Multistage Multiobjective Optimization of Gearboxes

The problems of kinematic and strength designs of multispeed gearboxes are formulated as multiobjective optimization problems. In the kinematic design stage, the speeds of all the shafts, the number of teeth on various gears and the gear module are selected so as to minimize the deviation of output speeds from specified values and the overall center distance of the gearbox. In the strength design stage, the face widths of the various gear pairs are chosen so as to minimize the volume of the material of the gears and to maximize the power transmitted by the gearbox. A goal programming approach is suggested for the solution of the multiobjective nonlinear constrained optimization problem by treating the ideal feasible solutions as the goals for the corresponding objective functions. The utility of the resulting computer program is demonstrated through the design of six- and 18-speed gearboxes. The present methodology offers the feasibility of automating the design of gearboxes by incorporating all the (conflicting) design requirements and objectives.