PDES—An expert system for constructing the precedence diagram

The techniques of assembly planning have been studied for many years. One of these techniques is the precedence diagram, which shows the precedence or sequential restrictions graphically for assembly. It is an effective tool to analyze the assembly line logically and systematically. It can be used for line balancing so as to enhance productivity and reduce cost. However, it is very tedious to draw a precedence diagram for most assembly operations. This paper presents an expert system approach to the precedence diagram. A new PC-based expert system, PDES, has been developed. PDES can help users to learn about and draw a precedence diagram. The knowledge base of this expert system has been built. It has a hierarchical structure and uses backward chaining in its inference engine. It is menu-driven and very user-friendly. Computer graphics have been used in PDES for explanation purposes. It provides engineers with an effective tool to construct precedence diagrams. Also, the user can learn the precedence diagramming procedure step-by-step via PDES. It also contains many diagramming examples under various situations. In simple words, this system is very beneficial for the assembly planner.