RESUMEN
The present study aims at designing and evaluating a low-cost, simple and portable system for arm joint angle estimation during grasping-like motions. The system is based on a single RGB-D camera and three customized markers. The automatically detected and tracked marker positions were used as inputs to an offline inverse kinematic process based on bio-mechanical constraints to reduce noise effect and handle marker occlusion. The method was validated on 4 subjects with different motions. The joint angles were estimated both with the proposed low-cost system and, a stereophotogrammetric system. Comparative analysis shows good accuracy with high correlation coefficient (r= 0.92) and low average RMS error (3.8 deg).
Asunto(s)
Articulaciones/fisiología , Movimiento , Fotogrametría/economía , Fotogrametría/instrumentación , Adulto , Brazo/fisiología , Fenómenos Biomecánicos , Femenino , Fuerza de la Mano , Humanos , Masculino , Programas Informáticos , Interfaz Usuario-ComputadorRESUMEN
The objective of this paper is to present a new paradigm in control strategy for unsupported paraplegic standing, based on closed-loop control of paraplegics' lower extremities. The main advantage of our approach is taking into account voluntary motions of the upper-part of the body by controlling Center of Mass (CoM) position. The validity of our approach is tested, in computer simulations, using human CoM trajectories estimated from experimental data and by applying perturbations in simulation during quiet standing in order to simulate voluntary upper body movements. From the results presented in this study it can be seen that controller is able to track desired CoM position with sufficient precision and to maintain stability even in the presence of simulated movements of the upper body.
Asunto(s)
Simulación por Computador , Extremidad Inferior/fisiopatología , Modelos Biológicos , Movimiento , Paraplejía/fisiopatología , Postura , Adulto , Femenino , Humanos , MasculinoRESUMEN
Sound translation into neural message at the first auditory synapse is of prime importance for providing organism with sound environment. Here, we compiled experimental features of the primary auditory neurons into a computational model, composed of two distinct compartments (i.e., afferent bouton and axon). Simulation of the model closely reproduces the whole biophysical properties of both excitatory post-synaptic currents and action potentials firing. This simple model provides a powerful tool to understand the synaptic disorders on the sound neural coding at the first auditory synapse.