Search Results (202)

The evolution of modern warfare and civil exploration requires platforms that can operate seamlessly across the air–water interface. The folding-wing Hybrid Air and Underwater Vehicle (FUD) has emerged as a transformative solution, combining the high-speed cruising capabilities of fixed-wing aircraft with the stealth characteristics of underwater navigation. This review thoroughly analyzes the advancements and challenges in folding-wing FUD technology. The discussion is framed around four interconnected pillars: the overall design driven by morphing technology, adaptation of the propulsion system, multi-phase dynamic modeling and control, and experimental verification. The paper systematically compares existing technical pathways, including lateral and longitudinal folding mechanisms, as well as dual-use and hybrid propulsion strategies. The analysis indicates that, although significant progress has been made with prototypes demonstrating the ability to transition between air and water, core challenges persist. These challenges include underwater endurance, structural reliability under impact loads, and effective integration of the power system. Additionally, this paper explores promising application scenarios in both military and civilian domains, discussing future development trends that focus on intelligence, integration, and clustering. This review not only consolidates the current state of technology but also emphasizes the necessity for interdisciplinary approaches. By combining advanced materials, computational intelligence, and robust control systems, we can overcome existing barriers to progress. In conclusion, FUD technology is moving from conceptual validation to practical engineering applications, positioning itself to become a crucial asset in future cross-domain operations. Full article

This paper presents a unified aerodynamic design and optimization framework for morphing Blended-Wing-Body (BWB) Unmanned Aerial Vehicles (UAVs) operating in subsonic and near-transonic regimes. The proposed framework integrates parametric CAD modeling, Computational Fluid Dynamics (CFD), and surrogate-based optimization using Response Surface Methodology (RSM) to establish a generalized approach for geometry-driven aerodynamic design under multi-Mach conditions. The study integrates classical aerodynamic principles with modern surrogate-based optimization to show that adaptive morphing geometries can maintain efficiency across varied flight conditions, establishing a scalable and physically grounded framework that advances real-time, high-performance aerodynamic adaptation for next-generation BWB UAVs. The methodology formulates the optimization problem as drag minimization under constant lift and wetted-area constraints, enabling systematic sensitivity analysis of key geometric parameters, including sweep, taper, and twist across varying flow regimes. Theoretical trends are established, showing that geometric twist and taper dominate lift variations at low Mach numbers, whereas sweep angle becomes increasingly significant as compressibility effects intensify. To validate the framework, a representative BWB UAV was optimized at Mach 0.2, 0.4, and 0.8 using a parametric ANSYS Workbench environment. Results demonstrated up to a 56% improvement in lift-to-drag ratio relative to an equivalent conventional UAV and confirmed the theoretical predictions regarding the Mach-dependent aerodynamic sensitivities. The framework provides a reusable foundation for conceptual design and optimization of morphing aircraft, offering practical guidelines for multi-regime performance enhancement and early-stage design integration. Full article

To improve the continuous chordwise bending performance of morphing wings, this study proposes a rigid–flexible coupled wing rib structure and its control strategy. Initially, the optimal rigid–flexible hybrid configuration was optimized via the mean camber line parameterization and genetic algorithm. For the flexible segment, topology optimization was conducted using the load path method, followed by subspace-based shape–size alternating optimization; bionic “longbow” curved beams and ‘S’-shaped substructures were adopted to enhance deformability. Biomimetic pneumatic muscles were used as actuators, and a fuzzy-adjusted PI sliding mode controller was designed to address the issue that traditional PI sliding mode controllers cannot achieve precise control under non-optimal parameters or when there is a significant difference in deformation targets. Experimental results show that when the flexible rib deflects by 15°, the three-rib wing box achieves a 30° deflection, with stresses within the allowable limit of 7075Al-T6 (540 MPa) and a deformation error of only 7.6%. For the 15° downward bending control, the adjustment time is 6.06 s, the steady-state error is 0.19°, and the overshoot is 1.8%. This study verifies the feasibility of the proposed rigid–flexible coupled structure and fuzzy PI-SMC, providing a technical reference for morphing aircraft. Full article

The current study presents a holistic technology evaluation and integration methodology for enhancing the aerodynamic efficiency and performance of a tactical, fixed-wing Blended-Wing-Body (BWB) Unmanned Aerial Vehicle (UAV) through the synergetic integration of several aerodynamic and performance-enhancing technologies. Based upon several individual technology investigations conducted in the framework of the EURRICA (Enhanced Unmanned aeRial vehicle platfoRm using integrated Innovative layout Configurations And propulsion technologies) research project for BWB UAVs, a structured Technology Identification, Evaluation, and Selection (TIES) is conducted. That is, a synergetic examination is made involving technologies from three domains: configuration layout, flow control techniques, and hybrid-electric propulsion systems. Six technology alternatives, slats, wing fences, Dielectric Barrier Discharge (DBD) plasma actuators, morphing elevons, hybrid propulsion system and a hybrid solar propulsion system, are assessed using a deterministic Multi-Attribute Decision Making (MADM) framework based on Technique for Order Preference by Similarity to Ideal Solution (TOPSIS). Evaluation metrics include stall velocity (V_s), takeoff distance (s_g), gross takeoff weight (GTOW), maximum allowable GTOW, and fuel consumption reduction. Results demonstrate that certain configurations yield significant improvements in low-speed performance and endurance, while the corresponding technology assumptions and constraints are, respectively, discussed. Notably, the configuration combining slats, morphing control surfaces, fences, and hybrid propulsion achieves the highest ranking under a performance-future synergy scenario, leading to over 25% fuel savings and more than 100 kg allowable GTOW increase. These findings provide quantitative evidence for the potential of several technologies in future UAV developments, even when a novel configuration, such as BWB, is used. Full article

This project’s focus is to create a morphing wing with variable geometry that will improve aerodynamic performance. The NACA 0018 airfoil, known for its stable aerodynamic characteristics and symmetrical shape, is chosen as a base airfoil for modification in this approach. To investigate the effects of flexible trailing edge deformation under aerodynamic loading, various new morphing airfoil designs have been designed and analyzed. Both the performance results of a conventional hinged wing design and morphing airfoil designs were compared. Identifying the most effective airfoil design that could produce higher lift-to-drag ratios, less turbulence, and better overall aerodynamic behavior was the main goal. Because of its elasticity and flexibility, natural rubber latex (Hevea brasiliensis) was utilized as the primary skin material. This allows for a seamless, hinge-free morphing wing. To evaluate aerodynamic efficiency, structural integrity, and material behavior under various situations, computational fluid dynamics simulations were carried out. The most promising airfoil design was determined based on performance. By reducing drag, increasing lift, and reducing mechanical complexity, this new approach offers a sustainable and effective substitute for traditional wing designs, advancing the development of adaptive aeronautical structures. Full article

Aphids have two general types of morphs: alate and apterous. While apterous morphs exploit existing local resources, the alate morphs disperse in search of proper host plant species for settlement and reproduction. Acquiring information on the position of the body and wings requires a set of various sensory organs, which provide visual, olfactory, and proprioceptive information. The latter ones are provided through various sensilla, also located on the wings. Here, we present data on the cuticular pegs located on the membranous part of the tegula in alate aphids of the subfamily Eriosomatinae. These cuticular pegs, located on the distal part of the tegula, seem to have a sensory function, but their functional mode is unknown. It is hypothesized that they play either a mechanical function during movement of the wing, or are a part of the chordotonal organ, often located near the base of the wing in insects. Full article

This research presents the application of Reinforcement Learning (RL) techniques to optimise aerodynamic profiles in real time, within the context of morphing wings. By implementing Proximal Policy Optimisation (PPO), a methodology has been developed that learns to satisfy both aerodynamic objectives and complex geometric constraints, such as internal spatial limitations or payload integration volumes. The approach achieves an effective balance between performance and constraint satisfaction while maintaining low computational cost and millisecond-level optimisation speed. A scalable tool has been developed for real-time optimisation in such contexts, with applications in adaptive design for both manned and unmanned aviation. Full article

Understanding the dispersal capacity of Triatoma infestans, the main vector of Chagas disease in South America, is vital for vector control and managing recolonization after insecticide use. This study compares the seasonal frequency of melanic and non-melanic T. infestans morphs in Northwestern Córdoba Province, Argentina, and examines their association with environmental variables, morphometric traits, nutritional status, and flight capacity. Insects were collected at the beginning and end of the warm season. Dorsal coloration, morphometric traits, nutritional status, flight-related indices, climatic variables, and vegetation cover were recorded. Chromatic morph frequencies were analyzed using chi-square tests. Biological predictors were identified through multi-model inference, and environmental associations explored with Canonical Correspondence Analysis. Melanic individuals decreased from early to late warm season, especially males. Wing loading correlated strongly with morphotype, being higher in non-melanic forms. Pronotum size were also a significant predictor. Nutritional status had no clear effect. Cattle pasture cover and rainfall influenced morph frequency, mainly in males. These results reveal a complex interaction between phenotypic and environmental factors shaping color morph variation, highlighting the importance of understanding these dynamics to optimize vector surveillance and control in areas prone to reinfestation. Full article

One of the tasks of the FutureWings project, funded by the European Commission within the 7th framework, was to numerically validate the mechanical behavior of a wing whose deflections had to be controlled via a suitable distribution of piezoelectric patches. Starting from a reference geometry (a NACA 0012 airfoil), wing profiles were implemented and analyzed using the fluid–structure interaction analysis technique. The wing section was designed with a morphing profile in which both the front and rear parts self-deform via piezoelectric patches that serve actuators glued to the skin of the profile. A Macro Fiber Composite (MFC) was used as the piezoelectric actuator. Aeroelastic analyses were performed at low Mach numbers under the sea-level flight condition. Analysis of the technical solution was based on an examination of the aerodynamic coefficients and polar curves of the profile, as the control voltage of the patches can vary. The results were compared with those available in the literature. As a preliminary step, this work contributes to examining the current technical possibilities of this technology relating to the application of piezoelectric patches as actuators in the field of aerostructures. Full article

This work presents a low-fidelity optimization method for a compliant morphing wing trailing-edge structure, developed to achieve multiple optimized aerodynamic shapes under combined aerodynamic and control loads using a single actuation pathway. Typically, multiple shape configurations are avoided due to conflicting structural requirements that increase optimization complexity. To address this, a parameterization method based on practical considerations of compliant trailing-edge structures is introduced. A particle swarm optimization algorithm is employed, with multi-objective criteria handled through a penalty-based approach. The algorithm is demonstrated by optimizing the trailing edge for one and two aerodynamic configurations with high accuracy, achieving typical shape deviations of 0.04% and 0.08% relative to the chord for two shapes, and as low as 0.023% for a single shape. Several compliant structures are generated, manufactured, and tested for shape accuracy, including in a wind tunnel to evaluate aerodynamic performance. Experimental investigations confirm the feasibility of achieving two aerodynamic shape configurations with a single structure and show that the proposed methodology can improve the lift-to-drag ratio of a wing section with a deflected compliant trailing edge by more than 12.4% compared to conventional flaps at the same deflection. Full article

In the research and development system of bat-like flapping-wing flying robots, lift modeling and numerical analysis are the key theoretical basis, which will directly affect the construction of the body structure and flight control system. However, due to the complex three-dimensional flapping motion mechanism of bats and the flexible deformation characteristics of their wing membranes, the existing lift theory lacks a mature calculation method suitable for bionic flapping-wing flying robots. In this paper, the wing membrane deformation mechanism of a bat-like flapping-wing flying robot is studied, and the coupling effect of wing membrane motion and deformation on flight parameters is analyzed. A set of calculation methods for flexible morphing wing membrane lift is improved by using a quasi-steady model and the blade element method. By comparing and analyzing the theoretical calculation and experimental results under various working conditions, the error is less than 4%, which proves the effectiveness of this method. Full article

Background/Objectives: The bird cherry-oat aphid, Rhopalosiphum padi, is a major global pest of cereal crops and exhibits wing polyphenism, producing both winged (dispersive) and wingless (reproductive) morphs. Methods: To identify potential RNAi targets that could specifically disrupt the migratory winged morph, we conducted a comparative transcriptomic analysis of adult aphids. Differentially expressed genes (DEGs) were identified, annotated for their functions, and analyzed for their involvement in metabolic pathways. Results: Significant differences were observed in 121 genes between morphs: 13 were upregulated in the winged morph, while 108 were downregulated. Most DEGs were enriched in lipid metabolism and circadian rhythm pathways, suggesting that wing polymorphism may be adaptively linked to energy resource allocation strategies. Conclusions: This study firstly reveals the adult-stage-specific regulatory roles of lipid metabolism and circadian rhythm pathways in wing polyphenism, identifying six candidate genes (BCORL1, AMP-L, Pfl, Lip3L, HLFL(X7), and HLFL(X4)) for RNAi-based biocontrol strategies targeting migratory morphs. Full article

This review explores recent advancements in morphing structures for Unmanned Ariel Vehicles (UAVs), focusing on mechanical designs and control strategies of quadrotors that enable real-time geometric reconfiguration. Morphing mechanisms, ranging from closed-loop linkages to bioinspired and compliant structures, are evaluated in terms of adaptability, actuation simplicity, and flight stability. Control approaches, including model predictive control, reinforcement learning, and sliding mode control, are analyzed for their effectiveness in handling dynamic morphology. The review also highlights key morphing wing concepts such as GNATSpar and Zigzag Wingbox, which enhance aerodynamic efficiency and structural flexibility. A novel concept featuring an inverted slider-crank mechanism (ISCM) is introduced, enabling dual-mode UAV operation for both aerial and terrestrial missions, which is particularly useful in scenarios like wildfire suppression where stability and operation longevity are crucial. This study emphasizes the importance of integrated design approaches that align mechanical transformation with adaptive control. Critical gaps in real-world testing, swarm coordination, and scalable morphing architectures are identified, suggesting future research directions for developing robust, mission-adaptive UAV systems. Full article

This work introduces a novel variable camber mechanism that combines the high-load capacity, structural stability, and mechanical efficiency of rigid-body mechanisms with the adaptability, lightweight design, and continuous and smooth motion of compliant mechanisms. The proposed mechanism, featuring an articulated airfoil structure with revolute joints and a cantilever beam that models and controls airfoil camber morphing, employs both standard and higher kinematic pairs to constrain mobility and facilitate camber adjustments through beam deflection and coordinated kinematic interactions. Through multidisciplinary optimization, this study determined the optimal mechanism configuration and airfoil shapes for a small fixed-wing UAV (Unmanned Aerial Vehicle), meeting its morphing and mission requirements, showing the potential for drag reduction by up to 13% across various cruise conditions, thus lowering overall mission drag and energy usage. 2D (airfoil) and 3D (wing) prototypes were built to demonstrate the working principle of the proposed mechanism and to highlight its morphing capabilities. It can morph into multiple airfoil configurations, producing continuous, smooth and efficient airfoil shapes. Moreover, the mechanism is robust, simple, and easy to manufacture, effectively harnessing the strengths of both rigid-body and compliant mechanisms. Full article

Research on morphing aircraft that can change geometry to achieve the desired performance and stability under different flight conditions has been ongoing for many years. This study provides a conceptual-level, preliminary analysis of the impact of symmetrically changing the wing sweep angle on aircraft performance and stability. The T-37B-like aircraft is selected as a base to compare the results with T-37B’s known data. The T-37B-like aircraft is modeled in both Digital DATCOM and Open VSP software. Changes in aircraft performance and stability are demonstrated for changes in the wing sweep angle between −10° and 40°. When 0° and 40° wing sweep configurations are compared, it is observed that the 40° wing sweep configuration performs better in terms of climb and range, but worse in terms of takeoff distance, glide, approach, and radius of turn. In terms of static stability, it has a positive effect on longitudinal stability. While it does not significantly affect lateral stability overall, it contributes positively to stability around the roll axis. Changing the symmetrical wing sweep angle is expected to improve certain performance and stability parameters while degrading others. A symmetrical variable-sweep wing offers advantages by adjusting to the optimal sweep angle for each flight phase. Thus, benefits can be fully utilized, and drawbacks minimized. However, it entails design, mechanical, weight, and financial costs. Therefore, whether the performance and stability benefits outweigh these costs must be evaluated on an aircraft-specific basis. Full article