Foot-Mounted Ultrasonic Measurement for Daily-Walking Step Width

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Solution Overview

Problem

Existing technologies cannot accurately measure step width during daily walking, despite being able to measure the distance between feet during walking or running.

Innovation Solution

A step width measurement device that calculates step width by using propagation data from ultrasonic waves transmitted and received by devices on both feet, combined with sensor data including spatial acceleration and angular velocity to determine the height of the sensor, allowing for precise step width calculation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If ultrasonic wave transmission/reception devices are mounted on both feet to measure distance between feet, then the distance between both feet can be measured during walking or running, but the step width cannot be measured

Engineering Contradiction:

Improvedistance between feet measurementVSAvoidstep width measurement capability

Core Design Contradiction:

Measurement precisionVSAdaptability or versatility

Solution Approach 1:

The patent introduces a new dimension of measurement by calculating the vertical height of the sensor from the ground using sensor data (spatial acceleration and spatial angular velocity). This height information is then combined with the horizontal distance between feet to compute the step width, effectively adding a vertical dimension to the measurement system to enable step width calculation.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The patent uses sensor data (spatial acceleration and spatial angular velocity) as an intermediary to indirectly determine the sensor height. Instead of directly measuring height, the system uses the sensor's movement characteristics during walking to calculate the height, which then serves as a mediator to compute the step width from the distance between feet.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Device complexity

If only distance between feet is measured using ultrasonic waves, then the measurement system remains simple, but accurate step width measurement during daily walking cannot be achieved

Engineering Contradiction:

Improvemeasurement system structureVSAvoidstep width measurement accuracy

Core Design Contradiction:

Device complexityVSMeasurement precision

Solution Approach 1:

The patent merges multiple measurement components into a unified system: ultrasonic wave transmission/reception devices for distance measurement, sensors (measuring spatial acceleration and spatial angular velocity) for height calculation, and a calculation unit that integrates both datasets. This combination enables accurate step width measurement while maintaining practical system complexity.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The measurement system is designed with multi-functionality to achieve step width measurement. The same ultrasonic devices and sensors used for distance and height measurement are integrated into a single system that performs multiple functions: measuring distance between feet, calculating sensor height, and computing step width, thereby avoiding the need for separate dedicated devices.

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

Enables accurate measurement of step width during daily walking, providing a basis for personalized healthcare services based on gait parameters.

Implementation Method 1

an ultrasonic wave emitted from an ultrasonic transmitting unit provided on one foot is received by a wave receiving unit provided on the other foot, and a distance between both feet is calculated based on a propagation time of the ultrasonic wave

Methodology Applied

Scientific EffectUltrasonic wave propagation: Ultrasound

Implementation Method 2

a distance between both feet is calculated based on a propagation time of the ultrasonic wave

Methodology Applied

Scientific EffectTime of flight measurement: Time of Flight

Implementation Method 3

sensor data including a spatial acceleration and a spatial angular velocity measured by sensors mounted on each of the both feet of the user

Methodology Applied

Scientific EffectAcceleration measurement: Accelerometer

Data Source

PatentUS12458247B2Step width measurement device, measurement system, step width measurement method, and program for decision making related to user's walking

Publication Date: 2025.11.04 NEC CORP

AI summary

A step width measurement device includes a distance calculation unit that calculates a distance between both feet of a user by using propagation data related to transmission/reception times of ultrasonic waves transmitted/received by ultrasonic transmission/reception devices mounted on each of the both feet of the user, a height calculation unit that calculates a height of a sensor by using sensor data including a spatial acceleration and a spatial angular velocity measured by sensors mounted on each of the both feet of the user, and a step width calculation unit that calculates a step width of the user by using the distance between the both feet measured at the same timing and the height of the sensor.