Foot Pronation Estimation Using Coronal Plane Angular Waveforms
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Solution Overview
Problem
Existing foot abnormality analysis devices require a complex configuration with multiple sensors to determine the degree of pronation/supination, making them cumbersome and difficult to implement effectively.
Innovation Solution
An estimation device that detects the terminal stance period from time-series sensor data and extracts feature amounts from angular waveforms in the coronal plane to estimate the degree of pronation/supination using a simpler configuration, including a detection unit, feature amount extraction unit, and presumption unit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple pressure sensors are used to determine centroid point, centroid line, arch, and bone axis of the foot, then measurement precision of foot abnormality is improved, but device complexity increases
Solution Approach 1:
The patent extracts only the essential feature needed for pronation/supination estimation - the angular waveform in the coronal plane during terminal stance period - from the complete set of foot parameters. By focusing solely on this specific angular characteristic rather than computing all foot parameters (centroid point, centroid line, arch, bone axis), the system achieves accurate estimation with minimal sensors.
Solution Approach 2:
The patent segments the gait cycle into specific phases (terminal stance period) and extracts features only from this relevant segment. By analyzing angular waveforms specifically during the terminal stance period rather than the entire gait cycle, the system reduces the data processing burden and sensor requirements while maintaining estimation accuracy.
2Device complexity
If a simple configuration with fewer sensors is used, then device complexity is reduced, but measurement precision may deteriorate
Solution Approach 1:
The patent introduces an intermediary processing step that transforms simple sensor measurements into meaningful clinical indicators. By calculating the angular waveform in the coronal plane from basic sensor data and analyzing its characteristics during the terminal stance period, the system bridges the gap between simple sensor configurations and accurate pronation/supination estimation.
Solution Approach 2:
The patent changes the parameter being measured from multiple static foot parameters (centroid point, centroid line, arch, bone axis requiring multiple pressure sensors) to a dynamic angular waveform parameter that can be derived from inertial measurements. This parameter transformation enables accurate estimation with fewer sensors.
Data Source
AI summary
An estimation device that includes a detection unit that detects a terminal stance period from time-series data of sensor data based on a physical quantity related to movement of a foot measured by a sensor provided at a foot portion, a feature amount extraction unit that extracts a feature amount from an angular waveform in a coronal plane during the terminal stance period, and a presumption unit that estimates a degree of pronation/supination of the foot by using the feature amount extracted from the angular waveform in the coronal plane.