Golf ball trajectory computing system and method of computing trajectory of golf ball

• US 20050215338A1
• Filed: 03/29/2005
• Published: 09/29/2005
• Est. Priority Date: 03/29/2004
• Status: Abandoned Application

• Current Assignee: Yokohama Rubber Company Limited
• Original Assignee: Yokohama Rubber Company Limited
• Inventors: Miyamoto, Masahiko
• Application Number:
  US11/091,779
• Publication Number:
  US 20050215338A1
• Time in Patent Office: Days
• US Class Current: 473/155
• CPC Class Codes: A63B 2024/0031 at the starting point
• CPC Class Codes: A63B 2024/0037 on a target surface or at impact on the ground
• CPC Class Codes: A63B 2220/35 Spin
• CPC Class Codes: A63B 24/0021 Tracking a path or terminating locations
• CPC Class Codes: A63B 69/3658 Means associated with the ball for indicating or measuring, e.g. speed, direction

Abstract

A trajectory of a struck golf ball from when the golf ball is struck until the golf ball lands is computed by a golf ball trajectory computing system. The system comprises: an initial trajectory measuring portions that measures an initial velocity, a launch angle, and a backspin rate of the golf ball immediately after impact thereof; a carry distance measuring portion that measures a carry distance of the golf ball from an impact point to a landing point where the golf ball lands; a duration-of-flight measuring portion that measures a duration of flight of the golf ball from impact thereof until the golf ball lands; and a computing portions that computes a trajectory of the golf ball based on the measured initial velocity, the measured launch angle, and the measured backspin of the golf ball immediately after impact, and the carry distance and the duration of flight of the golf ball.

Claims

1. A golf ball trajectory computing system that computes a trajectory of a struck golf ball from when the golf ball is struck until the golf ball lands, comprising:

initial trajectory measuring portion that measures an initial velocity, a launch angle, and a backspin rate of the golf ball immediately after impact thereof;

carry distance measuring portion that measures a carry distance of the golf ball from an impact point to a landing point where the golf ball lands;

duration-of-flight measuring portion that measures a duration of flight of the golf ball from impact thereof until the golf ball lands; and

computing portion that computes a trajectory of the golf ball based on the measured initial velocity, the measured launch angle, and the measured backspin of the golf ball immediately after impact, and the carry distance and the duration of flight of the golf ball.

2. The golf ball trajectory computing system according to claim 1, wherein said computing portion computes an average drag coefficient and an average lift coefficient for the golf ball during flight from the initial velocity of the golf ball, the launch angle, and the backspin rate immediately after impact, and from the carry distance and the duration of flight, and computes the trajectory of the golf ball using the computed average drag coefficient and the computed average lift coefficient.

3. The golf ball trajectory computing system according to claim 1, wherein said computing portion computes the trajectory of the golf ball using equations of motion of the golf ball, and sets an average drag coefficient and an average lift coefficient so that the carry distance and the duration of flight computed by using the equations of motion of the golf ball match the carry distance measured by said carry distance measuring portion and the duration of flight measured by said duration-of-flight measuring portion, respectively, within a predetermined error range.

4. A method of computing a trajectory of a golf ball, comprising:

measuring an initial velocity, a launch angle, and a backspin rate of the golf ball immediately after the golf ball is struck;

measuring a carry distance of the golf ball from an impact point to a landing point where the golf ball lands;

measuring the duration of flight of the golf ball from impact thereof until the golf ball lands; and

computing the trajectory of the golf ball based on the initial velocity, the launch angle, and the backspin rate of the golf ball immediately after impact thereof, based on the carry distance and the duration of flight.

5. The method of computing the trajectory of a golf ball according to claim 4, wherein said computing of the trajectory of the golf ball further comprises computing an average drag coefficient and an average lift coefficient of the golf ball during flight from the initial velocity, the launch angle, and the backspin rate of the golf ball immediately after impact thereof, and from the carry distance and the duration of flight, and computing the trajectory of the golf ball using the computed average drag coefficient and the computed average lift coefficient.

6. The method of computing the trajectory of a golf ball according to claim 5, wherein said computing of the trajectory of the golf ball further comprises:

setting an initial value of the average drag coefficient and an initial value of the average lift coefficient of the golf ball during flight;

finding a computed value of the carry distance and a computed value of the duration of flight of the golf ball based on the initial value of the average drag coefficient and the initial value of the average lift coefficient;

comparing the computed value of the carry distance and the computed value of the duration of flight with the measured value of the carry distance and the measured value of the duration of flight, respectively; and

based on results of said comparing, computing an average drag coefficient and an average lift coefficient of the golf ball during flight, so that the computed value of the carry distance and the computed value of the duration of flight of the golf ball fall within a predetermined error range with respect to the measured value of the carry distance and the measured value of the duration of flight, by adjusting at least one of the initial value of the average drag coefficient and the initial value of the average lift coefficient.