Pulse Wave Sensor Biaxial Rotation and Dynamic Pressure Control
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Solution Overview
Problem
Existing vital information measuring devices face accuracy issues due to inconsistent pressing force and lack of flexible control over the sensor's pressing state against the body surface, leading to potential errors in pulse wave detection.
Innovation Solution
A pulse wave detecting device with a biaxial rotation mechanism and an air bag system that allows for flexible control of the sensor's pitch and roll angles, along with adjustable pressing force, to ensure optimal contact with the body surface, improving detection accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the pressing force is increased to ensure consistent contact between the sensor and body surface, then detection reliability is improved, but measurement precision deteriorates due to errors in tonometry state and determination accuracy
Solution Approach 1:
The pressing force is changed dynamically based on the measurement phase. During rotation angle control, a first pressing force is applied, and during pulse wave detection, a second pressing force (different from the first) is applied. This dynamic adjustment allows the system to optimize for either alignment accuracy or detection reliability depending on the current operational phase, resolving the contradiction between maintaining consistent contact and avoiding measurement errors.
2Ease of operation
If the sensor rotation is performed mechanically to release pressure from the wrist, then ease of operation is improved, but adaptability deteriorates due to inability to electrically control the pressing state
Solution Approach 1:
The mechanical rotation mechanism for pressure release is replaced with electrical control of the pressing force. The control unit electrically adjusts the pressing force applied by the air bag to rotate the sensor about the artery, providing both ease of operation through automated control and adaptability through programmable pressing force adjustment based on measurement phase and artery conditions.
Data Source
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AI summary
The present invention provides a pulse wave detecting device capable of improving pulse wave detection accuracy by flexibly changing a pressing state, toward a body surface, of a sensor section pressed against the body surface for use, a vital information measuring device, a method for controlling a pulse wave detecting device, and a control program for a pulse wave detecting device. A sensor section 6 is rotatable about a first axis X and is rotatable about a second axis Y. A control unit 12 determines a rotation angle about the second axis Y (an optimal roll angle) and a rotation angle about the first axis X (an optimal pitch angle) in a state where the sensor section 6 is pressed against the body surface with a prescribed pressing force. After determining the optimal roll angle and the optimal pitch angle, the control unit reduces the pressing force to a reset value smaller than the prescribed pressing force and larger than zero, increases the pressing force from this state, detects a pulse wave based on pressure signals detected by pressure detecting elements 6a and 7a during the increase, and calculates vital information based on the detected pulse wave.