Using simulation techniques to determine optimal operational region for multi-responses problems

Most industrial problems involve multiple-quality characteristics. The methods used for optimising such a multiple-response problem are those normally used for dealing with a single response problem, such as the experimental design, response surface methods (RSM) and regression techniques. There is a major difficulty with this traditional approach on the point estimation of the optimal solution, thus the obtained solution may not be practically feasible. In this research, a simulated regression approach via Monte Carlo simulations and the nonlinear optimisation via the trust-region methods were used to determine an optimal operational region (OOR). In practice, an engineer can refer to this region for adjusting manufacturing parameters in the production environment to minimise the response variations. An example with three controllable variables is used to demonstrate the application of the proposed methodology.