Research On The Hull Mixed-model Assembly Welding System Dynamical Scheduling Based On Random Operating Time

Hull curved blocks construction is the key technology to build a moderm shipbuilding enterprise. Hull curved blocks construction directly affect the level of efficiency in shipbuilding. Therefore, there is a great significance to research on the dynamical scheduling of hull curved blocks shop. Virtual flow-line production mode for hull curved block construction is studied in this paper. Based on uncertain processing time of hull curved blocks,combined with possible emergencies in the actual production of hull curved blocks shop, the scheduling optimization problems of hull curved blocks shop were studied.(1 ) Stochastic Petri nets and complexity model based on hull curved blocks construction were established, according to the technological characteristics of hull curved blocks construction. The gray system theory is used to deal with uncertain processing time of hull curved blocks. Combined with Markov chain, through calculating the steady-state probability, the analytical method of hull curved blocks manufacturing shop was introduced.Then based on the complexity of established model, the complexity of shop system was analyzed.(2) A dynamical scheduling model based on efficiency and stability was established to reduce the complexity of hull curved blocks rescheduling. Then corresponding improved rescheduling model was proposed for the possible occurring emergencies. The improved immune clone algorithm is proposed for scheduling optimization. Finally, the effectiveness of algorithm and the superiority of model were demonstrated through comparing and analyzing examples.(3) Considering the characteristics of virtual flow-line production mode for hull curved blocks construction and uncertain processing time, the robust-reactive scheduling strategy is used to reduce the number of rescheduling. Robust scheduling is generated by inserting idle time in static scheduling scheme, to absorb the disturbance caused by uncertain processing time and the possible occurring emergencies in the process of manufacturing. Furthermore reactive scheduling is used to handle the disturbance which cannot be absorbed by robust scheduling. The multi-objective model of hull curved blocks manufacturing shop is established, the improved multi-objective immune clone selection algorithm is used to optimize and analyze combined with examples.The dynamical scheduling system of hull curved blocks shop was developed by using VB 6.0. The prototype system can manage production information of shop and choose the different method to optimize the scheduling arrangements for different scheduling problems,with certain analysis ability for the visual optimization results. Finally, the practicability of prototype system is proved through the specific processing example of hull curved blocks.