Magnetic Position Sensor with Varying Gap Width for Long-Range Accuracy
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Solution Overview
Problem
Existing magnetic position sensors face challenges in measuring long traveling ranges with high accuracy and linearity, while also dealing with mechanical and magnetic errors, and require flexible packaging designs for varying applications.
Innovation Solution
A magnetic position sensor system comprising a track formed by two magnetic rods with a varying gap width, where a magnet moves along a center axis, and one or more magnetic sensors detect the magnetic flux to determine the magnet's position, with optional temperature sensors and an electronic processor for signal processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a magnetic position sensor uses a uniform gap between magnetic rods, then the structure is simple, but measurement accuracy and linearity deteriorate over long traveling ranges
Solution Approach 1:
The patent applies local quality by varying the gap width at different locations along the magnetic rods. The gap is narrower at positions corresponding to longer travel distances and wider at positions corresponding to shorter travel distances. This non-uniform gap distribution compensates for magnetic flux changes over long ranges, maintaining measurement accuracy and linearity without requiring complex external calibration systems.
Solution Approach 2:
The patent changes the geometric parameter of the gap width along the length of the magnetic rods. By progressively varying the gap width parameter from one end to the other, the system optimizes magnetic flux detection across the entire travel range. This parameter change approach enables accurate position measurement over long distances while maintaining a relatively simple rod-based structure.
2Area of stationary object
If the sensor uses a larger gap width, then the device footprint is reduced, but measurement accuracy deteriorates
Solution Approach 1:
The patent implements local quality by making the gap width position-dependent. In regions where the magnet travels longer distances, the gap is narrower to maintain magnetic flux strength and measurement accuracy. In regions with shorter travel distances, the gap is wider to reduce overall device footprint. This spatially varying gap design simultaneously achieves compact dimensions and high measurement precision across the entire range.
3Length of stationary object
If the sensor is designed for long range measurement, then the traveling range is extended, but mechanical and magnetic errors increase
Solution Approach 1:
The patent applies parameter changes by systematically varying the gap width parameter along the length of the magnetic rods to compensate for magnetic flux attenuation over long distances. This pre-calibrated non-uniform gap structure counteracts magnetic errors that would otherwise accumulate over extended ranges, maintaining measurement reliability without requiring complex real-time correction mechanisms.
Solution Approach 2:
The patent implements preliminary action by pre-configuring the non-uniform gap dimensions during manufacturing based on anticipated measurement ranges and error characteristics. This upfront design optimization compensates for expected mechanical and magnetic errors before measurement begins, enabling reliable long-range operation without needing complex real-time error correction systems.
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 system provides improved accuracy, reduced errors, and flexibility in design for measuring both linear and angular positions over long ranges, while accounting for temperature effects on magnetic flux.
Implementation Method 1
one or more magnetic sensors detect the magnetic flux to determine the magnet's position
Data Source
AI summary
A magnetic position sensor comprises a first magnetic rod including a first end and a second end, and a second magnetic rod including a third end and a fourth end, the first end and the third end at a first distance, the second end and the fourth end at a second distance greater than the first distance. The magnetic position sensor further includes a magnet configured to travel relative to the first magnetic rod and the second magnetic rod along a first axis, and one or more magnetic sensors communicatively coupled to the magnet.