From the paper: G. Taguchi [Introduction to quality engineering. (1986)] defined the product quality as the total losses of society. The main concept of Taguchi’s quality engineering concentrated on off-line quality control including the system design, parameter design, and tolerance design. In the step of parameter design, the optimum combination of the control factors is selected so that the output of product is insensitive to the effect of noise factors. Robust design plans a major role in this phase.
We present the problem of robust design under the fuzzy environment. By defining the linear membership functions for relaxing the conditions on the process mean and variance, we can adopt the minimum criterion for aggregating the membership functions of fuzzy sets and obtaining the optimal solution of the problem.