Research On Production Sequence Of Mixed-flow Assembly Line Based On Improved Leapfrog Algorithm

In recent years,the automobile industry has been developing rapidly with the improvement of science and technology and the vigorous support of governments at all levels,and people’s consumption concept of automobiles has changed tremendously.While meeting the diversified and personalized needs of customers,the automobile manufacturing industry also has to overcome a series of "stuck neck" problems such as how to improve production efficiency,enhance equipment utilization and reduce inventory costs,so as to improve the ability to respond to market demand and gain a dominant position in the huge market.Mixed flow production has become a major production method in the automotive industry,and a reasonable start-up sequence can improve the productivity of production lines,make full use of existing resources,and achieve smooth production.In this paper,a multi-objective mathematical optimization model is established for the actual requirements of the mixed flow assembly line of Company H’s engine plant,and an improved hybrid frog-jumping algorithm is designed for the optimization of the start-up sequence of the mixed-flow assembly line,which can be used to solve the optimal start-up sequence for the mixed-flow assembly line of Company H’s engine plant,thus reducing the production operation cost and maximizing the assembly efficiency of the mixed-flow assembly line.Firstly,in order to improve the assembly efficiency and reduce the production cost of the mixed-flow assembly line in the engine plant of Company H,this thesis establishes the mathematical model of each optimization objective with the minimum production cycle time,material consumption leveling and minimizing the total adjustment changeover time as the optimization objectives,and finally establishes the multi-objective-based optimization of the mixed-flow assembly line using hierarchical analysis and weighted average method.Finally,a comprehensive mathematical model based on multi-objective optimisation for the start-up sequence of the mixed-flow assembly line was established using hierarchical analysis and weighted average method.Secondly,based on the standard hybrid frog-hopping algorithm,this paper proposes an improved hybrid frog-hopping algorithm based on the optimization problem of engine mixed-flow assembly line scheduling.In the improved hybrid frog-hopping algorithm,by introducing the greedy idea in the initialized frog population,the quality of the hybrid frog hopping algorithm in generating the initial population is improved to ensure the optimization-seeking performance and convergence of the algorithm,so that the frog population can find a better solution in less evolutionary times;the cross-renewal method based on genetic algorithm is used in the local search,which is a good solution to the traditional hybrid frog-hopping algorithm in solving the mixed-flow assembly line production.The problem that the algorithm is close to a random search due to the large number of infeasible solutions in the search process of the sequential optimization example problem is solved by using the genetic algorithm-based cross-renewal method in the local search,which enables other frogs to take over the excellent information fragment of the optimal individual;to improve the way that the hybrid frog-hopping algorithm only updates the worst frog individual,the simulated annealing algorithm is introduced into the global search of the frog population of the hybrid frog-hopping algorithm,and Search around the global optimal frog individual.This expands the search space and ensures that the best frogs will not be lost,also avoids the algorithm to be premature and fall into local optimum.Thirdly,the effectiveness of the improved hybrid frog-jumping algorithm is verified by the example of the engine mixed-flow assembly line.We analyzed the current situation of the engine mixed-flow assembly line of Company H and solved the problem of optimizing the start-up sequence of the mixed-flow assembly line by using the improved hybrid frog-hopping algorithm,hybrid frog-hopping algorithm,and simulated annealing algorithm,and compared the obtained optimal target values and iteration curves.The improved hybrid frog-jumping algorithm is significantly better than the hybrid frog-jumping algorithm and simulated annealing algorithm,which illustrates the superiority and effectiveness of the improved hybrid frog-jumping algorithm in solving this kind of problems,and the improved hybrid frog-jumping algorithm is simulated for the same discrete TSP problem to further verify the performance of the improved hybrid frog-jumping algorithm.Finally,a user-friendly human-machine interface for an engine mixed-flow assembly line scheduling optimization system based on an improved hybrid frog-jumping algorithm was developed using the GUI visual interactive design tool of MATLAB(R2021b)software,in the context of the total assembly plant of Company H’s engine plant,which improving the equipment utilization and the assembly efficiency,also reducing the workload of production planners.