Abstract
Stability is one of the main qualities of control systems, expressing the ability of the system to maintain its current state under the influence of external influences. The study of system stability plays a key role in medicine, psychology, engineering, etc. For example, in psychology, the correct regulation of a person's stress state allows her to withstand life difficulties, adverse pressure of circumstances, maintain health and efficiency. The benefit of analysys the stability of systems is that, having determined the degree of stability of the designed system, it is possible to develop measures and determine means to optimize its structure and parameters, make the system workable and useful. The advantage of using graphoanalytic methods over analytical ones lies in their clarity and simple interpretation. In this paper, models of control objects are considered, and the task of analyzing the stability of the system according to the Nyquist criterion is presented. This criterion allows us to assess the stability of a closed automatic control systems based on the frequency characteristics of an open system. An algorithm for constructing a Nyquist hodograph is also provided, which makes it easy to determine the stability of the system according to the schedule. The paper also provides a comparative analysis of a stable and unstable object, as well as the features of their management. The models presented in this paper can be applied to solving applied management problems in the field of medicine, psychology, technology, economics, etc.