A Synchronization Mechanism with Shared Storage Model for Distributed Manufacturing Simulation Systems

Simulators play important roles in the designing of new acturing systems. As manufacturing systems are being created on larger and more complicated scales than ever before, it is increasingly necessary to have opportunities for several persons to design a manufacturing system concurrently. In this case, the designers often use suitable discrete event simulators to evaluate their assigned subsystems. After the subsystems are evaluated, it is necessary to evaluate the full system. To do this, the designers need to make the manufacturing system model by synchronizing several different simulators. In such distributed simulation systems using discrete event simulators, it is important to manage a distributed simulation clock and each simulator clock as well as to define interfaces among the simulation models. With the simulation clock, it is often necessary to perform rollbacks. The rollback function returns the simulation clock to a past time in order to synchronize events among the simulations. However, most commercially available simulators do not include the rollback function. The purpose of this research is to develop a distributed simulation synchronization method that includes a function for managing distributed simulation clocks without the rollback function and for managing interfaces among simulation models. In this paper, we propose a storage model concept as the method. We develop an algorithm to implement the proposed concept, and we develop a distributed simulation system configuration using HLA. A case study is then carried out to evaluate the performance of the cooperative work.