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This paper presents a novel incremental sliding mode control scheme to address the attitude-tracking issue in both the helicopter and airplane modes of an electric vertical takeoff and landing vehicle, guaranteeing the stabilization of the attitude-tracking error within a predefined time. Firstly, an incremental model of the vehicle's attitude control system with external disturbances is established. The high-order terms of the incremental model and instantaneous perturbations are retained as lumped terms rather than directly discarding them to ensure the accuracy of the incremental model. Then, a novel nonsingular sliding surface is developed. Once the ideal sliding motion is established, the states on the sliding surface will converge to the equilibrium point within a predefined time. Furthermore, a predefined-time incremental sliding mode controller is developed by using sliding mode control and incremental control techniques. It effectively reduces the reliance on the model information and attenuates the effects of external disturbances. The predefined-time stability of the entire controlled system is rigorously proven using Lyapunov theory. Finally, numerical simulation examples verify the effectiveness of the proposed control scheme. [ABSTRACT FROM AUTHOR]

The article discusses the importance of research in the field of flight dynamics, control, and simulation for advancing aeronautical sciences. It emphasizes the need for a deep understanding of flight dynamics to enhance aircraft performance, safety, and efficiency. The integration of advanced control strategies and the use of simulation play a crucial role in optimizing aircraft behavior and reducing costs. The article also provides an overview of 14 papers published in a special issue of the Aerospace journal, covering various topics such as hybrid electric propulsion, aerodynamic parameter identification, and autonomous flare control. The research presented in the papers contributes to the development of new technologies and innovations in aviation. [Extracted from the article]

Electrification of aircraft is a very challenging task as the demand for energy and power is high. While the storage and generation of electrical energy are widely studied due to the limited specific energy and specific power of batteries and fuel cells, electric machines (power electronics and motors) which have years of experience in many industrial fields must be improved when applied to aviation: they generally have a high efficiency but the increase in power levels determines significant thermal loads which, unlike internal combustion engines (ICE), cannot be rejected with the exhaust. There is therefore a need for thermal management systems (TMSs) with the main objective of maintaining operating temperatures below the maximum level required by electric machines. Turboprop aircraft, such as the ATR 72 or the Dash 8-Q400, are commonly used for regional transport and are equipped with two gas turbine engines whose combined power is in the order of 4 MW. Electric and hybrid propulsion systems for these aircraft are being studied by several leading commercial aviation industries and start-ups, and the 1MW motor size seems to be the main option as it could be used in different aircraft configurations, particularly those that exploit distributed electric propulsion. With reference to the topics mentioned above, the present work presents the design of a TMS for a high-power motor/generator whose electrical architecture is known. Once integrated with the electrical part, the TMS must allow a weight/power ratio of 14 kW/kg (or 20 kW/kg at peak power) while maintaining the temperature below the limit temperature with reasonable safety margins. Submerged jet oil is the cooling technique here applied with a focus on diathermic oil. Parameters affecting cooling, like rotor speed and filling factor, are analysed with advanced CFD. [ABSTRACT FROM AUTHOR]

As global warming intensifies, the world is increasingly concerned about carbon emissions. As an important industry that affects carbon emissions, the air transportation industry takes on the important task of energy saving and emission reduction. For this reason, major airlines have designed or will design different kinds of new-energy aircraft; however, each aircraft has a different scope of application according to its energy source. Biofuels have an obvious carbon emission reduction effect in the whole life cycle, which can offset the drawback of the high pollutant emission of traditional fossil fuels in the preparation and combustion stages. At the same time, a battery has zero emissions in the operating condition, while the low energy density also makes it more applicable to short-range navigation in small aircraft. In this paper, the development direction of a biofuel–electric hybrid aircraft is proposed based on the current development of green aviation, combining the characteristics of biofuel and electric aircraft. [ABSTRACT FROM AUTHOR]

As the population of the world's major cities increases, urban ground transportation capability reaches its limits. Consequently, electric vertical takeoff and landing aircraft have been developed to address this issue. Modern vertical takeoff and landing designs vary in configurations, each possessing distinct aerodynamic properties. In this work, we focus on the interaction between rotors and fixed wings in a parallel layout, using a prototype with an unconventional configuration as an example. The interaction between the slipstream of rotors and the wake of fixed wings is analyzed using the vortex particle method. Actuator surface model is used to deal with the boundary problem between the wing and the rotors. The applicability of the simulation method adopted in this paper is verified through experimental tests on the thrust and torque of the rotors. The results indicate that under the condition of forward flight at zero angle of attack, the existence of rotor slipstream induces a significant increase by three to four times the local lift on the wing. Correspondingly, under vertical takeoff and hovering conditions, the existence of the rotor slipstream causes the local effective velocity and circulation of the wing to increase. On the other hand, at zero angle of attack and a forward flight, the lift coefficient of the rear rotors increases slightly due to the presence of the wing wake. The lift distribution of the rear rotors along the radial direction also changes greatly. [ABSTRACT FROM AUTHOR]

The passive safety in aircraft concerns all measures able to protect the passengers and crew in the event of an accident or emergency. In this context, an important role is played by the design adopted for components inside the passengers' cabin, such as the seats and the interior lining. An effective approach in design of passive safety system is provided by anthropomorphic test devices. In this work, a new design of the interior lining of the fuselage wall has been introduced and its crashworthiness features have been studied through a side impact of an unbelted window‐side passenger. The new proposed interior lining is made with a hybrid sandwich‐based design with a polypropylene honeycomb core able to ensure passive safety for passengers and thermal and acoustic insulation. [ABSTRACT FROM AUTHOR]

This paper proposes a comprehensive power system designed for the use of a more electric aircraft power distribution system. Instead of traditional Nicad battery solutions as the energy source of the aircraft power system, lithium battery structures, which are a recent and promising solution in the field of aviation power systems, are modeled and analyzed. In this study, a WPWM-based, single-phase, multi-level pure sine wave static aircraft-inverter system is designed and integrated to improve the performance of conventional aircraft power systems. In the designed power system, a boost converter structure is proposed that boosts 28 VDC-to-270 VDC voltage coming from the lithium–ion battery pack and can reach a steady state in 0.032 s. The performance of the modeled WPWM-based aircraft-inverter system, compared to SPWM Bipolar and Unipolar switching techniques commonly used in single-phase inverter designs, reveals a THD reduction of approximately 27% with WPWM, resulting in a THD value below 2% for both load current and load voltage. As a result of the study, a power system that will enable the aircraft avionics, ventilation, and navigation systems to perform better than conventional power systems and comply with aircraft electric-power characteristic standards has been designed and detailed. [ABSTRACT FROM AUTHOR]

The article concerns the problem of capacitor diagnosis in a hybrid aircraft. Capacitors are one of the most commonly damaged components of electrical vehicle drive systems. The result of these failures is an increase in voltage ripple. Most known analytical methods are based on frequency spectrum analysis, which is time-consuming and computationally complex. The use of deep neural networks (DNNs) allows for the direct use of the measurement signal, which reduces the operating time of the overall diagnostic system. However, the problem with these networks is the long training process. Therefore, this article uses transfer learning (TL), which allows for the secondary use of previously learnt DNNs. To collect data to learn the network, a test bench with the ability to simulate a capacitor failure was constructed, and a model based on it was made in the MATLAB/Simulink environment. A convolutional neural network (CNN) structure was developed and trained by the TL method to estimate the capacitance of the capacitor based on signals from the Simulink-designed model. The proposed fault diagnostic method is characterised by a nearly 100% efficiency in determining capacitance, with an operating time of about 10 ms, regardless of load and supply voltage. [ABSTRACT FROM AUTHOR]

The positioning of civil aviation aircraft relative to a geographic reference point on Earth in a Cartesian frame is significant to detect the deviations from the desired path, especially for high-altitude airports or special airports based on performance-based navigation (PBN). To obtain these critical deviations during aircraft approach and landing, it is fundamental to estimate the continuous flight variables and discrete flight modes simultaneously with enough accuracy. With the coordinate conversion between the North, East, and Down (NED) frame and the geographic coordinate system based on World Geodetic System 1984 (WGS-84) considered, this study proposed a non-linear stochastic hybrid estimation algorithm with adaptive square-root unscented particle filtering (ASR-UPF) to estimate the true path. The probabilities of mode transition, represented by the normal cumulative density function of continuous states, determine whether to proceed with mode transitions. In addition, the adaptive update characterized by tracking variable noise and the importance sampling distributions based on the results of square-root unscented Kalman filtering (SR-UKF), as a comparative study of continuous system filtering, were used. The experiments illustrated the ASR-UPF is able to reduce the state estimation error more effectively, and more promptly track the error caused by incorrect mode estimation with adaptability compared to the SR-UKF. A further test with real flight data indicates that the proposed method gives the refined estimation of position and azimuth in NED frame. [ABSTRACT FROM AUTHOR]

For the aviation sector, it is extremely important to devise revolutionary solutions in the field of technology to restrain the potential impact of civil aviation on the environment to the level of the established strategic goals of ACARE (FlightPath2050). The introduction of innovative technologies (improvement of the combustion chamber, the introduction of electric hybrid power plants on airplanes, and the use of alternative aviation fuel) will ensure the sustainable growth of air transportation. To assess the effectiveness of advanced technologies, it is extremely important to have a model for calculating global/local emissions that takes into account the parameters of the flight path of conventional and hybrid aircraft, operational characteristics of the aircraft engine and hybrid powerplant, and the features of sustainable fuel. The improved module for calculating emission indices by combining the module for calculating the parameters of the flight path and the results of calculating the thermogas-dynamic calculation of the aircraft engine makes it possible to detect the influence of fuel consumption (engine thrust) on the values of the emission indices. This feature is representative for evaluating the efficiency of hybrid powerplants because the electrification of the aircraft fleet is primarily aimed at reducing fuel consumption. The analysis of simulation results reveals that the fuel consumption and EINOx are significantly reduced (for the climb stage – 25 %; for the descent stage – 30 %) for the hybrid AN26 compared to the conventional AN26. The specified operational measure, in the part of the low-pitch descend, significantly reduces EICO for the hybrid AN26 by an average of 50 % compared to the descend stage for the conventional trajectory. The results of calculations for the entire flight path demonstrate that the use of a hybrid power plant for An26 contributes to an average reduction of fuel consumption by 10 %, NOx emissions by 25 %, water vapor emissions by 10 %, and CO2 by 10 %. [ABSTRACT FROM AUTHOR]

We experimentally demonstrate the tuning of accidental bound states in the continuum (A-BICs) in silicon nanodisk arrays. The A-BIC emerges of the destructive interference of multipoles, which are the dominating out-of-plane electric dipole and in-plane magnetic dipole, and weak electric quadrupole and magnetic quadrupole. We further show that the spectral and angular position of the A-BIC can be conveniently tuned by varying the nanodisk size or the lattice period. Remarkably, the angular position can be tuned even to 0°, suggesting an interesting transition of the A-BIC from an off-Γ-BIC to an at-Γ-BIC. Our work provides a new strategy for light trapping with high quality factors, and the obtained tunable A-BICs can find potential applications in low-threshold lasing, enhanced nonlinear optics, and optical sensing. [ABSTRACT FROM AUTHOR]

This research aims to identify and evaluate the key challenges and obstacles hindering the adoption of sustainable energy in the aviation industry. The outcomes and insights derived from this research will be synthesized to provide a comprehensive overview of the opportunities and suggestions for the adoption of sustainable energy in the aviation industry. The objective of this study is to help the aviation industry's shift toward more sustainable energy sources in order to reduce its environmental footprint and mitigate the effects of climate change. [ABSTRACT FROM AUTHOR]

The aviation industry has proposed multiple solutions to reduce fuel consumption, air pollution, and noise at airports, one of which involves deploying electric trucks for aircraft towing between the stand and the runway. However, the introduction of tow trucks results in increased surface traffic, posing challenges from the perspective of air traffic controllers (ATCOs). Various solutions involving automated planning and execution have been proposed, but many are constrained by their inability to manage multiple active runways simultaneously, and their failure to account for the tow truck battery state of charge during assignments. This paper presents a novel system for taxi operations that employs autonomous tow trucks to enhance ground operations and address deficiencies in existing approaches. The system focuses on identifying conflict-free solutions that minimise taxi-related delays and route length while maximising the efficient use of the tow trucks. The algorithm operates at a strategic level and uses a centralised approach. It has the capacity to cater for multiple active runways and considers factors such as the tow truck battery state of charge and availability of charging stations. Furthermore, the proposed algorithm is capable of scheduling and routing tow trucks for aircraft taxiing without generating traffic conflicts. [ABSTRACT FROM AUTHOR]

Electrically powered airplanes can cope with global warming by reducing the use of fossil fuels and reduce airplane costs in the long run through the efficient use of energy. For this reason, advanced aviation countries such as the United States and several countries in the European Union are leading the development of innovative technologies to realize a fully electric airplane in the future. Currently, research and development efforts are underway domestically to convert existing two-seater airplanes into electric-powered airplanes. In this study, the KLA-100X, which was developed by converting the existing two-seat lightweight sport airplane KLA-100 into an electric propulsion airplane, was introduced. In this text, the main specifications, design characteristics, and performance of KLA-100X are examined. In addition, the performance of the major components of the propulsion system, in this case the propulsion motor, inverter, and battery developed for application to KLA-100X are assessed, and the control system, additionally altered according to electric propulsion modification, is explained. Finally, the applicability of the developed major components to an electric propulsion airplane is confirmed by conducting ground and flight tests on the KLA-100X and presenting the results. In the future, the expansion of research aimed at improving the performance of current electric propulsion airplanes can be reviewed through the development of a dedicated platform for an electric propulsion airplane. [ABSTRACT FROM AUTHOR]

The rise of the renewable energy sources (RES) in microgrids has increased the impact of damping and low inertia on network stability. This gives rise to several issues in the power systems, including power fluctuations from variable RES, degradation of the frequency regulation, voltage surges, and oversupply from grid‐connected distributed generators. This paper presents a cascaded hybrid load‐frequency controller for an airport microgrid that addresses frequency fluctuations caused by load changes. It is combining a self‐adaptive fuzzy controller (SAF) and a classical two‐degree‐of‐freedom proportional integral derivative (PID) controller (2DOFPID) called CSAF‐2DOFPID. It is applied to the control section of a diesel generator, an electric aircraft energy storage system, and a demand response program. The controller parameters are optimized using a suggested hybrid differential artificial hummingbird algorithm (D‐AHA) to minimize frequency deviation. The proposed control framework is simulated on an airport microgrid comprising various components, and the impact of time delay on the controller's signals, system uncertainty is also examined. The simulation results demonstrate that the proposed self‐adaptive cascaded fuzzy controller outperforms other controllers such as PID, CF‐PID, and CF‐2DOFPID in reducing frequency fluctuations, and the D‐AHA algorithm achieves favourable results compared to other algorithms in the optimal tuning controller parameters. [ABSTRACT FROM AUTHOR]

Historically aviation has gone through periods of immense innovative growth. Today the air transport industry is in the midst of yet another revolutionary period. Advanced Air Mobility (AAM) includes technological advancements in electric and hydrogen propulsion, battery capacity and autonomy, resulting in the development of a new generation of electric and hybrid-electric aircraft. These emerging technologies and new aircraft show promise in addressing historical concerns such as noise, safety, and negative environmental impacts. AAM has the potential to revolutionise the way we live by serving as the catalyst to robust, sustainable transport systems for people and goods. AAM can assist with emergency response, medical transport, reduced travel times, improve accessibility and reduce harmful emissions. Airports are an essential part of the transport infrastructure, serving as hubs for air travel, cargo shipments and emergency response centres in the wake of natural disasters. With the rise of AAM technologies, airports will need to adapt and prepare to accommodate these new types of aircraft. Each airport is unique and airport management will need to understand not only the potential of AAM but the capabilities of the airport itself. This paper aims to capture what the aviation industry has been, what it could be through AAM, lessons learned while planning for AAM, and how airports can use critical success factors to evaluate their readiness and plan for this innovative era. [ABSTRACT FROM AUTHOR]

This study focuses on the feasibility of electric aircraft operations between the Caribbean islands of Aruba, Bonaire, and Curaçao. It explores the technical characteristics of two different future electric aircraft types (i.e., Alice and ES-19) and compares their operational requirements with those of three conventional types currently in operation in the region. Flight operations are investigated from the standpoint of battery performance, capacity, and consumption, while their operational viability is verified. In addition, the CO2 emissions of electric operations are calculated based on the present energy mix, revealing moderate improvements. The payload and capacity are also studied, revealing a feasible transition to the new types. The impact of the local climate is discussed for several critical components, while the required legislation for safe operations is explored. Moreover, the maintenance requirements and costs of electric aircraft are explored per component, while charging infrastructure in the hub airport of Aruba is proposed and discussed. Overall, this study offers a thorough overview of the opportunities and challenges that electric aircraft operations can offer within the context of this specific islandic topology. [ABSTRACT FROM AUTHOR]

Electric vertical take-off and landing (eVTOL) aircraft are becoming more and more attractive due to the improvements in electric road vehicles, and the mounting demand for new urban air mobility. As here discussed, due to the low specific energy density of batteries, hybridization of the propulsion system with fuel chemical energy storage and electricity production on board by either an internal combustion engine and generator, or fuel cells stack, appears to be a better avenue to deliver performance (cruise speed, range, and payload) than using only large and heavy batteries at least through 2030. • Range and efficiency for plug-in electric vertical takeoff and landing (eVTOL) aircraft can be enhanced. • This involves using fuel chemical energy storage for electricity generation onboard. • This electricity generation may occur by internal combustion engines (ICEs) and generators. • Alternatively, it may occur by fuel cells (FCs). [ABSTRACT FROM AUTHOR]

For any novel means of transportation to thrive, its success hinges on the willingness of prospective customers to adopt the new system. To explore consumer willingness to participate in Advanced Air Mobility (AAM) by flying on electric vertical takeoff and landing (eVTOL) aircraft, an online survey of 975 individuals in the U.S. was conducted using an existing Willingness to Fly (WTF) scale designed specifically for assessing the acceptance of new aviation technologies and services. Most respondents expressed interest in flying on an eVTOL but planned to wait a few months after service starts before participating in AAM. Overall, the most frequent responses were "agree" and "strongly agree" with being WTF in eVTOLs. The survey offered four different eVTOL flight scenarios, with respondent WTF decreasing as weather or conditions deteriorated. Images of specific eVTOL models were used to assess WTF on each aircraft type. The vehicle with the most unique type of powerplants resulted in the lowest reported WTF. The study also analyzed the WTF of flying on eVTOLs across various demographic attributes. Results showed significant differences between genders, with males having a higher average WTF score. There was a weak negative correlation between WTF and age. Married respondents had the highest WTF, followed by single persons. WTF varied significantly across types of employment, income, and educational attainment. The highest WTF scores were found in the $50,000-74,999 range, with urban respondents having higher WTF than those in suburban and rural locations. Safety and cost were the top two concerns among all levels of WTF. The combination of employment status and marital status was found to be most correlated to WTF. By comprehending the inclination of consumers to travel in eVTOL aircraft, policymakers, manufacturers, and stakeholders can garner valuable insights into market demand, consumer preferences, sustainable transportation, and environmental considerations. Identifying characteristics that support or inhibit customer acceptability can assist in overcoming resistance to adoption and lead to more effective implementation of eVTOLs. Public outreach and education may be warranted to promote familiarity and passion among potential users, increasing interest and involvement. Recommendations for future research include repeating the study with an international sample and exploring willingness to pay for AAM services. [ABSTRACT FROM AUTHOR]

The transient anti‐plane problem of a functionally graded magneto‐electro‐elastic (FGMEE) rectangular plane weakened by several embedded and edge cracks under various boundary conditions is solved. First, the solutions to the dynamic magneto‐electro‐elastic dislocation in the finite rectangular domain are derived by employing Laplace and finite Fourier cosine transforms. The solutions can be utilized to construct the singular integral equations in Laplace transform domain for FGMEE rectangular plane with multiple embedded and edge cracks. The integral equations arising from dislocation solutions have Cauchy‐type singularities with unknown dislocation density functions. These unknown functions may be obtained by reducing the integral equations into a system of linear algebraic equations, hereby, the dynamic stress intensity factors (DSIFs) for several arbitrarily embedded and edge cracks are obtained. The overshoots of dynamic stress intensity factors are shown to be intensely affected by the rectangular plane dimensions, length and position of the cracks, loading parameter, and negative or positive gradient index. Highlights: The dynamic magneto‐electro‐elastic dislocation is solved in the rectangular plane.A cracked rectangular functionally graded magneto‐electro‐elastic plane is investigated.The analysis can be applied to any number of embedded and edge cracks.The effects of boundary conditions and geometry of the plane on DSIFs are studied. [ABSTRACT FROM AUTHOR]

This article proposes an experimental characterization of the currents of inductive, capacitive and linear loads in order to obtain an extraction of the reference currents for harmonic compensation by the use of an adaptive hybrid filter TLC, which offers advantages such as the reduction of switching losses during the injection of currents into the network, limitation of resonance problems and above all low energy consumption at the DC bus level, thus allowing obtaining standardized results from 105 V. Compared to existing models in the literature, which require 600 V for the same performance, this article simultaneously offers two contributions. The first one is articulated around the advantages offered by the TLC hybrid architecture of the presented prototype and the second one is focused on the experimental characterization of the currents of the different loads. Therefore, an implementation of the H-infinity command is applied to the TLC hybrid filter in the first section followed by an experimental characterization by using a test bench in the second section. The results obtained with this algorithm give THDs conforming to the IEEE 519-2014 standard and are very significant when compared to the results obtained with other robust and stochastic control algorithms taken under the same conditions and applicable to systems intelligent electrics with API-Siemens modules. [ABSTRACT FROM AUTHOR]

The fast‐charging capability of rechargeable batteries is greatly limited by the sluggish ion transport kinetics in anode materials. Here we develop an iodized polyacrylonitrile (I‐PAN) anode that can boost the bulk/interphase lithium (Li)‐ion diffusion kinetics and accelerate Li‐ion desolvation process to realize high‐performance fast‐charging Li‐ion batteries. The iodine immobilized in I‐PAN framework expands ion transport channels, compresses the electric double layer, and changes the inner Helmholtz plane to form LiF/LiI‐rich solid electrolyte interphase layer. The dissolved iodine ions in the electrolyte self‐induced by the interfacial nucleophilic substitution of PF6− not only promote the Li‐ion desolvation process, but also reuse the plated/dead Li formed on the anode under fast‐charging conditions. Consequently, the I‐PAN anode exhibits a high capacity of 228.5 mAh g−1 (39 % of capacity at 0.5 A g−1 delivered in 18 seconds) and negligible capacity decay for 10000 cycles at 20 A g−1. The I‐PAN||LiNi0.8Co0.1Mn0.1O2 full cell shows excellent fast‐charging performance with attractive capacities and negligible capacity decay for 1000 cycles at extremely high rates of 5 C and 10 C (1 C=180 mA g−1). We also demonstrate high‐performance fast‐charging sodium‐ion batteries using I‐PAN anodes. [ABSTRACT FROM AUTHOR]

Due to the high power and energy demands of large aircraft and low energy density of batteries, parallel hybrid-electric propulsion (HEP) is an in-between solution to reduce carbon emissions instead of full-electric propulsion. Considering the long in-service time, parallel HEP retrofit of existing large commercial or transport aircraft is favorable for technical risks and economic values. To enhance the reliability of the analysis, a comprehensive parallel HEP retrofit study of a narrowbody airliner is carried out in this paper. At first, efficient and accurate aerodynamic and engine deck surrogate models are built to include multidisciplinary impacts. To capture the off-design performance, a detailed flight mission is modeled based on exact flight dynamic equations, which is solved in a time-stepping manner. Then, the hybridization levels and battery usage strategy are thoroughly investigated. Besides, fuel burn, carbon emissions, and total energy consumption performance is studied for fixed take-off weight and selected flight range scenarios. The results show that the total energy in flight can be reduced by 7.9% and fuel combustion and carbon emissions can be reduced by 13.2% for the 2000 km flight distance case compared to the reference case. The greenhouse gas (GHG) emission reductions are 3059.8 kg CO2, 1220.0 kg H2O, 0.1937 kg SO4, and 0.0387 kg soot. As our methods have incorporated reliable multidisciplinary data and off-design features, the results and conclusions on the parallel HEP retrofit of large aircraft for carbon emission reductions and sustainable aviation goals are more relevant. [ABSTRACT FROM AUTHOR]

A unique configuration based on internally integrated electrodes is proposed for flexible hybrid zinc-ion capacitor (HZIC) devices. An in-depth charge storage process is studied, confirming the high electrochemical promise of HZICs for future practical applications. [ABSTRACT FROM AUTHOR]

In order to achieve high performance, a novel method is proposed in this paper. It involves solving an optimization problem by reducing the energy consumption of an aircraft in determining the optimum production positions of the an "electric aircraft propulsion system" during the climb and cruise phases. The embarkation and embarking phases must be successful given the limitations. The suggested approach is used to design the propulsion system of a specific two-seat electric aircraft for testing reasons. Over the past ten years, "electric and hybrid electric propulsion" for aero planes has drawn a lot of attention. Although studies have increasingly shown the possibilities for overall gains in fuel efficiency or missions' fluidity of new aircraft types, the primary driving for industrial interest has been to minimize emission from combustion exhaust gasses and noise. This research examines a hypothetical new kind of base jumper lift mission aircraft. The possibility of electric hybridization for this purpose is examined in comparison to traditional conventional propulsion systems. The TOPSIS method uses comparing the best solution to establish order preference. It's one of the numbers of co choice (MCDM) methods that is now use most. The TOPSIS approach was primarily created to work with data that only had real values. Since it might be challenging to produce accurate estimation of alternatives with regard to local criteria in many situations, these estimations are frequently regarded as gaps. The TOPSIS method has been extended for intervals in a few studies, although these developments are based on various heuristic methods for defining adaptive and maladaptive optimal solutions. True values or ranges that cannot be reached in the matrix provide these ideal answers. In this research, we offer a new direct way to interval expansion of a TOPSIS method that is free of heuristics assumptions and constraints of existing approaches because this is in conflict with the basics of the original TOPSIS method. [ABSTRACT FROM AUTHOR]

Hybrid quad‐plane unmanned aerial vehicles (UAVs), which combine the advantages of multicopters and fixed‐wing UAVs, are gaining increasing attention. However, quad‐planes are characterized by complex structures, high nonlinearity, strong coupling, and three flight regimes (hover, transition, and fixed‐wing flight), which bring great challenges to the research of their control laws. This article aims to design control laws for a quad‐plane in fixed‐wing and hover flight regimes based on a robust nonlinear control method, incremental nonlinear dynamic inversion (INDI), so that the quad‐plane can follow a given path autonomously. Firstly, a mathematical model of the quad‐plane is established on the basis of kinematics and dynamics. Subsequently, cascade control structures are proposed and divided into inner and outer loops. A control law is designed for each control loop based on INDI. To improve the performance of the designed control law, reference models are added to the inner loops to shape the input commands and provide feedforward inputs. Finally, simulation results corroborate the performance and robustness of the proposed control law. Compared with the control law designed by active disturbance rejection control and proportional‐integral‐derivative control methods, the INDI‐based control law is more robust. [ABSTRACT FROM AUTHOR]

Li-ion batteries are the main power source used in electric propulsion applications (e.g., electric cars, unmanned aerial vehicles, and advanced air mobility aircraft). Analytics-based monitoring and forecasting for metrics such as state of charge and state of health based on battery-specific usage data are critical to ensure high reliability levels. However, the complex electrochemistry that governs battery operation leads to computationally expensive physics-based models; which become unsuitable for prognosis and health management applications. We propose a hybrid physics-informed machine learning approach that simulates dynamical responses by directly implementing numerical integration of principle-based governing equations through recurrent neural networks. While reduced-order models describe part of the voltage discharge under constant or variable loading conditions, model-form uncertainty is captured through multi-layer perceptrons and battery-to-battery aleatory uncertainty is modeled through variational multi-layer perceptrons. In addition, we use a Bayesian approach to merge fleet-wide data in the form of priors with battery-specific discharge cycles, where the battery capacity is fully available or only partially available. We illustrate the effectiveness of our proposed framework using the NASA Prognostics Data Repository Battery dataset, which contains experimental discharge data on Li-ion batteries obtained in a controlled environment. [ABSTRACT FROM AUTHOR]

An electric wheel hybrid power system is designed for driving a large single-aisle passenger aircraft during the take-off and ground taxi phases, which consists of an APU, an energy storage system, and a motor. In the taxi phase, the electric wheel hybrid power system works alone, and the turbofan engine does not work, reducing fuel consumption and pollution emissions. During the take-off rolling phase, the electric wheel hybrid power system and turbofan engine work together to reduce the thrust requirement of the turbofan engine. This article establishes an aircraft kinematic model, hybrid power system model, and a mechanical wheel model. The feasibility of the collaborative work of the electric wheels and the turbofan engines is verified by simulations. By utilizing the established hybrid system of electric motor wheels, the fuel consumption can be reduced, and the emissions of CO, HC, and NOX can also be diminished to varying degrees. The input of motor power leads to lower turbine inlet temperature, thereby enhancing the turbofan engine's service life by approximately 4.3% and saving operational costs. [ABSTRACT FROM AUTHOR]

This research paper delves into the longitudinal wind tunnel tests conducted on the 19-passengers aircraft model of the Italian PROSIB project. The concept is an innovative small air transport airplane with distributed propellers and hybrid-electric powerplant. The primary objective was to assess its stability and control characteristics in power-off conditions. In addition to the usual investigation of the aircraft components, the study introduced a belly-mounted pod, which served as a battery storage unit, and explored two distinct tail configurations: a body-mounted (low) tail and a T-tail (high). The results obtained from these tests generally confirmed the anticipated characteristics of the aircraft design. The experiments provided data on aerodynamic forces and moments, giving useful indications on the effects of a belly-mounted battery storage unit and tail layout on the aircraft stability and control characteristics. This information could be used by aircraft designers to size an airplane of the same class. [ABSTRACT FROM AUTHOR]

Laminar flow offers significant potential for increasing the energy-efficiency of future transport aircraft. The German Cluster of Excellence SE2A is developing a new approach for hybrid laminar flow control. The concept aims to maintain laminar flow up to 80% of the chord length by integrating suction panels at the rear part of the wing, which consist of a thin suction skin and a supporting core structure. This study examines effects of various suction panel configurations on wing mass and load transfer for an all-electric short-range aircraft. Suction panel material, as well as thickness and relative density of the suction panel core are modified in meaningful boundaries. Suction panels made from Ti6Al4V offer the most robust design resulting in a significant increase in wing mass. For the studied configurations, they represent up to 33.8% of the mass of the wingbox. In contrast, panels made from Nylon11CF or PU1000 do not significantly increase the wing mass. However, the use of these materials raises questions about their robustness under operational conditions. The results demonstrate that the choice of material strongly influences the load path within the wing structure. Ti6Al4V suction panels provide sufficient mechanical properties to significantly contribute to load transfer and buckling stiffness. Locally, the share of load transfer attributed to the suction panel exceeds 50%. In contrast, compliant materials such as Nylon11CF or PU1000 are inherently decoupled from load transfer. Unlike the thickness of the suction skin, the relative density of the core structure strongly affects the wrinkling stiffness. However, wrinkling failure did not appear critical for the examined suction panel configurations. In the present study, the mechanical properties of Ti6Al4V cannot fully be exploited. Therefore, compliant suction panels made from Nylon11CF are preferred in order to achieve a lightweight solution, provided that they meet operational requirements. [ABSTRACT FROM AUTHOR]