Browsing by Author "Dugarte, Nelson"

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    Diseño de control tipo joystick para vehículos eléctricos como scooter y sillas de ruedas motorizadas
    (2021-01-01) Dugarte, Nelson; Alvarez, Antonio; Alvarado, Negman; Dugarte, Edinson; Ozahl, Álvaro
    Este artículo trata sobre el diseño de un mando de control electrónico utilizable en vehículos motorizados para personas con movilidad reducida. El instrumento desarrollado consta de dos partes, un hardware electrónico y un software de control. El hardware del prototipo consiste en un circuito electrónico diseñado para controlar la velocidad del vehículo por medio de un joystick miniatura tipo gamer. Esto permite el manejo del aparato con pequeños movimientos y mínimo esfuerzo por parte del paciente. El algoritmo del software es implementado en una tarjeta programable Arduino tipo UNO. Permite el control de dos motores eléctricos de corriente continua (DC) normalmente utilizados en mecanismos de tracción de sillas de ruedas eléctricas y en scooter destinados a personas discapacitadas. La salida del Arduino maneja la velocidad de giro de los motores por medio de un circuito electrónico que limita la potencia utilizando la técnica de modulación del ancho del pulso (PWM). La novedad del sistema consiste en el desarrollo de tecnología propia, donde se incorporan mejoras como la posibilidad de viraje angular pronunciado, que permite al usuario comandar el aparato en espacios reducidos, típicos de los ambientes domésticos comunes. Las pruebas preliminares demostraron la eficiencia del sistema. El instrumento se encuentra actualmente en proceso de prueba y certificación en los laboratorios del Instituto Regional de Bioingeniería (IRB) de la Universidad Tecnológica Nacional (UTN) Facultad Regional Mendoza (FRM).
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    ECG Multilead QT interval estimation using support vector machines
    (2019-01-01) Dugarte, Nelson
    This work reports a multilead QT interval measurement algorithm for a high-resolution digital electrocardiograph. The software enables off-line ECG processing including QRS detection as well as an accurate multilead QT interval detection algorithm using support vector machines (SVMs). Two fiducial points ( and ) are estimated using the SVM algorithm on each incoming beat. This enables segmentation of the current beat for obtaining the P, QRS, and T waves. The QT interval is estimated by updating the QT interval on each lead, considering shifting techniques with respect to a valid beat template. The validation of the QT interval measurement algorithm is attained using the Physionet PTB diagnostic ECG database showing a percent error of with respect to the database annotations. The usefulness of this software tool is also tested by considering the analysis of the ECG signals for a group of 60 patients acquired using our digital electrocardiograph. In this case, the validation is performed by comparing the estimated QT interval with respect to the estimation obtained using the Cardiosoft software providing a percent error of .
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    High efficiency and simple technique for controlling mechanisms by EMG signals.
    (2015-01-01) Dugarte, Nelson; Alvarez, Antonio; Mercado, Gustavo; González, Adolfo; Dugarte, Edinson
    This article reports the development of a simple and efficient system that allows control of mechanisms through electromyography (EMG) signals. The novelty about this instrument is focused on individual control of each motion vector mechanism through independent electronic circuits. Each of electronic circuit does positions a motor according to intensity of EMG signal captured. This action defines movement in one mechanical axis considered from an initial point, based on increased muscle tension. The final displacement of mechanism depends on individual's ability to handle the levels of muscle tension at different body parts. This is the design of a robotic arm where each degree of freedom is handled with a specific microcontroller that responds to signals taken from a defined muscle. The biophysical interaction between the person and the final positioning of the robotic arm is used as feedback. Preliminary tests showed that the control operates with minimal positioning error margins. The constant use of system with the same operator showed that the person adapts and progressively improves at control technique.
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    High efficiency processing for reduced amplitude zones detection in the HRECG signal.
    (2015-01-01) Dugarte, Nelson; Alvarez, Antonio; Balacco, José; Mercado, Gustavo; Dugarte, Edinson
    This article presents part of a more detailed research proposed in the medium to long term, with the intention of establishing a new philosophy of electrocardiogram surface analysis. This research aims to find indicators of cardiovascular disease in its early stage that may go unnoticed with conventional electrocardiography. This paper reports the development of a software processing which collect some existing techniques and incorporates novel methods for detection of reduced amplitude zones (RAZ) in high resolution electrocardiographic signal (HRECG).The algorithm consists of three stages, an efficient processing for QRS detection, averaging filter using correlation techniques and a step for RAZ detecting. Preliminary results show the efficiency of system and point to incorporation of techniques new using signal analysis with involving 12 leads.
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    Practical design of flow meter for mechanical ventilation equipment
    (2021-04-01) Dugarte, Nelson; Alvarez, Antonio; Dugarte, Edison; Alvarado, Negman; Bhaskar, Sonu
    This paper introduces a practical technique for the design of an instrument used in air flow measurement or flowmeter. This instrument is an essential component in the hospital medical ventilation equipment functioning, therefore, the parameters design presented in this article focus on this purpose. However, this instrument can be employed to any measurement scale. The technique is based on indirect flow measurement, using a sensor that converts the flow parameter into a differential pressure measurement. An electronic transducer allows the differential pressure values to be obtained as an electrical signal, which is then digitized and analyzed to obtain the original parameter. The experimental procedure presented in this paper utilizes a computational algorithm to perform the signal analysis; however, given the simplicity of the procedure, this could be adapted to any digital processing card or platform, to show the measurement obtained immediately. Preliminary analyses demonstrated instrument efficiency with sensitivity of 0.0681 liters per second (L/s). Accuracy evaluation showed an average measurement error lesser than 1.4%, with a standard deviation of 0.0612 and normal distribution over the set of test measurements.