Research On Design Method Of Compound Tooth Profile Of Harmonic Drive

Harmonic drive drive is widely used in industrial robots,aerospace,radar systems,optical instruments and general machinery because of its unique advantages such as large transmission ratio,small volume,high transmission accuracy,small backlash,and the ability to transmit motion to sealed space.In recent years,with the rapid development of industrial robots,harmonic drive,as an important transmission component of industrial robots,has also received enough attention.Aiming at the problems of low transmission accuracy caused by too large meshing backlash of involute tooth profile and difficulty in manufacturing and testing of double circular arc tooth profile and S-shaped tooth profile,this paper presents a design method of composite harmonic drive tooth profile,and establishes an optimization model of composite tooth profile.The deformations of flexspline under different loads are solved,and the minimum meshing backlash of composite flexspline is obtained by objective optimization.The comprehensive performance of composite tooth profile is verified by experiment.The specific research contents are as follows:On the basis of shell theory,the theoretical deformation function of flexible wheels under different cam contour curves is derived;the deformation function of flexible wheels under load is established considering the clearance of bearings,the clearance between bearings and flexible wheels and the magnitude of loads;the meshing theory of harmonic drive is derived by coordinate transformation and the rotation angle relationship of flexible wheels;Method of calculation.The optimization of tooth top and tooth height are introduced into the design of composite tooth profile as variables,and different composite tooth profiles are designed by using different optimization curves.The trajectory simulation and meshing backlash analysis of compound tooth profile under different top optimization quantity,tooth height optimization quantity and optimization curve.The optimization model of compound tooth profile design is established.The objective optimization is introduced.The top optimization and tooth height optimization are taken as design variables,and the minimum meshing backlash is taken as the optimization objective.The compound flexible gear profile with minimum meshing backlash is obtained.The data are imported into LS-DYNA to analyze the deformation law of flexspline under different load conditions,solving deformation function of flexspline under different loads.The deformation curve of flexspline is fitted by MATLAB,and the fitted deformation curve of flexspline is substituted into the meshing theory of harmonic drive to solve the tooth profile of rigid wheels under different loads.Taking HS-32-100 harmonic drive as an example,the designed composite harmonic tooth profile is processed and the prototype of the composite harmonic drive is obtained.Torsional stiffness,backlash,transmission accuracy and meshing teeth number of HS-32-100 composite tooth harmonic drive were tested.