Target cascading for product family development When designing a family of platform-based products, one must identify the tradeoffs that are a consequence of shared systems, subsystems, and/or components. These tradeoffs exist because the products are no longer opti- mized for their individual performance, but for the family as a whole. The shared elements of the product family in- fluence the performance of the individual products.
A Pareto-based approach that quantifies the afore- mentioned tradeoffs was proposed by Nelson et al. (1999). The first step in this method is to formulate individual design problems for each product. The problems are then combined into one family problem using a multicrite- ria optimization formulation that includes the individual product requirements. By introducing an equality commonality constraint one can specify the product elements to be shared. Solving the multicriteria problem for the Pareto set one can then visualize the design tradeoffs, and In order to exploit the product family structure, the design problem is formulated as a hierarchical optimization problem, as investigated by Fellini et al. (2000). The top level problem addresses family attributes, while lower levels address attributes associated with particular elem- ents. To achieve this within the modified target cascading formulation presented in this article, family targets are