This paper series presents a study on the nonlinear dynamics and adaptive control of the guidance (GG) with a fast astatic gyroscope in external gimbal suspension (GAR), using the concept of dynamic inversion and neural networks. In part 1, a new nonlinear dynamic model is derived for the GG placed on an aircraft (rocket), which expresses the GG dynamics relative to the absolute trihedron; generalized Euler equations are used for its dynamic elements (rotor- inner gimbal assembly and outer gimbal). The absolute angular velocities of the GG's dynamic elements have as components their angular velocities relative to the trihedron linked to the guidance line, and the perturbing angular velocities induced by the rocket's angular velocities around its axes. The obtained nonlinear equations are then expressed in equivalent forms, where the new variables are the angular rotation velocities of the guidance line (the target coordinator axis, i.e., the gyroscope's proper angular momentum axis). The angular rotation velocities of the guidance line are chosen as the output variables of the GG, with respect to which the relative degrees of the equations are equal to 2. The input variables of the nonlinear dynamic model are the command currents applied to the command coils of the motors located in the axes of the two gyroscopic gimbals, which create, by gyroscopic effect, correction angular velocities the orientation of the target coordinator axis (guidance line) in the direction of the target line. The obtained equations contain terms that are functions of the input and output variables, as well as terms that are functions of the transport angular velocities of the guidance line and perturbing terms (functions of the rocket's angular velocities).
The aerodynamic terminological field is characterized by highly complex and specific terms which are used to describe various scientific phenomena that occur during flights. The aim of the paper is to analyze aerodynamic terminology using a frame semantics approach to study terms categorized into frames and subframes. The study reveals the linguistic behavior of aerodynamic terms within the frames. Using the corpus linguistic software Sketch Engine, we identified recurring patterns, collocations, and term frequency in a compiled corpus of books on aerodynamics. The findings reveal that aerodynamic terminology can be systematically structured into frames, which can overlap, thus demonstrating the conceptual construction of complex, technical meanings of the aerodynamic terms. The research contributes to a better understanding of aerodynamic terms as part of the aviation terminological field and is of great help to people interested in learning, teaching, and working in the field of aerodynamics.
The article presents two methods for assessing students' achievements in the National External Assessment in Mathematics after the 7th grade in Bulgaria. Some advantages of analyzing the assessment using Item Responsibility Theory are shown.
In the last decade it became obvious the need to provide fast manufacturing technologies and to reduce parts costs for the aeronautical industry in general and for the rapidly developing flying drones segment. This demand led to the development of new technologies and materials like CFRP and GFRP composite materials, but also additive manufacturing (3D Printing) using different metallic compounds or thermoplastic materials. In this paper is presented a study related to the possibility of using these new 3D printing materials and technologies in the aeronautical industry (light aircrafts and drones), with emphasis on the reduction of costs versus weight. The main goal of the study is to find if fast printing thermoplastics like ABS, PLA or PETG are acceptable from a design and stress point of view.
The paper discusses an approach to implement an effective contribution of the Rakovski National Defence College (RNDC). The aim of the study is to contribute to the overall efforts to increase the resilience of the national security system of the Republic of Bulgaria. The strategic documents that form the framework of this publication and define the definitions related to the topic of resilience of the national security system are examined. Presented are the main requirements for national resilience contributing to NATO's collective capability in this area.
The article will analyze the types of missiles that can be attached to the IAR 330 Puma SOCAT helicopter, compatible with its modern avionics and armament system. The key element is the presentation of the missiles that Rafael has designed, compatible with this type of helicopter, and finally a multi-criteria analysis will be performed based on their characteristics. The study will highlight the best existing constructive variant of the missiles that are compatible with the SOCAT system.
The paper deals with a planar supersonic air inlet with variable inner cross-section, equipped with a fixed geometry centerbody. Its optimal architecture is determined and possible control laws are studied. A control system was presented and modeled, based on the inlet’s inner minimum cross-section opening control with respect to the flight regime. System’s quality was estimated by some Matlab-Simulink simulations; control system’s step response(s) for different flight regime’s step input(s) were evaluated, which has permitted important conclusions, discussions and comments to be presented, concerning embedded system’s properties an quality.
The military potential of any state is determined primarily by its economic capacity, by the endowment of military structures with modern combat equipment and technology, as well as by the level of training of the combat forces. It can also be stated that the economic, financial, social, diplomatic and political dimensions as components of national security are achievable only by ensuring efficient management, integrated both at the organizational and national levels. Currently, most states are marked by permanent transformations, unpredictability, rapid changes and challenges in all areas, management thus becoming an essential tool for the efficient organization and implementation of diverse and complex projects. I believe that an adequate and applicable management model for the military organization is project management, which can be considered an essential component in the successful strategies of units and large units.
Beginning with how a top secret agency (SOE) accomplished its dangerous task during World War II of coordinating subversion and sabotage against the enemy by any means necessary - using disguise, deception, bribery, explosives (sometimes disguised as objects such as a dead rat or a bottle of chianti) guerrilla warfare - and even assassination, the research highlights the crucial role of information in national security and how information has been strategically used to influence decisions, manipulate perceptions and gain advantage in a variety of areas, from military warfare to economic and political competition. The research also highlights that in the context of globalization and technological advancement, information has become a key strategic resource, as important as material or human resources. The ability to control the flow of information, to disseminate correct information or misinformation and to protect one's own information has become a determining factor in the success or failure of any strategic action. Thus, the research highlights the various forms of the use of information as a weapon such as information warfare, media warfare, cyber warfare, electronic warfare, influence operations, counterintelligence and emphasizes the importance of developing robust national information security strategies that include measures to protect, detect and respond to information threats. It also emphasizes the need for public education on information literacy and resilience to disinformation. In conclusion, the research demonstrates that information has been and is a fundamental component of power, and understanding and strategically managing it is essential for the security and prosperity of any entity, be it state, organizational or individual. It also, in this context, emphasizes the need to train specialists capable of understanding the importance, effectively managing and properly using this ”weapon” - information.
The article presents a structural analysis of the malfunctions of the gas turbine engine AI-25TL based on statistical materials from its maintenance in the Bulgarian Air Force. The reporting and collection of information on the malfunctions of aircraft engines makes it possible to establish the nature of their manifestation and the degree of their recurrence. Based on mass observations of the occurrence and manifestation of various malfunctions, measures are developed and implemented aimed at increasing the level of reliability of aircraft engines.
In this article I will try to address the encrypted form of transmission using Hamming encoding on a Raspberyy Pi Pico W platform. I chose to test on a PiPico platform because it offers computing power comparable to that of a microcomputer and allows easy programming in Python.
The increasing air traffic at Romanian airports in recent years has necessitated a heightened focus on aviation safety standards. Simultaneously, climate change has altered the frequency of meteorological phenomena that impact aviation activities. This study aims to establish a baseline climatology and identify evolving trends of hazardous weather phenomena for the main airports in Romania between 1941 and 2022. The study uses ERA5 data to derive the most important parameters to study the occurrence of thunderstorms, low-level wind shear, reduced visibility, and snowfall, the weather phenomena that are relevant for the air traffic safety. The results show an increase in the number of hours with thunderstorms in the eastern part of the country and a rising trend in events with low-level wind shear in the western and central regions. Conversely, events with significant snowfall are decreasing in the eastern Carpathians and Muntenia region, while those with limited visibility are decreasing in the coastal regions and northeastern Romania. These findings can inform aviation safety regulations and help mitigate the impact of hazardous weather conditions on aeronautical activities.
The road accidents are still part of our daily lives in an unwanted way and, in order to resolve the various resulting disputes, they need to be investigated in detail. If the investigation methods based on testimonials or/and visual observation are accessible even to amateurs, they also reveal a lot of subjectivity. The most reliable, professional and "cold" method of analyzing a traffic accident remains the scientific one based on the mathematical apparatus and studies specific to the field of accidentology science. We are going to present a possibility to apply the energy conservation theorem in the case of an road accident where we will attempt to thoroughly detail all the energies resulted from the impact.
Introducing combined alarm systems for Romania flood zones is critical for constructing a disaster response as well as for people’s safety. Communication, evacuation and flood relief involve advanced technology. Image processing also facilitates assessment of flood impact on roads, bridges and other infrastructures. By using AI in algorithms across large datasets organizations can upgrade their operations and decision-making in real-time. The concerns of rehabilitation can therefore be helped by AI to assess the floods in the infrastructures and hasten its rehabilitation process. Moreover, the AI generated models can actualize flood scenarios hence enabling the authorities improve their preparation for different levels of floods. It aids in identifying the data and off-loading it which makes flood control more effective and intelligent. These smart sensors with the help of AI may assist communities in getting the first warning and preventing the situations. The use of actual data as the basis of simulations and real- time data gathering may enhance existing evacuation plans so that authorities can better organize those routes and make faster decisions with better information. These integrated solutions might help to improve the existing technical infrastructures aimed at the prevention and management of floods in Romania by improving preparation and assessment of flood hazards and disasters. The implementation of real-time gathered data alongside actual data from simulations can improve current evacuation strategies by helping authorities better manage evacuation paths and respond through more informed choices.
Ion propulsion, traditionally utilized for adjusting satellite and space station trajectories, also holds considerable promise for aeronautical applications. This paper explores the viability of an ionic wing designed to ionize atmospheric air using a grid-based system thus eliminating the necessity for external gases such as xenon. The proposed wing features a rectangular configuration equipped with multiple grids, enabling selective application of electrical voltage to facilitate controlled tilting and directed flight maneuvers. Preliminary propulsion calculations are presented, linking voltage requirements to achievable speeds and the resulting thrust. These findings contribute to developing an aircraft model capable of self- propulsion without reliance on fossil fuels, highlighting the potential to replace conventional kerosene-based propulsion with simpler, more cost-effective, and environmentally sustainable alternatives.
The specific applications of atmospheric and environmental data acquisition are found in the following areas: air quality monitoring, climate and meteorological studies, extreme events (volcanic eruptions, fires, and floods), biodiversity, waste and soil pollution, precision agriculture (crop monitoring). The paper proposes an applicative approach regarding the monitoring and acquisition of atmospheric and environmental data with the help of open source hardware tools (arduino platform) on board a customized UAV, as a low-cost functional model, with educational and research use.
Modern higher education is no longer limited to the preparation of narrow specialists for a specific field of activity, but to the development of the personality of each student, increasing his professional competence and effectiveness and above all creating proactive and motivated citizens who participate in public life. The emphasis is shifting from learning large amounts of information to learning ways of continuously acquiring new knowledge and learning skills; forming habits of independent (creative) rather than reproductive thinking.. The new educational paradigm is a strategy of education for the future, its essence being the transition from mastering the volume of information to developing critical thinking, learning to solve problems and actively working with information in an increasingly complex world This paper looks at the revised approaches to education, which is seen as a process of knowledge creation resulting from the application of research methods, rather than as a process of mere knowledge and skills transfer. The main characteristic of knowledge is its timeliness and relevance - the learner learns it not because the curriculum requires it and not because it is necessary to know it, but because this knowledge allows to solve real problems in real conditions of activity. In this way, learning becomes practically oriented and evolves into lifelong learning.
This paper presents an applied study for topological optimization, a modern engineering design technique that aims to optimally distribute the material in a given area, in order to obtain a structure that is as light and mechanically efficient. The first part of the paper analyzes the general concepts of topological optimization, such as the basic principles, common constraints and objective criteria used in engineering applications. The case study focuses on an aircraft cargo floor strut, a structural element frequently encountered in aeronautical applications. The optimization was performed using the OptiStruct solver developed by Altair Engineering, which offers advanced structural analysis and optimization capabilities. The pre- processing and boundary condition definition steps were performed in HyperMesh, while the analysis of the results and visualization of the optimal material distribution were performed with HyperView. The obtained results demonstrate a reduction in the mass of the component, while maintaining structural performance within the specified limits, thus validating the efficiency of the method used in the optimized design process.
In the contemporary geopolitical landscape, characterised by instabilities, climate change, and mounting cyber threats, the pursuit of energy independence has transcended the realm of mere political aspirations, becoming a matter of strategic imperative. Recent events in Spain and Portugal, where a substantial blackout impacted critical infrastructure and communications, underscore the vulnerabilities of centralized and interdependent energy networks. This incident has led to a resurgence of interest in the necessity for local, sustainable, and secure energy solutions, particularly in regard to critical infrastructure. Such infrastructure may include hospitals, data centres, communication networks, public transport, and defence systems. The solutions are varied, but must be chosen in relation to the available and potential resources and infrastructure, and especially the level of importance of the objectives to be protected.
This paper presents the design of the adaptive control system of GG with GAR, consisting of a stabilization controller and an orientation controller; the concept of dynamic inversion is used. The equations of nonlinear dynamics of GG were obtained in Part 1 of this paper series.The stabilization controller (for the stabilization mode) consists of a 2nd order reference model, a linear dynamic compensator, of the P.D type, a linear state observer and a neural network. The neural network models the adaptive component of the control law, which has the role of compensating for the dynamic inversion error. The orientation controller is chosen as P.I. type. In stabilization mode, the system compensates for the effect of external disturbances induced by the rotations of the base (rocket), and in orientation mode, the system controls the rotation of the target coordinator TC so that the sighting line (TC axis) overlaps the guidance line. By numerical simulations, using the Matlab/Simulink model, the dynamic characteristics of GG are drawn for the stabilization mode and for the orientation mode
