An integrated environment for the design and control of deadlock-free flexible manufacturing cells

At the enterprise level, manufacturing organizations are faced with accelerating technological cycles, global competition and an increasingly mobile work force. The flexibility of the enterprise and its ability to respond to various customer demands governs the competitiveness of the enterprise to the changes in its market and in the society in which it operates. It has been recognized for many years that flexibility on the enterprise floor can always be achieved if the resulting cost of product and process changeovers and its operations are not considered. However, with the increasing competitive pressures on today's manufacturing enterprise, a flexible-manufacturing environment must be achieved at relatively low cost and high work-force productivity while maintaining a competitive advantage. To accomplish this goal, the manufacturing enterprise must be able to be reconfigured and verified with an increased level of automation that is scalable and flexible to meet diverse product demands quickly and economically. In this paper, we will introduce the recent research work on developing an integrated rapid prototyping environment, EMBench [22, 23], which can provide design, control configuration, simulation and deployment services for flexible manufacturing systems. This rapid prototyping environment has its own user-friendly GUI (Graphical User Interlace) that allows user to issue various commands to the controller at different layers, from the simple joint servo to the complex manufacturing cell. In this paper, we also propose the implementation diagram for the controller of manufacturing cells that consists of scheduler, dispatcher, real-time database and structural control policy. All these internal components are responsible for storing system configuration, optimizing processing plan, releasing appropriate command, etc. We also present the idea of cell model and explore its characteristics and behaviors as well as the resource and workstation models. All above modules and architecture are developed using IEC-61499 function blocks that support scalable expansion and modular design. To demonstrate our theoretical achievements, we have developed various IEC-61499 function blocks to integrate various resources on the enterprise shop floor and achieve flexibility at a low cost. This software environment facilitates a modular, component-based mechanical and control design, simulating and prototyping tool for shop floor control.