Force Sensor with Deformable Spring Bodies for Uneven Load Measurement
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Solution Overview
Problem
Existing sensors struggle to accurately measure forces that are unevenly distributed over a measuring surface, particularly in applications like bathroom scales and shoe insoles, due to inaccuracy in full-surface sensor elements and limited measurement capabilities when the force distribution exceeds the sensor surface.
Innovation Solution
A sensor design featuring a deformable measuring surface and counter-surface with spring bodies made of silicone rubber, connected by elastic fastening means, allowing for linear force measurement independent of force distribution through capacitive or inductive measuring elements, which can be corrected for temperature effects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If rigid surfaces are used for measuring surface and counter-surface, then structural stability is improved, but measurement accuracy deteriorates when force is unevenly distributed
Solution Approach 1:
The patent applies flexible measuring surfaces and counter-surfaces made of elastomeric materials instead of rigid surfaces. These flexible surfaces can deform elastically under applied forces, allowing them to conform to uneven force distributions while maintaining measurement accuracy. The flexibility enables the surfaces to adapt to different loading conditions without compromising structural integrity.
Solution Approach 2:
The patent changes the physical parameter of the measuring surfaces from rigid to elastomeric, allowing the material properties to adapt to varying force conditions. The elastomeric material's ability to change shape and deform elastically enables accurate measurement of unevenly distributed forces while maintaining overall structural stability through the sensor housing.
2Area of stationary object
If the total sensor surface is too small, then device compactness is improved, but measurement accuracy deteriorates when forces are distributed beyond the measuring surface
Solution Approach 1:
The patent divides the sensor into multiple independent spring bodies arranged in an array, where each spring body can independently measure local force. This segmentation allows the sensor to accurately capture unevenly distributed forces across the measuring surface by summing the individual measurements from each spring body, thereby maintaining measurement accuracy even with a compact overall sensor design.
3Adaptability or versatility
If elastic materials are used for spring bodies, then adaptability to different force distributions is improved, but manufacturing precision deteriorates due to material variability
Solution Approach 1:
The patent utilizes the elastomeric material's inherent properties of flexibility and elastic recovery to achieve adaptability to different force distributions. By selecting appropriate elastomeric compounds with consistent durometer ratings and controlling curing parameters, the patent maintains manufacturing precision while benefiting from the material's ability to conform to various loading conditions and maintain linear elastic behavior.
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 and independent measurement of total force regardless of uneven force distribution, suitable for various applications including shoe insoles and human limb measurements, with improved precision and adaptability to different force ranges.
Implementation Method 1
the spring bodies have a linear characteristic even within measuring ranges that are small in terms of area
Implementation Method 2
the deformation of the sensor being capacitively measurable
Implementation Method 3
the sensors consist of capacitors, that is to say of a large number of capacitor surfaces which are constructed in the form of a matrix and are scanned individually as a matrix
Implementation Method 4
the measuring surface and/or the counter-surface are preferably designed as a textile material or comprise a textile material
Data Source
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AI summary
The invention relates to a sensor for electrically measuring a force acting on the sensor, which force is distributed unevenly over a measurement surface (10) of the sensor, wherein an electrical force measurement signal is generated. A flat spring device (20) is provided between the measurement surface (10) and a counter surface (11). A first measurement element is arranged in or on the measurement surface (10) and a second measurement element is arranged in or on the counter surface (11), in such a way that the measurement elements substantially completely cover the respective surfaces. The measurement elements, e.g., capacitor plates, are designed in such a way that the measurement signal can be generated from a distance between the measurement elements. The spring device (20) has a plurality of incompressible but elastic spring bodies (21 to 213), which are arranged so as to be separated from each other by gaps (22) and in such a way that each spring body (21 to 213) can deform into the gaps (22) and thus in a space-occupying manner when loaded with the force or a fraction of said force. This measuring assembly allows for the measurement of unevenly distributed forces between bodies, which can be shaped very differently.