Izvestiya MGTU MAMI

BACKGROUND: The production of complex aircraft engine parts, such as compressor and turbine wheels, using traditional machining methods is a labor-intensive and time-consuming process. Technological limitations, such as temperature deformations and the need for subsequent high-precision machining of critical surfaces, arise when using additive technologies for their manufacturing.

AIM: Development and justification of an integrated design and technological approach to the production of compressor and turbine wheels of a micro turbojet engine combining additive technologies and mechanical post-machining.

METHODS: The study examines structural elements to compensate for negative temperature effects, special supporting structures, elements for subsequent precise datum setting at a computer numerically controlled five-axis machine, allowances for post-machining. In addition, the study shows the technology of post- machining, including the preparation of machining datum surfaces on a universal machine, CAD preparation of the machining project, selection of tools, tooling and cutting modes, machining the final shape of the blades at a five-axis milling machine.

RESULTS: An integrated approach including design and technological solutions has been developed. A comparison of the labor intensity of the proposed and traditional production methods is carried out, showing a reduction in manufacturing time. Quantitative results of roughness measurement on critical surfaces after finishing are presented.

CONCLUSION: The practical value of the study lies in proving the applicability and effectiveness of the developed approach for the mass production of complex aircraft engine parts. The completed study and proposed solutions make it possible to overcome the key limitations of additive technologies and to ensure the manufacturing of products with high quality and precision properties.

BACKGROUND: An important parameter for oil well pumps is the inlet gas content in the pumped liquid before entering the pumping module. Exceeding the permissible gas content leads to a decrease in the pump pressure and disruption of the supply. Improving the designs of gas separators is necessary due to the increase in the proportion of wells with a large gas factor. To improve the designs with their increasing complexity, a promising method is the use of CFD (Computational Fluid Dynamic) modeling, which is capable of taking into account all the non-linearities of geometry completely.

AIM: Development of a calculation method for improving the design of a centrifugal gas separator based on CFD modeling of a multiphase flow.

METHODS: This study uses a numerical simulation method based on solving discrete analogues of the basic equations of fluid dynamics and multiphase flow.

RESULTS: The mathematical model is defined on the basis of verification with bench test results. The model is used for optimization of the separation drum length leading to improvement of weight-and-size properties of the gas separator.

CONCLUSION: Based on the results of the study, it can be argued that the proposed design of the gas separator in terms of separation efficiency, according to the developed mathematical model, is not worse than the original design, but has better weight-and-size properties.

Current trends in the development of the automotive industry are aimed at improving energy efficiency, environmental friendliness and safety of vehicles. One of the key directions in this area is the development of all-wheel drive electric vehicles with individual electric drives. This architecture allows not only improving the dynamic characteristics of a vehicle, but also implementing complex control systems such as torque control in order to adjust cornering and to increase directional stability. In English-language sources, such systems are called Torque Vectoring (TV). These systems can significantly improve its stability and handling, especially in difficult road conditions such as icy or wet surfaces.

The aim of the work is a comparative analysis of various controllers used to control the torque in electric vehicles with individual electric drives for the left and right wheels.

This paper considers various approaches to torque control, including both classical control methods such as controllers, and more advanced control methods such as first- and second-order sliding control modes, integral sliding mode, and fuzzy logic controllers. In addition, the paper discusses the control errors that are used to generate the torque, such as the yaw rate, the side slip angle, and the ratio of the axles’ velocities.

The paper contains an in-detail description of the principles of operation of each of the controllers, their advantages and disadvantages are noted, attention is directed to the problem of “rattling” in sliding modes and scenarios of incorrect control by error of the axles’ velocities. To assess the effectiveness of control methods, a weighted control efficiency index was used, which takes into account the accuracy of tracking yaw rate, minimizing the side slip angle, and the degree of control action.

It was found that most of the published assessments of the effectiveness of the proposed control methods were based on simulation results. Therefore, a need for further research, including tests on real vehicles and an assessment of the impact of the rattling effect on the operation of electric drives, remains.

The paper is a scientific review of unmanned aircraft systems (unmanned aerial vehicles, or drones) specializing in various types of cargo transportation. The development of the use of unmanned aircraft systems in postal and cargo logistics is presented, the main requirements of legal regulation and infrastructural requirements for the operation of drones are given, the influence of external factors and the social aspects of drone operation are described. An analysis of their practical application in various industries is given: agriculture and forestry, fisheries, wildlife protection, various types of environmental monitoring (including air quality control), mining, defense and civilian sectors, space industry, as well as during search and rescue missions. The tasks of Arctic exploration using drones are highlighted. The paper includes a historical review of the development of unmanned technologies, a description of Russian and international standards, classifications and categories of unmanned aircraft systems. In addition, the key advantages and limitations of unmanned systems are disclosed, as well as specific problems associated with the mail delivery by drones. The prospects of using unmanned vehicles are given. The main stages of scientific and technical development of unmanned systems are given. Unmanned aerial vehicles continue to evolve, and the next paper will cover the classification and development process of unmanned aerial vehicles.

BACKGROUND: The application of windshield wipers with independent electric drive allows eliminating the mechanical connection between them out of the vehicle design, freeing up space for installing various equipment. In this case, the electric drive control system is required to coordinate the motion of the windshield wipers in order to eliminate or prevent their intersection. Such an electric drive must have performance characteristics that meet standards and use standard hardware, in particular, sensors and an on-board electrical network.

AIM: Modernization of the previously developed control system for panoramic windshield wipers with an independent electric drive, intended to increase the frequency of their continuous cyclic motions while maintaining the composition of the hardware and basic operating principles.

METHODS: To modernize the electric drive control system of windshield wipers, methods of system analysis, software development and debugging methods, as well as experimental research methods were used.

RESULTS: Analysis of previously applied technical solutions showed that the coordination algorithm with opposite motion of windshield wipers leads to deep control of voltages feeding individual electric motors and, consequently, to a significant reduction in their values averaged over the motion cycle. Therefore, to increase the frequency of continuous cyclic motions of windshield wipers with independent electric drive, their antiphase motion is used with the original algorithm of coordination implemented in software without any change of the hardware parts. The use of reversible power converters feeding electric motors allows the windshield wipers to be brought out of positions that lead to intersection without reversing the direction of their rotation.

CONCLUSION: The modernized control system of independent electric drive of windshield wipers has demonstrated the fundamental achievability of the frequency of their antiphase continuous cyclic motions on a bus windshield that meets the standards.