Inductive Displacement Sensor Signal Processing
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Solution Overview
Problem
Inductive displacement sensors in industrial applications, such as aircraft, require an excitation voltage that is often transmitted via cables, increasing system mass and complexity while reducing reliability due to the need for separate electrical generation and processing circuits.
Innovation Solution
A method that eliminates the need for an excitation voltage by digitizing and processing measurement voltages from secondary windings, using cross-vector components and low-pass filtering to estimate displacement, thereby reducing system mass and increasing reliability by eliminating the need for cable transmission of the excitation voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an excitation voltage is transmitted via cable from a separate electrical generation circuit to the electrical processing circuit, then the inductive displacement sensor can function, but the system mass increases and reliability decreases
Solution Approach 1:
The patent merges the electrical generation circuit and electrical processing circuit into a single integrated unit, eliminating the need for cable transmission of excitation voltage. This consolidation removes the cable mass and connection points, directly reducing system mass while improving reliability by eliminating potential failure points in the cable connection system.
Solution Approach 2:
The patent extracts and eliminates the cable transmission component from the system architecture. By removing the cable that transmits excitation voltage between separate circuits, the system achieves mass reduction and improved reliability without compromising sensor functionality.
2Device complexity
If synchronous demodulation is implemented using excitation voltage from a separate circuit, then displacement estimation can be performed, but device complexity increases due to cable requirements
Solution Approach 1:
The patent combines the electrical generation and processing functions into one integrated circuit, eliminating the cable infrastructure. This merger simplifies the overall device architecture by removing external connection requirements while maintaining the capability to perform displacement estimation through integrated signal processing.
3Weight of moving object
If a cable connects the electrical generation circuit and electrical processing circuit, then excitation voltage can be transmitted, but the system requires more components increasing mass and complexity
Solution Approach 1:
The patent removes the cable component entirely from the system by integrating the electrical generation and processing circuits. This extraction eliminates the need for cable transmission, directly reducing system mass and simplifying the device architecture by removing connection points and cable management requirements.
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 method achieves accurate displacement measurement without the excitation voltage, reducing system mass and complexity while maintaining measurement accuracy, although it is limited to a specific angular range due to ambiguity in angle measurement outside [-π/2, π/2].
Implementation Method 1
An excitation voltage is applied to the terminals of the primary winding. A first measurement voltage is generated at the terminals of the first secondary winding and a second measurement voltage is generated at the terminals of the second secondary winding.
Implementation Method 2
applying the cross vector as input to a low-pass filter to obtain a filtered vector
Data Source
Figure 1
Figure 2~3
Figure 4
AI summary
The invention relates to a method for measuring a displacement, comprising the steps of: - acquiring and digitising a first measurement voltage (Va) at the terminals of a first secondary winding and a second measurement voltage (Vb) at the terminals of a second secondary winding of an inductive displacement transducer; - multiplying the first measurement voltage by itself in order to obtain a first component (Vi) of a crossed vector (Vc), multiplying the second measurement voltage by itself in order to obtain a second component (V2) of the crossed vector (Vc), multiplying the first measurement voltage by the second measurement voltage in order to obtain a third component (V3) of the crossed vector (Ve); - applying the crossed vector to the input of a low-pass filter in order to obtain a filtered vector (Vf); and - estimating the displacement from the components of the filtered vector (Vf).