Application of Multi-objective Optimization for Optimization of Half-toroidalContinuously Variable Transmission

Among different goals defined in vehicle design process, fuel consumption (FC) is one of the mostimportant objectives, which significantly has taken into account lately, both by the customers andvehicle manufacturers. One of the significant parameters which impacts the vehicle FC is theefficiency of vehicle's power train. In this paper, a half-toroidal continuously variable transmission(CVT) is considered as the vehicle power train. Its efficiency is sensitive to its geometry, and variationof its geometry can result the vehicle FC reduction. On the other hand, geometry variation affects itsweight and fatigue life, which are considered as major contributing factors in the power train design.This paper aims to optimize half-toroidal CVT in order to minimize its weight, FC of the vehicleequipped with it, and provide the desired fatigue life. After introducing half-toroidal CVT, the methodof calculating the mentioned objective functions is presented. A specific importance weight for eachobjective is considered. These weights are functions of their related objectives. A single objectiveoptimization is implemented for each objective, and their optimal values are obtained. Then, theseobjectives are optimized simultaneously using Global Criterion method