Harmonic Gears Reduction Gear Reliability Optimization Design And Accuracy Analysis

Harmonic gear drive is a transmission technique that has been developed in1950s.Harmonic gear reducer is mainly made up of a flexspline, rigidity gear and wavegenerator. The motion and power are transferred depending on the flexible deformationof the flexspline. Because of the existence of the flexible components, harmonic gearreducer design involves many factors and the design process is very complex.Harmonic gear drive product based on traditional design method is able to meet theperformance requirements, but the traditional design method has some defects. It isalways timely costs a lot of money and sometimes structural parameters of the designis not reasonable. The reliability of the product is not taken into account; it will resultthat the life of the product can not be guaranteed. The design limitations of thesetraditional restricted the dissemination and use of the harmonic gear. The study of newdesign method of harmonic gear drive has important theoretical significance andpractical value to the development of rational and high efficient harmonic gear reducer.The reliability calculation model of the harmonic gear drive, multi-objectiveoptimization design mathematical models of the harmonic gear drive and factorsaffecting the accuracy of harmonic gear drive had been studied in this paper. The maincontent of this paper is as follows:(1) The knowledge of the harmonic gear reducer is introduced in detail on thebasis of extensive literature review. This knowledge includes the basic principle of theharmonic gear drive, composition, classification and characteristics and so on. Thereliability optimal design method and research status of the harmonic gear drive athome and abroad are summarized.(2) Stress-strength interference model, Monte Carlo method, first order andsecond moment method and genetic algorithm theory are described. Non-dominatedSorting Genetic Algorithm is introduced in detail. The encoding, fitness function, rapidnon-dominated sorting method, congestion and crowding operator, the main flow ofthe binary tournament selection, crossover and mutation process, the implementationof the elitist strategy and its algorithm of the NSGA-Ⅱ algorithm are discussed in detail in this paper.(3) Based on the analysis of the failure modes and the reliability designparameters of the harmonic gear reducer, the reliability model of gear surface wear andflexspline cylinder fatigue are established. In this paper, the reliability formula ofharmonic gear reducer is given.(4) In order to peruse the smallest volume and the maximum reliability andtransmission efficiency, multi-objective reliability optimization design mathematicalmodels of harmonic gear reducer was established in this paper. The NSGA-Ⅱ methodwas used to solve the question in the optimization process. The most sensitive designparameters to affect the harmonic gear transmission reliability were founded out byreliability sensitivity analysis method.(5) Sensitivity formula of influence factors to transmission accuracy of harmonicgear reducer was established on the basis of analysis of sources of error of theharmonic gear. Finally, law of the influence factors to the harmonic gear driveaccuracy was founded by the sensitivity formula.