Digital twin for energy-efficient integrated process planning and scheduling

With the enhancement of environmental protection awareness, energy-efficient scheduling has attracted widespread attention. But little consideration is given to process flexibility in the production process. In fact, the integrated process planning and scheduling (IPPS) can further reduce energy consumption. Interference events often occur in production workshops, such as machine failures and new jobs arrival, which affect production operation. Therefore, a new energy-efficient IPPS (EIPPS) method based on digital twin (DT) is proposed in this paper. Firstly, the DT-based EIPPS framework of the intelligent workshop is introduced. Next, an event-based real-time mapping method is proposed to solve the problem of a low degree of virtual-real mapping. Interference events can also be quickly identified. Then, a dynamic EIPPS strategy is proposed to respond to interference events in time. In this strategy, game theory is used to reduce makespan and energy consumption. Finally, a prototype system is designed to verify the effectiveness of the proposed dynamic EIPPS strategy.