RESUMEN
Wearable electronics are playing an important role in the health care industry. Wearable sensors are either directly attached to the body surface or embedded into worn garments. Textile-based batteries can help towards development of body conformal wearable sensors. In this letter, we demonstrate a 2D planar textile-based primary Ag2O-Zn battery fabricated using the stencil printing method. A synthetic polyester woven fabric is used as the textile substrate and polyethylene oxide material is used as the separator. The demonstrated battery achieves an areal capacity of 0.6 mAh/cm2 with an active electrode area of 0.5 cm × 1 cm.
Asunto(s)
Dispositivos Electrónicos Vestibles , Suministros de Energía Eléctrica , Plata , Textiles , ZincRESUMEN
Pneumatic muscle actuators (PMAs) have a high power to weight ratio and possess unique characteristics which make them ideal actuators for applications involving human interaction. PMAs are difficult to control due to nonlinear dynamics, presenting challenges in system implementation. Despite these challenges, PMAs have great potential as a source of resistance for strength training and rehabilitation. The objective of this work was to control a PMA for use in isokinetic exercise, potentially benefiting anyone in need of optimal strength training through a joint's range of motion. The controller, based on an inverse three-element phenomenological model and adaptive nonlinear control, allows the system to operate as a type of haptic device. A human quadriceps dynamic simulator was developed (as described in Part I of this work) so that control effectiveness and accommodation could be tested prior to human implementation. Tracking error results indicate that the control system is effective at producing PMA displacement and resistance necessary for a scaled, simulated neuromuscular actuator to maintain low-velocity isokinetic movement during simulated concentric and eccentric knee extension.
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Ejercicio Físico/fisiología , Músculos/fisiología , Entrenamiento de Fuerza/instrumentación , Tacto , Fenómenos Biomecánicos , Simulación por Computador , Humanos , Actividad Motora , Factores de Tiempo , TorqueRESUMEN
Pneumatic muscle actuators (PMAs) have a high power to weight ratio and possess unique characteristics which make them ideal actuators for applications involving human interaction. PMAs are difficult to control due to nonlinear dynamics, presenting challenges in system implementation. Despite these challenges, PMAs have great potential as a source of resistance for strength training and rehabilitation. The objective of this work was to control a PMA for use in isokinetic exercise, potentially benefiting anyone in need of optimal strength training through a joint's range of motion. A human quadriceps dynamic simulator (HQDS) was developed so that control effectiveness and accommodation could be tested prior to human implementation. The experimental set-up and HQDS are discussed in Part I of this work. The development of a PMA haptic controller and its interaction with the HQDS are discussed in Part II.
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Músculo Cuádriceps/fisiología , Entrenamiento de Fuerza/instrumentación , Humanos , Articulación de la Rodilla/fisiología , Modelos Biológicos , Rango del Movimiento ArticularRESUMEN
INTRODUCTION: A pneumatic muscle actuator (PMA) is a device that mimics the behavior of skeletal muscle by contracting and generating force when activated. This type of actuator has a high power to weight ratio and unique characteristics which make it ideal for human interaction. PMAs, however, are difficult to control due to nonlinear dynamics. Our objective was to control a PMA as a source of task-specific resistance in simulated isokinetic strength training. Task-specific resistance will benefit those in need of strength training through a joint's range of motion, including astronauts who need to counteract muscle atrophy during prolonged spaceflight. The lightweight, clean, and compact PMA driven by pressurized air is able to produce resistance in microgravity. METHODS: An open-loop control method based on a three-element phenomenological inverse model was developed to control the PMA. A motor was simultaneously controlled to act as simulated human quadriceps working against the PMA-produced resistance. RESULTS: For ankle weight replacement resistance profiles, the PMA control method produced resistance and PMA displacement tracking errors (RMSE) of 0.36-1.61 Nm and 0.55-1.59 mm, respectively. Motor position (simulated joint angle) tracking errors ranged from 0.47 to 2.82 degrees. DISCUSSION: Results indicate that the inverse model based control system produces task-specific PMA resistance and displacement. Closed-loop motor control was able to simulate isokinetic movement successfully. More complicated resistance profiles reveal the need for closed-loop control. Future work focuses on advancing both the PMA control strategies and the capabilities of the human simulator so that actual human operator applications can be realized.