Construction Of RV Reducer Load Spectrum Based On Multi-source Data

Industrial robots are an important carrier for the digitalization,intelligence and informatization of the manufacturing industry,and are known as "the pearl at the top of the manufacturing crown".And the technical level of industrial robots is an important indicator to measure a country’s technological innovation and high-end manufacturing level.At present,domestic industrial robots are constantly approaching the international first-class level in terms of speed and accuracy,but the failure rate is high during operation,advanced functions and performance are difficult to maintain,and reliability problems are prominent.As the core functional component of the industrial robot,the reliability of the RV reducer directly affects the reliability of the entire industrial robot.By carrying out the reliability test and reliability design research of the RV reducer,it will help to improve the reliability level of the domestic RV reducer and increase the market share of the domestic RV reducer.The load spectrum is an objective basis for reliability design of mechanical and electrical products and components,and is a prerequisite for reliability bench tests and fatigue tests that simulate actual working conditions.Therefore,it has important theoretical significance and practical application value to study the scientific and reasonable construction method of load spectrum of industrial robot RV reducer.Aiming at the problems of long load test cycle and high test cost caused by many application scenarios of industrial robots,this paper proposes a method for constructing load spectrum of RV reducer based on multi-source data,which mainly includes: field data acquisition,simulation data acquisition,load signal preprocessing,load parameter extrapolation,program loading spectrum compilation,etc.The specific research contents are as follows:（1）The transmission principle and structural characteristics of the RV reducer are analyzed,and the characteristics of the use scenarios of industrial robots under different working conditions and the acquisition through the control system are analyzed and discussed.An industrial robot data acquisition system based on the OPC UA protocol was developed,and the load data such as angular coordinates,speed,and torque of the RV reducer were measured.（2）In view of the complex working conditions of industrial robots and many factors affecting the load,it is difficult to obtain a large number of RV reducer working condition load data.Therefore,the parametric model and dynamic model of the RV reducer based on Recurdyn are established,the simulated load data is obtained,the measured load data is supplemented,and the load data is preprocessed at the same time.It mainly includes removing trend items,removing singular point noise reduction and normalizing the load data to prepare for the subsequent load spectrum extrapolation.（3）Synthesize the preprocessed multi-source load data to establish the torque-speed-frequency matrix of the RV reducer.Aiming at the discrete characteristics of the torque signal,a clustering-based torque load classification method is proposed.For each type of torque load condition,based on the load distribution characteristics of the RV reducer speed,a load extrapolation method based on the mixed Weibull distribution is proposed.Aiming at the problem that the number of basis functions is difficult to choose in the mixed Weibull model,the optimal number of basis functions is determined by using naive Bayesian clustering.At the same time,the EM algorithm is used to solve the problem of difficult parameter estimation in the mixed Weibull model.Finally,an extrapolation model of the load parameters of the RV reducer is established.（4）Based on the load extrapolation model,the load spectrum of the reliability test of the RV reducer was compiled and the reliability test scheme of the RV reducer was proposed.Determine the load extrapolation multiple by calculation,and solve the total frequency of load action.The load is divided into 8 intervals by the Conover ratio coefficient,and the cycle frequency of the load in each interval is calculated,so that the eight-stage program loading spectrum of the RV reducer is compiled.Based on the basic principle that the reliability test does not change the failure mechanism and failure mode,a reliability test scheme of the RV reducer based on the program loading spectrum is established.As a result,a set of methods for the measurement,construction and application of the load spectrum of the RV reducer for industrial robots is formed,which provides a theoretical basis for the subsequent reliability test of the RV reducer based on the load spectrum.