The Rotot-Stator Rubbing Analysis Of Rotor Mechiney And Tis Vibration Control

With the development of modern industry, the rotating machines are required to be more high-speed, more high-precision and more intelligent. As the structure getting more and more tight and the clearance between the rotor and stator getting more and more small, the rubbing fault happen more and more often. The harmfulness it brings in is negative and may lead to mechanical wear which may result in huge economic loss for the factory and some may even destroy the machine. Therefore, how to recognize and eliminate the early rubbing fault has great significance for industrial development. In this paper, the phenomenon of the rubbing fault is analyzed through numerical simulation and experimental research, the time domain methods and frequency domain methods are applied to extract fault characteristics online. In order to eliminate the rubbing fault, PD algorithm and Model Reference control method are applied to reduce vibration and increase the clearance between the rotor and stator based on the electromagnetic bearing. The main contributions of this dissertation are summarized as follows:1.Building up the rotor rubbing force model, the polynomial which is based on three variables of clearance, frication and stiffness is used to simulate the rubbing force. Using the Dyrobes to obtain the simulation results and analyze characteristics of the vibration signal. Using the Labview to deal with the vibration signal, especially for the orbit which is decomposed into forward procession and backward procession and the percentage of the forward procession indicates the stability of the rotor system. On the Bently test table, three cases of experiments are conducted to analyze the results of the rubbing with different rubbing factors such as rubbing stiffness, friction coefficient, rubbing surface area and speed.2.1n order to simulate the rubbing fault in the real factory, large rotor-bearing systems are constructed, using different rubbing device to compare the different phenomenon between the small test table and large test table, and finally provide the basis for the actual.3.On the test table which is based on electromagnetic bearing, the relationship of electromagnetic force, current and clearance is achieved by static calibration experiment. Then a four degrees of freedom control model of single plain is set up, using PD control method to generate additional stiffness and damping, different proportional coefficients and integral coefficients are adjusted to achieve the purpose of reducing vibration.4.The BAR(Backward-Auto-Regression) model is established using the vibration displacement dates which is measured on the point near the control plain, and the system parameters are recognized, with the input of small mass unbalance, the control model which is based on reference model is built. Using the OR38to monitor the vibration signal online, and the experimental results show that this control algorithm can effectively reduce the multiple frequency vibration.