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The paper considers the issue of approbation of adaptive predictive control for heating, ventilation and air conditioning systems, shows the possibility of improving the regulation processes by its application on example of ventilation system. The idea of control using predictive model is presented, the principles of control using MPC controller are noted, the controller structure and the criterion for choosing the optimal values of control signal are considered. The feature of adaptive predictive control is the presence of the mathematical model for control object, which accurately describes its behavior. The MPC controller determines the sequence of control signal values that provides the best predicted trajectory for controlled variable. The implementation of the MPC approach is shown on the example of supply VAV ventilation system of the classroom. In the considered ventilation system, the change of heat load for the room is compensated by the change of amount of supply air coming from the central supply ventilation unit at its constant temperature. To simulate ventilation system in the Simulink environment of the MATLAB application package, the block diagram was developed, and the Model Predictive Control Toolbox was used to synthesize the MPC controller. The study of transient processes in VAV ventilation system was carried out, transient process in the system without controller, with PID controller and MPC controller were compared. Comparison of the results showed that the use of the MPC controller makes it possible to improve the regulation process of thermal regime in the room by increasing the regulation quality.

This paper is devoted to obtaining a solution to the problem of parametric vibrations and dynamic stability of thin-walled underground oil pipelines, taking into account the effect of a damper. An equation has been obtained that allows estimating the dynamic stability of underground oil pipelines, which consists in constructing regions on the plane of the parameters ωmn, ω0 and the longitudinal force parameter P, as well as the internal pressure p0, where ωmn is the frequency of free vibrations, ω0 is the excitation frequency. The assessment of the dynamic stability of the oil pipeline section is made for the known values of ωmn, ω0, p0, P, k by finding a point. If the point does not fall into the outlined area, it means that dynamic stability is ensured, otherwise there is a danger of parametric resonance.

This paper is based on the equation obtained earlier by V.G. Sokolov to find the frequencies of natural vibrations of straight sections of large-diameter pipelines. In this work, to take into account the effect of hydrostatic pressure on the pipeline wall from oil flowing at different speeds, the solution obtained by M.A. Ilgamov and A.S. Volmyr is used. At the same time, the effect of a stationary fluid flow on the pipeline wall is taken into account in the equation written in forces for the last term of the normal component of inertia forces. The resulting modified equation allows determining the frequency characteristics of the pipeline both according to the rod theory (without taking into account the deformation of the cross section) and according to the theory of shells (taking into account the deformation of the cross section).

The article is about the study of the frequencies of free oscillations of a large-diameter polyethylene gas pipeline with a semi-underground installation, which carried out on the basis of the solution for a semi-underground thin-walled steel pipeline of large diameter. As a result of oscillations, the cross section of the pipeline is deformed, but it strongly depends on the geometrical and mechanical parameters set, for example, on the stiffness coefficient of the elastic medium