Bed Exit Detection with Obstruction-Aware Force Compensation
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Solution Overview
Problem
Existing exit detection systems in person support apparatuses, such as hospital beds and stretchers, often inaccurately detect patient exit due to obstructions exerting forces on force sensors, leading to unreliable alerts or failures in detection.
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 alarms 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 uses force sensors to detect patient movement, then it can monitor patient position and trigger exit alerts, but obstructions exerting forces on the sensors causes false alerts and unreliable detection
Solution Approach 1:
The patent introduces an intermediary obstruction detection system that acts as a mediator between the obstruction and the exit detection system. This separate system detects obstructions and provides signals to the exit detection system, allowing it to distinguish between forces caused by obstructions and forces caused by patient movement, thereby preventing false alerts while maintaining reliable exit detection
Solution Approach 2:
The patent segments the detection function into two independent systems: an obstruction detection system and an exit detection system. Each system has its own sensors and processing logic, allowing them to independently analyze forces and make separate determinations. This segmentation prevents the obstruction detection system from interfering with the exit detection system's ability to accurately monitor patient movement
2Productivity
If the system continuously monitors force sensor outputs for exit conditions, then it can provide real-time exit detection, but obstructions cause false alerts that reduce system accuracy
Solution Approach 1:
The obstruction detection system provides continuous feedback to the exit detection system about the presence of obstructions. This feedback mechanism allows the exit detection system to adjust its interpretation of force sensor readings in real-time, maintaining high responsiveness for actual patient exits while filtering out false alerts caused by obstructions through the feedback information
3Ease of operation
If the exit detection system reacts to force changes without obstruction awareness, then it maintains simple operation, but it generates false alerts when obstructions are present
Solution Approach 1:
The patent merges the obstruction detection system and exit detection system into a coordinated integrated system. While maintaining the operational simplicity of the exit detection system, it combines the obstruction detection capability to provide accurate context about force changes. The merged system automatically processes obstruction information to distinguish between genuine exit conditions and obstruction-induced false alerts
Data Source
AI summary
A person support apparatus includes an exit detection system having a plurality of force sensors that detect the weight of an occupant positioned on a support surface and an obstruction detection system having one or more obstruction sensors. The exit detection system 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.