Generalized Coordinate Acceleration Conversion for IMU Motion Capture
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Solution Overview
Problem
IMU motion capture techniques face challenges in accurately estimating high-frequency components of acceleration, leading to incomplete reflection of high-accuracy data in processing, especially during double-leg support phases where external force distribution is complex.
Innovation Solution
An information processing device and method that acquire position and acceleration data from inertial sensors, apply transformation rules to convert data into a generalized coordinate system, and estimate joint torque and ground reaction forces using forward and inverse dynamics calculations, enhancing the followability of high-frequency operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If acceleration data is obtained by second-order differentiating position data in IMU motion capture, then processing is simplified, but high-frequency components are lost due to smoothing
Solution Approach 1:
The patent introduces an intermediary transformation process that converts acceleration data from sensor coordinate systems to a generalized coordinate system using transformation matrices derived from position data. This mediator approach allows the system to utilize raw high-frequency acceleration data without direct second-order differentiation, thereby preserving measurement precision while maintaining processing feasibility through coordinate transformation rather than numerical differentiation.
2Measurement precision
If external force is distributed to multiple contact points in double-leg support phase, then measurement accuracy improves, but calculation complexity increases due to countless distribution methods
Solution Approach 1:
The patent transforms the complex force distribution problem into a parameter optimization problem by expressing external forces at multiple contact points as functions of generalized coordinates and applying transformation matrices. This parameter change approach converts the ill-posed distribution problem into a determinate calculation based on coordinate transformations and measured acceleration data, reducing complexity while maintaining accuracy.
Solution Approach 2:
The patent replaces the mechanical approach of directly measuring or distributing forces with a computational substitution using coordinate transformations and acceleration data. Instead of physically resolving force distribution through mechanical means or complex statics calculations, the system substitutes this with mathematical transformations of acceleration data from the generalized coordinate system, simplifying the calculation while preserving accuracy.
Data Source
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AI summary
Provided is an information processing device including: a storage device having a program stored therein; and a hardware processor, wherein the hardware processor executes the program stored in the storage device to: acquire first data for a dimension of position relating to an object represented in a generalized coordinate system; acquire at least second data for a dimension of acceleration from a plurality of inertial sensors attached to the object; and convert the second data into third data for a dimension of acceleration represented in the generalized coordinate system on the basis of the first data.