Study On Skipping Considered In Two-stage Processing And Assembly Flow Shop Scheduling Measures Based On TS-IHVNS

Due to the economic globalization,more and more domestic specialized equipment manufacturers face the challenge of personalizing,diversifying,and customizing clients order requirements.With the in-depth implementation of the Made in China 2025 strategy,more and more enterprises have adopted Intelligent Manufacturing methods and Dedicated flexible tools and fixtures and industrial robots,which based on the Industrial Internet of Things,artificial intelligence algorithms,etc..They upgraded the software and hardware on the production workshop to adapt to the tough international competition.In practical processing,there are often some distinctions in the processing procedure of parts with similar structure.In this regard,manufacturers providing multiple varieties and small batch productions might distribute workpieces with similar process paths to the same assembly line with flexible production capabilities.Distributers distribute parts with similar processing procedures to the dedicated flowshop with flexible processing capacity,then assemble products of deal on other dedicated assembly work station based on the bill of materials of certain procdut,that way,the company can improve its efficiency.Regarding the two-stage assembly line as push-type producing line,the coordinated supply of materials between the two stages is very significant.Therefore,it's important to design and use search algorithms to coordinate the processing stage with skipping attributes and the assembly stage with material constraints to shorten the producing cycle time of products,improve the response speed of the enterprise to the order,customer satisfaction,and reduce the cost of work in progress.Based on the existing flowshop scheduling theory,this paper studies the sub-problems of multi-stage assembly flowshop scheduling problems,including two-stage assembly flowshop scheduling problems,semi-flowshop scheduling problems,non-permutation flowshop problems,and so on.Publishes Two-stage assembly flowshop scheduling problem considering skipping attribution,analyzes the characteristics of the problem,classifies the problem and testing the theory of constraints.Aiming at the optimization goal of minimizing the maximum makespan,the study considering both the processing stage with the skipping characteristics and the assembly stage which need to reduce the waste of idle time.Establishes a mixed integer programming model for this problem,and the validity of the model was verified by Lingo software.Two local search algorithms are proposed to solve the scheduling problems of different scales.Firstly,the two production stages are regarded as two machines,and the Johnson algorithm is used to generate a feasible initial solutions.Then,the heuristic variable neighborhood search algorithm(HVNS)is used to maximize the processing time.In order to evaluate the goal,the permutation solution sequence of the scheduling problem is solved.Based on the HVNS algorithm,an improved variable neighborhood tabu search algorithm is proposed.This algorithm adopts a non-transformation strategy for skipping parts to reduce the solution space,and search for non-permutation solutions which are missed by HVNS.And the neighborhood change rules are dynamically adapting in the search process,so that the results are closer to the optimal solution.Then,the performances of the two algorithms under different problem scales are analyzed on experiments,and the superiority of the improved TS-IHVNS algorithm in solving efficiency and solution quality is verified.Finally,the algorithms proposed in this paper are applied to N Company's manufacturing scheduling,which reduces the products makespan and improves the enterprise's workforce efficiently.