Impact Position Estimation for Baseball Batting with a Force-Irrelevant Vibration Feature.

Area of Science:

• Sports Science
• Mechanical Engineering
• Biomechanics

Background:

• Accurate baseball impact position estimation is crucial for performance analysis.
• Existing methods may be confounded by variations in impact force.
• Novel force-independent techniques are needed for reliable measurement.

Purpose of the Study:

• To develop and validate a novel method for estimating baseball impact position.
• To identify vibration signal features that are independent of impact intensity (force-irrelevant).
• To assess the efficacy of these features in both static and dynamic batting experiments.

Main Methods:

• A piezoelectric vibration sensor was attached to a wooden bat's knob.
• Vibration signals were recorded from controlled impacts at 40 positions and 3 intensities (static experiment).
• Vibration signals were also collected during actual batting by three players (dynamic experiment).

Main Results:

• Peak signal amplitude and eigenfrequency peaks correlated with impact intensity.
• Ratios of the first three eigenfrequency peaks remained consistent across intensities.
• This force-irrelevant feature was observed in both static and dynamic experiments.

Conclusions:

• The ratios of peaks at the first three eigenfrequencies are a reliable, force-irrelevant feature for impact position estimation.
• This method offers a robust approach to analyzing baseball impacts.
• The findings have implications for sports technology and performance analytics.