Research On Joint Decision-making Of Production Scheduling And Condition Based Maintenance

Production scheduling and equipment maintenance are the two important links in the production process of manufacturing enterprises.In the traditional production research,the enterprise often makes decisions independently in these two parts.However,in the actual production process,maintenance planning and production scheduling are interdependent with each other,which affect and restrict each other.The decision that combines these two parts has been developed into the focus of production field.With the rapid development of computer technology and sensor technology,there are more and more device which can detect its degradation state directly or indirectly while processing.Aiming at those repairable devices,the decision that combines production scheduling and maintenance planning has become the important research direction to improve production efficiency and reducing production cost for enterprises.On the basis of actual production scheduling,the research of combination in production scheduling and maintenance planning were carried out by this paper.First,the repairable single-device production system with detectable status is taken as the leading research of the complex multi-device production system.A joint strategy of stand-alone scheduling and non-perfect preventive condition-based maintenance is proposed.A joint decision-making model is established with job scheduling sequence and condition-based preventive maintenance threshold as the decision variables and the minimum total weighted expected completion time as the optimization goal.The corresponding probability density function is derived and solved using numerical methods.First of all,the production system of repairable device with detectable status were selected as the leading research of complex multi equipment production system.The single machine scheduling and imperfect preventive situation which will be made maintenance according to its actual situation were put forward as the decision of combination.The production scheduling sequence and preventive maintenance threshold value were selected as the decision variable,taking the minimum total weighted expected completion time as the purpose of optimization,the model of decision of combination was established to deduce the corresponding probability density function and to solve the problems by using the numerical method.Secondly,aiming at the multi-devices production system with state detectability,their degradation process was analyzed to establish the corresponding stochastic degradation model.The decision of combination in flexible production scheduling and preventive maintenance were put forward,taking the 0-1 of multi-devices and preventive maintenance as decision variables,and the minimization of maximum expected completion time as the goal to establish the model of decision of combination in flexible production scheduling and preventive maintenance.Through numerical analysis,the optimization results under different operation scale and different equipment scale are compared,and the validity of the model was verified;In the process of decision of combination,the preventive maintenance and the optimal value obtained by adopting timebased preventive maintenance strategy were compared to certify the advantage of adopting situation based preventive maintenance strategy in decision of combination.Finally,XX manufacturing workshop of Taiyuan was selected as research object,the decision of combination in production scheduling and situation based preventive maintenance were adopted to make the decision.Compared with the optimal target value of the independent decision,the effectiveness of the decision of combination in practical production was verified.