Electric Bed Angle Control to Prevent Patient Displacement
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Solution Overview
Problem
Existing electrically operated beds for nursing care cause patient displacement and discomfort during back-raising and back-lowering operations, relying on subjective carer intervention and not optimizing for individual patient or mattress attributes.
Innovation Solution
An electrically operated bed with a control unit that adjusts back and knee angles according to pre-set patterns stored in a memory unit, allowing for selection of patterns based on patient height, mattress characteristics, or user preferences, to minimize displacement and discomfort.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If separate back-raising and knee-raising operations are controlled independently by carer, then the operation flexibility is maintained, but the patient displacement and discomfort cannot be reliably prevented due to carer subjectivity
Solution Approach 1:
The control unit monitors the back angle and knee angle in real-time during back-raising and back-lowering operations, comparing actual angles with target angles from pre-set patterns. This feedback mechanism ensures that the bed adjusts according to optimal patterns that prevent patient displacement and discomfort, eliminating reliance on carer subjectivity while maintaining operational flexibility through automated control.
Solution Approach 2:
Optimal back-raising and back-lowering patterns are pre-calculated and stored in the control unit before operations begin. These patterns define the relationship between back angle and knee angle at various stages of movement. During operation, the control unit automatically follows these pre-established patterns, ensuring reliable prevention of patient displacement and discomfort without requiring real-time carer judgment.
2Device complexity
If a fixed back-raising pattern is used, then the control simplicity is maintained, but the adaptability to different patient physical attributes and mattress characteristics is reduced
Solution Approach 1:
The control unit allows dynamic selection of different pre-set patterns based on patient attributes (such as body weight, height, mobility level) and mattress characteristics (such as firmness, thickness). The system transitions from a static fixed pattern to a dynamic adaptive pattern selection, where the appropriate pattern is chosen before operation based on measured or input patient and mattress parameters, maintaining control simplicity while achieving adaptability.
Solution Approach 2:
The system changes operational parameters (back angle trajectory, knee angle trajectory, timing of movements) based on patient and mattress attributes. Different patterns define different parameter profiles for the back-raising and back-lowering operations. By selecting patterns matched to specific patient-mattress combinations, the system adapts to varying physical conditions while keeping the control interface simple through automated parameter selection.
3Device complexity
If back-raising operation is performed without coordinated knee-raising, then the device complexity is reduced, but the patient discomfort and circulatory disorders increase due to muscle-skin displacement
Solution Approach 1:
The control unit merges the control of back-raising and knee-raising operations into a coordinated sequence. During back-raising, the knee bottom is automatically raised according to the pre-set pattern to support the patient's lower body. This combined control ensures that muscle-skin displacement is minimized and circulatory disorders are prevented, while the automated coordination keeps the control mechanism complexity manageable through integrated control logic.
Solution Approach 2:
The control unit acts as an intermediary that coordinates between the back-raising actuator and knee-raising actuator. It manages the timing and magnitude of knee-raising in response to back-raising movements, ensuring optimal support to the patient's body. This intermediary control function reduces patient discomfort and circulatory risks by preventing harmful muscle-skin displacement, while maintaining reasonable device complexity through automated mediation.
Data Source
AI summary
A control unit controls a drive unit so that a back angle α, which is an elevation angle of a back bottom, and a knee angle β, which is an elevation angle of a knee bottom, change according to a pre-set pattern. The control unit comprises a memory unit for storing a plurality of patterns of linking a coordinate point (0,0) in a (α,β) coordinate, in which each of the bottoms is in a horizontal state, and a coordinate point (α0, β0), in which the back bottom is raised, with a plurality of points; a selection unit for selecting one pattern from the plurality of patterns stored in the memory unit; and a computation unit for controlling the drive unit so that the back angle α and the knee angle β change according to the pattern selected by the selection unit. Therefore, the patient can be prevented from being displaced on the bed and from being subjected to a sense of pressure on their stomach or chest.