Research On The Scheduling Problem Of Rush Order Based On Discrete Event Dynamic System

With the development of modern manufacturing technology, the dominant party of products changes a lot. The needs of customers present the features of individuation, diversification and customization under the influence of MTO. Combined with increase of unpredictable factors in the market, rush orders frequently appear in the manufacturing enterprise’s production practice, which adds to the test of flexible production capacity. Rush orders usually have the characters of randomness, short delivery date and high profits. In order to improve production efficiency and market competitiveness, most of the enterprises expect to receive more rush orders. However, in front of increase of rush orders, it is difficult for enterprises to develop a reasonable production plan. Thus rush order related scheduling problem is becoming a current research hotspot.The rush order problems that appear in pipeline manufacturing enterprises has been studied in this thesis. By analyzing the characteristics of orders, the modeling of rush order inserting and control method for DEDS are proposed. The problem of rush order inserting is modeled by making use of formal language/automaton. The main work is summarized as follows.(1) The scheduling method of order inserting based on order exited is studied. Considering the characteristics of order inserting based on order exited and orders, minimizing the machine idle time is proposed as the optimization goal. The automaton model is established with the design of controller and determination of time. Last, the effectiveness of this method is verified by an example.(2) The scheduling method of order inserting based on order postponed is researched. With analyzing of characteristics of order inserting and orders, rush orders can be processed by making use of this method. The position of order inserting and regular order postponed are determined by application of forecasting function of time update. Then with determination of start processing time of all the sorting orders, the sorted set of all the orders is obtained. Finally, the calculation of machine idle time is given and the optimal sorting is got. The effectiveness of this method is verified by an instance.(3) The scheduling method of order inserting based on order rearranged is put forward. This method can be applied to emergency process of rush order with priority. Then with application of forecasting function of time update and the controller, efficient solution set is acquired. Besides, the final scheduling scheme is determined via the calculation of machine idle time. Eventually, the feasibility of this method is illustrated by a case.Three methods of rush order problem are proposed in this thesis. The perfect results and reasonable production plan can be obtained by analyzation of these ways. Undoubtedly, it is good for enterprises to deal with foreign paroxysmal rush orders and improvement of production capacity. So these methods will have more superior guiding significance and practical value.