Optimization of Eddy Current Sensor for Proximity and Deformation Detection

Electromagnetic induction and eddy current inspection are significant methods for the non-destructive testing and measurements of material electrical and magnetic properties. This work presents an approach for applying such methods in the detection of objects position in the three-dimensional space with a small range (1 to 40 mm) and (1 to 10°).
The detection resolution for two systems was investigated in this work. The first system is based on the electromagnetic induction between circular air coils (ICC). The proximity between the coils and their basic attributes were varied to track their influence on the detection resolution. In the second system, the eddy currents were induced in a circular plate of a non-magnetic material. The distance of this plate to the coils and its orientation were varied and the effect from eddy currents on a secondary coil was studied.
An analytical solution was used to set the geometry parameters of the used coils according to specific selected inductances. In the next step, a time-dependent simulation study was carried out for each system and its results were compared to those gained from experiments. The results from experiments and simulations showed the different range of sensitivity according to distance between coils and tilt-angles. Finally, the simulation is used to optimize a system in order to gain better sensitivity or detection resolution.
In conclusion, the presented systems represent a candidate for a proximity and deformation detection sensor. This sensor can be installed in multiple fields in the industry such as, robots, manipulators, milling and drilling machines. Further investigations are however essential to ensure a stabile detection possibility in several spatial directions and to improve the sensitivity by using other coil/material types.