Hall-Effect Accelerometer With Nonlinear Flux Concentration
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Solution Overview
Problem
Existing Hall-based accelerometers are complex and lack sufficient sensitivity, requiring multiple devices for different sensitivity levels and facing challenges in cryogenic applications due to electronics incompatibility and noise issues.
Innovation Solution
A Hall-based accelerometer with a rounded magnetic assembly and a Hall sensor, featuring a non-linear magnetic field and moveable components, allows for ultra-high sensitivity and multiple sensitivity levels without additional electronics, using a spring to support the sensor or magnetic assembly for relative displacement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If existing Hall-based accelerometers are used, then they can measure acceleration, but they lack sufficient sensitivity and require multiple devices for different sensitivity levels
Solution Approach 1:
The patent applies parameter changes by utilizing the non-linear relationship between magnetic field strength and position in the gap region. By positioning the Hall sensor within this non-linear field region, small displacements produce large changes in magnetic field strength, thereby achieving ultra-high sensitivity without requiring multiple devices or complex electronics. The conical geometry of the magnetic assembly creates this non-linear field distribution naturally.
Solution Approach 2:
The patent replaces complex electronic systems with a mechanically optimized magnetic field configuration. Instead of using multiple accelerometers with different electronic gain settings to achieve various sensitivity levels, the invention uses a single mechanical structure (conical magnetic assembly) that inherently provides ultra-high sensitivity through its non-linear magnetic field geometry.
2Adaptability or versatility
If existing Hall-based accelerometers are used, then they can operate in various conditions, but they face challenges in cryogenic applications due to electronics incompatibility and noise issues
Solution Approach 1:
The patent extracts the electronic sensing element from the cryogenic environment by positioning the Hall sensor outside the cryogenic chamber. Only the magnetic assembly and proof mass, which have no electronic components, are placed inside the cryogenic environment. This eliminates noise and electronics incompatibility issues while maintaining adaptability for cryogenic applications.
Solution Approach 2:
The patent uses magnetic field interaction as an intermediary between the cryogenic environment and the non-cryogenic Hall sensor. The magnetic field lines extend from the cryogenic chamber through the chamber wall to reach the Hall sensor positioned outside, allowing measurement of cryogenic vibrations without direct electronic contact between the sensor and cryogenic environment.
3Device complexity
If a single accelerometer is used, then device complexity is reduced, but it cannot provide multiple sensitivity levels simultaneously
Solution Approach 1:
The patent achieves multiple sensitivity levels within a single device by exploiting the non-linear magnetic field parameters. The same Hall sensor can operate in different regions of the non-linear magnetic field curve: in the steep non-linear region for ultra-high sensitivity measurements, and in flatter regions for lower sensitivity measurements, thereby providing multiple sensitivity levels without additional devices.
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 provides high sensitivity for low amplitudes and low sensitivity for high amplitudes in a single device, reducing complexity and noise, and is suitable for cryogenic applications without requiring internal electronics, enhancing vibration measurement accuracy.
Implementation Method 1
Accelerometers may use Hall effect sensors to measure accelerations. Movement of the sensors within a magnetic field generates electrical responses that may be measured to determine acceleration.
Implementation Method 2
The rounded first magnetic assembly comprises a first concentrator extending from a first end having a first magnet to an opposing second end having a second magnet and forming a first gap between the first and second ends. The first magnetic assembly has a reduced width at each of the first and second ends and produces a non-linear first magnetic field between the first and second ends.
Data Source
AI summary
Accelerometer with Hall effect sensor. The accelerometer may have a rounded magnetic assembly with rounded flux concentrator, such as a C-shape or horseshoe. Opposing ends of the concentrator may each have a magnet and form a gap having a highly-concentrated, non-linear magnetic field. Opposing ends of the concentrator may have a reduced width, such as cone-shaped. A Hall sensor may be located within or near the gap. The sensor or magnet may be moveably supported by a spring. The sensor may move perpendicularly relative to a direction of the magnetic field lines. A second magnet may be included, for example adjacent the gap, to provide a second set of magnetic field lines with shallower gradient for lower sensitivity. Movement of the sensor within the two magnetic fields may provide multiple wide-ranging sensitivities, such as “X” V/g as well as X/500 mV/g or X/5,000 mV/g.