Force-Sensor Bed Exit Detection Under Obstruction Interference
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Solution Overview
Problem
Existing person support apparatuses, such as hospital beds and stretchers, face reliability issues with exit detection systems due to obstructions exerting forces on force sensors, leading to incorrect exit alerts or failures to issue alerts when a patient is about to exit.
Innovation Solution
The system includes an obstruction sensor that detects contact with obstructions, switching the exit detection system to a disarmed state to prevent false alerts, and compensates for obstruction-induced errors by adjusting the calculated center of gravity and zone boundaries.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the exit detection system continuously monitors force sensor outputs to detect patient exit, then timely exit detection is achieved, but false exit alerts occur when obstructions exert forces on the force sensors
Solution Approach 1:
The system performs preliminary actions by detecting obstructions before they cause false exit alerts. The obstruction detection mechanism identifies when an obstruction is present on the person support apparatus, and the system proactively adjusts exit detection sensitivity or disables exit alerts in response, preventing false alerts before they occur.
Solution Approach 2:
The system introduces an intermediary obstruction detection mechanism that mediates between the force sensors and the exit detection logic. This intermediary layer distinguishes between forces caused by patient movement and forces caused by obstructions, allowing the system to accurately interpret sensor data despite obstruction interference.
2Reliability
If the system disables exit detection when obstructions are detected, then false alerts are prevented, but legitimate exit detection may be missed
Solution Approach 1:
The system dynamically adjusts its exit detection behavior based on obstruction detection status. Rather than statically disabling exit detection, the system modifies its sensitivity thresholds and alert criteria in real-time according to the presence or absence of obstructions, maintaining detection capability while adapting to changing conditions.
Solution Approach 2:
The system changes operational parameters of the exit detection algorithm based on obstruction detection. When obstructions are detected, the system adjusts sensitivity thresholds, force thresholds, or time-window parameters to distinguish legitimate patient movement from obstruction-induced force changes, preserving exit detection capability while maintaining accuracy.
Data Source
AI summary
A person support apparatus, such as a bed, stretcher, cot, recliner, or the like, includes an exit detection system having a plurality of force sensors that support the weight of an occupant positioned on a support surface and obstruction detection system having one or more obstruction sensors. The force sensors are part of an exit detection system that issues an alarm when the occupant exits, or is about to exit, the person support apparatus. The bed exit system can react to detection of an obstacle. The distribution of weight applied to the force sensors is used to determine if the occupant is about to exit the person support apparatus. Compensation is made to the exit detection system for changes in the weight distribution that are not caused by movement of the occupant. Such changes may be due to not only movement of the person support apparatus or components thereof, but obstacles encountered by the person support apparatus or components thereof.