【作者】 张文兴；

【导师】 王建国；

【作者基本信息】 内蒙古科技大学 ， 机械设计及理论， 2009， 硕士

【摘要】 人工神经网络作为动态系统识别、数据挖掘的一种常用的智能工具,已广泛应用于模式识别、图像处理、自动控制、质量建模、机器人、信号处理、管理、商业、医疗和军事等领域。然而,它无法能将相应物理系统直接转化为能被理解的知识表达结果,其“黑箱”特性极大地限制了神经网络的进一步应用。本文主要研究神经网络的规则抽取方法,使神经网络模型输入变量与输出变量之间的关系具有更直观的可理解性,并将从神经网络中抽取的“知识”结合产品质量预测模型实现质量控制参数自动设定的目的,避免了人工凭经验来进行参数设定,对于深入认识生产规律、改善生产工艺、提高产品质量有着重要的意义。论文主要的创新性成果有以下两方面的内容:(1)提出了基于优化激活函数的神经网络规则抽取方法,并将其应用于热镀锌生产中的数据挖掘和知识发现,克服传统神经网络产品质量监控模型中“解释性差”的难题。通过加入指数变量的惩罚项,使激活函数的输出值更趋于0和1的二值化,提高了规则的覆盖率,以变量区间的形式成功的提取出产品原材料参数、生产控制参数与产品质量间的对应关系,为生产过程监控和质量管理提供有效的分析方法和控制手段。应用锌层重量的实际生产数据进行模型验证,分析结果表明:用本文方法提取到的知识规则覆盖率达到94.7%。(2)提出了多变量产品质量模型中过程控制参数的设定方法。首先运用规则抽取方法,从现有的生产数据中找出知识规则作为过程参数的取值区间,同时根据生产数据建立质量预测模型并利用它在规则范围内准确的预测出控制参数值,从而达到过程参数预测控制的目的。本文提出的过程参数预测控制方法搜索空间小,且算法速度快,应用某钢厂实际的镀锌生产数据验证了本文方法的有效性。更多还原

【Abstract】 Although ANN (Artificial Neural Network) has been widely used in pattern recognition, control and decision-making, system modeling, the inherent“black box”characteristic of ANN has greatly limited their further application. This work studies the rule extraction method of ANN, make clear the relationship between inputs and outputs of ANN and make the model easy to understand. What is more, we apply the“knowledge”extracted from ANN to production quality modeling in order to automatic set the quality parameters combining with quality prediction model, which avoid the artifical seting by people’s experience. It has the important significance for deeply understanding the production law, improving the production technology and the product quality.The main content of this work is as follows:(1) The method of the rule extraction of ANN based on optimized activation functions is put forward, which is applied to data mining and knowledge discovery in the production of hot-dip galvanizing and overcomes the defect of“poor explanation”of the traditional ANN. The penalty term of the exponential variable is applied to make the values of the activation function have a better approximation to binary values: 0 or 1,which is helpful for rule extraction. The corresponding relationships among the raw materials parameters, control parameters and the product quality are extracted in the form of production rules, which provides effective means of analysis and control in production process monitoring and quality management. The results of model verification using actual product data of zinc coat weight showed that the coverage rate of the knowledge rules extracted from our method has reached 94.7%.(2) The prediction-control method of process control parameters in the multivariable production quality model is proposed. The knowledge rules in existing production data are extracted to be constraint conditions of parameters setting problem. Simultaneity, the quality prediction modeling was built based on process control parameters, which was used to find the exactly control parameters in the range of the rules. The proposed method has the advantages of small search space of problem domain and fast convergence during optimization, and has been successfully applied to off-line navigation system for zinc weight control in hot-dip galvanizing strip.更多还原