Magnetoelastic Torque Sensor Rotation Noise Reduction
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Solution Overview
Problem
Existing torque sensing devices suffer from rotation noise due to physical irregularities and variations in magnetic field strength and direction, which affect the accuracy of torque measurement.
Innovation Solution
A method and system for magnetizing a torque transducer that adjusts the magnetization field direction to eliminate rotation noise by measuring magnetic fields, calculating adjustment factors, and forming a final magnetically conditioned region based on these adjustments, using a DC magnetic field source, magnetic field sensors, and a computer-controlled system to ensure precise magnetization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a magnetically conditioned region is formed on the torque sensing element, then torque sensing capability is improved, but rotation noise is generated due to physical irregularities and magnetic field variations
Solution Approach 1:
The patent applies preliminary action by pre-characterizing the magnetic field variations and physical irregularities of the torque sensing element during manufacturing. A map of magnetic field variations is created and stored in memory before the element is installed in the vehicle, allowing the system to compensate for these variations in advance rather than dealing with them during operation.
Solution Approach 2:
The patent implements feedback by using characterizing means (sensors) to measure the actual magnetic field variations and physical irregularities of each torque sensing element. This measured data is fed back to the control system, which then adjusts torque measurements in real-time based on the stored characterization map, eliminating rotation noise through continuous compensation.
2Ease of manufacture
If standard magnetization methods are used, then manufacturing simplicity is maintained, but physical irregularities cause magnetic field variations that produce rotation noise
Solution Approach 1:
The patent applies self-service by having each torque sensing element characterize its own magnetic field variations and physical irregularities through integrated sensors. Each element creates its own compensation map during a self-test procedure, eliminating the need for complex external calibration equipment or manual adjustment procedures during manufacturing.
Solution Approach 2:
The patent implements parameter changes by dynamically adjusting the interpretation of magnetic field data based on the characterized parameters of each specific torque sensing element. The control system modifies measurement parameters and compensation algorithms based on the stored characterization data, allowing standard magnetization methods to produce sufficient results that are then refined through parameter adjustment.
3Reliability
If multiple magnetically conditioned regions are used to improve torque measurement, then measurement reliability is enhanced, but device complexity increases
Solution Approach 1:
The patent applies universality by designing the characterizing means to perform multiple functions: they serve as both sensors for detecting torque during normal operation and as characterization tools for mapping magnetic field variations during manufacturing. This multi-functionality reduces the need for separate calibration equipment and simplifies the overall device structure.
Solution Approach 2:
The patent implements copying by creating a digital map (copy) of the physical irregularities and magnetic field variations of each torque sensing element. This virtual copy is stored in memory and used to compensate for physical imperfections, allowing the system to work around physical limitations without adding complex mechanical or structural components.
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
The solution effectively eliminates rotation noise, enhancing the accuracy of torque measurements by compensating for physical irregularities and ensuring consistent magnetization, resulting in a torque transducer that produces minimal to no rotation noise.
Implementation Method 1
forming a final magnetically conditioned region at the first location on the magnetoelastic element, wherein magnetic fields produced by the final magnetically conditioned region have been adjusted based on the adjustment factors
Implementation Method 2
a ring of magnetoelastically active material disposed around the shaft
Implementation Method 3
the magnetoelastically active region includes one or more magnetically conditioned regions that are magnetically polarized in a circumferential direction and possess sufficient magnetic anisotropy to return the magnetization in the region
Implementation Method 4
Magnetic field sensors mounted proximate to the magnetically conditioned regions, without contacting the regions, are configured to sense only the axial components of magnetic fields produced by the regions
Data Source
AI summary
A system and method for creating one or more magnetically conditioned regions on a rotatable shaft or disk-shaped torque sensing element, wherein rotation noise produced by the element due to magnetic field variations is substantially negated. Upon magnetization of the torque sensing element, rotation noise produced by the magnetically conditioned region is measured. Adjustment factors are calculated based on the measured rotation noise, and the adjustment factors are used to adjust a magnetic field source during subsequent magnetization of the torque sensing element.