Inductive Position Detection With Z-Height Compensation
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Solution Overview
Problem
Existing position sensing systems face challenges in accurately localizing movement of conductive objects in three-dimensional space due to sensitivity to mechanical tolerances, substrate vibrations, and thermal changes, which affects the accuracy of position detection.
Innovation Solution
A position detecting system that uses inductive sensors with a z-height sensor to enhance measurement accuracy by compensating for changes in height and mechanical tolerances, allowing for robust and accurate position sensing across a two-dimensional plane by measuring the relative distance between the sensor and the target, and using a position processor to determine the target's position based on changes in coil characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional inductive sensors are used for position detection, then the system structure is simple, but the measurement accuracy deteriorates due to sensitivity to mechanical tolerances, substrate vibrations, and thermal changes
Solution Approach 1:
The patent transitions from two-dimensional position detection to three-dimensional detection by adding height measurement capability. A second sensor detects height variations from the plane, compensating for mechanical tolerances and vibrations that affect conventional 2D sensors. This dimensional addition resolves the accuracy problem without requiring complex mechanical tolerance control.
Solution Approach 2:
The patent introduces a second height-detecting sensor as an intermediary measurement device. This sensor measures vertical displacements and provides compensatory data that corrects position detection errors caused by mechanical tolerances and thermal expansion, thereby improving overall measurement accuracy without directly modifying the primary position sensor.
2Measurement precision
If mechanical tolerances are tightly controlled to improve position detection accuracy, then measurement precision improves, but manufacturing cost and complexity increase
Solution Approach 1:
The patent replaces mechanical tolerance control with electromagnetic sensing. Instead of relying on precisely machined mechanical components, the system uses inductive sensors to detect position and a second sensor to detect height variations. This substitution eliminates the need for tight mechanical tolerances while maintaining or improving measurement accuracy.
Solution Approach 2:
The patent changes the measurement parameters from purely lateral position to include vertical height detection. By measuring the height parameter and using it to compensate for positional errors, the system achieves accurate position detection without requiring precise mechanical tolerances in the lateral dimensions.
3Measurement precision
If the distance between the coil and target is reduced to improve sensitivity, then measurement sensitivity improves, but the system becomes more sensitive to mechanical tolerances and vibrations
Solution Approach 1:
The patent implements feedback by using the second height-detecting sensor to monitor vertical position changes and compensating for these changes in the position detection algorithm. This feedback mechanism allows the system to maintain high sensitivity with reduced coil-to-target distance while compensating for vibrations and mechanical variations that occur at closer distances.
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 achieves improved accuracy and reduced dependency on mechanical tolerances, enabling precise position detection with reduced complexity and closer distances between the coil and target, while maintaining robustness against variations in mechanical tolerances and thermal changes.
Implementation Method 1
movement of a conductive object through the magnetic field generated by a coil causes variations in the magnetic field that are detected by the sensors
Data Source
AI summary
A position detecting system detects and responds to the movement of a target through a sensing domain area of a plane. The movement causes the amount of the target that lies within a first sensing domain area of a first sensor to change. A second sensor detects a height from the plane to a sensor for enhancing accuracy of measurements from the first sensor.