Microactuator Positioning Using Dual Hall Sensors
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Solution Overview
Problem
Magnetic field sensors face significant challenges in achieving high resolution and precision measurements, particularly at microscopic scales, due to exponential degradation of position sensor resolution with distance and interference from noise, which limits their application in micro- and nanotechnologies that require complex and expensive equipment.
Innovation Solution
A microtechnical device with a permanent magnet and two Hall effect sensors positioned to detect magnetic field variations along perpendicular axes, allowing for two-dimensional measurements with enhanced sensitivity and noise filtering, utilizing a digital control tool for accurate position data conversion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If magnetic field sensors are used to measure position, then measurement capability is provided, but position resolution degrades exponentially with distance and noise increases
Solution Approach 1:
The patent transitions from single-degree-of-freedom linear/rotary sensors to a two-dimensional measurement system using two Hall effect sensors positioned at different locations and orientations. This dimensional expansion allows simultaneous measurement of both linear and angular displacements, achieving high resolution without requiring the sensor to be extremely close to the magnet.
Solution Approach 2:
The patent optimizes the measurement by changing multiple parameters simultaneously: sensor positions are strategically placed in the main plane of symmetry at specific working distances, sensor orientations are aligned perpendicular to magnetization direction, and the system operates at extremum points where gradient components are maximum. This multi-parameter optimization maintains high resolution at practical distances.
2Measurement precision
If industrial magnetic field applications operate in macroscopic domain, then measurement capability is provided, but complex and expensive equipment is required to increase resolution and filter noise
Solution Approach 1:
The patent combines two Hall effect sensors into a single integrated measurement system that simultaneously provides both linear displacement and angular orientation information. This merging eliminates the need for separate linear and rotary sensors, reducing system complexity and cost while maintaining high measurement precision.
Solution Approach 2:
The system uses the magnetic field's own spatial variations and gradient extremum points as natural measurement references. By positioning sensors at locations where gradient components are maximum and using the field's symmetry properties, the system achieves high resolution without requiring external calibration equipment or complex noise filtering systems.
3Device complexity
If single degree of freedom displacement measurement is used, then simplicity is maintained, but two-dimensional positioning capability is lost
Solution Approach 1:
The patent creates a universal measurement system where two Hall effect sensors positioned in the main plane of symmetry can simultaneously measure both linear displacement along the magnetization axis and angular rotation perpendicular to it. This multi-functional approach allows the same sensor configuration to provide comprehensive two-dimensional positioning information.
Solution Approach 2:
The system expands from one-dimensional linear measurement to two-dimensional measurement by adding angular sensitivity through the second sensor oriented perpendicular to the first. This dimensional expansion enables simultaneous measurement of both translational and rotational displacements without significantly increasing system complexity.
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 device achieves improved position measurement precision and reduced noise interference, enabling high-resolution magnetic field sensing suitable for micro- and nanotechnological applications without the need for bulky external equipment.
Implementation Method 1
Known sensors for this purpose are Hall effect sensors. A position sensor using the measurement of the magnetic field of a permanent magnet by a magnetic field sensor sees its position resolution degrade exponentially as a function of the distance between the magnet and the magnetic sensor.
Data Source
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Figure 2A~3
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AI summary
The present invention relates to a microtechnique device, comprising an actuator, designed to move movable equipment with a permanent magnet with respect to a support. The actuator is designed to move the movable equipment in two degrees of freedom from a position of rest, and the permanent magnet is chosen to have a magnetic field distribution that presents a main plane of symmetry and a main direction of magnetization passing through a centre. The device comprises a first magnetic sensor and a second magnetic sensor, these two being designed to detect a movement of the magnet. The sensors are positioned with respect to the position of rest of the magnet in a specific manner in the main plane of symmetry of the magnetic field and near to extrema. The first and second sensors are then sensitive to the movements of the movable equipment perpendicular to their respective working axes.