Angular Displacement Sensor with Compliant Elastomer
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Solution Overview
Problem
Conventional capacitive strain sensors are limited in their ability to measure bending movements in multiple planes and are prone to damage from excessive strain, restricting their flexibility and potential uses, especially when measuring joints with multiple degrees of freedom.
Innovation Solution
An angular displacement sensor system featuring a flexible elongated structure with embedded compliant capacitors that can bend in multiple orientations without restraining members, utilizing elastomer-based materials and conductive fillers to maintain electrical conductivity and flexibility, allowing for unrestricted bending movement and strain sensing in multiple planes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional capacitive strain sensors are used to measure bending, then they can detect strain in a single plane, but they are limited in measuring multiple planes and are prone to damage from excessive strain
Solution Approach 1:
The patent employs a flexible elastomeric beam structure that can bend in multiple planes without rigid constraints. The compliant electrode layers and dielectric material are integrated into this flexible substrate, allowing the sensor to accommodate multi-planar bending movements while maintaining electrical functionality and resisting damage from excessive strain through the inherent flexibility of the elastomeric material.
Solution Approach 2:
The sensor utilizes composite material construction combining elastomeric dielectric material with conductive electrode layers. This composite structure provides both the flexibility needed for multi-planar bending and the electrical properties required for strain detection, resolving the contradiction between versatility in measurement and reliability under strain.
2Reliability
If the sensor structure is made rigid to maintain electrical circuit integrity, then electrical conductivity is preserved, but flexibility and bendability are reduced
Solution Approach 1:
The patent employs flexible conductive electrode layers embedded in an elastomeric matrix that maintains electrical continuity while allowing the structure to bend freely in multiple planes. The conductive material is distributed throughout the flexible substrate, ensuring circuit integrity is preserved despite the lack of rigid structural support.
Solution Approach 2:
The sensor design accepts that physical parameters such as electrode spacing and surface area will change during bending, but the electrical circuit remains intact through the flexible conductive pathways. The system measures strain by detecting these parameter changes rather than requiring rigid geometric maintenance.
3Reliability
If restraining members are added to prevent excessive strain, then sensor durability is improved, but flexibility and range of motion are limited
Solution Approach 1:
The elastomeric beam structure inherently resists excessive strain through its material properties rather than mechanical restraints. The flexible substrate and embedded conductive layers work together to accommodate large deformations while maintaining electrical functionality, eliminating the need for restraining members that would limit range of motion.
Solution Approach 2:
The sensor structure is designed to be self-protecting through its flexible material composition. The elastomeric dielectric and conductive electrode layers are integrated into a configuration that naturally accommodates strain without requiring external restraining mechanisms, allowing the sensor to both protect itself and maintain full flexibility.
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
The sensor system effectively measures angular displacement in multiple orthogonal planes without breaking the electrical circuit, providing accurate data on joint movements and flexibility, suitable for various anatomical and mechanical applications.
Implementation Method 1
This arrangement forms a capacitor whose capacitance depends in part on the distance between the conductive layers and the change in surface area of the compliant conducting layers. The strain and/or compression of the dielectric layer changes the capacitance of the sensor, which can be detected by a sensing system.
Implementation Method 2
an elongated structure extending between a first end and a second end, the elongated structure being an elastomer based compliant material that is flexible and bendable
Implementation Method 3
a first conductive layer embedded within and extending from the first end to the second end along a longitudinal length of the elongated structure to form a first electrode of the first compliant capacitor
Data Source
Figure 1A
Figure 1B~1C
Figure 2A~2B
AI summary
Disclosed is a sensing device that includes a flexible substrate having an elongated structure extending between a first end and a second end, the elongated structure being compliant material that is flexible and bendable from a linear, non-bent position to multiple bendable positions. The sensing device also includes a first compliant strain sensing element embedded within the compliant material and extending between the first end and the second end along a longitudinal length of the elongated structure. The first compliant strain sensing element includes a second compliant material that is flexible and bendable, where an electrical property of the first compliant strain sensing element changes in proportion to an applied strain on the elongated structure.