Search Results (14)

The “Embroidery Triboelectric Nanogenerator” (E-TENG) is a wearable device that extracts energy from human motion by making use of the triboelectric phenomena, in addition to conductive fabric along with embroidery threads. One of the greatest ways to transform ambient vibrational energy from the human body is to use a wearable triboelectric energy harvester. In this study, different E-TENGs were developed using conductive fabric as an electrode and two different triboelectric yarns, 100% Polyester (electron donor) and Nylon 6,6 (electron receiver). To investigate the electrical outputs and energy-collecting potential of the ETENG, different stitch length and line spacing of embroidery TENG were investigated by testing samples in a specially manufactured tapping and sliding devices. The optimized wearable embroidery energy harvester effectively captured 72 μJ (12 V) of human motion energy in a 1 μF capacitor in 120 s and 307.5 μJ (24.8 V) of energy in a 1 μF capacitor by 1.5 Hz sliding motion in 300 s from an ETFS3.1 sample. A maximum of 4.5 μJ (3 V) was collected in a 1 μF capacitor from ETFS2.3 using a tapping machine for 520 s at a 2 Hz tapping motion and a 50 mm separation distance. The effects of the stitch length and line spacing in the embroidered structure on the electrical output performance of the embroidery energy-harvesting TENG were investigated. Full article

The longest $(s,t)$-path problem on supergrid graphs is known to be NP-complete. However, the complexity of this problem on supergrid graphs with or without holes is still unknown.In the past, we presented linear-time algorithms for solving the longest $(s,t)$-path problem on L-shaped and C-shaped supergrid graphs, which form subclasses of supergrid graphs without holes. In this paper, we will determine the complexity of the longest $(s,t)$-path problem on O-shaped supergrid graphs, which form a subclass of supergrid graphs with holes. These graphs are rectangular supergrid graphs with rectangular holes. It is worth noting that O-shaped supergrid graphs contain L-shaped and C-shaped supergrid graphs as subgraphs, but there is no inclusion relationship between them. We will propose a linear-time algorithm to solve the longest $(s,t)$-path problem on O-shaped supergrid graphs. The longest $(s,t)$-paths of O-shaped supergrid graphs have applications in calculating the minimum trace when printing hollow objects using computer embroidery machines and 3D printers. Full article

Supergrid graphs are derived by computing stitch paths for computerized embroidery machines. In the past, we have studied the Hamiltonian-related properties of supergrid graphs and their subclasses of graphs. In this paper, we propose a generalized graph class for supergrid graphs called extended supergrid graphs. Extended supergrid graphs include grid graphs, supergrid graphs, diagonal supergrid graphs, and triangular supergrid graphs as subclasses of graphs. In this paper, we study the problems of domination and independent domination on extended supergrid graphs. A dominating set of a graph is the subset of vertices on it, such that every vertex of the graph is in this set or adjacent to at least a vertex of this set. If any two vertices in a dominating set are not adjacent, this is called an independent dominating set. Domination and independent domination problems find a dominating set and an independent dominating set with the least number of vertices on a graph, respectively. The domination and independent domination set problems on grid graphs are known to be NP-complete, meaning that these two problems on extended supergrid graphs are also NP-complete. However, the complexities of these two problems in other subclasses of graphs remain unknown. In this paper, we first prove that these two problems on diagonal supergrid graphs are NP-complete, then, by a simple extension, we prove that these two problems on supergrid graphs and triangular supergrid graphs are also NP-complete. In addition, these two problems on rectangular supergrid graphs are known to be linearly solvable; however, the complexities of these two problems on rectangular triangular-supergrid graphs remain unknown. This paper provides tight upper bounds on the sizes of the minimum dominating and independent dominating sets for rectangular triangular-supergrid graphs. Full article

The main purpose of the article is to present the possibilities of producing composite reinforcement with the use of a computer embroidery machine. The study below presents the results of strength tests of composites containing technical embroidery, woven fabric, and UD fabric as the reinforcement. Each of the samples was made of the same material—flax roving. The samples differed from each other in the arrangement of layers in the reinforcement. The composites were made using the infusion method with epoxy resin. The embroidery was made on a ZSK embroidery machine, type JCZA 0109-550. A total of 12 types of composites were produced and tested. The test material was subjected to strength tests—tensile strength, tensile elongation, and shear strength, on the INSTRON machine. As the research showed, the use of technical embroidery as a composite reinforcement increases its tensile strength. Furthermore, the use of embroidery is a vertical reinforcement of the composite and prevents the formation of interlayer cracks. The technology of technical embroidery allows for optimizing the mechanical values of the composite reinforcement. Full article

Respiration monitoring is a very important indicator of health status. It can be used as a marker in the recognition of a variety of diseases, such as sleep apnea, asthma or cardiac arrest. The purpose of the present study is to overcome limitations of the current state of the art in the field of respiration monitoring systems. Our goal was the development of a lightweight handheld device with portable operation and low power consumption. The proposed approach includes a textile capacitive sensor with interdigitated electrodes embroidered into the facemask, integrated with readout electronics. Readout electronics is based on the direct interface of the capacitive sensor and a microcontroller through just one analog and one digital pin. The microcontroller board and sensor are powered by a smartphone or PC through a USB cable. The developed mobile application for the Android™ operating system offers reliable data acquisition and acts as a bridge for data transfer to the remote server. The embroidered sensor was initially tested in a humidity-controlled chamber connected to a commercial impedance analyzer. Finally, in situ testing with 10 volunteering subjects confirmed stable operation with reliable respiration monitoring. Full article

A graph is called Hamiltonian connected if it contains a Hamiltonian path between any two distinct vertices. In the past, we proved the Hamiltonian path and cycle problems for general supergrid graphs to be NP-complete. However, they are still open for solid supergrid graphs. In this paper, first we will verify the Hamiltonian cycle property of C-shaped supergrid graphs, which are a special case of solid supergrid graphs. Next, we show that C-shaped supergrid graphs are Hamiltonian connected except in a few conditions. For these excluding conditions of Hamiltonian connectivity, we compute their longest paths. Then, we design a linear-time algorithm to solve the longest path problem in these graphs. The Hamiltonian connectivity of C-shaped supergrid graphs can be applied to compute the optimal stitching trace of computer embroidery machines, and construct the minimum printing trace of 3D printers with a C-like component being printed. Full article

An e-textile mat with capacitive textile sensors was designed and manufactured to monitor body position and prevent decubitus ulcers in the case of bedridden people. The sensors were incorporated through a process of machine embroidery with electrically conductive threads. A new production method for the conductive threads is still expected to be developed, resulting in good conductive properties, high wear resistance and durability. Samples of five variants of motifs without cross-stitching were studied, and the capacity and electrical resistance were determined experimentally. A prototype of the e-textile mat was made with a motif showing the best ratio between the inserted thread and the measured capacity. A hardware solution and a software application for collecting, processing and visualising the received information were developed. Tests were performed in real conditions, which clearly showed that the designed e-textile mat could be successfully applied for non-invasive and continuous control of the position of the human body in a supine position to prevent decubitus ulcers. Full article

This article describes the development of transcutaneous nerve stimulating electrodes (TENS) by means of electrically conductive ink and conductive yarn. The scope of work covered a selection of three types of knitwear with a similar surface weight with different raw material composition. Stimulating electrodes were made by means of film printing and machine embroidery. The electrodes were verified after friction tests, washing, and mechanical deformation. Each process was followed by a check of the resistive properties and assessment of the sensations in order to evaluate their performance. Tests of the surface resistance of research materials confirmed the possibility of preparing textile electrodes for electrostimulation with the use of the film-printing technique and machine embroidery. Resistance of the electrodes made on all types of substrates ranged from approximately 1.00 × 10⁻² Ω to around 2.00 × 10² Ω, while the electrodes are commercially available at the level of approximately 3.5 × 10⁵ Ω. This paper underpins the validation of the conclusion that operational processes do not adversely affect the functioning of the developed textile electrodes. Full article

The garment manufacturing industry is a labor-intensive industry, with one of the slowest transitions to automation. Hence, it is essential to build a smart factory based on automated systems to improve productivity and allow responsive production in the market. In this study, the manufacturing processes for a smart sports bra were established and optimized using various automated machines. For this system, computer-based 3D virtual design software, a technical embroidery machine, an automatic cutting machine, an industrial robot arm with gripper, and an industrial pattern sewing machine were used. The design and materials of the sports bra were selected considering embroidery, cutting, robot gripping, and sewing processes. In addition, conductive thread and light-emitting diode (LED) sequences were used to implement smart functions to the sports bra. Transport of intermediate materials, work orders, and process conditions were optimized to improve the flexible connection of each process and the quality of the final product. This study suggests the concept of the automated manufacturing system that minimizes human intervention by connecting the processes needed to produce a smart sports bra using various automation equipment and programs already used in the industry. Full article

In this study, a strain gauge sensor based on a change of contact or network structure between conductive materials was implemented using the handle-machine embroidery technique, and the variables (embroidery shape, embroidery distance, embroidery size, and implementation location) affecting its performance were studied. As a result of Experiment I on the structure of embroidery suitable for joint motion monitoring, the embroidery distance, rather than the embroidery size, was found to have a significant effect on the electric resistance changes caused by elongation. Based on the results of Experiment I, two types of zigzag embroideries, four types of embroideries with few contact points, and two types of embroideries with more contact points (all with short distances (2.0)) were selected for Experiment II (the dummy motion experiment). As a result of the dummy motion experiment, it was found that the locations of the suitable embroidered sensors for joint motion monitoring was the HJP (Hinge Joint Position) in the ‘types without a contact point’ (zigzag) and the LHJP (Lower Hinge Joint Position) in the ‘types with more contact points’. On the other hand, although there was no consistency among the ‘types with few contact points’, the resistance changes measured by the 2CP and 7CP embroidered sensors showed similar figures and patterns, and the HJP location was most suitable. The resistance changes measured by the 4CP and 6CP embroidered sensors exhibited no consistent patterns, but the LHJP locations were more suitable. These results indicate that the location of the HJP is suitable for measuring joint motion in the ‘type without a contact point’, and the location of the LHJP is suitable for measuring joint motion when the number of contact points exceeds a certain limit. Among them, the average resistance change of the 9CP sensor located at the LHJP was 40 Ω with the smallest standard deviation of less than 1, and it is thus considered to have the best performance among all the sensors. Full article

Electrically-driven direct current (DC) motors are the core component of conventional robots thanks to the ease of computer control and high torque for their size. However, DC motors are often manually attached and soldered into robotic assemblies, and they are not flexible. For soft robotics, researchers have looked to new, compliant materials that are compatible with 3-D printing or other automated assembly methods. In this work we use a computer-controlled embroidery machine to create flat motor windings in flexible fabrics. We model their electromagnetic fields and present them as linear actuators that move a permanent magnet attached to a cable. The fabrication method puts some constraints on the coil design, which are discussed. However, the planar nature of the embroidered sheets enables the designer to use laminar fabrication methods, such as stacking or layering into parts, during 3-D printing. The soft motor windings produced static holding forces of up to 0.25 N and could lift a 0.3 g mass several cm using direct drive. A 3-D printed mechanical amplifier with two stages was able to quadruple the lifting mass, reducing the travel by a factor of 4. Machine embroidery-installed cables and motor coils could lead to “bolts and nuts free” fabrication of thin, electrically-driven cable actuators. Full article

Natural organisms use a combination of contracting muscles and inextensible fibers to transform into controllable shapes, camouflage into their surrounding environment, and catch prey. Replicating these capabilities with engineered materials is challenging because of the difficulty in manufacturing and controlling soft material actuators with embedded fibers. In addition, while linear and bending motions are common in soft actuators, rotary motions require three-dimensional fiber wrapping or multiple bending or linear elements working in coordination that are challenging to design and fabricate. In this work, an automatic embroidery machine patterned Kevlar™ fibers and stretchable optical fibers into inflatable silicone membranes to control their inflated shape and enable sensing. This embroidery-based fabrication technique is simple, low cost, and allows for precise and custom patterning of fibers in elastomers. Using this technique, we developed inflatable elastomeric actuators embedded with a planar spiral pattern of high-strength Kevlar™ fibers that inflate into radially symmetric shapes and achieve nearly 180° angular rotation and 10 cm linear displacement. Full article

We present a new methodology to create colorful textile antennas that can be embroidered within logos or other aesthetic shapes. Conductive threads (e-threads) have already been used in former embroidery unicolor approaches as attributed to the corresponding conductive material, viz. silver or copper. But so far, they have not been adapted to ‘print’ colorful textile antennas. For the first time, we propose an approach to create colorful electronic textile shapes. In brief, the embroidery process uses an e-thread in the bobbin case of the sewing machine to embroider the antenna on the back side of the garment. Concurrently, a colorful assistant yarn is threaded through the embroidery needle of the embroidery machine and used to secure or ‘couch’ the e-threads onto the fabric. In doing so, a colorful shape is generated on the front side of the garment. The proposed antennas can be unobtrusively integrated into clothing or other accessories for a wide range of applications (e.g., wireless communications, Radio Frequency IDentification, sensing). Full article

This paper will review the evolution of wearable textile antennas over the last couple of decades. Particular emphasis will be given to the process of embroidery. This technique is advantageous for the following reasons: (i) bespoke or mass produced designs can be manufactured using digitized embroidery machines; (ii) glue is not required and (iii) the designs are aesthetic and are integrated into clothing rather than being attached to it. The embroidery technique will be compared to alternative manufacturing processes. The challenges facing the industrial and public acceptance of this technology will be assessed. Hence, the key opportunities will be highlighted. Full article