation of post-stroke patients. The literature is investigated and many design issues are deeply discussed with the purpose to provide a reader who is approaching this problem with useful guidelines. The feasibility study of a one degree of freedom mechanism for one finger, intended as the basic module of the targeted hand exoskeleton, is outlined: two kinematic chains having six and eight links respectively are presented and discussed.

Strouhal Number for VIV Excitation of Long Slender Structures

2018 ◽  
Author(s):  
Andrew E. Potts ◽  
Douglas A. Potts ◽  
Hayden Marcollo ◽  
Kanishka Jayasinghe
Keyword(s):  
Reynolds Number ◽  
Strouhal Number ◽  
Degrees Of Freedom ◽  
Measurement Techniques ◽  
Cross Flow ◽  
Degree Of Freedom ◽  
Circular Cylinders ◽  
Two Degrees Of Freedom ◽  
Shedding Frequency ◽  
Eddy Shedding

The prediction of Vortex-Induced Vibration (VIV) of cylinders under fluid flow conditions depends upon the eddy shedding frequency, conventionally described by the Strouhal Number. The most commonly cited relationship between Strouhal Number and Reynolds Number for circular cylinders was developed by Lienhard [1], whereby the Strouhal Number exhibits a consistent narrow band of about 0.2 (conventional across the sub-critical Re range), with a pronounced hump peaking at about 0.5 within the critical flow regime. The source data underlying this relationship is re-examined, wherein it was found to be predominantly associated with eddy shedding frequency about fixed or stationary cylinders. The pronounced hump appears to be an artefact of the measurement techniques employed by various investigators to detect eddy-shedding frequency in the wake of the cylinder. A variety of contemporary test data for elastically mounted cylinders, with freedom to oscillate under one degree of freedom (i.e. cross flow) and two degrees of freedom (i.e. cross flow and in-line) were evaluated and compared against the conventional Strouhal Number relationship. It is well established for VIV that the eddy shedding frequency will synchronise with the near resonant motions of a dynamically oscillating cylinder, such that the resultant bandwidth of lock-in exhibits a wider range of effective Strouhal Numbers than that reflected in the narrow-banded relationship about a mean of 0.2. However, whilst cylinders oscillating under one degree of freedom exhibit a mean Strouhal Number of 0.2 consistent with fixed/stationary cylinders, cylinders with two degrees of freedom exhibit a much lower mean Strouhal Number of around 0.14–0.15. Data supports the relationship that Strouhal Number does slightly diminish with increasing Reynolds Number. For oscillating cylinders, the bandwidth about the mean Strouhal Number value appears to remain largely consistent. For many practical structures in the marine environment subject to VIV excitation, such as long span, slender risers, mooring lines, pipeline spans, towed array sonar strings, and alike, the long flexible cylinders will respond in two degrees of freedom, where the identified difference in Strouhal Number is a significant aspect to be accounted for in the modelling of its dynamic behaviour.

Design and Evaluation of a Multi-Degree-of-Freedom Foot/Pedal Interface for Cycling

1992 ◽  
Vol 8 (2) ◽  
pp. 152-164 ◽  
Author(s):  
Dennis Wootten ◽  
Maury L. Hull
Keyword(s):  
Knee Joint ◽  
Significant Interaction ◽  
Degrees Of Freedom ◽  
Knee Injuries ◽  
Degree Of Freedom ◽  
Two Degrees Of Freedom ◽  
Factors Affecting ◽  
Freedom Of Movement ◽  
Sample Data ◽  
Comprehensive Study

Described is the design of a foot/pedal interface intended as a research tool in the study of overuse knee injuries in cycling. The interface enables the systematic variation of factors that may affect loads transmitted by the knee joint. It permits two degrees of freedom of movement, inversion/eversion and abduction/adduction rotations, either separately or in combination. The movement permitted by each degree of freedom can be either free or resisted by spring assemblies. Sample data were collected to demonstrate the function of the foot/pedal interface. With no spring resistance, the interface functioned as intended by allowing free movement of the foot. Significant interaction was seen between the two degrees of freedom, with more motion and a larger absolute mean occurring when both degrees of freedom were allowed simultaneously. This emphasizes the need for a multi-degree-of-freedom interface when undertaking a comprehensive study of the factors affecting loads transmitted by the knee.

A guide to classical flutter

1988 ◽  
Vol 92 (919) ◽  
pp. 339-355 ◽  
Author(s):  
L. T. Niblett
Keyword(s):  
Degrees Of Freedom ◽  
Normal Modes ◽  
Degree Of Freedom ◽  
Single Degree Of Freedom ◽  
Structural Coupling ◽  
Two Degrees Of Freedom ◽  
Single Degree ◽  
Lifting Surface ◽  
Classical Flutter ◽  
Comprehensive Study

Summary First essentials of classical flutter are demonstrated by a comprehensive study of the behaviour of a lifting surface with two degrees of freedom under the action of airforces limited to those in phase with displacement. Structural coupling between the coordinates is eliminated by taking the normal modes to be the deflection coordinates, and this results in conditions for stability with particularly concise forms. It is shown that the flutter stability can be seen to be very much a matter of the relative amplitudes of heave and pitch in the normal modes. In-quadrature airforces are then introduced and it is shown that they have little effect when the flutter is severe. They are of more importance in the milder forms of flutter, the extreme of which are shown to be little different from instabilities in a single degree of freedom.

An Innovative Approach to Detect Isomorphism in Planar and Geared Kinematic Chains Using Graph Theory

2017 ◽  
Vol 139 (12) ◽  
Author(s):  
Vinjamuri Venkata Kamesh ◽  
Kuchibhotla Mallikarjuna Rao ◽  
Annambhotla Balaji Srinivasa Rao
Keyword(s):  
Graph Theory ◽  
Degrees Of Freedom ◽  
Quantitative Measure ◽  
Simple Algorithm ◽  
Isomorphism Problem ◽  
Innovative Approach ◽  
Two Degrees Of Freedom ◽  
Kinematic Chains ◽  
Topological Characteristics ◽  
Interesting Area

Detection of isomorphism in planar and geared kinematic chains (GKCs) is an interesting area since many years. Enumeration of planar and geared kinematic chains becomes easy only when isomorphism problem is resolved effectively. Many researchers proposed algorithms based on topological characteristics or some coding which need lot of computations and comparisons. In this paper, a novel and simple algorithm is proposed based on graph theory by which elimination of isomorphic chains can be done very easily without any tedious calculations or comparisons. A new concept “Net distance” is proposed based on the graph theory to be a quantitative measure to assess isomorphism in planar kinematic chains (PKCs) as well as GKCs. The proposed algorithm is applied on nine-link two-degrees-of-freedom (DOF) distinct kinematic chains completely and the results are presented. Algorithm is tested on examples from eight-link 1-DOF, ten-link 1-DOF, 12-link 1-DOF, and 15link 4-DOF PKCs. The algorithm is also tested on four-, six-link 1-DOF GKCs to detect isomorphism. All the results are in agreement with the existing literature.

Trajectories Generated by a Novel Cam Driven Five-Bar Mechanism

2015 ◽  
Vol 799-800 ◽  
pp. 685-692
Author(s):  
Shinn Liang Chang ◽  
Dai Jia Juan ◽  
You Huang Syu
Keyword(s):  
Degrees Of Freedom ◽  
Trajectory Generation ◽  
Special Kind ◽  
Degree Of Freedom ◽  
Two Degrees Of Freedom ◽  
Different Types

In industry, the special kind of trajectory is often designed to fit the desired motion required. In literature, four-bar mechanism is popularly applied and well studied in the trajectory generation. Different types of trajectories are generated by the choose of the ratio of links. The five-bar mechanism is another popular one to generate the desired trajectory and it is more flexible due to it has two degrees of freedom. The geared five-bar mechanism is then commonly used by reducing the degree of freedom of the mechanism into one by implied one pair of gear. In this study, the trajectories generated by a novel cam driven five-bar mechanism proposed by the authors are investigated. It could supply more choices in the application of trajectory generation.

Successful performance of basic gestures in tablet technology in post stroke patients: A feasibility study

2019 ◽  
Vol 27 (6) ◽  
pp. 613-622 ◽  
Author(s):  
Stefan Thomas Kotzian ◽  
Sandra Haider ◽  
Igor Grabovac ◽  
Nikolaus Schubert ◽  
Spatt Josef
Keyword(s):  
Feasibility Study ◽  
Stroke Patients ◽  
Successful Performance ◽  
Post Stroke

Efficient simultaneous dense coding and teleportation with two-photon four-qubit cluster states

2016 ◽  
Vol 14 (05) ◽  
pp. 1650023 ◽  
Author(s):  
Cai Zhang ◽  
Haozhen Situ ◽  
Qin Li ◽  
Guang Ping He
Keyword(s):  
Degrees Of Freedom ◽  
Quantum States ◽  
Degree Of Freedom ◽  
Generation Rate ◽  
Entangled States ◽  
Dense Coding ◽  
Cluster States ◽  
Two Degrees Of Freedom ◽  
Classical Information ◽  
Two Photon

We firstly propose a simultaneous dense coding protocol with two-photon four-qubit cluster states in which two receivers can simultaneously get their respective classical information sent by a sender. Because each photon has two degrees of freedom, the protocol will achieve a high transmittance. The security of the simultaneous dense coding protocol has also been analyzed. Secondly, we investigate how to simultaneously teleport two different quantum states with polarization and path degree of freedom using cluster states to two receivers, respectively, and discuss its security. The preparation and transmission of two-photon four-qubit cluster states is less difficult than that of four-photon entangled states, and it has been experimentally generated with nearly perfect fidelity and high generation rate. Thus, our protocols are feasible with current quantum techniques.

Sign in / Sign up

Export Citation Format

Share Document