Dynamic Availability Analysis for the Flexible Manufacturing System Based on a Two-Step Stochastic Model

The paper proposes a dynamic availability analysis approach for the flexible manufacturing system (FMS) under a stochastic environment that machines’ failure and starvation or blockage of production process occur randomly. Accurately knowing the availability of the FMS, which is changing dynamically overtime in a stochastic circumstance could benefit a lot for the improvement or re-design of the system. A two-step stochastic model proposed in current paper that integrates the intermediate buffers into associated workstations equivalently in terms of the relationships between upstream and downstream production rates. Calculation procedures of relevant dynamic availability are established by using the Lz -transform method, which conquer the states-explosion problem which is common in FMS performance analysis. Meanwhile, the impacts of intermediate buffers on the FMS dynamic availability also revealed, which assist to determine the appropriate volumes of the buffers to satisfy the various FMS production demands. A numerical example is presented for illustrating the effectiveness and rationality of the approach.