Research On Evaluation Method Of Rolling Bearing Performance By Evidential Reasoning Rule Under Perturbation Condition

Rolling Bearing is an important component of rotating machinery,and its running state will directly affect the safety of whole rotating machinery system.Rolling bearing has the advantages of small friction resistance,high mechanical efficiency and small power consumption in transmission,and is widely used in industry,transportation and other fields.The failure of rolling bearings at work will cause downtime accidents,affect the production schedule,lead to economic losses and even casualties.At the same time,as rolling bearings are widely used in various complex scenarios,their operating environment has become more complex and demanding.Therefore,real-time evaluation of the performance status of rolling bearings is of great significance for improving the reliability of bearings,timely locating the weak links of bearing system,and formulating reasonable maintenance plans.Most importantly,rolling bearings have high requirements for the precision of device during operation,and are easily affected by the perturbation of nonlinear factors such as heavy load,high temperature and other complex working environments,which may lead to the deformation or fracture of bearing,thereby reducing reliability of the bearing.At present,the research on bearing perturbation is relatively insufficient,so the analysis of perturbations influence on bearing performance evaluation has also become a key issue.To resolve the above problems,this paper constructs a rolling bearing performance evaluation model and considers the influence of perturbations.Based on the vibration signals collected during the running of rolling bearings,the time domain and frequency domain features are extracted as evaluation indicators,and the performance evaluation methods are deeply studied,which can be divided into the following three aspects:(1)The time domain indicators and frequency domain indicators of vibration signals are extracted as evaluation indicators.Considering that bearings are affected by perturbations,there is uncertainty in the evaluation indicators.The evidential reasoning(ER)rule can effectively deal with the information uncertainty problem,and effectively integrate quantitative information and qualitative knowledge.At the same time,as a generalization of Bayesian theory,the ER rule constitutes a joint probabilistic inference process,and the inference process is clear,transparent and interpretable.Therefore,this paper constructs a performance evaluation model of rolling bearings based on the ER rule to effectively resolve the problems of bearing indicator uncertainty,complex operation mechanism,and opaque reasoning process.After experimental verification,the performance evaluation model based on the ER rule can effectively evaluate the performance of rolling bearings,and lay a foundation for subsequent analysis of the perturbation problems existing in bearing operation.(2)Due to the high precision of rolling bearings,they are easily affected by perturbation factors during operation,leading to changes in indicator data,that is,Data Perturbation.Therefore,on the basis of performance evaluation model,the perturbation analysis is introduced,and the performance reliability evaluation model is proposed.This model quantifies the perturbation information by defining the perturbation intensity and perturbation variables,defines the perturbation coefficient to analyse the influence of perturbation on bearing performance to measure reliability of bearing.Through the experimental verification,performance reliability evaluation model can effectively analyse the influence of different perturbation factors on bearings,and obtain the adaptability of bearings to perturbations.(3)In practice,rolling bearings usually work together to form a complex system,and the abnormal indicator information caused by perturbations of system can be reflected in the evidence reliability,that is,Parameter Perturbation.To comprehensively consider the inherent properties and external characteristics of the neutron bearing in system,the static reliability and dynamic reliability are introduced,and the bounded parameter perturbation factor is defined to describe perturbations.By calculating the performance evaluation results,the perturbation sensitivity analysis is carried out on the first partial derivative of the perturbation factor,and the “poor-bearing” in the bearing system is accurately located.It is verified by experiments that the first partial derivative can effectively analyse the influence of perturbation on the sub-bearing,which is of great significance to weak link of the accurate positioning system.