Dynamic Pressure Sensor with Calibration Curves
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Solution Overview
Problem
Current pressure sensors in medical fields, such as those used for plantar pressure monitoring, fail to accurately measure dynamic pressure variations during movements like gait, leading to poor estimates of force measurements due to their static calibration methods.
Innovation Solution
A pressure sensor system comprising capacitive sensors with dynamic calibration curves, a memory for storing these curves, and a computing unit that processes data to compute pressure-related information, allowing for precise measurement of pressure changes over time, including during gait simulations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If static calibration methods are used for pressure sensors, then the sensor structure remains simple and manufacturing is easier, but measurement precision deteriorates during dynamic movements
Solution Approach 1:
The patent applies preliminary action by pre-calibrating pressure sensors under dynamic conditions that simulate actual usage scenarios (gait movements) before deployment. Multiple calibration curves are pre-computed for different rates of pressure variation and stored in memory, so the system can immediately select the appropriate calibration curve without real-time computation, thus improving measurement precision while maintaining relatively simple device architecture.
Solution Approach 2:
The patent implements parameter changes by transitioning from a single static calibration parameter to multiple dynamic calibration parameters. Specifically, it uses multiple calibration curves corresponding to different rates of pressure variation (dP/dt), allowing the system to adapt the calibration parameters based on the actual dynamic conditions during measurement, thereby significantly improving pressure measurement precision during movements.
2Measurement precision
If static calibration curves are used, then data processing is simpler and faster, but the accuracy of force measurement during movements deteriorates
Solution Approach 1:
The patent applies preliminary action by pre-computing multiple calibration curves under various dynamic conditions and storing them in memory before actual use. During measurement, the system only needs to select the appropriate pre-computed curve based on the current rate of pressure variation and apply it to the raw sensor data, rather than performing complex real-time calculations, thus maintaining high data processing efficiency while achieving accurate force measurements.
Solution Approach 2:
The patent implements parameter changes by using different calibration curves for different rates of pressure variation. The system dynamically selects the appropriate calibration parameters based on the measured dP/dt, allowing accurate force measurement across varying dynamic conditions while keeping the processing operation itself simple (curve selection and application).
3Speed
If the sensor responds to rapid pressure variations, then dynamic movement characterization improves, but the sensor's response accuracy deteriorates due to rate-dependent effects
Solution Approach 1:
The patent implements parameter changes by establishing the relationship between measurement accuracy and the rate of pressure variation. It determines optimal calibration parameters for different dP/dt ranges and selects the appropriate parameters based on the current measurement conditions. This allows the sensor to maintain high measurement precision across a wide range of dynamic response speeds.
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 characterization of pressure and force measurements during dynamic movements by accounting for the rate of pressure variation, improving the estimation of force measurements and providing a more precise analysis of gait and other dynamic activities.
Implementation Method 1
The measurement portion comprises a plurality of capacitive pressure sensors
Data Source
AI summary
A pressure sensor including capacitive pressure sensors and computing elements taking into account the dynamic calibration curves of capacitive pressure sensors. Also, an insole including the pressure sensor, which is for insertion into an article of footwear, and a calibration system that includes that includes the insole. Further, a computer-implemented method for determining the notal normal force applied on the pressure sensor.