Swing Analysis System Using Inertial Sensor Data Transformation
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Solution Overview
Problem
Existing methods for analyzing swings in sports, such as golf, tennis, and baseball, struggle to transform sensor data from a sensor-based reference frame to a meaningful reference frame that is insensitive to changes in orientation, and they fail to combine analysis of the sweet spot trajectory with a swing plane reference frame.
Innovation Solution
A system that analyzes a swing by transforming sensor data to a swing plane reference frame, which reflects the physics and geometry of the swing, allowing for detailed characterization and comparison of swing metrics across different swings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If sensor data is analyzed in a sensor-based reference frame, then the measurement process is simple, but the results are sensitive to changes in orientation and lack physical meaning
Solution Approach 1:
The patent introduces a swing plane reference frame as an intermediary coordinate system that mediates between the sensor's local reference frame and the meaningful physical reference frame. This intermediary frame is defined by the swing geometry (sweet spot trajectory plane) and allows transformation of sensor measurements into physically meaningful metrics that are insensitive to sensor orientation changes.
Solution Approach 2:
The patent transforms the reference frame parameters from a fixed sensor-based coordinate system to a dynamic swing-plane-based coordinate system. By changing the reference frame parameters to align with the swing geometry (using the sweet spot trajectory to define the swing plane), the measurements become physically meaningful and invariant to sensor orientation.
2Stability of the object's composition
If vector magnitudes are used to define swing metrics, then the metrics are invariant to rotations, but detailed and physically meaningful information is lost
Solution Approach 1:
The patent moves from using only vector magnitudes (scalar quantities) to using vector components in a specifically oriented reference frame. By projecting measurements onto axes defined by the swing geometry (tangent to sweet spot trajectory, normal to swing plane), the system retrieves directional information that was lost when using only magnitudes, while maintaining invariance through the geometric definition of the reference frame.
3Productivity
If existing swing analysis methods are used, then the analysis can be performed, but the methods cannot transform sensor data to a meaningful reference frame insensitive to orientation changes
Solution Approach 1:
The patent performs preliminary action by first determining the swing plane geometry (using sweet spot trajectory to define the reference frame) before analyzing the sensor measurements. This preliminary establishment of the correct reference frame enables subsequent measurements to be automatically transformed into the meaningful coordinate system, making the entire analysis process more accurate.
Data Source
AI summary
An equipment fitting system that measures swings by a user of different pieces of equipment with inertial sensors, and analyzes sensor data to recommend which piece of equipment is optimal for the user from among those tested. Illustrative applications include fitting of baseball bats and golf clubs. Swing metrics calculated from sensor data may include an acceleration metric, a speed metric, and a momentum metric; these metrics may be combined into a metrics score for each piece of equipment. Other factors may be included in an overall score, such as the user's subjective score for each piece of equipment, and ratings from experts or other consumers. Users may assign the relative importance for the different factors to calculate an overall equipment score.