This article proposes a method for correcting the intermediate trajectory obtained by one of the planning methods, taking into account the limitations on the linear velocity and acceleration of the apparatus, as well as on the angle of its pitch. This technique is combined with the smoothing procedure, which includes the stage of minimizing the length of a piecewise polyline trajectory and rounding the corners at the vertices with the construction of a smooth time parametric representation of it using the modified Dubins method.

Keywords: robotics complex, unmanned aerial vehicle, stability and controllability of the vehicle, motion planning, local adjustment of the planned trajectory, reduction of energy costs

When choosing an intensification method, the assessment of thermal-hydraulic efficiency is an important criterion. In this paper, the thermal-hydraulic efficiency of the pulsating method of heat transfer intensification was assessed as applied to an in-line tube bundle. The thermohydraulic efficiency was estimated by comparing the ratio of the increase in the Nusselt number to the increase in the coefficient of friction factor in a pulsating flow compared to a stationary flow. The coefficient of friction factor was determined by numerical simulation in AnsysFluent. The results of a numerical study showed that an increase in the product of the pulsation amplitude and the Strouhal number leads to a decrease in the thermal-hydraulic efficiency at all values of the Reynolds number, while the thermal-hydraulic efficiency is higher at the minimum values of the Reynolds number.

Keywords: Reynolds analogy factor, flow pulsation, heat transfer enhancement, thermal hydraulic efficiency.

In the work, a method was implemented that allowed estimating the parameters of a control object based on the objective function, the least squares method, and the solution to the system of nonlinear equations was the Levenberg-Marquardt method. The numerical and laboratory experiments carried out allow us to speak about the effectiveness of the proposed method.

Keywords: identification, optimization, least squares method, Levenberg-Marquardt method, differential equation

Construction control at the stage of preparation for the commissioning of the object requires checking the quality of external enclosing structures according to the air permeability parameter. The GOST 31167 methodology available to specialists, as well as other similar methods, is based on the principle of creating and maintaining the required pressure drop in the room and beyond its boundary for a long time while simultaneously determining the flow rate of the air supplied for testing. The essence of this method is that it limits the possibility of quantifying the values of air permeability through specific sections of external enclosing structures and allows you to determine only complex indicators for one room or a group of rooms without specifying specific values of defects in various types of exterior walls, window fillings, door openings, and abutments. The proposed method of qualitative and quantitative assessment of air permeability is based on an additional analysis of the temperature fields of the internal surfaces of external enclosing structures while ensuring a given difference in pressure and temperature of the indoor and outdoor air entering the room by creating a vacuum. Conducting field studies is necessarily complemented by the results of numerical modeling of structures in undisturbed and defective states.

Keywords: non-stationary heat transfer, numerical modeling, calculation of temperatures in the defect region, analysis of temperature fields, air permeability resistance, experimental evaluation of air permeability

In this paper, we review a number of algorithms for solving the problem of building a map and the problem of SLAM - Simultaneous localization and mapping - in various formulations. These tasks are solved on a graph structure that describes a mine working, in which a localization system from stationary access points is installed. To solve the SLAM problem, the FastSLAM algorithm is used in various modifications, depending on the method for estimating the positions of access points. In all the proposed solutions, it was possible to achieve an error in estimating the positions of access points of no more than 2 meters. The problem of building a map is solved as a combinatorial problem of searching for a permutation of access points by known positions. The proposed permutation search algorithm showed tangible advantages in terms of execution time over the exhaustive search method on systems with 5 or more access points.

Keywords: graph, mining, localization, map construction, SLAM, MCMC, particle filter, Kalman filter, Bayes method

The comparison of technological settlement values during the construction of various variants of diaphragm wall is presented. Numerical modeling of the construction of a diaphragm wall enclosure was performed in weak water-saturated clayey soils using the Plaxis 3D software package. The investigation results revealed that the technological settlement of the building foundation caused by constructing a trench-type diaphragm wall significantly exceeds the values observed in the construction of a diaphragm wall with augered piles.

Keywords: technological settlement, excavation enclosure, diaphragm wall, numerical modeling, Plaxis

The article discusses a mathematical model of an excavator's hydraulic shears, which describes the functional dependencies of their main parameters based on regression statistics. An algorithm for the process of selecting optimal parameters for hydraulic shears used to destroy metal structures during the dismantling process is presented, and a description of the developed software application that automates the process of selecting these parameters is given. The application described in the article will reduce the time required for the design stage of excavator attachments.

Keywords: attachments, hydraulic shears, dismantling, metal cutting, design, mathematical model, automation, selection of parameters, algorithm, program

The article discusses automatic selection of coefficients for PID controllers of quadcopter motors based on a 3D model. This selection became possible thanks to the method discussed in the article for exporting a 3D model of a quadcopter, created in the Solidworks CAD system, into the Matlab/Simulink environment, as well as with the further use of the SimMechanics library. To select the coefficients, a quadcopter control system is also implemented to the Simulink project, the signals from one sent to the motors in accordance with their physical location. The result of the article is a flight visualization of a 3D model of a quadcopter with a control system implemented in Simulink.

Keywords: solidworks, matlab, simulink, quadcopter, uav, pid, simmechanics

The paper calculates the probability of failure-free operation of parts of the supporting structure of foreign-made lifting equipment designed to perform loading and unloading operations of stone building material. When performing calculations, computer modeling of the stress-strain state by the finite element method was used. A distinctive feature of the proposed calculation methodology is the minimum required number of computer experiments, given that some of the input data are variable.

Keywords: probability of failure-free operation, lifting equipment, reliability

Currently, loaders for piece loads used in the technological process of loading-transporting and laying barrels of oil are widely used in industry. In particular cases, during loading and transport operations, the functionality of the loader is sufficient, but when laying cargo or obstacles occur, it is necessary to maneuver using the loader chassis, which significantly increases the execution time of the technological process. The results of the conducted studies have shown that when performing the technological operation of capturing, transporting and stacking barrels, the time to move the chassis is up to 12%, while the loader performance coefficient is 0.65. Numerical modeling of the positioning process of the load-handling body of the output link of the loading and transport unit is carried out, on this basis, a loader design based on a stacker is proposed and developed. The degree of mobility of the manipulation mechanism is calculated.

Keywords: numerical modeling, loader, manipulator, hinges, chassis, structural analysis, degree of mobility, kinematic analysis, service area, lifting body, mechanism

There are now many reasons why training in artificial intelligence (AI) technologies can be important for today's students. Therefore, AI-related disciplines are actively included by universities in undergraduate and graduate programs. It is important to teach students to understand how such technologies work and how they can be used to solve various problems. In turn, training is unthinkable without demonstrating examples of solving various problems. An important step in solving the problem of machine learning in general, incl. task of computer vision, is the stage of formation of the training sample. Therefore, the idea arose of writing a program that would be able to generate datasets on various topics for computer vision tasks. The data format of the generated sample for training train.csv is generally accepted and looks like this: each line is a description of one image; the first column contains the class labels to which the image belongs; the remaining columns contain the pixel values of the image, for example as a flat vector, where each value corresponds to the brightness of a corresponding pixel in the image. The resulting datasets can be used to organize the project activities of students on artificial intelligence.

Keywords: artificial intelligence, machine learning, computer vision, neural network, training set, dataset, C#, pixel, subpixel image processing, organization of student project activities

In this study, the thermal properties of porous materials with the topology of triply periodic minimal surfaces (TPMS) of Schwarz are investigated. By generalizing the results of computational experiments, the dependencies of the thermophysical properties of TPMS materials on macrostructural parameters such as size and thickness of the elementary cell have been obtained. The properties of the most common thermoplastic polymers PETG, ABS, PLA, and PHP used in additive manufacturing have been explored. It is demonstrated that the thermal conductivity coefficients of the examined TPMS materials can be represented as a linear function of the dimensionless geometric parameter – the relative thickness of the elementary cell wall. By varying this parameter, and consequently the geometric structure of the porous medium, it is possible to obtain a material with desired thermophysical properties. Verification of the obtained finite element method results is conducted based on the analysis of mesh convergence of solutions.

Keywords: effective thermal conductivity; heat transfer; porous material; porosity; thermoplastic polymer; ordered macrostructure; Schwarz minimal surface; triply periodic surface

The possibilities of a little-studied method for obtaining nanosized materials of electronic engineering with a given substructure, the zone sublimation epitaxy (ZSE) method, are discussed. In the work, it is combined with the method of gradient liquid phase epitaxy (GLE). A specific feature is mass transfer in a two-phase medium (a solid substrate and an inert gas phase acting as a transport medium) with preliminary deposition of a matrix layer formed from the melt. A feature of the sublimation process in the study was the crystallization of low-melting iron-silicon eutectic. A mathematical model of the process was proposed and compared with the experimental results. Island structures of the composition silicon (more than 90%), iron (up to 8%) and chromium (about 1.5%) have been obtained. Their parameters and size distribution were studied. A Solver-HV scanning probe microscope and a Quanta-200 scanning electron microscope were used. The study shows that the use of sublimation transfer transients makes it possible to reproducibly form doped silicon nanolayers and transform them into regular mesostructures.

Keywords: microsize growth cell method, zone sublimation epitaxy, gradient liquid phase epitaxy, island nanostructures

The article discusses the importance of using computer modeling to analyze the technical and operational characteristics of products, identify possible failures. The paper presents the results of a study of the operational conditions of a threaded connection, and draws conclusions about the effectiveness of using the ANSYS software in the design of mechanical engineering products.

Keywords: threaded connection, modeling, innovative technologies, optimization, safety margin, performance characteristics, thread pitch, mechanical engineering

Forecasting the consumption of electrical energy and power is an urgent and significant problem. This paper discusses current methods for predicting the consumption of electrical energy, reflected in various scientific papers, their analysis is carried out with the identification of more promising forecasting methods.

Keywords: energy consumption forecasting, statistical forecasting methods, neural network forecasting methods, hybrid forecasting methods

Electrocardiogram signals have unique characteristics and structure that are difficult to fake. This is due to the fact that the electrical activity of the heart is unique for each person. In addition, the main biometric parameters are hidden during ECG authentication, which makes the process more secure and protected from counterfeiting. The purpose of this study is to evaluate the effectiveness of neural networks for ECG authentication for signals with non-periodic cardiac arrhythmias. The Siamese neural network has been developed as a model. The stages of preprocessing of ECG signals taken from the MIT-BIH database are also described. The model presented in the paper has achieved the following results. Accuracy: 99.69%. Sensitivity: 99.43%. Specificity: 99.94%. ROC-AUC: 99.69%. The results allow us to conclude that the proposed model can effectively authenticate users who have non-periodic cardiac arrhythmias, provided at least a small number of registered standards with violations.

Keywords: biometric authentication, ECG, Siamese neural network, convolutional neural network, Euclidean distance, ROC analysis

Constant force supports are used in all gas and oil refineries in cases where it is necessary to provide the mobility of the pipeline at the attachment points. The article discusses the algorithm for calculating the shape of the support profile details, which has a certain design. These details provide the constancy of the pipeline support vertical force when it is transferred from the compression spring to the support point. Analytical and geometrical variations of calculation are given. The article will be useful to specialists involved in the design of pipeline supports.

Keywords: movable joint, geometric calculation, variable stiffness, lisega, import substitution

This article implements an algorithm for recognizing the markings of a freight container based on deep neural networks. The main advantage of the proposed algorithm is the absence of the need for additional image transformations for marking localization and character segmentation. The EAST algorithm was used to solve the localization problem. To recognize the owner code and serial number of the container, Faster R-CNN Resnet 50 neural network models were trained. As a result of assessing the accuracy of the algorithm, appropriate conclusions were made, and possible options for improving the algorithm were formulated.

Keywords: machine learning, algorithm, cargo containers, neural network, image classification, recognition

A structural model of an intelligent classifier of unstructured textual data according to the degree of confidentiality is presented, which is a two-level cascading ensemble of classifier models. The meta-model of a fully connected neural network architecture, which has the greatest impact on the classification efficiency, is highlighted. The multi-criteria task of configuring the intelligent classifier is decomposed into the task of selecting configurable hyperparameters of the meta-model and the task of selecting their values. Taking into account the selected hyperparameters of the neural network meta-model, the multi-criteria task of selecting hyperparameters to be configured is presented in the form of a hierarchy that includes the goal, criteria and alternatives. A method for selecting configurable hyperparameters of an intelligent classifier of unstructured text data by the degree of confidentiality based on the hierarchy analysis method has been developed.

Keywords: DLP system, unstructured text data, intelligent classifier, hyperparameters, hierarchy analysis method

The paper considers a model problem of a combined thermal and diffusion process in silicon. The mathematical model of this process is an initial-boundary value problem for a system of linear partial differential equations of parabolic type. In this system, one equation describes the process of heat propagation in silicon, and the other describes the process of impurity diffusion in it. In this case, the equations are not independent in the same way that the diffusion coefficient depends on temperature. For each equation in this system, the corresponding initial-boundary conditions are set. An implicit difference scheme and the classical sweep method are used to find an approximate solution to the problem that has arisen. The paper presents a description of a numerical algorithm and exact calculation formulas for solving a discretized parabolic problem.

Keywords: model of thermal diffusion process, numerical simulation, sweep method, implicit difference scheme

The main characteristics of the building for dynamic calculation are the frequency and forms of natural oscillations. These values are related to the rigidity of the building, the rigidity of the elastic foundation and its mass. To study the effect of the stiffness of the elastic foundation, an equivalent idealized model of free oscillations of a cantilever rod is considered. The calculation takes into account the rigidity of the support. For the considered model, a transcendental equation and its numerical solution is obtained. Solutions for the limiting cases of elastic foundation stiffness are obtained. The obtained results allow us to analyze the effect of the stiffness of the elastic foundation on the frequencies of natural oscillations. It is calculated that with an increase in the stiffness of the elastic foundation, the frequencies of natural oscillations increase. The influence is limited and has an asymptotic character. The rigidity of the elastic foundation can have a significant effect on the natural frequencies of the first five bending forms of natural oscillations and may not be taken into account for higher-order forms.

Keywords: dynamics, natural oscillations, natural frequencies, building, structure, transcendental equation, elastic foundation, elastic support

The article analyzes the shaping of buildings and structures in modern architectural practice. Form in architecture is primarily a means of expressing and translating concepts. It's also what ultimately fills and divides the space we live in. Form in architecture can have great symbolic and cultural significance and can transform a space for the better or for the worse. The simplest of the forms are known as primary forms. The main shapes include circles, triangles and squares. Each form can be created by a combination of basic forms. When rotated or expanded, basic shapes can create three-dimensional volumes known as basic bodies. In modern architectural practice, it is very common to resort to the use of complex shapes created using spatial curves. The task of the architect is a complete visual representation of such forms in drawings, as well as using modern software graphics packages. The article raises the problem of the correct interpretation of architectural forms formed by such spatial curves (using the Hilbert curve as an example).

Keywords: architecture, spatial curves, axonometric projections, Hilbert curve, modernism, shaping, ornamentation, space

The article presents and substantiates the structure of the original combined pathospecific measuring device for the diagnosis of glaucoma, which will allow for a comprehensive analysis of the hydro- and hemodynamics of the eye and thereby improve the quality of glaucoma diagnosis. Based on this structure, a detailed metrological analysis of this installation as a means of biomedical measurements was given in the work. Brief conclusions on the work are given and prospects for the further development of the project are determined.

Keywords: combined pathospecific measuring device, tonometry, rheography, sphygmography

Methods for determining the position of the center of gravity and the static stability margin of an aircraft in flight are considered. Based on the analysis of the motion of an aircraft as a rigid body, possible methods for determining the position of the center of gravity are determined and their errors are calculated. Comparison of the errors of various methods made it possible to conclude that it is expedient to use a method based on the use of information on the fuel reserve.

Keywords: center of gravity, moments of inertia of the aircraft, free vibrations, fuel consumption

In the article, a mathematical model of the oscillations of an aerodynamic pendulum in the flow of a moving medium is constructed and investigated. As a model of the effect of the medium on the body, the model of quasi-static flow around the plate by the medium is adopted. According to this hypothesis, the aerodynamic forces acting on the body are applied at the center of pressure. In our problem, the pressure center is movable relative to the plate. The equations of motion for the body under consideration are obtained. The transition to new dimensionless variables has been carried out. The violation of uniqueness in determining the angle of attack at points where the air velocity of the pressure center is close to zero is shown. Envelopes for some areas of ambiguity are constructed using multiple solutions of algebraic nonlinear equations derived from kinematic relations. To do this, the coordinates of the return points are determined, the solution of the equations themselves is found, and the boundaries of the areas of ambiguity are depicted. In the mathematical package MATLAB 18, a program is written that.

Keywords: body, ambiguity area, envelopes, return points