A New Reliable Operating Region Design Method

The reliable operating region, which is the set of all possible points in the design space that satisfy the reliability requirement, is capable to improve the reliability of products in the design stage. However, the reliable operating region has an irregular geometry shape and it is hard to derive an explicit expression; therefore, its practicality is poor. In order to obtain a more convenient approach, this paper proposes a reliable hyperrectangle operating region, which is expressed by permissible intervals for each design parameter and has the advantage that design parameters are decoupled. An iterative algorithm that seeks an axis-parallel reliable hyperrectangle with maximum volume is proposed. Starting from a design point with target performance, the lengths of the sides of the reliable hyperrectangle are iteratively updated. Theoretical analysis shows that the proposed algorithm is convergent. Furthermore, we extend the proposed methodology to deal with design space constraints. Some numerical examples and engineering cases demonstrate that the proposed algorithm can achieve the requirement of reliability efficiently.