Abstract
The author considers the issues about the robust optimization raised by Prof. Arakawa at the last JSME D & S symposium in 2014. The most known definition of the robust design is that variation of the objective function value is the smallest under the variations of the design variables as well as the minimization of the objective function values. Many researhers have formulated that the objective function for the robust desig as the weighted sum of the deterministic objective function value and the variations. Then, many researches concerning the robust design would like to emphasize the difference between the deterministic and robust optimum design to show the importance of considering uncertainties. On the other hand, his raised issue is that there exists the problem that the robust optimum design is largely shifted by slightly change of the design conditions according to the robust design definition above. The large change might be desirable under the usual definition of the robust design, but the change itself is the issue. In this study, the author shows another gap between the obtained results under and the expected results and then, discisses the expectation to the robust design.
