Experimental and finite element analysis of coil position effects in inductive sensors using a design of experiments approach

Planar coils offer advantages such as a two-dimensional structure and compact design, making them suitable for various applications. They are widely used in position sensing, proximity detection, and non-contact measurement. Planar coils rely on mutual inductance as a key parameter. The mutual inductance changes with the relative displacement between two coils. The mutual inductance variation is the basis of inductive sensors. This study includes both experimental and finite element investigations of the effect of coil displacement on mutual inductance. In the experimental setup, a special fixture was designed to enable the movement of one coil with six degrees of freedom, allowing precise control of both axial and angular displacements. First, the accuracy of the finite element model was validated by comparing its results with those from a reference study, yielding an R 2 score between 0.9377 and 0.9721. The mutual inductance between two coils was evaluated under different conditions using both methods. The Taguchi method was employed to reduce the number while maintaining accuracy. The signal-to-noise ratio analysis showed that minimizing the vertical gap between the coils enhances magnetic coupling, while x-axis rotation has the least effect. • Mutual inductance variations in planar coils under displacement are investigated. • A fixture enabling six degrees of freedom for axial and angular motion is designed. • The finite element simulation is validated with reference data, achieving R 2 scores between 0.9377 and 0.9721. • Mutual inductance in air and a steel plate is evaluated to analyze medium effects. • Experimental and simulation results agree with each other, yielding R 2 scores between 0.9994 and 0.9999.