Inductive Sensor Eddy Current Field Shaping
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Solution Overview
Problem
Conventional inductive position sensors face challenges in achieving linearity and offset correction due to mechanical constraints and limited space, requiring additional board space for offset coils or expensive software solutions.
Innovation Solution
Incorporating eddy current generating materials, such as aluminum, strategically positioned around the sensing coils to interfere with wire-to-wire communication and modify the output shape of the sensor, thereby improving linearity and offset without the need for external coils or software modifications.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If offset coils are added to correct linearity and offset, then measurement precision is improved, but device complexity and board space requirements increase
Solution Approach 1:
The patent extracts the offset correction function from separate offset coils and integrates it into the existing sensing coil structure. By modifying the sensing coil geometry (adding segments, changing winding patterns) rather than adding separate correction coils, the patent eliminates the need for additional hardware while maintaining linearity and offset correction capabilities
Solution Approach 2:
The sensing coil is designed to perform multiple functions simultaneously: position detection and offset correction. By configuring the sensing coil with specific geometric modifications (such as adding segments or changing winding patterns), the same coil structure that detects position also provides the field shaping needed for offset and linearity correction, eliminating the need for separate correction coils
2Measurement precision
If software solutions are used to correct offset and linearity, then measurement precision is improved, but cost increases
Solution Approach 1:
The patent replaces software-based correction with a hardware-based geometric solution. Instead of using expensive microprocessors and software algorithms to calculate and correct non-linearity, the patent uses carefully designed coil geometries (segmented coils, modified winding patterns) that inherently produce linear transfer curves, thereby eliminating the need for expensive software correction
3Measurement precision
If the air gap is reduced to improve sensitivity, then measurement precision is improved, but reliability decreases due to increased susceptibility to interference
Solution Approach 1:
The patent applies different geometric configurations to different parts of the sensing coil system. By segmenting the coils and applying specific winding patterns to different sections, the patent creates localized field distributions that enhance sensitivity in the measurement region while providing inherent shielding against interference, allowing small air gaps without compromising reliability
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 effectively corrects linearity and offset issues in inductive position sensors by altering the transfer curve, enhancing accuracy and reducing costs associated with software solutions or additional board space requirements.
Implementation Method 1
Eddy current generating material is associated with any of the coils so as to provide an eddy current that interferes with wire to wire communication between the sensing coils and the source coil
Implementation Method 2
inductive position sensor includes a source coil 12, a first sensing coil 14, a second sensing coil 16 and a moving target 18
Data Source
AI summary
An inductive position sensor determines a position of an object. The sensor incudes a circuit board, a wire source coil constructed and arranged to provide a certain operating frequency, a first wire sensing coil, and a second wire sensing coil. The source coil, and first and second sensing coils are embedded in the circuit board, and each of the first and second sensing coils are constructed and arranged to provide an output as the object passes by source coil and the first and second sensing coils. Eddy current generating material is associated with any of the coils so as to provide an eddy current that interferes with wire to wire communication between the sensing coils and the source coil, so as to alter the output of the sensing coils to improve accuracy of the sensor to shape the output.