Bed-Leaving Sensor Using Center of Gravity Tracking
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Solution Overview
Problem
Existing bed-leaving sensors detect bed-leaving after the user has completely left the bed, leading to delayed alerts and increased risk of accidents due to false alarms and early detection timing.
Innovation Solution
A bed-leaving sensor system that includes a sitting position detection member using pressure sensors to identify the user's sitting position and bed-leaving behavior based on conditions such as the sitting position within a preset bed-leaving expectation region, movement volume of the sitting position center of gravity exceeding a threshold, and movement towards a bed-leaving range, allowing for precise detection before the user completely leaves the bed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a pressure sensor is used to detect body pressure at a designated value or less, then bed-leaving detection is achieved, but detection timing is delayed until the user has completely left the bed
Solution Approach 1:
The system performs preliminary detection by monitoring the user's sitting position and center of gravity movement before the user completely leaves the bed. The sitting position detection member identifies when the user is in a sitting posture, and the bed-leaving behavior detection member predicts imminent bed-leaving by tracking center of gravity movement, triggering an alert before the user actually exits the bed.
2Loss of time
If bed-leaving is detected only when the user sits up, then detection timing is early, but false alarms increase due to sitting unrelated to leaving the bed
Solution Approach 1:
The system dynamically adjusts detection criteria based on the user's movement patterns. The bed-leaving behavior detection member analyzes the trajectory and speed of the sitting position center of gravity, distinguishing between casual sitting movements and purposeful bed-leaving attempts by evaluating whether the movement direction and velocity align with exiting the bed.
3Measurement precision
If the sitting position center of gravity movement volume exceeds a threshold, then bed-leaving behavior is detected, but the system may miss cases where the user moves slowly or incrementally
Solution Approach 1:
The system employs periodic sampling and accumulation of center of gravity movement data over time. Instead of relying on a single threshold exceedance, the bed-leaving behavior detection member continuously monitors and accumulates movement vectors, detecting bed-leaving behavior even when individual movement increments are small, by recognizing the cumulative pattern and directionality of gradual displacement.
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 detection of bed-leaving behavior before the user leaves the bed, reducing the risk of false alarms and ensuring timely caregiver notification, thereby preventing accidents.
Implementation Method 1
a pressure sensor arranged on the bed
Data Source
AI summary
A bed-leaving sensor for detecting bed-leaving by a user on a bed, including: a sitting position detection member that detects a sitting position of the user based on a detection value of a pressure sensor arranged on the bed; and a bed-leaving behavior detection member that detects bed-leaving behavior of the user with at least one of the following as a condition: (i) the sitting position being detected within a preset bed-leaving expectation region, (ii) a movement volume of a sitting position center of gravity which is a center of gravity of the sitting position exceeding a given threshold value within a given time, and (iii) the sitting position center of gravity moving toward a preset bed-leaving range.