Stroke Sensor Sine Flux Density Temperature Compensation
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Solution Overview
Problem
Conventional stroke sensors and rotation angle sensors face limitations in accuracy due to temperature-induced fluctuations in magnetic flux and electric outputs, leading to non-ideal linear characteristics and increased sensing errors, especially when magnets rotate or are displaced linearly.
Innovation Solution
The stroke sensor employs two magnetism-sensitive sections with magnetism-sensitive surfaces in the same direction, arranged to form a sine curve correlation with magnetic flux density, allowing for temperature characteristic cancellation through sum and difference calculations, and inverse trigonometric processing to achieve ideal linear characteristics, while additional magnetism-sensitive sections with different orientations enhance robustness and accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single magnetism sensitive section is used to sense magnetic flux, then the device structure is simple, but temperature fluctuations cause sensing errors and non-ideal linear characteristics
Solution Approach 1:
The patent divides the sensing function into multiple magnetism sensitive sections (at least two) arranged at different positions. Each section senses magnetic flux independently, and their outputs are processed through sum and difference calculations to eliminate temperature-induced errors while maintaining measurement accuracy.
Solution Approach 2:
The patent implements a feedback mechanism where the outputs from multiple magnetism sensitive sections are continuously monitored and processed. By calculating sum and difference values and applying inverse trigonometric functions, the system compensates for temperature fluctuations in real-time, ensuring accurate stroke amount detection.
2Measurement precision
If multiple magnetism sensitive sections are used to cancel temperature characteristics, then sensing accuracy improves, but device complexity increases
Solution Approach 1:
The patent uses multiple magnetism sensitive sections arranged at specific positions to detect magnetic flux. By segmenting the sensing function across multiple sections and processing their outputs through mathematical operations (sum and difference), the system achieves temperature compensation without requiring complex additional hardware.
Solution Approach 2:
The patent changes the operational parameters by using mathematical transformations (sum and difference calculations, inverse trigonometric functions) on the electrical outputs from multiple magnetism sensitive sections. This allows temperature characteristic cancellation through parameter processing rather than physical structural complexity.
3Adaptability or versatility
If the magnet is displaced linearly while rotating, then the sensor can measure both stroke and rotation, but magnetic flux density fluctuates causing increased sensing errors
Solution Approach 1:
The patent segments the sensing function into multiple magnetism sensitive sections positioned to detect magnetic flux from the magnet during both linear displacement and rotation. This segmentation allows the system to distinguish between stroke-related flux changes and rotation-related flux changes, enabling accurate measurement of both parameters simultaneously.
Solution Approach 2:
The patent uses feedback processing where the outputs from multiple magnetism sensitive sections are continuously analyzed. By calculating sum and difference values and applying inverse trigonometric functions, the system compensates for flux density fluctuations caused by magnet rotation, ensuring accurate stroke amount detection even during combined motion.
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 approach enables highly accurate output values for stroke amount and rotation angle, even with temperature fluctuations, reducing sensing errors and improving accuracy and mountability while reducing costs.
Implementation Method 1
two magnetism sensitive sections arranged parallel to the longitudinal direction for sensing a magnetic flux formed by the magnet and for outputting electric outputs respectively
Data Source
AI summary
A stroke sensor has two magnets, which are magnetized in a cross-section direction and are displaced in a longitudinal direction, and two magnetism sensitive sections arranged parallel to the longitudinal direction. The magnets have circular-arc-shaped swelling end edges respectively and are magnetized such that the swelling end edges have opposite polarities. Thus, a distribution of a magnetic flux density on an arrangement axis substantially coincides with a sine curve. The magnetic flux having such the distribution is displaced in the longitudinal direction together with the magnets. The magnetism sensitive sections are arranged on the arrangement axis to be distant from each other by a distance of one fourth of a cycle of the sine curve. Thus, the stroke sensor that is not affected by temperature and that has high sensing accuracy can be provided.