Intelligent Decision Support for Assembly System Design

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The design of an assembly system is a complex problem, often requiring large teams of engineers with significant experience and expertise. Based on studies of the product design, these teams must select an assembly sequence, generate a corresponding process plan, identify the resources capable of completing the tasks in the process plan, and group these resources into a system of workstations to accomplish the required assembly operations. The resulting system must be economically viable but have sufficient capacity to meet production requirements. The successful, timely design of such an assembly system depends on the team’s ability to effectively share and communicate large volumes of information and have rapid feedback concerning cost, producibility, quality, and other important engineering criteria. Unfortunately, few available tools focus on fabrication or assembly: Those tools that do are often unable to share data. As a result, design teams are forced to do much of the work manually and are unable to effectively share information. Even large manufacturers find their teams spending considerable efforts just to enter the same data into multiple computer systems. Much work has been done to address various aspects of the assembly system design problem. For example, systems have been developed for modeling (Dixon 1988; Pratt and Wilson 1985; Luby, Dixon, and Simmons 1986), assembly design (Boothroyd and Dewhurst 1987), sequence selection (Lui 1988; Homem de Mello 1989), process planning (Delchambre, Coupez, and Gaspart 1989), and assembly line design (Gustavson 1988; Graves and Holmes 1988; Cooprider 1989). As a result, much has been learned about these particular areas. However, little work has been done to integrate these systems. Work on integrating these systems has required limiting assumptions, such as the use of embedded domain-specific knowledge (Sriram et al. 1989), or application to parametric products only (Phillips and Aase 1990). The goal of this work is to provide assembly system design teams with an integrated environment that is capable of intelligent decision support for work on complex assemblies. The system was developed through the combined efforts of a group of software developers and a team of electric, industrial, and mechanical engineers. The engineers have worked on design and assembly for 20 years, doing both basic research and consulting work with several large manufacturers. The choice of functions for the system was driven by the engineers’ need for a set of tools to handle recurring problems in their consulting work. The tools address issues that occur over a wide range of industries and that are critical to the design of technically sound, yet economical assembly systems.