A method of flexible scheduling for flexible manufacturing systems

This paper presents a scheduling method for flexible manufacturing systems (FMSs) by introducing concept of scheduling flexibility. Production sequence and available slack at start time are determined for operations of part types to be processed in an FMS. The flexibility of scheduling is defined as the weighted sum of the available slack of each machine. The available slack consists of slack time for starting operation on the machine and the sum of ideal times of the machine after scheduled. The objectives of scheduling are to minimize the maximum tardiness of completing part types and to maximize the weighted available slack of machines. The branch-and-bound method is applied and an optimization algorithm is developed to solve the scheduling problem. A numerical example illustrates the validity and feasibility of the proposed algorithm.