The look ahead dispatching procedure

The look ahead dispatching procedure is an approximation method for solving the minimum makespan problem for job shops with routing flexibility. It is a dispatching procedure in the sense that each run of the procedure results in a specification of only one next operation for every machine in the system. The selection of these opeations is based on a limited search in the space of possible states the system can reach within approximately twice the average cycle time. This search uses a newly developed representation of the state space, and a newly developed evaluation function. The results are considerably better than those obtained with ordinary priority dispatching rules. The last section of the paper discusses how this procedure can be used for the real time control of Flexible Manufacturing Systems.