A new method of sequential control has been developed in order to increase the productivity and flexibility of production systems. This advanced sequential control (ASC) method is proposed for sequential control systems based on the autonomous decentralized system (ADS) architecture. The ADS defines the system software and message formats and makes it easy to expand the number of devices and software modules. The ASC method increases productivity because it minimizes the processing and adjustment times of production lines by adjusting the starting times of production processes automatically. Experimental evaluation results of the ASC method showed that it increases the productivity of production systems. It is also applied to an actual production system and the results are reported.

High accuracy, high reliability, and high performance have to be simultaneously satisfied to achieve high productivity of the latest processing equipment. High flexibility is also required because many options are available and processing equipment is modified frequently. A high-assurance-system (HAS) model for processing equipment has been developed according to the concept of an Autonomous Decentralized System (ADS). Heterogeneous devices, that have same function and diverse qualities, are utilized to assure the different requirements of high accuracy, high reliability, and high performance simultaneously. The Data Property (DP) and Assurance Manager (AM) are proposed in this model. Different accuracy, reliability, and performance indices characterize each device, and the DP describes the differences of the properties of the data transmitted from these heterogeneous devices. The AM assures not only high reliability but also high performance and high accuracy by utilizing the heterogeneity of data described by the DP. The HAS model was applied to a device-level system used in processing equipment, and its effectiveness was verified by simulating a pressure-control system.