(R.W. Madden, May 1941)
Recently, the Sports Biomechanics Laboratory
completed two projects concerning baseball aerodynamics. The first
project determined the initial conditions of the baseball pitch.
The second, uses these initial conditions to duplicate the pitch
with a pitching machine.
Initial Condition Determination
Completed 06/18/1998.
Primary Researcher - LeRoy Alaways
The focus of this project was the determination of the effect
that angular velocity has on the trajectory of the pitched baseballs.
This was accomplished by estimating the initial conditions (position,
translational velocity, and angular velocity) of the pitch by constructing
an accurate aerodynamic model of the pitch and then simulating a pitch
with a guessed set of initial conditions. The results of this simulation
were then compared with an accurately measured trajectory and the residual
vector is computed. This residual vector is then minimized iteratively, by
changing the values of the initial condition vector using a nonlinear
least squares method. The results of this procedure are highly accurate
estimations of the initial conditions of the pitch (see figure below).
Results of this research include the lift, drag and cross-force coefficients
for pitched baseballs. A copy of the dissertation and other baseball papers can be found
on the following link: Dissertation and papers
Primary Researcher - Sean Mish
A machine to throw baseball pitches accurately and repeatably has been developed. This machine will release a ball with specified angular and translational velocities to study the effect of release conditions on the ball's flight. In order to control both the spin of the ball and its translational speed, separate mechanisms have been dedicated to each of these tasks. The parameters under automatic control for each pitch are: release angle (both pitch and yaw), translational velocity, spin axis orientation, and spin rate. This machine is intended for use as a scientific instrument. There are currently no plans for commercial production. Initial development was completed in March 2000, additional refinements in the machine can and will occur with incoming students in the following years.
For more information on the status of this machine please click below.
UC Davis Baseball Pitching Machine
Primary Researchers - LeRoy Alaways, Sean Mish and Mont Hubbard
The Sports Biomechanics Lab sent three researchers to the 1996 Summer Olympic Games to analyze the aerodynamics of the pitch during the games. The team used two 120 Hz cameras supplied by Peak Peformance Technologies, Inc. to track the pitch from release to homeplate. This software developed by LeRoy Alaways for his initial conditions research was then modified to determine the initial conditions of these pitches. A paper is currently in the review process. Abstracts
Major League Baseball
Baseball Hall of Fame
SABR - Society for American Baseball Research
This page was last updated on 04/19/2000.