Sensor Calibration for Bed Elevation Angles
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Solution Overview
Problem
Existing sensor calibration methods struggle to accurately calibrate sensors attached to subjects in supine positions with or without bed tilting, leading to inaccurate posture detection and physiological assessments.
Innovation Solution
A method and system that determine a sensor elevation angle by accounting for body contour and bed tilting, using algorithms such as the Calibration in Supine Algorithm, Sensor Elevation Angle Algorithm, and Calibration with Sensor Angle Algorithm to align the sensor frame with the body frame and gravity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If sensor calibration is performed at standardized supine position with no body elevation, then calibration accuracy is improved, but practical applicability deteriorates due to bed tilting requirements
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting the calibration algorithm to account for bed elevation angle as a variable parameter. Instead of assuming a fixed horizontal bed position, the system incorporates the actual bed tilt angle into the calibration calculations, allowing accurate calibration across different bed positions (0°, 30°, 45°, 60°) while maintaining measurement precision.
Solution Approach 2:
The patent implements dynamics by making the calibration process adaptive to changing bed positions. The system automatically detects or receives bed elevation angle information and adjusts the calibration procedure accordingly, transitioning from a static standardized calibration to a dynamic calibration that adapts to various practical bed configurations.
2Stability of the object's composition
If sensor attachment location and orientation are standardized, then calibration consistency is improved, but ease of operation deteriorates due to strict positioning requirements
Solution Approach 1:
The patent applies local quality by allowing the sensor to be attached at different locations on the subject's body (such as chest, abdomen, or limb) while maintaining calibration consistency through location-specific calibration algorithms. Each attachment location has its own calibration parameters that account for the local anatomical geometry and sensor orientation relative to the body.
Solution Approach 2:
The patent implements universality by creating a multi-functional calibration system that can handle various sensor attachment locations, bed elevation angles, and subject positions using a single integrated approach. The system provides universal calibration capabilities across different scenarios rather than requiring separate standardized procedures for each configuration.
3Adaptability or versatility
If bed elevation is maintained at non-standard angles (30°, 45°, 60°), then patient comfort and treatment requirements are improved, but posture detection accuracy deteriorates
Solution Approach 1:
The patent applies feedback by continuously monitoring or receiving bed elevation angle information and using this feedback to adjust the posture detection algorithm. The system incorporates real-time bed angle data into the acceleration vector calculations, ensuring that posture detection remains accurate even when the bed is tilted at therapeutic angles.
Solution Approach 2:
The patent implements parameter changes by modifying the acceleration vector transformation equations to include bed elevation angle as a variable parameter. This allows the system to accurately calculate vertical body angles and detect postures while the bed is positioned at various elevation angles, maintaining measurement precision across different patient positioning scenarios.
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 tracking of relative body positions and posture detection, reducing errors in vertical body angle calculations and improving the accuracy of physiological and physical assessments, even at elevated bed angles.
Implementation Method 1
alignment of the sensor device frame to the subject's body frame with reference to gravity
Implementation Method 2
a sensor (e.g., an accelerometer) attached to a subject
Data Source
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AI summary
A system, device and method of calibrating a sensor determine a sensor vector associated with a subject; process the sensor vector; determine a sensor elevation angle as a prediction of the subject's body elevation from a result of processing the sensor vector; and perform calibration using the sensor vector, sensor elevation angle, and a gravity vector.