Stretchable Strain Gauge Circuit for Noise-Resistant Hinge Sensing

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Solution Overview

Problem

Existing stretchable devices face challenges in accurately detecting strain on hinges due to noise input from voltage and signal lines, particularly when they have biaxial structures that extend in two directions, leading to inaccurate strain detection.

Innovation Solution

A stretchable device design with a housing that accommodates a resin base member, strain gauges, and electrical wiring, including longitudinal and lateral strain gauges, and a Wheatstone bridge circuit to detect strain accurately by minimizing noise interference.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If voltage lines and signal lines are disposed on the hinges to detect strain, then strain detection capability is enabled, but noise is input to the signal line causing inaccurate detection

Engineering Contradiction:

Improvestrain detection accuracyVSAvoidnoise input to signal line

Core Design Contradiction:

Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The patent converts the harmful noise effect into a useful measurement signal by placing strain gauges on both sides of the hinge. The noise affects both strain gauges equally, creating equal resistance changes that can be subtracted out. The harmful noise becomes a common-mode signal that reveals itself through differential measurement, allowing accurate strain detection despite the presence of noise.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

The patent introduces an intermediary measurement approach using a differential circuit that measures the difference between two strain gauge signals. This intermediary differential measurement process eliminates the common noise component while preserving the actual strain signal, acting as a mediator between the noisy sensor outputs and the final accurate measurement.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Measurement precision

If strain gauges are disposed on the hinges for strain detection, then load detection capability is enabled, but the biaxial structure of hinges makes conventional Wheatstone bridge circuits inapplicable

Engineering Contradiction:

Improveload detection capabilityVSAvoidcircuit configuration complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent segments the measurement function into two independent directional measurements using separate strain gauges for longitudinal and lateral directions. Each direction is measured independently with its own strain gauge and circuit path, simplifying the overall measurement system while maintaining accuracy for biaxial structures.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent creates a universal measurement approach that works for biaxial hinge structures by using a flexible measurement circuit that can handle strain gauges oriented in any direction. The measurement system is designed to be multi-functional, accommodating both longitudinal and lateral strain measurements with the same basic circuit architecture.

Inventive Principle:

Principle #6Universality (Multi-functionality)

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 design enables precise detection of strain on hinges by isolating strain gauges from noise, ensuring accurate measurement of resistance changes using a Wheatstone bridge circuit configuration.

Implementation Method 1

strain gauges... configured to detect an amount of change in resistance of each of the strain gauges

Methodology Applied

Scientific EffectPiezoresistive effect: Piezoresistive Effect

Implementation Method 2

Wheatstone bridge circuit to detect strain accurately by minimizing noise interference

Methodology Applied

Scientific EffectWheatstone bridge: Wheatstone Bridge

Data Source

PatentUS12517554B2Stretchable device

Publication Date: 2026.01.06 MAGNOLIA WHITE CORP

AI summary

A stretchable device includes a resin base member, strain gauges, and electrical wiring. The strain gauges include a longitudinal strain gauge and a lateral strain gauge. The electrical wiring includes an electrical wiring line for longitudinal strain and an electrical wiring line for lateral strain. The electrical wiring line for longitudinal strain and the electrical wiring line for lateral strain each include a first potential line, a second potential line, a coupling line, a first signal line, and a second signal line. The first signal line detects a third potential at a first coupling point where the second end of the corresponding strain gauge is coupled to the second potential line. The second signal line detects a fourth potential at a midpoint of the coupling line. The amount of change in resistance of each strain gauge is detected based on a difference between the third potential and the fourth potential.