Patient Support Pinch Detection via Dynamic Thresholds
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Solution Overview
Problem
Existing patient support apparatuses face challenges in accurately detecting obstructions during the movement of movable components, often resulting in false indications or failure to detect pinch events, which can lead to accidents or damage.
Innovation Solution
A control system that operates in multiple modes to detect pinch events by analyzing sensor feedback from actuator systems, such as motor current and speed, with adjustable thresholds to differentiate between potential obstructions based on the likelihood of small or large objects, thereby enhancing sensitivity and accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single detection threshold is used for all operating conditions, then the detection system is simple to implement, but it results in false alarms or failure to detect pinch events in different operational regions
Solution Approach 1:
The patent implements dynamic threshold adjustment by dividing the operating range into multiple regions (first, second, and third regions) with different detection thresholds. The control system selectively applies appropriate thresholds based on the current operating region, allowing the detection criteria to adapt dynamically to different operational conditions rather than using a fixed single threshold throughout all operations.
Solution Approach 2:
The patent changes the detection parameter (current threshold) based on operating conditions by establishing different current thresholds for different operating regions. The first threshold is applied in the first region, the second threshold in the second region, and the third threshold in the third region, thereby optimizing detection accuracy for each specific operational context.
2Measurement precision
If multiple detection thresholds are used for different operating regions, then detection accuracy is improved, but the control system becomes more complex
Solution Approach 1:
The patent segments the operating range into distinct regions (first, second, and third regions) based on motor current characteristics. Each region is associated with specific detection thresholds and criteria, allowing the system to apply simplified region-specific rules rather than complex global analysis, thereby improving precision while managing complexity through structured segmentation.
Solution Approach 2:
The control system dynamically selects which detection threshold and criteria to apply based on the current operating region. This dynamic adaptation allows the system to maintain high detection precision across varying conditions while keeping the implementation relatively simple through rule-based regional classification rather than complex continuous analysis.
3Reliability
If the detection system is highly sensitive to all current variations, then pinch events are detected reliably, but false alarms increase due to normal operational current fluctuations
Solution Approach 1:
The patent applies different detection sensitivities (thresholds) to different operating regions rather than using a uniform high sensitivity across all operations. The first threshold is applied in the first region, the second threshold in the second region, and the third threshold in the third region, allowing each region to have optimized detection parameters that reduce false alarms while maintaining reliability for actual pinch events.
Solution Approach 2:
The detection parameter (current threshold) is changed based on the operating region to balance sensitivity and false alarm reduction. By adjusting the threshold according to the specific operational context, the system maintains reliable pinch detection while tolerating normal current variations that would otherwise trigger false alarms.
4Adaptability or versatility
If a single current threshold is used for obstruction detection, then the system is easy to implement, but it cannot differentiate between small objects (potential pinch events) and large objects (normal obstructions)
Solution Approach 1:
The patent segments detection into multiple criteria based on operating regions. The first detection criterion is applied in the first region, the second detection criterion in the second region, and the third detection criterion in the third region. This segmentation allows the system to differentiate between small objects (potential pinch events) and large objects (normal obstructions) by applying appropriate criteria to appropriate regions, thereby improving adaptability while managing complexity through structured classification.
Solution Approach 2:
The detection parameters (current thresholds and criteria) are changed based on the operating region to enable differentiation between object types. By adjusting the detection parameters according to the specific operational context, the system can identify small objects that may indicate pinch events versus large objects that represent normal obstructions, enhancing detection adaptability.
Data Source
AI summary
Systems and methods for detecting a pinch event or obstruction to a movable component of a patient support. In some embodiments, the patient support apparatus may include a control system capable of controlling one or more actuator systems coupled to one or more movable components of the patient support apparatus. The control system may operate according to one or more modes of operation in controlling the actuator system to move a component from a first position to a second position. In one embodiment, the control system may receive sensor feedback indicative of one or more operating characteristics of an actuator system, and analyze the sensor feedback differently in one mode than in another. In one embodiment, the controller may receive sensor feedback indicative of both a speed of a component coupled to the movable component and a current of power supplied to an electric motor of the actuator system.