Person Support Exit Detection with Adjustable Alert Zones
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Solution Overview
Problem
Existing person support apparatuses, such as hospital beds and stretchers, face issues with inaccurate exit detection systems that lead to false alarms and failures to alert when a patient is about to exit, due to fixed alert zones that do not adapt to changes in the apparatus's condition or occupant's movements.
Innovation Solution
The apparatus includes an exit detection system with adjustable alert and arming zones that adjust based on conditions like deck width, incline angle, and occupant movement, using force sensors and a controller to determine the boundary adjustments, thereby improving accuracy and reducing false alarms.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If fixed alert zones are used in the exit detection system, then the system structure is simple, but the measurement precision of exit detection deteriorates leading to false alarms
Solution Approach 1:
The patent applies the dynamics principle by making the alert zones adjustable and reconfigurable rather than fixed. The controller dynamically modifies the boundaries and parameters of alert zones based on detected conditions such as occupant position, deck width, and incline angle. This allows the system to adapt to changing conditions and improve detection accuracy without requiring multiple physical sensor arrays, thus resolving the contradiction between measurement precision and device complexity.
Solution Approach 2:
The patent implements parameter changes by modifying the geometric parameters (boundaries, size, shape) of alert zones based on detected conditions. The controller adjusts zone parameters in response to changes in deck width, incline angle, and occupant position, enabling the system to maintain high detection accuracy across varying operational conditions while using a single configurable system rather than multiple fixed systems.
2Adaptability or versatility
If the support deck width is adjusted, then the adaptability of the person support apparatus is improved, but the reliability of exit detection deteriorates due to mismatched fixed alert zones
Solution Approach 1:
The system dynamically adjusts alert zone boundaries in response to changes in support deck width. When the deck width is modified, the controller receives feedback and automatically reconfigures the alert zones to match the new dimensions, ensuring continuous reliable exit detection regardless of the deck configuration. This dynamic adaptation resolves the contradiction between adaptability and reliability.
Solution Approach 2:
The patent employs feedback mechanisms where the controller continuously monitors deck width and other operational parameters, then uses this information to adjust alert zone parameters. This closed-loop control ensures that alert zones remain properly aligned with the physical boundaries of the support deck, maintaining detection reliability across all adaptable configurations.
3Reliability
If fixed arming zones are used, then the device complexity is reduced, but the reliability of system arming deteriorates when occupant position varies
Solution Approach 1:
The arming zones are implemented as dynamic, adjustable regions that the controller can reposition and resize based on detected occupant position and other conditions. This allows the system to reliably establish arming zones that accurately reflect the current operational state, improving arming reliability while using software-based adjustment rather than complex mechanical systems.
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
The system provides advanced notification of exit intentions and reduces false alarms by dynamically adjusting alert zones in response to changes in the apparatus's configuration and occupant's position, enhancing the reliability of exit detection.
Implementation Method 1
The exit detection system includes a plurality of force sensors adapted to output signals corresponding to downward forces exerted on the support deck
Data Source
AI summary
A person support apparatus, such as a bed, cot, stretcher, or the like, for a supporting an occupant includes an exit detection system that has, in some embodiments, multiple user-selectable zones. An alert is triggered when the occupant crosses a boundary of the selected zone. A first zone has a boundary that is adjusted based on a condition of the person support apparatus, such as the width of the support deck or other characteristic. A second zone has a boundary that is not adjusted based on the condition of the person support apparatus, but which may have a boundary that is dependent on an initial location of the occupant when the exit detection system is armed. The initial location of the occupant may correspond to a center of gravity of the occupant.