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Agent-Based Cooperative NC Conceptual Design Zhi Gang Xu Design Technology BinBj=l; 0 I 8. n Bj = 1; illigle :1 :ligile following design constraints can be got: According to the design specifications of lathe, the 1) if the workpiece is heavy, then the workpiece can not move vertically; 2) ifthe workpiece is in high precision, then the workpiece is fixed or has only one translation movement; 3) ifthe workpiece is heavy and in high precision, then the workpiece jig must be adjacent with the base; . . . . . . . . . . . . . . . . . . . 2.3 Module Display The NC conceptual layout model can be expressed precisely by arranging different modules in an explicit way. Fig 1.b is an example of five-axis NC layout model with x,y,z translation movement and A, B rotation. Fig1 .c is the C shape ring list mod.el. It is a close ring from cutter to workpiece. CONTROL MODULE Fig.2 Agent Architecture. Definition 4 : Agent is described as a sextuple : (Aid, Communication, Acquaintance, Cooperate, Assessment, Control). := := : := () :=l lll : := : := () : := lll := llIllegil :=lllIl := 355 4. Management of the Design Process Based on Agent The engineering design is viewed as a distributed system consisting of various autonomous entities completing the special task through cooperation 31. There are two kinds of basic elements in the system: entities and activities. The entity includes the CAD systems (dealing mainly with the graphic issues), users and various agents (information handling). Activity is the process of the entity performing the design process. In the designing process there are also two categories of information: Foreground and Background 4, Table 1 is the list of information and the corresponding activities and participants. Definition 5: The agent oriented cooperative design system DS is a quintuple A,Tr,Ev,OR, among which, A is the set of agents, Tr is the design Transaction, E is the set of events, OR is the organization (including CAD system, various users etc ) . Event is the state change of the system triggered by users, CAD system and agents taking part in the design process, cooperation between agents and the communication with the outside world. In this conceptual model, the product design processes is an activity set of a group of agents and activities undertaking by the cooperative work of agents with the interference of users. 5. Illustration of the Designing Process Definition 6. Event is a sextuple (EID, ESTATE, EPRE, EAG, EAC, EPOST), where EID is the name of events, ESTATE is the present system state, EPRE is the precondition triggering the event. EAG is the set of activated agent, EAC is the action taking by the agent, EPOST is the state caused by this event. Fig.3 give the event description. Eprb- conditio Estate participant Fig.3 Event Description. If the design of a complex NC miller is wanted, which can process turbine blade, the cutter should move simultaneiously in five axis, say x, y, z, A, B, i.e the cutter has 5 DOF (Degree Of Freedom). This is the design precondition. If the part is light, from the designing constraints in chapter 2.2 , the movement of the part has no limitations. Then the EPRO has two hues : 1. x,y,z,A,B five DOF of cutter, 2. the part property is light. Definition 7 : Transaction is a sequence of events, one transaction is an acceptable solution which can satisfy the module constrains and the designing: constraints. T:. . . . . . EID: : : : :T- Y-T-X-H-Base-V-Base-T-Z-R-X in Fig.4 is one feasible NC conceptual structure in Fig. 1 (c). L e _ l m ”l7q H-Base t Fig .4 Multi-Solution in NC layout design 7. Conclusion and Acknowlegement The NC structure conceptual design model based on agent described in this paper is now under intense development. The future work will focuse on the solution qualification mechanism, now it depends mainly on the designers to compare the various conceptual structures, only after the computer tell which is feasible and which is better, can we realize some real form of creativity. This project is supported by the Shandong Provincial Excellent Young Scientist Award. 8. Reference l HU Weigang Development and Practice of Machine Tool Modularization and the Intelligent Supporting System, Doctoral Thesis, Huazhong Institute of Technology, WuHan, 1994, 6. 2 Xu Zhigang, Huang Kezheng, Ai Xing, Cooperative Problem Solving in Mechanical Multi-Agent Systems, Intemational Pro of Workshop on CSCW in Design, 1996, 6, Beijing, P.R.China: 3 Zeng Guangzhou, Sun Boqi. A method for software requirement engineering based on system simulation and its supporting environment. Chinese Joumal o f Computer, 20(3):280-283(1997). 4 H.Suzuki,et a1 Modeling Informati