ABSTRACT
The notion of control always implies a plant to which the control is applied, and a target that is to be attained using this control. In practice, control process is realized by means of specially formed exogenous actions applied to the plant. These actions are intended to change some properties of the latter. The block-diagrams illustrate general principles of control and bear generalized character. In practice, any control system can be represented in the form of a detailed block-diagram, which is determined by system elements and their physical nature, as well as by their interaction. A widely used method of structural representation of control systems consists m splitting the system onto directed action elements that interact on the basis of three basic kinds of connections: series, parallel, and feedback. A relatively small number of controllable and measurable values which gives basic information on system performance are chosen as state variables.
