蝙蝠算法改进策略在滚动轴承寿命预测模型中的应用
Application of Improvement Strategy of Bat Algorithm in Remaining Useful Life Prediction of Rolling Bearings
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摘要: 为了实现基于振动数据的轴承寿命预测, 构造了包含时、频统计指标与反三角函数统计指标的健康指标集, 通过比较与均方根指标的余弦相似度和相关系数, 实现了指标集的筛选和约减; 针对基础极限学习机(extreme learning machines, ELM)模型因参数随机配置导致的精度偏低问题, 引入以蝙蝠算法(bat algorithm, BA)为代表的元启发算法; 考虑传统BA易陷入局部最优的弊端, 建立了BA的改进策略, 即采用莱维飞行增强算法的搜索能力, 通过对立学习增强种群的多样性, 从而在保证搜索精度的前提下, 提高搜索效率。利用某滚动轴承的全寿命周期试验数据, 验证了BA改进策略对寿命预测模型的重要贡献。研究结果表明, 无论测试集处于何种工况, 上述预测框架均具有极高的预测精度, 不仅与真实寿命曲线拟合程度较高, 而且在与RBF、CS-ELM等预测模型的对比中, 体现了更强的泛化性能和算法稳定性。Abstract: To realize bearing life prediction based on vibration data, a health index set containing time, frequency statistical indices and inverse trigonometric ones was constructed in this paper. By comparing the cosine similarity and correlation coefficient with the root mean square index, the index set was screened and reduced. For solving the problem of low accuracy of basic extreme learning machine (ELM) model caused by the random configuration of parameters, a meta-heuristic algorithm represented by bat algorithm (BA) was introduced. As the traditional BA was prone to fall into local optimum, an improved strategy of BA was established, which used levy flight strategy to improve the search ability of BA and enhanced the diversity of the population through competitive learning, thereby improving the search efficiency while ensuring search accuracy. The contribution of the BA improved strategy to the life prediction model was verified using the full life cycle test data of a rolling bearing. Results show that no matter what working conditions the test data set is in, the above prediction framework can obtain a relatively high prediction accuracy, not only keeping a high consistency with the true life curve but also showing stronger generalization performance and stability than the RBF and CS-ELM predictive models.