Optimal Scheduling Method And Its Application For Bell-type Batch Annealing Process

Bell-type batch annealing is one of the important procedures in cold-roll thin sheet production in iron and steel industry. The production scheduling of bell-type batch annealing furnaces is a typical multi-working procedure, re-entry, multi-machine parallel scheduling problem with complicated resource constraints, energy constraints and working procedure constraints. It is very difficult to build the mathematic model of the optimal scheduling of bell-type batch annealing production. The process time of cooling procedure in bell-type batch annealing is unknown when the scheduling begins. It is very important to predict the cooling time of the annealing furnaces, which is the first step to realize the optimal scheduling of the annealing production. Realizing the dynamic scheduling of bell-type batch annealing is also urgent in the cold-roll thin sheet production factory. Aiming at solving these problems and based on review of the related research reference, this dissertation has carried on the following research.A new production scheduling method of bell-type batch annealing based on the simulation-optimization frame is proposed in this dissertation. It is better than the MILP method and Greedily Sorting Method proposed in the correlative references. It accords with the natural structure of bell-type batch annealing production, and can realize the dynamic scheduling of bell-type batch annealing production.The cooling time prediction of the annealing furnaces is a multi-input and single-output process, which is simplified to a group of single-input and single-output prediction problems. The fuzzy C-Means algorithm is used to cluster the production data in batch annealing process, then the exponent least square algorithm is used to form a cooling time prediction method for annealing furnaces. It realizes the cooling time prediction of batch annealing production without new facility investment needed, which paves the way for optimal scheduling and the whole flow simulation of annealing process.A discrete event simulation model of bell-type batch annealing shop is proposed in this dissertation, in which the discrete event simulation technique and object-oriented modeling technique are used. The input of this model is the charging order of the annealing plans being annealed, which can be coded in natural number and expressed as the gene in genetic algorithm conveniently. This model considers all kinds of constraints in the optimal scheduling of bell-type batch annealing production and can give a feasible scheduling corresponding to each charging order the dispatcher gives. An optimal scheduling method of bell-type batch annealing production is proposed by combining an improved genetic algorithm and discrete event simulation technique. The discrete event simulation model of...