Simulation-based hybrid control research on WIP in a multi-tightly-coupled-cells production system

This paper studies Work-In-Process (WIP) inventory problems in a multi-tightly-coupled-cells production system. Through an analysis of an AS-IS simulation model, ineffective control of tightly coupled cells cause serious system bottlenecks, higher WIP inventory levels and longer cycle times. Aiming to resolve these problems, a hybrid control method and a corresponding centralized hybrid controller are developed. This optimized method is used to monitor the changes in WIP and improve WIP control by integrating the Pull and Push modes. In a TO-BE simulation model, the centralized hybrid controller is embedded to execute this optimized control idea. The model is explored with a control objective to maintain the WIP inventory and cycle times at low levels by dynamically regulating the processing rate of distributed workstations. The simulation results demonstrate that this optimized method avoids system instability and eliminates bottlenecks. By comparison, the proposed approach significantly improves the system´s performance, rapid response and robustness.