Inexpensive and Portable System for Dexterous High-Density Myoelectric Control of Multiarticulate Prostheses

Multiarticulate bionic arms are now capable of mimicking the endogenous movements of the human hand. 3D-printing has reduced the cost of prosthetic hands themselves, but there is currently no low-cost alternative to dexterous electromyographic (EMG) control systems. To address this need, we developed an inexpensive (~$675) and portable EMG control system by integrating low-cost microcontrollers with an EMG acquisition device. We validated signal acquisition by comparing the signal-to-noise ratio (SNR) of our system with that of a high-end research-grade system. We also demonstrate the ability to use the low-cost control system for proportional and independent control of various prosthetic hands in real-time. We found that the SNR of the low-cost control system was statistically no worse than 44% of the SNR of a research-grade control system. The RMSEs of predicted hand movements (from a modified Kalman filter) were typically a few percent better than, and not more than 6% worse than, RMSEs of a research-grade system for up to six degrees of freedom when only relatively few (six) EMG electrodes were used. However, RMSEs were generally higher than RMSEs of research-grade systems that utilize considerably more (32) EMG electrodes, guiding future work towards increasing electrode count. Successful instantiation of this low-cost control system constitutes an important step towards the commercialization and wide-spread availability of dexterous bionic hands.Comment: IEEE EMBC 202

Device for assisting rehabilitation of the knee skeletal muscle

gráficos, tablasLa respuesta de los músculos en el movimiento durante actividades de la vida diaria y algunas de sus características ---fuerza, agilidad y resistencia--- pueden verse afectadas luego de una lesión, enfermedad o cirugía. Esas alteraciones no tienen tratamiento médico y la rehabilitación es la única opción para devolver la funcionalidad en las extremidades. El profesional de la salud debe establecer un plan de rehabilitación teniendo en cuenta las dimensiones biológica, social y psicológica del paciente, de acuerdo con la ICF. Como parte del plan, debe ser cuantificado frecuentemente el impacto de la terapia en la funcionalidad, determinando progreso o retroceso. Aunque la APTA establece la necesidad de medir la evolución del paciente, la evolución se establece por observación directa del profesional de la salud usualmente, considerando rangos y velocidad de movimiento y dolor percibido. Sin embargo, algunas sesiones se realizan en casa, lo que dificulta el seguimiento del paciente y cuantificar el impacto del plan de rehabilitación. Esta situación se acentúa cuando el paciente no tiene acceso directo a profesionales de la salud debido al lugar donde vive. En este trabajo se desarrolla un dispositivo para asistir la rehabilitación de rodilla. Para tal fin, se desarrolla un sistema de medida inercial y un módulo para la medición de las señales de electromiografía. Aunque en la literatura especializada se pueden encontrar desarrollos que buscan asistir la terapia física, algunos requieren de equipos especializados y no pueden ser usados en casa. Por otro lado, los desarrollos propuestos para ser aplicados en ese entorno carecen de módulos para la evolución del desempeño muscular. Esta medida es valiosa para los terapeutas para establecer cambios en el plan de rehabilitación. Como resultados se presenta el desarrollo de un dispositivo con una baja relación costo-efectividad. Entre los resultados se encuentra el desarrollo de un soporte con el que se busca mejorar la repetibilidad en la ubicación de los electrodos. Entre los trabajos futuros se encuentra la incorporación del dispositivo en un sistema de asistencia y la optimización del firmware para aprovechar las características de los componentes electrónicos. En ese contexto, se incluye el desarrollo de estrategias para informar al paciente y al profesional de la salud sobre el desempeño en las sesiones de terapia. Otros trabajos podrían incluir algoritmos que permitan identificar si el paciente realiza algún tipo de compensación con otras estructuras corporales mientras realiza los ejercicios. (Texto tomado de la fuente)The reaction of muscles in movement during activities of daily living and some of their characteristics---strength, agility and endurance---can be affected after injury, disease or surgery. These alterations have no medical treatment, and rehabilitation is the only option to restore limb function. According to the ICF, healthcare practitioneers must establish a rehabilitation plan considering the patient's biological, social and psychological dimensions. As part of the plan, the impact of therapy on functionality should be quantified frequently, determining progress or regression. Although the APTA establishes the need to measure the patient's evolution, it is usually established by direct observation by the healthcare professional, considering ranges and speed of movement and perceived pain. However, some sessions are performed at home, which makes it difficult to follow the patient and quantify the impact of the rehabilitation plan. This situation is accentuated when the patient does not have direct access to health professionals due to the place where the patient lives. In this work is presented the develop of a to assist knee rehabilitation. For this purpose, an inertial measurement system and a module for measuring electromyography signals are developed. Although in the specialized literature can be found developments that seek to assist physical therapy, some of them require specialized equipment and cannot be used at home. On the other hand, the developments proposed to be applied in that environment lack modules for the evolution of muscle performance. This measure is valuable for therapists to establish changes in the rehabilitation plan. As results, the development of a device with a low cost-effectiveness ratio is presented. Among the results, the development of a support that seeks to improve the repeatability in the location of the electrodes is ilustrated. Future work includes the incorporation of the device in an assistance system and the optimization of the firmware to take advantage of the characteristics of the electronic components. The development of strategies to inform the patient and the healthcare professional about performance in therapy sessions is included. Further work could also consider algorithms to identify whether the patient performs any compensation with other body structures while performing the exercises.MaestríaMagíster en Ingeniería - Automatización IndustrialTecnologías asistivasEléctrica, Electrónica, Automatización Y Telecomunicacione

Inexpensive and Portable System for Dexterous High-Density Myoelectric Control of Multiarticulate Prostheses

Multiarticulate bionic arms are now capable of mimicking the endogenous movements of the human hand. 3D-printing has reduced the cost of prosthetic hands themselves, but there is currently no low-cost alternative to dexterous electromyographic (EMG) control systems. To address this need, we developed an inexpensive (~675) and portable EMG control system by integrating low-cost microcontrollers with a six-channel surface EMG (sEMG) acquisition device. Using this low-cost control system, we quantify, in a pilot study, the performance of a common EMG-based control algorithm-the modified Kalman filter (MKF)-when computational resources and electrode count are limited. We also demonstrate the ability to provide proportional and independent control of various six-degree-of-freedom prosthetic hands in real-time using the MKF. We found no significant differences in the signal-to-noise ratio (SNR) of the low-cost control system and that of a high-end research-grade system (paired t-tests). We also found no significant difference in the Root Mean Squared Errors (RMSEs) of predicted hand movements for the low-cost control system and that of the research-grade system when using only six sEMG electrodes. We then demonstrate that the SNR of the low-cost control system is statistically no worse than 44% of the SNR of the research-grade system (equivalence tests). Likewise, we demonstrate that RMSEs were typically a few percent better than, and statistically not more than 6% worse than, RMSEs of a research-grade system. This held true even when controlling up to six degrees of freedom on a prosthetic hand. Despite minimal computational resources and only six sEMG electrodes, the system performs satisfactorily and highlights the practicality and efficiency of the modified Kalman filter for dexterous EMG-based control. Successful deployment of this low-cost control system constitutes an important step towards the commercialization and wide-spread availability of dexterous bionic hands