Inductive Linear Displacement Sensor Calibration Coil
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Solution Overview
Problem
Inductive linear displacement sensors require complex calibration procedures that are sensitive to various parameters, making unambiguous zero position detection challenging and prone to errors.
Innovation Solution
Incorporating a calibration coil inductively coupled to the primary coil, designed to produce a signal with a single zero crossing at the center, allowing for simple and unambiguous calibration independent of secondary coil signal evaluation, and enabling easy recalibration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a calibration coil with a single zero crossing is introduced, then calibration precision and unambiguity are improved, but device complexity increases due to the additional coil component
Solution Approach 1:
The calibration coil acts as an intermediary element that provides a distinct zero-crossing signal to mark the center position. This separate calibration coil mediates between the primary coil and the measurement system, enabling unambiguous zero position detection without interfering with the normal measurement function of the secondary coils.
Solution Approach 2:
The calibration coil performs a preliminary function by establishing the zero position reference before actual measurements begin. The single zero-crossing signal is generated in advance to define the center of the measuring range, allowing subsequent measurements to be accurately referenced to this predetermined position.
2Reliability
If traditional calibration methods using secondary coil signals are used, then device structure remains simple, but calibration reliability deteriorates due to sensitivity to various parameters
Solution Approach 1:
The calibration function is extracted from the measurement function by introducing a dedicated calibration coil. This separates the calibration task from the secondary coils used for measurement, eliminating the interference and parameter sensitivity that occur when trying to use measurement coils for calibration purposes.
Solution Approach 2:
The sensor system is segmented into distinct functional components: the primary coil for generating the magnetic field, secondary coils for measurement, and a separate calibration coil for zero position detection. This segmentation allows each component to perform its specific function optimally without interfering with others.
3Measurement precision
If the sensor size is increased to accommodate additional calibration components, then calibration capability is improved, but the compact sensor design is compromised
Solution Approach 1:
The calibration coil is merged with the existing coil structure in the planar arrangement. By using the same planar space and magnetic field generation approach as the primary and secondary coils, the calibration coil integrates seamlessly into the existing design without requiring additional volume or significantly increasing the sensor footprint.
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
Enables precise and unambiguous calibration of the sensor's zero position, reducing the need for complex control electronics and providing an additional diagnostics option, ensuring reliable operation and easy recalibration.
Implementation Method 1
the linear displacement sensor has a calibration coil, which is inductively coupled to the primary coil
Implementation Method 2
the secondary coils are inductively coupled to the primary coil
Data Source
AI summary
The disclosure relates to an inductive linear displacement sensor that includes a primary coil and two secondary coils inductively coupled to the primary coil. The linear displacement sensor has a calibration coil inductively coupled to the primary coil. The calibration coil is arranged such that a signal produced by the calibration coil has only one zero crossing at the center of the linear displacement sensor.