Magnetoelastic Torque Sensor Temperature Compensation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Torque sensors in vehicular systems, such as electronic power-assisted steering, face challenges due to thermal errors caused by heat radiation, leading to increased costs and reduced accuracy, as they require additional components like thermistors and switches to account for temperature measurements, which negatively impact continuous torque measurement.
Innovation Solution
A magneto-elastic torque sensor assembly with a shaft generating a magnetic field in response to applied torque, utilizing a pair of sensing coils and a controller to sense temperature differences and generate output signals that account for these variations, enabling continuous torque measurement while compensating for thermal errors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If additional thermistors and switches are added to measure temperature and compensate thermal errors, then temperature compensation capability is improved, but device complexity and cost increase
Solution Approach 1:
The sensing coils serve dual purposes: they function as both torque sensing elements and temperature sensing elements. By measuring the resistance of these existing coils, the system obtains temperature information without requiring separate thermistors, thus achieving multi-functionality and reducing device complexity
Solution Approach 2:
The sensing coils themselves provide the temperature measurement function through their resistance characteristics. The system uses the inherent electrical properties of the existing torque sensing components to self-determine temperature, eliminating the need for external temperature sensing components
2Measurement precision
If additional thermistors and switches are added to measure temperature and compensate thermal errors, then temperature compensation capability is improved, but manufacturing cost increases
Solution Approach 1:
The sensing coils serve dual purposes: they function as both torque sensing elements and temperature sensing elements. By measuring the resistance of these existing coils, the system obtains temperature information without requiring separate thermistors, thus achieving multi-functionality and reducing device complexity
Solution Approach 2:
The sensing coils themselves provide the temperature measurement function through their resistance characteristics. The system uses the inherent electrical properties of the existing torque sensing components to self-determine temperature, eliminating the need for external temperature sensing components
3Measurement precision
If a switch is added to change modes between torque and temperature measurement, then temperature measurement capability is improved, but continuous torque measurement is disrupted
Solution Approach 1:
The system continuously measures torque through the sensing coils while simultaneously obtaining temperature data by measuring the resistance of the same coils. This dual measurement occurs without interrupting the torque sensing function, maintaining continuous useful action for both measurement types
Solution Approach 2:
The sensing coils serve dual purposes: they function as both torque sensing elements and temperature sensing elements. By measuring the resistance of these existing coils, the system obtains temperature information without requiring separate thermistors, thus achieving multi-functionality and reducing device complexity
4Adaptability or versatility
If the sensor operates in high temperature environment, then adaptability to vehicular systems is improved, but thermal errors increase
Solution Approach 1:
The system continuously monitors the resistance of the sensing coils to obtain real-time temperature feedback. This temperature information is then used to compensate for thermal errors in the torque measurement, creating a closed-loop feedback mechanism that maintains measurement precision in high temperature environments
Solution Approach 2:
The system measures changes in electrical resistance of the sensing coils as a function of temperature. By detecting these parameter changes and using them to compensate for thermal effects, the system maintains measurement accuracy across varying temperature conditions
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 a low-cost, high-precision torque sensor that continuously measures torque without the negative impact of thermal errors, maintaining accuracy by accounting for temperature differences in the sensing coils, thus enhancing the performance of vehicular systems.
Implementation Method 1
a shaft configured to receive an applied torque and comprising at least one region being magneto-elastic and being configured to generate a magnetic field in response to the applied torque
Implementation Method 2
a first pair of sensing coils disposed adjacent to the region and being configured to sense the magnetic field
Data Source
AI summary
A torque sensor assembly comprises a shaft configured to receive an applied torque. The shaft comprises at least one region, which is magneto-elastic and configured to generate a magnetic field in response to the applied torque. A pair of sensing coils disposed adjacent to the region is configured to sense the magnetic field. One or more sensors sense a temperature of each of the sensing coils. A controller is coupled to the pair of sensing coils and the sensor(s). The controller is configured to receive the sensed temperature of each of the sensing coils, determine a temperature difference between the sensing coils and generate an output signal based on the sensed magnetic field. The output signal accounts for the temperature difference between the sensing coils.