Research On Production Scheduling Method Of Marine Diesel Engine Assembly Workshop Based On Digital Twin

With the rapid development of intelligent manufacturing,the Internet of Things,cloud computing and other new generation information technologies are widely used in marine diesel engine assembly workshops,promoting the development of marine diesel engine assembly workshops in the direction of informatization.Driven by intelligent manufacturing,the drawbacks of the production scheduling mode of traditional marine diesel engine assembly workshops are becoming increasingly obvious.Aiming at the problems of poor realtime data,insufficient monitoring of production status and frequent abnormal disturbances in the production scheduling process of marine diesel engine assembly workshop,this thesis combines digital twin technology to carry out the research on production scheduling method of marine diesel engine assembly workshop based on digital twin,and the main research contents are as follows:(1)Aiming at the problem that it is difficult to realize real-time monitoring of workshop production status and rapid response to disturbance events under the existing scheduling mode,this thesis combines digital twin technology to construct a production scheduling framework for marine diesel engine assembly workshops based on digital twin,and elaborates on the components of the production scheduling framework and the key technologies involved.(2)In order to generate a reasonable and efficient initial scheduling scheme,the production scheduling problem of marine diesel engine assembly workshop is described and analyzed,and a mathematical model is constructed to minimize the maximum completion time,minimize the maximum load of the assembly team and minimize the total assembly cost.Aiming at the shortcomings that the traditional NSGA-Ⅱ algorithm is easy to fall into local optimum,the idea of variable neighborhood search is integrated into the solution process of the NSGA-Ⅱ algorithm,and three neighborhood structures are designed for variable neighborhood search,which effectively improves the local search ability of the traditional NSGA-Ⅱ algorithm.Finally,taking the actual assembly operation in the pre-assembly station of the marine diesel engine assembly workshop as an example,the NSGA-Ⅱ algorithm of mixed variable neighborhood search is verified to have better convergence and diversity.(3)In view of the frequent occurrence of abnormal disturbance events in the workshop,insufficient monitoring of production status,etc.,which cause the production process to deviate from the initial scheduling scheme and cannot respond quickly to disturbance events,this thesis proposes a production scheduling operation mechanism of marine diesel engine assembly workshop based on digital twin.On this basis,the specific disturbance events of worker absence and assembly equipment failure in the assembly team are analyzed,and a combined rescheduling strategy is designed,that is,the right-shift rescheduling strategy and the complete rescheduling strategy are used to generate the rescheduling scheme,and the maximum completion time and process deviation after minimizing the rescheduling are used as the rescheduling performance evaluation indicators to select the rescheduling scheme,and finally the effectiveness of this method is verified by simulation through examples.(4)Based on the analysis of the production scheduling needs of the marine diesel engine assembly workshop and the related technical research in the above chapters,the overall architecture and functional modules of the production scheduling system are designed,and finally a production scheduling system including production order management,production task management,initial scheduling,dynamic scheduling,virtual workshop scene display and other functions is built.