Strain Gauge Assembly with Remote Phase Shift Measurement
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Solution Overview
Problem
Conventional strain gauge systems require amplifiers close to the sensor, increasing complexity, cost, and weight, and are susceptible to noise, especially in applications with limited space.
Innovation Solution
A strain gauge assembly that uses a Wheatstone bridge configuration with an excitation signal generator and phase shifting circuitry to determine phase shifts in the excitation signal, converting these phase shifts into square signals to measure strain without the need for amplifiers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If amplification components are located close to the strain gauge, then noise susceptibility is reduced, but device complexity, cost, and weight increase
Solution Approach 1:
The patent extracts the amplification components from the sensor assembly and relocates them to a remote location. The strain gauge itself remains simple and compact, while the complex amplification circuitry is separated out and placed elsewhere, connected via cables. This resolves the contradiction by removing the source of complexity, weight, and cost from the sensor assembly while maintaining low noise susceptibility through proper signal routing.
Solution Approach 2:
The system is divided into separate functional modules: the strain gauge sensor assembly and the amplification components. This segmentation allows each part to be optimized independently - the sensor remains simple and lightweight while the complex amplification functions are located remotely, reducing the complexity burden on the sensor assembly itself.
2Object-affected harmful factors
If amplification components are located close to the strain gauge, then noise susceptibility is reduced, but weight increases
Solution Approach 1:
The heavy amplification components are extracted from the sensor assembly and relocated to a remote position. This significantly reduces the weight of the moving sensor assembly while the amplification functions are performed by equipment already present at the remote location, such as existing audio equipment or measurement systems.
3Object-affected harmful factors
If amplification components are located close to the strain gauge, then noise susceptibility is reduced, but cost increases
Solution Approach 1:
The patent leverages existing universal equipment at the remote location (such as audio amplifiers, mixers, or measurement systems) to perform the amplification function. This eliminates the need to purchase and install dedicated amplification components with the sensor, significantly reducing cost while still achieving low noise susceptibility through the remote configuration.
4Measurement precision
If amplification components are located close to the strain gauge, then signal quality is maintained, but space requirements increase
Solution Approach 1:
The amplification components are extracted from the compact sensor assembly and placed in a remote location where space is available. This maintains signal quality by keeping the strain gauge simple and stable, while the remote amplification equipment occupies space that does not constrain the sensor installation, particularly in applications like aircraft where sensor space is limited.
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
This solution allows for remote location of the measurement circuitry, reducing noise susceptibility and complexity, while maintaining high accuracy and reliability, and is suitable for applications with limited space.
Implementation Method 1
Essentially, the ratio induced by the change in resistance acts as a voltage divider which provides a differential output value Vout indicative of the strain being measured
Implementation Method 2
phase shifting circuitry arranged to determine phase shifts in the excitation signal responsive to changes in resistance of the two resistive elements
Implementation Method 3
an end stage comprising shaping circuitry to convert sine phase shifted signals into square signals
Data Source
AI summary
A strain gauge assembly includes: a strain gauge comprising a plurality of resistive elements connected as a Wheatstone bridge or half Wheatstone bridge; an excitation signal generator arranged to provide an excitation signal to two resistive elements of the strain gauge; phase shifting circuitry arranged to determine phase shifts in the excitation signal responsive to changes in resistance of the two resistive elements and an end stage configured to output a measure indicative of the phase shift as an indication of strain on the assembly.