Study On Multistage Adaptive Scheduling Of Job Shop Under Disturbing Environment

Nowadays,the problem that machining enterprises generally face is that the order demand belongs to small and medium-sized batch,and the scheduling of workshop is a key link of enterprise competitiveness.Choosing job shop as the research object,the actual production process disturbance environment faces many random and uncertain disturbance events,such as emergency single,change of machine failure,the date of delivery,the high frequency disturbance can lead to serious interference machining workshop of steady operation,this puts forward higher requirements on production scheduling management.A reasonable scheduling scheme can guide production better and provide a good reference scheme for enterprises to optimize the comprehensive production capacity of the workshop.Furthermore,it can also improve the overall efficiency.Therefore,in this paper,to achieve robust jobs in the disturbing environment,job shop scheduling decisions are made according to the influence of various factors in the disturbing environment.The main research contents are as follows:First of all,we do a general analysis to production scheduling disturbance and facing the perturbation of the current strategy,and then mainly discuss the classification of perturbation in the process of the production process and analysis the effects of production,determine the disturbance processing time indicators for evaluating indicator of production scheduling system in the disturbance environment disturbance,and a quantitative description with utility theory,the perturbation influence of hierarchies,forge multi-stage adaptive scheduling strategy based on processing time technical route,namely the time buffer method of scheduling strategy and consider processing time deviation degree evaluation of online scheduling policy,providing theoretical background knowledge and technical research route for the next two chapters.Secondly,in combination with the time buffer method of technical route based on scheduling strategy,robustness to make maximization as the objective function,according to the characteristics of job shop and the related constraint conditions to establish the scheduling model based on genetic tabu algorithm,using buffer insertion time before processing activity scheduling strategy,combining processing start time and time limit for a project by the size of the buffer time is calculated.A special genetic and tabu search algorithm was designed to solve the problem.Finally,an example data of an enterprise workshop was used for experimental simulation.Finally,the job shop online scheduling problem is further studied for processing time disturbance.Different from the above studies,the scheduling here occurs in the production process,and the online scheduling model is established based on the improved ant colony algorithm.The tolerance of processing time deviation was designed to filter redundancy scheduling,and the event and cyclehybrid driving mechanism was used to develop automatic triggering rolling strategy.Deviation from the experimental simulation to determine the tolerance value and best cycle driven rolling window step length,redefining the ant algorithm and state transition rules,then the basic genetic algorithm and comparing with the results and the standard genetic algorithm,the experiment proved the feasibility of online scheduling scheme,the results show that the algorithm is shorter,the calculation results has a better quality.