Modelling reconfigurable manufacturing systems with coloured timed Petri nets

International audienceReconfigurable manufacturing systems (RMSs) have been acknowledged as a promising means of providing manufacturing companies with the required production capacities and capabilities. This is accomplished through reconfiguring system elements over time for a diverse set of individualized products often required in small quantities and with short delivery lead times. Recognizing the importance of dynamic modeling and visualization in decision-making support in RMSs and the limitations of current research, we propose in this work to model RMSs with Petri net (PN) techniques focusing on the process of reconfiguring system elements while considering constraints and system performance. In view of the modeling challenges, including variety handling, production variation accommodation, machine selection, and constraint satisfaction, we develop a new formalism of colored timed PNs. In conjunction with colored tokens and timing in colored and timed PNs, we also define a reconfiguration mechanism to meet modeling challenges. An application case from an electronics company producing mobile phone vibration motors is presented. Also reported are system analysis and application results, which show how the proposed formalism can be used in the reconfiguration decision making process

Nested coloured timed Petri nets for production configuration of product families

International audienceProduction configuration is as an effective technique to deal with product variety while maintaining production stability and efficiency. It involves a diverse set of process elements (e.g., machines, operations), a high variety of component parts and assemblies and many constraints arising from product and process variety. Production configuration entails the selection and subsequent arrangement of process elements into complete production processes and the final evaluation of configured multiple alternatives. To better understand production configuration and its implementation, we study the underlying logic for configuring production processes using a dynamic modeling and visualization approach. This is accomplished through developing a new formalism of nested colored timed Petri nets (PNs). In view of the inherent modeling difficulties, in the formalism three types of nets - process nets, assembly nets and manufacturing nets - together with a nested net system are defined. Using an industrial example of vibration motors, we show how the proposed formalism can be applied to specify production processes at different levels of abstraction to achieve production configuration