Table Tennis Stroke Planning Using Ball Spin Trajectory Prediction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing table tennis robots struggle to predict and return a ball with spin to a target position with precision due to the lack of consideration for rotational velocity in their decision-making processes.
Innovation Solution
A stroke decision device that acquires state information including position, velocity, and rotational velocity of the incoming ball, and computes a stroke condition for the striking implement to adjust the ball's trajectory, ensuring accurate return to a target arrival position by predicting and adjusting post-strike velocities and orientations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If simple aerodynamic modeling without rotational velocity is used, then processing load is reduced, but prediction precision of ball trajectory is worsened when ball is applied with spin
Solution Approach 1:
The patent changes the parameters used in aerodynamic modeling from simple velocity-based parameters to include rotational velocity parameters. Specifically, it incorporates the ball's rotational velocity (spin) into the aerodynamic force calculations, allowing the model to account for Magnus effect and other spin-related phenomena while maintaining computational efficiency through parameterized formulations.
Solution Approach 2:
The patent performs preliminary calculation of aerodynamic parameters and pre-computes certain trajectory characteristics based on the ball's state information including rotation. By pre-calculating the effects of spin on trajectory before the actual stroke decision, the system reduces real-time computational load while maintaining high prediction accuracy.
2Device complexity
If rotational velocity is not considered in stroke decision, then device complexity is reduced, but return precision to target position is worsened when ball has spin
Solution Approach 1:
The stroke decision device incorporates rotational velocity as an additional parameter in its decision-making process. The system calculates the required stroke conditions (racket velocity, angle, and spin) by considering the incoming ball's rotational velocity and adjusting the return stroke parameters accordingly, enabling precise control of the returned ball's trajectory despite the increased computational complexity.
Solution Approach 2:
The system uses feedback from the detected ball state information (including rotation) to adjust the stroke conditions. By continuously monitoring the ball's rotational velocity and using this information to modify the return stroke parameters, the system achieves high precision in returning the ball to the target position while maintaining a relatively simple control architecture.
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 precise return of the ball to a target position even when applied with spin, by considering rotational velocity and adjusting post-strike conditions to minimize error.
Implementation Method 1
employ simple aerodynamic modeling that does not require input of a rotational velocity
Implementation Method 2
it is difficult for the table tennis robot to predict a pre-strike and post-strike trajectory of the ball when returning the ball with good precision if the ball is applied with spin
Data Source
AI summary
A stroke decision device 30 includes an acquisition section 31 configured to acquire state information including a position, a velocity, and a rotational velocity of an incoming ball, and a stroke decision section 32 configured to decide a stroke condition including a position, a velocity, and an orientation of a striking implement at a time point when hitting back the ball toward a target arrival position, based on the state information for the ball and the target arrival position when hitting back the ball with the striking implement.