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A neural network (NN) control system is designed for the functional electrical stimulation (FES) assisted standing up. A musculoskeletal model of nine muscles and three segments is constructed for the simulation study. Each muscle is controlled by the sub-network of the functional neural network. The sub-network is the radial basis function (RBF) NN. Minimal resource allocation (M-RAN) learning algorithm...
Static and dynamic manipulation of objects with the fingertips (precision pinch) is essential to the activities of daily living. Despite numerous efforts to study the hand and its pinch function, a comprehensive understanding of biomechanical function and neuromuscular control of the fingers eludes researchers. To make progress in understanding precision pinch we are creating biomechanical models...
This work presents the design of a mechanical vasoconstriction mechanism with application for cerebral autoregulation. The relationship between the applied voltage of a DC motor and the tension within a pressurized vessel wall was utilized for constricting an arteriole segment within an intracranial vascular model. Using current proportional to the string tension, options for closed loop feedback...
Research and development in various fields dealing with human movement has been hampered by the lack of adequate software tools. We have formed a core development team to organize a collective effort by the research community to develop musculoskeletal modeling software that satisfies the requirements of both researchers and clinicians. We have identified initial requirements and have developed some...
The authors propose a method to transform the motor impedance from the end-point into the joint. The central nervous system regulates the mechanical impedance of the end-point through the muscle and joint, which requires this kind of transformation of the motor impedance. It is shown that the redundancy of the musculoskeletal system allows selection of the impedance of each joint in order to maintain...
The author assesses the validity of three models dealing with human arm trajectory control by evaluating their success in accounting for the kinematic characteristics of planar horizontal unconstrained point-to-point arm trajectories. These models are concerned with two significant issues. Namely, in what coordinate frame(s) are movements internally represented by the brain and, how intention is translated...
One of the goals of human walking is to produce safe foot trajectories which end in gentle foot placements. The authors present a computer simulation that uses internal models and feedforward control laws to explain anticipatory behavior exhibited by subjects during obstructed walking. A hierarchical structure allows present mechanical behavior to be adapted in advance of future mechanical requirements...
An eighth-order nonlinear Hill-based muscle-joint model is used with a global optimization scheme to study normal-to-fast single-joint movement strategies. The optimization criterion includes measures of neuromuscular effort and dynamic performance of the movement. By systematically varying the relative weights of such competing criteria as position error and neural or muscle effort, a continuum of...
A control model is presented which is based on exhaustive biomechanical and EMG analyses of human gait. The motor patterns (moments-of-force, mechanical power and EMG), when compared over a wide range of cadences and subjects, gives the author considerable insight into strategies used by the central nervous system. The net result of these analyses is the identification of three fairly independent...
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