SummaryIncreasing pressures from a variety of directives and standards have caused manufacturing enterprises to consider and implement energy assessment and energy performance goals-to improve both their economic and their environmental performance. Flexible manufacturing systems (FMSs) pose a challenge for energy management because of their complexity and the difficulty of data collection. FMSs allow manufacturers to adjust to customers' requirements and meet changing demands, which makes it possible for manufacturers to respond quickly to the market. To address this challenge, a practical energy model for machining systems based on colored timed Petri nets (CTPNs) is proposed. In this article, the energy consumption of FMS are first analyzed. Then, an energy model of FMSs based on CTPNs is proposed in which the uncertainty of task assignment and volatility of operation time are treated by Petri net (PN) functions so that data on the consumption of FMSs can be collected automatically. Finally, through the case study of an FMS with two jobs, the proposed energy model is simulated and the simulation results with colored PN tools are shown to be significant in practice.

Increasing pressures from a variety of directives and standards have caused the manufacturing enterprises to consider and initiate implementation of energy assessment and energy quota practices to improve both their economic and environmental performance. Therefore, in view of the complexity of machining system's energy consumption and the difficulty of data collection for energy analysis, a simplified and practical energy consumption model for machining system based on Coloured Petri Net (CPN) was proposed. Firstly, the energy flow of machining system was analysed. And then the energy consumption model of the machining system processing various tasks based on CPN was proposed, where the calculation method of energy use during production was simplified and it was determined by four parameters: idle power of machine, machining time, material pattern, and material removal volume. Finally, through the case study of a machining system with two tasks, the proposed energy model was simulated and the simulation results were proved to be significant in practice.