Gait Analysis
Mohsen Sadeghi Mehr; Davoud Naderi; Nader Farahpour; Saeed Davoud Abadi Farahani
Volume 3, Issue 3 , June 2009, , Pages 179-187
Abstract
The present study was devoted to determine the standing human body reactions to perturbation of a base plate in the frontal plane, in order to preserve its stability. A base plate with sinusoidal fluctuation was designed and built and then markers were mounted on the specified locations on it and the ...
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The present study was devoted to determine the standing human body reactions to perturbation of a base plate in the frontal plane, in order to preserve its stability. A base plate with sinusoidal fluctuation was designed and built and then markers were mounted on the specified locations on it and the skin of subjects before testing. During testing the subjects (N=10) tried to preserve their stability against perturbations. By using Motion Analysis System, the body responses of subjects were analyzed. Using inverse dynamic methods and experimental kinematic results, forces and moments applied to the joints and between feet soles and the base plate were determined. In theoretical study, the kinematic and dynamic equations of motion of a robotic model of human body in frontal plane by using repetitive Newton-Euler method were obtained. Based on the stability of the model and supporting vertical forces criterion an object function was defined, in order to assure the stability of the model. By optimization of the object function, angle of the model joints under perturbation and its first and second derivatives were determined. The good agreement of the theoretical and experimental results states that in similar conditions a robotic model can be used instead of expensive and time-consuming experiments.
Neuro-Muscular Engineering
Davoud Naderi; Mohsen Sadeghi Mehr; Nader Farahpour; Behnam Miripour-Fard
Volume 2, Issue 2 , June 2008, , Pages 85-93
Abstract
Cognition of human postural responses can provide valuable insight on the control of stability. Researchers can use this finding to design rehabilitation exercises to improve the patients, balance. This study was done with the aim of conducting theoretical and experimental investigations on human response ...
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Cognition of human postural responses can provide valuable insight on the control of stability. Researchers can use this finding to design rehabilitation exercises to improve the patients, balance. This study was done with the aim of conducting theoretical and experimental investigations on human response to tilting base plate in the sagittal plane. A four-segment model with three degrees of freedom was used as a biomechanical model of human body and its motion was studied in the sagittal plane. The postures of model were found by optimization technique such that the stability of model to be optimum. Zero moment point stability criterion was applied to find the optimum posture against the tilting base plate. To verify the theoretical results experimentally, the stability measure device was designed and manufactured. In several trials, the responses of ten male healthy persons standing on a tilting platform under perturbations were recorded by using the motion analysis system. Through data analysis, the response of each subject was surveyed and the experimental and theoretical results were compared. Both the experimental and theoretical results showed that the human central nervous system evokes the ankle strategy to keep its balance under tilting base plate conditions. A good coincident between the experimental results and theoretical predictions was observed, indicating that the model basis optimization method can be well relied upon to predict the human joints angle trajectories in response to base plate tilting.
