Two-level optimization method for optimal control of a class of hybrid systems

In this paper, a study on modeling, analysis and optimal control problems for a class of hybrid manufacturing systems is investigated. In this framework, the discrete entities have a state characterized by a temporal component whose evolution is described by event-driven dynamics and a physical component whose evolution is described by continuous time-driven dynamics, thus it is a typical hybrid system. Not only the optimal control for a manufacturing process but also the optimal entrance time for each job´s entry into the production line is considered in this paper. The whole problem is solved by a two-level optimization method: in the inner level, for any given arrival time sequence of the jobs, the optimal control for manufacturing process is considered, which includes the properties of the optimal control as well as solving method etc, while in the outer level, we use an improved evolutionary programming algorithm to decide the optimal entering time to production line for each job. Finally, some examples are given to illustrate the validity of our algorithm.