用于磁屏蔽室屏蔽叠层优化的CSA-NSGAII算法

CSA-NSGAII algorithm for magnetically shielded room shield lamination optimization

为提高多层磁屏蔽室的屏蔽性能,进一步降低磁屏蔽室的建造成本,本文将磁屏蔽叠层结构优化视为多目标函数优化问题,在可行的建造成本与建造质量构成的约束下,提出一种分段交叉策略与自适应变异算子改进NSGAII算法(CSA-NSGAII),对屏蔽叠层结构参数进行优化。CSA-NSGAII算法解决了NSGAII算法种群收敛分布不均匀,全局搜索能力差和容易陷入局部最优等问题,从而能够获得屏蔽室最优叠层结构。与NSGAII算法、NSGAII-SDR、g-NSGAII和MOEA/D算法相比,CSA-NSGAII的GD、IGD与Spacing等指标均有显著提升,说明本文提出的CSA-NSGAII算法收敛性能更好,种群分布更均匀。实验结果表明:经优化后的叠层结构在屏蔽性能不变的情况下平均能够节省约14%的建造成本,并在干扰幅值为32000 nT,频率为1 Hz的亥姆霍兹线圈中,实现约70 dB的屏蔽性能。

To improve the shielding performance of a multilayer magnetically shielded structure and to further reduce the construction cost of a magnetically shielded room,this study proposes to treat the magnetically shielded structure as a multi-objective function optimization problem,and to optimize the parameters of the shielded lamination structure using the non-dominated sorting genetic algorithm-II(NSGAII)under the constraints of feasible construction cost and quality construction composition.In this study,the NSGAII algorithm is improved using a segmental crossover strategy with an adaptive variation operator called CSA-NSGAII to solve the problems of the traditional NSGAII algorithm of uneven population convergence distribution,poor global search ability,and easily falling into a local optimum.Compared with the original NSGAII algorithm,NSGAII-SDR,g-NSGAII,and MOEA/D algorithms,the CSA-NSGAII is beneficial in GD,IGD,and spacing,indicating that the proposed CSA-NSGAII algorithm achieves im proved convergence performance and a more uniform population distribution.By applying the algorithm proposed in this paper to the multi-objective optimization design problem of the magnetic shielding structure,the experimental results show that the optimized stacked structure can,on average,save approximately 14%of the construction costs while achieving the same shielding performance,and can achieve approximately 70 dB of shielding performance in a Helmholtz coil with an interference amplitude of 32000 nT and frequency of 1 Hz.