Dynamic Simulation Of Harmonic Drive

Harmonic drive is a new transmission technology that utilizes the elastic deformation wave of a flexible component to realize motion or power transmission.It has been widely used in industrial fields including aerospace,robots and CNC,etc,due to its small size,light weight,high single-stage transmission ratio,high precision and compactness properties characteristics.So,it attracts many researches to study it on different levels.However,due to its complexity,many fundamental problems still unresolved,such as the ideal tooth shape,space meshing theory,flexspline strength calculating and kinetics characteristic.It hampers the development and application of harmonic drive gear.Therefore,further study of harmonic drive does not only having a great academic value but also economic value.Flexspline,as an elastic thin-walled flexible cup with small external gear,tends to result in fatigue failure and wear of gear teeth while working under alternating loads.The researches show that the deformation and stress distribution of flexspline play an essential role on flexspline's fatigue failure.Thereby,it is necessary to study the deformation and stress distribution of flexspline.Meanwhile,there has been little research concerning about transmission attributes.Therefore,we intent to analysis the inherent frequency,torsional stiffness and kinematic error of harmonic drive to study and description of its nonlinear transmission characteristics.All the researches are studied using the finite element method.The structure of the paper is organized as follows.Firstly,the structures of three main components of harmonic drive gear,flexspline,circular spline and wave generator with flexible bearing,are designed.And then,3D solid models of these components are established by SolidWorks.Finally,finite element models of harmonic drive gear are established by ABAQUS.Secondly,two sets of harmonic drive gear model,with or without flexible bearing,assembly process are simulated based on ABAQUS/Standard.Then,we make a comparison with results including engagement,the deformation and the stress distribution of cup as well as gear ring of flexspline.The results show that the flexible bearing has little influence on the deformation of the cup and gear ring,but changed the stress distribution of the gear ring.Meanwhile,they all reveal that the harmonic drive gear have space meshing characteristics due generatrix deflection of the cup and gear ring after the assembly.Finally,nonlinear transmission characteristics of the harmonic drive gear without flexible bearing are studied.The inherent frequency of the flexspline and assembly model of harmonic drive gear are calculated by using Lanczos method.And a simulation experiment is designed to study the relationship between the torque and torsion.And then,backlash and torsional stiffness are carried out according to torque and torsion.Later,transmission error from load and rotational speed are discussed.At last,safety coefficient and fatigue life of the flexspline are computed based on FE-safe...