IR Beam Filter for Patient Lift Obstacle Detection Accuracy
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Solution Overview
Problem
Existing patient support apparatuses, such as hospital beds, lack effective obstacle detection systems that prevent obstacles from being crushed or injured during the vertical movement of the elevating frame, as they fail to accurately detect obstacles within a predetermined distance due to light beam reflections off the frames.
Innovation Solution
Incorporating an obstacle detection system with an emitter and a receiver, coupled with an integral beam filter that narrows the light beam to prevent reflections, ensuring the light beam only reaches the receiver if an obstacle is not within the detection range, thereby disabling the lifting mechanism if an obstacle is detected.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a light beam is used for obstacle detection, then the detection range is extended, but light beam reflections off the frames cause false detection and reduce measurement precision
Solution Approach 1:
An optical filter is introduced as an intermediary component between the light source and the receiver. This filter selectively transmits the detection wavelength while blocking reflected light, thereby eliminating the harmful reflection effect and improving obstacle detection accuracy.
Solution Approach 2:
The system changes the wavelength parameter of the light beam to a specific infrared wavelength that is effectively blocked by the optical filter when reflected. By controlling the wavelength parameter and the filter's transmission characteristics, the system prevents reflected light from reaching the receiver while maintaining detection of obstacles within the predetermined distance.
2Ease of operation
If the elevating frame is moved to a lowered position for patient entry/exit, then ease of operation is improved, but obstacles may be crushed or injured during movement
Solution Approach 1:
The obstacle detection system performs preliminary detection before the elevating frame begins its downward movement. By detecting obstacles in advance within the predetermined distance, the system can prevent the frame from moving, thereby avoiding crushing or injury to obstacles while still allowing easy patient entry and exit when the path is clear.
Solution Approach 2:
The system uses optical feedback from the receiver to continuously monitor the presence of obstacles. When an obstacle is detected, the feedback signal triggers the controller to disable the lifting mechanism, preventing harmful movement. This feedback loop ensures safety while maintaining operational convenience.
3Measurement precision
If the light beam is narrowed to prevent reflections, then measurement precision is improved, but the detection range may be reduced
Solution Approach 1:
The system changes the wavelength parameter of the light beam to a specific infrared wavelength and uses an optical filter tuned to this wavelength. This parameter combination allows the beam to be sufficiently narrow to prevent reflections while maintaining adequate detection range for the predetermined distance, resolving the contradiction between precision and range.
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
Effectively prevents the elevating frame from moving towards a lowered position if an obstacle is present, ensuring safety by blocking the light beam reflections and providing accurate obstacle detection within a predetermined distance, thus preventing potential harm to the obstacle.
Implementation Method 1
an emitter including a light source configured to emit a light beam
Implementation Method 2
the beam filter is configured to narrow the light beam within a predetermined distance to prevent the light beam from being reflected off the first frame and the second frame and reaching the receiver
Data Source
Figure 1~2
Figure 3~4
Figure 5
AI summary
A patient-support apparatus includes a first frame and a second frame movable relative to the first frame. The patient-support apparatus further includes an obstacle detection device and related method for detecting an obstacle between the first frame and the second frame of the patient-support apparatus.