Fatigue Life Study And Structural Parameter Optimization Of Short-cup Flexible Wheel Harmonic Drive

Harmonic reducer is widely used due to its advantages of large transmission ratio,high load bearing and small size.As the application requirements increase,the space left by industrial robots and aerospace equipment for harmonic reducers is becoming more and more compact.The short flexspline harmonic reducer greatly reduces the volume of the reducer,but it also brings about the problem of easy fatigue damage.At present,there are few theoretical researches on short flexspline,which restricts the development of related harmonic reducers.In this paper,the fatigue life of short flexspline harmonic drive is studied through theoretical analysis,finite element calculation and performance test,.First,the short flexspline was divided into two parts: the cylinder body and the bottom.Establish the corresponding displacement function respectively and combine with the geometric equation to derive the theoretical stress calculation method of the flexspline.The theoretical value was solved by Matlab programming,and compared with finite element value.Second,based on the three fatigue life analysis methods of stress,strain and critical plane,the fatigue life of the cylinder and the bottom of the short flexspline is calculated in turn.Then the Fe-safe software is used to calculate the fatigue life of the short cup flexspline.The fatigue life calculated by each method is compared,and the reasons for the difference are analyzed.On this basis,the orthogonal method is used to analyze the sensitivity of the design parameters of the short flexspline to its fatigue life,and the genetic algorithm is used to optimize the parameters of a certain type of harmonic reducer with short flexspline.The theoretical fatigue life of flexspline is 7.3 times that before optimization.Finally,the stiffness test device and fatigue life test bench of the harmonic reducer were designed and built.The stiffness measurement and fatigue life test of the harmonic reducer prototypes before and after optimization were carried out.On the premise that the stiffness meets the standard,the fatigue life of the short flexspline has been increased to more than 180 minutes to meet the design requirements.The research results of this paper enrich the design methods of the short flexspline,and have certain guiding significance for improving the fatigue life of the short flexspline harmonic drive.