Research On Dynamic Scheduling Of Continuous Process

Nowadays, modern industries are facing severe challenges, that complex and changeable processes make the traditional methods of production cannot meet the highly competitive social environment. Moreover, the production cycle is getting shorter while consumers become increasingly high demanding for the requirements of the diversification and punctual delivery of products. Therefore, higher requirements for production scheduling have been put forward. The modern enterprises should not only formulate the best scheduling plan, but also make quick reaction to all types of unexpected events that occur in the production process to ensure the continuous production, so as to get the maximum economic benefits. Thus, it is essential to make production scheduling, especially the scheduling to the unexpected events in the production process.In the modern industries, the continuous process is widely used. And in the continuous production process, the production environment is often unstable and there are many uncertainties. This paper focuses on how to quickly respond to unexpected events in the production process to ensure the continuous production. Dynamic scheduling problem for the uncertain environment of continuous process is researched, the reactive scheduling method based on a scheduling range is proposed, and the reactive scheduling model is build. This paper also makes a simulation study of fast moving consumer goods manufacturing, and the results verify the effectiveness of the method.The contributions are summarized as follows:Firstly, based on the analysis of the background and significance of the continuous process scheduling, some problems in the continuous process of production scheduling are found. By summing up the research status of the continuous process scheduling and dynamic scheduling, the advantages and disadvantages of various research methods have been analyzed, and finally the approach reactive scheduling which is suitable for dealing with unexpected events is sellected.Secondly, based on learning the description of the production process methods and mathematical programming modeling approach, the unit-specific event-based continuous-time modeling method is chosen. The fast moving consumer goods manufacturing processes is selected as simulation example, a detailed analysis of the fast moving consumer goods manufacturing processes and production process of various storage strategies is given.Thirdly, a detailed analysis of the impact on the production scheduling of unit breakdown in the continuous production process is given. Predictive-reactive scheduling method is used to build a reactive scheduling workflow, a method in the form of an establishment of a fixed task list to determine the scheduling range and the reactive scheduling model based on the scheduling range are presented. By determining the scheduling range, tasks which are finished before the unit shutdown or ongoing but un-relevant with the shutdown unit are fixed. Reactive scheduling model contains the information of fixed task list, so that these tasks in the new scheduling scheme are consistent with the initial scheduling scheme. Reactive scheduling model for unit shutdown is proposed, and the effectiveness of the method is proved by the simulation of the fast moving consumer goods manufacturing.Finally, another kind of unexpected event in the continuous process is researched. Regarding to the new or modified orders in the production process, a reactive scheduling method dealing with those unexpected events is proposed, a production scheduling process is designed and reactive scheduling model for the change orders is presented. Fast moving consumer goods manufacturing process simulation verifys the validity of the method.The article ended with a summary of the full text, pointed out the advantages and disadvantages of this paper, and put forward the issues which need solving in the future.