The article is an introduction to the special number for "Advanced control and simulation."
It describes the trend of advanced control application and explains clearly what are practically acceptable as industrial products giving well-arranged examples of Fuji Electric's actual applications and their features.
It points out engineering works necessary for the application of new control methods; especially, it emphasizes the importance of computer simulation. As these works needs very high techniques, it suggests the effective use of recent AI technology.

Advanced control is now introduced and put to practical use in measurement and process control systems to realize improved controllability, improved reliability in operation, automation and unmanned operation. The interactive Software SAPL is a design tool for quick and efficient application of advanced control. Utilizing process data bases, it is capable of designing various control parameters for classic or modern control theory-based PID control, dead-time control and optimal control. The paper also introduces an example of actual advanced control systems produced with the SAPL.

In general processes with nonlinear characteristics, the characteristics vary according to the change of operating condition, and the optimal values of control parameters vary according to the nonlinear characteristics of processes and also the secular change of plants.
Two-direction adaptive control is effective to solve these problems; it classifies the variations of process characteristics into very fast variation due to nonlinear process characteristics and slow variation due to secular plant change and adapts control parameters to two directions. This paper introduces a design tool GISTLAX for two-direction adaptive control.

In the case of positioning control in industrial plants such as steel process lines and paper making machines, it was difficult to satisfy both high-accuracy positioning and reducing time required for deceleration because the equipment is large in size and load change is heavy.
This paper describes the positioning control system that has solved these problems by introducing a performance function in conventional control systems.

Fuzzy control is a control method which realizes the same level control as skilled operator's by means of computers Fuji Electric has developed a tool FRUITAX for easily structuring fuzzy control systems and has applied it to actual plants. The FRUITAX operates on microcomputers and process computers, provided with an interactive function, simulation function and support system for designing control rules from operation data.
The paper introduces the configuration, feature and application method of FRUITAX citing chlorine pre-feed control in a water purification plant as an example, and the effect of its application as well.

The expert system incorporating an expert's knowledge to give the same level answers as an expert is useful for readjusting knowledge and easy to be maintained; it is the only example of practical use in knowledge engineering at present. EIXAX, an expert system structuring tool suitable for process control, can structure a knowledge base with Japanese language and formulas and can make inferences in real time. This article describes the configuration, features and support functions of EIXAX, and knowledge representations and inference methods as well.

As FA technology developed from local FMS into CIM aiming at total automation, material flow control which integrates production management systems and shop control systems has been important. The material control system requires flexibility and expandability to cope with frequent specification changes. ΦNET is a material flow control system structuring tool that combines network technology and AI technology for such purpose. This paper describes the concept, system configuration and system structuring procedure of ΦNET and its effectiveness.

Process control requires higher productivity, improved quality, and higher-rate automation, which urges the application of advanced control and AI. AWS is the workstation that performs engineering work for these applications Holding process characteristics out of process data, it executes setting of parameters for advanced control, such as optimal control and adaptive control. Further, it can structure knowledge bases for expert control and perform verification with simulation.

Fuji Electric has developed a practical digital control system for the adaptive control of synchronous generators. The system performs integrated control of excitation and governor systems of a generator, adapting itself to the characteristic change of the power system and the generator. Thus, it suppresses long-period power swing that was difficult to be stabilized by conventional controllers. The improved stability of the power system will bring forth economical effect due to the efficient use of existing equipment.

Main subjects in waterworks are to secure necessary water supply and to complete maintenance-management systems. For this purpose, in addition to raising the level of conventional process supervisory control system, it is necessary to structure an integrated management system that operates and controls subsystems organically and efficiently, regarding the whole facilities of waterworks as a production/conveyance system of water.
Fuji Electric has integrated the waterworks operation and water distribution system, that is the nucleus of waterworks operation and control, and the facilities information management system into an advanced computer system incorporating up-to-date technology.

Recent automation control for sewerage requires the integrated water quantity control of the whole sewerage facilities including sewers distributed over a wide area because of rapid urbanization. For the rain water inflow process, Fuji Electric has established control technology enabling efficient pump operation against flooding by combining a rain water inflow forecast using the AR model and rain water pump operation applying fussy control. For the sewage inflow process, it has developed a smoothing method for sewage inflow quantity by combining a sewage inflow forecast using a statistical technique and Karman's filter method and sewage pump control applying DP method.

Industries require higher quality, higher reliability and increase in labor saving year by year. Since the development of microcomputers has promoted digital control, it is of urgent necessity to establish a new control system based on digital control theory.
This article gives an outline of the minimal order digital observers for motor load toruqe estimation when they are applied to impact drop control and control of an oscillating multi-mass system or to tension estimation and control of an oscillating tension system.

Process control systems now require labor saving, software development and decrease in maintenance cost. Fuji Electric has developed an expert system for energy control on the basis of EIXAX, an AI tool for automatic control, aiming at thorough programless one. The features of the system are firstly that EIXAX, mathematical programming and statistical analysis are packaged, being organically united, on a 32-bit microcomputer and secondly it is configured into an on-demand system incorporating basic application programs and rules beforehand.

For OG systems that perform cooling, dust collecting and recovery of unburnt waste gas of LD converter, increase in waste gas recovery is very important for energy saving. Introducing advanced control utilizing optimal control and adaptive control, Fuji Electric has completed a closed-type OG pressure control system, leading to improvement of waste gas recovery and to an increase in the yield rate of steel production and higher automation as well. The paper describes an outline of the advanced control system applied and the result of actual operation.

Continuous annealing systems have a tendency to combinations of various equipment, high-speed operation and multiproduct multiprocessing, which require high-grade instrumentation techniques. This paper describes the process model, control function and simulation of the strip-temperature control playing an important role in product quality control. Also, it introduces an configuration example of a continuous annealing system using a distributed control system (MICREX).

The cement kiln process has been slow in applying automation because it depends on the ability to experts called burner masters. When the process is expressed in an autoregressive model, the kiln control model is composed of three models, that is stable optimal control, logical-type recovery control and operator-guided corrected control. The paper describes the application method of the model and the result of its application to actual operation, which showed remarkable effects in fuel cost per unit product and stable operation. It suggests that fuzzy control and AI should be applied for further improvement.

Performance improvement of robot manipulators requires high-accuracy positioning and high-speed operation, and application of new control systems has been brought up for discussion.
It was confirmed by simulation that adaptive control was effective against inertia variation in two-degree of freedom manipulators with DD mothers. The troublesome vibration caused by unstable construction at the end of manipulator positioning was analyzed by simulation. The paper describes these results of studies with simulation.