Rotating-Shaft Torque Sensor Correction Using Two Reference Temperatures
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Solution Overview
Problem
Conventional methods for manufacturing torque sensors require extensive testing at multiple temperatures to account for temperature fluctuations, leading to increased manufacturing time and costs without ensuring accurate torque measurement.
Innovation Solution
A method for acquiring a correction value for a torque sensor involves measuring output values at two reference temperatures and using a provisional correction function to determine correction values at additional temperatures, reducing the need for extensive testing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If extensive testing at multiple temperatures is performed to account for temperature fluctuations, then measurement precision is improved, but manufacturing time increases
Solution Approach 1:
The patent applies preliminary action by pre-determining the relationship between temperature and output value through testing at two reference temperatures (first reference temperature and second reference temperature). This pre-established relationship allows for temperature compensation without requiring extensive testing at every possible temperature point during manufacturing, thus reducing manufacturing time while maintaining measurement precision.
Solution Approach 2:
The patent utilizes parameter changes by establishing a mathematical relationship (linear function or polynomial) between temperature parameter and output value parameter. By determining how the output value changes with temperature through testing at reference temperatures, the system can predict and compensate for temperature effects across the entire operating range, achieving accurate torque measurement without extensive multi-temperature testing.
2Measurement precision
If testing is performed at multiple temperatures to ensure accurate torque measurement, then measurement precision is improved, but manufacturing cost increases
Solution Approach 1:
The patent applies preliminary action by pre-determining the temperature-output relationship through testing at only two reference temperatures. This preliminary testing establishes a mathematical model that can be used for temperature compensation throughout the operating range, significantly reducing the number of expensive multi-temperature tests required during manufacturing while still ensuring accurate torque measurement.
Solution Approach 2:
The patent utilizes parameter changes by creating a mathematical relationship between temperature and output value based on testing at reference temperatures. This model allows the system to predict output values at any temperature without requiring actual testing at each temperature point, thereby reducing manufacturing costs associated with extensive testing while maintaining measurement precision.
3Measurement precision
If a bridge circuit with four detection coils is used to improve measurement sensitivity, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent applies preliminary action by pre-calculating and storing correction values for temperature effects in a lookup table or memory structure. During operation, the system simply retrieves the appropriate correction value based on the measured temperature, avoiding the need for complex real-time calculations while maintaining high measurement precision through accurate temperature compensation.
Solution Approach 2:
The patent utilizes parameter changes by establishing a mathematical model (linear function or polynomial) that describes the relationship between temperature and output value. This model allows the system to compensate for temperature effects through simple mathematical operations or lookup tables, maintaining the high sensitivity provided by the bridge circuit while reducing the computational complexity required for temperature compensation.
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 approach significantly shortens the testing time required for torque sensor manufacturing while maintaining accuracy by using a linear function to correct output values based on temperature changes.
Implementation Method 1
measures torque applied to the rotating shaft by utilizing an inverse magnetostrictive effect that occurs in the rotating shaft when torque is applied to the rotating shaft
Implementation Method 2
measures the torque applied to a rotating shaft by detecting a change in the magnetic permeability of the rotating shaft when torque is applied as a change in inductance of a detection coil
Data Source
AI summary
The method comprises a step of: actually measuring an output values at a first and second reference temperatures for a torque sensor for which a correction value is to be acquired; determining a provisional correction function, which is a linear function showing a relationship between a temperature and the provisional correction values at the first and second reference temperatures, with using the output values at the first and second reference temperatures as the provisional correction values at the first and second reference temperatures; substituting at least one non-reference temperature into the provisional correction function to obtain a provisional correction value at the non-reference temperature, and correcting the provisional correction value at the non-reference temperature by a correction amount at the non-reference temperature obtained in advance, to obtain a correction value at the at least one non-reference temperature.