Progress in Aerospace Sciences最新文献

Designing an airframe is a complex process as it requires knowledge from multiple disciplines such as aerodynamics, structural mechanics, manufacturing, flight dynamics, which individually lead to very different optimal designs. Furthermore, the growing use of Carbon Fibre Reinforced Plastics (CFRP), while allowing for more design freedom, has at the same time increased the complexity of the structural designers job. This has sparked the development of Multidisciplinary Design Optimization (MDO), a framework aimed at integrating intelligence from multiple disciplines in one optimal design. Initially employed as a tool to coordinate the work of several design teams over months, MDO is now becoming an integrated software procedure which has evolved over the decades and has become a prominent tool in modern design of aerostructures.

A modern challenge in airframe design is the early use of MDO, motivated by a pressing industrial need for an increased level of detail at the beginning of the design process, to minimize late setbacks in product development. Originally employed only during preliminary design, MDO has recently being pushed into early evaluation of conceptual designs with the outlook of becoming established in the conceptual stage. Using MDO during conceptual design is a promising way to address the paradox of design. By improving each concept, evaluating whether it is capable of meeting the design requirements and computing the sensitivities of various performance measures with respect to a design change, MDO enables designers to gain valuable knowledge in a design phase, in which most of the design freedom is still available.

We hereby exhibit the contemporary trends of MDO with specific focus on composite aircraft and aerial vehicles. We present the recent developments and current state-of-the-art, describing the contemporary challenges and requirements for innovation that are in the development process by academic and industrial researchers, as well as the challenges designers face in further improving the MDO workflow. Within the European OptiMACS project, we devised a novel holistic MDO approach to integrate a number of solutions to challenges identified as industrial technological gaps. These include two-stage optimization for layers of composites, addressing the presence of process-induced distortions and consideration of advanced failure criteria, including refined local models in early design stages, and seamlessly integrating software tools in the design process. The proposed methods are integrated and tested for structural case studies and the obtained results show the potential benefits of their integration into MDO tools.

Owing to their high strengths and stiffnesses, carbon fibre reinforced composites (CFRC) are widely used in aerospace engineering for lightweight structural designs. The introduction of a wide variety of lattices into composite cylindrical shells is considered one of the most promising strategies for improving the mechanical properties and simultaneously reducing weight. Herein, the configurations and manufacturing methods of three typical types of lattice structures, namely lattice, lattice sandwich, and lattice stiffened shells, are demonstrated. Experimental investigations are presented to discuss the mechanical properties of these cylindrical shells under compression, along with their free vibration characteristics. Further, non-destructive methods, which can identify the mechanical properties and buckling loads of such shells non-destructively, are demonstrated. Moreover, multi-failure theories proposed to predict the failure loads and failure modes are presented. Finally, the development of CFRC lattice cylindrical shells in lightweight designs is summarised.

The intelligent swarm concept has attracted much interest in recent years. Intelligent swarms have been deployed in many real-world applications, such as transportations, target tracking, search and rescue. Since most of these applications usually have very complex goals, the cooperative control approaches of intelligent swarms are very important, and the requirements of better utilizations of intelligent swarms make the efficient control of swarms a critical challenge that needs to overcome. This article reviews the profound cooperative control approaches of intelligent swarms, mainly focus on three kinds of typical intelligent swarms, UAV swarm, missile swarm and hypersonic aircraft swarm. The formation control approaches and decision-making approaches are both surveyed, as well as some typical real-world scenarios. Each approach is investigated based on different criteria, which highlights its distinct advantages and disadvantages. Finally, we present some discussions and recommendations for further investigation.

Weather phenomena including wind, rain, fog, storms, etc. have large influence on road transport by reducing the speed and capacity by 5–40% in moderate cases and up to 100% in case of extreme weather situations. The existing weather service systems cannot provide accurate local weather nowcasting, because of their prediction processes, and a lack of actual measured information in the atmospheric boundary layer. Technology is ready for the development and introduction of drone-based mobile automatic weather stations to support improved road weather management. This systematic review evaluates the readiness of the required technologies through surveying a wide range of papers dealing with the introduction of drone based meteorological measurements and their utilization for road weather management. It identifies the requirements of such systems, analyses the applicability of drones for weather monitoring and nowcasting, studies the required specification of drones and their instrumentations and investigates the possible realization of planned measurements. The review results show that (i) significant societal-economic value can be generated with the improvement of nowcasting and forecasting systems for road users (ii) technology is ready for the development and introduction of new road weather monitoring and management services, however UAV weather tolerance must be improved (iii) new concepts and software solutions are required for processing the measured data and rapid sharing of nowcasting information.

Space debris is one of the most urgent issues of modern astronautics, which solution requires a systematic and coordinated efforts of international community. Several lines of action can be identified to combat the space debris threat including improvement of spacecraft and rocket designs, revision of mission programs, space traffic management, active space debris removal, and collision avoidance measures. This paper introduces the reader to the main aspects of the problem of space debris. The main attention is paid to collision avoidance and active space debris removal measures. The article contains a detailed review and comparation of existing technical solutions and approaches, as well as the most important scientific research on the dynamics and control of various active space debris removal systems. Contactless transportation systems are considered in detail as a promising direction for creating safe and reliable space debris removal systems.

Spaceflight is facing a sustainability problem in Earth orbit, where about $\text{90}\text{\%}$ of all man-made trackable objects are without functional use. Existing research activities on active debris removal are technologically complex and costly, which are potential reasons why no missions were carried out so far. Micropatterned dry adhesives inspired from climbing animals, such as geckos and beetles, have been proposed as a radically new docking and capture approach for non-cooperative targets. Their successful implementation is expected to significantly reduce the technical complexity and the overall mission cost. In this article, recent developments of micropatterned dry adhesives are reviewed with a focus on space applications and their use for active debris removal. The problem and solutions for active debris removal are analyzed and open issues that need to be addressed by future work are discussed.

Machine learning (ML) has been increasingly used to aid aerodynamic shape optimization (ASO), thanks to the availability of aerodynamic data and continued developments in deep learning. We review the applications of ML in ASO to date and provide a perspective on the state-of-the-art and future directions. We first introduce conventional ASO and current challenges. Next, we introduce ML fundamentals and detail ML algorithms that have been successful in ASO. Then, we review ML applications to ASO addressing three aspects: compact geometric design space, fast aerodynamic analysis, and efficient optimization architecture. In addition to providing a comprehensive summary of the research, we comment on the practicality and effectiveness of the developed methods. We show how cutting-edge ML approaches can benefit ASO and address challenging demands, such as interactive design optimization. Practical large-scale design optimizations remain a challenge because of the high cost of ML training. Further research on coupling ML model construction with prior experience and knowledge, such as physics-informed ML, is recommended to solve large-scale ASO problems.

Increasing interest in development of very low Earth orbit (VLEO) has attracted more and more researchers to study atmosphere-breathing electric propulsion (ABEP) system in past several decades. This system can use rarefied atmospheric particles as the propellant of electric thrusters, and maintain a long lifetime mission without carrying any propellant from ground. As the key component of system, intake device can realize the collection and compression of atmospheric particles within limited frontal area, which determines the performance of whole ABEP system. This review summarizes the previous studies to develop intake devices, evaluates the corresponding performance and understands the model involved, including atmosphere model, flow physic model and so on. In addition, several continued researches for intake device are also presented, including ground experiment technologies, intake surface material development, space compressor and liquefaction technology. Wherever possible, comments have been provided to provide useful reference to researchers engaged in intake device for ABEP system.

The impressive maneuverability demonstrated by birds has so far eluded comparably sized uncrewed aerial vehicles (UAVs). Modern studies have shown that birds’ ability to change the shape of their wings and tail in flight, known as morphing, allows birds to actively control their longitudinal and lateral flight characteristics. These advances in our understanding of avian flight paired with advances in UAV manufacturing capabilities and applications has, in part, led to a growing field of researchers studying and developing avian-inspired morphing aircraft. Because avian-inspired morphing bridges at least two distinct fields (biology and engineering), it becomes challenging to compare and contrast the current state of knowledge. Here, we have compiled and reviewed the literature on flight control and stability of avian-inspired morphing UAVs and birds to incorporate both an engineering and a biological perspective. We focused our survey on the longitudinal and lateral control provided by wing morphing (sweep, dihedral, twist, and camber) and tail morphing (incidence, spread, and rotation). In this work, we discussed each degree of freedom individually while highlighting some potential implications of coupled morphing designs. Our survey revealed that wing morphing can be used to tailor lift distributions through morphing mechanisms such as sweep, twist, and camber, and produce lateral control through asymmetric morphing mechanisms. Tail morphing contributes to pitching moment generation through tail spread and incidence, with tail rotation allowing for lateral moment control. The coupled effects of wing–tail morphing represent an emerging area of study that shows promise in maximizing the control of its morphing components. By contrasting the existing studies, we identified multiple novel avian flight control methodologies that engineering studies could validate and incorporate to enhance maneuverability. In addition, we discussed specific situations where avian-inspired UAVs can provide new insights to researchers studying bird flight. Collectively, our results serve a dual purpose: to provide testable hypotheses of flight control mechanisms that birds may use in flight as well as to support the design of highly maneuverable and multi-functional UAV designs.

Flying insects are interesting dipteras with an outstanding wing structure that makes their flight efficient. It is challenging to mimic flying insects and create effective artificial flapping drones that can imitate their flying techniques. The smaller insect-size drones have remarkable applications, but they need lightweight and minimal connecting structures for their transmission mechanism. Many operating methods, such as the traditional rotary actuation method and non-conventional oscillatory mechanisms with multiple transmission configurations, are popularly adopted. The classification and recent design innovations with flapping actuation mechanism challenges, particularly bio-inspired (biomimetics) and bio-morphic types of flapping-wing aerial vehicles from micro to pico-scale, are discussed in this review paper. For ease of understanding, we have attempted to depict the actuation mechanisms in the form of block diagrams. The ability of hybrid efficient mechanisms to improve the flapping frequency of wings and flapping actuation design process, including other parameters, such as flapping angle, lift generation, and hovering ability with current driving mechanisms, is also discussed. Depending on their endearing resemblance, we have segregated Flapping-Wing Micro Air Vehicle (FWMAV) design patterns like birds, small birds, nano hummingbirds, moths, bats, biomorphic types, flapping test bench models, and fully flyable models, which are characterized by their flight modes. Important flapping actuation systems that can be used to achieve hovering capability are highlighted. The actuation mechanisms' specifications and configurations are expanded by focusing on the need of flapping frequency and stroke angle controllability via the linkage mechanisms with insight into flapping patterns. Besides that, the requirements for the sustainability of flying patterns during manual and automatic launches were investigated. In addition, the different researchers' annual progress on their Flapping-wing models has been emphasized. The best performing prototypes with their flapping actuation mechanism contributions to achieving better lift and long-duration flight sustainability are articulated through ranking. An insight into some of the significant challenges and future work on flapping performance levels are also discussed.