Accurate Coupling Coefficient Model for Eddy Current Sensor Displacement Calculation

Eddy current displacement sensors, recognized for their capabilities of excellent anti-interference capabilities and high-frequency response, are used in the industrial and aerospace sectors. Inherently nonlinear in their large-range displacement measurements, these sensors traditionally require a series of correction curves for accurate measurement. This approach largely stems from the lack of a mathematical model capable of accurately describing the nonlinear behavior. This article introduces a method that involves precisely establishing a mathematical model of the mutual inductance coefficients between the probe of the eddy current displacement sensor and the detection target, thereby effectively calculating the gap between them. The model is applicable to probe coils of various structures and detection targets made of different materials, greatly simplifying the nonlinear correction process. Experimental validation demonstrates the effectiveness of this method for probe coils of different structures or detection targets made of varying materials, with a maximum nonlinearity of less than 1%, confirming its efficiency and accuracy in practical applications.