Study On Tilting-pad Sliding Bearing Dynamic Parameters Identification Method Based On Active Magnetic Bearings

The development trend of modern rotating machinery with higher load and higher speed brings the mechanical components,especially bearings used to support the rotor more stringent technical requirements on the reliability and dynamic performance;at the same time,only the dynamic behavior of bearing-rotor system can be analyzed accurately after definite cognition and reliable prediction of bearings dynamic effect.In this paper,the theoretical identification and experimental identification method of dynamic parameters of the main sliding bearings-tilting pad sliding bearings were studied in terms of both theory and experiment.Theoretically,by deducing the formula of modern lubrication theory and combining perturbation method,the dynamic parameters of tilting pad sliding bearings were theoretically identified.The theoretical identification results were applied to the stability analysis of the actual rotor-bearing dynamics system,and the same frequency reduction model of tilting pad sliding bearings and the algorithm of the electromagnetic bearings for stability control and dynamic excitation form were deduced,which provided a theoretical basis for the identification and control experiments.Experimental aspects,an electromagnetic bearing-tilting pad bearing-rotor test rig was built by which a stability control experiments were completed by the use of electromagnetic bearings in the case that tilting pad bearing dynamic effect was insufficient to maintain system stability.In addition,a dynamic parameter identification test rig for tilting pad sliding bearings based on electromagnetic bearing excitation was constructed,a modal analysis of the experimental rotor was made,and the theoretical identification of the bearing was calculated,and a variety of potential exciting force forms for bearing parameter identification experiments were explored,and the sine excitation experiment was accomplished.The dynamic parameters of tilting pad sliding bearings were measured and compared with the theoretical identification values,the error causes and the coping schemes were analyzed.The study on the identification test method of tilting pad sliding bearings based on magnetic bearings and the experiment of rotor-bearing stability control are important for further widening the application of electromagnetic bearings in the traditional rotating machinery.At the same time,based on the non-contact excitation form of electromagnetic bearings,it also broadens the dynamic parameter identification experiment of tilting pad sliding bearings,which provides a more effective and flexible medium for the practice of more precise and frontier identification algorithms.