Set-theory model of the aircraft hydraulic system working fluid state

The article is devoted to the development of a set-theory model of the aircraft hydraulic system working fluid state using the mathematical apparatus of the set theory. The relevance of the work is connected with the necessity of developing a universal mathematical model of the hydraulic fluid state. The model is to form the basis of an intelligent system to control the working fluid state on board the aircraft. As a result, a general expression is obtained that allows describing the working fluid state at an arbitrary moment of time using its basic parameters, namely contamination, viscosity, density, chemical and temperature properties. A hierarchy of parameters of the working fluid state taking into account the diagnostic value of the information obtained during their measurement is constructed. The main classes of states are distinguished among all possible states of the working fluid. These are the ideal state, the normal state, pre-failure and failure. Each of them is described by a set of configurations of all possible values of the main parameters. А technique for optimizing the time of the inspection of technical condition based on the calculation of the change in the entropy of the working fluid is proposed.