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Abstract-In order to study the effects of aging on biomechanics properties, twenty rabbits with healthy eyes were divided into four groups including infancy (3 months), youth (5 months), midlife (18 months) and agedness (48 months). After measuring the central corneal thickness (CCT) and the intraocular pressure (IOP), the alteration of eye volume with intraocular pressure was determined of four different...
In this paper, the influence of the finger posture on the subjective effort during pinching motion is investigated by using a tendon-skeletal finger model. The experimental results show that the subjective effort human feels is affected by the size of the object he/she pinches, and the subjective effort correlates with the finger length. The simulation results show that the pattern of the tendon forces...
An abled individual is believed to be capable of withstanding and overcoming the severe tremors of an earthquake as has been ascertained in a previous study. However, the event-related physiological mechanisms of human postural stability during an earthquake are subject to further investigation. Accordingly, the objective of this study is to further characterize postural stability in a simulated environment...
A reliable predictor of drowsiness using objective measures is desirable for machine and vehicle operations in which human errors may cause fatal accidents. We have evaluated the Vestibulo-Ocular Reflex (VOR) as a possible predictor of drowsiness. The VOR is a compensatory eye movement that stabilizes retinal image during head motion, and is inevitably induced by vibration in a car running on the...
The balance between human body composition, e.g. bones, muscles, and fat, is a major and basic indicator of personal health. This paper proposes a new discrimination method for measuring the thickness of subcutaneous fat and muscular layers based on tissue elasticity. The validity of the proposed method was evaluated in twenty-one subjects (twelve women, ten men; aged 20-70 yr) at three anatomical...
In this study, we tried to discriminate the direction of arm force from hemoglobin concentration changes measured by near-infrared spectroscopy (NIRS). A self-organizing map (SOM) was used to classify the force direction information obtained from the NIRS signals. In a human subject experiment, the subjects were required to perform isometric arm movements in four directions. We investigated the feature...
This paper presents a scientific strategy for cycling induced by the functional electrical stimulation. In order to simulate the FES-cycling movement produced by human body, a neuro-musculo-skeletal model containing 16 segments and 186 muscles is developed, which can simulate human movements precisely. This model contains mathematical model of electrically stimulated skeletal muscles. Having known...
This paper proposes a method of estimating fingertip forces in finger tapping movements based on human fingerpad characteristics. Since the human fingerpad exhibits elasticity, the proposed technique recreates the relationship between the fingertip force and the displacement generated between the thumb and index fingerpads as a fingerpad-stiffness model. Then, using this model, the force between the...
This paper presents a novel in vitro dental wear simulator based on 6-6 parallel kinematics to replicate mechanical wear formation on dental materials and components, such as individual teeth, crowns or bridges. The human mandible, guided by a range of passive structures moves with up to six degrees of freedom (DOF). Currently available wear simulators lack the ability to perform these complex chewing...
In this study, a single tri-axial accelerometer placed on the waist was used to record the acceleration data for human physical activity classification. The data collection involved 24 subjects performing daily real-life activities in a naturalistic environment without researchers' intervention. For the purpose of assessing customers' daily energy expenditure, walking, running, cycling, driving, and...
Passive translation of the body in space elicits a complex combination of directionally-specific torques that are exerted on the neck. The inertial torques that are produced by linear translation are counteracted by linear vestibular and proprioceptive reflexes that maintain head stability. A novel experimental apparatus was used in this study to translate human subjects in a random and unpredictable...
In this paper, we describe a novel wireless system to facilitate the objective assessments of neurological movement disorders like dyskinesia. The ability of the prototype system to provide precise, objective biomechanical data about human motor performance has been demonstrated via controlled tests using a robotic arm. The system is designed to be used in clinical settings and will not require an...
Normal human locomotion requires the ability to control a complex, redundant neuromechanical system to repetitively cycle the legs in a stable manner. In a reduced paradigm of locomotion, hopping, we investigated the ability of human subjects to exploit motor redundancy in the legs to coordinate joint torques fluctuations to minimize force fluctuations generated against the ground. Although we saw...
This paper presents a numerical approach using principal component analysis (PCA) to quantize and characterize the variance of hand postures in a novel posture transformation task. Five subjects were tested in two tasks in which a cursor can be moved by varying the hand posture. This was accomplished by weighted linear combination of 14 sensors of a data glove. The first task was to move a cursor...
Ergometric exercise stress tests (EST) give important information about the cardiovascular (CV) response to increased demands. The expected EST-related changes in variables like blood pressure and heart rate are known, but those in the arterial biomechanics are controversial and incompletely characterized. Aims: a) to characterize the regional and local arterial biomechanical behavior in response...
The high incidence of concussion in contact sports provides a unique opportunity to collect data to characterize mild traumatic brain injury. This paper outlines a macro to micro approach in which the organ level response of the head is analyzed through head acceleration data from human volunteers and the tissue level response is analyzed through finite element analysis of these data. The helmets...
The objective of this research is to explore whether a two-dimensional BCI can be achieved by reliably decoding single-trial magneto-encephalography (MEG) signal associated with sustaining or ceasing right and left hand movements. Seven naiumlve subjects participated in the study. Signals were recorded from 275-channel MEG and synthetic aperture magnetometry (SAM) was employed. The multi-class classification...
Recent experimental evidence suggests that a fundamental property of the human motor system is that it ldquoslacksrdquo; that is, that it continuously attempts to decrease levels of muscle activation when movement error is small during repetitive motions. This paper reviews several computational models of slacking, and discusses implications of slacking for the design of robotic orthoses. For therapeutic...
Robotic lower limb exoskeletons have been built for augmenting human performance, assisting with disabilities, studying human physiology, and re-training motor deficiencies. At the University of Michigan Human Neuromechanics Laboratory, we have built pneumatically-powered lower limb exoskeletons for the last two purposes. Most of our prior research has focused on ankle joint exoskeletons because of...
We undertake the study of the chaotic nature of mechanomygraphy (MMG) signal by recourse to the recent developments in the field of nonlinear dynamics. The MMG signals were measured from biceps brachii muscle of 5 subjects during fatigue of isometric contraction at 80% maximal voluntary contraction (MVC) level. Deterministic chaotic character was detected in all data by using the Volterra-Wiener-Korenberg...
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