The paper presents some results in CAD of computer based control structures for large scale systems. The hardware configuration has to be designed so that the overall cost of the system is minimized and the performance requirements are met. The CPTCON software system can automatically take over some phases in the design process. This conversationnal package is available on PDP compatible machines including the Romanian minicomputers such as I-100 or CORAL 4011/4030. Some experimental results are presented.

The use of optimization techniques in production control is discussed. Two optimization problems in relation to typical process industry complexes are formulated. A modified version of Tamura's algorithm is reviewed. The promising performance of the computerised algorithms is illustrated by numerical results. DISPATCHER, a practical operative decision support system, is described.

The paper presents some results in CAD of multilevel control laws for large scale interconnected systems by using hierarchical optimization algorithms (MESINT — software package) as well as for optimizing the physical computer — based control structures in order to minimize the "processing costs" (OPTCON — system).

On revoit l'utilisation d'un algorithme d'optimisation hierarchique dans l'ordonnancement de la production de systemes de grande taille dans le domaine des processus industriels

A presentation of the possibility of using hierarchical optimization algorithms within practical systems for computer assisted production control is intended. It is shown how an optimization problem can be formulated in order to cope with the multiple objectives of the system. A practical large example is given. A computer package which uses multilevel algorithms is described.

This paper reviews in an integrative manner some methodological and practical aspects of hierarchical control systems in large-scale chemical production complexes and steelworks made of many strongly or weakly interconnected processes sharing common resources. The paper presents practical problems about the production control within a multilevel “dispatcher” system. The recommended structure represents an attempt to implement multilevel philosophy and computing schemes within the frame of multiloop control systems consisting of a set of units operating in a decentralized but coordinated manner. The basic idea of the structure is that each unit, at any level, operating at different periods of time, “strives” to make local decisions that meet the recommended coupling variables trajectories previously agreed at the next higher level (generally using multilevel techniques). When some coupling outputs are not controlled in a satisfactory way, the higher level unit is activated. The methods are designed to meet the natural needs that occur when the human decision makers and operators are within the control system. An example of applying the proposed structure in industrial environment is presented. Some problems concerning static and dynamic optimization multilevel methods, open loop and closed loop decentralized highly reliable controllers are presented. All the elements may be considered as program modules of a computer package that supports a hierarchical control structure.