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基于改进FNLM和HSEDO的振动筛轴承早期故障诊断
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作者 王艳 叶敏 +2 位作者 李嘉波 张翠红 卜鹏辉 《长安大学学报(自然科学版)》 北大核心 2025年第1期167-178,共12页
针对振动筛滚动轴承早期故障特征微弱,被强背景噪声和多振源干扰淹没的诊断难题,提出一种基于改进快速非局部均值滤波(IFNLM)和高阶对称包络导数算子(HSEDO)的滚动轴承故障特征提取方法。首先,根据滚动轴承故障信号周期性结构特征,通过... 针对振动筛滚动轴承早期故障特征微弱,被强背景噪声和多振源干扰淹没的诊断难题,提出一种基于改进快速非局部均值滤波(IFNLM)和高阶对称包络导数算子(HSEDO)的滚动轴承故障特征提取方法。首先,根据滚动轴承故障信号周期性结构特征,通过对快速非局部均值滤波(FNLM)算法相似度量和权值分配函数的改进,提出IFNLM算法,滤除轴承原始振动信号中的背景噪声和振源干扰;其次,在包络导数算子(EDO)的基础上,融入对称差分技术和高阶思想,提出HSEDO对降噪后的信号进行解调,从而识别轴承故障特征。最后,搭建振动筛激振器滚动轴承故障试验台,对所提方法的可行性和优越性进行验证。研究结果表明:IFNLM算法具有良好的去噪效果、噪声鲁棒性以及运行效率,IFNLM算法的运行速度相较于改进前提高了77%,约是小波阈值降噪算法的12倍,中值滤波算法的4倍;HSEDO算法具有良好的解调特性和抗干扰能力,在谐波干扰不高于20种的情况下,HSEDO算法处理的信号干扰比高于EDO;所提IFNLM-HSEDO算法与NLM+包络谱、WTD+TEO等现有方法相比,具有更高的故障特征提取能力和执行效率,在取50000个采样点运行时,耗时仅为0.0508 s,且采样点越多其快速性能越突出。研究成果对丰富机械系统故障诊断理论,保证机械设备安全可靠运行具有重要意义。 展开更多
关键词 机械工程 振动筛轴承 故障诊断 ifnlm HSEDO
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A Hybrid Inexact Optimization Model for Land-use Allocation of China 被引量:7
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作者 ZHOU Min CAI Yunlong +2 位作者 GUAN Xingliang TAN Shukui LU Shasha 《Chinese Geographical Science》 SCIE CSCD 2015年第1期62-73,共12页
Land scarcity has become the prominent obstacle on the way to sustainable development for China. Under the constraints of land shortage, how to allocate the finite land resources to the multiple land users in China co... Land scarcity has become the prominent obstacle on the way to sustainable development for China. Under the constraints of land shortage, how to allocate the finite land resources to the multiple land users in China considering various political, environmental, ecological and economic conditions have become research topics with great significance. In this study, an interval fuzzy national-scale land-use model(IFNLM) was developed for optimizing land systems of China. IFNLM is based on an integration of existing interval linear programming(ILP), and fuzzy flexible programming(FFP) techniques. IFNLM allows uncertainties expressed as discrete interval values and fuzzy sets to be incorporated within a general optimization framework. It can also facilitate national-scale land-use planning under various environmental, ecological, social conditions within a multi-period and multi-option context. Then, IFNLM was applied to a real case study of land-use planning in China. The satisfaction degree of environmental constraints is between 0.69 and 0.97, the system benefit will between 198.25 × 1012 USD and 229.67 × 1012 USD. The results indicated that the hybrid model can help generate desired policies for land-use allocation with a maximized economic benefit and minimized environmental violation risk. Optimized land-use allocation patterns can be generated from the proposed IFNLM. 展开更多
关键词 land-use planning uncertain model interval linear programming(ILP) fuzzy flexible programming(FFP) environmental protection interval fuzzy national-scale land-use model(ifnlm
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