Head-Mounted Accelerometer Ground-Contact Timing Estimation

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Solution Overview

Problem

Conventional running analysis devices cannot estimate ground-contacting timings accurately when attached to the head or neck of a user, as they are designed for waist attachment and lack specific methods for detecting feature points during running exercises performed while wearing the device on the head.

Innovation Solution

A running analysis device incorporating a processor, memory, and a motion sensor with an acceleration sensor attached to the head or neck, which obtains and processes acceleration data to set a candidate time range for ground-contacting timings based on minimum values in Z-axis and Y-axis acceleration data, improving estimation accuracy by considering a time lag.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If an acceleration sensor is attached to the waist to estimate ground-contacting timings, then the estimation can be performed using conventional methods, but the device cannot be attached to the head or neck and cannot estimate ground-contacting timings when the user is running

Engineering Contradiction:

Improveattachment position flexibilityVSAvoidground-contacting timing estimation accuracy

Core Design Contradiction:

Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The patent applies local quality by using different acceleration data and processing methods depending on the attachment position. When attached to the head or neck, the system uses vertical acceleration data (up direction perpendicular to moving direction) to detect ground-contacting timings, whereas waist attachment would use different measurement approaches. This localized adaptation of measurement quality enables accurate ground-contacting timing detection regardless of attachment position.

Inventive Principle:

Principle #3Local quality

2Ease of operation

If the device is attached to the head or neck to reduce user burden and integrate into everyday wearables, then adaptability improves, but the ability to estimate ground-contacting timings accurately is lost

Engineering Contradiction:

Improveuser burden reductionVSAvoidground-contacting timing estimation accuracy

Core Design Contradiction:

Ease of operationVSMeasurement precision

Solution Approach 1:

The patent changes the measurement parameters based on attachment position. For head or neck attachment, it uses vertical acceleration data (up direction perpendicular to moving direction) and processes it through specific algorithms including setting candidate time ranges and detecting minimum values in the acceleration data. This parameter adaptation enables accurate ground-contacting timing estimation while maintaining the ease of head/neck attachment.

Inventive Principle:

Principle #35Parameter changes

3Device complexity

If conventional waist-attached device methods are used for head-attached devices, then device complexity remains low, but measurement precision for ground-contacting timings deteriorates

Engineering Contradiction:

Improveprocessing method simplicityVSAvoidground-contacting timing estimation accuracy

Core Design Contradiction:

Device complexityVSMeasurement precision

Solution Approach 1:

The patent segments the acceleration data processing into distinct stages: obtaining vertical acceleration data, setting candidate time ranges based on acceleration thresholds, and detecting minimum values within those ranges. This segmented approach systematically processes the data to improve ground-contacting timing accuracy while maintaining manageable device complexity through structured processing steps.

Inventive Principle:

Principle #1Segmentation

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 ground-contacting timings during running by utilizing acceleration sensors attached to the head or neck, enhancing accuracy and reducing user burden with a device that can be integrated into everyday wearables like headphones or sunglasses.

Implementation Method 1

first acceleration data on an acceleration in an up direction perpendicular to a moving direction of a subject and second acceleration data on an acceleration in a direction opposite to the moving direction of the subject are obtained from a motion sensor attached to a head or a neck of the subject and including an acceleration sensor

Methodology Applied

Scientific EffectAcceleration: Accelerometer

Data Source

PatentUS11653858B2Running analysis device

Publication Date: 2023.05.23 CASIO COMPUTER CO LTD

AI summary

A running analysis device includes a processor and a memory storing a program. By executing the program, the processor performs obtainment, setting, and estimation processes. By the obtainment process, first data on an acceleration in an up direction perpendicular to a moving direction of a subject and second data on an acceleration in a direction opposite to the moving direction are obtained from a motion sensor attached to the subject's head or neck and including an acceleration sensor, the first and second data being detected by the acceleration sensor while the subject is running. By the setting process, a candidate time range including a candidate timing for a ground-contacting timing when a foot of the subject contacts the ground is set based on the first data. By the estimation process, the ground-contacting timing is estimated in the candidate time range, based on a timing when the second data is minimum.