The Key Technologies Of Job Shop Scheduling Under Mixed Production

For the problem of job shop scheduling under the mixed production(processing and assembly),the paper has taken the background of mixed assembly line enterprise or operation assembly mode enterprises which mainly carries on small batch production in the machinery manufacturing, and has balanced the requirements of the pursuit of economic benefit for management and the production efficiency for production management considering the producing scheduling as the management pattern of complexity of producing organization in the producing process and the loss the parts.For the job shop scheduling research under mixed production patterns, the traditional production scheduling corresponds to the research of the independent processing stage or the assembly stage, which has ignored the inherent parallelism of processing operation and assembly operations. The paper has taken the background of the second workshop in Dalian Locomotive and Rolling Stock Co., Ltd. It has mainly do some research on MOJSSP more-orders job shop scheduling problem (MOJSSP) and multi-object scheduling, and Implemented the integrated shop scheduling on the processing and assembly stage. The paper has provided the scientific basis for the shop management of mixed production patterns, the research result can be applied to the construction of enterprise information, which can provide effective production planning data for corporate decision-making as well as guide the workshop production and product sales. It makes an important sense in the project, and there is a broad market demand. The main research includes:(1) Firstly, the paper has introduced the research background and the meaning. On the basis of scheduling technology under mixed production form, it has summarized the characteristics of job shop under mixed production form, and the conflict of "processing and assembly", and it has summarized the unsolved problems of scheduling.(2) For the problem of multi-object scheduling, in front of different deadlines, aiming at the maximum scheduling of weighted order, integer programming model is used for modeling to solve the problems of MOJSSP under the mixed production pattern, and has provided the MOJSSP resource constraint condition under mixed production pattern in common job shop.(3) For the MOJSSP under mixed production pattern, various elements related to job shop production have been completely considered, such as equipment utilization, work piece job completion time, preparation time of pre-process, inter-process handling time, storage costs, labor costs, etc. Various elements affecting the operation plan have been determined, then, we begin to carry on multi-objective scheduling modeling for various price indexes.(4) The traditional scheduling methods are difficult to solve the job scheduling problems under mixed production pattern from a comprehensive perspective. In the paper, framework of ant colony algorithm to solve the scheduling problem under the mixed production pattern has been provided. The former has designed a new genetic algorithm encoding method which can determine the only assembly location in the product structure; the latter has designed progressive ant window structure to accurately describe the assembly constraints, which can reasonably update the path pheromone according to completion of objects by a kind of update strategy which is based on the order pheromone. The paper uses the international benchmarks constructed test data to carry on test, which has proved the effectiveness of the framework, and it has summarized the characteristics to solve the problem and applications by using the two algorithm framework.(5) The multi-objective scheduling algorithm which is based on genetic algorithm has been proposed to solve the multi-object scheduling problems under mixed production pattern. The frame carries on encoding method by using the previous encoding method, which has taken the minimum costs and scheduling time as the target, after the scheduling tasks have been determined and intensive production has been calculated, and the Pareto solution set has provided the scheduling planning. Through the production data simulation in some locomotive factory, the algorithm framework has been calculated into the basic genetic algorithm, it has been proved that the algorithm is effective.(6) The paper has provided the non-uniform ACO (ant colony optimization) oriented to job shop and an improved multi-generation algorithm has been provided. The experiment has showed that, the former has increased the convergence rate of ant colony in solving the scheduling problem, and the latter has improved the shortcomings of prematurity of algorithm.From the research of the paper, the scheduling problems of multi-object scheduling and multi-objective problem under mixed production pattern in job shop can be effectively solved. The research result can make the processing and assembly operations work in parallel, and solve the problem of loss of assembly, as well as reduce the manufacturing quantity and the producing cost. The above research has enriched the workshop scheduling theory under mixed production pattern to some degree.