Piezoelectric Substrate Grid for Bed Position Detection
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Solution Overview
Problem
Existing bed devices with pressure sensors cannot accurately detect the position or lopsided positioning of a person on the bed, as they either incorporate piezoelectric cables in a wavy pattern or elongate tape-shaped sensors across the bed width, limiting their ability to detect lateral positioning.
Innovation Solution
A human body detection device featuring line-shaped piezoelectric substrates intersecting the direction of pressure applied, with each substrate having an elongate conductor and helically wound piezoelectric material, capable of detecting pressure in a radial direction, and a processor to analyze output signals for position determination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If piezoelectric cable is arranged in a wavy pattern in the mattress, then the presence or absence of the person in bed can be detected, but it is not possible to detect lopsided positioning on the bed
Solution Approach 1:
The detection system is divided into multiple independent piezoelectric substrate regions arranged in a grid pattern. Each region can independently detect pressure, enabling the system to determine both presence and specific position (including lopsided positioning) by analyzing which regions are activated and their relative signal strengths.
Solution Approach 2:
The piezoelectric substrates are arranged in a two-dimensional grid pattern with multiple rows and columns, transitioning from one-dimensional linear arrangements. This dimensional expansion allows the system to detect position in both longitudinal and lateral directions, enabling detection of lopsided positioning that was impossible with single-line arrangements.
2Measurement precision
If elongate tape shaped piezoelectric sensor is installed across the bed in the width direction, then the presence or absence of the person in bed can be detected, but it is not possible to detect lopsided positioning on the bed
Solution Approach 1:
The single elongate tape sensor is segmented into multiple smaller piezoelectric substrate regions arranged in a grid. This segmentation allows the system to detect pressure distribution across different areas, enabling determination of position and detection of lopsided positioning by comparing signal strengths across the segmented regions.
Solution Approach 2:
The sensor arrangement transitions from a single-line configuration to a two-dimensional grid pattern. This dimensional change provides coverage in both width and length directions, allowing the system to detect not only presence but also specific position and lopsided positioning by analyzing the spatial distribution of pressure signals.
3Measurement precision
If piezoelectric substrates are arranged to detect pressure in radial direction, then position detection capability is improved, but the device structure becomes more complex
Solution Approach 1:
Each piezoelectric substrate is designed with specific local properties including an elongate conductor and helically wound piezoelectric material that generate radial pressure detection capability. This localized optimization allows each substrate to function as an independent position-sensing element, improving overall detection precision while maintaining manageable complexity through modular repetition of the same unit structure.
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
Enables accurate detection of a person's position on the bed, including lopsided positioning, by comparing output signals from adjacent piezoelectric substrates, enhancing monitoring and care in hospital or care facility settings.
Implementation Method 1
line-shaped piezoelectric substrates respectively provided in each of plural regions in a plate material intersecting a direction of pressure received from a human body
Implementation Method 2
an elongate piezoelectric material helically wound in one direction around the conductor, and pressure input to the piezoelectric material is detected from a difference in potential between the conductor and the piezoelectric material
Data Source
AI summary
A human body detection device including line-shaped piezoelectric substrates respectively provided in each of a plurality of regions in a plate material intersecting a direction of pressure received from a human body, and provided such that an axial direction of each of the piezoelectric substrates runs along the plate material so as to detect pressure applied in a radial direction of the piezoelectric substrate, memory, and a processor coupled to the memory. The processor is configured to be capable of detecting an output signal from each of the piezoelectric substrates.