Torquemeter Calibration Without Temperature Sensors
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Solution Overview
Problem
Existing torsion torque meters require knowledge of the shaft temperature and material behavior model to calculate torque, making the calibration process complex and temperature-dependent.
Innovation Solution
A method involving four sets of measurements across different torque and temperature conditions allows the torsion torque meter to calculate torque without needing to determine the shaft temperature, using calibration data to determine the torque value from angular deviations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the torsional torque meter uses a database with torque values at different temperatures, then the torque calculation is more accurate, but the device complexity and calibration complexity increase
Solution Approach 1:
The patent extracts the temperature dependency from the torque measurement system by using two separate torque meters: a reference torque meter whose output is temperature-independent, and a torsional torque meter whose output contains temperature-dependent information. This allows the temperature effect to be isolated and removed through calibration, simplifying the overall system while maintaining accuracy.
Solution Approach 2:
The patent introduces a calibration process as an intermediary step that uses the reference torque meter to characterize the temperature behavior of the torsional torque meter. This calibration data acts as a mediator that allows the torsional torque meter to compensate for temperature effects without directly measuring temperature, reducing device complexity.
2Measurement precision
If the torsional torque meter requires shaft temperature determination, then torque can be calculated using material behavior models, but the ease of operation decreases
Solution Approach 1:
The patent makes the torsional torque meter self-sufficient by having it carry out its own calibration using the reference torque meter. The calibration process automatically characterizes the temperature dependency of the torsional torque meter's output, storing this information in look-up tables that the meter uses to compensate for temperature effects during operation, eliminating the need for external temperature measurement equipment.
Solution Approach 2:
The patent changes the operational parameters by using two different torque ranges during calibration (first and second predetermined torque ranges) and two different temperatures (first and second temperatures). This allows the system to capture the non-linear temperature dependency of the torsional torque meter across its operating range, improving accuracy while maintaining operational simplicity.
3Measurement precision
If four sets of measurements are taken at different torque and temperature conditions, then calibration accuracy is improved, but the loss of time increases
Solution Approach 1:
The patent uses four measurement points (excessive action) to fully characterize the temperature dependency of the torsional torque meter across its operating range. By taking measurements at two different temperatures and two different torque ranges, the calibration captures sufficient information to accurately compensate for temperature effects throughout the meter's operational envelope, ensuring high calibration accuracy.
Solution Approach 2:
The patent performs the calibration process in advance during manufacturing or maintenance periods when the turbomachine can be stationary. The four sets of measurements are taken systematically, with temperature stabilization between measurements, to establish comprehensive look-up tables that will be used during normal operation, eliminating the need for repeated calibration during flight operations.
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 method simplifies the calibration process, achieving precision comparable to a reference torquemeter, eliminating the need for temperature knowledge and material behavior models, and can be performed quickly on a test bench without dismantling the turbomachine.
Implementation Method 1
a measurement of the torsional deformation of the shaft, this deformation being notably a function of the transmitted torque
Data Source
Figure 1~2
Figure 3~4
Figure 5
AI summary
The invention relates to a method for calibrating a torquemeter, comprising a power shaft, a reference shaft, a measurement device for measuring the first and second angular deviations between the angular reference points belonging to the power and reference shafts, a calculation unit for determining, from the first and second angular deviations, a torque value output by the power shaft, wherein said method comprises: placing the torquemeter in a first state; carrying out first and second measurements in which the first and second angular deviations (ocmi, pmi) are determined, and the torque (TQmi) output by the power shaft are measured using a reference torquemeter; placing the torquemeter in a second state; carrying out a second set of measurements in which the first and second angular deviations (am2; Pm2) are determined, and the torque (TQm2) output by the power shaft is measured; placing the torquemeter in a third state; carrying out a third set of measurements in which the first and second angular deviations(0^3, Pm3) are determined, and the torque (TQm3) output by the power shaft is measured; placing the torquemeter in a fourth state; carrying out a fourth set of measurements in which the first and second angular deviations ((½4, ßp??) are determined, and the torque (TQm4) ouptut by the power shaft is measured; and calibrating the calculation unit on the basis of the first, second, third and fourth sets of measurements.