AGENT-BASED PRODUCT DESIGN AND PLANNING FOR DISTRIBUTED CONCURRENT ENGINEERING

Abstract

This thesis describes a multi-agent approach to the integration of product design, manufacturability analysis and process planning in a distributed manner. The objective is to develop a distributed concurrent engineering system to allow geographically dispersed entities to work cooperatively towards overall system goals. In the thesis, an agent-based concurrent engineering system concerning product design and manufacturing planning, and its fundamental framework and functions are presented. The proposed model considers constraints and requirements from different product development cycles in the early development phases and fully supports the concept of design-for-manufacturability. This methodology uses conflict resolution (CR) techniques and design-improvement suggestions to refine the initial product design. The model comprises a facilitator agent, a console agent and six service agents. Each service agent is used to model different product development phases, and the console agent acts as an interacting interface between designers and the system, while the facilitator is responsible for the decomposition and dispatch of tasks, and resolving conflicts of poor designs. The contributions of the thesis are fivefold. Firstly, a framework for integrating all the essential components of concurrent engineering is developed. All the components interact dynamically, addressing different manufacturing planning issues simultaneously, thereby avoiding costly iterations. Secondly, the implementation methodology provides an effective way of making heterogeneous legacy software tools capable of communicating and coordinating with others over the Web through the use of Java-based agent wrapper techniques. Thirdly, the distributed computing power embedded in the system supports the ability of remote processing. Instead of having all of the computation taking place on a user's local machine, the user sends data, via the console agent, to the distributed system, which returns information that is then displayed on the local machine. Fourthly, the federated approach adopted to model the system ensures openness and dynamics of the system. Users can freely add or remove agents without having to halt or reinitialize the work in progress in any way. Fifthly, the whole system is developed using Java, a platform-independent language, so that the system can run unaltered on all platforms that support Java. A prototype system for product design and planning on machining processes was implemented. This system comprises a Facilitator, a Design Agent, a Manufacturing Capability Agent, a Manufacturability Evaluation Agent, a Process Planning Agent and a Cost Estimation Agent. The performance of the prototype system shows that it could be extended to include other service agents, such as assemblability analysis and scheduling, to become a comprehensive distributed concurrent engineering system for geographically dispersed customers and suppliers.