Research On Production Scheduling Method Of Automobile Chassis Parts

Shop scheduling is to make use of limited resources to arrange the time of the workpieces,and to optimize one or more performance indicators under the constraints.Automobile chassis parts production workshop is an important part of automobile manufacturing enterprises.Under the multispecies and small batch production mode,it has the characteristics of a wide variety of raw materials and parts,limited equipment resources and in-process buffers.In view of the unreasonable allocation of workshop resources,low sorting efficiency and large occupancy space,the production scheduling method of automobile chassis parts is studied,which can effectively reduce processing costs and improve production efficiency.In response to the above problems,the main research contents are as follows:Firstly,the matching problem between raw materials and machine tools is studied.The production status of automobile chassis parts workshop is analyzed.To solve the problem of unreasonable resource allocation in workshop,a material scheduling model is established with the constraint of crane resources and the optimization objective of minimizing machine waiting time.The emulational results of practical data show that the model can effectively solve the problem of machine tool work being held up for lack of materials caused by the layout and limited number of cranes,thus shortening the waiting time of machine tools.Secondly,the processing sequence of parts on machine tools is studied.Aiming at the problems of various parts and low sorting efficiency,the concept of slack time of components and multi-objective workpiece scheduling problem based on complete set rate of components are proposed.Taking the results of material scheduling as input,the workpiece scheduling model is established with the objective functions of minimizing the slack time of components and the number of component delay.The improved non-dominated sorting genetic algorithm is used as the framework to design the model solving algorithm.The coding method of multi-layer chromosomes is designed to express the multiple information of parts.In order to solve the problem of insufficient chromosome crossover,a piecewise linear order crossing method is designed.The results show that the method of scheduling can shorten the slack time of components and improve the sorting efficiency.Thirdly,the rescheduling problem after dynamic event perturbation is studied.A driving mechanism based on the degree of rescheduling requirements is proposed to determine whether the rescheduling is performed after the disturbance occurs.A hierarchical rescheduling strategy based on complete rescheduling is proposed for the characteristics that multiple parts on the same raw material must be processed continuously.Taking the two dynamic event disturbances that includes the failure of machine tools and emergency insert as an example,the rescheduling of chassis parts production is carried out.The results show the effectiveness and feasibility of the proposed driving mechanism and rescheduling strategy.Finally,a scheduling system of automobile chassis parts is studied.On the basis of the research results,the production scheduling system of automobile chassis parts is established by using Plant Simulation,and the production scheduling scheme of parts is obtained by inputting the order production data.The scheduling scheme is simulated by the established visual simulation model,which can output the utilization rate of machines and the working status information of the crane,and provide the basis for scheduling decision.