ABSTRACT
To conduct a 3-dimensional trajectory analysis of a golf ball, a 3-dimension equation of motion of a ball in flight was formulated. The trajectory equation of a ball in flight was obtained under two assumptions of (1) the mechanism of slices or hooks of a ball is caused by an inclining of the ball rotating axis and (2) the direction given to the rotating axis of the ball is constant. On the other hand, a device to rotate an actual golf ball stably at a maximum of 10,000 rev/min was developed. By this, drag, dynamic lift, aerodynamic momentum (aerodynamic forces) applied on the ball under various flight conditions were measured in a wind tunnel air current.
Using these aerodynamic force coefficients, mathematical calculation of flight trajectory equation was made by time integral calculus, and 3-dimensional flight trajectory, changes in velocity as well as rotation velocity were obtained. Ejection experiments were made using a robot and flight distance and side deviation distance were obtained. The validity of the theory was verified by comparing the calculation results with the experiment results.
