Wearable Cuff Pressure Control for Low-Noise Blood Pressure Sensing
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Solution Overview
Problem
Existing wearable devices for non-invasive blood pressure monitoring face challenges such as noise and pressure variations due to piezoelectric transducer pumps, which affect accurate photoacoustic and pulse wave velocity measurements, and are sensitive to temperature and altitude changes.
Innovation Solution
Implementing discrete pressure levels with a feedback loop using fuzzy logic, PID controller, and predictive models to maintain target pressure, reducing noise and variations, and ensuring accurate biometric measurements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of moving object
If piezoelectric transducer pumps are used to apply pressure, then continuous pressure control is achieved, but noise and pressure variations increase affecting measurement accuracy
Solution Approach 1:
The system applies pressure in discrete steps rather than continuous variation, holding each pressure level for a predetermined time period. This periodic, stepped approach eliminates the noise and pressure variations associated with continuous pump operation while maintaining adequate pressure control for measurements.
Solution Approach 2:
The system uses feedback loops with fuzzy logic and PID controllers to maintain target pressure levels at each discrete step. This feedback mechanism ensures stable pressure control during measurement periods without requiring continuous pump operation, thereby reducing noise.
2Measurement precision
If discrete pressure levels are implemented, then noise and pressure variations are reduced, but device complexity increases due to feedback loops and control mechanisms
Solution Approach 1:
The system employs self-regulating control mechanisms where the feedback loops automatically adjust pressure levels without external intervention. The fuzzy logic and PID controllers autonomously maintain target pressure levels, reducing the need for complex manual control systems.
3Measurement precision
If pressure is applied continuously for blood pressure monitoring, then accurate measurements are obtained, but user discomfort increases
Solution Approach 1:
The system applies pressure in discrete steps with predetermined holding periods rather than continuous pressure application. This periodic approach allows measurements to be completed at each pressure level before moving to the next, reducing overall pressure exposure time and user discomfort while maintaining measurement accuracy.
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
Achieves clean, accurate, and continuous blood pressure monitoring with minimal user discomfort, suitable for both clinical and consumer applications, including overnight sleep monitoring.
Implementation Method 1
photoacoustic sensors
Implementation Method 2
piezoelectric transducer pumps
Data Source
AI summary
Devices and systems for controlling pressure during sensing are disclosed. Such sensors and/or systems may be embodied in a wearable user device. The wearable user device may include a cuff configured to apply a pressure to a portion of a user at a plurality of discrete pressure levels over a plurality of time periods; a biometric sensor configured to obtain a plurality of sensor measurements associated with a blood vessel of the user at corresponding ones of the plurality of discrete pressure levels during corresponding ones of the plurality of time periods; and a wearable structure including the cuff and the biometric sensor.