Research On Rescheduling Driving Mechanism In Job Shop Under Uncertainty

In existing researches about rescheduling driving mechanism, the periodicrescheduling, the event-driven rescheduling and the combination of the both above had a avariety of applications in job shop. However, the driving mechanism is lack of emergencyability to sudden event and is weak in coupling relation with real real-time condition; theevent-driven rescheduling may easily cause huge computational complexity and increaserescheduling frequency so as to induce system shaking; while the combination reschedulingis hard to coordinate the relationship between the periodic rescheduling and theevent-driven rescheduling. So this dissertation analyzes the rescheduling drivingmechanism in job shop under uncertainty for enterprise profit maximization, in order toincrease the stability of the scheduling system as well as the coupling between real-timecondition and scheduling system.Firstly, analyze and classify the uncertain factors during manufacturing and measuringthe disturbing degree of scheduling system based on the combination of fuzzy mathematicsand RBF neural network. Then the measurement of the rescheduling executive cost can beachieved by calculating the time offset cost of comprehensive weighted same process, thetime offset cost of adjacent processes of same process, the time offset cost of activemachine and waiting time offset cost. Based on the above, the pre-scheduling loss functioncan be constituted, and based on optimization objective of rescheduling, the pre-schedulingprofit function can be constituted; then to build the profit-loss model. At last, according tothe quantitative analysis of the profit-loss model, determine the rescheduling drivingmechanism based on fuzzy logic and identify the optimum decision point in order to filterthe unnecessary rescheduling, which can avoid the system shaking due to frequentrescheduling and decrease the loss due to various uncertain changes during manufacturing,so as to ensure the validity and stability of scheduling system.