Research And Application On Virtual Characteristics Analyzer System Of Rotating Machinery

Order analysis is one of the most important techniques of rotating machinery involving vibration signal processing and fault diagnosis, and it is the necessary analyzing method in rotating machinery characteristic analysis. It mainly includes order tracking technique and order tracking filtering technique. At present, the foreign rotating machinery special analyzer is at a high level both in accuracy and price besides its setting is not convenient. Because of its need for tachometer, order tracking filter and angle encoder etc., its extensive use in rotating machinery vibration test is limited. Therefore, how to relieve or reduce their limitations becomes the point of research. Just in such a case, Test Center of Chongqing University put forward an order-tracking technique on the basis of Instantaneous Frequency Estimation (IFE), and for the first time implemented order tracking without key-phasor. It greatly simplified settings and implementation, with cost and complexity reduced, and opened a new path for order analysis. However, the researches are just in the preliminary stage and immature. A lot of work is needed so as to put it into engineering application. Although it has great advantages than the traditional and existing order tracking technique, it also has disadvantages which can not be avoided: firstly, it can only be used offline; secondly, each harmonic component must be separated obviously, lastly, it can not meet the criterion of full-period sampling.The task of this paper is just for settling the existing problems in order tracking on the basis of IFE. In one hand, after deep research in this technology, the paper improved two key sides (estimation of instantaneous frequency and computation of order resampling time); the modified algorithms improved computational accuracy. On the other hand, for making up the defects of order tracking based on IFE, variable curve fit Computed Order Tracking (COT) is brought forward, after fully study the relative merits of existing order tracking technique. According to computational accuracy, operating efficiency etc. analysis requests in practical testing, different curve fitting method can be smartly selected to carry out order tracking.Rotating speed computation is one of the key technologies of order analysis. For the situation of provided tacho pulses, usually, adopting polynomial curve fitting the pulse sequence step by step to compute rotating speed, its amount of calculation is large and computing is complex. Therefore, computing method of rotating speed based on...