Study On Algorithm Of Single Piece And Small Batch Shop Scheduling And Rescheduling

Single piece and small batch production is one of the the typical production mode of large-scale discrete manufacturing industry, such as large ships manufacturing, power plant equipment manufacturing, oil refining chemical industry equipment manufacturing, aircraft manufacturing and so on. Most of these enterprise products are produced in build-to-order mode, production conditions often change and a wide range of products, that yield may be one or few quantities. Due to the constraints of large scale equipment and complex technological process, resulting in lower continuity of production in the production process, which makes the study of single piece and small batch production scheduling become more and more important.Based on the analysis of ant colony algorithm for solving job shop scheduling problems, considering the algorithm complexity of the traditional ant colony algorithm uses disjunctive graph to describe the relationship of workpiece,proposed an optimized generalized ant colony algorithm for single piece and small batch shop scheduling problem. The algorithm will select the shortest path way to solve job shop scheduling problem, considering both the workpiece and equipment constraints, the pheromone mechanism is applied to solving the scheduling problem. According to ant colony algorithm state transition rules, the parameters in the formula are studied and improved. The simulation data shows that the generalized ant colony algorithm is not only an effective solution to solve single piece and small batch shop scheduling problem at the same time, it also get the better search results. By comparing with other algorithms in the literature, to verify the generalized ant colony algorithm is better than the traditional in the calculation of the optimal solution and convergence speed.When environment occurred uncertain disturbance event in the actual production, due to the lack of fast and effective rescheduling mechanism driven,resulting in actual production results and plans have significant deviation, that will bring serious consequences to the production process. A new rescheduling algorithm based on the minimized changes of system as optimized goal. Using partial rescheduling method and event driven strategies on the analysis of machine fault disturbance events in production, combined with generalized ant colony algorithm for pre-scheduling scheme. Under bidirectional constrains between equipment and procedures, make full use of the idle time of equipment,which shortens the scheduling deviation effectively, not only improves the continuity of the workpiece, but also reduces the frequency of rescheduling.Actual production calculation verifies the effectiveness of the proposed strategy.Finally compared with the right shift rescheduling method, proved that the the rescheduling strategy for large-scale scheduling problem has better improving effect.By studying on algorithm of single piece and small batch shop scheduling and rescheduling, achieving the closed-loop control of job shop planning and scheduling, which improves the robustness and stability of production workshop.