1,567 research outputs found

    A review of contemporary techniques for measuring ergonomic wear comfort of protective and sport clothing

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    Protective and sport clothing is governed by protection requirements, performance, and comfort of the user. The comfort and impact performance of protective and sport clothing are typically subjectively measured, and this is a multifactorial and dynamic process. The aim of this review paper is to review the contemporary methodologies and approaches for measuring ergonomic wear comfort, including objective and subjective techniques. Special emphasis is given to the discussion of different methods, such as objective techniques, subjective techniques, and a combination of techniques, as well as a new biomechanical approach called modeling of skin. Literature indicates that there are four main techniques to measure wear comfort: subjective evaluation, objective measurements, a combination of subjective and objective techniques, and computer modeling of human–textile interaction. In objective measurement methods, the repeatability of results is excellent, and quantified results are obtained, but in some cases, such quantified results are quite different from the real perception of human comfort. Studies indicate that subjective analysis of comfort is less reliable than objective analysis because human subjects vary among themselves. Therefore, it can be concluded that a combination of objective and subjective measuring techniques could be the valid approach to model the comfort of textile materials

    Wearable Sensors and Smart Devices to Monitor Rehabilitation Parameters and Sports Performance: An Overview

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    A quantitative evaluation of kinetic parameters, the joint’s range of motion, heart rate, and breathing rate, can be employed in sports performance tracking and rehabilitation monitoring following injuries or surgical operations. However, many of the current detection systems are expensive and designed for clinical use, requiring the presence of a physician and medical staff to assist users in the device’s positioning and measurements. The goal of wearable sensors is to overcome the limitations of current devices, enabling the acquisition of a user’s vital signs directly from the body in an accurate and non–invasive way. In sports activities, wearable sensors allow athletes to monitor performance and body movements objectively, going beyond the coach’s subjective evaluation limits. The main goal of this review paper is to provide a comprehensive overview of wearable technologies and sensing systems to detect and monitor the physiological parameters of patients during post–operative rehabilitation and athletes’ training, and to present evidence that supports the efficacy of this technology for healthcare applications. First, a classification of the human physiological parameters acquired from the human body by sensors attached to sensitive skin locations or worn as a part of garments is introduced, carrying important feedback on the user’s health status. Then, a detailed description of the electromechanical transduction mechanisms allows a comparison of the technologies used in wearable applications to monitor sports and rehabilitation activities. This paves the way for an analysis of wearable technologies, providing a comprehensive comparison of the current state of the art of available sensors and systems. Comparative and statistical analyses are provided to point out useful insights for defining the best technologies and solutions for monitoring body movements. Lastly, the presented review is compared with similar ones reported in the literature to highlight its strengths and novelties

    Tekstiilielektrodit electromyografiamittauksissa

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    This thesis investigates the use of conductive textiles as the material of surface electromyography electrodes especially in the case of hand gesture recognition. Several conductive textile materials are used to design electrode setups integrated in sleeve to measure an 8-channel EMG signal around forearm. The electric properties of the electrodes are investigated and the EMG signal is used in a data classification experiment to assess the performance of the textile electrodes in gesture recognition compared to conventional medical grade electrodes. The design and manufacturing process is also described in order to underline all benefits and challenges associated with the materials and methods. This thesis shows that textile electrodes are a viable option for conventional wet gel electrodes in gesture recognition applications.Tämä diplomityö tutkii johtavien tekstiilien soveltuvuutta pintaelektrodien materiaaliksi erityisesti mitattaessa lihasaktiivisuussignaalia (EMG) kyynärvarren lihaksista käden eleiden tunnistamista varten. Työssä mitataan elektrodien sähköisiä ominaisuuksia ja verrataan niitä perinteisiin kliinisiin pintaelektrodeihin. Diplomityö esittää myös tekstiilien ja työtapojen vahvuuksia ja heikkouksia, jotka ilmenivät prototyyppien suunnittelu- ja valmistusprosessin aikana. Tulokset osoittavat, että tekstiilielektrodit soveltuvat erittäin hyvin käden eleiden tunnistamiseen pyrkiviin mittauksiin

    Ergowear: desenvolvimento de um vestuário inteligente para monitorização postural e biofeedback

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    Dissertação de mestrado em Engenharia Biomédica (especialização em Eletrónica Médica)Atualmente, as Lesões Musculoesqueléticas Relacionadas com o Trabalho (LMERT) são considera das o ”problema relacionado com o trabalho mais prevalente”na União Europeia, levando a um custo estimado de cerca de 240 biliões de euros. Em casos mais severos, estes distúrbios podem causar danos vitalícios à saúde do trabalhador, reduzindo a sua qualidade de vida. De facto, LMERTs são con sideradas a principal causa da reforma precoce dos trabalhadores. Foi reportado que os segmentos da parte superior do corpo são mais suceptíveis ao desenvolvimento de LMERTs. Para mitigar a prevalência de LMERTs, ergonomistas maioritariamente aplicam métodos de avaliação observacionais, que são alta mente dependentes da experiência do analista, e apresentam baixa objetividade e repetibilidade. Desta maneira, esforços têm sido feitos para desenvolver ferramentas de avaliação ergonómica baseadas na instrumentação, para compensar essas limitações. Além disso, com a ascensão do conceito da indústria 5.0, o trabalhador humano volta a ser o foco principal na indústria, juntamente com o robô colaborativo. No entanto, para alcançar uma relação verdadeiramente colaborativa e simbiótica entre o trabalhador e o robô, este último precisa de reconhecer as intenções do trabalhador. Para superar este obstáculo, sis temas de captura de movimento podem ser integrados nesta estrutura, fornecendo dados de movimento ao robô colaborativo. Esta dissertação visa a melhoria de um sistema de captura de movimento autónomo, da parte supe rior do corpo, de abordagem inercial que servirá, não apenas para monitorizar a postura do trabalhador, mas também avaliar a ergonomia do usuário e fornecer consciencialização postural ao usuário, por meio de motores de biofeedback. Além disso, o sistema foi já idealizado tendo em mente a sua integração numa estrutura colaborativa humano-robô. Para atingir estes objetivos, foi aplicada uma metodologia de design centrado no utilizador, começando pela análise do Estado da Arte, a avaliação das limitações do sistema anterior, a definição dos requisitos do sistema, o desenvolvimento da peça de vestuário, arquite tura do hardware e arquitetura do software do sistema. Por fim, o sistema foi validado para verificar se estava em conformidade com os requisitos especificados. O sistema é composto por 9 Unidades de Medição Inercial (UMI), posicionados na parte inferior e superior das costas, cabeça, braços, antebraços e mãos. Também foi integrado um sistema de atuação, para biofeedback postural, composto por 6 motores vibrotáteis, localizados na região lombar e próximo do pescoço, cotovelos e pulsos. O sistema é alimentado por uma powerbank e todos os dados adquiridos são enviados para uma estação de processamento, via WiFi (User Datagram Protocol (UDP)), garantindo autonomia. O sistema tem integrado um filtro de fusão Complementar Extendido e uma sequência de calibração Sensor-para-Segmento estática, de maneira a aumentar a precisão da estimativa dos ângulos das articulações. Além disso, o sistema é capaz de amostrar os dados angulares a 240 Hz, enquanto que o sistema anterior era capaz de amostrar no máximo a 100 Hz, melhorando a resolução da aquisição dos dados. O sistema foi validado em termos de hardware e usabilidade. Os testes de hardware abordaram a caracterização da autonomia, frequência de amostragem, robustez mecânica e desempenho da comuni cação sem fio do sistema, em diversos contextos, e também para verificar se estes estão em conformidade com os requisitos técnicos previamente definidos, que foi o caso. Adicionalmente, as especificações da nova versão do sistema foram comparadas com a anterior, onde se observou uma melhoria direta signifi cativa, como por exemplo, maior frequência de amostragem, menor perda de pacote, menor consumo de corrente, entre outras, e com sistemas comerciais de referência (XSens Link). Testes de usabilidade foram realizados com 9 participantes que realizaram vários movimentos uniarticulares e complexos. Após os testes, os usuários responderam a um questionário baseado na Escala de Usabilidade do Sistema (EUS). O sistema foi bem aceite pelos os usuários, em termos de estética e conforto, em geral, comprovando um elevado nível de vestibilidade.Nowadays, Work-Related Musculoskeletal Disorders (WRMSDs) are considered the ”most prevalent work-related problem” in the European Union (EU), leading to an estimated cost of about 240 billion EUR. In more severe cases, these disorders can cause life-long impairments to the workers’ health, reducing their quality of life. In fact, WRMSDs are the main cause for the workers’ early retirement. It was reported that the upper body segments of the worker are more susceptible to the development of WRMSDs. To mitigate the prevalence of WRMSD, ergonomists mostly apply observational assessment methods, which are highly dependant on the analyst’s expertise, have low objectivity and repeatability. Therefore, efforts have been made to develop instrumented-based ergonomic assessment tools, to compensate for these limitations. Moreover, with the rise of the 5.0 industry concept, the human worker is once again the main focus in the industry, along with the Collaborative Robot (cobot). However, to achieve a truly collaborative relation between the worker and the cobot, the latter needs to know the worker’s intentions. To surpass this obstacle, Motion Capture (MoCap) systems can be integrated in this framework, providing motion data to the cobot. This dissertation aims at the improvement of a stand-alone, upper-body, inertial, MoCap system, that will serve to not only monitor the worker’s posture, but also to assess the user’s ergonomics and provide posture awareness to the user, through biofeedback motors. Furthermore, it was also designed to integrate a human-robot collaborative framework. To achieve this, a user-centred design methodology was applied, starting with analyzing the State of Art (SOA), assessing the limitations of the previous system, defining the system’s requirements, developing the garment, hardware architecture and software architecture of the system. Lastly, the system was validated to ascertain if it is in conformity with the specified requirements. The developed system is composed of 9 Inertial Measurement Units (IMUs), placed on the lower and upper back, head, upper arms, forearms and hands. An actuation system was also integrated, for postural biofeedback, and it is comprised of 6 vibrotactile motors, located in the lower back, and in close proximity to the neck, elbows and wrists. The system is powered by a powerbank and all of the acquired data is sent to a main station, via WiFi (UDP), granting a standalone characteristic. The system integrates an Extended Complementary Filter (ECF) and a static Sensor-to-Segment (STS) calibration sequence to increase the joint angle estimation accuracy. Furthermore, the system is able to sample the angular data at 240 Hz, while the previous system was able to sample it at a maximum 100 Hz, improving the resolution of the data acquisition. The system was validated in terms of hardware and usability. The hardware tests addressed the char acterization of the system’s autonomy, sampling frequency, mechanical robustness and wireless commu nication performance in different contexts, and ascertain if they comply with the technical requirements, which was the case. Moreover, the specifications of the new version were compared with the previous one, where a significant direct improvement was observed, such as, higher sampling frequency, lower packet loss, lower current consumption, among others, and with a commercial system of reference (XSens Link). Usability tests were carried out with 9 participants who performed several uni-joint and complex motions. After testing, users answered a questionnaire based on the System Usability Scale (SUS). The system was very well accepted by the participants, regarding aesthetics and overall comfort, proving to have a high level of wearability

    Incorporating Modular Arrangement of Predetermined Time Standard with a Wearable Sensing Glove

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    “Performance” – a common watchword in the present age, and that which is optimized through the most functional methodology of investigating the work procedure. This encompassed the auditing, updating of the tasks, while at the same time, applied automation and mechanization. The Modular Arrangement of Predetermined Time Standard (MODAPTS) is a useful application of a work measurement technique that allow a greater variety of work for manufacturing, engineering, and administrative service activities to be measured quickly with ease and accuracy. The MODAPTS, however, made it extremely difficult for engineers to use because it required an ample amount of time to analyze and code the raw data. A new design was proposed to help resolve the conventional system\u27s inadequacy because in MODAPTS, each task cycle of a minute required about 2 hours to calculate and document, and also, the judgment of the analysts varied for the same task. This study aimed to reduce the time taken for the traditional MODAPTS documentation usually took and produced unified results by integrating MODAPTS with a Sensing Wearable Glove while maintaining the same performance. The objective was to introduce an easy, cost-effective solution, and to compare the accuracy of coding between manual and automated calculated MODAPTS while maintaining consistent performance. This study discusses the glove and accompanying software design that detected movements using flex sensors, gyroscopes, microcontrollers, and pressure sensors. These movements were translated into analog data used to create MODAPTS codes as an output, which then sent the data wirelessly using the Bluetooth module. The device designed in this study is capable of sensing gestures for various operations, and the traditional method was compared to the proposed method. This was in turn, validated using the two-way ANOVA analysis. It was observed that the sensor-based glove provided efficient and reliable results, just like the traditional method results while maintaining the same performance

    Designing smart garments for rehabilitation

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    Development of techniques for measuring the mobility of knee joints in children with Cerebral Palsy

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    Cerebral Palsy, commonly referred to as CP, is a neurological disorder that results in loss or impairment of motor function, which affects body movement, muscle control, muscle coordination and balance. In Sweden, about 200 children are diagnosed with Cerebral Palsy every year and the disorder can cause imbalances between the muscles. These imbalances can lead to contractures which is equiva- lent to permanent shortening of muscles and stiffness of joints. This can severely affect the mobility of the child and the quality of life. Today, the only way for physicians or physiotherapists to evaluate the movement of the joints, is during a patient’s short visits to the hospital. The purpose of this project was to develop a device that was able to measure the range of motion of the knee during a longer period of time, which could help customize the child’s rehabilitation. The initial approach was to implement two inertial measurement units (IMUs) and find the angle between the sensors. Different solutions on finding the angle was tested without being able to obtain stable data and the project members chose a new approach. Instead of IMUs, a potentiometer was used and stable data was obtained. A prototype was developed in an iterative and incremental product development process and data was collected during different types of physical exercise. The final prototype was wireless, able to collect data during ordinary life activities and had a battery life of over 30 hours. The data was analyzed and the results were accurate but showed that the prototype probably hindered some of the natural movement of the knee. The developed prototype is a step towards being able to measure the knee range of motion during a longer period of time, and could be a tool for physicians and other medical staff when evaluating and rehabilitating children with CP.Utveckling av mätteknik för mätning av rörligheten i knäleder hos barn med Cerebral pares Cerebral pares (CP) är en neurologisk störning som kan leda till förlust eller nedsättning av de motoriska funktioner som påverkar kroppens rörelser, muskelkontroll, koordination och balans. CP kan orsaka obalanser mellan musklerna som kan leda till kontrakturer. Kontrakturer innebär att musklerna förkortas permanent och styvheten i lederna ökar. Muskelförkortning och styva leder kan drastiskt påverka barnets rörlighet och därmed även livskvaliteten. I Sverige diagnostiseras cirka 200 barn varje år med CP och i dagsläget är det enda sättet för läkaren eller fysioterapeuten att utvärdera barnens rörelsefunktion under kortare besök på sjukhuset, 1-2 gånger per år. Därför var syftet med detta projekt att utveckla en prototyp som kunde mäta knäets ledrörlighet under en längre period
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