A dynamic flow control policy for failure prone flexible manufacturing systems

A dynamic policy for flow control of flexible manufacturing systems is introduced in the paper. The machines in the system are assumed to be unreliable. In the face of machine failures, the aim of this control method is to minimize the difference between the number of parts produced and the number of parts required at the end of production. The control law is calculated by using successively two linear programs: the first one calculates a lower bound of control law that allows production balancing; the second one maximizes production rates. To take into account machine state changes and to avoid overproduction, the control law is recalculated every time a change in machine state occurs and every time the system reaches the production target of a part type. The proposed method is very easy to use and needs little computation time. Numerical examples show that the proposed method produces good performances when applied to a simulation model of a flexible manufacturing system with failure prone machines