Linear Synthesis of Uniform Anaxial Eddy Current Probes with a Volumetric Structure of the Excitation System

Abstract

The problem of multiparameter linear synthesis of moving surface eddy current probes with a volumetric structure of the excitation system, characterized by uniform sensitivity in the testing zone, is solved. For research, an anaxial design was selected. It ensures the location of the measuring coil at the place of maximum concentration of eddy currents with their uniform distribution. The task was implemented using metaheuristic optimization algorithms for searching of a global extremum. They are a hybrid algorithm based on the genetic one with local search using the Nelder-Mead simplex method, a low-level hybrid of the particles swarm algorithm with a strategy of the randomly dynamically variable topology of connections with the genetic one, which ensures the evolutionary formation of the swarm composition. Preliminary the construction of the metamodel of the probe using a composite of artificial neural networks, namely RBF-neural networks was carried out. In order to improve the accuracy of constructing the metamodel, the search area is represented by a set of "stitched" several sub-areas, separated by the radius of the excitation coils and the height of their location above the testing object. The objective function in the synthesis problem was formulated as a quadratic functional. The results of the obtained solution are presented in the form of the eddy current density distribution with an indication of the obtained width of the testing zone, where this distribution is close to uniform