Motion Tracker Positioning via Wireless Angle Computation

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Solution Overview

Problem

Motion tracking systems face inaccuracies due to incorrect positioning of trackers on the body, which can lead to improper supervision of rehabilitation exercises, potentially causing injuries during physical rehabilitation procedures.

Innovation Solution

A method using inertial sensors and multiple antennas on both trackers and a computing device to determine the precise positioning of trackers on body members by computing angles of arrival and departure of data packets, ensuring accurate correspondence between trackers and body members through wireless communication.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If calibration is performed manually by having the person perform certain movements, then the system can infer tracker positions, but user mistakes during calibration can lead to incorrect tracker-body member correspondence

Engineering Contradiction:

Improvetracker position identification accuracyVSAvoidcalibration process reliability

Core Design Contradiction:

Measurement precisionVSReliability

Solution Approach 1:

The patent replaces the manual mechanical calibration process with an automated electromagnetic field-based system. Instead of relying on users to perform physical movements for calibration, the system uses wireless signal transmission and angle of arrival computations to automatically determine tracker positions on body members, eliminating user error in the calibration process

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The system performs self-calibration by automatically computing tracker positions based on wireless communications between the computing device and trackers. The computing device autonomously determines the correspondence between trackers and body members without requiring user intervention or manual calibration movements

Inventive Principle:

Principle #25Self-service

2Measurement precision

If multiple antennas are used on trackers and computing device to compute angles of arrival, then tracker positioning accuracy is improved, but device complexity increases

Engineering Contradiction:

Improvetracker position determination accuracyVSAvoidnumber of antennas and computational complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The multiple antennas in the system serve multiple functions: they enable angle of arrival computations for position determination, provide wireless communication capabilities for data transmission, and support signal processing for tracker identification. This multi-functionality justifies the added complexity by consolidating several capabilities into a single antenna array system

Inventive Principle:

Principle #6Universality (Multi-functionality)

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

This approach enhances the accuracy of motion tracking sequences by correctly identifying tracker positions, reducing the risk of injury during rehabilitation exercises and improving the reliability of the tracking system.

Implementation Method 1

wirelessly receiving, by each tracker of the plurality of trackers from the computing device, one or more first data packets through each antenna of the plurality of antennas of the respective tracker

Methodology Applied

Scientific EffectElectromagnetic radiation: Electromagnetic Induction

Implementation Method 2

digitally determining, by each tracker of the plurality of trackers, a first direction in which the computing device is relative to the respective tracker by computing an angle of arrival of the one or more first data packets

Methodology Applied

Scientific EffectAngle of arrival computation:

Data Source

PatentUS12105177B2Assessment of position of motion trackers on a subject based on wireless communications

Publication Date: 2024.10.01 SWORD HEALTH SA

AI summary

Motion tracking systems and methods for determining how a plurality of trackers is positioned on a plurality of body members of a person may include: wirelessly receiving, by a computing device, one or more first data packets of each tracker of the plurality of trackers; digitally determining a first direction in which the computing device is relative to the respective tracker by computing an angle of departure of the one or more first data packets; digitally determining based on the first directions, a second direction in which each tracker of the plurality of trackers is relative to one or more other trackers of the plurality of trackers; and digitally determining on which body member is each tracker of the plurality of trackers positioned on the person at least based on both the second directions and the plurality of body members requiring to have a tracker positioned thereon.