Wearable Inertial Sensors for Step Width Measurement
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing gait measurement systems face challenges in accurately and affordably measuring step width, often requiring expensive equipment like force plates or complex setups with multiple cameras, and existing ultrasonic wave-based systems struggle to measure step width effectively.
Innovation Solution
A gait information generation device that uses sensor data from acceleration and angular velocity sensors embedded in footwear to calculate step width by determining the increment of lateral distance between the heels of both feet, allowing for simple and accurate generation of gait information.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a floor embedded type force plate is used to measure step width, then measurement accuracy is improved, but device cost and installation complexity increase
Solution Approach 1:
The patent replaces the mechanical force plate system with an inertial measurement system using accelerometers and gyroscopes in wearable sensors. This substitution eliminates the need for complex floor construction while maintaining measurement capability through motion sensing and integration algorithms that calculate step width from acceleration data.
Solution Approach 2:
The wearable sensors measure gait parameters directly on the user's body during natural movement, eliminating the need for specialized measurement environments. The system serves itself by using the user's own motion to generate measurement data without requiring external infrastructure like force plates or controlled camera setups.
2Ease of manufacture
If an inexpensive simple force plate is used, then device cost is reduced, but measurement stability deteriorates due to insufficient distance
Solution Approach 1:
The patent replaces the mechanical force plate with wearable inertial sensors that measure gait parameters during natural movement. This eliminates the distance constraint of simple force plates while maintaining low cost, as the sensors can be placed on the user's body rather than requiring a large measurement area.
3Ease of manufacture
If a camera system is used to measure step width, then device cost is reduced compared to force plates, but measurement complexity increases due to correction requirements
Solution Approach 1:
The patent replaces the optical camera system with inertial measurement sensors worn on the body. This substitution eliminates the need for complex image correction algorithms and calibration processes, as the sensors directly measure acceleration and orientation data that can be integrated to calculate step width without post-processing corrections.
4Ease of operation
If ultrasonic wave-based measurement is used, then non-contact measurement is achieved, but step width measurement capability is lost
Solution Approach 1:
The patent replaces ultrasonic wave-based distance measurement with inertial measurement using accelerometers and gyroscopes. While ultrasonic methods provide non-contact measurement, they cannot capture the lateral motion dynamics needed for step width. The inertial sensors worn on the body directly measure the lateral acceleration and orientation changes that define step width, providing the missing measurement capability.
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 the generation of gait information related to step width with a simple configuration, using sensor data from footwear sensors to calculate the step width, providing a cost-effective and environment-independent solution for gait analysis.
Implementation Method 1
an acceleration sensor that measures accelerations in three axial directions
Implementation Method 2
an angular velocity sensor that measures angular velocities around three axes
Data Source
AI summary
A gait information generation device includes a communication unit that acquires sensor data measured in response to a motion of a foot, an increment calculating unit that calculates an increment of a lateral distance by using lateral acceleration included in the sensor data, a gait information generating unit that calculates, as a step width, a sum of a heel center distance substantially equivalent to a distance between center lines of heels of both feet in an initial state and a sum total of the increments of the lateral distance, and generates gait information related to the calculated step width, and an output unit that outputs the generated gait information.