Ball Rotation Estimation via Aerodynamic Trajectory Matching
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Solution Overview
Problem
Existing methods for estimating the rotational velocity of a ball in table tennis systems, such as those described in Non-Patent Documents 1 and 2, face challenges in predicting the ball's trajectory with precision using a simple configuration, particularly when employing a high-speed camera and specialized balls.
Innovation Solution
A rotation estimation device and method that acquires state information including measured position and velocity of the ball, solves an aerodynamic model to predict the ball's position and velocity at a later time point for various provisional rotational velocities, and computes the estimated rotational velocity by minimizing the difference between predicted and measured positions, allowing for precise trajectory prediction without requiring a specialized ball.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a high-speed camera and specialized ball are used to measure rotational velocity, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent replaces the mechanical/optical measurement system (high-speed camera tracking a marked ball) with an aerodynamic modeling system. The rotational velocity is estimated by solving aerodynamic equations that model the ball's flight trajectory, substituting direct optical measurement with computational physics-based estimation.
Solution Approach 2:
The patent introduces aerodynamic modeling as an intermediary between the observed ball trajectory and the desired rotational velocity parameter. Instead of directly measuring rotation, the system uses the ball's flight path as intermediate data to infer rotational velocity through aerodynamic calculations.
2Measurement precision
If a high-speed camera is used to directly measure rotational velocity, then measurement precision is improved, but the configuration becomes complex
Solution Approach 1:
The patent replaces the mechanical/optical measurement system (high-speed camera tracking a marked ball) with an aerodynamic modeling system. The rotational velocity is estimated by solving aerodynamic equations that model the ball's flight trajectory, substituting direct optical measurement with computational physics-based estimation.
3Measurement precision
If direct measurement methods are used, then rotational velocity accuracy is improved, but trajectory prediction precision worsens
Solution Approach 1:
The patent implements a feedback mechanism where the aerodynamic model's trajectory predictions are continuously compared with actual measured ball positions. The rotational velocity estimate is adjusted iteratively to minimize the difference between predicted and observed trajectories, ensuring both accurate rotation estimation and reliable trajectory prediction.
Solution Approach 2:
The patent introduces aerodynamic modeling as an intermediary between the observed ball trajectory and the desired rotational velocity parameter. Instead of directly measuring rotation, the system uses the ball's flight path as intermediate data to infer rotational velocity through aerodynamic calculations.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables accurate estimation of the ball's rotational velocity and precise prediction of its trajectory using a simple configuration, improving prediction accuracy and eliminating the need for specialized balls.
Implementation Method 1
aerodynamic modeling is performed
Data Source
AI summary
The present disclosure provides a rotation estimation device including an acquisition section and a rotation estimation section.