Approach toward incremental and interactive planning for concurrent product and process design

The essence of computer-aided concurrent engineering is to address manufacturing issues as a design evolves and to give designers immediate feedback about the manufacturing implications of their design decisions. To do this, the system must maintain dependencies between designs and process plans and be able to incrementally modify the plans in response to design changes. Traditional rule-based approaches to process planning are ill-suited for use in a concurrent environment for a couple of reasons. First, they formulate the planning problem as a one-shot task of finding an optimal sequence of operations. Second, they typically operate on a closed-world assumption that all relevant information is directly available to the planner. By contrast, concurrent engineering requires interaction with specialized modules (e.g., for fixture analysis or mold-flow analysis) that can evaluate or refine parts of the manufacturing plan. To address the special needs of process planning in the context of concurrent engineering, we propose an architecture that views planning as a team activity and describe our current efforts to adapt hierarchical planning to it. In particular, we discuss techniques for making the planning incremental and for coordinating the planning with the specialized modules.