Passive Temperature Error Compensation for Strain Gauge Sensors
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Solution Overview
Problem
Strain gauge pressure sensors in high-temperature environments face significant output errors due to temperature variations, which existing active compensation circuits struggle to address effectively, especially in expensive and resource-intensive systems that often require separate temperature sensors and microcontrollers.
Innovation Solution
A passive temperature compensation circuit using a Wheatstone bridge configuration with span, zero offset, and compensation resistors, which are calibrated and modeled to minimize output errors across selected temperature and pressure ranges, eliminating the need for active circuitry and separate temperature sensors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If active compensation circuits are used to minimize temperature error, then measurement precision is improved, but device complexity and cost increase due to requiring temperature sensors and microcontrollers
Solution Approach 1:
The patent extracts the temperature sensing function from separate temperature sensors and microcontrollers and integrates it directly into the strain gauge sensor element itself. The strain gauge sensor is designed to simultaneously sense both strain and temperature, eliminating the need for separate active compensation components and reducing overall device complexity while maintaining measurement precision.
Solution Approach 2:
The patent merges the temperature sensing capability with the strain gauge sensor by configuring the strain gauges in a Wheatstone bridge arrangement where temperature effects are detected alongside strain effects. This combination allows the same sensor element to provide both primary measurement and temperature compensation data, reducing device complexity.
2Measurement precision
If active compensation circuits are used to minimize temperature error, then measurement precision is improved, but cost increases due to additional components
Solution Approach 1:
The patent removes the need for expensive separate temperature sensors and microcontrollers by extracting the temperature sensing function and embedding it within the strain gauge sensor element itself, thereby reducing component count and manufacturing cost while maintaining measurement precision.
Solution Approach 2:
The strain gauge sensor performs self-compensation by using its own output signals to detect temperature effects and apply corrections, eliminating the need for external active compensation systems and reducing manufacturing cost.
3Adaptability or versatility
If strain gauge sensors are used in high temperature environments, then adaptability is improved, but measurement precision deteriorates due to output errors up to 20% or greater
Solution Approach 1:
The patent implements feedback by using the strain gauge sensor output to detect temperature-induced resistance changes and automatically compensating for these changes in real-time. The system continuously monitors the sensor output and applies corrections based on the detected temperature effects, maintaining measurement precision across a wide temperature range.
Solution Approach 2:
The patent compensates for temperature effects by changing the interpretation parameters of the sensor output. By analyzing the resistance changes in the Wheatstone bridge configuration and distinguishing between strain-induced and temperature-induced changes, the system adjusts measurement parameters to maintain accuracy across varying temperatures.
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 provides effective temperature error compensation for strain gauge pressure sensors, reducing output errors by a factor of 10 or more within the selected temperature and pressure spans, while integrating the compensation circuit with the sensor as a single, cost-effective package.
Implementation Method 1
Strain gauge sensors may be utilized to sense strain based on a change in electrical resistance of the strain gauge
Implementation Method 2
The sensor includes four strain gauges configured in a Wheatstone bridge
Data Source
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AI summary
A sensor system includes a plurality of strain gauges (12) and a passive compensation circuit (30). The plurality of strain gauges are configured to provide an output voltage indicative of a sensed pressure using an input voltage. The passive compensation circuit that includes a span resistor (RS1), first and second compensation resistors (RC1, RC2), and a zero offset resistor (RTZ1). The span resistor is connected between an input voltage and the pressure sensor and is configured to control a range of an output voltage for a pressure range of the pressure sensor. The first and second compensation resistors are operatively connected in parallel with the pressure sensor and are configured to control current provided to the pressure sensor. The zero offset resistor is operatively connected between the first and second compensation resistors and the pressure sensor and is configured to control a base value of the output voltage for zero pressure.