Negotiation in constraint-based design

A design problem usually involves multiple perspectives, each with own set of constraints that may interact. The objective of this paper is to develop a methodology to assist in negotiation of constraints from multiple perspectives. The proposed approach is based on qualitative reasoning that provides each perspective with negotiation information for making design decisions. A qualitative constraint network is used to characterize the qualitative and quantitative relationship between design variables. It provides means for tracking dependencies among perspectives for a set of constraints and determines the impact of design changes. When a conflict occurs, effective negotiation strategies are generated. A negotiation procedure for all ill-structured negotiation process is presented. The effectiveness of the negotiation process is improved with the procedure proposed. A valve design problem illustrates the concepts discussed in the paper.