Research On Submarine Degaussing Current Optimization Based On Improved Differential Evolution Algorithm

The induced magnetic field generated by a magnetized submarine can alter the distribution of the original geomagnetic field,resulting in a magnetic anomaly signal in the area where the submarine is located.This magnetic anomaly signal can be located by equipment such as aeromagnetic detectors with magnetic anomaly detection technology,posing a threat to the submarine’s own safety.Therefore,it is of great significance to study the magnetic field of the submarine and the demagnetization method.Generally,the magnetic field generated by the degaussing winding coil is compensated for by the magnetic field induced in the submarine by controlling the current level of the degaussing winding through the degaussing system.This thesis researches on the optimization of submarine degaussing currents based on an improved differential evolutionary algorithm,and the main work done is as follows.This thesis proposes a differential evolution algorithm based on dynamic twin populations,whose main improvement strategy is to improve the search accuracy and convergence speed of the algorithm by introducing a central variation scheme and dynamic twin populations.Finally,the performance of the improved differential evolution algorithm is tested by three different test functions,and the simulation results show that the performance of the improved algorithm has been greatly improved.In this thesis,an ellipsoidal magnetic monopole array modelling method is proposed according to the arrangement of the submarine’s own ferromagnetic structure,and an inverse mathematical model of the submarine’s magnetic characteristics is established.Comparing the ellipsoidal magnetic monopole array model with the rectangular and rectangular magnetic monopole array models,simulation results show that the ellipsoidal magnetic monopole array model has higher accuracy.Compared with the conventional magnetic dipole array model,the coefficient matrix condition number of the ellipsoidal magnetic monopole array model is reduced by two orders of magnitude,the computational time is reduced by about 50%,and the relative residuals and maximum relative errors of the model are smaller.The objective optimization model for the degaussing winding model of the submarine is investigated and the improved differential evolution algorithm is applied to the optimization of the degaussing current with good results.By comparing the simulation data with the particle swarm algorithm and the standard differential evolution algorithm,,it is shown that the improved differential evolutionary algorithm of the degaussing current optimization strategy significantly improves the magnetic field compensation efficiency of the X component of the induced magnetic field of the submarine to 93.44% and that of the Z component to 96.40%.It has certain instructive value for the development and research of submarine magnetic field stealth engineering.