the branch of automation that deals with the methods used in the automated designing of control systems with specified properties on the basis of limited underlying data. It differs from conventional design in that the most laborious design stages, such as the calculation of alternatives, are done by electronic computers. Automated control design is based on the theory of optimal control systems.

Automated control design has three basic stages. In the first stage, a mathematical model is developed of the system being designed. Such a model may be represented by a system of differential equations. The mathematical model reflects the relations between the state variables and the control variables. Examples of state variables are the speed of the system, the system’s reliability, the system’s accuracy, and the quality of the manufactured product. The control variables act on the system being designed and thus effect changes in the state variables. The mathemtical model, together with the specified limits for the state variables and the control variables, defines the region of permissible alternatives for the design of the system.

In the second stage, a target function, or optimization criterion, is obtained on the basis of the mathematical model. This function represents the mathematically formulated objective of the design process. The target function may simultaneously reflect several state variables and some additional economic indexes, such as profit and costs. The control variables are also reflected in the target function. The set of control variables determines the various alternatives for the system being designed. In some of the alternatives the target function attains an extremum. This extremum determines the optimal region, from which one of the alternatives is selected for realization. The second stage is often combined with the first stage.

In the third stage means are developed for the realization of the chosen system alternative, which has been obtained in the form of general mathematical relations (recommendations). Thus the third stage involves the preparation of, for example, functional, structural, dynamic, electric-circuit, and assembly diagrams.