Abstract
The purpose of this study was to quantify the dynamical role of joint torques in control of racket face orientation during badminton smash motion. The human body was modeled as a multi-linked segment model consisting of 17 rigid segments with 38 DOFs of joints. The racket shaft was divided into a set of rigid segments connecting to its adjacent segments via virtual joints with rotational springs and damper. The joint angle and angular velocity of the shaft joints were calculated using generalized velocity vectors and the time integration of the velocity vector. The contributions of joint axial torques to the angular velocity of racket face were calculated from the equation of motion for a racket-human combined system. In order to realize stable numerical calculation for stiff system, the Newmark-beta method was used at the computation of recurrent equation. From the results, shoulder horizontal adduction/abduction and sternocleidal horizontal adduction/abduction joint torques significantly contributed to the racket face angular velocity. These torques were the great contributor for controlling racket orientation during badminton jump smash motion.
