Vol 30, No 3 (2022)

A mathematical model and a block diagram of an information-measuring system based on the effect of interruption by micrometeoroids of a light curtain of multiple re-reflected optical rays formed by a line of LEDs are presented. The description of options for the formation of a light curtain at different angles of the optical beam is given. The maximum allowable distance between the source and receiver of optical radiation is determined, taking into account the distance between the planes, the reflection coefficient of mirror surfaces, the parameters of the recorded micrometeoroids and external destabilizing factors.

It is proposed to take into account the influence of uncontrolled disturbances on the regulation of pressure in the stabilization column of a catalytic reforming unit by changing the coefficients of the denominator polynomial of the transfer function of the automatic pressure control system based on robust stability methods. To describe the problem in a general form, a general view of the polynomial of the denominator of the transfer function of the automatic pressure control system in the stabilization column of the catalytic reformer is obtained. The purpose of the study is to determine the maximum range of change in the coefficients of the polynomial of the denominator of the transfer function of an automatic pressure control system in the stabilization column of a catalytic reformer, at which robust stability is maintained. Methods - methods of robust stability, automatic control theory. A family of polynomials of the denominator of the transfer function of the automatic pressure control system in the stabilization column of a catalytic reformer with squared uncertainty parameters is considered.The problem of determining the area of robust stability of a family of polynomials is reduced to determining the areas of stability of four edge polynomials and the intersection of all areas to determine the area of robust stability of the family. In general, the problem of determining the robust stability of each edge polynomial is described. To determine the area of robust stability of the family of polynomials of the denominator of the transfer function of the automatic pressure control system in the stabilization column of the catalytic reformer, three polynomials, including the nominal one, are specified. Based on the general description of the problem, the radius of stability of each edge polynomial is determined using a graphical criterion and the construction of a Tsypkin-Polyak hodograph. Results - based on the intersection of the stability regions of four rib polynomials, the robust stability region of the family of polynomials of the denominator of the transfer function of the automatic pressure control system in the stabilization column of the catalytic reformer with a stability radius of 1.5 was determined. Conclusion - this result can be used in the development of an automatic pressure control system in the stabilization column of the catalytic reformer and the choice of regulator settings.

It is proposed, based on the spectral representation of the system, to solve the problem of synthesis of a distributed control plant described by PDE, using LMI technique. The system is described by a spectral characteristic vector with the amplitudes of the space-time modes of the Fourier series as components. The spectral characteristic vector is satisfied to an infinite SLAE composed for an initial PDE using the spectral method. For the spectral plant representation in space-time domain the stability, controllability, and observability criterions are formulated. The procedure of control synthesis on the basis of solving of stabilization problem with full information and observation problem is proposed. The expression for time-dependent matrix regulator gain is received.

The problem of early wear diagnostics of the combined journal-and-thrust bearing of the turbo-pump unit of the liquid-propellant rocket engine NK-33 is considered. The main purpose of the diagnostics is to identify the initial stage of the bearing’s intensive wear. This allows to detect timely the catastrophic destruction of the unit and to prevent the development of emergency destruction of the power plant in general. The significant limitation of the appropriate diagnostic methods was the strict requirements of the inadmissibility of any changes on the number and dimensions of the sensors used in the product body while the existing functions of the turbopump rotor rotation speed monitoring should remain unchanged. The authors proposed a solution based on the replacement of the inductive RPM sensors that are currently used in the turbopump unit parameter monitoring systems with single-coil eddy current sensors with sensitive elements in the form of a conductor segment. This approach made it possible to monitor the axial displacement of the shaft in the combined journal-and-thrust bearing associated with the wear of the assembly and to keep the function of the measuring of the turbopump shaft rotational speed unchanged. The article provides a brief description of the implemented approach to early diagnosis of the condition of the bearing assembly of the NK-33 turbopump unit based on the measurement of the axial displacement of the shaft in the bearing. The technical solutions that implement the approach are based on the use of original single-coil eddy current sensors of a special design with shifted sensing elements, the non-standard converters of their output signals in combination with standard analog-to-digital converters (external modules of the Russian-made L-Card E14-440 ADC) and a PC that provides the control of the data aquisition, processing and visualization. A structural and functional scheme of the control system and its generalized operation algorithm are proposed.

The paper proposes the problem solution of optimal location determining of several power stations in some region. These stations receive primary energy from renewable sources, such as solar panels and wind turbines. At the same time, the condition of the problem includes the availability of information on several perspective areas in this region for the placement of such power stations, as well as information of values and distribution of loads. The developed algorithm for solving of the optimal location selection problem of power stations consists of several stages. The content of the first stage of the algorithm is ranking of possible areas for the location of power stations using local criteria, which are proposed as the specific estimated cost of station arrangement, the remoteness of the proposed location of the power station from loads and settlements. The second stage of the algorithm consists in a set formation of possible areas for the location of stations. And at the final stage of the algorithm, they are ranked using system criteria that evaluate these sets of areas for the location of power stations as a power supply system. The estimated cost of a power supply system arrangement based on power stations, located on areas of the rated set, the specific estimated cost of power stations arrangement, applied to the set of power stations with power lines as an autonomous power supply system, as well as the average rating of areas are proposed as system criteria. In this case, the decision maker, after familiarizing with values of system criteria, sets critical boundaries for each of them. The result of the algorithm is a certain totality of prospective sets for the location of several power stations in a given region, estimates of which according to system criteria are the best correspond to preferences of the decision maker. A feature of the proposed approach is the participation of the decision maker at all stages of design.