Interval approach to robust design

Abstract

PurposeAims to present a novel approach for the worst‐case, robust design (RD) of an electromagnetic system able to overcome some discretionary aspects of the available methods.Design/methodology/approachThe proposed methodology is based on a suitable application of the interval arithmetic and considers the width of the interval Taylor extension (WITE) of the performance function (PF) as a valuable robustness index (RI). In particular, the most robust stationary point is obtained by looking for the minimum of a continuous, non‐differentiable function thanks to the properties of WITE.FindingsThe method furnishes a reliable classification of the robust solutions with PFs expressed by either mono or multi‐dimensional polynomial forms and provides the over‐bounding of the PF without additional computational efforts.Research limitations/implicationsLimitations concern the necessity of an analytic formulation of the system performance. The IA approach may lead to lose some robust solution.Practical implicationsA RI can be assigned in analytic form and it can be suitably used as a figure of merit in a multi‐objective optimisation problem.Originality/valueThe use of the interval analysis for the worst‐case, RD of an electromagnetic system is original. The system designer may find the most robust stationary solution by means of a continuous, non‐differentiable function.