Method for predicting ball launch conditions

Abstract

A method and computer program for predicting a golfer's ball striking performance is disclosed. In order to generate a predicted trajectory and predicted ball launch conditions, it is desirable to determine several properties of the golf equipment and a player's swing. For instance, pre-impact swing conditions of a golfer are observed using a monitoring system. Additionally, it is desirable to determine the properties of the golf ball and golf club. Moreover, the effect of the shaft properties and the slippage between the golf club and the golf ball may also be considered. In this manner, a more accurate determination of a golfer's predicted trajectory and ball launch conditions may be determined without requiring the golfer to actually strike a golf ball.

1 . A method for predicting a golfer's ball striking performance, comprising: 
 determining a plurality of pre-impact swing properties for the golfer based on the golfer's swing with a golf club, the plurality of pre-impact swing properties including an impact location, an orientation of a golf club head, and the golf club head speed;    determining a plurality of equipment properties including a plurality of golf ball properties and plurality of golf club properties, the plurality of golf ball properties including a coefficient of restitution at a plurality of velocities and a time of contact at a plurality of velocities, and the plurality of club properties including a center of mass of the club head, a center of a club face, and a moment of inertia;    determining the slippage between the golf club and the golf ball based on the plurality of ball properties, the plurality of club properties, and the plurality of pre-impact swing properties; and    generating a predicted trajectory and a plurality of predicted ball launch conditions of the golf ball if struck with the golf club based on the slippage, the plurality of equipment properties, and the plurality of pre-impact swing properties.    
   
   
       2 . The method according to  claim 1 , further comprising determining the properties of a shaft of the golf club on the impact of the golf ball with the club head, the properties of the shaft including a longitudinal force component and a torque component.  
   
   
       3 . The method according to  claim 1 , wherein the determining the slippage comprises determining a first slip period between the golf club and the golf ball, a stick period between the golf club and the golf ball, and a second slip period between the golf club and the golf ball.  
   
   
       4 . The method according to  claim 3 , wherein the determining the slippage comprises computing each time step in the first slip period, the stick period, and the second slip period in microsecond time intervals.  
   
   
       5 . The method according to  claim 4 , wherein the computing each time step is based on a transverse force of the golf ball, a coefficient of friction of the golf ball, and a normal force of the golf ball.  
   
   
       6 . The method according to  claim 1 , wherein the predicted trajectory includes at least one of distance, flight path, landing position, and final resting position.  
   
   
       7 . The method according to  claim 1 , wherein the plurality of predicted ball launch conditions includes at least one of side spin, back spin, rifle spin, azimuth angle, launch angle, and velocity.  
   
   
       8 . A method for predicting a golfer's ball striking performance, comprising: 
 determining a plurality of pre-impact swing properties for the golfer based on the golfer's swing with a golf club, the plurality of pre-impact swing properties including an impact location, an orientation of a golf club head, and the golf club head speed;    determining a plurality of equipment properties including a plurality of golf ball properties and plurality of golf club properties, the plurality of golf ball properties including a coefficient of restitution at a plurality of velocities and a time of contact at a plurality of velocities, and the plurality of club properties including a center of mass of the club head, a center of a club face, and a moment of inertia;    determining the effect of properties of a shaft of the golf club on the impact of the golf ball with the club head, the properties of the shaft including a longitudinal force component and a torque component; and    generating a predicted trajectory and a plurality of predicted ball launch conditions of the golf ball if struck with the golf club based on the properties of the shaft, the plurality of equipment properties, and the plurality of pre-impact swing properties.    
   
   
       9 . The method according to  claim 8 , further comprising determining the slippage between the golf club and the golf ball based on the plurality of ball properties, the plurality of club properties, and the plurality of pre-impact swing properties.  
   
   
       10 . The method according to  claim 8 , wherein the properties of the shaft further includes at least one of a shear force, a bending moment, density, shear modulus, and Young's modulus.  
   
   
       11 . The method according to  claim 8 , wherein the determining the slippage comprises determining a first slip period between the golf club and the golf ball, a stick period between the golf club and the golf ball, and a second slip period between the golf club and the golf ball.  
   
   
       12 . The method according to  claim 8 , wherein the predicted trajectory includes at least one of distance, flight path, landing position, and final resting position.  
   
   
       13 . The method according to  claim 8 , wherein the plurality of predicted ball launch conditions includes at least one of side spin, back spin, rifle spin, azimuth angle, launch angle, and velocity.  
   
   
       14 . The method according to  claim 11 , wherein the determining the slippage comprises computing each time step in the first slip period, the stick period, and the second slip period in microsecond time intervals.  
   
   
       15 . The method according to  claim 8 , further comprising: 
 modifying at least one of the plurality of equipment properties;    generating another predicted trajectory and another plurality of predicted ball launch conditions of the golf ball if struck with the golf club based on the at least one modified equipment property.    
   
   
       16 . The method according to  claim 15 , wherein the plurality of equipment properties comprises the golf club center of mass, the golf club weight distribution, the center of the golf club face, the moment of inertia of the golf club, and the friction coefficient of the golf club face.  
   
   
       17 . The method according to  claim 15 , wherein the modifying comprises using one or more different golf balls.  
   
   
       18 . A method for predicting a golfer's ball striking performance, comprising: 
 determining a plurality of pre-impact swing properties for the golfer based on the golfer's swing with a golf club, the plurality of pre-impact swing properties including an impact location, an orientation of a golf club head, and the golf club head speed;    determining a plurality of equipment properties including a plurality of golf ball properties and plurality of golf club properties, the plurality of golf ball properties including a coefficient of restitution at a plurality of speeds, and a time of contact at a plurality of speeds, and the plurality of club properties including a center of mass of the club head, a center of a club face, and a moment of inertia;    determining the slippage between the golf club and the golf ball based on the plurality of ball properties, the plurality of club properties, and the plurality of pre-impact swing properties;    determining the effect of properties of a shaft of the golf club on the impact of the golf ball with the club head, the properties of the shaft including a longitudinal force component and a torque component; and    generating a predicted trajectory and a plurality of predicted ball launch conditions of the golf ball if struck with the golf club based on the slippage, the plurality of equipment properties, and the plurality of pre-impact swing properties.    
   
   
       19 . The method according to  claim 18 , wherein the determining the slippage comprises determining a first slip period between the golf club and the golf ball, a stick period between the golf club and the golf ball, and a second slip period between the golf club and the golf ball.  
   
   
       20 . The method according to  claim 18 , wherein the properties of the shaft further includes at least one of shear force, a bending moment, density, shear modulus, and Young's modulus.