Distributed control systems (DCSs) consisting of a plant, a controller composed of many devices, and an open network interconnecting devices, are now used in many automation areas. For assuring the control performance under the heavy traffic on the network, the simulation of DCS is strongly needed. In the case of DCSs for controlling a mechanical plant, the graphical and cooperative simulation between the controller model and the plant model becomes important to verify the sequence of motions of the plant. For this purpose, we propose a systematic object-oriented-based DCS modeling procedure to efficiently and uniformly develop the DCS simulation model. From this procedure, we can describe the formal description of DCS simulation model based on five object-oriented design patterns which describe the structure and behavior of the DCS. We also propose an event chain mechanism between the statechart-based controller model and the graphical plant model. Finally, the cooperative DCS simulation software is developed by using the Java 3D API.

An open distributed control system (DCS), which consists of a large number of devices and a single open network interconnecting those devices, is now used in many automation areas. One critical problem of the DCS, however, is that because there is massive traffic on the network, the system integrator must carefully tune the network traffic after the construction of the system to assure its control performance. Hence, a DCS simulator is strongly needed. In our study, we propose an object-oriented design pattern approach as a uniform, rapid and accurate method of modeling and simulating a DCS. Two special design patterns are proposed: the Statechart pattern which defines classes and the state-transition execution mechanism for realizing the dynamic behavior of devices; and the device-constructor pattern which defines classes and their instantiation mechanism for realizing the structure of devices composed of many kinds of sensors and actuators. The systematic procedures from those patterns to the executable Java code of the simulation model are also discussed. Furthermore, the effectiveness of our approach was investigated through actually developing an in-house Java-based DCS simulator.

An open distributed control system (DCS), which consists of many devices and an open network interconnecting them, is now used in many automation areas. For assuring control performance under heavy traffic on the network, simulation of a DCS is required. For this purpose, we propose an object-oriented design pattern approach as a uniform, efficient and accurate method of modeling and simulating a DCS. Four design patterns are proposed. Device constructor and composite-device-constructor patterns describe classes and mechanisms for uniformly structuring device models composed of many kinds of sensors and actuators. A statechart pattern defines classes and the state-transition execution mechanism for realizing the behavior of sensors and actuators in a device. The event-chain pattern defines classes and the event dispatching mechanism among sensors and actuators in both an intra-device and inter-device manner. The systematic implementation procedures from these patterns to the executable Java code of the DCS simulation model are also discussed. Finally the effectiveness of our approach was proved by developing the Java-based DCS modeler and simulator used in building automation.

A seamless design methodology for developing manufacturing cell control software is proposed. The methodology is based both on the graphical specification and on the systematic design procedure of its conversion to the control code. The graphical specification describes the component configuration of the cell and the activity sequence on which the devices should act. An object diagram and an activity-control-condition diagram are introduced for this purpose. The systematic design procedure specifies a clearly-defined conversion from the initial graphical specification to the cell control software code. The conversion consists of three processes: refinement, translation and information. A diagram editor has also been developed to help the programmer carry out this design procedure. Finally, the functionality of the control software generated by using the proposed methodology is validated through co-simulation with a Petri net simulator.