Study On Integrated Flexible Scheduling With Deferred Constraint

There is a problem in study of integrated flexible scheduling currently, which is that these studies just consider situation that there is sequential constraint among workpieces, but ignore situation that there is deferred constraint among workpieces. In fact, there is deferred constraint problem in practical production. If it is ignored, the manufacturing plan will not be accurate or even be impracticable. So it is necessary to study on the problem with deferred constraint in integrated flexible scheduling.Aiming at the problem of inaccurate scheduling result which leaded by integrated flexible scheduling with device-independence deferred constraint, this paper proposes integrated flexible scheduling algorithm with device-independence deferred constraint. First, through integrated flexible scheduling model with deferred constraint presented, it converts device-independence deferred constraint procedure into sequential constraint procedure, then converts flexible process problem with device-independence deferred constraint into general flexible process problem. Second, for standard procedures which are on same length path and processed on same machine in scheduling process, scheduling short pre-path strategy is proposed to select procedures.For problem that ignoring device-dependence deferred constraint can effect on scheduling result in integrated scheduling process, integrated flexible scheduling algorithm with device-dependence deferred constraint is proposed. This algorithm proposes converting waiting deferred time into device-dependence deferred constraint procedure strategy which is based on concepts of standard procedure, device-dependence deferred procedure and process tree with device-dependence deferred constraint. The scheduling problem with device-dependence deferred constraint can be converted into general integrated flexible scheduling problem which can be resolved easily. Furthermore, it proposes device-dependence deferred procedure adapting adjustment strategy to make procedures which are influenced by device-dependence deferred procedures be processed as early as possible.For problem that there are device-independence deferred constraint and device-dependence deferred constraint simultaneously in integrated flexible scheduling problem, this paper proposes integrated flexible scheduling algorithm with deferred constraint. This algorithm adopts converting device-independence deferred constraint to device-independence deferred procedure strategy to convert flexible process problem with device-independence deferred constraint to general flexible process problem firstly. Then for problem that there is device-dependence deferred constraint among procedures in practical scheduling process, it adopts converting device-dependence deferred constraint to device-dependence deferred procedure to convert integrated scheduling with device-dependence deferred constraint to general flexible scheduling which is easy to resolve.Aiming at integrated flexible scheduling problem with device-independence deferred constraint and device-dependence deferred constraint, this paper proposes corresponding algorithm. Through analyzing algorithm and validating example, the algorithm complexity of this algorithm is famous, and the effectiveness is better. So, this algorithm has theoretical and practical value to a certain extent.