Fabric-based strain sensors for measuring movement in wearable telemonitoring applications (original) (raw)
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Performance Evaluation of Knitted and Stitched Textile Strain Sensors
Sensors, 2020
By embedding conductive yarns in, or onto, knitted textile fabrics, simple but robust stretch sensor garments can be manufactured. In that way resistance based sensors can be fully integrated in textiles without compromising wearing comfort, stretchiness, washability, and ease of use in daily life. The many studies on such textile strain sensors that have been published in recent years show that these sensors work in principle, but closer inspection reveals that many of them still have severe practical limitations like a too narrow working range, lack of sensitivity, and undesired time-dependent and hysteresis effects. For those that intend to use this technology it is difficult to determine which manufacturing parameters, shape, stitch type, and materials to apply to realize a functional sensor for a given application. This paper therefore aims to serve as a guideline for the fashion designers, electronic engineers, textile researchers, movement scientists, and human–computer inter...
Advanced Materials Technologies, 2022
Textile strain sensors capable of monitoring human physiological signals and activities have great potential in health monitoring and sports. Integrating them into apparel to be wearable, repeatable, and sensitive remains a great challenge, impeding their practical applications. This paper reports a fabric strain sensor that can be seamlessly integrated into various apparel under precise tension through industrial‐scale production. A conductive core‐sheath polyester/carbon black multifilament (CSPCF) produced on a melt spinning machine is wrapped onto a spandex yarn via a yarn covering machine to manufacture a stretchable double‐covered conductive yarn (DCCY). The fabric strain sensor is specially designed and automatically produced on an industrial knitting machine by precisely integrating the DCCY into an elastic fabric. The sensing principle is contact and separation between neighboring spiral CSPCFs by stretching an arched “rainbow spring” like DCCY embedded in the fabric. The sensor has a high sensitivity of 2% strain detection limit, excellent durability and repeatability for 10 000 cycles, and a wide sensing range of 60% strain, even in a wet state or after repeatedly washing, bending, or rubbing. Three wearable products, by seamlessly integrating the sensor, are demonstrated to effectively and quantitatively detect bending motions of finger, elbow, and knee. Integrating textile strain sensors into apparel is a great challenge but a prerequisite for practical applications. This work presents a fabric strain sensor with arched double‐covered conductive yarn detecting strains through “rainbow spring” like contact and separation of the spiral core‐sheath PET/carbon black multifilaments. A knitted sensing fingerstall by seamle
A Novel Textile Stitch-Based Strain Sensor for Wearable End Users
Materials
This research presents an investigation of novel textile-based strain sensors and evaluates their performance. The electrical resistance and mechanical properties of seven different textile sensors were measured. The sensors are made up of a conductive thread, composed of silver plated nylon 117/17 2-ply, 33 tex and 234/34 4-ply, 92 tex and formed in different stitch structures (304, 406, 506, 605), and sewn directly onto a knit fabric substrate (4.44 tex/2 ply, with 2.22, 4.44 and 7.78 tex spandex and 7.78 tex/2 ply, with 2.22 and 4.44 tex spandex). Analysis of the effects of elongation with respect to resistance indicated the ideal configuration for electrical properties, especially electrical sensitivity and repeatability. The optimum linear working range of the sensor with minimal hysteresis was found, and the sensor’s gauge factor indicated that the sensitivity of the sensor varied significantly with repeating cycles. The electrical resistance of the various stitch structures c...
IEEE Sensors Journal, 2017
Long-term and minimally invasive joint angular measurements are required for monitoring everyday activities, motor rehabilitation sessions, and sport training. In this paper, we designed an innovative wearable device composed of a light, comfortable, and low-cost textile strain-resistance sensor. First, we proposed a methodology to characterize and to calibrate a commercial knitted textile. This characterization procedure represents an interesting result per se. It has been conducted on a single material, but its general characteristics make it suitable for analyzing the behavior of any conductive and stretchable fabrics. Second, we developed a wearable sensor (a goniometer) and we validated it using the humanoid robot SABIAN. Dynamic tests demonstrated that our wearable device is suitable for scenarios, where the accuracy of measurements is less relevant than the ability to continuously track joint movements in a not-obtrusive way.
Characterisation and Analysis of Elastomeric Tapes for Textile Strain Sensor Development
Continuous and online monitoring of body vital signs and kinematics is important for the present situation because of the stress levels of the human body. Currently used sensor systems for online monitoring are obtrusive and cannot be worn continuously for long time monitoring because of the lack in comfort of such systems. The development of electronics, communication and material science resulted in the development of Electronic Textiles. The uniqueness of this wearable E -Textiles is their flexibility, closeness to the body and comfort. The sensitivity, accuracy and repeatability of these systems are also high. Hence this research attempted to develop textile based strain sensor for goniometry application. This work discusses the development and characterization of elastomeric tapes for strain sensor application. The stress strain properties of base threads and commercially available elastomeric tapes have been analyzed for the selection of base fabric parameters. The sensitivity of the developed sensor was characterized using Zwick tensile tester.
Performance evaluation of sensing fabrics for monitoring physiological and biomechanical variables
Information …, 2005
In the last few years, the smart textile area has become increasingly widespread, leading to developments in new wearable sensing systems. Truly wearable instrumented garments capable of recording behavioral and vital signals are crucial for several fields of application. Here we report on results of a careful characterization of the performance of innovative fabric sensors and electrodes able to acquire vital biomechanical and physiological signals, respectively. The sensing function of the fabric sensors relies upon newly developed strain sensors, based on rubber-carboncoated threads, and mainly depends on the weaving topology, and the composition and deposition process of the conducting rubbercarbon mixture. Fabric sensors are used to acquire the respitrace (RT) and movement sensors (MS). Sensing features of electrodes, instead rely upon metal-based conductive threads, which are instrumental in detecting bioelectrical signals, such as electrocardiogram (ECG) and electromyogram (EMG). Fabric sensors have been tested during some specific tasks of breathing and movement activity, and results have been compared with the responses of a commercial piezoelectric sensor and an electrogoniometer, respectively. The performance of fabric electrodes has been investigated and compared with standard clinical electrodes.
Textile-Based Weft Knitted Strain Sensors: Effect of Fabric Parameters on Sensor Properties
Sensors, 2013
The design and development of textile-based strain sensors has been a focus of research and many investigators have studied this subject. This paper presents a new textile-based strain sensor design and shows the effect of base fabric parameters on its sensing properties. Sensing fabric could be used to measure articulations of the human body in the real environment. The strain sensing fabric was produced by using electronic flat-bed knitting technology; the base fabric was produced with elastomeric yarns in an interlock arrangement and a conductive yarn was embedded in this substrate to create a series of single loop structures. Experimental results show that there is a strong relationship between base fabric parameters and sensor properties.
2014
Wearable sensors for fitness tracking are becoming increasingly popular and are set to increase as smartwatches begin to dominate the wearable technology market. Wearable technology provides the capacity to track long-term trends in the wearer's health. In order for this to be adopted the technology must be easy to use and comfortable to wear. Textile based sensors are ideal as they conform to the body and can be integrated into the wearer's everyday wardrobe. This work discusses fabric stretch sensors that can measure body movements. An application using a sensor glove for home assessment of Rheumatoid Arthritis is presented. This work is the result of a multidisciplinary effort, involving expertise in material science and functional design, computer science, human health and performance and influenced by the end user needs.