ゴルフスイングのリリースポイントに関する動力学解析（クラブおよび人間の諸元の影響）

抄録

We aim to clarify the mechanism of the release point of the golf swing and the effect of the parameters of a club and a human body on dynamic behavior at the release point. First, the mathematical model of the golf swing is assumed to be a 2-dimensional double pendulum connected with a nonlinear rotational spring at the wrist joint. By applying Lagrange's equation to this system, we derive equations of motion of the golf swing. We consider that the wrist joint begins to turn naturally under the centrifugal force of the swing. When the angular velocity of the arm and the centrifugal force become to be sufficiently large compared to the angular acceleration and tangential inertial force, uncocking begins naturally without driving torque applied to the wrist joint. We derive simple approximate equations which express the relationship between angular velocity and acceleration at the release point. By using the derived equations and the equations of motion , we also derive some expressions demonstrating the effect of the parameters of a golf club on the dynamic behavior at the release point which may affect significantly on the head speed by using new modeling method, and calculation and discussion are carried out on the effect of the parameters of the club , the cock angle and the active wrist torque on the release point. Through the discussion, it can be seen that the derived simple approximate equations give us physical insight of the phenomena at the release point and help us to understand the effect of the club parameters on the dynamic behavior of the double pendulum at the release point.