Low power glove for hand functioning analysis in children with cerebral palsy

In this paper, a low-cost glove has been manufactured to monitor and analyse the hand motion for the children who suffer from the cerebral palsy. Cerebral palsy (CP) is a combination of continual disorders affect the movement’s evolution due to a non-gradual disturbance in developing fetal or infant cerebrum. An Arduino Nano microcontroller with flex and force sensors are attached to soft cloth glove to form the analysis glove. The data of this study is collected from children who have cerebral palsy, non-cerebral palsy, and children who are treating by physiotherapy and then compared with each other. The results show that the analysis glove helps the physiotherapist to assess the hand functioning problem such as difficulty in hand grip and inability to fully bend the hand figures in general and thumb figure in particular. These remarks can help physiotherapists to define the required program to improve these functions and indications

Motion capture technology in industrial applications: A systematic review

The rapid technological advancements of Industry 4.0 have opened up new vectors for novel industrial processes that require advanced sensing solutions for their realization. Motion capture (MoCap) sensors, such as visual cameras and inertial measurement units (IMUs), are frequently adopted in industrial settings to support solutions in robotics, additive manufacturing, teleworking and human safety. This review synthesizes and evaluates studies investigating the use of MoCap technologies in industry-related research. A search was performed in the Embase, Scopus, Web of Science and Google Scholar. Only studies in English, from 2015 onwards, on primary and secondary industrial applications were considered. The quality of the articles was appraised with the AXIS tool. Studies were categorized based on type of used sensors, beneficiary industry sector, and type of application. Study characteristics, key methods and findings were also summarized. In total, 1682 records were identified, and 59 were included in this review. Twenty-one and 38 studies were assessed as being prone to medium and low risks of bias, respectively. Camera-based sensors and IMUs were used in 40% and 70% of the studies, respectively. Construction (30.5%), robotics (15.3%) and automotive (10.2%) were the most researched industry sectors, whilst health and safety (64.4%) and the improvement of industrial processes or products (17%) were the most targeted applications. Inertial sensors were the first choice for industrial MoCap applications. Camera-based MoCap systems performed better in robotic applications, but camera obstructions caused by workers and machinery was the most challenging issue. Advancements in machine learning algorithms have been shown to increase the capabilities of MoCap systems in applications such as activity and fatigue detection as well as tool condition monitoring and object recognition

Design and Evaluation of a Customized and Body-powered Prosthesis using Fingertip Trajectories based on Polar Coordinate Analysis

Department of Mehcanical EngineeringThis thesis presents a design and evaluation of a customized finger prosthesis that generates a natural finger motion. The design of the prosthesis followed two primary requirements: i) the size of the prosthesis should reflect that of an amputee???s finger; ii) the prosthesis should enable the natural finger motion of the amputee. To achieve these aims, two methods were employed: i) an incomplete four-bar mechanism by utilizing the remaining joint of a subject as the joint in the mechanism; ii) a fingertip trajectory analysis in polar coordinates to model the natural finger motion as only one degree of freedom (DOF). A serially connected incomplete four-bar mechanism was applied to create an under-actuation system. The under-actuation system operated by a metacarpophalangeal (MCP) joint rotation of the amputee which makes proximal interphalangeal (PIP) and distal interphalangeal (DIP) joint rotations. The system does not need any actuators to control the two joint rotations, but employs the residuum of the amputee as an actuator. The fingertip trajectory was considered as the typical factor to represent the natural finger motion, and a new curve fitting method in the polar coordinate of the fingertip trajectory was proposed. The method represents not only the finger motion of a single subject but also of people in general using the same order equation. To make the proposed mechanism move like the natural finger motion of the amputee, a fingertip trajectory curve from the curve fitting method was used as a reference for the mechanism in an optimization process. During the optimization process, the design variables were chosen by considering data from the finger amputee (e.g. residuum size, expected phalangeal lengths, etc.) as well as the requirements of the finger prosthesis. A modular wearable interface was proposed to allow the system to be worn easily and the system joint to be manually aligned to the finger joint accurately. As we focused on the design of the finger prosthesis, the prototype was manufactured based on the finger information of a normal subject before applying it to the actual finger amputee. The performance of the proposed system was verified by intensive experiments for grasping and manipulation while wearing the proposed system.clos

Development of a wearable sensing glove for measuring the motion of fingers using linear potentiometers and flexible wires

In this paper, a wearable sensing glove for measuring the motion of the fingers is proposed. The system consists of linear potentiometers, flexible wires, and linear springs, which makes it compact and lightweight so that it does not interfere with the natural motion of the fingers. Inspired by the way wrinkles on finger joints are smoothed out when the finger is flexed, a flexible wire is attached to the back of each finger. As the flexible wire moves due to the motion of the finger, the joint angles are calculated by measuring the change in length of wire. Linear potentiometers with linear springs were used to maintain the tension of the wires in order to measure the wire length change consistently. Because the motion of the proximal interphalangeal (PIP) joint is dependent on that of the distal interphalangeal (DIP) joint, only two linear potentiometers were used for each finger. A compact sensing module including 10 linear potentiometers and springs was attached to a glove. The proposed system can widely be applied for the systems, which require to measure finger motions accurately, e.g., virtual reality or teleoperation systems. Such feasible applications were actually implemented and introduced in this paper.close0

Sistema de miografia óptica para reconhecimento de gestos e posturas de mão

Orientador: Éric FujiwaraDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia MecânicaResumo: Nesse projeto, demonstrou-se um sistema de miografia óptica como uma alternativa promissora para monitorar as posturas da mão e os gestos do usuário. Essa técnica se fundamenta em acompanhar as atividades musculares responsáveis pelos movimentos da mão com uma câmera externa, relacionando a distorção visual verificada no antebraço com a contração e o relaxamento necessários para dada postura. Três configurações de sensores foram propostas, estudadas e avaliadas. A primeira propôs monitorar a atividade muscular analisando a variação da frequência espacial de uma textura de listras uniformes impressa sobre a pele, enquanto que a segunda se caracteriza pela contagem de pixels de pele visível dentro da região de interesse. Ambas as configurações se mostraram inviáveis pela baixa robustez e alta demanda por condições experimentais controladas. Por fim, a terceira recupera o estado da mão acompanhando o deslocamento de uma série de marcadores coloridos distribuídos ao longo do antebraço. Com um webcam de 24 fps e 640 × 480 pixels, essa última configuração foi validada para oito posturas distintas, explorando principalmente a flexão e extensão dos dedos e do polegar, além da adução e abdução do último. Os dados experimentais, adquiridos off-line, são submetidos a uma rotina de processamento de imagens para extrair a informação espacial e de cor dos marcadores em cada quadro, dados esses utilizados para rastrear os mesmos marcadores ao longo de todos os quadros. Para reduzir a influência das vibrações naturais e inerentes ao corpo humano, um sistema de referencial local é ainda adotado dentro da própria região de interesse. Finalmente, os dados quadro a quadro com o ground truth são alimentados a uma rede neural artificial sequencial, responsável pela calibração supervisionada do sensor e posterior classificação das posturas. O desempenho do sistema para a classificação das oito posturas foi avaliado com base na validação cruzada com 10-folds, com a câmera monitorando o antebraço pela superfície interna ou externa. O sensor apresentou uma precisão de ?92.4% e exatidão de ?97.9% para o primeiro caso, e uma precisão de ?75.1% e exatidão de ?92.5% para o segundo, sendo comparável a outras técnicas de miografia, demonstrando a viabilidade do projeto e abrindo perspectivas para aplicações em interfaces humano-robôAbstract: In this work, an optical myography system is demonstrated as a promising alternative to monitor hand posture and gestures of the user. This technique is based on accompanying muscular activities responsible for hand motion with an external camera, and relating the visual deformation observed on the forearm to the muscular contractions/relaxations for a given posture. Three sensor designs were proposed, studied and evaluated. The first one intended to monitor muscular activity by analyzing the spatial frequency variation of a uniformly distributed stripe pattern stamped on the skin, whereas the second one is characterized by reckoning visible skin pixels inside the region of interest. Both designs are impracticable due to their low robustness and high demand for controlled experimental conditions. At last, the third design retrieves hand configuration by tracking visually the displacements of a series of color markers distributed over the forearm. With a webcam of 24 fps and 640 × 480 pixels, this design was validated for eight different postures, exploring fingers and thumb flexion/extension, plus thumb adduction/abduction. The experimental data are acquired offline and, then, submitted to an image processing routine to extract color and spatial information of the markers in each frame; the extracted data is subsequently used to track the same markers along all frames. To reduce the influence of human body natural and inherent vibrations, a local reference frame is yet adopted in the region of interest. Finally, the frame by frame data, along with the ground truth posture, are fed into a sequential artificial neural network, responsible for sensor supervised calibration and subsequent posture classification. The system performance was evaluated in terms of eight postures classification via 10-fold cross-validation, with the camera monitoring either the underside or the back of the forearm. The sensor presented a ?92.4% precision and ?97.9% accuracy for the former, and a ?75.1% precision and ?92.5% accuracy for the latter, being thus comparable to other myographic techniques; it also demonstrated that the project is feasible and offers prospects for human-robot interaction applicationsMestradoEngenharia MecanicaMestre em Engenharia Mecânica33003017CAPE

Application of memristors in realization of microwave passive circuits

Предмет истраживања ове докторске дисертације је примјена мемристора у реализацији планарних микроталасних пасивних кола. У фокусу истраживања је микроталасни помјерач фазе остварен коришћењем мемристивних прекидача. Истраживање обухвата и реализацију микроталасних филтара са мемристорима. Циљ истраживања је реализација микроталасног помјерача фазе који има боље карактеристике у односу на карактеристике одговарајућих помјерача фазе објављених у доступној отвореној литератури, а који користе традиционалне прекидаче као што су PIN диоде, микроелектромеханички прекидачи и CMOS. Такође, циљ истраживања представља и анализа могућих реализација микроталасних филтара коришћењем мемристора. Доприноси дисертације су нов метод пројектовања помјерача фазе, коришћењем мемристора, а којим се смањује потрошња уређаја и поправља константност фазног помјераја у специфицираном фреквенцијском опсегу. При реализацији филтара, коришћењем мемристора потиснути су нежељени пропусни опсези, реализован је реконфигурабилни филтар коришћењем мемристивних прекидача. Поред тога, пројектован је хардвер за аутоматско програмирање комерцијално доступног мемристора компаније KnowM, развијен је алгоритам и софтвер микроконтролера који омогућава аутоматско програмирање, као и софтвер преносивог или удаљеног уређаја за контролу рада микроконтролера. Пројектована су електрична кола остварена коришћењем комерцијално доступног мемристора. Предложен је модел за фреквенцијску анализу комерцијално доступног мемристора на учестаностима до 1 MHz. Пројектован је активни филтар пропусник опсега, који има могућност подешавања централне фреквенције при радном режиму. За експерименталну верификацију рада програматора и електричних кола направљени су лабораторијски прототипови.The scope of the research presented in this doctoral dissertation is the application of memristors in the realization of planar microwave passive circuits. The focus of the research was the microwave phase shifter realized using memristive switches. In addition, the research includes the realization of microwave filters by incorporating memristors. The aim of the research is the realization of a microwave phase shifter with better characteristics compared to the characteristics of phase shifters available in the open literature, which use traditional switches like PIN diodes, microelectromechanical systems, and CMOS. Also, the aim of the research is the analysis of microwave filters with incorporated memristors. The contribution of the doctoral dissertation is a novel method of designing microwave phase shifters - by using memristors which reduces the power consumption of the device and improves the constancy of the phase shift in the specified frequency range. By using memristors in the realization of filters, unwanted bandwidths are suppressed, and a reconfigurable filter is realized by using memristive switches. In addition, hardware for the automatic programming of KnowM's commercially available memristors has been designed, an algorithm and microcontroller software that enables automatic programming have been developed, as well as software for a portable or remote device to control the operation of the microcontroller. Electrical circuits designed using the commercially available memristor were realized. A frequency analysis model of the commercially available memristor at frequencies of up to 1 MHz has been proposed. An active bandpass filter has been designed, which has the ability to tune the center frequency during operation. Laboratory prototypes were made for the experimental verification of the operation of programmers and electrical circuits

An investigation of the Matteucci effect on amorphous wires and its application to bend sensing

The study of wearable sensors for human biometrics has recently developed into an important research area due to its potential for personalised health monitoring. To measure bending parameters in humans such as joint movement or posture, several techniques have been proposed however, the majority of these suffer from poor accuracy, sensitivity and linearity. To overcome these limitations, this research aims to develop a novel flexible sensor for the measurement of bending by utilising the Matteucci effect on amorphous wires. The Matteucci effect occurs in all ferromagnetic wires but the advantages of amorphous wires are their superior soft magnetic and magnetoelastic properties and a Matteucci effect that is very sensitive to applied stresses like tensile and torsion. For these reasons a sensor based on Matteucci effect was investigated for use as a wearable bending sensor. Previous studies of the Matteucci effect have been interpreted in terms of simple phenomenological models using conveniently sized lengths of amorphous wire. In this work, the Matteucci effect has been characterised in short, sensor-compatible, wires. In addition, a thorough examination of the stress dependency of the Matteucci effect was also investigated as this is an area that has been neglected in the past. The main aim of this work was to study the effect of tensile and torsion stresses on the Matteucci effect in both highly positive magnetostrictive and nearly zero magnetostrictive amorphous wires. A measurement rig was specifically built to characterise the Matteucci effect for a range of magnetic field amplitudes, frequencies, torsions and axial stresses. The second major aim was to use this characterisation data to ascertain the optimum working parameters to design and construct a novel flexible bending sensor. In this work, the Matteucci effect in amorphous wires was found to be very sensitive to both axial and torsional applied stresses and dependent upon the sign of the magnetostriction. Insights gained here were used to develop the bend sensor in three steps. The initial prototype was a non-flexible strain sensor for measuring tensile stress and exhibited a very high gauge factor equal to 601± 30. The second step resulted in a strain sensor prototype utilising a flexible planar coil to magnetise the amorphous wire. The final step produced a bend sensor this time consisting of a flexible solenoid with greater magnetising capability. It resulted in a bend sensor IV with a high output voltage sensitivity of 5.62 ± 0.02 mV/cm which is the slope of the voltage due to curvature and excellent linearity (R2 = 0.98). In this case the sensor’s operating range was 1.11 rad to 2.49 rad with ± 0.003 rad uncertainty. This range is scalable and dependent on the sensor configuration. This work has demonstrated the feasibility of utilising the Matteucci effect as a bend sensor with a performance exceeding that found in many commercial sensors