Reliability Analysis And Optimization Of RV Reducer

RV reducer has many advantages,such as large transmission ratio,long life,compact structure,high transmission accuracy and reliability,is widely used in the field of industrial robots.In recent years,china has invest a lot of energy into researching on the RV reducer,and some achievements have been made in its contact characteristics,transmission accuracy,dynamic characteristics and other aspects.However,there are a lot of indicators in domestic RV reducer such as service life and stability of accuracy,which is far less than similar foreign products.These indicators are closely related to the reliability of the product.Therefore,the research on the reliability of RV reducer in service period,and coming up with the reliability-based optimization design method on this basis,which has important theoretical significance and engineering practical value for the research and development of RV reducer.Based on the theory of Stress-Strength Interference and the theory of Strength Degradation,this paper analyzes the reliability of the weak parts of the RV reducer under the main failure mode considering the fuzziness of strength.And considering the dependent failure between components,the copula function of coupling two-stage transmission sub-components' reliability is derived,on this basis the reliability analysis model of RV reducer is developed.Taking the reliability of the whole machine as the objective function and the reliability of parts as the constraint condition,a reliability optimization design method of RV reducer is proposed.Main research contents of the thesis are as follows:1.Introduce the transmission principle and basic structural characteristics of RV reducer,and based on the classical mechanics theory to analyze the mechanical characteristics of RV reducer.2.Taking contact and bending stresses of gears as random variables,the strength as fuzzy variable,the time-varying reliability analysis model of the parts of RV reducer is developed on the basis of the theory of Stress-Strength Interference and the theory of Strength Degradation.Based on the sub-component reliability required by the model and copula correlation theory,the reliability analysis model of RV reducer considering dependent failure is developed.3.According to the model developed above,the component reliability,system reliability and sensitivity of design parameters of RV reducer were studied;and the influence of strength degradation and failure correlation on reliability is discussed and analyzed in depth.In order to verify the correctness of the model,the system reliability attenuation trend of the theoretical results and the experimental results,which is based on the accelerated degradation test data,are compared.4.Aiming at the maximum reliability and the minimum volume of the entire machine,the multi-objective reliability optimization design model of RV reducer is developed,Genetic algorithm is used to solve the model,MATLAB is used to write solve program of Genetic algorithm.Compared with the conventional volume optimization method,the optimization design method proposed in this paper has better optimization effect and is more in line with the engineering needs.