Walking Measurement Device Lateral Acceleration Foot Differentiation
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Solution Overview
Problem
Conventional pedometers cannot accurately determine whether each step is made by the right foot or the left foot due to incorrect differentiation between foot landing and unrelated arm movements, leading to compromised accuracy in step counting.
Innovation Solution
A walking measurement device using an acceleration sensor to detect lateral acceleration and integrate values over specific periods, comparing these values to determine the foot landing timing and accurately differentiate between right and left foot impacts, with additional features like threshold comparison and angular velocity sensing to enhance accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If only acceleration detection is used to count steps, then the device complexity is reduced, but the measurement precision deteriorates due to inability to differentiate foot landing from arm movements
Solution Approach 1:
The patent segments the acceleration signal analysis into distinct time periods: impact generation timing detection, intermediate period identification, and swing period analysis. By dividing the walking cycle into these segments and analyzing acceleration characteristics in each segment, the system can differentiate foot landing impacts from arm movement accelerations, thereby improving measurement precision without adding complex hardware
Solution Approach 2:
The patent applies preliminary action by detecting impact generation timing first, then using this timing information to define subsequent intermediate periods for integration analysis. This preliminary detection of impact events allows the system to selectively analyze only the relevant time windows, improving accuracy while maintaining simple device configuration
2Measurement precision
If integration period is extended to capture more walking cycle data, then the measurement precision improves, but the loss of time increases due to longer processing intervals
Solution Approach 1:
The patent implements periodic action by analyzing acceleration integration values at regular intervals defined by consecutive impact generation timings. Instead of continuous processing, the system periodically evaluates the intermediate period between impacts, which maintains measurement precision while reducing overall processing time through this rhythmic, interval-based analysis approach
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
The device accurately determines each step as either a right or left foot landing, improving the accuracy of step counting and reducing errors from unrelated movements, while simplifying the device configuration by using a single acceleration sensor.
Implementation Method 1
an acceleration sensor that detects acceleration in a lateral direction along which a left foot and a right foot are arranged side by side
Implementation Method 2
a timing detection unit that detects impact generation timing based on the detected acceleration
Data Source
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AI summary
In a normal walking motion, a rightward acceleration Ax becomes dominant in a left foot landing period, and a leftward acceleration Ax becomes dominant in a right foot landing period. Thus, an integrated value S of the acceleration Ax over an intermediate period between two consecutive impact generation timings changes in a regular pattern of alternately increasing and decreasing with respect to each step. Accordingly, by comparing the integrated values S acquired with respect to two consecutive intermediate periods temporally separated by one impact generation timing, it is possible to determine whether the one impact generation timing corresponds to the landing timing of the left foot or the landing timing of the right foot.