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In this article, motor failure control of a six-rotor electric vertical take-off and landing (eVTOL) urban air mobility aircraft is investigated using adaptive model predictive control (MPC) based on the linear parameter-varying (LPV) model developed using the nonlinear rigid-body aircraft model. For capturing the aircraft dynamics under motor failure conditions, a family of linearized models are obtained by trimming the nonlinear aircraft model at multiple equilibrium conditions and the LPV model is obtained by linking the linear models using the failed rotor speed, where the system transition from healthy to failure is modeled by a scheduling parameter calculated based on failed rotor speed caused by available motor peak power after failure. The proposed adaptive MPC is developed to optimize the system output performance, including the rigid-body aircraft velocity and altitude, by using quadratic programming optimization with reference compensation subject to a set of time-varying constraints representing the current available propeller acceleration calculated based on the motor power. Simulation study is conducted based on the developed LPV control design and original nonlinear rigid-body model, and the simulation results demonstrate that the designed adaptive MPC controller is able to recover and maintain the aircraft at desired stable condition after motor failure.

As a propulsion system for vertical take-off and landing (VTOL) aircraft, the gas-driven fan propulsion system has received some attention in recent years due to its simple mechanical structure and good performance. During the operation of the propulsion system, the core turbofan exhaust is directed to the tip turbine to drive the ducted fan to obtain thrust, and the louvered vector exhaust device is used to achieve lift/thrust switching. However, due to the linkage characteristics of the guide vanes of the exhaust device, the exhaust area will gradually change with the deflection of the guide vanes. This may cause uncertain effects on the system. Besides, considering the development cost of the propulsion system, it is necessary to clarify whether the core turbofan needs to be redesigned based on the characteristics of the system. Further, the transitional performance (VTOL to flight) of the propulsion system also needs to be studied. To this end, this study established an overall model of the gas-driven fan propulsion system combined with the characteristics of the core turbofan to analyze these problems. The results indicate that the louvered vector exhaust device can well match the gas-driven fan propulsion system. And when the propulsion system is composed, the gas-driven fan will not significantly affect the operation characteristics of the core turbofan. Besides, the preliminary analysis shows that the gas-driven fan propulsion system can meet the power requirements of the transition state of the fixed-wing VTOL aircraft. And the characteristics of the propulsion system may make the take-off thrust-weight ratio requirement of the fixed-wing VTOL aircraft be as low as 1.1.

The study considers the operation of an unmanned aerial vehicle in hovering mode over a flat landing platform. As a propulsion system, impellers are used, which are a system of a propeller rotating inside an air ring. The air ring is a body of revolution with an aerodynamic profile in cross section. The paper investigates the effect of unsteady interaction of vortex flows with the design of an aircraft by two alternative numerical methods, one of which is vortex-resolving. Numerical calculations are performed using the traditional turbulence modeling approach based on the averaged Navier–Stokes equations (RANS, Reynolds Averaged Navier–Stokes), where the turbulence is assumed to be isotropic, and the eddy-resolving Large Eddy Simulation method. The main feature of the latter is as follows: a turbulent flow is represented as the superposition of the motion of large-scale and small-scale turbulences. After discretizing the flow using a filtering operation, large-scale turbulence, which depends directly on the boundary conditions, is solved from the full Navier–Stokes equations. Small-scale turbulence has isotropic properties and is modeled similarly to semi-empirical RANS methods. The technique allows one to accurately calculate the vortex structure of any flow directly from the equations of motion using relatively low computing power, in contrast to the RANS models, which simulate the flow using a simplified mathematical model and can provide satisfactory accuracy only for a limited range of problems. The results indicate that eddy-resolving methods for modeling turbulence, in contrast to the methods based on averaged Navier–Stokes equations, make it possible to estimate the effect of aperiodic perturbations on the design of aircraft arising from the interaction of large eddies with each other and with the underlying surface. Such phenomena are accompanied by side impacts of a shock nature on the impeller rings, which can lead to loss of aircraft stability. Under conditions of a small propeller step, the use of an air ring results in a significant increase in the air flow passing through the rotor rotation loop, an increase in thrust due to the creation of flow circulation around the airfoil of the ring, and a decrease in the power on the propeller. Even though the effect of using an air ring disappears with a large incoming flow, this design is considered very promising for use on aircraft with vertical takeoff and landing. This mode of operation is the most energy-consuming and determines the greatest requirements for the lifting force of the power plant. The results of this work have demonstrated that numerical methods based on averaging the Navier–Stokes equations and the use of classical turbulence models of the k–ω or k–ε type, which are widely used in numerical modeling of propellers, in takeoff and landing modes fail to detect aperiodic unsteady phenomena associated with the interaction of large eddies, in contrast to eddy-resolving methods for modeling turbulence.

The interest in building hybrid Unmanned Aerial Vehicles (UAVs) is increasing intensively due to its capability to perform Vertical Take-Off and Landing (VTOL), in addition to forward flight. With this capability, the hybrid UAVs are highly on demand in various industries. In this paper, a fixed-wing VTOL UAV with a novel configuration of a dual rotor-embedded wing was designed and developed. The methodology used in the design process adopted the traditional sizing and aerodynamic estimation method with advanced computational simulations and estimation approaches. The design was determined based on a thorough analysis of weight contribution, aerodynamics, propulsion, and stability and control. The results show that the UAV’s preliminary design has successfully reached a total weight of 1.318 kg, achieved a high lift-to-drag ratio of approximately 4, and ensured stable flights with Level 1 flying qualities. A fixed-wing VTOL prototype was developed and fabricated based on the final design parameters using a low-cost hand lay-up process.

The subject of the article is the environmental research of the Pneumatic Para-chute Rescue System (PPRS) for an unmanned aerial vehicle, in which the parachute will be initiated from the reservoir by means of compressed carbon dioxide (CO2) stored in a special chamber. The research team has developed a program for researching the natural environment to simulate the conditions that may occur during the operation of an unmanned aerial vehicle and thus the Pneumatic Parachute Rescue System. UAV emergency scenarios were developed in which the developed rescue system should operate.

The article presents an analysis of the possibilities of supporting the Vertical Take off and Landing Unmanned Aerial Vehicle electric power systems by using photovoltaic cells. A typical commercial VTOL class drone with electric power was selected for analysis. Concepts of power supply supported by photovoltaic cells have been developed. Analysis of the potential change in performance through the use of such support are presented on the basis of the UAV simulation model and the model-based design. The simulation model takes into account not only the flight parameters of the drone, but also the drive system with the power supply system and the assumed variable lighting parameters. Such a multidisciplinary model was used to analyse the functional parameters. The analysis also includes hypothetical changes in the performance parameters of photovoltaic cells and their impact on the change in UAV performance as well as the impact of changes in the airframe geometry on the profitability of using such a solution.

The aim of this manuscript is to tackle the tracking problem for uncertain semi-Markov systems. More precisely, the mode-dependent event-triggering communication approach is introduced for networked controller design procedure, which can considerably increase the signal transmission efficiency. Based on the Lyapunov–Krasovski method, mode-dependent sufficient conditions are derived and the tracking errors could achieve the asymptotic mean-square stability, and mode-dependent controllers could be further calculated by convex optimization. A numerical simulation with application to vertical take-off and landing helicopter would be performed for verifying the availability and usefulness.

The paper focuses on a novel PID (proportional integral derivative) autotuner based on a single experi-mental sine test. The Kiss Circle (KC) autotuner design and validation are targeted on a vertical take-off and landing platform which exhibits a highly oscillatory non-linear motion with time delay. An additional autotuner fit for time delay processes such as the well-known Ziegler-Nichols method is used to determine a PID controller for the Vertical Take-Off and Landing (VTOL) process. The experimental results obtained with the two different experimental tuning methods under several operating conditions are compared, illustrating the superiority of the KC autotuner.

This publication addresses the proposed structural solution for a system, of which the conceptual essence involves a rescue parachute being ejected from an accumulator using compressed carbon dioxide. The suggested rescue system is intended for unmanned multicopter aircraft. The article presents a developed digital solid model and the results of its simulation tests. The paper also contains results of basic calculations of the pneumatic supply system energy balance and the power balance of the electric control system. It also presents the results of first in-flight tests with a simulated emergency situation and the use of a technology demonstrator in operating conditions. Simulational and experimental methods were chosen to solve the research problem.

The paper proposes a nonlinear optimal control approach for the model of the vertical take-off and landing (VTOL) aircraft. This aerial drone receives as control input a directed thrust, as well as forces acting on its wing tips. The latter forces are not perpendicular to the body axis of the drone but are tilted by a small angle. The dynamic model of the VTOL undergoes approximate linearization with the use of Taylor series expansion around a temporary operating point which is recomputed at each iteration of the control method. For the approximately linearized model, an H-infinity feedback controller is designed. The linearization procedure relies on the computation of the Jacobian matrices of the state-space model of the VTOL aircraft. The proposed control method stands for the solution of the optimal control problem for the nonlinear and multivariable dynamics of the aerial drone, under model uncertainties and external perturbations. For the computation of the controller’s feedback gains, an algebraic Riccati equation is solved at each time-step of the control method. The new nonlinear optimal control approach achieves fast and accurate tracking for all state variables of the VTOL aircraft, under moderate variations of the control inputs. The stability properties of the control scheme are proven through Lyapunov analysis.

In this study, the Deep Deterministic Policy Gradient (DDPG) algorithm, which consists of a combination of artificial neural networks and reinforcement learning, was applied to the Vertical Takeoff and Landing (VTOL) system model in order to control the pitch angle. This algorithm was selected because conventional control algorithms such as Proportional Integral Derivative (PID) controllers which cannot always generate a suitable control signal eliminating the disturbance and unwanted environment effects on the considered system. In order to control the system, training was carried out for a sinusoidal reference in the mathematical model of the VTOL system in the Simulink environment, through the DDPG algorithm with continuous action space from deep reinforcement learning methods that can produce control action values that take the structure that can maximize the reward according to a determined reward function for the purpose of control and the generalization ability of artificial neural networks. For sinusoidal reference and a constant reference, tracking error performances obtained for the pitch angle, which is the output for the specified VTOL system, were compared with the conventional PID controller performance in terms of mean square error, integral square error, integral absolute error, percentage overshoot and settling time. The obtained results are presented via the simulations studies., Bu çalışmada, yapay sinir ağları ve pekiştirmeli öğrenmenin birleşiminden oluşan Deep Deterministic Policy Gradient (DDPG) derin pekiştirme öğrenme algoritması Dikey Kalkış ve İniş (VTOL) sistemi modeline yunuslama (pitch) açısını kontrol edebilme amacıyla uygulanmıştır. Bu algoritma, Oransal İntegral Türevsel (PID) kontrolör gibi geleneksel kontrol algoritmaları için en uygun kontrolör katsayıları bulunsa dahi kontrol edilecek sistem üzerindeki bozucu etki ve istenmeyen ortam etkilerini elimine edebilecek kontrol sinyali üretememelerinden dolayı seçilmiştir. Belirtilen bu problemi çözebilmek için kontrol amacına yönelik belirlenen bir ödül fonksiyonuna göre ödülü maksimize edebilecek yapısı ve yapay sinir ağlarının genelleştirme yeteneğini arkasına alan kontrol aksiyon değerleri üretebilen derin pekiştirmeli öğrenme yöntemlerinden sürekli eylem uzayına sahip DDPG algoritmasının, Simulink ortamında VTOL sisteminin matematiksel modelinde sinüzoidal bir referans için eğitimi gerçekleştirilmiştir. Belirtilen VTOL sistemi için çıkış olan yunuslama açısının, DDPG algoritması için sinusoidal ve sabit referans için elde edilen izleme başarımları, geleneksel PID kontrolör algoritmasının izleme başarımları ile ortalama kare hatası, integral kare hatası, integral mutlak hatası, yüzde aşım ve oturma zamanı cinsinden karşılaştırılmıştır ve edinilen sonuçlar simülasyon çalışmaları ile sunulmuştur.

This study presents a concept hybrid UAV (Unmanned Aerial Vehicle) design that is capable of a conventional fixed-wing as well as VTOL (Vertical Takeoff and Landing) features. The main aim of the study is to conduct a stability analysis for this concept VTOL UAV design. Only longitudinal stability is preferred at this stage for the operation when UAV switches from VTOL to fixed-wing configuration. The stability of the concept design was analyzed by developing a special MATLAB program. The results show that the concept design is statically and dynamically stable especially during the transformation phase from VTOL to fixed-wing configuration. This design concept can be used for several military operations in rugged areas such as surveillance, search and rescue, border security, and target missions.

Contemporary trends are leading towards the electrification of aircraft for urban mobility applications. Accordingly, there is a high demand for advancements in light-weight, high voltage technologies to realize these new aircraft types. Driven by recent developments in the automotive industry, hybrid Pyrofuse protection devices have emerged as one such new candidate technology. Pyrofuses offer rapid clearance of fault currents, reduced cost and weight when compared to conventional mechanical breakers. In addition, Pyrofuses have the ability to tune the time-current curve to fit the application's fault response characteristics. However, Pyrofuses are non-resettable devices whose exclusive use for electrical protection could present potential operational hazards and certification challenges in aerospace applications. Model-based analysis will be critical in supporting this evaluation. Accordingly, this paper offers the first complete design methodology to transiently model Pyrofuse operation in MATLAB/Simulink, drawing characteristics from commercially available datasheets. This model is then utilized to undertake an initial protection coordination feasibility study for a candidate eVTOL electrical system architecture, exploring the associated device and system level operational capabilities and limitations. In particular, the results show that the Pyrofuse can offer a good degree of nuisance-tripping resilience against transient events whilst providing quick clearance of short circuit faults.

A Vertical Take-Off and Landing (VTOL) system is highly unstable and hence a robust controller is needed to stabilize it in finite time. This work presents the design of a Fractional Order Proportional-Integral-Derivative (FOPID) controller to stabilize the VTOL system. The applied FOPID controller has been tuned, to achieve the desired performance and robustness, by Fractional Order Particle Swarm Optimization (FOPSO), which is a modified form of the original PSO obtained by generalizing the order of the velocity derivative to a real number \(0 \le \alpha \le 1\). This helps in smoother transitions, better exploration and longer memory of the particles. The results obtained using the FOPID controller has been compared with the conventional PID controller. It has been found that the FOPID controller exhibits superior performance and robustness.

Electric vertical takeoff and landing (eVTOL) aircraft of the lift+cruise configuration are significantly impacted by the drag of the lift propellers even though they are only briefly used for takeoff and landing. This work aims to quantify the drag penalty of these high lift propellers, its impact on the performance of a lift+cruise eVTOL aircraft, and potential benefits from retracting the propellers during cruise. An eVTOL model is tested in the wind tunnel with propellers extended and retracted. Results show that retracting the propellers reduces parasitic drag by 38%. This measured drag reduction is used to estimate the performance of a passenger eVTOL and a surveillance drone employing a propeller retraction system. A passenger carrying eVTOL lift+cruise aircraft with a propeller retraction system could cruise 21% faster, at the same mission range, or increase range by 13% at the same flight speed. When endurance is the main mission objective, the benefits are smaller, in the order of 7%, and the potential gains are more sensitive to the weight of the retraction system.

Going from more conventional aircrafts to eVTOL (electric Vertical Take Off and Landing), the electrification trends are forcing aircraft manufacturers to work on compact and safe electrical machine solutions. This paper utilizes a 2D approach for an adjustable air gap permanent magnet electrical machine to choose the best motor attributes. Firstly, the 2D model is calibrated using existing experimental measures, then, it is employed to find multiple solutions that accomplish the mechanical flux-weakening. It is demonstrated that the choice of the best combination of the motor tapering and axial displacement can be influenced by the mechanical system configuration and control accuracy.

Vertical take-off and landing unmanned aerial vehicles (VTOL UAV) are widely used in various fields because of their stable flight, easy operation, and low requirements for take-off and landing environments. To further expand the UAV&rsquo, s take-off and landing environment to include a non-structural complex environment, this study developed a landing gear robot for VTOL vehicles. This article mainly introduces the adaptive landing control of the landing gear robot in an unstructured environment. Based on the depth camera (TOF camera), IMU, and optical flow sensor, the control system achieves multi-sensor data fusion and uses a robotic kinematical model to achieve adaptive landing. Finally, this study verifies the feasibility and effectiveness of adaptive landing through experiments.

Landing platforms’ automation is aimed at servicing vertical take-off and landing UAVs between flights and maintaining their airworthiness. Over the last few years, different designs for the landing platforms have been proposed. This shows a strong development and establishment of automatic landing platforms with UAV positioning devices on the landing site. Positioning and safe fixation of the UAV are some of the main features of the landing platform, especially if it is mounted on a movable vehicle. This article focuses exclusively on the landing platform and its elements that provide the positioning of the UAV by affecting it during and after the landing. Both active devices and mechanisms and passive elements used for positioning are considered. This article, based on the review of recent patents and publications, gives the classification of positioning approaches used in landing stations with the analysis of the required landing precision, as well as the pros and cons of each type of approach.

This paper presents the modeling, simulation, and control of a small-scale electric powered quadrotor tail-sitter vertical take-off and landing unmanned aerial vehicle. In the modeling part, a full attitude wind tunnel test is performed on the full-scale unmanned aerial vehicle to capture its aerodynamics over the flight envelope. To accurately capture the degradation of motor thrust and torque at the presence of the forward speed, a wind tunnel test on the motor and propeller is also carried out. The extensive wind tunnel tests, when combined with the unmanned aerial vehicle kinematics model, dynamics model and other practical constraints such as motor saturation and delay, lead to a complete flight simulator that can accurately reveal the actual aircraft dynamics as verified by actual flight experiments. Based on the developed model, a unified attitude controller and a stable transition controller are designed and verified. Both simulation and experiments show that the developed attitude controller can stabilize the unmanned aerial vehicle attitude over the entire flight envelope and the transition controller can successfully transit the unmanned aerial vehicle from vertical flight to level flight with negligible altitude dropping, a common and fundamental challenge for tail-sitter vertical take-off and landing aircrafts. Finally, when supplied with the designed controller, the tail-sitter unmanned aerial vehicle can achieve a wide flight speed envelope ranging from stationary hovering to fast level flight. This feature dramatically distinguishes our aircraft from conventional fixed-wing airplanes.

The subject of this publication is a mathematical model of a pneumatic supply system for an emergency parachute system. This system is intended for a vertical take-off and landing UAV. An overview of emergency parachute landing system designs is presented in the introduction. Based on a schematic diagram and a 3D computer model, the construction and operation principles of an emergency parachute system, currently being developed at AFIT, was presented. A mathematical model, which enables the determination of the energy of gas (compressed CO2) stored in the accumulator tank was described. The conducted tests, which involved weighing the accumulator after filling with liquefied CO2 from a special cartridge and equivalent mass ejections were discussed. These tests involved recording the track of the equivalent mass movement and time necessary to determine velocity. The results of calculations regarding the equivalent mass energy imitating an emergency parachute, CO2 volume and mass in the accumulator in liquefied and gaseous state were presented. Based on the conducted calculations and the obtained characteristics, the developed mathematical model was assessed, and the final conclusions formulated.

A structural-parametric analysis of the effect of infrastructure constraints in the basing of vertical take-off and landing aircrafts (VTLA) on the choice of alternative variants of power units (PU) was carried out. An algorithm for obtaining a combined power unit scheme is considered as a solution to the contradiction between the unified and composite power unit schemes of vertical take-off and landing aircrafts. The method of arranging the vertical take-off and landing aircrafts from the virtual center of mass is given, which allows us to obtain the layout diagram of the aircraft from the conditions of infrastructural restrictions on the deck of the airborne cruiser. A method for the synthesis of new aircraft circuit design is proposed. A graphic representation of the concept of a light vertical take-off and landing aircraft with a deck base, providing the vertical position of the aircraft during take-off and horizontal landing, is given.

This publication continues a series of review papers devoted to the urgent problems of designing unmanned aircrafts of the next generation, which are expected to appear in the period from 2025 to 2035. The paper considers simple and effective numerical methods based on the ideas of a vortex lift surface that allow for performing a full parametric analysis of aircrafts with very complex aerodynamic shape of the wing. Calculation examples are given for triangular wing of small and moderate aspect ratio with an acute and rounded leading edge, as well as a wing of complex shape. We consider design methods for deformed aerodynamic surfaces with optimal properties and a method for wing mechanization calculating. The formation of vortices on sharp front edges, the destruction of vortices over the wing surface and diffusion mechanism of vortices are studied. The calculation method for small aspect ratio wings is described. The results obtained are compared with the results of the experiment and numerical verification.

—A Hybrid Unmanned Aerial Vehicle (UAV) has both advantages of multirotor and fixed-wing UAV. This unique design leads to a more complicated airframe and control design compared to those of a conventional drone. Integrating two platform of UAV (mutirotor and fixed-wing) also requires carefully consideration to safely operate this hybrid UAV. This paper discussed the flight scenario that includes flight modes and parameters to be determined before flight. This leads to the development of the flight procedure as an important prerequisite for a successful flight.

Tilting ducted fans attached to the wing tips of vertical take-off and landing unmanned aerial vehicles define new applications for these types of aerial vehicles. This new configuration gives vertical take-off and landing unmanned aerial vehicles the ability to hover like helicopters and fly forward like airplanes, which results in using any arbitrary location for take-off and landing combined with increasing range and speed. Furthermore, generating additional lift using asymmetrical shape for the external body of the ducted fans can lead to reducing the wing area and related overall drag, which results in saving more energy. This research provides experimental results from wind tunnel tests in addition to computational fluid dynamics simulations to investigate the advantages of using an asymmetrical tilting ducted fan instead of a symmetrical one. “actuator disk model” combined with the assumption of “constant delivered power” to the propeller were used successfully to calculate the induced velocity to the rotor plane of the ducted fan in the computational fluid dynamics simulations. The effects of the stall and flow separation on the aerodynamic coefficients were also studied and compared for the symmetrical and asymmetrical ducted fans. Both computational fluid dynamics and experimental results showed noticeable improvement in the lift coefficient using an asymmetrical shape for the external body of the tilting ducted fans.

Vertical take-off and landing (VTOL) is a futuristic mode of transport that can potentially revolutionize the way we commute. However, despite the technical leads offered by VTOL, the feasibility of this state-of-the-art urban commute needs to be established from various aspects. This study assesses the temporal and economic benefits offered by VTOL technology over the conventional road taxi service. The mode ‘taxi’ is chosen as it is thought to compete, as a chief mode of urban transport, with the VTOL transport in future. The comparison is based on two decisive factors: the peak hour travel-time and fare by taxi and VTOL on 44 routes in five metropolitan cities: New York, Los Angeles, London, Munich and Shanghai. Analysis of Variance (ANOVA) is performed on the data set and conclusion is drawn on the statistical significance of the difference in the response variables (time and fare) by mode choice (VTOL versus Taxi). VTOL is found to offer significant advantages over the surface transport (taxi) in terms of time and fare. The findings of this study are expected to assist in determining the practicality of VTOL systems. Moreover, the methodology used here is reproducible and provides a framework for testing the practicality of other futuristic transport modes (such as hyperloop).

This research investigated the combination of a fuel cell and ultracapacitors to create a hybrid powertrain for a vertical take-off unmanned aerial system (UAS). This replaced the more common battery-only powertrain or the hybrid fuel cell-battery powertrain. A secondary power source, such as a battery or ultracapacitors, is required to assist a fuel cell with immediate load requests because fuel cells are unable to supply instantaneous power. The fuel cell-ultracapacitor was tested using a power profile that was experimentally determined using a battery-powered vertical take-off UAS during take-off, hover, and landing. This tabletop experiment is meant to lead to a more refined solution that can be easily scaled to fit into a smaller future vertical take-off UAS. Two separate ultracapacitor banks were made to be put in parallel with the fuel cell. The first was a series of 14, 650 Farad ultracapacitors and the second was a series of 14, 350 Farad ultracapacitors. Both fuel cell-ultracapacitor powertrains were able to meet the power requirements while also supplying power to the fuel cell itself, without an external power supply. Future work opportunities include scaling for implementation into a UAS platform and coding the power management software to optimally manage the proposed hybrid powertrain.

The use of Vertical Take-Off and Landing (VTOL) Unmanned Aerial Vehicles (UAV) has shown significant benefits in various applications. Integrating UAV's with a Fused Deposition Modelling (FDM) fabrication method, allows for modular and on-demand configurations according to required specifications. A new prototype named the Triodactyl was designed and fabricated using the FDM method. An experimental setup validated the prototypes structural and aerodynamic capabilities. It was noted that modifications to certain FDM parameters provided an increased structural integrity.

Flight endurance is still a bottleneck for many types of unmanned air vehicle (UAV) applications. While battery technology improves over the years, for flights that last an entire day, batteries are still insufficient. Hydrogen-powered fuel cells offer an interesting alternative but pose stringent requirements on the platform. The required cruise power must be sufficiently low and flying with a pressurized tank poses new safety and shape constraints. This paper proposes a hybrid transitioning UAV that is optimized towards carrying a hydrogen tank and fuel cell. Hover is achieved using 12 redundant propellers connected to a dual Controller Area Network (CAN) bus and dual power supply. Forward flight is achieved using a tandem wing configuration. The tandem wing not only minimizes the required wingspan to minimize perturbations from gusts during hover, but it also handles the very large pitch inertia of the inline pressure tank and fuel cell very well. During forward flight, 8 of the 12 propellers are folded while the tip propellers counteract the tip vortexes. The propulsion is tested on a force balance and the selected fuel cell is tested in the lab. Finally, a prototype is built and tested in-flight using battery power. Stable hover, good transitioning properties, and stable forward flight are demonstrated.

An unmanned aerial vehicle (UAV) that is able to take-off and land on a medium sized ship, have greater endurance and range as compared to the previous iteration, and the ability to achieve all three flight modes - vertical, transition and horizontal flight modes is to be designed, built and tested. In this paper a comprehensive review is given on various VTOL planform configuration and a tilt-rotor configuration is selected for Minerva 2.0 for its high stability and increased efficiency. This paper covers the selection analysis of different vertical take-off and landing (VTOL) airframe as well as mechanical and electronic hardware design with the intention of increasing flight efficiency for surveillance purposes on wide sea area. This paper presents Minerva 2.0, a novel aerial platform with VTOL capabilities. Numerical and analytical analysis results are discussed. The previous iteration, Minerva 1.0 was built and tested as a QuadPlane configuration and an increased efficiency of 25 to 58.7% is achieved in this paper.

Ground charging stations for electrical unmanned aerial vehicles (aerial robots) based on open contact pads are considered in the paper. All known technical solutions concerning charging stations of such a type are systematized. A few classification criterions are proposed. The most interesting technical solutions are described. Two original authors' development works are presented. These are the charging station based on arrays of the so-called intelligent contact pads and the charging station based on flat parallel electrodes. Each of these projects has own advantages and disadvantages, but both solutions provide arrangement of charging process even in conditions of inaccurate aerial robot landing, and all the more so, provide charging for a group of aerial robots simultaneously.

This paper introduces the modeling and control of a Planar Vertical Take Off and Landing (PVTOL) aircraft with tilting rotors. The mathematical model is obtained step by step using the Newton-Euler methodology. Its nonlinear dynamics of this aircraft are analyzed and controlled using a nonlinear and a linear algorithm. The controllers were validated in simulation and main results are depicted in some graphs showing differences between both. Good results are observed when applying the nonlinear controller based on nested saturation.

Presented in this paper are the design and experiments for a transformable Vertical Take Off and Landing (VTOL) UAV. This work demonstrates shape-shifting transformation, building upon the conceptual designs put forth in [1] and [2], along with hardware prototyping and component testing from [3]. A deterministic model is presented to characterize the flight of the MIST-UAV in simulation. Experimental results from the platform demonstrate for the first time successful in-air transformation from multi-rotor, tail-sitter, and fixed-wing operation. Experiments also validated transformation repeatability, successfully testing multiple sequential transformations.

Transmission towers in remote areas are located in a complex terrain, usually far away from roads, making it difficult for inspectors to approach to deploy auxiliary inspection equipment. Therefore, inspection tasks for such transmission towers have become a time-consuming and laborious hard bone. In response to this problem, this paper proposes a new, safe and efficient form of inspection operations based on a vertical take-off and landing unmanned aerial vehicle (VTOL) which is equipped with a strap-down lateral imaging module to assist in the inspection of electrical towers. Based on the known longitude and latitude information of transmission towers, the inspection route is pre-planned offline. When the VTOL reaches a certain transmission tower, it can be controlled to hover around the center point of the transmission tower at a fixed height. The strap-down lateral imaging module could obtain image information of the transmission tower to monitor the status of the transmission tower. In addition, line-of-sight angles of the center point of the transmission tower in the image can be extracted to help to adjust the height and radius of the VTOL hovering around the transmission tower, so as to achieve the most effective inspection of the transmission tower with a low-cost strap-down industrial camera. The algorithms of the scheme in this paper have been implemented in reliable hardware modules. The scheme has the capability of an actual flight inspection.

Unmanned aerial vehicle is the most widely used aircraft technology due to its eminent applications in various fields like in military for surveillance, patrolling and rescue operations, agriculture and civil uses like food delivery, Aerial photography etc. There are two main categories of UAVs; Fixed-wing UAVs and multi-rotor UAVs. There are some issues which arise with conventional aerial vehicles like the absence of enough runway in rural areas and dense forests. Vertical take-off and landing (VTOL) UAVs have the advantages of both fixed-wing and fixed rotor type aircraft. These types of aircraft are more suitable for such applications where lack of runway and dense forests are major issues. This review article mainly focuses on the work done in the domain of design and analysis of vertical take-off and landing (VTOL)

In this current era of technology VTOL UAVS is an emerging technology that is becoming popular for its variety of applications like Agriculture, Civil, and military for Surveillance, rescue missions, and patrolling. These types of aircraft came into existence as the solution to many issues like lack of runways in rural areas and dense forests. VTOL UAV is a hybrid of a helicopter and fixed-wing aircraft because it has the functionality of both types of aircraft. These aircraft possess high hovering efficiencies like a helicopter and a better cruising speed like a fixed-wing aircraft with an enhanced payload capacity. Many interesting applications of these aircraft is attracting researchers to work in this field. In this paper, a CFD approach has been adopted for the analysis of TURAC tilt-rotor type VTOL UAV with the help of XFLR software.

Recently, the market for drones is growing rapidly. Commercial UAVs (Unmanned Aerial Vehicles, or drones) are increasingly being used for various purposes, such as geographic survey, rescue missions, inspection of industrial facilities, traffic monitoring and delivery of cargos and goods. In particular, the drones have great potential for life-saving operations. A missing person, for example, can be rapidly and effectively searched using a drone in comparison with the conventional search operations. However, there is no commercially available rescue UAV until now. The motivation for this study is to design an unmanned aerial vehicle capable of vertical takeoff and landing, while containing a high power propellant apparatus in order to lift a heavy cargo that contains rescue materials (such as water, food, and medicine). We used the EDF (Electric Ducted Fan) technology as opposed to the conventional motor and prop combination. The EDF can produce the power about three times higher than the motor-prop combination. This became suitable for transportation of rescue goods, and can be widely used in rescue operations in natural environments. Based on these results, the UAV for rescue material transport capable of heavy vertical takeoff and landing is developed, including airframe, flight control computer and GCS (ground control station).

[abstFig src='/00280003/06.jpg' width=""155"" text='Prototype of proposed aircraft' ] Trial production has begun on tricopter-based new-concept vertical take-off and landing aircraft (VTOL). The VTOL features three fixed-angle motors on a reversed-T shape body and a fixed wing with an elevon and a rudder. The proposed craft uses fewer components than quadcopter-based VTOL craft. Continuous transition from rotorcraft to fixed-wing craft is completed with the craft’s 90° tilt.

Quadrotor helicopters or simply called as Quadrotors represent a useful class of flying robots and are an emerging popular platform for unmanned aerial vehicle (UAV) research and have applications of their own. Due to their simplicity of construction, easy maintenance, their ability to hover effortlessly, strong abilities of VTOL, vertical take off and landing (VTOL) capabilities, high manoeuvrability and controllability (especially in indoor areas). In this paper, we present the development of an unmanned UAV, called Quadrotor, which has the abilities to perform acrobatic movements like flips, rolls, barrels etc. It is also able to capture real time videos using a RF wireless camera. These videos are converted to snapshots which are then processed using MATLAB-Image Processing Toolbox to count the number of persons in that specific captured image.

This paper formulates and solves a new problem of global practical inverse optimal control of underactuated vertical take-off and landing (VTOL) aircraft. The control design is based on a recent development of inverse optimal control design for nonlinear systems, and ensures global practical K ∞ -exponential stability of stabilization errors. More importantly, it also minimizes a cost function that penalizes both stabilization errors and control inputs without having to solve a Hamilton–Jacobi–Bellman or Hamilton–Jacobi–Isaacs equation.

The recent advances in battery energy density and electric propulsion systems for automotive applications are enabling the development of the electric vertical take-off and landing (VTOL) aircraft. The electric VTOL is a new means of transport that can fly like an aircraft and take off and land vertically like a helicopter, sometimes called personal aerial vehicle. This paper compares it to the existing vehicles that may compete with it and addresses the estimation of its performances in hover, cruise flight, and the transition phase. The main parameters affecting performances are then discussed. Considerable space is dedicated to the battery mass to total mass ratio.