Dynamic Analysis of Golf Swing

(Discussion of Mechanism of Wrist Turn Using Modal Analysis)

Abstract

We aim to clarify dynamics of the wrist turn of golf swing and the effect of the parameters on dynamic behavior at the wrist turn using the double pendulum model and modal analysis. Eigenvalue analysis was carried out for the linearized two-degree-of-freedom system and natural frequency and mode were calculated. We found out that the first mode is a rigid mode and the second one is the vibration mode of the double pendulum, and mode shapes are constant during the wrist turn even though natural frequency changes. By applying the modal analysis method we obtained equations of motion for the rigid mode and vibration mode separately. Furthermore, using the theory of linear superposition, the equation of motion for the vibration mode was separated again into 3 equations which can help to understand the mechanism of the wrist turn. Calculation results for shallow cock angle by the proposed modal separation method and the exact solution using numerical integration for the double pendulum compared well and showed the validity of the proposed method. The effect of the parameters of the arm torque and the wrist torque on the dynamic behavior of the wrist turn were examined by the parameter survey using the proposed method and the mechanism of the wrist turn was clarified.