Open Access

ARTICLE

Modeling of Muscle Force at Varied Joint Angles of the Human Arm and Estimation of Gripping Force Using Surface EMG

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1 Department of Mechanical Engineering,Visvesvaraya National Institute of Technology,Nagpur ( MS) 440010 India.
Email : cmsbpl@gmail.com,tusharkulkarni@students.vnit.ac.in Mobile no. : +917767044760
2 Department of Mechanical Engineering,Visvesvaraya National Institute of Technology, Nagpur ( MS) 440010 India. Email : rashmiu71@gmail.com, rvuddanwadikar@mec.vnit.ac.in Mobile no. :+919881239509

Molecular & Cellular Biomechanics 2016, 13(2), 87-104. https://doi.org/10.3970/mcb.2016.013.099

Abstract

This paper aims to determine the force required for holding the objects by human hand. A static analysis is performed on mathematical models to obtain holding force considering lower arm as class three lever and by varying the joint angles. Three mathematical models are discussed to quantify the force required to hold any object, for different weight of the object and the joint angles. A noninvasive experimentation using surface electromyogram was performed to determine the forces required by human hand for the same objects used in the mathematical modeling. Twenty-one male subjects participated in this test and were asked to hold different objects. EMG signals were recorded and converted into grip force in Newton. The EMG to Force conversion was accomplished by the equation derived from the Hills model. The experimentation revealed that subjects in the age group of 20-50 years generated more grip force as compared to those above the age of fifty years. The values of muscle force obtained from the experimentation are optimum values which depend upon the nature of the gripping habits subjects are used to. Whereas, in the case of mathematical models yielded maximum force required to sustain the weight placed on the hand considering it as a mechanical system. The study revealed an average gripping force of 85 Newton required to hold the objects weighing between 0.015 kg to 1.18 kg used in the experimentation. The mathematical model resulted in an average of 162 Newton muscle force to hold the object having similar weights.

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