Type UAV Research Articles

Design and implementation of a nonlinear observer for a novel Quadrotor UAV: the HELIPLANE

This study presents the design and dynamic modeling of a new type of quadrotor UAV, referred to as the Heliplane, which integrates the vertical take-off and landing (VTOL) capabilities of a multirotor with the horizontal flight efficiency of a fixed-wing aircraft. The modeling process involved creating a dynamic representation of the Heliplane, with special attention to the determination of its aerodynamic coefficients, which were calculated using SolidWorks Flow Simulation. The aerodynamic forces, including lift and drag, were analyzed based on the flow characteristics around the Heliplane's structure. To further enhance the system's performance, a nonlinear observer based on a sliding mode approach was synthesized. This observer was designed in a triangular form to ensure accurate state estimation and robust control, even in the presence of model uncertainties. The observer's key advantage lies in its finite-time convergence, which guarantees quick and precise tracking of the Heliplane's state variables. Simulation results demonstrated the effectiveness of the proposed observer in estimating the rotational and translational velocities with minimal deviation. The sliding mode observer's performance suggests its suitability for control and fault detection tasks in UAV applications, particularly in challenging operational environments.

Wind Tunnel Investigation of the Icing of a Drone Rotor in Forward Flight

The Bell Textron APT70 is a UAV concept developed for last mile delivery and other usual applications. It performs vertical takeoff and transition into aircraft mode for forward flight. It includes four rotor each with four rotating blades. A test campaign has been performed to study the effects of ice accretion on rotor performance through a parametric study of different parameters, namely MVD, LWC, rotor speed, and pitch angle. This paper presents the last experimentations of this campaign for the drone rotor operating in forward flight under simulated icing conditions in a refrigerated, closed-loop wind tunnel. Results demonstrated that the different parameters studied greatly impacted the collection efficiency of the blades and thus, the resulting ice accretion. Smaller droplets were more easily influenced by the streamlines around the rotating blades, resulting in less droplets impacting the surface and thus slower ice accumulations. Higher rotation speeds and pitch angles generated more energetic streamlines, which again transported more droplets around the airfoils instead of them impacting on the surface, which also led to slower accumulation. Slower ice accumulation resulted in slower thrust losses, since the loss in performances can be directly linked to the amount of ice accreted. This research has not only allowed the obtainment of very insightful results on the effect of each test parameter on the ice accumulation, but it has also conducted the development of a unique test bench for UAV propellers. The new circular test sections along with the new instrumentation installed in and around the tunnel will allow the laboratory to be able to generate icing on various type of UAV in forward flight under representative atmospheric conditions.

Research on Combat Mission Configuration of Unmanned Aerial Vehicle Maritime Reconnaissance Based on Particle Swarm Optimization Algorithm

In recent years, in the classic battles and armed conflicts around the world, battlefield environment reconnaissance and the collection and processing of operational information play an increasingly critical role in the victory and defeat of the battlefield. Unmanned equipment, especially UAV equipment, is used by more and more countries in the field of combat reconnaissance. Meanwhile, the types of UAV are gradually diversified with the change of operational requirements. UAVs adapted to different combat environments shine brightly on the battlefield. In terms of naval battle field, due to the limitations and deficiencies of reconnaissance methods such as surface radar, UAVs play a more prominent role in combat reconnaissance. There are more scenarios for UAVs to be used in combat reconnaissance in naval battle field and higher requirements for UAVs’ combat effectiveness. Therefore, this paper takes UAVs’ naval battle reconnaissance missions as the research object. By using PSO as the research method, this paper studies the combat reconnaissance task configuration of UAVs, hoping to contribute to the improvement of UAVs’ combat reconnaissance capability and combat effectiveness.

Unmanned aerial systems for biological plant protection based on UAV type CE-20

The article presents an analysis of the use of UAVs of the CE-20 type as part of unmanned aerial systems for biological plant protection. The relevance of the study is determined by the intensive development of modern unmanned technologies used to combat insect pests and plant diseases. The proposed analysis of modern practice of using UAVs of the CE-20 type for biological plant protection will reveal the relationship of technical characteristics with agrotechnological methods. This will provide effective technical support for unmanned aerial systems applications in precision agriculture. It is important to consider that the characteristics of the UAVs used significantly influence the process of spraying fertilizers and pesticides. The article analyzes the previously obtained results of test flights of the CE- 20 of the Chinese company Wuxi Hanhe Aviation Technology. Testing was carried out taking into account a given field cultivation strip, on which the effective spray width of fertilizers and pesticides was determined and studied. The obtained droplet deposition coefficients of variation showed good deposition uniformity and penetration rate. It is shown that optimization of UAV parameters must be combined with agronomic requirements based on the choice of crop types, growth period, pest and disease characteristics, and environmental conditions.

Study of the influence of turbulent flows on the aerodynamic performance of fixed-wing aircraft type UAV MALE

A study of the air behavior in the near-wake region of the NACA0012 airfoil infinite wing model at low Reynolds numbers was conducted. The study consisted of comparing the results obtained from experiments with those from numerical simulations. The numerical results of the velocity profiles in the near-wake region showed good agreement with those provided by the PIV system for most of the simulations and those in the literature. In addition, boundary layer separation and reattachment forming a laminar separation bubble along the airfoil was captured using simulations in Ansys Fluent and compared with a literature database to better confirm the simulation results. The UAVs have a complex cross-section shape of the fuselage. The second part of this paper explores the aerodynamic consequences of its shape, at the operational flight ceiling, in a comparative approach for three different fuselage designs.

Productivity analysis of agricultural UAVs by field crop spraying

The article presents an analysis of the performance of agricultural UAVs when spraying field crops. Based on an analysis of the current state of technology for using UAVs in precision agriculture, a model for calculating UAV performance has been developed, based on the time structure of the crop spraying process, including the time of spraying, replenishment of mineral fertilizers or pesticides, and UAV flight. It is noted that for an agricultural UAV, when used in a precision farming system, the equation of existence must relate the take-off mass, the functional components of the take-off mass and the parameters of the sprayer, ensuring differentiated application of pesticides and fertilizers. Based on the proposed performance model of agricultural UAVs, recommendations are given for choosing the type of UAV for spraying crops. This model allows us to generalize methods for testing the production performance of agricultural UAVs, build models of production efficiency and provide proposals for technological solutions to improve these performance characteristics.

A novel aerodynamic layout design of composite wing unmanned aerial vehicle based on canard configuration

With the development of information technology and technology, more and more cutting-edge industries have come into view of the public, among which one of the most representative technologies is UAV. The emergence of UAVs has reduced the labor cost of some businesses, such as farming, forest fire prevention, maritime patrol and so on. In response to the common problems of long preparation time and poor maneuverability of unmanned aerial vehicles, this paper studies the aerodynamic layout of unmanned aerial vehicles and proposes a new layout. Firstly, the aerodynamic layout of typical UAVs is introduced and compared and analyzed. Then, a new type of compound wing UAV is designed by screening and analyzing the wing, flight analysis, main wing and UAV production process with Reynolds number. Subsequently, simulation experiments were conducted to analyze and optimize the aerodynamic layout performance of the designed UAVs, thereby verifying the reliability of the proposed method.. Finally, the entire content is summarized and analyzed.

A novel aerodynamic layout design of composite wing unmanned aerial vehicle based on canard configuration

With the development of information technology and technology, more and more cutting-edge industries have come into view of the public, among which one of the most representative technologies is UAV. The emergence of UAVs has reduced the labor cost of some businesses, such as farming, forest fire prevention, maritime patrol and so on. In response to the common problems of long preparation time and poor maneuverability of unmanned aerial vehicles, this paper studies the aerodynamic layout of unmanned aerial vehicles and proposes a new layout. Firstly, the aerodynamic layout of typical UAVs is introduced and compared and analyzed. Then, a new type of compound wing UAV is designed by screening and analyzing the wing, flight analysis, main wing and UAV production process with Reynolds number. Subsequently, simulation experiments were conducted to analyze and optimize the aerodynamic layout performance of the designed UAVs, thereby verifying the reliability of the proposed method.. Finally, the entire content is summarized and analyzed.

Material Optimization for Structural Strength of Hexacopter Landing Skid Using Finite Element Method

Hexacopter is a type of UAV that has six propellers with a load of 15 kg or about 147 N in this study. Then, to support the landing of the hexacopter and to support it while being on the ground, landing skid is needed. The landing skid is designed using 3D printing from selected materials to find out which material is best used for the landing skid, including PLA, PETG, and ABS. 3D-printing supports the production of lightweight and high-strength parts. This research method uses finite element to compare several materials and uses SolidWorks to simulate static load and drop test by landing skid. The results show that PETG material is the best material with the highest safety factor in the static load and has the lowest strain value in the drop test.

Aerodynamic Stability Study of Turbojet Engine During Unmanned Aerial Vehicle Assisted Taking Off Stage

Rocket Assisted Take Off (RATO) technology is utilized for the takeoff phase of various types of UAVs. RATO creates heavy axial overload for a UAV system, which consequently increases the inlet pressure of the fuel pump of the UAV’s turbojet engine. This situation leads to an abrupt change in fuel supply for its combustor, eventually causing drastic changes in the operating state of the compressor system. In addition, it may potentially induce compressor surge. To resolve this problem, through an experimental investigation, this study delves into the dynamic response of the fuel system during the RATO phase. A two-zone dual-wave coupled compressor model has been established for the intake-turbojet engine system to scrutinize the aerodynamic stability of the turbojet engine during the RATO phase. The findings reveal that when the increase of fuel pump inlet pressure causes changes in the fuel flow rate, it is essential for the engine to re-establish aerodynamic equilibrium in order to mitigate the impacts of abrupt fuel flow step increases. Moreover, it has been observed that the more the ratio of the length of the intake and the cross-section area, the greater the contribution of the inertial force of airflow in the pipe it brings within the passage. This results in a stronger suppression of combustion chamber pressure and flow rate fluctuations induced by fuel step supply, thereby rendering the compressor less susceptible to surge. In summary, this research contributes valuable insights for appropriate matching of intakes, enhancing the ability of the turbojet engine against fuel step supply in the combustion chamber during the takeoff stage and augmenting the aerodynamic and thermodynamic overload resistance capability of the engine.

Vibration Damper Design and Additive Manufacturing for Unmanned Aerial Vehicles

The main focus of this study revolves around the problem of vibrations in unmanned aerial vehicles and aims to propose solutions using different designs of vibration dampers. Specifically, the study identifies the sources of vibrations in a Single Rotor Rotary Wing (Monocopter) type UAV. To assess the damping performance of the designed dampers, vibration tests were conducted in a controlled setup. Based on the measurement results obtained at three different speed stages, a particular damper, referred to as G2S2, exhibited the highest damping performance. At the first speed stage, it achieved damping percentages of 66% for the X-axis, 77% for the Y-axis, and 84% for the Z-axis. At the second speed stage, the percentages increased to 81% for the X-axis, 84% for the Y-axis, and 97% for the Z-axis. Finally, at the third speed stage, the damper demonstrated damping percentages of 85% for the X-axis, 84% for the Y-axis, and 98% for the Z-axis. This study successfully developed an experimental setup for measuring vibrations during UAV flight, particularly focusing on unmanned aerial vehicles. Furthermore, among the vibration dampers produced using additive manufacturing techniques, the damper with the highest performance, namely G2S2, was selected. Considering the measurement results, G2S2 emerged as the most effective vibration damper. It is worth mentioning that this damper can also be tested in real flight scenarios in the future, building upon the outcomes achieved through the experimental setup.

Mathematical Models of the UAV Operators

Abstract The operators maintaining different kinds of activities might have different mathematical models regarding their physical and mental status, their skills and experiences, their level of training they own. Recent days more and more attention is paid to wide spread of different UAVs applied both in military and in non-military governmental applications. The UAV production industry is able to manufacture UAVs for different and diverging purposes. However, the effective maintenance of these UAVs requires highly trained and qualified operators. When massive UAV applications support combating ground forces in the war theatre the training of the UAV operators becomes to be one of the crucial criteria. Diversity of the UAV types often fabricated and gunned for military purposes shows difficulties of the training program created for UAV operators. This paper addresses mathematical models of the UAV operators applied both in open and closed loop control systems of the UAVs. Additionally, findings of this paper might support and improve selection process of the UAV operators to reach maximum efficiency of both military reconnaissance and combat applications.

JUSTIFICATION OF THE FEASIBILITY OF USING THE “AUDS” SYSTEM FOR COUNTERING UNMANNED AIRCRAFT DEVICES

The article investigates the effectiveness of using the “AUDS” system to counter unmanned aerial vehicles by summarizing research, testing and analysis of the current state of development of unmanned aerial vehicles and means of radio-electronic combat against them. The object of the study is the anti-UAV defense system “AUDS” (Anti-UAV Defense System), produced by the ECS company (Great Britain), which came as material and technical assistance to Ukraine from partner countries. In the course of Russian’s armed aggression against Ukraine, the widespread use of commercially available small UAVs, as well as UAVs of the barrage type, requires the protection of critical infrastructure, important facilities, and military units from their impact. The experience of conducting combat operations in modern wars has shown that the use of expensive air defense equipment against small and medium-sized UAVs is not always appropriate. Therefore, it is the radio electronic suppression (REP) systems that are able to effectively solve the task of countering the specified types of UAVs. The article contains recommendations for improving the “AUDS” system to increase the effectiveness of detection and radio electronic suppression of modern and promising unmanned aerial vehicles, including those produced by the Islamic Republic of Iran.

UAV Mission Path Planning Based on Reinforcement Learning in Dynamic Environment

With the rapid development of information technology, various products used in information technology are also constantly optimized. Among them, the task and path planning of UAV in the high-end robot industry has always been the focus of relevant researchers. In the high-end robot industry, in addition to the research and development of UAVs, they also continue to learn and strengthen the task and path planning of UAVs. Nowadays, using unmanned aerial vehicles for real-time shooting has become the trend of this era. Drones have brought great convenience to people’s lives, and more and more people are willing to use drones. Based on the above situation, this paper studies the task and path planning of UAV based on reinforcement learning in dynamic environment. In the case of unpredictable scene parameters, reinforcement learning method can be established by value function. Thus, a more reasonable path can be given to realize the reconnaissance and detection of points of interest. MATLAB simulation experiments show that the algorithm can effectively detect targets in complex terrain composed of terrain restricted areas, and return to the designated end point to complete communication. Firstly, the development of unmanned aerial vehicles in various countries and the social status of unmanned aerial vehicles are discussed. By making UAV build threat model and task allocation in dynamic environment. The path planning and optimization of UAV in dynamic environment is studied, and the path planning algorithm and Hungarian algorithm are added. The optimized UAV has the fastest data transmission and calculation speed, while the other two types of UAVs have slower data transmission and calculation speed. In particular, ordinary UAVs also have data transmission failures, resulting in incomplete experimental results. The results show that the optimized UAV system is better in data calculation and transmission, which also shows that the UAV can quickly plan and process flight paths, which is suitable for practical applications.

Adjustable Fully Adaptive Cross-Entropy Algorithms for Task Assignment of Multi-UAVs

This paper investigates the multiple unmanned aerial vehicle (multi-UAV) cooperative task assignment problem. Specifically, we assign different types of UAVs to accomplish the classification, attack, and verification tasks of targets under resource, precedence, and timing constraints. Due to complex coupling among these tasks, we decompose the considered problem into two subproblems: one with continuous and independent tasks and another with continuous and correlative tasks. To solve them, we first present an adjustable, fully adaptive cross-entropy (AFACE) algorithm based on the cross-entropy (CE) method, which serves as a stepping stone for developing other algorithms. Secondly, to overcome task precedence in the first subproblem, we propose a mutually independent AFACE (MIAFACE) algorithm, which converges faster than the CE method when obtaining the optimal scheme vectors of these continuous and independent tasks. Thirdly, to deal with task coupling in the second subproblem, we present a mutually correlative AFACE (MCAFACE) algorithm to find the optimal scheme vectors of these continuous and correlative tasks, while its computational complexity is inferior to that of the MIAFACE algorithm. Finally, numerical simulations demonstrate that the proposed MIAFACE (MCAFACE, respectively) algorithm consumes less time than the existing algorithms for the continuous and independent (correlative, respectively) task assignment problem.

Multi-objective Optimization Design of Solar UAV Overall Parameters

Based on the design background of solar UAV, this paper introduces the characteristics of this kind of UAV, such as high flying height, large wingspan, large structural deformation and low wing load. The mathematical model of multi-objective optimization for this type of UAV is established, and the multi-objective genetic algorithm is used to optimize the design. The optimization results of the aircraft design are obtained by computer. Finally, the summary parameters and basic design drawings of this kind of aircraft are given. The results show that multi-objective optimization can be used in the design of solar UAV, and the optimal combination of the overall parameters of this kind of UAV can be obtained to avoid design defects and improve design efficiency. After the optimization design, the overall performance of the aircraft has been improved. This method has a certain reference value for the design of new aircraft.

CW coherent detection lidar for micro-Doppler sensing and raster-scan imaging of drones.

We demonstrate a continuous-wave (CW) coherent detection lidar (CDL) capable of detecting micro-Doppler (propeller) signatures and acquiring raster-scan images of small unmanned aerial systems/vehicles (UAS/UAV). The system uses a narrow-linewidth 1550 nm CW laser and takes advantage of mature and low-cost fiber-optics components from the telecommunications industry. Using either collimated or focused probe beam geometry, lidar based detection of characteristic periodic motions of drone propellers up to a remote distance of 500 m has been achieved. Furthermore, by raster scanning a focused CDL beam with a galvo-resonant mirror beamscanner, two-dimensional images of flying UAVs up to 70 m range were obtained. Each pixel of the raster-scan images provides both lidar return signal amplitude and target radial speed information. The raster-scan images obtained up to 5 frames per second make it possible to discriminate various UAV types based on their profile and even resolve the presence of payloads. With feasible improvements, the anti-drone lidar is a promising alternative to expensive EO/IR and active SWIR cameras used in counter-UAV systems.

A Systematic Literature Review (SLR) on Autonomous Path Planning of Unmanned Aerial Vehicles

UAVs have been contributing substantially to multi-disciplinary research and around 70% of the articles have been published in just about the last five years, with an exponential increase. Primarily, while exploring the literature from the scientific databases for various aspects within the autonomous UAV path planning, such as type and configuration of UAVs, the complexity of their environments or workspaces, choices of path generating algorithms, nature of solutions and efficacy of the generated paths, necessitates an increased number of search keywords as a prerequisite. However, the addition of more and more keywords might as well curtail some conducive and worthwhile search results in the same pursuit. This article presents a Systematic Literature Review (SLR) for 20 useful parameters, organized into six distinct categories that researchers and industry practitioners usually consider. In this work, Web of Science (WOS) was selected to search the primary studies based on three keywords: “Autonomous” + “Path Planning” + “UAV” and following the exclusion and inclusion criteria defined within the SLR methodology, 90 primary studies were considered. Through literature synthesis, a unique perspective to see through the literature is established in terms of characteristic research sectors for UAVs. Moreover, open research challenges from recent studies and state-of-the-art contributions to address them were highlighted. It was also discovered that the autonomy of UAVs and the extent of their mission complexities go hand-in-hand, and the benchmark to define a fully autonomous UAV is an arbitral goal yet to be achieved. To further this quest, the study cites two key models to measure a drone’s autonomy and offers a novel complexity matrix to measure the extent of a drone’s autonomy. Additionally, since preliminary-level researchers often look for technical means to assess their ideas, the technologies used in academic research are also tabulated with references.

Optimal Elastic Wing for Flapping-Wing Robots Through Passive Morphing

Flapping wing robots show promise as platforms for safe and efficient flight in near-human operations, thanks to their ability to agile maneuver or perch at a low Reynolds number. The growing trend in the automatization of these robots has to go hand in hand with an increase in the payload capacity. This work provides a new passive morphing wing prototype to increase the payload of this type of UAV. The prototype is based on a biased elastic joint and the holistic research also includes the modelling, simulation and optimization scheme, thus allowing to adapt the prototype for any flapping wing robot. This model has been validated through flight experiments on the available platform, and it has also been demonstrated that the morphing prototype can increase the lift of the robot under study by up to 16% in real flight and 10% of estimated consumption reduction.

End-to-end Precision Agriculture UAV-Based Functionalities Tailored to Field Characteristics

This paper presents a novel, low-cost, user-friendly Precision Agriculture platform that attempts to alleviate the drawbacks of limited battery life by carefully designing missions tailored to each field’s specific, time-changing characteristics. The proposed system is capable of designing coverage missions for any type of UAV, integrating field characteristics into the resulting trajectory, such as irregular field shape and obstacles. The collected images are automatically processed to create detailed orthomosaics of the field and extract the corresponding vegetation indices. A novel mechanism is then introduced that automatically extracts possible problematic areas of the field and subsequently designs a follow-up UAV mission to acquire extra information on these regions. The toolchain is finished by using a deep learning module that was made just for finding weeds in the close-examination flight. For the development of such a deep-learning module, a new weed dataset from the UAV’s perspective, which is publicly available for download, was collected and annotated. All the above functionalities are enclosed in an open-source, end-to-end platform, named Cognitional Operations of micro Flying vehicles (CoFly). The effectiveness of the proposed system was tested and validated with extensive experimentation in agricultural fields with cotton in Larissa, Greece during two different crop sessions.