Noriyuki Haga

Constraint-Based Elevator Design Support System

We describe a design support system for configuration of elevators to customer specifications. The knowledge base of the system consists of various design attributes and constraints which form a constraint network. Based on this knowledge base values of attributes are inferred from a customer’s requested specifications by using constraint propagation. After examining the elevator design process, the following functions were found to be indispensable for realizing a practical design support system: 1) modification of the constraint network during the design process when the model changes; 2) control of the direction of constraint propagation; 3) utilization of default constraints; 4) constraint relaxation; and, 5) countermeasure guidance stored in the know-how database by expert designers when conflict occurs during the inference process. The effectiveness of this system was evaluated by application to elevator design, and the design time was reduced from 4–8 hours to 30 minutes for a typical order.