Foot Angle Calculation Using Angular Velocity Vectors
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Solution Overview
Problem
Existing gait measurement systems face challenges in accurately measuring the foot angle of pedestrians, requiring large devices or image analysis, and struggle with measurement errors when past detection values are not stored.
Innovation Solution
A foot angle calculation device and method using angular velocity vectors to calculate the posture angle and foot angle, which is the angle formed by the velocity vector and the center line of the foot, allowing for accurate measurement with a compact system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a seat type pressure sensor is used to detect walking trace, then the foot angle can be measured, but a large-scale device is required
Solution Approach 1:
The patent replaces the mechanical pressure sensor system with an inertial measurement unit (IMU) that uses acceleration sensors and angular velocity sensors to calculate foot angle through signal processing. This substitution of mechanical detection with inertial sensing and computational methods enables compact device design while maintaining measurement capability
Solution Approach 2:
The patent introduces an angular velocity vector as an intermediary parameter to bridge the relationship between acceleration data and foot angle. By calculating the posture angle from the angular velocity vector and combining it with acceleration data, the system achieves accurate foot angle measurement without requiring direct mechanical pressure detection
2Measurement precision
If image captured by camera is analyzed, then the foot angle can be measured, but the foot angle is not easily measured
Solution Approach 1:
The patent replaces optical image analysis with inertial sensing using acceleration and angular velocity sensors. This substitution eliminates the complexity of image processing and camera-based detection, providing a more direct and computationally efficient method for measuring foot angle through physical sensor data
3Measurement precision
If transition portion of past detection value is extracted, then the measurement error can be corrected, but when the transition portion is not stored, the measurement error cannot be corrected
Solution Approach 1:
The patent makes the system self-sufficient by calculating the posture angle in real-time from the angular velocity vector without requiring storage of historical transition data. The angular velocity sensor provides continuous orientation information that enables ongoing error correction and accurate foot angle calculation without relying on previously stored detection values
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 easy and accurate measurement of the foot angle of pedestrians using a compact system, improving measurement precision and reducing errors by integrating angular velocity data with acceleration data.
Implementation Method 1
an angular velocity sensor that measures an angular velocity of the foot portion
Implementation Method 2
an acceleration sensor that measures an acceleration of the foot portion
Data Source
AI summary
A foot angle calculation device including: a posture angle calculation unit that calculates a posture angle by using an angular velocity vector of a foot portion; and a foot angle calculation unit that calculates a foot angle that is an angle formed by a velocity vector of the foot portion and a center line of a foot by using the velocity vector and the posture angle.