Deriving optimal transmission architecture of planetary gear assembly by mathematical modelling of design parameters

This paper aims to develop optimal transmission architecture, constrained by selection of parameters, to be used as a reference for design of planetary gear assembly comprising of gearsets. These parameters are CAD (Computer Aided Design) geometric attributes of gear members. Planetary gearset is used in fully automatic transmission, in automotive, since this is compact, accommodates gear shifting under load and possesses high torque density, which the parallel shaft variants of gearbox do not. Fully automatic transmission involves high maintenance cost and low fuel efficiency than the manual or the automated manual types. Modelling of transmission architecture has been attempted for hybrid electric vehicle (HEV) as per the available literature, but no mathematical modelling of design parameters has been reported. This research emphasises the significance of mathematical modelling of design parameters for a planetary gear assembly and gear members for deriving optimised architecture. Mathematical models, presented in this work, are gleaned from DoE (design of experiment) based response data and are built utilising General Linear Model (GLM) for obtaining good fit. Material failure based information is expounded in this work for designing vehicle transmission architecture. Effect of design parameters on fuel consumption is also explicated in this article.