647 research outputs found

    Powered Transtibial Prosthetic Device Control System Design, Implementation and Testing

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    A powered lower limb prosthesis, which consists of a four bar mechanism, a torsional spring and a brushed DC motor, was previously designed and fabricated. To regulate the motor power input, a two level controller was proposed and built. The control algorithm includes a higher level finite state controller and lower level PID controllers. To implement the control system, a digital signal processor (DSP) control board and MATLAB Simulink were used to realize the higher level control and a DC motor controller was used to realize the lower level PID control. Sensors were selected to provide the required feedback. The entire control system was implemented on a convenient to carry backpack. Amputee subject testing was performed to obtain some experimental verification of the design. The results showed that the control system performed consistently with the designed control algorithm and did assist in the amputee’s walking. Compared to a currently available powered prosthesis, this control is simple in structure and able to mimic the nonlinear behavior of the ankle closely

    Accuracy Improvement of Neural Networks Through Self-Organizing-Maps over Training Datasets

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    Although it is not a novel topic, pattern recognition has become very popular and relevant in the last years. Different classification systems like neural networks, support vector machines or even complex statistical methods have been used for this purpose. Several works have used these systems to classify animal behavior, mainly in an offline way. Their main problem is usually the data pre-processing step, because the better input data are, the higher may be the accuracy of the classification system. In previous papers by the authors an embedded implementation of a neural network was deployed on a portable device that was placed on animals. This approach allows the classification to be done online and in real time. This is one of the aims of the research project MINERVA, which is focused on monitoring wildlife in Do˜nana National Park using low power devices. Many difficulties were faced when pre-processing methods quality needed to be evaluated. In this work, a novel pre-processing evaluation system based on self-organizing maps (SOM) to measure the quality of the neural network training dataset is presented. The paper is focused on a three different horse gaits classification study. Preliminary results show that a better SOM output map matches with the embedded ANN classification hit improvement.Junta de Andalucía P12-TIC-1300Ministerio de Economía y Competitividad TEC2016-77785-

    Nuevo dispositivo para análisis de voz de pacientes con enfermedad de Parkinson en tiempo real

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    RESUMEN: La enfermedad de Parkinson (EP) es un desorden neurodegenerativo que afecta la coordinación de músculos y extremidades, incluyendo aquellos responsables de la producción del habla, generando alteraciones en la inteligibilidad de la señal de voz. Está demostrado que el ejercicio terapéutico constante puede mejorar las habilidades de comunicación de los pacientes; sin embargo, el diagnóstico acerca del avance en el proceso de recuperación es realizado de forma subjetiva por los fonoaudiólogos o neurólogos. Debido a esto se requiere el desarrollo de herramientas flexibles que valoren y guíen la terapia fonoaudiológica de los pacientes. En este artículo se presenta el diseño e implementación de un sistema embebido para el análisis en tiempo real de la voz de pacientes con EP. Para esto se desarrollan tres plataformas; primero, se construye una interfaz gráfica en Matlab; luego, se crea un primer prototipo basado en un DSP TMS320C6713 de Texas Instruments. La aplicación final es desarrollada sobre un mini-ordenador que cuenta con un códec de audio, capacidad de almacenamiento, y una unidad de procesamiento. El sistema además se complementa con un monitor LCD para desplegar información en tiempo real, y un teclado para la interacción con el usuario. En todas las plataformas se evalúan diferentes medidas usadas comúnmente en la valoración de la voz de pacientes con EP, incluyendo características acústicas y de dinámica no lineal. En concordancia con otros trabajos del estado del arte donde se analiza la voz de personas con EP, la plataforma diseñada muestra un incremento en la variación del pitch en la voz de los pacientes, además de un decremento en el valor del área del espacio vocálico. Este resultado indica que la herramienta diseñada puede ser útil para hacer la evaluación y seguimiento de la terapia fonoaudiológica de pacientes con EP.ABSTRACT: Parkinson’s disease (PD) is a neurodegenerative disorder that affects the coordination of muscles and limbs, including those responsible of the speech production. The lack of control of the limbs and muscles involved in the speech production process can generate intelligibility problems and this situation has a negative impact in the social interaction of the patients. It is already demonstrated that constant speech therapy can improve the communication abilities of the patients; however, the measurement of the recovery progress is done subjectively by speech therapists and neurologists. Due to this, it is required the development of flexible tools able to asses and guide the speech therapy of the patients. In this paper the design and deployment of a new device for the real time assessment of speech signals of people with PD is presented. The processes of design and deployment include the development on three platforms: first, a graphic user interface is developed on Matlab, second the first prototype is implemented on a digital signal processor (DSP) and third, the final device is developed on a mini-computer. The device is equipped with an audio codec, storage capacity and the processing unit. Besides, the system is complemented with a monitor to display the processed information on real time and with a keyboard enabling the interaction of the end-user with the device. Different acoustics and nonlinear dynamics measures which have been used in the state of the art for the assessment of speech of people with PD are implemented on the three mentioned platforms. In accordance with the state of the art, the designed platforms show an increment in the variation of the fundamental period of speech (commonly called pitch) of people with PD. Additionally, the decrease of the vocal space area is validated for the case of patients with PD. These results indicate that the designed device is useful to perform the assessment and monitoring of the speech therapy of people with PD

    Principal Component Analysis of Gait Kinematics Data in Acute and Chronic Stroke Patients

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    We present the joint angles analysis by means of the principal component analysis (PCA). The data from twenty-seven acute and chronic hemiplegic patients were used and compared with data from five healthy subjects. The data were collected during walking along a 10-meter long path. The PCA was applied on a data set consisting of hip, knee, and ankle joint angles of the paretic and the nonparetic leg. The results point to significant differences in joint synergies between the acute and chronic hemiplegic patients that are not revealed when applying typical methods for gait assessment (clinical scores, gait speed, and gait symmetry). The results suggest that the PCA allows classification of the origin for the deficit in the gait when compared to healthy subjects; hence, the most appropriate treatment can be applied in the rehabilitation

    A Technical Framework for Musical Biofeedback in Stroke Rehabilitation

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    Design and simulation analysis of an improved lower limb exoskeleton

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    The lower extremity exoskeleton robot is a type of power assisted robot which can enhance the human walking function. A fundamental problem in the development of the exoskeleton is the choice of lightweight actuators. Thus in the mechanical structure design in this paper, the linear motor is selected as it greatly reduces the complexity of the mechanical structure. Furthermore, the limit switch inside the motor improves the safety performance. Based on the last version of the exoskeleton, the band positions, length adjusting holes and mechanical limit structures are increased. In addition, a control system based on DSP is designed. Furthermore, a kinematics analysis is carried out using the D-H parameter method and a dynamic analysis is developed using the Newton-Euler method. The driving force of every joint is obtained during the simulation using ADAMS software

    Active hip orthosis for assisting the training of the gait in Hemiplegics

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    The gait restoration is a significant component of the rehabilitation of patients with hemiplegia after central nervous system lesion. The typical symptom of the disability is the lack of hip extension during the stance phase and hip flexion during the swing phase of the affected leg; therefore, asymmetry and perturbed balance while walking. We developed a new modular orthosis for assisting hip flexion and extension during the therapeutic sessions of the gait in hemiplegic individuals based on thorough analysis of the gait characteristics of normal gait. The system is designed to fit into the powered postural controller Walkaround®. The system is developed based on the estimation of torque and power requirement for the gait at speeds up to 1.1 m/s. The model used for the simulation is a known double pendulum in the sagittal plane. The kinematics and dynamics used as the input for the simulation have been recorded in the gait laboratory with eight cameras and force platforms. The system needs to be clinically evaluated before it possibly can be turned into innovation. © 2018, University of Kragujevac, Faculty of Science

    Ultrasonic Doppler Sonar Sensor System for Extraction of Walk Signatures

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    In this work, a portable low cost sensor system is designed for the extraction of walking signatures in humans using the principle of Ultrasonic Doppler Sonar (UDS). UDS involves the use of two ultrasonic transducers acting as a transmitter-receiver pair. The transmitter produces a continuous ultrasonic signal at a specific frequency to be broadcasted onto a moving target, while the receiver will perform a frequency shift on the reflected signal in relation to the movement of the target. The sensor system used in this work is comprised of a frequency generator that drives the transducer with a 40 kHz sine wave and a data acquisition device. Signal processing methods were implemented on the received data to extract and analyze the Doppler features of a human walk. Data was initially collected using a function generator which produced the transmitted 40 kHz signal together with Measurement Computing WaveBook-516E data acquisition measurement hardware. To make the system portable, the design was simplified using the National Instruments USB-6216 Data Acquisition (DAQ) for both the transmitted signal and saving the received sampled data. The WaveView data acquisition software was used to control the WaveBook DAQ while a LabView program was written to interface with the NI USB-6216 hardware. The primary objective of implementing the sensor system is to automate the data collection without the use of a computer, which the use of NI data acquisition made possible, but the system parts were expensive and needed the use of a laptop to manage the process. A microprocessor, together with an Analog to Digital Converter (ADC) and a Digital to Analog Converter (DAC), were tested for generating the driving transmitting signal and the collection of the data. The TI C6748 digital signal processors on the Texas Instruments OMAP-L138 Development Kit was the chosen processor as it is a floating-/fixed-point DSP with up to 456 MHz clock speed, the access to standard interfaces on the development kit, and the availability of software development kits, drivers, and algorithm libraries for fast development
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