柴油机缸套活塞组磨损状态的识别研究机械电子工程专业论文.docxVIP

中南大学硕士学位论文 中南大学硕士学位论文 摘要 摘 要 缸套一活塞组是柴油机的动力源，尽管该组件在柴油机中故障率 并不是最高的，然而一旦它出现异常磨损，轻则造成整机性能变差， 重则整机报废。因此，对柴油机缸套一活塞组进行状态监测，对于保 持柴油机良好的工作状态具有重要意义。 基于以上考虑，本文进行了柴油机缸套一活塞组工作状态识别的 研究。首先，本文对机身振动信号和活塞与缸套之间撞击情形进行了 分析，建立了二者之间的映射关系，并明确了柴油机机型、运行工况 等因素对映射关系的影响；其次，考虑到柴油机机身振动信号是非平 稳随机过程，本文主要利用了小波包时频分析方法对机身振动信号进 行处理，绘制了小波包三维时频能量图，提出主撞击能量特征参数作 为监测缸套一活塞组工作状态的重要依据；再次，本文将遗传算法与 神经网络结合，改善了网络性能。在遗传算法初步优化权值的基础上， 再进行BP网络的训练和识别，充分利用神经网络的非线性映射能力， 实现了柴油机缸套一活塞组工作状态的识别；最后，对不同机型的缸 内部件不同的磨损失效形式进行了实验，验证了本文提取特征参数的 有效性。 结果表明，振动分析法能在不拆机的前提下准确的识别出柴油 机缸套一活塞组的工作状态。该方法简单可靠，具有良好的工程应用 —1L目 日lJ景。 关键词缸套一活塞组，振动信号，特征参数提取，状态识别 AB AB STRACT Cylinder-piston assembly is the power source of a diesel engine． Though failure rate of the assembly isn’t the highest，once it appears abnormal wear,the operation quality of the diesel engine is decreased than before，or even the diesel engine iS destroyed．Thus．monitoring the working state of cylinder-piston assembly is very important for keeping diesel engine in a good operation condition． Based on the reasons above，a research on the identification of working state of the cylinder-piston assembly is carried out in this thesis． Firstly,the thesis analyzes the vibration signal of diesel engine surface and the crashing process between piston and cylinder,establishes the mapping relationship between them，and masters the influence factors that is the diesel engine models，operating conditions and SO on．Secondly, considering that the vibration signal is non-stationary stochastic process， the thesis mainly uses wavelet packets to deal with the vibration signal． plots the three—dimensional time—frequency energy chart of the wavelet packets，and proposes using characteristic parameter of the main impact energy as an important basis to monitor cylinder-piston assembly working state．Thirdly,the thesis combines genetic algorithm and neural network， which will improve the network performance．On the basis of primarily optimizing the weight distribution with genetic algorithm，the thesis trains and