Abstract
Recently, the design problems for machine products such as machine tools tend to have a large number of evaluative characteristics, and are almost always multi-objective. In such cases, the optimization problem systems often yield a large number of unsatisfactory local optimum solutions due to complexities in the cooperative and conflicting relationships among the design characteristics. Most design optimization methods seldom succeed in finding an ideal optimum solution. In order to overcome this problem, this paper proposes a design optimization method for large-scale problems based on decomposition and hierarchical ordering of characteristics, focusing on the interrelationships among design characteristics. This method begins by carefully examining the characteristics and decomposing each one into as simple sub-characteristics as possible. Next, based on these examinations, all the characteristics are hierarchically ordered and grouped into a number of basic optimization units (BOU). Then, feasible design solutions are searched for using an effective strategy and the system problem is gradually optimized, starting with lower BOU hierarchies and proceeding sequentially to the upper hierarchies. In this paper, this method is applied to the design problem for a simple machine product.
