Inductive Position Sensor Offset Compensation
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Solution Overview
Problem
Existing inductive position sensors using eddy current coupling face measurement offset issues due to asymmetrical secondary windings, leading to reduced measurement range or increased sensor size, which are not effectively compensated by previous solutions.
Innovation Solution
The proposed inductive position sensor incorporates a balancing system with secondary windings having offset tracks and modulated shapes to compensate for measurement offset, ensuring accurate position determination across the entire measurement range without increasing sensor size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the secondary windings are made asymmetrical to match the primary winding configuration, then the sensor can be compact, but measurement offset signals appear
Solution Approach 1:
The patent applies asymmetry principle by intentionally creating asymmetrical secondary windings that mirror the asymmetrical primary winding configuration. This asymmetry is designed to compensate for the measurement offset signals that would otherwise appear, allowing the sensor to maintain compact size while achieving accurate measurements across the full range.
2Measurement precision
If the sensor size is increased to compensate for measurement offset, then measurement accuracy improves, but the sensor becomes larger
Solution Approach 1:
The patent applies local quality principle by modifying only the specific portions of the secondary windings that interact with the end segments of the primary winding. Instead of changing the entire sensor structure, the invention locally adjusts the winding configurations in the critical end regions to compensate for measurement offset, thereby maintaining compact overall sensor size while improving measurement accuracy.
3Length of moving object
If the measurement range is extended by increasing sensor size, then more measurement range is available, but the sensor size increases
Solution Approach 1:
The patent applies parameter changes principle by modifying the geometric parameters of the secondary windings, specifically their positions and configurations relative to the primary winding's end segments. By optimizing these parameters, the sensor achieves extended measurement range without increasing overall sensor size, as the winding parameters are adjusted to maximize measurement capability within the existing compact structure.
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 solution effectively reduces measurement offset while maintaining the measurement range, providing precise position determination for both linear and angular trajectories without the need for increased sensor size.
Implementation Method 1
a primary winding (7) surrounding only two secondary windings (8, 9) magnetically coupled to the primary winding (7)... The magnetic field thus created is perceived by the secondary windings and induces a current in said secondary windings
Implementation Method 2
The target (3) is made of a conductive material to allow the flow of eddy currents
Implementation Method 3
The inductive coupling between the primary winding and the secondary windings is modulated by the position of the target
Data Source
Figure 1
Figure 3~4
Figure 5
AI summary
The invention relates to an inductive position sensor for determining the position of a moving object along a linear or rotary trajectory (F), comprising: - a mobile target (3) designed to modify an electromagnetic field; - a fixed circuit board (5) extending along a limited portion and comprising a primary winding (7) surrounding two secondary windings (8, 9) having substantially identical lengths (L) and in the shape of sine and cosine functions; - a current generator (11) for creating inductive coupling that is modulated by the position of the target; - a detector (13) for detecting the linear or angular position of the target; - and a system for balancing the coupling between the primary winding (7) and the secondary windings (8, 9) in order to compensate the measurement offset induced by the proximity between the secondary windings (8, 9) and the end segments (7b) of the primary winding (7).