Research On Multi-objective Production Scheduling Method For Assembled Building Products

With the rapid development of China’s assembly construction model,the production of prefabricated parts has become an important part of the construction of assembly buildings,and the demand for prefabricated parts for assembly buildings has increased with its high efficiency,environmental protection and sustainable features,and the product development and delivery cycle has been shortened.Since the production of prefabricated parts has order-oriented characteristics and the products have different sizes,enterprises gradually change their production methods to customized multi-species and small batch in order to improve market competitiveness.Under this production method,production scheduling and resource allocation in the workshop are more complicated.Most of the production scheduling of assembled building products is still done manually through the experience of managers,which leads to low equipment utilization and high production cost.In today’s competitive environment of "time is profit",a scientific and reasonable scheduling plan can effectively reduce production costs and improve production efficiency,thus enhancing the market competitiveness of enterprises.Therefore,it is of great theoretical value and practical significance to optimize the production scheduling of mixed flow shop.In this paper,the multi-objective scheduling problem of mixed flow shop based on the size constraint of mold table is studied in conjunction with the actual situation of prefabricated parts production shop of assembled building products.Firstly,in view of the problems of low utilization rate of die table and low production efficiency in the automated production shop of precast production line,the scheduling of multi-stage production system with parallel stations is studied,and the group batch processing of workpieces based on the die table size constraint is considered,and the mathematical model with the optimization objectives of minimizing the maximum completion time and equipment load balance is established.Secondly,the production scheduling of multi-stage hybrid flow shop with parallel stations is a typical NP-hard problem due to its computational complexity,multi-objective nature and multiple constraints.To solve this problem,this paper proposes genetic algorithm as a global optimization algorithm,using the advantages of concise,easy-to-implement and efficient rules of basic genetic algorithm,combined with the reproduction and diffusion ability of invasive weed algorithm for optimization improvement,and then improve the performance of the algorithm,and use the test function to verify the convergence,solution accuracy and global search ability,and the optimization effect is improved.Finally,taking Yatai precast production line as the research background,the hybrid genetic weed algorithm program is written and debugged on Matlab,and the production group batch sorting obtained by the optimization-seeking calculation takes less time than the original sorting method of the enterprise,and the simulation verification of the die table utilization rate is carried out by Flexsim,which solves the problem of low utilization rate of the die table and low production efficiency in the automated production plant of the precast production line It solves the problem of low productivity and low utilization rate of precast production line.