Fuzzy evaluation of product structural design using rough set theory

The problem of fuzzy mapping algorithms with multiple indices having excessively small weighing vector components was analyzed to preclude irrational evaluation results arising in the fuzzy evaluation of product structural designs.The analysis seeks to reduce the primary contributed evaluation index number.This paper describes a knowledge reduction method based on roughness set theory with separate implementations of the evaluation index reduction for product structural designs with perfect and imperfect information systems.The reduced evaluation index is then again processed with the fuzzy mapping.An instance validation of the structural design rationality of a hydraulic torque converter indicates that the reduction before evaluation not only simplifies the calculations,but also avoids irrational evaluation results without affecting the evaluation quality.