基于模糊层次分析法的盾构隧道施工风险分析

城市地铁盾构隧道施工常因出现各种事故而未能达到预期目标,即存在风险性。为了研究地铁盾构隧道施工中各种事故发生的概率以及事故造成的损失,采用模糊层次分析法,对杭州某地铁盾构隧道施工进行风险识别和风险估计,并在此基础上采用模糊综合评判法进行风险评价,得出该地铁盾构隧道施工的风险等级。该法不需对判断矩阵进行一致性检验,并能够保证在度量相对准确的基础上,使计算过程得到简化。文章最后对评判结果进行有效性验证,增加了可信度。本次实例风险分析可为同类型工程项目提供借鉴。     

电力隧道工作井深基坑工程的风险识别与模糊评估

根据工程具体情况采用WBS方法按工序进行分解,然后采用故障树法对风险进行分析、识别,建立风险清单。在此基础上,采用模糊综合评判模型进行风险评估,得出基坑施工风险等级,为后来的风险应对提供参考依据。     

Multi-index optimization design for electrical resistance tomography sensor

A multiple index optimization method for ERT sensors is put forward which combines an orthogonal design and fuzzy analysis. This method first establishes a scientific and proper fuzzy evaluation method using fuzzy mathematics to define ERT index satisfaction (ERTIS) and overall ERT index satisfaction (OERTIS) and to construct their satisfaction functions. It unifies all of ERT sensor indices into a single comparable satisfaction value. Then, the OERTIS analysis is developed which allows a set of multiple index orthogonal experiments to be transferred into a single index orthogonal experiment. Where, the uniformity index and the correlation coefficient index of the ERT sensor are set as the optimization objectives. The experiments are set up based on multi-index orthogonal design. The experimental results indicate that the method can derive an evenly distributed sensitivity field and a better image with the optimized sensors, and improve the OERTIS of the ERT sensors by 13.75%.     

基于模糊单神经元PID的比例同步控制研究

针对传统PID算法在液压同步系统中整定困难、稳定性不佳、同步效果不理想的问题,提出一种基于模糊单神经元PID复合算法的双缸耦合同步控制策略,提高同步系统的性能。建立比例阀控非对称缸双缸同步系统数学模型;利用Simulink软件,对比分析传统PID算法、单神经元PID算法和模糊单神经元PID算法的控制效果;最后通过试验验证3种控制策略下的系统同步性能。试验结果表明:使用模糊单神经元PID的耦合控制策略,系统同步误差明显减小,响应速度更快,设计的控制策略有效。     

基于模糊熵与CS-ELM的供输弹系统早期故障识别北大核心

针对供输弹系统早期采集的信号中成分复杂,故障特征难以提取和识别的问题,提出一种基于模糊熵与布谷鸟改进的极限学习机(CS-ELM)的供输弹系统早期故障预示方法。运用改进的可调品质因子小波变换对信号进行滤波降噪,提取各子带信号的模糊熵特征;选取模糊熵值较大的5个子带进行重构,完成降噪并将其模糊熵组成特征向量;运用CS-ELM对所提取的特征向量进行早期故障预示并与ELM的诊断结果进行对比。试验结果验证了该方法的有效性,其预示准确率达90.7%。     

基于模糊评价的六西格玛项目选择研究

由于六西格玛项目选择是成功实施六西格玛项目管理的最重要环节之一,针对六西格玛项目选择的特点,结合模糊评价方法,建立了六西格玛项目选择的模糊评价流程,在分析六西格玛项目评价指标体系的基础上,提出了六西格玛项目选择的模糊评价方法。最后通过重庆某大型企业的实例应用,验证了该方法的合理有效性,提高了企业选择六西格玛项目的精确性,使企业实施最优化项目而获得最大利益和成功,也拓展了六西格玛项目管理应用研究的内容。     

基于AMESim的静压导轨自适应供油系统的研究

提出了一种可以根据载荷变化,自动调整导轨供油压力的系统,从而保持设计油膜厚度趋于不变。并利用AMESim与Matlab软件分别建立液压系统与控制系统模型,对该供油系统进行动态仿真研究。     

Measurement of synchronous machine parameters using Kalman filter based fuzzy logic estimator

This paper presents a new Kalman filter/fuzzy logic approach for estimating synchronous machine parameters from short circuit tests. The technique uses on-line noisy measurements of the short circuit current for estimating direct axis reactances, and time constant synchronous machine parameters. The approach is based on expressing short circuit current as a discrete time linear dynamic system model suitable for the Kalman filter to estimate the parameters. Fuzzy rule-based logic is used to tune-up measurement noise levels by adjusting the covariance matrix. The results show a better convergence using fuzzy logic than those solely using the Kalman filter.     

Bearing performance degradation assessment based on lifting wavelet packet decomposition and fuzzy c-means

Bearing performance degradation assessment is crucial to realize condition-based maintenance. In this paper, a new method for it is proposed based on lifting wavelet packet decomposition and fuzzy c-means. Feature vectors are composed of the node energies of lifting wavelet packet decomposition. Normal and final failure data are used as training samples to build assessment model utilizing fuzzy c-means, and the subjection of tested data to normal state is defined as the degradation indicator, which has intuitionistics explanation related to degradation degree. Results of its application to accelerated bearing life test show that this indicator can reflect effectively performance degradation of bearing. And after discussing the influence of outliers in training set, a robust strategy is proposed.     

修正因子法模糊控制在航空发动机中的应用

针对航空发动机复杂多变、非线性的控制要求,采用一种基于修正因子模糊控制方法设计控制器,并对航空发动机的基本发动机控制模型进行仿真实验。仿真结果表明:基于修正因子模糊控制方法设计的控制器具有超调量小、上升时间和调节时间短的特点;与传统的PID控制方法相比较,可以达到更好的控制效果。