Inductive Position Sensor with Staggered Coils for Humid Environments
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Electronic digital display calipers using capacitive position sensors face reading errors in humid or oily environments, and existing inductive position sensors with single-channel magnetic field generators have limitations in dual-channel drive applications, affecting measurement accuracy and scope of use.
Innovation Solution
An inductive position measuring sensor with a dual-channel drive electromagnetic induction measurement circuit, featuring staggered arrangement of driving and induction coils, and conductive loops with specific winding directions and intervals to reduce coupling interference and enhance measurement accuracy in humid and oily environments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If capacitive position sensor is used in electronic digital display caliper, then measurement accuracy is improved, but reliability deteriorates in humid or oily environments
Solution Approach 1:
The patent replaces the capacitive position sensor (which is sensitive to environmental factors) with an inductive position sensor that uses electromagnetic induction. The inductive sensor generates magnetic fields that are not affected by humidity or oil, thereby maintaining measurement accuracy while improving reliability in challenging environments.
Solution Approach 2:
The patent changes the operating principle from capacitive sensing to inductive sensing, fundamentally altering the physical parameter used for measurement. By using magnetic field induction instead of electric field capacitance, the sensor becomes immune to environmental interference from humidity and oil while preserving measurement precision.
2Device complexity
If single-channel magnetic field generator is used, then device complexity is reduced, but adaptability deteriorates for dual-channel drive applications
Solution Approach 1:
The patent divides the magnetic field generation system into multiple independent channels (dual-channel drive) with separate excitation coils. Each channel can operate independently, allowing the sensor to adapt to different measurement requirements while maintaining a relatively simple overall structure. The segmented approach enables versatility without proportionally increasing complexity.
Solution Approach 2:
The patent designs the inductive position sensor with dual-channel drive capability that can function in both single-channel and dual-channel modes. This universal design allows the same sensor structure to adapt to different application requirements, whether simple single-channel measurements or complex dual-channel measurements, without requiring different hardware configurations.
3Device complexity
If magnetic field generator and magnetic flux sensor are placed at the same position, then device complexity is reduced, but measurement precision deteriorates due to direct coupling interference
Solution Approach 1:
The patent extracts the excitation coil and measurement coil into spatially separated positions. The excitation coil generates the magnetic field at one location while the measurement coil detects the magnetic flux at a different location. This separation removes the direct coupling interference that would occur if both coils were at the same position, thereby improving measurement accuracy while maintaining reasonable structural simplicity.
Solution Approach 2:
The patent introduces the magnetic field as an intermediary between the excitation coil and measurement coil. The excitation coil generates magnetic field lines that pass through the measurement area and are detected by the measurement coil. This intermediary approach allows the system to maintain spatial separation between coils while ensuring effective magnetic coupling for accurate measurement.
4Measurement precision
If number of drive channels is increased to improve measurement points, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent implements dynamic multiplexing of the dual-channel drive system, where the excitation coils can be selectively activated in different sequences and combinations. This dynamic control allows the system to achieve multiple measurement points and high measurement accuracy by temporally separating the excitation of different coils, rather than requiring all coils to operate simultaneously, thereby avoiding proportional increases in circuit complexity.
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 sensor effectively reduces direct coupling signals and increases indirect coupling signals, improving measurement accuracy and enabling reliable operation in challenging environments while maintaining a simple structure and low manufacturing costs.
Implementation Method 1
excitation signals are generated by the two sets of driving coils, and received by the induction coils of the sliding ruler through introduction with the coupling coils on the fixed ruler
Implementation Method 2
the output signal generated by each magnetic flux sensitive element is insensitive to the magnetic flux generated by the magnetic field generator, through the way that the spatial magnetic fields mutually offset in the same magnetic flux sensitive element
Data Source
AI summary
An inductive position measuring sensor comprises a fixed ruler and a sliding ruler which can move relatively along the direction of the measuring axis. A series of coupling coils are made on the fixed ruler in the measuring direction,-two sets of driving coils are disposed on the sliding ruler, and induction coils in a staggered manner are also disposed on the sliding ruler. The two sets of driving coils generate excitation signals, by interaction with the coupling coils on the fixed ruler, and being received by the induction coils of the sliding ruler, they are used for measuring the relative movement of the fixed ruler and the sliding ruler. By controlling the positions and winding directions of the driving coils and the induction coils, the sensor can effectively inhibit the direct space signal interference of the driving coils to the induction coils, and the signal-to-noise ratio is improved.