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1

A Study on Electrical Performances and Lifetime of a Flexible Electrochromic Textile Device

Moretti C., Tao X., Koncar V., Koehl L.

Autex Research Journal

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2014

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Vol. 14, no. 2

76--81

EN

Using their ability to change their color according to an external stimulation, chromic materials can be used to form a color-changing textile. Electrochromism, more particularly, is a colour change phenomenon caused by the application of an electrical potential. A flexible textile electrochromic device composed of four layers is presented. In order to improve the lifetime of this structure, the electrical performances of the electrolyte layer are studied. A method to measure and calculate the resistance variations of the electrolyte applied on a textile cotton substrate is given. Relations between the electrical performances of the electrolyte and the electrochromic effect of the device are also highlighted.

2

Analysis of Vibrotactile Perception via e-Textile Structure Using Fuzzy Logic

Kursun-Bahadir S., Kalaoglu F., Koncar V.

Fibres & Textiles in Eastern Europe

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2012

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Vol. 20, no. 6A (95)

91--97

EN

The aim of this study is to evaluate vibrotactile perception via an e-textile structure on different parts of the body by different signal types and frequencies. First an e-textile structure was developed by the integration of a vibration motor to knitted fabric using conductive yarns. Then various signal waveforms at different frequencies were applied to diverse parts of the user's body via this novel textile structure. Signals were generated by using a DAQ (Data Acquisition) card. Finally vibrotactile perceptions were evaluated and compared by groups of people using fuzzy linguistic scales. It was found that the signal waveform and frequency had a significant effect on the vibrotactile perception. Furthermore the perception level of vibrotactile stimulation showed differences depending on the part of the human body. This e-textile based vibrotactile information could be highly valuable for applications like directional navigation, where the visual sense is restricted, for driving, for piloting and for medical applications like body relaxation against stress. Analiza postrzegania bezwzrokowego poprzez struktury tekstroniczne z zastosowaniem metody zbiorów rozmytych.

PL

Celem tej pracy jest ocena postrzegania bezwzrokowego poprzez struktury tekstroniczne umieszczone na różnych częściach ciała, stosując różne typy sygnałów i częstotliwości. Najpierw opracowano strukturę tekstroniczną przez połączenie silniczka i dzianiny za pomocą przędz przewodzących. Następnie przy udziale nowej struktury tekstylnej wysyłano sygnały o zróżnicowanych częstotliwościach do poszczególnych części ciała użytkownika. Otrzymane wyniki porównano stosując metodę zbiorów rozmytych. Stwierdzono, że częstotliwość i kształt fali sygnału miały znaczący wpływ na postrzeganie bezwzrokowe. Co więcej, poziom postrzegania wibracji był różny w zależności od miejsca usytuowania na ciele człowieka. Opracowane układy mogą znaleźć zastosowania zarówno przy sterowaniu ruchem jak i w medycynie.

3

Assessing the Signal Quality of an Ultrasonic Sensor on Different Conductive Yarns Used as Transmission Lines

Kursun-Bahadir S., Koncar V., Kalaoğlu F., Cristian I, Thomassey S

Fibres & Textiles in Eastern Europe

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2011

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Vol. 19, no. 5 (88)

75--81

EN

The field of electronic textiles is still relatively new and extending due to technology miniaturisation. In this article, the integration of an ultrasonic sensor into a textile structure was realised and analysed in order to develop a system able to help visually impaired people. The performance of ultrasonic sensors was tested by means of five different conductive yarns used as transmission lines, in three different configurations for the purpose of detecting the eventual existing off disturbances and their values. Finally, the influence of the conductive yarn type on the performance of the ultrasonic sensor was discussed. The results highlighted that the linear resistance of conductive yarn has a strong influence on the sensor’s signal quality.

PL

Tekstylne wyroby tekstroniczne są ciągle nową dziedziną wymagającą intensywnych badań. W artykule opisano badania związane z integracją czujników ultradźwiękowych w odzieży tekstronicznej, które mogą być pomocne np. przy identyfikacji przedmiotów przez niewidomych. Zachowanie tych czujników badano przy zastosowaniu pięciu różnych przędz przewodzących stosowanych jako linie przesyłowe, w trzech różnych konfiguracjach dla kreślenia ewentualnie występujących zakłóceń i ich wielkości. Po dyskusji wyników stwierdzono, że wartość rezystancji liniowej stosowanych przędz odgrywa istotna rolę w jakości sygnałów przekazywanych przez czujniki ultradźwiękowe.

4

Derived piecewise continuous controller: application to nonlinear mechanical robot's trajectory tracking

Wang H., Vasseur C., Koncar V., Chamroo A., Christov N.

Systems Science

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2009

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Vol. 35, no 4

39-48

EN

In this paper, a derived piecewise continuous controller based method for an X-Y robot system trajectory tracking is proposed. The controller, which is based on the theory of particular hybrid systems called piecewise continuous systems characterized by autonomous switching and controlled impulses, uses only the robot's position measurement for feedback and does not require any identification work of the electromechanical system. The effectiveness and robustness of the method developed are analyzed theoretically and experimented with different type references on a real time X-Y robot system.

5

Electrical properties of conductive polymers: pet - nanocomposites’ fibres

Kim B., Koncar V., Devaux E.

Autex Research Journal

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2004

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Vol. 4, no. 1

9--13

EN

Researches in the field of conductive polym ers have attracted considerable attention for more then 20 years. Among the conductive polymers, polyaniline and polypyrrole have drawn considerable interest because of their economical importance, good environmental stability and satisfactory electrical conductivity when doped. On the other hand, electrically conductive materials such as aluminium powder, graphite and carbon nanotubes have very interesting conductive properties and are promising in the synthesis of new composite conductive materials. In almost all studies, conducting polymer films are developed and then electrical and mechanical properties are tested. In our paper, the conducting polymer fibres have been obtained by melt mixing and chemical coating on the fibres. Different conductive materials have been used in order to obtain conductive polypropylene-based fibres with specific electrical and mechanical properties. The electric conductivity and morphol ogical characteristics of these fibres have been investigated and the results are discussed. The originality of our approach lies in our having created conductive fibres based on conductive polymers. These fibres are intended for use in creating conductive yarns and realising connections in smart clothing, or producing conductive fabrics which can be used as electromagnetic shields. These developments have been carried out in order to create new multifunctional textile structures for different applications in the field of intelligent and communication apparel or other similar branches.

6

Diffusion of disperse dyes into supermicrofibres

Park K. H, Koncar V.

Autex Research Journal

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2004

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Vol. 4, no. 1

45--51

EN

All dyers share the common goal of achieving the correct shade as early as the first dyeing. But the dyeing process is very complex, being characterised by the diffusion- controlled sorption of dyes that depends on several physicochemical parameters. Moreover, the dyeing properties relating to microfibres and conventional fibres are caused by different properties such as the exposed surface area and the crystallinity index. Wilson and Hill developed equations describing the uptake rate of disperse dyes by a cylindrical fibre model as a function of t he diffusion coefficient and the nature of the dyebath. The inverse of Shibusawa’s polynomial approximation of Hill’s and Wilson’s equation is used to compute the diffusion coefficient, which depends on the initial dye concentration, the time and the fibre count at a fixed temperature. In this paper, the sorption isotherms, the diffusion coefficient, the dye concentration evolution into the fibres and the dyeing uptake rate are computed from experimental results for conventional fibres, microfibres and supermicrofibres. The sorption isotherms and the diffusion coefficient evolutions as a function of time, initial dye concentration and temperature for supermicrofibres are discussed by considering the surface area and the diffusional boundary layer’s influence. Important differences in the dyeing properties are observed, depending on the fibre count, which should be useful in the optimisation of the supermicrofibre dyeing process. The aim is to provide a tool for dyeing practitioners to increase dyeing reproducibility and to improve the performance of ‘right-first-time’ production.