Determination of Cylindrical Power Grip Motion by Modeling and Surface Electromyography

Nowadays most of workers use hand controller tools in their industrial work situations. Since musculoskeletal disorders of upper extremities are believed to be associated with repetitive excessive hand tools using, understanding the one of these relations between hand and tools as cylindrical power grip is essential for exploring the mechanism of disease development. In this study, first of all, a device that measure torque of gripping entitled’ gripping device’, has been made in a biomechanical laboratory. Secondary by using a musculoskeletal model, the gripping motion of upper limb was investigated. But due to kinematic indeterminacy of the assumed model, the values of joint angels has been calculated using optimization method and evaluating optimum values based on joint limit avoidance criteria. After that, using Newton method, and applying genetic algorithm as optimization method, the inverse kinetic problem of the model has been solved. Then obtained muscle’s forces, produced because of external gripping moment, were normalized. Finally by using electromyography test device, the activity of three upper and lower limb surface muscles of random people has been investigated to compare them by results of activity coefficient which are obtained from modeling.