Smart Textile Systems Research Articles

Smart Textile-Integrated Microelectronic Systems for Wearable Applications.

The programmable nature of smart textiles makes them an indispensable part of an emerging new technology field. Smart textile-integrated microelectronic systems (STIMES), which combine microelectronics and technology such as artificial intelligence and augmented or virtual reality, have been intensively explored. A vast range of research activities have been reported. Many promising applications in healthcare, the internet of things (IoT), smart city management, robotics, etc., have been demonstrated around the world. A timely overview and comprehensive review of progress of this field in the last five years are provided. Several main aspects are covered: functional materials, major fabrication processes of smart textile components, functional devices, system architectures and heterogeneous integration, wearable applications in human and nonhuman-related areas, and the safety and security of STIMES. The major types of textile-integrated nonconventional functional devices are discussed in detail: sensors, actuators, displays, antennas, energy harvesters and their hybrids, batteries and supercapacitors, circuit boards, and memory devices.

A NiTi alloy weft knitted fabric for smart firefighting clothing

A prototype of a new shape-memory nitinol knitted fabric intended for use as an active thermal insulating interlining in firefighting protective clothing was developed in the study presented in this paper. Weft knitted fabrics were made from commercially available cold-worked nickel titanium alloy monofils. Knits were made on a manual knitting machine from a monofil measuring 0.1 mm in diameter, while a hand-made knit was prepared from a monofil measuring 0.2 mm in diameter. Nitinol fabrics were annealed at 500 °C to achieve an austenite transition temperature of 75 °C. A special constructed mould made of a steel frame and aluminium domes measuring 30 and 20 mm in height was used to give the nitinol fabrics a new temporary shape. A two-way, shape-memory effect of the nitinol fabrics was achieved using a 15-cycle training process. The achieved shape-memory effect was tested in a heated chamber at 100 °C, where bulges measuring 12–25 mm in height occurred. NiTi knits made from finer monofil were the most successful shape-memory knits. They were machine knitted and achieved sufficiently high bulges, measuring 18 or 12 mm, that facilitated large enough air gaps for effective thermal protection. A smart textile system was prepared by inserting the trained nitinol fabric into a pocket made from two textile fabric layers sewn together. When it was exposed to environmental temperatures of 75 °C and higher, it instantly changed its form from a two-dimensional shape to a three-dimensional shape, while increasing the air gap in the pocket. A quilted fabric made from such a smart textile system could be used in firefighting protective clothing to locally improve thermal insulation and protect the human skin from overheating or burns.

Using a smart textile system for classifying occupational manual material handling tasks: evidence from lab-based simulations

Physical monitoring systems represent potentially powerful assessment devices to detect and describe occupational physical activities. A promising technology for such use is smart textile systems (STSs). Our goal in this exploratory study was to assess the feasibility and accuracy of using two STSs to classify several manual material handling (MMH) tasks. Specifically, commercially-available ‘smart’ socks and a custom ‘smart’ shirt were used individually and in combination. Eleven participants simulated nine separate MMH tasks while wearing the STSs, and task classification accuracy was quantified subsequently using several common models. The shirt and socks, both individually and in combination, could classify the simulated tasks with greater than 97% accuracy. Thus, using STSs appears to have potential utility for discriminating occupational physical tasks in the work environment.Practitioner summary: A smart textile system could classify diverse MMH tasks with high accuracy. This technology may help in developing future ergonomic exposure assessment systems, with the goal of preventing occupational injuries.

A “Smart” Undershirt for Tracking Upper Body Motions: Task Classification and Angle Estimation

The use of interactive or “smart” textiles that have sensing material(s) incorporated into them supports an emerging technology for physical activity assessment called smart textile systems (STSs). STSs are an increasingly useful technology for researchers, athletes, patients, and others. In this paper, we developed and assessed a novel smart undershirt (SUS) that was designed to monitor low-back (thorax versus pelvis) and shoulder motions. The SUS consists of stretchable undershirt, electronic components, and an array of 11 body-worn sensors (BWSs) printed on the clothing. The BWSs are developed by coating electroactive polymers (i.e., polymerization) on the fabric and are wired using conductive threads. This shirt is the first smart garment for tracking both lower back and shoulder motions using printed textile sensors. The 16 participants performed 10 upper body movements while wearing the SUS for the purpose of assessing the accuracy of task classification and angle estimation. Input from the SUS led to classification accuracy at the individual levels up to 94% and planar angle estimations with errors on the order of 1.3° and 9.4° for the low back and shoulder, respectively. The performance was poorer, though, at the group level. The SUS appears to be a promising alternative for the purpose of monitoring upper body motions and activities.

Detection of Occupational Physical Activities using a Smart Textile System

Detection of Occupational Physical Activities using a Smart Textile System

Preferred Placement and Usability of a Smart Textile System vs. Inertial Measurement Units for Activity Monitoring.

Wearable sensors and systems have become increasingly popular in recent years. Two prominent wearable technologies for human activity monitoring are smart textile systems (STSs) and inertial measurement units (IMUs). Despite ongoing advances in both, the usability aspects of these devices require further investigation, especially to facilitate future use. In this study, 18 participants evaluate the preferred placement and usability of two STSs, along with a comparison to a commercial IMU system. These evaluations are completed after participants engaged in a range of activities (e.g., sitting, standing, walking, and running), during which they wear two representatives of smart textile systems: (1) a custom smart undershirt (SUS) and commercial smart socks; and (2) a commercial whole-body IMU system. We first analyze responses regarding the usability of the STS, and subsequently compared these results to those for the IMU system. Participants identify a short-sleeved shirt as their preferred activity monitor. In additional, the SUS in combination with the smart socks is rated superior to the IMU system in several aspects of usability. As reported herein, STSs show promise for future applications in human activity monitoring in terms of usability.

MagicSox: An E-textile IoT system to quantify gait abnormalities

Abstract The global society is increasingly facing the challenges that reduce mobility, quality of life, and independence. Gait disorders are often both a result of, and predictor of further issues, tied to the 15 million stroke patients annually world-wide. These individuals face a number of gait abnormalities including drop foot that is a pathological condition, limiting patients' ability to lift the foot from the ground during the swing phase of walking. In this research work, we introduce a novel smart textile system, MagicSox that is woven with multiple sensors distributed over the surface of the foot. The overarching goal of MagicSox is to quantify the gait abnormalities in remote settings such as patients' homes so that clinicians and physical therapists can assess their patients on daily basis. The paper provides a detailed architecture of MagicSox that leverages the computing and communication capabilities of a modern Internet of Things (IoT) processor, the Intel Curie. We have developed an Android smart phone app that uses Bluetooth low energy (BLE) and automates the multi-sensor data collection from MagicSox. In terms of signal processing of wearable sensor data, we adopted multiplication of backward differences (MOBD) to analyze the multi-modal time series data to distinguish drop foot events from normal walking cycles. We pursued a usability study on 12 healthy participants who were asked to walk normally and also to simulate drop foot cycles. We developed support vector machine (SVM) classifiers to analyze the data. The classification resulted in the accuracy of drop foot detection varying from 73.38 % − 99.02 % . The promising results now encourage us to evaluate MagicSox on stroke patients in future studies.

Effects of weaving structures and parameters on the radiation properties of three-dimensional fabric integrated microstrip antennas

In smart textile systems, the wireless communication between the wearer and the wider environment plays an important role, especially in medical applications. This can be achieved by integrating an antenna in textile materials. The low-profile microstrip antenna is a desirable choice for textile antennas and integrating this type of antenna into the three-dimensional woven fabric achieves the most integrated textile antenna structure up to now. Different from traditional antenna structures, the three-dimensional woven fabric integrated microstrip antenna has the radiation patch and ground plane totally woven with the yarns, where the radiation properties would strongly depend on the weaving structures and parameters. In this paper, a 1.9 GHz single patch microstrip antenna was designed and six types of antennas with different combinations of woven patches and ground planes were compared. The measured results showed that the three-dimensional woven antenna had adequate performance. In addition, the three-dimensional woven antenna with warp yarns parallel to the feeding direction exhibited a better return loss and radiation pattern than the antenna with weft yarn parallel to the feeding direction, due to the longer current path for the latter antenna based on simulated current distribution analysis. Furthermore, the effects of conductive yarn parameters on the antenna properties were discussed and yarn structures were suggested to obtain relatively ideal antenna performances.

How to Make Reliable, Washable, and Wearable Textronic Devices.

In this paper, the washability of wearable textronic (textile-electronic) devices has been studied. Two different approaches aiming at designing, producing, and testing robust washable and reliable smart textile systems are presented. The common point of the two approaches is the use of flexible conductive PCB in order to interface the miniaturized rigid (traditional) electronic devices to conductive threads and tracks within the textile flexible fabric and to connect them to antenna, textile electrodes, sensors, actuators, etc. The first approach consists in the use of TPU films (thermoplastic polyurethane) that are deposited by the press under controlled temperature and pressure parameters in order to protect the conductive thread and electrical contacts. The washability of conductive threads and contact resistances between flexible PCB and conductive threads are tested. The second approach is focused on the protection of the whole system—composed of a rigid electronic device, flexible PCB, and textile substrate—by a barrier made of latex. Three types of prototypes were realized and washed. Their reliabilities are studied.

Architecture of smart clothing for standardized wearable sensor systems

The field of wearable computing has great implications in the measurement of the human body and its surrounding environment, with potentially high impact in medical applications such as early detection, treatment, compliance monitoring, care for the frail and elderly, telemedicine, physical therapy, etc. [1]. Unfortunately, the field of wearable computing is still held back by the lack of a standardized framework and development process, forcing developers into custom and time intensive solutions. In this paper, the current progress of development of a universal smart textile system is discussed which would solve this problem and accelerate the field of smart wearable electronics, providing a universal platform for attaching several hundreds of sensors to clothing in convenient, unobtrusive and energy efficient ways. The main problems and potential solutions discussed in this article include power and data transfer wire topology, allowing the textile to be arbitrarily cut and sewn into smart clothing, data transmission architecture, providing high bandwidth and low energy data transfer, and support for miniaturization and elasticity, making the potential end product as unobtrusive as possible.

Enhanced thermal and hydrophobic surface properties of shape‐stabilized nanodiamond/fatty alcohol grafted poly(ethylene‐alt‐maleic anhydride) composite phase change materials

Fatty alcohol grafted poly(ethylene‐alt‐maleic anhydride) (PEMA‐g‐FA) are synthesized from esterification of poly (ethylene‐alt‐maleic anhydride) (PEMA) with tetradecanol and octadecanol. Obtained PEMA‐g‐FA's composites were prepared with different ratios of nanodiamond as phase change materials (PCM).The chemical structure of the synthesized PEMA‐g‐FA was investigated by Fourier transform infrared spectroscopy. Phase change behaviors of PEMA‐g‐FA and their composites were examined by using differential scanning calorimetry. Thermal stability of the samples was evaluated by thermogravimetric analysis. Moreover, the surface morphology of the samples was investigated by a scanning electron microscopy and atomic force microscope. The melting and freezing temperature and enthalpy of comb‐like polymers were increased with increasing the content of nanodiamond and the n‐alkyl side chains length. Finally, the obtained results prove that, thanks to high latent heat storage capacity and high thermal stability, the prepared comb‐like polymeric PCMs and their composites could be used in thermal energy storage applications. The prepared shape stabilized composite PCMs could be a promising material and could have practical applications in industries such as solar cooling refrigeration systems, solar air heating systems, and smart textile systems. POLYM. COMPOS., 39:1887–1895, 2018. © 2016 Society of Plastics Engineers

Novel textile systems for the continuous monitoring of vital signals: design and characterization.

In this article we present a smart textile system for the continuous monitoring of cardiorespiratory signals, produced and integrated with an industrial embroidery unit. The design of a T-shirt system, having embedded textile sensors and interconnects and custom designed circuit for data collection and Bluetooth transmission is presented. The performance of skin-contact textile electrodes, having distinctive electrical characteristics and surface morphologies, was characterized by measurements of signal to noise ratio, under dry and moisture conditions. The influence of the electrodes size and the wear resistance were addressed. Results of an electrocardiogram acquisition with a subject wearing the T-shirt and display on a smartphone are also shown. The presented smart textile systems exhibit good performance and versatility for custom demand production.

Shape-Memory Applications in Textile Design

Extensive efforts have been made in the research and development of smart textile systems in recent years. One of these developments in smart materials is shape memory applications. Shape memory materials (SMM) are smart materials that can remember and recover substantial programmed deformation upon activation and exposing to an external stimulus such as chemicals, temperature, pH, light, a magnetic field, etc. Shape memory materials have been used in many areas and textile application of this technology has covered a wide usage recently. Today's textile concept isn’t the similar to past and expectations of people from textile have been changing more and more. In this point, shape memory materials can answer these needs in textile due to its smart features. Shape-memory materials can be used in textile as clothing, yarn and fabric. The application possibilities are only limited by our imagination and creativity, so shape-memory productions have been able to gain a different aspect to textile.

Design of a Circularly Polarized Galileo E6-Band Textile Antenna by Dedicated Multiobjective Constrained Pareto Optimization

Designing textile antennas for real-life applications requires a design strategy that is able to produce antennas that are optimized over a wide bandwidth for often conflicting characteristics, such as impedance matching, axial ratio, efficiency, and gain, and, moreover, that is able to account for the variations that apply for the characteristics of the unconventional materials used in smart textile systems. In this paper, such a strategy, incorporating a multiobjective constrained Pareto optimization, is presented and applied to the design of a Galileo E6-band antenna with optimal return loss and wide-band axial ratio characteristics. Subsequently, different prototypes of the optimized antenna are fabricated and measured to validate the proposed design strategy.

A novel device based on smart textile to control heart’s activity during exercise

In recent years, several systems have been developed to control cardiac function during exercise, and some are also capable of recording RR data to provide heart rate variability (HRV) analyses. In this study we compare time between heart beats and HRV parameters obtained with a smart textile system (GOW; Weartech sl., Spain) and an electrocardiogram machine commonly used in hospitals during continuous cycling tests. Twelve cardiology patients performed a 30-min cycling test at stable submaximal intensity. RR interval data were recorded during the test by both systems. 3-min RR segments were taken to compare the time intervals between beats and HRV variables using Bland-Altman analyses and intraclass correlation coefficients. Limits of agreement (LoAs) on RR intervals were stable at around 3 ms (widest LoAs -5.754 to 6.094 ms, tightest LoAs -2.557 to 3.105 ms, medium LoAs -3.638 ± 0.812 to 3.145 ± 0.539 ms). HRV parameters related to short-term change presented wide LoAs (RMSSD -0.17 to 18.41 %, HF -17.64 to 33.21 %, SD1 -0.50 to 17.54 %) as an effect of the error measurement of the GOW system. The GOW system is a valid tool for controlling HR during physical activity, although its use as a clinical tool for HRV cannot be supported.

Textile touch sensors for wearable and ubiquitous interfaces

The design of textile touch sensing interaction was explored with the new metal composite embroidery yarns (MCEYs) and a simple and easy fabrication technique aimed towards robust and reliable pressure sensitive position sensors for wearable tangible interfaces. In this paper, the resistive sensing method of a potentiometer as an accurate positional indicator was chosen to make simple prototypes of MCEY embroidered touch sensors. A simple structure of embroidered potentiometer to create textile switches as an input device in a smart textile system was tested. Both one- and two-point sensing method were successfully demonstrated. A complete success rate on switching was observed. These simple but ingenious embroidered touch sensors showed the possibility of a soft, lightweight, flexible, freely foldable touchpad as a ubiquitous solution. It was also shown that these minimal fabrication technologies may be highly valued in the smart textile field thanks to their simplified interconnections, customizability and tailorability on double curvature surfaces.

Smart textiles: Challenges and opportunities

Smart textiles research represents a new model for generating creative and novel solutions for integrating electronics into unusual environments and will result in new discoveries that push the boundaries of science forward. A key driver for smart textiles research is the fact that both textile and electronics fabrication processes are capable of functionalizing large-area surfaces at very high speeds. In this article we review the history of smart textiles development, introducing the main trends and technological challenges faced in this field. Then, we identify key challenges that are the focus of ongoing research. We then proceed to discuss fundamentals of smart textiles: textile fabrication methods and textile interconnect lines, textile sensor, and output device components and integration of commercial components into textile architectures. Next we discuss representative smart textile systems and finally provide our outlook over the field and a prediction for the future.

Textile-based Antennas for Off-Body Communication

The need for textile-based antennas originates from the development of smart textile systems that emerged in the nineties. The aim is to increase the functionality of textiles, in most cases, clothing, by adding electronic systems. This allows the monitoring of physical (such as heart or respiration rate) as well as environmental (such as humidity or temperature) parameters through an embedded sensor network. The availability of micro electronics on the one hand, and new textile materials on the other, stimulates this evolution. The development of integratable textile-based sensors and flexible interconnections is continuously ongoing research. Also, wireless data transfer from the garment to a nearby base-station requires new developments, especially when the flexibility and comfort of the garment needs to be preserved. This paper gives a detailed overview on performed research and reveals the feasibility, design and manufacturing process of textile-based antennas for this off-body communication. The antennas are low profile, breathable, light-weight and simple in structure which make them suitable to be unobtrusively embedded in apparel and provide flexibility and satisfactory performance.

A roadmap on smart textiles

Though industrial exploitation of smart textile systems is still in its infancy, the technological implementation is increasing. This is the result of substantial research and development investments directed towards this emerging field. In order to stimulate the progress in smart textiles, emerging developments need to be identified and selectively strengthened. Hence, this issue reports on a three-dimensional roadmap on smart textiles. It aims at contributing to set future actions in research, education and technology development. Research activities and technological developments are mapped, barriers and drivers of technological, strategic and societal and economical origins are identified. Finally, recommendations are phrased on how to overcome barriers and to progress in the field of smart textiles.