Myoelectric control algorithm for robot-assisted therapy: a hardware-in-the-loop simulation study.

BACKGROUND: A direct blow to the knee is one way to injure the anterior cruciate ligament (ACL), e.g., during a football or traffic accident. Robot-assisted therapy (RAT) rehabilitation, simulating regular walking, improves walking and balance abilities, and extensor strength after ACL reconstruction. However, there is a need to perform RAT during other phases of ACL injury rehabilitation before attempting an advanced exercise such as walking. This paper aims to propose a myoelectric control (MEC) algorithm for a robot-assisted rehabilitation system, "Nukawa", to assist knee movement during these types of exercises, i.e., such as in active-assisted extension exercises. METHODS: Surface electromyography (sEMG) signal processing algorithm was developed to detect the motion intention of the knee joint. The sEMG signal processing algorithm and the movement control algorithm, reported by the authors in a previous publication, were joined together as a hardware-in-the-loop simulation to create and test the MEC algorithm, instead of using the actual robot. EXPERIMENTS AND RESULTS: An experimental protocol was conducted with 17 healthy subjects to acquire sEMG signals and their lower limb kinematics during 12 ACL rehabilitation exercises. The proposed motion intention algorithm detected the orientation of the intention 100% of the times for the extension and flexion exercises. Also, it detected in 94% and 59% of the cases the intensity of the movement intention in a comparable way to the maximum voluntary contraction (MVC) during extension exercises and flexion exercises, respectively. The maximum position mean absolute error was [Formula: see text], [Formula: see text], and [Formula: see text] for the hip, knee, and ankle joints, respectively. CONCLUSIONS: The MEC algorithm detected the intensity of the movement intention, approximately, in a comparable way to the MVC and the orientation. Moreover, it requires no prior training or additional torque sensors. Also, it controls the speed of the knee joint of Nukawa to assist the knee movement, i.e., such as in active-assisted extension exercises.

SISTEMA DE TOCOCARDIOGRAFÍA DIGITAL CON PROCESAMIENTO EN UNA FPGA PARA EL MONITOREO MATERNO-FETAL / DIGITAL CARDIOTOCHOGRAPHY SYSTEM WITH PARALLEL FPGA PROCESSING FOR MATERNAL FETAL MONITORING / SISTEMA DE TOCOCARDIOGRAFÍA DIGITAL COM PROCESSAMENTO EM UM FPGA PARA MONITORAMENTO MATERNO-FETAL

El estudio clínico fetal relaciona aspectos críticos como la intensidad de las contracciones uterinas, movimientos del feto y frecuencia cardiaca de manera simultánea para evaluar el bienestar fetal. Los cambios periódicos o transitorios de la frecuencia cardiaca son objeto de estudio y aparecen en relación a diversos estímulos fetales como movimientos espontáneos o provocados, contracciones uterinas, hipo fetal, etc. Con este propósito, en una valoración de los mismos es necesario disponer de una constante monitorización, en la que se exprese la frecuencia y la variabilidad cardiaca fetal de manera eficiente. En este artículo se presenta el desarrollo de un sistema de tococardiografía para el registro de la frecuencia cardiaca fetal y la intensidad de las contracciones uterinas compuesto por tres tarjetas electrónicas, una unidad de procesamiento digital paralela, una campana acústica y una pantalla para adquirir y procesar de manera no invasiva las señales tococardiográficas.

Clinical evaluation on fetuses is related to simultaneous critical aspects such as intensity of uterine contractions, fetal movements, and heart rate. Periodic or transient changes in heart rate are studied and appear in relation to various fetal stimuli as spontaneous or induced movements, uterine contractions, fetal hiccups, and so on. Thus, their evaluation is necessary to obtain constant monitoring in which the frequency and variability are expressed efficiently. This paper presents the development of a cardiotochography system for recording fetal heart rate and intensity of uterine contractions, which is composed by three electronic boards, a digital parallel processing unit, a sounds bell and a screen to acquire non-invasively and process tococardiography’s signals.

O estudo clinico fetal relaciona aspectos críticos, como a intensidade das contrações uterinas, movimentos fetais e batimentos cardíacos simultaneamente para avaliar o bem-estar fetal. As mudanças periódicas ou transitórias da frequência cardíaca são estudados e aparecem em relação a vários movimentos fetais espontâneas ou induzidas, as contrações uterinas, soluços fetais, etc. Para este efeito, em uma revisão do mesmo é necessário ter monitoramento constante, na que se exprese a freqüência e variabilidade do ritmo cardíaco fetal de forma eficiente. Este artigo é apresentado o desenvolvimento de um sistema de tococardiografía para registar o ritmo cardíaco fetal e intensidade das contrações uterinas composto por três placas eletrônicas, uma unidade de processamento digital paralelo, uma cabine acústica e uma tela para adquirir e processar de maneira não invasiva as sinais tococardiográficas.