基于混沌振子的小型挖掘机回转支承早期微弱故障信号检测

发布时间：2018-03-09 14:25

本文选题：混沌系统　切入点：微弱信号检测　出处：《西安建筑科技大学》2014年硕士论文　论文类型：学位论文

【摘要】：在工程应用中，回转支承是大型低速重载设备的关键部件，极易受损，其原因是这类设备承受载荷大、转速低，容易造成滚珠和滚道的点蚀和塑性变形等疲劳损伤。当回转支承存在潜在微小故障时，长期运行可能导致事故发生，轻则影响机器正常工作，重则导致恶性事故发生造成巨大的经济损失。由于回转支承不便拆装维修且工期长，其内部磨损或其它缺陷的检测就显得十分困难，而且存在不确定外界因素，易造成危险或较多的资源浪费，因此回转支承的故障识别及诊断技术具有重大的研究与实际应用价值。为了提前发现早期的微弱故障信号，本课题主要研究了如何利用Duffing振子间歇混沌现象来检测小型挖掘机回转支承早期微弱故障信号频率。本课题所做的工作主要包括以下几个方面： (1)研究几种典型的混沌动力学模型（Duffing系统、Lorenz系统、Logistic系统和变形Rossler系统等）。研究阻尼、周期摄动力幅值、初始条件等参数对混沌系统的影响。 (2)研究混沌的判据。利用Poincare截面法、Lyapunov指数法从不同的角度判定变形Rossler系统的临界状态。 (3)变形Rossler系统对含有噪音的微弱信号进行幅值检测，通过分析比较，拟选择变形Rossler混沌系统应用于弱信号参量的检测。此外介绍了未知任意频率信号的检测方法。 (4)由于传统故障诊断方法对检测回转支承等工程机械出现早期微弱信号存在弊端。为了更好的检测出故障特征信号，采用混沌系统利用其对微弱信号的敏感性以及对噪音的免疫力，，结合小波分析进行微弱信号的检测，将此方法用于工程实际中可以有效的检测微弱故障信号。
[Abstract]:In engineering application, slewing bearing is the key part of large low speed heavy load equipment, and it is easy to be damaged because of the heavy load and low speed of this kind of equipment. It is easy to cause fatigue damage such as pitting and plastic deformation of ball and raceway. When there is a potential minor fault in the slewing bearing, the long-term operation may lead to an accident, and the light will affect the normal operation of the machine. Heavy accidents lead to huge economic losses. Because of the inconvenience of disassembly and repair of slewing bearings and the long construction period, it is very difficult to detect internal wear or other defects, and there are uncertain external factors. It is easy to cause danger or waste more resources, so the fault identification and diagnosis technology of slewing bearing has great research and practical application value. In this paper, we mainly study how to use the intermittent chaos of Duffing oscillator to detect the frequency of weak fault signal in the early stage of rotary support of small excavator. The work of this topic mainly includes the following aspects:. 1) several typical chaotic dynamics models, such as Logistic system and Rossler system, are studied. The effects of damping, amplitude of periodic perturbation force and initial conditions on the chaotic system are studied. (2) the criterion of chaos is studied. The critical state of deformed Rossler system is determined from different angles by using Poincare section method and Lyapunov exponent method. The deformed Rossler system detects the amplitude of the weak signal with noise. Through analysis and comparison, the deformed Rossler chaotic system is chosen to be applied to the detection of weak signal parameters. In addition, the detection method of unknown arbitrary frequency signal is introduced. 4) because of the disadvantages of the traditional fault diagnosis method to detect the weak signal in the early stage of engineering machinery such as rotary support, in order to detect the fault characteristic signal better, The chaotic system is used to detect weak signals by using its sensitivity to weak signals and immunity to noise, and wavelet analysis is used to detect weak signals. This method can be used to detect weak fault signals effectively in engineering practice.
【学位授予单位】：西安建筑科技大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TU621;TN911.23

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