Home – Home – Jornals – 2017 number 6

A problem of control of trajectory motion of a quadrotor vehicle is considered. The choice of the form of required differential equations in the previously proposed method of tracking of a moving target is justified. The workability of the control system in the presence of measurement noise and external perturbations is confirmed by results of experiments with the AR.Drone quadrotor.

A structural technology of multicriterial optimization of control of technical objects with distributed parameters is proposed. The technology is based on a single-criterion version in the form of the minmax convolution of normalized performance criteria. The approach under development is based on the transition to an equivalent form of the variational problem with constraints, with the problem solution being a priori Pareto-effective. Further procedures of preliminary parametrization of control actions and subsequent reduction to a special problem of semi-infinite programming make it possible to find the sought extremals with the use of their Chebyshev properties and fundamental laws of the subject domain. An example of multicriterial optimization of operation modes of an engineering thermophysics object is presented, which is of independent interest.

The problem of asymptotic estimation of a linear combination of variables of the state of a bilinear dynamical system using a minimum-order observer is considered. An algorithm for calculating the matrix coefficients of a functional observer using the technology of canonization of matrices is proposed, and conditions for the solvability of the synthesis problem are formulated.

The problem of dynamic decoupling of control channels for multidimensional objects is aimed at autonomization of control of output variables of the object, which is ensured by means of including special correcting links into the control system. A new method of solving this problem is proposed, where decoupling is provided by a block of dynamic correction. The desired result of decoupling is represented by a standard model with separate control channels. The mathematical apparatus applied for calculating the correction block is based on the formalism of linear-quadratic optimization, where the optimized integral quadratic criteria serve as a measure of deviation of the transient characteristics of the corrected object from their desired (standard) values.

A hardware-software platform is presented, which is designed for the development and half-sized simulation of flying vehicle control systems. This platform ensures the construction of the mathematical model of the object, development of algorithms and software for onboard radioelectronic equipment and on-ground control station, and visualization of the three-dimensional model of the vehicle and external environment of the cockpit in the simulator training mode.

The problem of designing a control system for a stand for strength tests of aircraft structures is considered. A method for calculating the parameters of a proportional-integral controller (control algorithm) using the motion separation method for the test stand taking into account the delay effect in the control channel is presented. A structure of the adaptive algorithm is proposed that limits the amplitude of high-frequency oscillations in the control system with a change in the direction of motion of the rod of the hydraulic cylinders and provides the specified accuracy and quality of transients at all stages of the loading cyclogram of structures. The results of tests of the developed control system with the adaptive control algorithm on an experimental strength test stand for aircraft structures are given.

A method of formation of test signals is proposed for studying the aerodynamic characteristics of flying vehicles with the use of the technology of freely flying dynamically similar models. Simultaneous excitation of all input channels in a prescribed frequency band by a set of mutually orthogonal signals is applied to increase the efficiency. A modified method of calculating the set of mutually orthogonal sinusoidal signals with a small normalized peak factor is presented. Results of simulating the motion of a flying vehicle in the MATLAB/Simulink environment with the use of the developed method of test signal formation are reported.

A joint phase-locked loop for tuning the angular shifts (velocity) and Euclidean norm of three-phase voltages of an autonomous inverter to the same network parameters is designed, which can be used, in particular, to equalize the potentials of two parallel-connected power sources at the fundamental harmonic at the moments of switching the stator windings of an asynchronous AC motor from a converter to a centralized power-supply system and back. Technical implementation of the developed synchronization algorithm will significantly reduce the inductance of the equalization reactor and exclude emergency operation modes in power circuits of the electric drive.

A new approach to the synthesis of an automated control system for the process of applying a porous insulation on a conductive cable core is considered, which is based on using structurally and parametrically optimized digital controllers of an arbitrary order instead of calculating typical PID controllers using known methods. The digital controller is clocked by signals of a clock length sensor from a measuring wheel, instead of a timer signal, which provides the robust properties of the system with respect to the changing rate of insulation. Settings of digital controllers according to the criterion based on the need to ensure the achievement of operational characteristics of the manufactured cable are determined on a simulation model of stochastic extrusion and are minimized by moving a regular simplex in the parameter space of the tuned controller.

A method for designing Takagi-Sugeno fuzzy systems is proposed in which the structure of the systems is generated using a piecewise linear initialization algorithm, and parameters are optimized using a meta-heuristic algorithm. The obtained systems are tested against real data sets. The influence of some parameters of this algorithm on the approximation accuracy are analyzed. Estimates of the approximation accuracy and the number of fuzzy rules are compared with four known methods of design

Issues of designing gradiometric transducers with ferroprobe sensors are considered. The regions of application of magnetic flux field gradiometers are determined. The structure and the relative position of a bi-element transducer with ferroprobe sensors are proposed. It is assumed that the ferroprobe sensors are strictly coaxial in the body a gradiometric transducer (GMT). Elements of the classical approach to the mathematical modeling of the spatial position of solids are considered. The bases of the body of the GMT and their transformation during spatial displacement of the gradiometer are given. The problems of mathematical modeling of gradiometric transducres are formulated, basic mathematical models of GMT with a bi-element ferroprobe are developed, and the mathematical models are analyzed. A computer experiment was performed. Difference signals from the ferroprobe sensors of the gradiometer for the vertical and horizontal position of its body are shown graphically as functions of the magnitude and direction of the geomagnetic field strength vector.

This paper describes the study of temperature in the flowing part of a turbine on the informative parameters (equivalent to the inductance of primary coils of matching transformers) of single-coil eddy current sensors with a sensitive element in the form of a conductor section, which are used as part of automation systems for testing gas turbine engines. In this case, the objects of temperature influences are both sensors and controlled turbine blades. The existing model of electromagnetic interaction of a sensitive element with the end part of a controlled blade is used to obtain quantitative estimates of temperature changes of equivalent inductances of sensitive elements and primary coils of matching transformers. This model is also used to determine the corresponding changes of the informative parameter of the sensor in the process of experimental studies of temperature influences on it (in the absence of blades in the sensitive region). This paper also presents transformations in the form of relationships of informative parameters with radial and axial displacements at normal (20 ºC) and nominal (1000 ºC) temperatures, and their difference is used to determine the families of functions of temperature influences, which characterize possible temperature errors for any radial and axial displacements in the ranges of their variation.

In most widely used wavelet filtering algorithms, the decomposition coefficients are processed with the use of threshold functions, which makes it possible to account for the ``energy” feature of each expansion coefficient. To some extent, this disadvantage is removed in a class of multiplicative algorithms, which account for the energy of expansion coefficients located in a given proximity from a processed expansion coefficient. However, the effective error minimization in image wavelet filtering requires that a parameter, the choice of the optimal value of which remains to be an unsolved problem, is introduced into these processing algorithms. Therefore, the problem solved in this paper is the estimation of the optimal value of this parameter, which minimizes the root-mean-square error of the filtering. The performed studies showed the effectiveness of the proposed estimation algorithm and the possibility of its use in practice.

This paper describes a model for detection of images obtained in circular microscanning. To detect objects on a low background with the use of an image detection system based on circular microscanning, an approach to image filtering is proposed. The calculation of the noise covariance matrix with respect to the data obtained by the numerical simulation method is used. The calculated matrix is used in filter construction. It is shown that the applied approach makes it possible to increase the signal/noise ratio in image processing with a low background component.

This paper touches upon the problems of constructing a basis for stochastic functions, which represent samples of random numbers with a given distribution law. The algorithm for constructing an approximation model with the use of this basis is described. The general algorithm for signal recovery using the stochastic basis by the least squares method with a given weight function is given. The approach to solving the problem of recovery of blurred images with a known point scattering function by constructing an inverse filter model is proposed.

The article reports the results obtained in the trial of elements of the monitoring system for potentially hazardous areas at Korobkovo deposit of the Kursk Magnetic Anomaly. The system is based on the seismic and deformation measurements aimed to estimate and control shear stiffness of potentially hazardous faults. The fault shear stiffness is estimated through the analysis of parameters of seismic waves in the vicinity of a fault. The sources of seismic signals in the trial were explosions carried out at the neighbor surface and underground mines.

The authors study the influence of physicochemical parameters on methane adsorption capacity of coal and offer the analytical method for the methane adsorption capacity for three-phased condition of methane. It is found that in the depth interval to 300 m below surface, methane adsorption capacity measured in lab can exceed natural gas content of coal obtained from geological exploration data by 30%, and the change in the thermodynamic condition of coal-methane system brings irreversible physicochemical consequences in terms of the altered ratios of physical states of the main components. There is no linear connection between natural gas content of a coal bed and its methane adsorption capacity with respect to occurrence depth. The application of Big Data in treatment and interpretation of large data flows is described. The theoretical data predicted using the proposed method and the experimental data on methane content of Kuzbass coal agree.

In focus of the article is minimization of aftereffects of the large-scale accident connected with the flooding of Berezniki Potash Mine in the Perm Krai. The authors construct a synthesized geomechanical model of the flooded mine to show the mining conditions, the process of salt rock dissolution and the elastoplastic behavior of deformation and failure of undermined rock mass in time. Approaches to analyzing intensity of degeneration of load-bearing elements of the open stoping system as a consequence of salt rock dissolving are proposed. The obtained estimates are the parametric framework for prediction of the ground surface deformation using 3D mathematical modeling. The geomechanical calculation results are used in the managerial decision-making on safety of the industrial and civil infrastructure within the hazardous territory.

Gas-water relative permeability (GWP) is measured in the tests of full-diameter cores. Based on the obtained GWP curves, the standard normalized curves are plotted for three types of carbonate reservoirs: matrix pore, fracture and solution pore. The corresponding gas and water two-phase flow model was deduced by considering stress sensitivity and non-Darcy effect, and the IPR curve calculation and analysis of gas wells of the three types were carried out. Based on huge gap between the matrix and fracture permeability, the phenomenon of gas drive water mainly exists in the cracks. So the conventional gas-water relative permeability of fractured gas reservoirs was modified. The research will lay the foundation for the application of gas reservoir engineering calculation with the production and application of numerical simulation technology to make dynamic forecast.

The integrated study of coal is performed using methods of optical and electron paramagnetic resonances, infrared spectroscopy and Raman spectroscopy. It is found that gas content of coal is governed by the rank of coal and its material constitution as well as by the coal bed structure at the macro-, micro- and nano-levels which interwork. It is discovered that the size and amount of bubbles, of paleo-origin presumably, and the content of coalbed methane are related. The influence of each scale level of the coal bed structure on the gas content is revealed. The authors illustrate benefits of the integrated study of gas-bearing coal with the physical methods that complement one the other at different levels of coal structure.

The authors solve the problem on forces required to change drilling path of air hammers in soil. Soil mass is assumed a rigid-plastic medium with the Mohr-Coulomb yield, and the air hammer deviator is considered as a nondeformable body. The problem is solved in two stages: introduction of the deviator in soil and travel of the air hammer in soil with the rear deviated at a certain angle. The loads applied to the rear, the forces and the moment required to changing the path of an air hammer in soil are calculated.

The substantiated dimensionless criterion of jamming characterizes relationship between the temperature of the contact links of spiroid gearing and the load-bearing capacity of an oil film. Based on the review of the existing tribotechnical systems used in scoring resistance testing, a physical model of spiroid gearing is selected. The test data obtained on a rolling-and-disc scheme of a friction assembly are presented. The relations between the friction coefficient in the spiroid gearing and the unit load are determined for the steel-steel material couples in a range of slip velocities and temperatures. A design procedure for spiroid gearing with respect to jamming is proposed.

Under study is a production system composed of a power motor, compressor, pneumatic percussive machine and a treated medium. Based on the generalized theoretical and experimental data, the author relates productiveness of pneumatic percussive machines, energy intake of rock breakage in the uplands with the rare atmosphere and elevation of the machine work site above sea level. The obtained results offer a reason-why approach to selection of the pneumatic percussive machine parameters for operation in the uplands.

The authors describe a technical approach to validating efficient regimes and process flow charts for draglines in open pit mining in permafrost zone; the approach integrates modeling data on temperature conditions of permafrost treated by blasting, geometrical parameters of a dragline face and interaction of work cycle time and face rock temperature in different seasons. It is shown that a dragline has the appreciably reduced productivity in slice-by-slice handling of broken-rock disintegration having negative temperature.

The article presents a procedure to select loading and transportation machines for an open pit complex ore mine. The choice of a shovel-dump truck production system is validated using a statistical testing method (Monte Carlo technique). Stop-watch readings allowed relating the productivity of the production system, degree of ore fragmentation and content of oversizes; the soundness of the choice of the production system based on the revealed criterion was proved. Using the law of the Palm flows, the authors determine the number and sequence of dump trucks for loading in a one-server system.

The authors have studied the mechanism of the controlled modification of composition, structure, chemistry, physicochemical and process properties of columbite, tantalite, zircon and feldspar at the meso-, micro- and nanoscales after nonthermal treatment by high-voltage nanosecond electromagnetic pulses. The studies used the methods of X-ray photoelectron spectroscopy, scanning electron and atomic force microscopy, potentiometric titration, electromigration chromatography, Kelvin probe force microscopy, microhardness metering and assessment of hydrophobic behavior and flotation activity of the minerals. It is found that the change in the chemical state of atoms on the surface of the minerals is mainly connected with the sequential transformation of stages in the process of formation and modification of the functional cover of a mineral surface, with the variation in the ratio of different type hydroxyl groups on the surface of columbite, zircon and feldspar, which conditions contrast physicochemical properties of rare metal minerals and improves selectivity of their separation by flotation.

The authors analyze collecting capacity of desorbable species of xanthates. Desorbable species of a reagent are understood as the species capable to transfer from mineral particle to air bubble, i.e. to gas-liquid interface, at the moment of rupture of an interlayer between these interacting objects. Flotation process performance is evaluated at the presence of a mixed coating resulting from physical and chemical adsorption and in the presence of a chemosorption coating only. The rates of spreading products of interaction between butyl ethyl xanthates and lead nitrate over water surface are found. The spreading rates and collecting capacities of the mentioned reagents are correlated. It is found that an increase in the length of the hydrocarbon fragment increases collecting capacity of a reagent and the rate of spreading of its products over water surface.

In terms of sulfide copper-molybdenum ore of Sorsk stockwork deposit (Republic of Khakasia), the authors discuss the option of selective dissociation of minerals. The scope of the discussion embraces effect of pulsed-discharge treatment on particle-size indexes, structural and chemical properties and floatability of objects of the study. It is shown that the pulse-discharge treatment in a greater degree influences copper sulfides and levels their floatability while surface of molybdenite undergoes minor alteration. The pulse-discharge treatment allows enhancing flotation selectivity efficiency in separation of copper sulfides and molybdenite, and promotes removal of hydrophobic molybdenite film from quartz surface, which results in production of high-quality molybdenite concentrates.

Under analysis is on-site extractability of nonferrous and noble metals from tailings by leaching using natural reagents (humus acids, water, lignin). Redistribution of nonferrous and noble metals in percolation bed made of old tailings in the Norilsk copper-nickel ore field is studied. Kinetics of dissolving of nonferrous and noble metals under capillary ascensional percolation is investigated. It is shown that directional capillary percolation of solutions is applicable to extraction of nonferrous and noble metals from long-term storage mining waste.

When gold occurs in mining waste for a long time, it becomes coated with dense films of hydroxide of iron, manganese, copper and silver sulfides, hydromica powder and clayey particles, which greatly complicates concentration of such gold by gravity. An efficient method to remove such coatings from gold is treatment of waste using chemical reagents based on halogen-containing compounds. The article presents experimental results on extraction of fine gold from tailings of sluice boxes and dredging classifiers using such chemical reagents.

The undertaken research is aimed to reveal optimal physicochemical conditions for deep conversion of calcium-bearing alumosilicate raw material. An innovative technology of integrated extraction of nano-dispersion amorphous silica, alumina, calcium fluoride and other useful elements has been developed.

Under consideration is the influence of various crushing techniques on the particle-size distribution and selectivity of dissociation of basic mineral components in the composition of Dalnegorsk complex ore under pretreatment. Distribution of basic elements per size grades is determined in crushing feed and in products of magnetic separation and flotation. Conditions of preparation and separation of disintegration products are described. The authors illustrate the change in the dissociation selectivity criterion in jaw crushing and in disintegration in press to prepare different size ore for processing by magnetic separation and flotation.

In terms of Tashtagol Mine, the authors address the issues connected with the determination of surface shape in cavities formed by blasts of explosive charges in high-stress rock mass structured as a hierarchy of blocks. Laser scanning of a cavity offers the data on linear and angular characteristics of the cavity surface. The analysis of the surface structure provides details of the rock mass block hierarchy, which essentially influences formation of the roof and sidewalls of the cavity. Individual areas of the cavity surface are described with the help of approximation of measured coordinates of the cavity boundary in the cross sections using the second order curves, including circumferences and ellipses the radius of which are canonically connected with the phenomenon of zonal disintegration of rock mass.

A method for the selective removal of indium from solutions (sol.) of acid leaching of Waelz zinc oxide (0.02–0.1 g/dm³ In) was proposed. It is an alternative technique for extraction. Adsorption over modified montmorillonite that is the Меtоsol reagent (reag.) in dynamic mode allows maximally implementing the reagent exchange capacity with the optimum cycle of sorption/desorption operations. Adsorption of iron (II) and zinc ions in static mode was detected. It is driven by the formation of intermolecular bonds with the developed surface of modified aluminosilicate. The formation of a stationary front of indium ion sorption from a polycomponent solution over the Меtоsol mineral sorbent due to predominant adsorption of In³⁺ compared to Fe²⁺ and Zn²⁺ was found in dynamic mode. The latter cations are replaced by In³⁺ ions that form chelates with ionogenic groups of di(2-ethylhexyl)phosphoric acid. Output curves of sorption of In ions at unit load V_sol/V_reag = 1–2.7 h^–1 and temperatures of 298–328 K are mainly S-shaped. The inflection point is shifted to the low-value range of the specific volume of the past solution (V_sol/V_reag), which indicates slowing down the ion diffusion rate in sorbent. Indium ions passing into the filtrate comes much earlier (V_sol(1)/V_sol = 3.33–0.66), the width of the chromatographic front (ΔV_sol /V_reag = 12.1–12.35) increases, the full dynamic exchange capacity (FDEC = 0.572–0.237 µmol-eq/g) and the utilization rate of the resin bed are decreased with increasing the linear rate (ω_0.5) of the transmission of the eluent through a column in the range 4.78 to 12.74 cm/h. The width of the chromatographic front (ΔV_sol /V_reag = 12.1–10.24) decreases; the full dynamic exchange capacity (FDEC = 0.572–1.293 mol-eq/g) and the utilization rate of the resin bed (η = 0.226–0.256) are increased, which testifies monitoring the process of sorption of indium by mixed diffusion. The Меtоsol reagent allows selectively extracting indium from production solutions in dynamic mode.

Mechanochemical synthesis of sodium thiosulphate pentahydrate (Na₂S₂O₃•5H₂O) was carried out for the first time in a planetary ball mill by mechanical activation of a suspension of sodium sulphate (Na₂SO₃) and sulphur (S). The degree of Na₂SO₃ + S = Na₂S₂O₃ reaction in suspension solution at soft and short mechanical activation conditions is almost 95 %, as established by methods of iodometric titration, X-ray phase and thermal analysis.

An increase in the octane number of straight-run fractions of normal hydrocarbons С₅–С₆ up to 92 points by research octane number (RON) through their catalytic isomerisation appears to be an effective solution of the critical applied task of changing the structure of the domestic gasoline pool. Isomerisates have a high octane number and do not contain hazardous sulphur compounds, aromatic hydrocarbons and particularly, benzene. Herewith, selection of the optimum technology for isomerisation of light gasoline fractions considering a peculiarity of a specific refinery is an important scientific and technical issue. Additionally, a number of complex multiple-factor tasks, such as ensuring of a specified quality and quantity of raw materials, maintaining the optimum activity of the used catalysts, and also providing the optimum operation modes for each complex block considering energy and resource efficiency in manufacturing might arise. To describe nonstationary catalytic processes of catalytic processing of light alkanes the mathematical modelling method is used. This paper assesses the operating efficiency of catalysts for isomerisation of light gasoline fractions based on Pt/SO₄^2–/ZrO₂ and Pt/Cl^–/Al₂O₃ using the mathematical modelling method for nonstationary catalytic processing of hydrocarbon raw materials. Catalysts based on sulphated zirconium oxide retain high activities and stabilities during the entire operating cycle, while catalytic systems based on chlorinated alumina are deactivated faster. Isomerisation process scheme with the recycle of unreacted C₅ and C₆ hydrocarbons involves significant capital and operating costs, however, its use will allow increasing the RON of isomerisates in 10–12 points.

The paper justifies factors and causes of hard washability of finely disseminated copper-nickel ore, the main of which are incomplete and insufficiently selective expansion of sulphide and rock-forming mineral aggregates due to low mechanical interactions in ball mills, with the result that a large number of non-ferrous and precious metals pass to concentration production wastes adding to technogenic accumulations. Technological possibilities of high-energy and high-velocity impact grinding in a disintegrator, wherein increased destructive effects lead to an increase in expansion of aggregates, were explored. The opportunity to control energy and free kick speed allows carrying out the destruction mainly along the boundaries of mineral intergrowths and reducing the amount of the fine fraction slurry in grinding products. However, an increase in the disintegration rate to 7200 rpm did not result in obtaining flotation size products –0.071+0.02 mm, and a substantial part of ore remains in the larger, difficult-to-float condition. With a view to optimising opening of mineral associations by granulometric composition, the principle of stage grinding that allows consistently in the regimes of increasing energy effects regrinding larger ore fractions and liberating minerals from genetic associations with increased strength was proposed. This methodological approach allowed in the optimum rate mode destructing sulphide minerals and obtaining during flotation separation concentrates with increased content of non-ferrous metals, which offers opportunities for improvement of metallurgical methods for processing concentrates. More high-energy destruction allows liberating residual amounts of sulphides in rock associations and transferring into reject materials to 50 % of ore rocks. It is noteworthy that herewith, a large number of nickel compounds found in aggregates with rock formations are released, which is of great importance for increasing nickel extraction into concentrates. The carried-out research demonstrates that high-energy grinding is an advanced method for selective destruction of aggregates and mineral liberation in finely impregnated ores prior to concentration processes.

The paper demonstrates an opportunity to determine the elemental composition of the combustible mass of plant biomass, peat, and fossil coal based on technical analysis findings followed by the assessment of the low heat value of solid fuel. This approach may be useful with the absence of elemental analysis findings and the lower heat of combustion of solid fuel. The content of carbon as the main element that forms the structure of solid fuel may be assessed via the yield of volatile matter, as demonstrated in the first case. Empirical dependencies of H_at/C_at and O_at/C_at ratios on carbon content in solid fuel, against which the low heat value of solid fuel with a sulphur content of no more than 2 % is calculated, are defined. Herewith, the deviation from the literature data did not exceed 10 %. The second option examines an opportunity to determine H_at/C_at and O_at/C_at ratios via the yield of volatile matter. The low heat values of solid fuels with sulphur contents of no more than 2 % were calculated on the basis of the resulting empirical dependencies; herewith, the deviation from the known values does not exceed 6 %. The use of the resulting empirical dependencies to define the low heat values of solid fuels with a sulphur content of 2.1–8.4 % in some cases, gives an increase in deviations from the literature data within 12–14 %.

The electronic structure of three aza-boron-dipyridomethene derivatives containing different hydrocarbon groups at the boron atom is studied by ultraviolet photoelectron spectroscopy and calculations at the density functional theory level. According to the experimental and theoretical data, the higher occupied molecular orbitals of anthracene, acridine, and the studied complexes are of the same character. For the three studied compounds, the effect of alkyl and phenyl substituents on the electronic structure is determined. The parameters of the electronic structure of aza-boron-dipyridomethene (phenyl groups at the boron atom) and its b-diketonate analogue are compared. It is shown that in an energy range up to 11 eV the calculated results correlate with the ultraviolet photoelectron spectra.